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Mitigation of global warming, energy security and industrial competitiveness urge the energy-intensive pulp and paper industry (PPI) to transform energy use practices. This study investigates how the PPI has responded to the need for the energy transition in the 2000s. Finland and Sweden as forerunners of energy-efficient operation and decarbonization of the PPI are used as target countries. Understanding of changes in energy consumption is complemented using decomposition analysis (Logarithmic Mean Divisia Index Method) and the energy efficiency index approach. Analysis of companies’ investments in energy technologies is used for explaining changes in energy production. Evidence of significant development towards the more sustainable operation of the PPI was found. Energy consumption per produced unit has decreased, i.e., energy efficiency has improved. Fossil fuels have been partially replaced with bio-based alternatives. Thus, the CO2 intensity has decreased substantially. The generation of renewable electricity has increased in both countries. Examples of Finland and Sweden indicate that the PPI has great potential to contribute to CO2 emission reduction worldwide in the future as energy efficiency can be further improved, and the share of fossil fuels can be decreased increasing the use of biofuels and self-generated green electricity at least in kraft pulp mills.

The construction industry had approached a critical limit which led to the increase of cement production. The production of cement would cause a broader environmental implication. Cement production is a major source of carbon dioxide emission. Carbon dioxide gas contributes about 63.33% of global warming since the production of one ton of cement would emit about one ton of carbon dioxide to the environment. To mitigate this issue, the research community has investigated the use of waste materials that possess similar chemical properties with cement content as a material for partial cement replacement. The use of rice husk ash has shown to be a contending candidate in the literature. Therefore, this paper attempts at reviewing the performance of rice husk ash as partial cement replacement. It could be observed from the literature that concrete with 5% up to 15% of rice husk ash showed an equivalent performance to ordinary concrete in compressive, flexural, and tensile strength. Thus, rice husk ash can be used as a material replacement in concrete and reduces pollution that originates from cement production and open burning of rice husk.

Made available in DSpace on 2022-04-29T08:31:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 Organization and planning of reverse logistics networks make sustainable processes more efficient. Thus, an important sector for connecting the collection and waste paper recycling echelons is the intermediate center. In this study, a Mixed Integer Linear Programming model, which is multi-objective, multi-product, multi-level and multi-period, was developed to optimize the waste paper logistics processes of intermediate centers. The formulation includes the following echelons: collection, considering vehicle routing with different capacities; inventory of non-baling materials; baling sorted waste and inventory of bales; selling bales; disposal of non-recyclable waste. The aims of the model include: maximizing the collected waste; minimizing distances; maximizing both the production and sale of bales, and minimizing costs. According to research carried out in the literature, the developed model is a new proposal and to implement it, the Weighted Goal Programming and Revised Multi-Choice Goal Programming approaches were used to deal with multiple objectives and incorporate uncertainty into the quantity of waste available for collection. To analyze the proposed model, computational tests were executed with instances based on real data from a Brazilian company in the sector. For all performed tests, General Algebraic Modeling System 23.6.5 modeling language and CPLEX 12.2.0.2 solver were used for modeling and optimization. The results show that this study presents formulation and technological approaches that represent real situations and provide competitive solutions to the problem. Sáo Paulo State University “Júlio de Mesquita Filho” [Universidade Estadual Paulista Júlio de Mesquita Filho] School of Engineering of Guaratinguetá [Faculdade de Engenharia de Guaratinguetá] Production Department, Av. Ariberto Pereira da Cunha, 333, Portal das Colinas Agulhas Negras Military Academy [Academia Militar das Agulhas Negras] Rodovia Presidente Dutra, km 306, s/n Escola Preparatória de Cadetes do Exército Avenida Papa Pio XII 350 Jardim Chapadão Campinas - SP Brazil, Avenida Papa Pio XII, 350, Jardim Chapadão, Campinas - SP Sáo Paulo State University “Júlio de Mesquita Filho” [Universidade Estadual Paulista Júlio de Mesquita Filho] School of Engineering of Guaratinguetá [Faculdade de Engenharia de Guaratinguetá] Production Department, Av. Ariberto Pereira da Cunha, 333, Portal das Colinas

We employed a microwave-assisted two-pot in-situ deposition technique to incorporate zinc oxide particulates in the structure of filter paper to produce antimicrobial paper. The process involved successive immersion of filter paper samples in ZnSO4 (precursor solution) and NaOH (precipitating agent) to form Zn(OH)2, which transformed into ZnO during microwave treatment. Successful deposition of ZnO particles on the filter paper was confirmed via X-ray diffraction and the corresponding morphologies were observed using field emission scanning electron microscopy. The ZnO-deposited papers were tested for antimicrobial activity and were found to be more effective against Staphylococcus aureus (gram-positive) than Escherichia coli (gram-negative). Bacterial populations were reduced by up to 92 ± 2% and 57 ± 4% for S. aureus and E. coli, respectively. Also, it was found that the samples prepared using higher concentrations of ZnSO4 and NaOH exhibited better antimicrobial properties.

Free-standing flexible supercapacitive electrodes have practical application for wearable energy storage devices. In this paper, graphene paper (GP), a flexible electrode substrate, was prepared by one-step reduction of graphene oxide (GO) using HI solution. GP can be used independently as a flexible electrode with specific capacitance of 227 F/g. In order to make up for the shortage of GP specific capacitance storage, polyaniline (PANI) with high specific capacitance and good electrical conductivity was selected to composite with GP by electrochemical polymerization approach. This method to fabricate electrode material by direct electrochemical polymerization avoids the use of conductive binder and organic solvent. Owing to the specific capacitance contribution of PANI and GP, the PANI/GP composites exhibit higher specific capacitance when the polymerization time is 30 s and the polymerization voltage is 0.8 V. At 1 A/g current density, the specific capacitance of composite is up to 759 F/g, which is 3.34 times of neat GP.

The rapid economic growth and environmental concerns have led to high demands on paper and paper-based products in terms of variety, quantity, quality, and specialty. Enhancement and functionalization with additives are constantly required. Moving away from traditional petroleum-based additives, researchers have attempted to use “green” nanoadditives by introducing renewable environmentally friendly nanocellulose. This article studies the functions of nanocellulose as bio-additives (enhancer, retention and filtration reagent, and coating aid) in paper and paper products, and overviews the research development of nanocellulose-based additives and their applications in the paper industry for both efficient production and paper functionalization. The review shows that (1) a variety of nanocellulose-based bioadditives have been reported for various applications in paper and paper-based products, while commercially viable developments are to be advanced; (2) nanocellulose was mostly formulated with other polymer and particles as additives to achieve their synergistic effects; (3) major interests have concentrated on the nanocellulose in the specialty papers as representing more value added products and in the efficient utilization of recycled fibers, which remains most attractive and promising for future development. This report shall provide most useful database information for researchers and industries for paper recycling and enhancement, and paper-based products innovation and application.

The appearance and quick spread of the new severe acute respiratory syndrome coronavirus disease, COVID-19, brought major societal challenges. Importantly, suitable medical diagnosis procedures and smooth clinical management of the disease are an emergent need, which must be anchored on novel diagnostic methods and devices. Novel molecular diagnostic tools relying on nucleic acid amplification testing have emerged globally and are the current gold standard in COVID-19 diagnosis. However, the need for widespread testing methodologies for fast, effective testing in multiple epidemiological scenarios remains a crucial step in the fight against the COVID-19 pandemic. Biosensors have previously shown the potential for cost-effective and accessible diagnostics, finding applications in settings where conventional, laboratorial techniques may not be readily employed. Paper- and cellulose-based biosensors can be particularly relevant in pandemic times, for the renewability, possibility of mass production with sustainable methodologies, and safe environmental disposal. In this review, paper-based devices and platforms targeting SARS-CoV-2 are showcased and discussed, as a means to achieve quick and low-cost PoC diagnosis, including detection methodologies for viral genomic material, viral antigen detection, and serological antibody testing. Devices targeting inflammatory markers relevant for COVID-19 are also discussed, as fast, reliable bedside diagnostic tools for patient treatment and follow-up., The authors acknowledge funding through projects Eco2Covid (POCI-01-02B7-FEDER-068174) and TecniCov (POCI-01-02B7-FEDER-069745), co-funded by FEDER through COMPETE2020 and Lisboa2020. T.P., A.R.C. and A.C.M. acknowledge funding to National Foundation for Science and Technology, I.P., FCT, through their PhD grants, references DFA/BD/8606/2020, SFRH/BD/130107/2017 and SFRH/BD/115173/2016, respectively, info:eu-repo/semantics/publishedVersion

Graphene-based nanomaterials possess broad applications because of their excellent multi-functional properties. In this work, a facile self-assembling method was presented for preparing one kind of graphene oxide-based paper/hollow microspheres hybrid. It was found that most of the hollow microspheres can strongly anchored on the surface of graphene oxide paper (GOP) by an in-situ scanning electron microscope peeling testing combining with molecular dynamics (MD) simulation. In addition, the uniform distribution of hollow microspheres on the surface of GOP cannot only provide a better surface wettability, but also can effectively improve the interfacial stress-transfer capability between such hybrid and polymer matrix. Our work provides a guidance for the structural designs of graphene-based nanomaterials and broaden their applications.

Cellulose paper, a material that is naturally derived, low cost, lightweight, eco-friendly, and mechanically deformable, plays important roles in producing next-generation flexible electronics. Following the booms in the development of functional electronics, the soft actuators built from cellulose paper have attracted great attention. In this focused review, the milestones and recent achievements of cellulose paper-based actuators are summarized. Electro-, thermal, moisture and magnetic actuation mechanisms are utilized to acquire energy from external stimuli. Corresponding functional materials and available fabrication techniques like film assembly and layer deposition are described. Programmable actions for the emerging applications in bionics, paper grippers and robots are realized by pursuing different strategies to control the responding deformation. Along with a conclusion, the existing challenges and possible solutions in evaluating and improving the performance of cellulose paper are summarized in the final section.

Hydrothermal liquefaction derived hydrochar produced from industrial paper sludge was used as an adsorbent to remove phenol derivatives from an industrial wastewater stream. Removal efficiency for phenol was determined using synthetic solutions (10–150 ppm) using batch adsorption experiments at a constant solution pH (8), temperature (25 ± 2 °C) and rotary speed (150 rpm). The adsorption of phenol onto hydrochar followed a Freundlich isotherm and could be described with pseudo-second-order kinetic models. Analysis of the adsorption mechanisms showed that particle film mass transport was the rate-determining step in the adsorption process. A COD removal efficiency of 31 ± 1% was achieved for the industrial wastewater stream. All phenol components in the wastewater stream could be removed, but not all organic acids and cyclic ketones. The performance of the paper sludge-based hydrochar compared well with that of activated carbon (44% COD removal). The final phenol concentration in the wastewater stream was below the acceptable phenol concentration for industrial effluents (1 mg/L). The results show that paper sludge can be converted to a valuable marketable commodity that could reduce waste management costs for a paper mill, while also reducing the cost of expensive adsorbents. Highlights Industrial paper sludge waste was successfully converted to effective bio-adsorbent.; HTL-based biochar was used as adsorbent without any pretreatment.; 77.83% COD removal from industrial wastewater could be obtained.; Final total phenol concentration was below 1 ppm.; Bulk fluid mass transfer was the rate determining step in the adsorption process.

With the increased awareness of reusing solid wastes for higher sustainability and the concern of water pollution associated with phosphorus over-emission, there are strong interests in developing solid waste based adsorbents for purifying phosphorus-containing wastewater. As a rich calcium resource, paper mill sludge (i.e., a major solid waste from pulping industry) can be used as phosphorus removal adsorbent after calcination. Thus, in this work, a simple and clean thermally treating route has been proposed for preparing calcium-containing biochar from paper mill sludge. The effect of the physicochemical properties of paper mill sludge and its carbonization condition on phosphorus adsorption has been analyzed. Moreover, the influence of some key adsorption parameters, e.g., biochar dosage, initial pH of solution, co-existing anions, initial phosphorus concentration and contact time has also been investigated. The results showed that the phosphorus adsorption data could be fitted well with pseudo-second-order kinetic and Langmuir isothermal models. The calculated maximum adsorption capacity of the as-prepared optimal calcium-containing biochar could reach to 68.49 mg·g−1 at 25 °C. Combined with the characterization results, it can be reasonably inferred that the adsorption process was chemisorption-dominated. Lastly, the application of this spent adsorbent in agriculture field has also been discussed. In brief, this work provided a feasible strategy for converting paper mill solid waste to an environmental functional material (i.e., calcium-rich biochar) for remediation of eutrophic water.

Nitrogen-fixing bacteria (NFB) can reduce nitrogen at ambient pressure and temperature. In this study, we treated effluent from a paper mill in sequencing batch reactors (SBRs) and monitored the abundance and activity of NFB with a view to producing a sludge that could work as a biofertilizer. Four reactors were inoculated with activated sludge enriched with NFB and fed with a high C/N waste (100:0.5) from a paper mill. Though the reactors were able to reduce the organic load of the wastewater by up to 89%, they did not have any nitrogen-fixing activity and showed a decrease in the putative number of NFB (quantified with qPCR). The most abundant species in the reactors treating high C/N paper mill wastewater was identified by Illumina MiSeq 16S rRNA gene amplicon sequencing as Methyloversatilis sp. (relative abundance of 4.4%). Nitrogen fixation was observed when the C/N ratio was increased by adding sucrose. We suspect that real-world biological nitrogen fixation (BNF) will only occur where there is a C/N ratio ≤100:0.07. Consequently, operators should actively avoid adding or allowing nitrogen in the waste streams if they wish to valorize their sludge and reduce running costs. PRACTITIONER POINTS: Efficient biological wastewater treatment of low nitrogen paper mill effluent was achieved without nutrient supplementation. The sludge was still capable of fixing nitrogen although this process was not observed in the wastewater treatment system. This high C/N wastewater treatment technology could be used with effluents from cassava flour, olive oil, wine and dairy industries.

Cellulose based nanomaterials have the great potential to be applied to paper as bulk additive or coating material to improve overall final properties, especially in secondary fiber. In the present work, the effect of applying different kinds of cellulose nanofibrils (CNF) to papers obtained from recycled fibers using size press on physical, mechanical and barrier properties was investigated and compared with the sole use of starch as coating material. The coating process of CNF was carried out by the addition of size press grade starch to coating suspension. As a cellulose source, wheat straw was evaluated and CNF was obtained through oxidative and enzymatic pretreatments. Results indicate that starch/CNF suspension improves the overall paper properties. As a result of the deposition of coating suspension contains of 4 % wt. periodate-oxidized CNF onto paper surface, tensile and burst indices of papersheets increased as 52.2 % and 194.4 %. Significant decreases were observed in air permeability as 69.8 %. Compression tests also have been conducted to evaluate papersheets end-use properties. In comparison to the other pretreated CNF, due to is lower viscosity, applying periodate-oxidized CNF as size press significantly increased the mechanical properties of the papers fabricated from the recycled pulps. TUBITAK-TEYDEBTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [1505]; Scientific and Technological Research Council of Turkey, Technology and Innovation Funding Programs Directorate [1505, 5180044] This work was supported by TUBITAK-TEYDEB 1505 (The Scientific and Technological Research Council of Turkey, Technology and Innovation Funding Programs Directorate 1505), Project No. 5180044. WOS:000703585400013 2-s2.0-85108063350

This study optimizes a novel surfactant-assisted green liquor dregs (GLD) pretreatment of paper mill sludge (PMS), both of which are wastes from the kraft pulping industry, using a combined Response Surface Methodology (RSM) design. Optimized conditions give a maximal reducing sugar release of 16.38 g/L. A substantial reduction in heavy metals aluminum, chromium, cobalt, arsenic, lead, and copper after pretreatment illustrates the enhancement of substrate digestibility by reducing toxic elements. Separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) for hydrogen production are assessed. SSF produced a hydrogen yield of 3.72 mL/g, displaying a 36.26% increase from pretreated PMS compared to SHF. These findings provide insights into possible methods of reducing process duration, energy input, and costs incurred with waste disposal within the paper industry. Furthermore, improved hydrogen yield using an SSF process demonstrates the potential beneficiation of pulp and paper GLD and PMS wastes.

The fiber of paper mulberry, which is mostly grown in the East Asian region, varies in both length and width—even if from the same species—depending on the country, soil, and climate where it is grown. This accounts for differences in the quality of handmade paper between domestic and imported products. Once handmade paper is manufactured as sheets, its origin cannot be determined from a morphological perspective, regardless of macroscopic and microscopic observations. Therefore, this study attempted to determine the origin of Korean and imported products using mulberry bast fiber and handmade paper from a chemometrics perspective. The inorganic components of wood are absorbed from the soil and exist in the bark of trees; thus, metal and rare-earth elements in the bast fibers and handmade papers were quantitatively analyzed using inductively coupled plasma-atomic emission spectroscopy/mass spectrometry (ICP-AES/MS). Following this, a prediction model of their origin was constructed by applying multivariate statistical analysis, i.e., a partial least squares-discriminant analysis (PLS-DA) loading plot was constructed, which helped in identifying the discrimination factors resulting from their origin. According to the ICP-AES results, Pb was only detected in the Gyeongbuk Mungyeong dak sample of the Korean bast fibers. The Chinese bast fiber sample had high contents of Ca, and B and Zn were detected only in the Chinese bast fiber samples. Bast fiber samples from China, Japan, and Thailand showed relatively high contents of Al, Ca, and Na. Meanwhile, Cu and Zn were detected in the handmade paper manufactured from the imported materials. According to the ICP-MS results, among the Korean handmade papers, the products from Gyeongbuk Mungyeong, Andong, and Chungbuk Goesan exhibited a high U content and that from Gapyeong had high Sc, Rb, Sr, and Ba contents. Thus, the elemental analysis employed in this study effectively identified the origin of the papers. The origin prediction by PLS-DA for the domestic and imported products revealed an accuracy of 86.4% and 72.7% for ICP-AES and ICP-MS methods, respectively, which is deemed acceptable to assess the origin. We believe this method significantly contributes to determining the origin of paper mulberry bast fiber and handmade paper manufactured in East Asia.

Lignin/tannin/ZnONP composite coatings were designed for paper-based green packaging. Multiple functions, such as high strength, moisture resistance, low air permeance, heat endurance, UV aging resistance, and antibacterial/mold properties, were successfully integrated into one biobased coating. Prepolymerization improved the physical properties of coatings at high lignin contents. The best ingredient ratio was: 40% lignin, 15% tannin, and 10% ZnONPs (based on tannin weight), and the as-prepared biocoating was labeled LTZn-10. After coated with LTZn-10, the tensile strength and bursting strength of the packaging were efficiently enhanced by more than 3 times and were dramatically increased by 51.6 and 5.6 times at the wet state, respectively, which reveals that the packaging has favorable moisture resistance and it can be used in high humidity environments. Scanning electron microscopy (SEM) proved that most of the pores on the paper were blocked by the coatings, which helped to decrease the air permeance by 10.3 times. Meanwhile, ZnONPs were evenly spread on the coatings, which endowed the packaging with excellent antibacterial/mold performance. No colony or mycelium was found in the test against Gram-negative/positive bacteria and eight common molds. Besides, antibacterial activity is only available while the bacteria come in contact with the coating and no active substances were released into the culture medium, which is a good property that can keep the cargo from contamination of antibacterial agents. In addition, the coated paper presented an improved Tg and thermal degradation temperature, indicating that the coated package has favorable thermostability and can maintain its outstanding physical properties in a wider temperature range. Lignin and tannin promoted the UV stability and service life of the coated paper, as a rare physical decrease was observed after UV aging for 72 h. The function-integrated biobased coating with favorable sustainability is a good candidate to be widely used in paper-based green packaging fields.

The pulp and paper industry’s multi-tonnage liquid waste is spent cooking liquor containing lignosulfonates, which disposal and processing remains one of the most complex environmental and technological problems, which should be solved. Lignosulfonates have unique colloidal-chemical properties, which determines their high resource potential. However, lignosulfonates’ composition instability often does not provide the properties and indicators set by the consumer. Changing market conditions require constant waste monitoring and modification, that prevents the widespread lignosulfonates use in industrial practice. In this paper, the causes for the formation of lignin-containing waste and its impact on the environment are considered. A strategy for lignosulfonates utilization has been developed, as well as promising methods for these wastes processing and disposal, which will expand the use of lignosulfonates and reduce the pulp and paper industry negative impact on the environment.

Funding Information: The financial support of the Austrian Federal Ministry of Digital and Economic Affairs and the National Foundation for Research, Technology and Development , Austria, is gratefully acknowledged. We also thank the industrial partners Mondi, Canon Production Printing, Kelheim Fibres, and SIG Combibloc for their support. Publisher Copyright: © 2021 Copyright: Copyright 2021 Elsevier B.V., All rights reserved. Hydrophobization of cellulosic materials and particularly paper products is a commonly used procedure to render papers more resistant to water and moisture. Here, we explore the hydrophobization of unsized paper sheets via the gas phase. We employed three different compounds, namely palmitoyl chloride (PCl), trifluoroacetic anhydride/acetic anhydride (TFAA/Ac2O)) and hexamethyldisilazane (HMDS) which were vaporized and allowed to react with the paper sheets via the gas phase. All routes yielded hydrophobic papers with static water contact angles far above 90° and indicated the formation of covalent bonds. The PCl and TFAA approach negatively impacted the mechanical and optical properties of the paper leading to a decrease in tensile strength and yellowing of the sheets. The HMDS modified papers did not exhibit any differences regarding relevant paper technological parameters (mechanical properties, optical properties, porosity) compared to the non-modified sheets. XPS studies revealed that the HMDS modified samples have a rather low silicon content, pointing at the formation of submonolayers of trimethylsilyl groups on the fiber surfaces in the paper network. This was further investigated by penetration dynamic analysis using ultrasonication, which revealed that the whole fiber network has been homogeneously modified with the silyl groups and not only the very outer surface as for the PCl and the TFAA modified papers. This procedure yields a possibility to study the influence of hydrophobicity on paper sheets and their network properties without changing structural and mechanical paper parameters.

Superhydrophobic surfaces have high potential in self-cleaning and oil-water separation applications. We developed a three-step method for the preparation of superhydrophobic filter paper. It involved citric acid (CA) pretreatment to activate cellulose fibers, coating with cellulose nanofibrils/functionalized silica (CNFs/m-SiO2) slurry to increase surface roughness, and grafting of hexadecyltrimethoxysilane (HDTMS) to enhance water resistance. The water contact angle (WCA) and siding angle (SA) of the prepared filter paper reached 151.5° and 7.5°, respectively. The results showed that, compared to the coated filter paper without the added CNFs, the coated paper with CNFs had higher retention of m-SiO2, thus roughness required for superhydrophobic surface was achieved. Further test under frequent abrasion and acid or alkali conditions showed that CA pretreatment improved the durability of superhydrophobic filter paper due to chemical crosslinking between the modified substrate and m-SiO2. Besides, the prepared superhydrophobic filter paper had outstanding self-cleaning property and high oil-water separation efficiency for various oil-water mixtures. Therefore, it is expected to be used for the treatment of oily wastewater.

Graphical abstract Enzyme-linked immunosorbent assay (ELISA) is widely used for the detection of disease biomarkers. However, it utilizes time-consuming procedures and expensive instruments, making it infeasible for point-of-care (POC) analysis especially in resource-limited settings. In this work, a multicolorimetric ELISA biosensor integrated on a paper/polymer hybrid microfluidic device was developed for rapid visual detection of disease biomarkers at point of care, without using costly equipment. This multicolormetric ELISA platform was built on multiple distinct color variants resulted from the catalytic oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and the etching of gold nanorods (AuNRs). The vivid color changes could be easily distinguished by the naked eye, and their red mean values allowed quantitative biomarker detection, without using any sophisticated instruments. When this multicolorimetric ELISA was integrated on a paper/polymer hybrid analytical device, it not only provided integrated processing and high portability but also enabled fast assays in about 50 min due to the unique advantages of paper/polymer hybrid devices. The limit of detection of 9.1 ng/μL of the hepatitis C virus core antigen, a biomarker for hepatitis C, was achieved using this multicolorimetric ELISA platform. This multicolor ELISA analytical device provides a new versatile, user-friendly, affordable, and portable immunosensing platform with high potential for on-site detections of various viruses, proteins, and biomarkers for low-resource settings such as at home, public venues, rural areas, and developing nations. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03359-8.

The in-situ synthesis of calcium silicate in the fiber can not only meet the requirements for high loading of paper, but also make up and improve the reduction of paper performance caused by filling. In this investigation, the effects of pulp type, beating degree, fiber ratio, reaction time, rotational speed, dosage of lime milk and dispersant on calcium silicate loading and paper properties were investigated. The results showed that when the beating degree was 40 °SR, the ratio of softwood and hardwood pulp was 1:1, the reaction time was 60 min, the rotation speed was 600 r·min−1, the dosage of lime milk was 1.33 times of the theoretical amount, and the dosage of cationic polyacrylamide was 0.3 % (absolutely dry pulp), the ash content of hand-made sheet was 41.2 %, and the loading amount of calcium silicate was 26.3 %. Under this condition, the comprehensive performance of paper was the best.

A simple electrochemical approach has been strategically developed for in situ generations of ZnO nanoparticles using Zn rods as electrodes and hydrogen peroxide as the oxidant without the formation of any by-product. These ZnO nanoparticles were extended for remediation of pollutants present in paper mill effluents, and separation efficiency was found to be above 90% for hydrocarbons, 92% for lignin, 99% for phenol, and 93% of chemical oxygen demand (COD), as confirmed by gas chromatography-mass spectrometry and COD analysis. It was also observed that the experimental setup could successfully remove 99% of the color from the sample. These ZnO nanoparticles have been proven in the past to be antibacterial and were explored for its ability to inhibit the growth of both Gram-positive and Gram-negative bacteria in the effluent samples after the removal of toxic pollutants. Therefore, we proposed an electrochemical reaction for the in situ synthesis of ZnO nanoparticles for remediation of paper mill effluent as well as inhibit the bacterial growth in the treated effluent sample.

A wide variety of biomass is available all around the world. Most of the biomass exists as a by-product from manufacturing industries. Pulp and paper mills contribute to a higher amount of these biomasses mostly discarded in the landfills creating an environmental burden. Biomasses from other sources have been used to produce different kinds and grades of biomaterials such as those used in industrial and medical applications. The present review aims to investigate the availability of biomass from pulp and paper mills and show sustainable routes for the production of high value-added biomaterials. The study reveals that using conventional and integrated biorefinery technology the ample variety and quantity of waste generated from pulp and paper mills can be converted into wealth. As per the findings of the current review, it is shown that high-performance carbon fiber and bioplastic can be manufactured from black liquor of pulping waste; the cellulosic waste from sawdust and sludge can be utilized for the synthesis of CNC and regenerated fibers such as viscose rayon and acetate; the mineral-based pulping wastes and fly ash can be used for manufacturing of different kinds of biocomposites. The different biomaterials obtained from the pulp and paper mill biomass can be used for versatile applications including conventional, high performance, and smart materials. Through customization and optimization of the conversion techniques and product manufacturing schemes, a variety of engineering materials can be obtained from pulp and paper mill wastes realizing the current global waste to wealth developmental approach.

In the present study, adsorption of colour and other pollutants from agro-based paper mill effluent onto fabricated coal fly ash nanoparticles (CFA-N) have been investigated. Response surface methodology was applied to evaluate the operational conditions for maximum ouster of colour from effluent by nano structured CFA-N. Maximum reduction in colour (92.45%) and other pollutants were obtained at optimum conditions: 60 min interaction time, 60 g/L adsorbent dosage and 80 rpm agitation rate. The regression coefficient values (adjusted R2 = 0.7169; predicted R2 = 0.7539) established harmony between predicted and the experimental data. The adsorption equilibrium results matched perfectly with both Langmuir and Freundlich isotherms with maximum adsorption capacity of 250 platinum–cobalt/g. Additionally, the efficacy of CFA-N was also assessed in a continuous column mode. Furthermore, the feasibility of treated effluent for irrigation purpose was checked by growing the plant Solanum lycopersicum. Overall, the findings demonstrated the outstanding role of inexpensive and abundantly available CFA-N in treatment of paper mill effluent to the required compliance levels. HIGHLIGHTS Nano fly ash was successfully utilized for removal of colour and other pollutants from agro-based paper mill effluent.; RSM using BBD was used to optimize the operational conditions.; Quadratic models have been established for the response variables.; Fixed-bed column adsorption studies illustrated the feasibility of nano fly ash for pilot-scale applications.; The reusability of treated effluent for irrigation was examined.

Graphical abstract During epidemics, such as the frequent and devastating Ebola virus outbreaks that have historically plagued regions of Africa, serological surveillance efforts are critical for viral containment and the development of effective antiviral therapeutics. Antibody serology can also be used retrospectively for population-level surveillance to provide a more complete estimate of total infections. Ebola surveillance efforts rely on enzyme-linked immunosorbent assays (ELISAs), which restrict testing to laboratories and are not adaptable for use in resource-limited settings. In this manuscript, we describe a paper-based immunoassay capable of detecting anti-Ebola IgG using Ebola virus envelope glycoprotein ectodomain (GP) as the affinity reagent. We evaluated seven monoclonal antibodies (mAbs) against GP—KZ52, 13C6, 4G7, 2G4, c6D8, 13F6, and 4F3—to elucidate the impact of binding affinity and binding epitope on assay performance and, ultimately, result interpretation. We used biolayer interferometry to characterize the binding of each antibody to GP before assessing their performance in our paper-based device. Binding affinity (KD) and on rate (kon) were major factors influencing the sensitivity of the paper-based immunoassay. mAbs with the best KD (3–25 nM) exhibited the lowest limits of detection (ca. μg mL−1), while mAbs with KD > 25 nM were undetectable in our device. Additionally, and most surprisingly, we determined that observed signals in paper devices were directly proportional to kon. These results highlight the importance of ensuring that the quality of recognition reagents is sufficient to support desired assay performance and suggest that the strength of an individual’s immune response can impact the interpretation of assay results. Supplementary Information The online version contains supplementary material available at 10.1007/s00216-021-03317-4.

In this study, Taguchi experimental design was used to the optimize operating parameters for the degradation of paper mill effluent using electrochemical (EC) process with two-dimensional concentric aluminum tube electrodes (CATE). For this purpose, four significant experimental factors were used in four levels pH (6–9), electrolysis time (10–40 min), voltage (6–12 V) and surface area (357–624 cm(2)). The process parameters were optimized, through performing L16 orthogonal array of Taguchi technique, for the removal of chemical oxygen demand (COD) and turbidity. The percent COD and turbidity reductions were transferred into an accurate S/N ratio for a larger value is the better (LBT) response. The study presents a unique method of finding optimum combination of process parameters to illustrate their effect on the turbidity and COD reduction. The treatment conditions for the maximum elimination of the pollutants were second level of pH (7), third level of ET (30 min), fourth level of voltage (12 V) and second level of surface area (446 cm(2)). The confirmation experiment results were within the confidence intervals (CI) indicating an acceptable agreement between predicted and observed values. Based on the p-values, the electrolysis time and voltages were found to be the most significant factors for both COD and turbidity reduction. The findings of research indicated, that the Taguchi method can be used successfully for the treatment of paper industry effluent by electrochemical technique.

In this research, simultaneous quantification of cysteine (Cys) and histidine (His) using a paper-based sensor was investigated for the first time. A microfluidic paper-based sensor is a promising amino acid determination tool due to its low cost, low sample consumption, and fast analysis and is easy to make. We used SBA-15 as porous materials that are crystalline compounds formed with surfactants and TEOS as a silica source. The SBA-15 sample was characterized by X-ray diffraction, Fourier transform infrared, and scanning electron microscope techniques. The microfluidic paper-based sensors were fabricated using a wax pen, and the mesoporous SBA-15 modified filter paper. The fabricated sensors for Cys and His determination are operated based on an indicator-displacement assay. A comparative determination study of Cys and His on the sensors was carried out. The results illustrated that the addition of silica nanoporous material led to an immediate and uniform color change. The sensors were successfully exploited in the simultaneous determination of urinary Cys and His levels, thus providing the potential opportunity for clinical diagnosis. The linear range of 1.0 to 90.0 μM and 1.0 to 100 μM for His and Cys was obtained from the calibration data. The detection limits were also calculated (S/N = 3) for His and Cys of 0.5 μM and 1.5 μM, respectively. The proposed method showed a good agreement with the results achieved by a standard method.

This study focused on the applying endo-xylanases to reduce the use of bleaching agent, coupled with the production of xylooligosaccharides (XOs), in mulberry paper making. Paper mulberry pulp (PMP) was consecutively prepared from paper mulberry bark by traditional NaOH-treatment, and two types of thermostable endo-xylanase from Streptomyces thermovulgaris TISTR1948 (wild-type and recombinant endo-xylanases) were employed in the biobleaching of PMP. This process was optimized to achieve maximum XOs yields and the highest PMP quality. The optimal condition was an enzyme dosage of 125 U/g PMP at 12 h of reaction time, both in a 500 mL laboratory bottle and a 150 L reactor. The mixture obtained from the reactor was separated as liquid of XOs derived from PMP (PMP-XOs) and solid biobleached PMP. The PMP-XOs from wild-type endo-xylanase were composed of 31.6% xylopentaose (X5), 30.9% xylohexaose and higher-degree XOs (X ≥ 6), and 11.7% xylobiose (X2), whereas 76.6% of X5 and 8.6% of X2 were the main products from recombinant endo-xylanase. The PMP-XOs derived from both endo-xylanase types exhibited high antioxidant activities, reducing power, phenolic contents, and prebiotic efficacy. In addition, the application of both endo-xylanases enhanced the brightness of PMP by 5.1% and 3.5%, and reduced the kappa number by 9.1% and 3.6%, respectively. Biobleached PMP was subsequently subjected to the NaOCl bleaching step to produce the mulberry paper. This approach could reduce NaOCl consumption by 20–25%, making it an environmentally friendly alternative. The production of valuable prebiotics, such as PMP-XOs, further enhances the economic viability of this approach.

A high-barrier, strong, and antibacterial paper was fabricated by coating the acetylated cellulose solution with different contents of cinnamaldehyde (CIN) on Kraft paper. The antibacterial, antioxidant, mechanical, and barrier properties of coated paper were investigated. When the amount of CIN added in coating reached 6% v/v, the coated paper exhibited excellent antioxidant activity and antibacterial activity against Escherichia coli and Staphylococcus aureus. Notably, the dry and wet tensile strength of paper after coating was increased by 26.4 and 10.6 MPa, respectively. Furthermore, the coated papers' barrier properties against oil, water, water vapor, and oxygen were dramatically improved, especially for the water barrier rate up to 96.4%. Our coated papers with over 6% v/v CIN could extend beef's shelf-life for at least 4 days, which exhibited a promising prospect in eco-friendly antibacterial packaging.

A newly developed research topic, fabricated paper-based microfluidic sensors, was discussed in the field of low-cost environmental detection. Distinguished with the traditional dipstick or lateral-flow setups, these paper-based microfluidic sensors can serve as a tool for onsite quantitative and semi-quantitative measurements, without risks to cause environmental pollution. They have attracted increasing interest since the first easy-fabricated paper-based setup reported by Whitesides group in 2007. Most of the publications utilized paper-based sensors in clinical detection. In recent years, some groups started to use these sensors in environmental measurement, leading to precise, easy operation, low-cost, and eco-friendly methods for onsite detection. In this review, paper-based microfluidic sensors were briefly introduced, followed by literatures review and discussion for future perspectives.

BackgroundThe analysis of the quality of food is important to protect humans from food-borne or food-based illnesses caused by pathogens, such as bacteria, fungi, viruses, and protozoa. Rapid identification of these pathogens is critical to ensure food safety. Various detection and identification strategies exist; however, they are laborious and time consuming and hence the detection takes longer time. The aim of this study was to develop the specific and fast method for the detection of contaminants in milk.ResultsIn this study, we have developed a simple paper-based PCR method with minimum sample preparation process. The 16S rDNA universal primers were used for the detection of bacterial contaminants. LacZ primers were used for coliform detection which causes serious illness and hence their detection is crucial. ITS region primers were used for fungal detection. The most unique thing about this study is use of Whatman paper no. 1 as sample carrier material. We developed and validated the paper-based PCR method and used it for the detection of microbes and coliforms using milk as a representative sample.ConclusionWe evaluated this method for its suitability in the detection of contaminant microbes using different milk samples. The paper-based method could successfully detect contaminants in the milk samples and the results were comparable to the traditional microbial detection method. The traditional microbiological method takes at least 18–20 h for detecting the presence of microbes in any sample but the developed paper-based PCR method can confirm the microbial presence in 2–3 h. This is very promising especially in the testing where sample sterility is crucial.

In the tourism industry, the sales of local specialties is an important part, and the package design and integrity of the specialties are very important. This paper first introduced the support vector machine (SVM) algorithm that was used for detecting defects on the surface of paper packages. Then, the design of red wind packages was briefly described, and the simulation experiment was carried out on SVM algorithm using red wine packages with different degrees of surface defects. Proper parameters were tested using the k-fold cross-validation method. The results demonstrated that the properties of paper improved the value of packages and the SVM algorithm had better accuracy than artificial recognition in recognizing different degrees of defects on the surface of packages. In conclusion, this paper describes the application of paper in packages and provides an effective method for the defection of defects on the surface of packages. This study provides an effective references to the improvement of package values and the enhancement of package integrity.

Environmentally friendly and energy saving treatment of black liquor (BL), a massively produced waste in Kraft papermaking process, still remains a big challenge. Here, by adopting a Ni CaO Ca12Al14O33 bifunctional catalyst derived from hydrotalcite-like materials, we demonstrate the feasibility of producing high-purity H2 (∼96%) with 0.9 mol H2 mol−1 C yield via the sorption enhanced steam reforming (SESR) of BL. The SESRBL performance in terms of H2 production maintained stable for 5 cycles, but declined from the 6th cycle. XRD, Raman spectroscopy, elemental analysis and energy dispersive techniques were employed to rationalize the deactivation of the catalyst. It was revealed that gradual sintering and agglomeration of Ni and CaO and associated coking played important roles in catalyst deactivation and performance degradation of SESRBL, while deposition of Na and K from the BL might also be responsible for the declined performance. On the other hand, it was demonstrated that the SESRBL process could effectively reduce the emission of sulfur species by storing it as CaSO3. Our results highlight a promising alternative for BL treatment and H2 production, thereby being beneficial for pollution control and environment governance in the context of mitigation of climate change.

The present study reports the characterization of reverse osmosis (RO) technology at water treatment plant Cogen-2 in paper and Board mills, Pakistan. RO is a commonly used process to obtain de-mineralized water for high-pressure boiler operation in thermal power plants. Scaling and fouling in three-stage RO plants is a major challenge in chemical industry due to the use of raw brackish water in the power plant of paper and board mills. In our study, the feed water quality of RO was changed from soft water to raw water to make it economical. The cleaning frequency was increased three times than normal, which was unsafe for operation and it was required to control scaling and fouling to achieve the desired result. Differential pressures behavior of all stages for 2-month data was observed without acid treatment, and the results of Langelier Saturation Index (LSI) control parameters (temperature, pH, total dissolved solids, calcium hardness, and alkalinity) clearly showed the abnormality. To optimize scaling and fouling of RO, the LSI factor was controlled in total reject water for the next 2 months by acid treatment in feed water. Duration of chemical cleaning and membranes’ life has been extended by fouling and scaling control. Understanding the effect of operational parameters in RO membranes is essential in water process engineering due to its broad applications in drinking water, sanitation, seawater, desalination process, wastewater treatment, and boiler feed water operation. The product flow increased from 18.3 to 19.9 m3/h, and this was due to a decrease in the rejection flow from 8.2 to 6.7 m3/h. The total reject stream pressure also increased from 8.1 to 9 bar. A lower value of LSI of 1.6 is obtained in the reject water stream after the acid treatment.

By continuously varying the structure of graphene oxide paper (PRGP) using Joule heating annealing, we are able to tune its electrical conductivity (σ) and thermal diffusivity (α) in a very wide range: more than three orders of magnitude for σ (186–503009 S/m) and 10-fold for α (8.31 × 10−7 m2/s to 9.31 × 10−6 m2/s). Excellent coherency-linear relationship between σ and α is discovered although they are sustained by different carriers: electrons and phonons. Such coherency exists over two sections: σ > 2 × 104 S/m, and 103

Rewritable paper is meaningful to the recyclable and sustainable utilization of environmental resources and thus has been extensively investigated for several decades. In this work, we demonstrated an efficient and convenient strategy to fabricate rewritable paper based on reversible hydrochromism of donor-acceptor Stenhouse adducts (DASAs). The kinetics and efficiency of isomerization could be well-controlled by adjusting the surrounding temperature and humidity. Monocolored rewritable paper was prepared by coating cyclic DASA·xH2O on the paper surface. Writing, printing, stamping and patterning were realized on the rewritable paper. The information could be controllably erased by treatment in a humid atmosphere. More importantly, the rewritable paper was upgraded to multicolored by combination of two DASA materials. The color of chirography was switched by controlling the writing speed.

The salivary glands are closely associated with stress conditions and the neuroendocrine system. The concentrations of these salivary biomarkers fluctuate with a person’s disease status. Until now, salivary diagnostics have been promising; however, the analytical tools for detecting salivary biomarkers have remained burdensome due to the lack of user-friendly and cost-effective equipment. In this study, we used a microfluidic starch-coated paper-based chip to isolate ɑ-amylase from human saliva. The concentration of ɑ-amylase on the head and tail sections of the paper-based chip was compared in the presence or absence of starch. We found that ɑ-amylase was highly concentrated only in the head section of the starch-coated paper-based chip through Western blotting (WB) and enzyme-linked immunosorbent assay (ELISA). We expect our designed paper-based chip will aid in α-amylase detection technologies using saliva and small amounts of other biofluids including blood, tears, pancreatic juice, and urine.

In this elucidation, we synthesized novel molecularly imprinted polymers (MIPOH1-4) that were used as organic fillers on bagasse pulp to form cellulosic paper sheets, the formation of MIPOH1-4 from the reaction of enaminone 3 with methyl methacrylate monomer in the presence of ethylene glycol dimethyl acrylate and 2,2’-azobisisobutyronitrile. The obtained MIPOH1-4 was confirmed via FT-IR and SEM with different pore sizes. And we noticed that the increase of template 3 increases the hydrogen bond between monomer and template and gave sponge surface of MIPOH4. Furthermore, the computational energies of the template with different monomers utilize DFT/B3LYP/6-31G (d) level to know the stability of polymers and hydrogen bonding between them. So that we applied that in paper manufacture through the adsorption of MIPOH4 as an organic filler on bagasse pulp to form novel cellulosic paper sheets with different concentrations and these sheets which characteristic through FT-IR, SEM, sizing test, tensile strength, and elucidation their antimicrobial activity with theoretical and docking studies. The MIPOH4 and cellulosic paper sheets showed the thermal stability and high tendency of sizability of these paper sheets and concluded the interaction between cellulose fibers of pulp with MIPOH polymer with physical hydrogen bonding.

One of the most cited limitations of biochemical detection is its poor sensitivity, owing to the relatively high complexity of micro-samples. Moreover, some samples cannot be easily self-replicated and their abundance cannot be increased through traditional technologies. Therefore, the preconcentration of low-abundance samples is a key requirement for microfluidic biological analysis. In recent years, the ion-concentration polarization phenomenon has aroused widespread interest in the application of microfluidic technology. In addition, paper-based materials are readily available, easy to modify, and exhibit good hydrophilicity. The study of the ion-concentration polarization preconcentration of micro-samples in paper-based microfluidic chips is of considerable significance. In this review, we discuss the development and applications of ion-concentration polarization paper-based preconcentrator in the past 5 years, with emphasis on key progresses in chip fabrication and performance optimization under different conditions. The current needs and development prospects in this field have also been discussed.

Industrial effluent Management is one of the major environmental concerns, especially in developing countries under rapid industrialization. The grossly polluting industries recognized by Central Pollution Control Board (CPCB), such as Pulp and Paper Industries, poses even bigger environmental threats, owing to quantity and quality of effluent generated. This paper aimed at analyzing effluent management practices in pulp and paper industries in India, and asses the performance variability of a paper mill effluent treatment plant (ETP), as a Case Study. Majority of pulp and paper industries found to still employ conventional methods of effluent treatment. Although, most of the parameters of treated effluent are commonly reported within CPCB’s permissible discharge limits, the treatment is usually cost and energy intensive, and produce high amount of solid residuals as sludge. For the case study paper mill ETP, the treatment efficiencies of the ETP units were analyzed under variable inlet pH, TSS, TDS, BOD and COD loads. The pH variations in the range of 6.5 to 9 had little effect of COD or TSS removal, however removal efficiencies were higher for larger inlet COD or TSS loads. The results of the study could be helpful in optimizing operation of the existing ETPs, as well as, guiding on upgrading ETPs with more cost-effective and efficient units.

Microfluidic paper-based analytical devices (μPADs) have developed rapidly in recent years, because of their advantages, such as small sample volume, rapid detection rates, low cost, and portability. Due to these characteristics, they can be used for in vitro diagnostics in the laboratory, or in the field, for a variety of applications, including food evaluation, disease screening, environmental monitoring, and drug testing. This review will present various detection methods employed by μPADs and their respective applications for the detection of target analytes. These include colorimetry, electrochemistry, chemiluminescence (CL), electrochemiluminescence (ECL), and fluorescence-based methodologies. At the same time, the choice of labeling material and the design of microfluidic channels are also important for detection results. The construction of novel nanocomponents and different smart structures of paper-based devices have improved the performance of μPADs and we will also highlight some of these in this manuscript. Additionally, some key challenges and future prospects for the use of μPADs are briefly discussed.

Plant fiber classified as environmentally friendly material is a promising renewable engineering material rich in lignocellulose that can be employed in the pulp and paper industry as a substitutio...

Thermochemical parameters of A4-sized printing paper (AP), filter paper (FP), newspaper (NP), writing paper (WP), and reed pith (RP) samples were estimated using standard protocol to identify its fuel characteristics, and thermal degradation of the same was studied using thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) techniques in the temperature range of 30–800 °C at the heating rates of 10, 15, and 20 °C/min under nitrogen atmosphere. The curves of TGA and DTG exhibited four significant stages. Maximum weight loss was found to be in the second stage. Kinetic analysis was carried out in the conversion range of 0.1 to 0.7 using iso-conversational models of Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Vyazovkin, and Vyazovkin AIC (V.AIC). The average activation energies were found to be 139.90, 115.93, 212.52, 257.41, and 241.63 kJ/mol using FWO; 129.73, 103.06, 202.46, 248.38, and 231.55 kJ/mol using KAS; 145.57, 134.00, 195.29, 256, and 241.63 kJ/mol using Vyazovkin; and 140.71, 133.86, 193.14, 247.57, and 190.14 kJ/mol using Vyazovkin AIC model. Thermodynamic parameters (enthalpy change (ΔH), Gibbs free energy change (ΔG), and entropy change (ΔS)) using these models have been evaluated.

All-cellulose paper-based composites with underwater superoleophobicity and high-wet-strength were developed by casting a barrier layer of bacterial cellulose (BC) on a filter paper substrate. To optimize the pore structure of barrier layer, slow gel process of BC dispersion was conducted via acidification and solvent exchange. 1,2,3,4-butanetetracarboxylic acid was used to improve the wet strength and surface hydrophilicity through the crosslinking reaction between fibers. The underwater oil contact angles are higher than 150° in neutral environment, and slightly decrease under acid and alkali conditions. Combined with the micron-sized pore structure of BC barrier layer, the composite papers show good separation performance of oil-in-water emulsion. A denser BC layer can significantly improve the separation efficiency, but also lead to the reduction of flux. During the gelation of BC barrier layer, the increase in the ethanol/water ratio of the dispersion medium is able to increase the flux without obvious negative impact on the separation efficiency. When the ethanol/water ratio is 80%, the separation efficiency and water flux reach 99.2% and 1320 L m−2 h−1·bar−1 for the emulsified soybean oil with the average size of 13 μm, respectively. This type of all-cellulose composite papers provides a new idea for the fabrication of membrane materials for oil–water separation.

In this paper, we present a system for automatic evaluation of the quality of a question paper. Question paper plays a major role in educational assessment. The quality of a question paper is crucial to fulfilling the purpose of the assessment. In many education sectors, question papers are prepared manually. A prior analysis of a question paper might help in finding the errors in the question paper, and better achieving the goals of the assessment. In this experiment, we focus on higher education in the technical domain. First, we conducted a student survey to identify the key factors that affect the quality of a question paper. The top factors we identified are question relevance, question difficulty, and time requirement. We explored the strategies to handle these factors and implemented them. We employ various concepts and techniques for the implementation. The system finally assigns a numerical quality score against these factors. The system is evaluated using a set of question papers collected from various sources. The experimental results show that the proposed system is quite promising.

This paper aimed to modify the ignitability of the bagasse paper by using talc powder, 1,3-di-aniline-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane, and nanocellulose crystal. The formation of cellulose nanocrystals (CNCs) was detected using transmission electron microscopy (TEM), X-ray diffraction (XRD). Thermal analysis as thermal gravimetric analysis (TGA) of the specimens recorded the improvement of the highest % of ash residue at 750 °C compared to the untreated one. The shape of the flame spread was studied. The ignition properties were studied for the untreated and treated specimens by limiting oxygen index (LOI) and flame chamber (UL/94), which recorded enhancing compared to the untreated specimen. This improvement was recorded either by measuring the mechanical properties (tensile strength, burst strength, elongation, and elasticity) of the specimens. The current article showed that the treated specimen was recorded the highest values compared to the untreated one in all physical, mechanical, and ignition properties, so these treatment paper sheets may be used as fire-retardant packaging materials.

Currently, most of the collected waste medium-density fiberboards (MDF) is incinerated or landfilled, as economically viable recycling methods are yet to be developed. By steam refining waste medium-density fiberboards (MDF), it is possible to hydrolyze the incorporated resins and isolate a high yield fiber fraction. Further refining of the steam treated fibers might enable the fibers to be utilized in applications such as paper packaging, facilitating a cascading use of the waste material stream. To this end, intimate knowledge of the material is needed. In this study, the steam refined fibers of two waste MDF samples containing differing amounts of softwood and hardwood underwent refining and beating. The resulting fibers were characterized regarding their morphology and paper test sheets were produced to evaluate their strength (compression-, tensile- and tear-strength). Distinct differences in response to refining between the MDF samples were apparent. For the sample with the higher hardwood share an increase in strength properties with increasing steam treatment severities could be observed and it was possible to produce test sheets with comparable compression strength to recycled pulp for industrial corrugated paperboard. For the sample with a higher share of softwood, the steam treatment severity did not show any influence on fiber morphology or paper properties, and the resulting paper strength was low in comparison to the other steam refined waste MDF sample. Graphic Abstract

Cellulose nanofibers isolated from unbleached pulp are characterized by different surface properties due to presence of lignin at their surface, in addition to lower cost than isolated from bleached pulp. In the current work, the effect of cellulose nanofibers isolated from unbleached neutral sulfite and bleached soda rice straw pulps (so called UBCNF and BCNF) on improving paper sheet properties of unbleached and bleached rice straw pulp (so called UBP and BP) was studied. The effect on mechanical properties (tensile strength, burst strength, and tearing resistance) and physical properties (porosity and water vapor permeability) was studied. Scanning electron microscopy (SEM) was used to assist in explaining the obtained results. The result showed that using BCNF and BP resulted in better improvement in mechanical properties and also more effective in reducing porosity of paper sheets than in case of using UBCNF and UBP. These results indicated stronger bonding between nanofibers and pulps’ fibers in case of using BCNF and BP (surfaces rich in cellulose hydroxyl groups) than in case of UBCNF and UBP (surfaces rich in lignin). Water vapor permeability of paper sheets made from unbleached or bleached pulps did not significantly affect by the addition the nanofibers.

The kapok (Ceibapentandra (L.) Gaertn) seed fibre is unicellular with length up to 35 mm, however, it is covered by a hydrophobic waxy layer that limits its application in paper production. In this study, the effect of various pulping methods namely mechanical, chemi-mechanical, semichemical and chemical pulping on kapok fibre properties was investigated. Each kapok pulp was then blended with the secondary fibre recovered from kraftliner board for handsheet making to examine their reinforcing ability on strength properties. The results showed that kapok mechanical pulps (with and without dewaxing (5% (v/v) diluted detergent) and chemimechanical pulp were unable to improve the strength properties of the handsheet. Kapok pulps chemically treated with 18–25% of sodium hydroxide gave a better effect on handsheet strength properties whilst fibre treated with 20% sodium hydroxide showing the highest increment. Although the reinforcing effect of the 4% native cooked starch was slightly higher than that of the 10% kapok pulp blended in recycled paper, the recycling potential of the latter was better as all strength properties retained unchanged after recycling. The findings indicated that kapok chemical pulp is a promising reinforcing fibre source with superior recycling potential.

The development of industry and of the Internet of Things (IoTs) have brought energy issues and huge challenges to the environment. The emergence of triboelectric nanogenerators (TENGs) has attracted wide attention due to their advantages, such as self-powering, lightweight, and facile fabrication. Similarly to paper and other fiber-based materials, which are biocompatible, biodegradable, environmentally friendly, and are everywhere in daily life, paper-based TENGs (P-TENGs) have shown great potential for various energy harvesting and interactive applications. Here, a detailed summary of P-TENGs with two-dimensional patterns and three-dimensional structures is reported. P-TENGs have the potential to be used in many practical applications, including self-powered sensing devices, human–machine interaction, electrochemistry, and highly efficient energy harvesting devices. This leads to a simple yet effective way for the next generation of energy devices and paper electronics.

Research by the paper industry into new materials to expand the raw material base for pulp is on the ascendancy due to growing demand for pulp and paper products. This study assessed the anatomical...

In traditional deinking process, large amounts of chemicals are required which makes these methods expensive and polluting. Also, application of sustainable material implies the use of green processes to reduce waste and pollution. Green enzymatic deinking processes are alternatives to those technologies that have negative effects on the environment. In this work, we applied response surface methodology for deinking the electrophotography-printed paper based on a systematic experimental pattern. The individual and interactive effects of enzymatic deinking parameters including time, temperature, and enzyme dosage on the handsheet properties were investigated. Different analyses were carried out to determine the best process conditions of enzymatic deinking to optimize the handsheet properties (i.e., tensile, burst, whiteness, and brightness). The obtained responses of an oven-dried fiber at 45 min, 43 °C and the enzyme concentration of 1 mg/15 g were 12.44, 0.65, 72.20, and 87 for tensile strength, burst strength, whiteness, and brightness, respectively. Measuring the optical density of the deinked handset after printing showed that the printability of the deinked paper is in the desired range.

Cellulose triacetate (CTA) forward osmosis (FO) membrane from Hydration Technology Innovation (HTI), USA was tested in a locally fabricated FO system to concentrate synthetic and pulp and paper mill wastewater. The industry is among the 17 most polluted industries with intensive water consumption and wastewater generation (MoEFCC, Government of India). The CTA membrane was studied with deionized water as feed solution and 1 M NaCl as draw solution, which resulted into water flux of 5.8 L/m2h and reverse salt flux of 0.2 g/L. A concentration stepping method was used to determine the critical draw concentration with lignin solution as the model feed. There was no deviation in flux between the baseline (deionized water feed) and the lignin solution up to 1.5 M NaCl, but a marginal deviation (8% and 21% respectively at 2 M and 3 M) was seen thereafter. The average water flux after 24 h FO study with synthetic wastewater as feed solution (draw solution 2 M NaCl) was 8 L/m2h, and 80% water recovery. Similar study with pulp and paper wastewater as feed solution (draw solution of 1.5 M NaCl) was 5.4 L/m2h was with 62% water recovery. Lignin and COD rejection in pulp and paper mill wastewater was 90% and 64% respectively. The preliminary results indicate that FO is promising for water and lignin recovery from waste streams.

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the ‘zero’ cost and the reliable supply of sludge raw materials producing 2 mol H2/mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen.

Virgin pulp is made by splitting up cellulose fibers from the woods by mechanical and chemical process without adding any recycled pulp content. The demand for trees, which are the basic raw material for making virgin pulp, increasing constantly in enormously growing paper manufacturing industry. The paper, which is made from virgin pulp is called as virgin paper and this is considered as better quality paper than the recycled paper. Now there is a need to increase the quality of recycled paper to equalize the quality of virgin paper, to reduce the demand for trees to make virgin pulp. In recycling, dispersive system is responsible for the de-inking process, which is one of the pulp purifying process which removes the printing ink from fibers. Chemicals are added in this deinking process which causes a serious problem by increasing the chemical concentration level of industrial outlet water. In conventional deinking technology, dispersive system is controlled by DCS which is quite complicated to control complex loop of operations. To overcome these problems, the dispersive system operations are controlled by PLC along with sensors which make the process easier and replacing the chemicals with enzymes will reduce the chemical concentration level of industrial outlet water and increases the quality of paper.

Cellulose bromo-isobutyl ester was prepared using filter paper as raw material through esterification reaction with 2-Bromoisobutyryl bromide (BIBB) in N, N-Dimethyl-formamide (DMF). Cellulose esters with different degree of substitution were obtained. FTIR result indicated the successful introduction of bromo isobutyryl group in cellulose to obtain cellulose ester (Cell-Br). The surface of modified filter paper become rough and grooves could be observed by SEM. The thermal stability of the cellulose ester decreased in comparison with unmodified filter paper. Besides, the hydrophobicity of the filter paper was improved and the water contact angle increased from 73.4° to 116.5° with increasing degree of substitution. The water vapor barrier property was improved by 26 %. Furthermore, it was also found the modified filter paper possessed antibacterial activity against S. aureus bacteria. The modified filter paper obtained could be potentially used in food packaging fields and the results provide a simple method to prepare functional filter paper.

Rising socioeconomic level and increasing popularity of e-commerce have dramatically increased the use of cardboard packaging materials, and consequent related recycling and wastes. Large amounts of sludge (up to 40% of input mass) is formed through the recycling process, with sludge solids that are very rich in cellulose fibers (~ 75% w/w). To date this sludge is mostly disposed in landfills, resulting in added economic and environmental costs to the recycling process. Short ozonation pretreatment of RPS resulted in enzymatic release of ~ 34% of the cellulosic fraction of the sludge as sugar, and fermentation of these sugars by yeasts resulted in production of ~ 15 g/L ethanol. The solid remnants, were used as a bio-sorbent, efficiently removing dyes from textile wastewater. Recycled paper sludge waste was thus a good source for both energy and water-treatment applications, increasing sustainability and circular economy in the paper and cardboard recycling industry.

This study evaluates the use of fermentation to increase nutrient availability in pulp and paper bio-sludge (PPBS) as feed for black soldier fly larvae (BSFL). Rearing of BSFL on fermented PPBS was carried out in a climate chamber in order to assess nutrient availability and larvae survival and growth. The PPBS used came from a chemo-thermomechanical pulp/groundwood pulp mill. The PPBS was fermented at 35 °C and 55 °C, respectively, at initial pH of 10. The effects of sediment and liquid from fermented PPBS on larvae dry weight, survival rate until the prepupae stage, bioconversion, and reduction rate of PPBS were measured. The bioconversion of the liquids (4.1–6.6%) was substantially higher than for both the sediments and untreated PPBS (≤ 0.4%). The survival rate, on the other hand, was substantially lower (26.3–30.9 %) than for the sediments and untreated PPBS (49.5–52.6%). Neither the sediments nor the liquids had significant effects on the larvae weight or on the PPBS reduction rate. The sediments had no significant effect on the survival rate or the bioconversion. This study demonstrates that fermentation dissolves a part of the PPBS and that dissolved substances in the fermentation liquid readily convert to larvae biomass. However, the bulk of the lignocellulose is not dissolved, and most of PPBS nutrients remain unavailable for growth of the larvae. Further research should focus on improved pretreatment of PPBS to increase availability of nutrients and thereby improve the feasibility of BSFL as a recycling method for PPBS.

We report a paper-based photodetector made from mixed cation organic perovskite halide MA1–xFAxPbI3 (MA = methylammonium (CH3NH3); FA = formamidium CH(NH2)2). The detector shows a substantial photo...

Biodiesel, as a green fuel, acts as a potential candidate to supplement conventional fossil fuels. This research study targets green environment (using biodiesel) and clean environment (reduce wastewater) by producing biodiesel through oleaginous biomasses (Yarrowia lipolytica, Metschnikowia pulcherrima and Lipomyces starkeyi) grown on pulp and paper industrial wastewater. Batch culture studies were explored for the potential feedstock of the oleaginous organism by the synthesis of single cell oil and fatty acid methyl ester (FAME) yield. Response surface methodology (RSM) was used to design the optimal experimental matrix and identify the optimal process conditions that enhance the FAME yield. To determine the inherent characteristics of the growth of oleaginous biomasses on the industrial wastewater, a data-driven adaptive neuro-fuzzy inference system (ANFIS) is implemented. Y. lipolytica strain cultured shown high biomass concentration of 32.36 g/l with biomass productivity of 5.39 g/l/d was considered for further scale-up for the transesterification process. Results indicated that the maximum yield of 0.48 (g-biodiesel/g-lipid) was obtained under the 2.5 g of lipid dosage with 0.02 g/ml of catalyst concentration by constant stirring at 70 °C. The optimum conditions to achieve maximum FAME yield of 1.154 g/g was obtained at 2.485 g, 70.87 °C and 0.021 g/ml for lipid dosage, temperature and catalyst concentrations, respectively.

Achieving an efficient catalyst in the ATRP system with a simple design, preparation from available materials, and high recyclability is a significant challenging issue. To attain the goal, herein, we used chitosan (CS)-modified cellulose filter paper (FP) as a green support for the synthesis of dip catalyst. The preparation of this catalyst involved surface treatment of the FP strips by CS coating through a dipping method, which increased the affinity of the substrate for adsorbing copper ions in the next step. The Cu@CS-FP catalyst was prepared without the requirement of any ligands. The synthesized dip-catalyst, in the form of the strips, was employed for the first time in the ATRP reaction of methyl methacrylate to assay catalytic activity. Catalytic insertion/ removal (ON/OFF) experiments were carried out during the polymerization. A reasonable control over the molecular weight with high conversion (68%) and polydispersity index of 1.32 under mild reaction conditions were obtained. Significantly, because of the facile separation of the catalyst, the amount of copper that remained in the polymer was very low (2.7 ppm). Also, the recyclability of the catalyst was investigated for five runs. The conversion in the final run was 64% without a loss of catalyst efficiency.

The pulp and paper industry has significant sustainability implications and necessarily requires a careful consideration of direct and lower-tier suppliers for effective sustainable supply chain ma...

Aim of the present work was to deepen the knowledge on the effects of funori on cellulose fibers with particular attention paid to their consolidation. Compared to canvas, paper samples (untreated or artificially aged) show different fiber packaging and liquid-absorbing properties. Herein, we conducted observations of cellulose fibers by scanning electron microscopy (SEM) in order to evaluate the seaweed extraction method employed in this work, as well the consolidation action had on the fibers through multiple additions of the prepared solutions. Surface homogeneity and fiber stiffness observed by us increased over time and the fibers, initially frayed and disordered, were eventually incorporated into the purified funori after several solution additions accompanied also by a progressive occlusion of the pores. The achieved consolidation effect was confirmed by means of mechanical tests. Moreover, the method herein developed was slightly modified in view of the application of the funori solution to a cultural asset of historical and botanical interest, still scarcely studied. Electronic microscopy allowed us to evaluate the consolidation and gluing effect obtained through subsequent funori applications.

A paper-based membrane coated by graphitic carbon nitride (g-C3N4) is prepared via a dip-coating method and used as a separator for sodium metal batteries with merits of low cost and environment-friendliness. Introduction of g-C3N4 effectively improves the ionic conductivity and the structural stability of the separator. Compared with traditional polyethylene separators and Al2O3-coated separators, the g-C3N4-coated separators show better electrolyte wettability, thermal stability, and electrochemical stability. Therefore, Na||Na3V2(PO4)3 battery using the g-C3N4-coated separator exhibits better cycling stability and higher rate capability. These results prove that the g-C3N4-coated paper-based separator is expected to become the next generation of low-cost and high-safety separator in sodium metal batteries.

The present study illustrates the electrocoagulation remediation of paper mill wastewater for multiple response optimization. Multiple response optimization can be combined into one desirability function. All variables and responses varied for a unique global solution. The effect of basic electrocoagulation process variables pH (3–10), conductivity (3.15–10 mS/cm), electrode distance (1–2.5 cm) and current density (5–20 mA/cm2) on four response parameters such as chemical oxygen demand, color, total dissolved solids and total organic carbon has been analyzed experimentally and statistically. The global solution for these variables and responses obtained by software over a hundred design points. For unit desirability function variables conditions were pH 7.49, Conductivity 8.34 mS/cm, electrode distance 2.06 cm and current density 9.32 mA/cm2. In these global variable conditions, responses were observed to be COD 70.19%, Color 75.03%, TDS 70.69% and TOC 71.93%, respectively.

This study investigated the feasibility of utilizing paper sludge (PS) as feedstock in the production of composite boards that are lightweight, durable and environmentally friendly. PS samples were collected from recycled newsprint (RN), corrugated recycled (CR) and virgin pulp (VP) pulping mills in South Africa. The PS was dried and mixed with magnesium phosphate cement to produce boards in a central composite design. Three different fillers including fly ash, calcium carbonate and silica fume were also added to the mix as binder replacement. The PS was characterized before use, and the produced composite board was evaluated for mechanical and physical properties. The boards produced had medium to high density (0.52—1.12 g/cm3) that could be used for non-structural interior applications. The results showed that boards containing RN had the highest mean value for modulus of elasticity (MOE) of 769 MPa. The mean MOE for boards containing CR- and VP-PS was 357 and 411 MPa, respectively. Calcium carbonate had the best effect on the board properties. Techno-economic analysis was simulated for four different types of feedstock scenarios at different locations including a combined scenario. Sensitivity analysis revealed that decreased feedstock cost resulted in decreased minimum required selling price. The analysis also revealed that the combined scenario proved to be the most cost-effective and profitable option for the future.

PurposeThis study develops an integrated zero waste discharge planning approach for improving resource efficiency in a pulp-and-paper manufacturing firm.Design/methodology/approachThe objectives of this study are to (1) identify the environmental, technical and social metrics in resource efficiency; (2) utilize fuzzy multi-objective programming and the hybrid particle swarm optimization algorithm to solve the fuzzy problem; and (3) develop an assessment for resource efficiency improvement in an industrial case study.FindingsThe findings demonstrate the superiority of hybrid particle swarm optimization algorithm in generating optimal results for a pulp-and-paper manufacturing firm.Practical implicationsThe findings demonstrate the superiority of hybrid particle swarm optimization algorithm in generating optimal results for a pulp-and-paper manufacturing firm.Originality/valueResource efficiency is a multi-objective problem in an uncertain environment. In particular, zero waste discharge planning involves minimizing the total cost and maximizing the waste material recovery rate, wastewater reuse, and waste heat recovery.

Compared with a single chemical indicator, the use of multivariate chemical indicators in aging status assessment of transformer cellulose paper insulation can improve the reliability of the evaluation. In this study, a non-destructive method based on multivariate chemical indicators was proposed to evaluate the remaining life of cellulosic paper insulation. The selected chemical indicators closely related to the aging of the insulating paper were analyzed. Additionally, by applying the subjective and objective weighting method, the evaluation information of each indicator was fully extracted to obtain reasonable comprehensive evaluation weights. Besides, the comprehensive evaluation index of multivariate chemical indicators was obtained by using the technique for order preference by similarity to ideal solution method, which is consistent with the deterioration law of paper insulation. Then, the correlation lifespan model between the comprehensive evaluation index of multivariate chemical indicators and the degree of polymerization of insulating paper under different aging stages was established. The effectiveness of the proposed model was verified by experiments. This promising model can increase the accuracy of the condition assessment for the transformer cellulosic paper insulation.

Flexible paper-based sensors may be applied in numerous fields, but this requires addressing their limitations related to poor thermal and water resistance, which results in low service life. Herein, we report a paper-based composite sensor composed of carboxylic carbon nanotubes (CCNTs) and poly-m-phenyleneisophthalamide (PMIA), fabricated by a facile papermaking process. The CCNT/PMIA composite sensor exhibits an ability to detect pressures generated by various human movements, attributed to the sensor's conductive network and the characteristic "mud-brick" microstructure. The sensor exhibits the capability to monitor human motions, such as bending of finger joints and elbow joints, speaking, blinking, and smiling, as well as temperature variations in the range of 30-90 °C. Such a capability to sensitively detect pressure can be realized at different applied frequencies, gradient sagittas, and multiple twists with a short response time (104 ms) even after being soaked in water, acid, and alkali solutions. Moreover, the sensor demonstrates excellent mechanical properties and hence can be folded up to 6000 times without failure, can bear 5 kg of load without breaking, and can be cycled 2000 times without energy loss, providing a great possibility for a long sensing life. Additionally, the composite sensor shows exceptional Joule heating performance, which can reach 242 °C in less than 15 s even when powered by a low input voltage (25 V). From the perspective of industrialization, low-cost and large-scale roll-to-roll production of the paper-based sensor can be achieved, with a formed length of thousands of meters, showing great potential for future industrial applications as a wearable smart sensor for detecting pressure and temperature, with the capability of electric heating.

The plasmonic properties of gold nanoparticles (AuNPs) are a promising tool to develop sensing alternatives to traditional, enzyme-catalyzed reactions. The need for sensing alternatives, especially in underdeveloped areas of the world, has given rise to the application of nonenzymatic sensing approaches paired with cellulosic substrates to biochemical analysis. Herein, we present three individual, low-step, wet-chemistry, colorimetric assays for three target biomarkers, namely, glucose, uric acid, and free cholesterol, relevant in diabetes control and their translation into paper-based assays and microfluidic platforms for multiplexed analysis. For glucose determination, an in situ AuNPs synthesis approach was applied into the developed μPAD, giving semiquantitative measures in the physiologically relevant range. For uric acid and cholesterol determination, modified AuNPs were used to functionalize paper with a gold-on-paper approach with the optical properties changing based on different aggregation degrees and hydrophobic properties of particles dependent on analyte concentration. These paper-based assays show sensitivity ranges and limits of detection compatible for target analyte level determination and detection limits comparable to those of similar enzymatic, colorimetric systems, relying only on plasmonic transduction without the need for enzymatic activity or other chromogenic substrates. The resulting paper-based assays were integrated into a single 3D, multiplex paper-based device using paper microfluidics, showing the capability for performing different colorimetric assays with distinct requirements in terms of sample flow and sample uptake in test zones using a combination of both horizontal and vertical flows inside the same device. The presented device allows for multiparametric, colorimetric measures of different metabolite levels from a single complex sample matrix drop using digital color analysis, showing the potential for development of low-cost, low-complexity tools for diagnostics toward the point-of-care.

Gelatine sizing was used extensively for western papermaking before the nineteenth century and this technique is still applied nowadays for restoration purposes. Despite its wide use, the relationships between gelatine types, the strength of the size and its distribution inside the paper sheet are still unclear. Different concentrations of three gelatines of various origins and types (A/B) were used to size model papers. The gelatine uptake, the strength of the size and the presence of gelatine at the papers surface were investigated by using a water drop test method and ATR-FTIR spectroscopy. At a given concentration, similar uptakes were found for all gelatines but great variations were observed in terms of size strength and of gelatine ability to cover the surface of paper sheets. In addition, Scanning transmission X-ray microscopy was performed on paper fibres cross sections to map the distribution of the organic compounds (both cellulosic and proteinaceous) on a nanometer scale. This showed that gelatine coats but does not penetrate the fibres. It can be inferred that the different size strengths observed between the tested gelatines are mainly due to different ways of filling holes between fibres inside the paper mat, some gelatines being more prone to go inside the sheet than others which remain mostly distributed near the surface.

Loop-mediated isothermal amplification (LAMP) has been widely used to detect many infectious diseases. However, minor inconveniences during the steps of adding reaction ingredients and lack of simple color results hinder point-of-care detection. We therefore invented a fluorometric paper-based LAMP by incorporating LAMP reagents, including a biotinylated primer, onto a cellulose membrane paper, with a simple DNA fluorescent dye incubation that demonstrated rapid and accurate results parallel to quantitative polymerase chain reaction (qPCR) methods. This technology allows for instant paper strip detection of methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory and clinical samples. MRSA represents a major public health problem as it can cause infections in different parts of the human body and yet is resistant to commonly used antibiotics. In this study, we optimized LAMP reaction ingredients and incubation conditions following a central composite design (CCD) that yielded the shortest reaction time with high sensitivity. These CCD components and conditions were used to construct the paper-based LAMP reaction by immobilizing the biotinylated primer and the rest of the LAMP reagents to produce the ready-to-use MRSA diagnostic device. Our paper-based LAMP device could detect as low as 10 ag (equivalent to 1 copy) of the MRSA gene mecA within 36-43 min, was evaluated using both laboratory (individual cultures of MRSA and non-MRSA bacteria) and clinical blood samples to be 100% specific and sensitive compared to qPCR results, and had 35 day stability under 25 °C storage. Furthermore, the color readout allows for quantitation of MRSA copies. Hence, this device is applicable for point-of-care MRSA detection.

Natural cellulose paper is flame retarded using ammonium polyphosphate/montmorillonite (APP/MMT) nanocompound through coating method. Their morphologies are assessed by scanning electron microscopy, chemical components by energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, chemical structure by Fourier transform infrared, thermal stability by thermo-gravimetric analysis and fire retardancy by 45° horizontal burning test. The results show that the thermal stability and flame retardancy of coated paper samples are enhanced obviously, and all samples are self-extinguishing during the tests due to the char formation reaction between APP/MMT and cellulose. Then the treated paper, AM-18.3, as surface flame retardant treatment for low specific surface area (SSA) polypropylene (PP) specimens (PP@AM-18.3) also is investigated using cone calorimeter. Compared with two controlled samples, PP@AM-18.3 shows significantly increased time to ignition, the lowest fire growth index and highest fire performance index. This may give a new flame retarded approach for low SSA polymer materials with little amount flame retardants.

Herein, combined with a pervasive smartphone installed with a color recognition app, dual-responsive CDs@Eu/GMP ICPs were designed as a red-to-blue paper-based colorimetric sensor for the point-of-use analysis of cerebral acetylcholinesterase (AChE) upon Cd2+ exposure. Blue-emitting CDs with multi-functional groups as guests were encapsulated into the network of Eu/GMP ICPs to obtain CDs@Eu/GMP ICPs with the sensitized red fluorescence of Eu3+. With the presence of thiocholine (TCh), derived from acetylthiocholine (ATCh) hydrolyzed by AChE, the coordination environment of the CDs@Eu/GMP ICPs was interrupted, leading to the collapse of the CDs@Eu/GMP ICP network and the corresponding release of guest CDs into the surrounding environment. Consequently, the sensitized red fluorescence of Eu3+ decreased and the blue fluorescence of the CDs increased. This obvious red-to-blue fluorescent color changes of CDs@Eu/GMP ICPs on test paper could then be integrated with the smartphone for point-of-use analysis of cerebral AChE upon Cd2+ exposure, which not only offers a new analytical platform for a better understanding of the environmental risk of Alzheimer's Dementia (AD), but also holds great potential in the early diagnosis of AD even at the asymptomatic stage with the decrease in CSF AChE as an early biomarker.

Edible oils form an integral component in the human diet as well as in the industrial preparations. Any adulteration in oil is concerning from nutritional as well as economical perspective. Although analytical techniques exist for detection of adulterants in oil, most of them require sophisticated instruments, and trained professionals. Microfluidic based lab-on-a-chip technologies have rapidly progressed over the recent years and offer promising alternatives in this regard. In this work, we report development of a paper-based microfluidic lab-on-a-chip for detection of palm oil contamination in sunflower oil. We use the paper-based microfluidic colorimetric detection approach that indicates the presence of adulteration in a visual manner. The data is analyzed using digitally acquired images along with ultraviolet–visible spectrophotometry. The paper-based microfluidic device is fabricated and tested for 10–50% (v/v) palm oil adulteration in sunflower oil. Further, we employ the device for free fatty acid content tests in oil samples. Visual signal acquired from the device is optimized by varying phenolphthalein proportions. The stability of visual colorimetric signal is examined over time and is found to remain steady over the trial period of six days considered in this work. The integration of the detection device with smartphone imaging can prove to be useful for onsite data collection. We believe the approach presented here can be extended to food quality monitoring portable platforms.

There is a relative lack of research on the development of creepage discharge in aged oil-paper insulation subjected to AC-DC combined voltage in converter transformers. In this study, based on the physical and chemical properties of oil-paper, we propose a sphere-plate electrode model to study the creepage discharge parameters and characteristic spectra of aged oil-paper subjected to AC-DC combined voltage. The results show that the creepage discharge inception voltage of aged oil-paper is related to the AC voltage component of the AC-DC combined voltage. However, when the DC voltage component is 60 kV, the flashover phenomenon was found to occur in one of the severely aged samples before the AC voltage was applied. Despite being subjected to the same DC voltage, the flashover phenomenon did not occur in three other samples aged to different degrees. Large-amplitude discharges were found to appear earlier in the severely aged samples. At the same creepage discharge stage, as the aging time of the oil-paper increased, the number of large-amplitude discharges was found to rapidly increase, and the time interval between adjacent discharges was found to gradually decrease. At each stage of the creepage discharge, the small-amplitude discharge has a “hump” shaped distribution. The larger the DC voltage component, the shorter the endurance time of aged oil-paper, and the more severe the damage to the oil-paper. The DC voltage component was found to have an accelerating effect on the development of creepage discharge in aged oil-paper insulation.

Introduction We developed low-cost, portable paper-based diagnostic devices for detection of human immunoglobulin M (IgM) and immunoglobulin G (IgG) in serum without any sample preparation. These devices can be used to help identify presence of diseases, used to provide rapid results ( Materials and Methods We successfully accomplished colorimetric detection of human IgG and human IgM using a sandwich-style assay within the microfluidic paper device via vertical flow immunoassay configuration. The reaction zone in the wax printed paper layer is a small circular pattern. Gold nanoparticles conjugated with anti-human IgG and IgM antibodies have been used for colorimetric detection of IgG or IgM by naked eye. Colorimetric signal can be precisely quantified through implementation of image analysis software which can be developed as an app for a smartphone. The size of the device is 2 cm × 2 cm × 1 mm. Results Colorimetric detection of human IgG was accomplished at 100 fg/mL concentration using a gold nanoparticle–conjugated anti-human IgG antibody. The developed platform has a dynamic range of IgM and IgG concentrations between 0.1 pg/mL and 100 μg/mL. These devices provided a color readout in Conclusions Because of the inherent simplicity of the device operation and their ease of use, there is no variation between samples and users of the device. This low-cost approach enables multiplexing with >1 measurement performed in parallel at the same time. We anticipate that because of the sensitivity, specificity, ease of use, and overall reliability, this approach will become a standard for diagnosis of diseases and health conditions.

This work investigates the influence of blending waste paper and cement at fixed proportion with varying proportions of chicken feather fiber (CFF) and wood saw dust (WSD) as reinforcements. Samples produced were tested for flexural properties and water absorption potentials. The outcome showed that with increasing CFF content and reducing WSD content, water absorption reduced while flexural strength, modulus of ruptures (MOR) and modulus of elasticity (MOE) increases. MOR and MOE were at peaked when the ratio of CFF to WSD was 3:2 while flexural strength reached it crescendo at 4:1 of CFF to WSD. It was noticed that higher CCF content from 3 to 5 wt% gave better results in most of the investigated properties compared to WSD. Therefore, it was concluded that low quantity of WSD is needed to form a synergy with CFF in order to achieve optimum results. Well dispersed CFF-WSD phase in waste paper-cement based composites was observed to be responsible for the enhancement in the investigated properties.

Paper-based diagnostics are leading the field of low-cost, point of care analytical techniques. However, large scale testing facilities such as hospitals are still primarily using the gel column agglutination technique. This is because paper-based systems are single use tests that are generally more time consuming and less automatable than traditional methods. Here, we present a novel, rapid and scalable, paper-based blood typing method that can produce test results in under ten seconds. We believe this is the fastest blood typing test that is appropriate for large scale automation. The test consists of placing a drop of antibody solution on paper, followed by a drop of blood on the same locus, and measuring the evolution of blood stain area as a function of time. Positive reactions for both forward and reverse tests have significantly slower growth rates and smaller final stain sizes when compared to negatives. We analyse the effect paper type, red blood cell concentration, antibody specificity (A, B and D) and antibody dilution have on the sensitivity and reproducibility of the technique. A high sensitivity is found in papers with a low density and thickness. The optimum red blood cell concentration is determined from a balance between wicking rate, strength of reaction and optical contrast. A and B antibodies give more sensitive results than D; however, the D antigen can still be successfully identified. This technique has the potential to significantly cut down the time and cost of blood typing tests and enable design of a new high throughput and fully automatable system.

The present work describes a sensitive, simple, cost-effective and fast analytical procedure to detect the parabens in industrial waste effluent water samples using novel activated carbon nanofiber (CNF) modified filter paper based solid phase extraction technique coupled with liquid chromatography with photodiode array detector (UPLC-PDA). The carbon nanofiber coated filter paper was used as an adsorbent and also characterized by field emission scanning electron microscope (FESEM) showed superior porous structure. Various factors effecting the adsorption and desorption process were studied. The optimum parameters which improve the efficiency are paper length 1 cm × 2 cm, adsorption time 15 min, eluent methanol, eluent volume 5 mL, sample pH 7, desorption time 2 min, 2% salt addition and 300 rpm stirring rate respectively. The parabens exhibited superior linearity ranging from 0.1-50 ng mL-1. The regression coefficient (R2) value ranging from 0.9981-0.9989. This method exhibited good sensitivity with the quantification limit (LOQ) between 0.5-0.75 ng mL-1 and detection limit (LOD) over the range of 0.1-0.25 ng mL-1. The precision was expressed from the RSDs values from 0.74-0.97 %. The spiked analytes revealed excellent recoveries in the range of 95.30-116.72 % with RSD less than 5.72 % for all the water samples also applied for real samples.

Lab-on-paper, or microfluidic paper-based analytical devices (μPADs), use paper as a substrate material, and are patterned with a system of microchannels, reaction zones and sensing elements to perform analysis and detection. The sample transfer in such devices is performed by capillary action. As a result, external driving forces are not required, and hence the size and cost of the device are significantly reduced. Lab-on-paper devices have thus attracted significant attention for point-of-care medical diagnostic purposes in recent years, particularly in less-developed regions of the world lacking medical resources and infrastructures. This review discusses the major advances in lab-on-paper technology for blood analysis and diagnosis in the past five years. The review focuses particularly on the many clinical applications of lab-on-paper devices, including diabetes diagnosis, acute myocardial infarction (AMI) detection, kidney function diagnosis, liver function diagnosis, cholesterol and triglyceride (TG) analysis, sickle-cell disease (SCD) and phenylketonuria (PKU) analysis, virus analysis, C-reactive protein (CRP) analysis, blood ion analysis, cancer factor analysis, and drug analysis. The review commences by introducing the basic transmission principles, fabrication methods, structural characteristics, detection techniques, and sample pretreatment process of modern lab-on-paper devices. A comprehensive review of the most recent applications of lab-on-paper devices to the diagnosis of common human diseases using blood samples is then presented. The review concludes with a brief summary of the main challenges and opportunities facing the lab-on-paper technology field in the coming years.

Highly foldable and flexible energy materials are a requisite for actual applications in self-powered wearable electronics and complex environments. Unfortunately, thermoelectric (TE) materials showing excellent foldability and flexibility under external mechanical stresses have rarely been reported so far. Herein, foldable and flexible TE materials based on Chinese traditional Xuan paper (a bio-based material) and commercialized conducting polymer of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) are reported. With a facile dip-coating and subsequent drying process, PEDOT:PSS is wrapped on the surfaces of cellulose fibers of Xuan paper via hydrogen-bond interactions. The resulting composite films exhibit outstanding mechanical and decent TE properties. In particular, the PEDOT:PSS/Xuan paper composite films exhibit excellent foldability and flexibility, and can be easily processed into various shapes with no distinct damage to their electrical conductivity and TE performances. This work paves the way for imparting TE performance to insulating paper-based materials, and the unique foldability may widen the TE applications in complex and extreme environments.

Paper-based sensors open a new avenue to produce easy-to-handle, inexpensive and simple-use analytical devices for widespread application fields in biological systems involving diagnosis, drug discovery and biosensing. In this manuscript, we constructed a fluorescence sensor based on functionalized paper coupled with silver nanoparticles (AgNPs) etching for hydrogen peroxide (H2O2) determination in biological systems. A significant fluorescence signal was achieved by immobilizing CDs onto the surface of cellulose filter paper by covalent bonds. The CDs functionalized paper coupled with AgNPs composites platform (PCD/AgNPs) consisted of CDs functionalized paper (PCD) and a AgNPs layer which acted as a fluorescence quencher of CDs via a physical adsorption mechanism. With the introduction of H2O2, the AgNPs were etched accompanied by the fluorescence recovery. As the target, a good linear relationship of a fluorescence turn-on response toward H2O2 between 10 and 120 μM was obtained with a limit of detection of 1.38 μM in our sensor. The designed sensor demonstrated good specificity and would have broad application prospects in the detection of milk samples and determination of H2O2 released from cancer cells.

Detecting vascular endothelial growth factor C (VEGF-C), a kind of tumor biomarker, is of significant clinical importance in evaluating the prognosis of patients with cancer. However, laboratory analyses are usually not suitable for point-of-care testing because they are expensive and time consuming. In response to these challenges, we fabricated an origami paper-based microfluidic electrochemical device. To improve the specificity of VEGF-C detection, nanocomposites, synthesized by new methylene blue (NMB), amino-functional single-walled carbon nanotubes (NH2-SWCNTs), and gold nanoparticles (AuNPs), were used to modify the surface of working electrodes. Results of electrochemical detection showed that the immunosensor had excellent linearity, ranging from 0.01 to 100 ng mL−1 (R2 = 0.988), and the limit of detection was 10 pg mL−1. To confirm the high specificity of the device under real-world conditions, we evaluated the device using clinical serum samples from our hospital. The results demonstrated that the device had an excellent performance and could provide a platform for real-time detection of cancers., Sun, Wang et al. report an origami paper-based immunosensor for the electrochemical detection of the VEGF-C biomarker in blood serum. The immunosensor is made by modifying the surface of working electrodes with new methylene blue, amino-functional single-walled carbon nanotubes, and gold nanoparticles and demonstrates excellent performance with a limit of detection in the range of picograms per milliliter.

Leukocyte esterase (LE) is a useful marker that can be used in establishing a diagnosis of urinary tract infections (UTIs). The development of a UTI diagnostic method with quantitative determinations of biomarkers across all age groups is becoming more important. In this report, microfluidic resistance sensors based on silver ink (Ag ink) and silver ink mixed with ZnO nanoparticles (Ag-ZnO ink) were synthesized and coated on cellulose paper, namely LE-Ag-μPADs and LE-Ag-ZnO-μPADs, respectively, for the sensitive detection of LE. The microfluidic design increases the precision of data and further allows for quantitative determination and early detection of LE in human urine. The quantification of LE relies on the change in the resistance readout coating with Ag ink as well as Ag-ZnO ink in the detection zone. A mixture of 3-(N-tosyl-l-alaninyloxy)-5-phenylpyrrole (PE) and 1-diazo-2-naphthol-4-sulfonic acid (DAS) was deposited in the sample zone to selectively recognize LE, and the resulting nonconductive products, i.e., azo compounds, further reacted with the Ag ink and Ag-ZnO ink to increase resistance. The quantitative detectable LE concentrations between 2 to 32 (×5.2 U mL-1), i.e. ≈12 to 108 μg L-1, cover the commercial dipstick range of trace, +1 and +2. The minimum detectable concentration of LE in urine was 1 (×5.2 U mL-1). The lower concentrations of LE detectable by LE-Ag-μPADs (1-8 × 5.2 U mL-1) are below the value achieved with the ELISA LE kit. Urine samples from inpatients with indwelling urinary catheters were used, and the LE levels measured by the present device were highly correlated with those determined by a commercial urine analyser.

The paper corrugation tube is an innovative kind of energy absorbing structure and shock absorber which can play an important role on the cushioning energy absorption for airdrop equipments and transportation packaging. The deformation characteristics and failure modes of the regular triangle, quadrangle, pentagon and hexagon paper corrugation tubes were comparatively studied by a series of axial static compression experiments, the cushioning energy absorption was evaluated by the seven characteristic parameters (e.g. initial peak force, mean crush force, total energy absorption, specific energy absorption, crush force efficiency, unit area energy absorption and stroke efficiency), and the influences of tube direction, cross-sectional shape, tube length and compression rate on failure modes and cushioning energy absorption were analyzed and compared. These researches showed that the tubes along X direction only have the accordion deformation mode, yet the tubes along Y direction have four deformation modes including steady state progressive buckling, Euler buckling, angular tear and transverse shear. For the paper corrugation tubes along Y direction, the cross-sectional shape has obvious influence on the cushioning energy absorption of structures, and the specific energy absorption and unit area energy absorption of regular triangle and pentagon tubes are better than those of the tubes with regular quadrilateral and hexagonal cross-section at compression rates of 12 and 48mm/min. The tube length of 150 mm or compression rate of 72 mm/min would cause the increase of contribution proportion of non-ideal deformation mode and the decrease of cushioning properties. The paper corrugation tubes along X direction have more stable and controllable deformation mode, yet the paper corrugation tubes along Y direction have better cushioning energy absorption.

The waste of paper or the paper dump is a serious problem and its occurrence is widespread in various institutions. Wastepaper can be recycled to produce some important and usable products that are ecological and biodegradable. For example, it is used to extract new paper from the old by chemical decomposition. Other products such as paper plates, paper cups, paper spoons, tiles, toys, crafts, etc. can be formed from the slurry. This project also initiates a mould that makes cups and plates from the wastepaper management circuit. With learning institutions being the main consumers, most paper are usually eliminated after its use. The waste remains undeveloped and unused, although is a valuable resource. Studying the design of a manual, economical and efficient paper recycling machine, it can be surmised that the design uses the integration of the knowledge gained about the recycling technology that exists manually from the paper recycling machines used to form a cheap but effective paper recycling system. The advantages of the machine are not only of recycled paper, but also the advantages of the interaction of the manual drive system, which will also reduce the high cost. As the design is not 100% effective, the transmission, belt and chain transmission correspond to the estimated 90% efficiency using the 90% for the design. The power consumption for the design is 450 W and since an average user can produce 100 W constant, it takes 5 people to drive the machine.

Wastewater containing heavy metal ions is considered as the serious environmental problem in human society. Adsorption as the widely used method plays an important role in wastewater treatment, which is based on the physical interaction between metal ions and sorbents. Drumsticks are reported to have efficient adsorbing property. It has been found that Moringa causes alteration in testosterone levels, preventing testicular damage and hence is capable of protecting against the toxic effect of hazardous material. Based on this phenomenon of adsorption by Moringa species, we are trying to remove heavy metals from aqueous sample. The bio sorption of heavy metals by non-living biomass of plant origin is an innovative and alternative technology for the removal of the pollutants from aqueous solution and offers several advantages such as low-cost bio sorbents, high efficiency, minimization of chemical and/or biological sludge, and regeneration of the bio sorbent. Moringa oleifera (drumsticks) has a number of advantages including low cost, biodegradable sludge production and lower sludge volume, and also it does not affect the pH of the water. Apart from turbidity removal, Moringa oleifera seeds also possess antimicrobial properties. Amount of adsorption is considerably larger when activated charcoal is used. Thus, this work reports preparation of activated charcoal from drumsticks seeds and fibres. These are generally part of kitchen waste; thus, its preparation and utilisation for heavy metal toxicity not only controls water pollution but also help in reduction of kitchen waste. It will serve as an effective, cheap and robust and green tool for toxicity control. The paper reports the removal of heavy metal (Pb, Ni, Cd, As in this study) by application of prepared activated charcoal tablets via MATLAB assisted paper based sensors. These tablets will surely serve as point-of- care devices for removal of heavy metal toxicity.

We report a simple and cost-effective paper-based and colorimetric dual-mode detection of As(iii) and Pb(ii) based on glucose-functionalized gold nanoparticles under optimized conditions. The paper-based detection of As(iii) and Pb(ii) is based on the change in the signal intensity of AuNPs/Glu fabricated on a paper substrate after the deposition of the analyte using a smartphone, followed by processing with the ImageJ software. The colorimetric method is based on the change in the color and the red shift of the localized surface plasmon resonance (LSPR) absorption band of AuNPs/Glu in the region of 200-800 nm. The red shift (Δ

In recent years there has been increasing interest in the use of recycled paper waste in the production of concrete to reduce environmental pollution. This study aims to investigate the use of raw paper waste to produce lightweight cement mortar and to study the effect of the aluminium sulphate treatment of raw paper waste on the compressive strength, absorption ratio and hardened density of mortar. This study used raw paper waste as a replacement for fine aggregate, with percentages of 5%, 10%, 15%, 20% and 30%. The same percentages were examined for the aluminium-sulphate-treated paper waste. The study aims to achieve a similar workability and fixed flow rate for all mixes; therefore, the water–cement ratios were changed for mixes containing paper waste to balance the water absorbed by the paper waste. The study found that the treatment of paper waste with aluminium sulphate helps to reduce the amount of water absorbed by the paper waste and also reduces the amount of water required to maintain its workability, with a higher paper-waste content requiring a larger water content to achieve a similar workability. It was found that the higher the paper-waste content, the lower the wet and dry densities. The compressive strength at both an early and mature age decreased with the increased content of paper waste. Finally, the treatment of paper waste with aluminium sulphate increases the early age compressive strength for similar replacement percentages of up to 19%.

Cyanide ( CN - ) is a deleterious chemical and can cause serious health effects upon exposure even at low concentrations. Different sensors have been developed to monitor cyanide in water, which, however, suffers from complex mechanisms and high-cost. Curcuma longa or turmeric is a commercially available natural dye (usually in powder form) used as medicine. The phenolic substance curcumin is responsible for its yellow color and is capable of sensing environmentally significant analytes such as CN - . In this study, a colorimetric sensor for cyanide in aqueous solution was fabricated by the immobilization of crude curcumin on ordinary filter paper. The curcumin was extracted from locally available turmeric powder using a simple extraction method. Its successful integration in the filter paper was validated by FT-IR spectroscopy. UV–Vis analysis showed that the curcumin-based paper sensor was sensitive to CN - (down to 5.0 ppm), producing a visual change from yellow to dark red. The fabricated sensor also demonstrated high selectivity towards CN - in the presence of N a + , K + , and F - . Its response time was found to be inversely proportional to the concentration of the CN - in the solution. Assessment of reusability revealed that the sensor was reusable for up 8 cycles before significant changes in colorimetric response were observed. Importantly, the fabricated sensor exhibited applicability for actual cyanide monitoring in real water samples.

Infectious diseases cause millions of deaths annually in the developing world. Recently, microfluidic paper-based analytical devices (μPADs) have been developed to diagnose such diseases, as these tests are low cost, biocompatible, and simple to fabricate. However, current μPADs are difficult to use in resource-limited areas due to their reliance on external instrumentation to measure and analyze the test results. In this work, we propose an electricity and external instrumentation-free μPAD sensor based on the colorimetric enzyme-linked immunosorbent assay (ELISA) for the diagnosis of infectious disease (3D-tPADs). Designed based on the principle of origami, the proposed μPAD enables the sequential steps of the colorimetric ELISA test to be completed in just ∼10 min. In addition, in order to obtain an accurate ELISA result without using any instrument, we have integrated an electricity-free "timer" within the μPAD that can be controlled by the buffer viscosity and fluid path volume to indicate the appropriate times for washing and color development steps, which can avoid false positive or false negative results caused by an extended or shortened amount of washing and development times. Due to the low background noise and high positive signal intensity of the μPAD, positive and negative detection results can be distinguished by just the naked eye. Furthermore, the ELISA result can be semi-quantified by comparing the results shown on the μPAD with a color chart diagram with a detection limit of HIV type 1(HIV-1) p24 antigen as low as 0.03 ng mL-1. These results demonstrate the proposed sensor can perform infectious disease diagnosis without external instrumentation or electricity, extending the application of the μPAD test for on-site detection and use in resource-limited settings.

Woody and agricultural wastes are important fuels in many countries, and have the potential of being even more important in the future. The main problems of plant biomass combustion are low ash melting temperatures and increased emissions. The most widely used treatment to solve the problem of low ash melting point is blending a fuel with an additive. In this work, pellets were produced from wheat straw containing wood sawdust and paper sludge in the following proportions 40:40:20 and 45:45:10 (straw/sawdust/paper sludge). The purpose of this work was to study the influence of sludge and dendromass on the straw pellet parameters and combustion process. The highest calorific value of 15.71 MJ kg&minus, 1 was registered for a sample with a 10% paper sludge concentration. The effectiveness of paper sludge was proved, and the ash melting temperature was increased from 1025 to 1328 &deg, C for the same sample.

Coatings based on pigment and polymer binders are applied on paper surfaces to improve their surface, optical, and printing properties. Besides the coating composition, the structure and properties of the coated papers are influenced by the coating layer consolidation upon drying. In this study, the influence of drying conditions on the structure and properties of coating layers based on natural pigments (clay) and polymer binders (butadiene acrylonitrile latex) has been analyzed. Using a laboratory rod Mayer device, the coatings were applied as thin layer (about 15&ndash, 16 g/m2) on the paper surface and samples of coated paper were dried at 20 and 105 &deg, C temperatures. The optical, structural, and water absorption properties of the coating layer were evaluated by the measurement of gloss, opacity, void fraction, light scattering, and contact angle. The obtained results highlighted that both the drying temperature and latex content in the coating color have a synergic effect on the coated paper quality.

Paper-based microfluidic devices are popular for their ability to automate multistep assays for chemical or biological sensing at a low cost, but the design of paper microfluidic networks has largely relied on experimental trial and error. A few mathematical models of flow through paper microfluidic devices have been developed and have succeeded in explaining experimental flow behavior. However, the reverse engineering problem of designing complex paper networks guided by appropriate mathematical models is largely unsolved. In this article, we demonstrate that a two-dimensional paper network (2DPN) designed to sequentially deliver three fluids to a test zone on the device can be computationally designed and experimentally implemented without experimental trial and error. This was accomplished by three new developments in modeling flow through paper networks: (i) coupling of the Richards equation of flow through porous media to the species transport equation, (ii) modeling flow through assemblies of multiple paper materials (test membrane and wicking pad), and (iii) incorporating limited-volume fluid sources. We demonstrate the application of this model in the optimal design of a paper-based signal-enhanced immunoassay for a malaria protein, PfHRP2. This work lays the foundation for the development of a computational design toolbox to aid in the design of paper microfluidic networks. ©

Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper (AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene (AP) and 1-pyrenebutyrat (PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness (∼69.67 ± 15.3 MJ m−3 in average), simultaneously with superior strength (close to 1 GPa), allowing an impressive specific penetration energy absorption (∼0.17 MJ kg−1) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., −COOH, at the edges of graphene platelets and −NH2 and −COOH of AP/PB are critical to the formation of hydrogen bonding network.

Neotame is an artificial sweetener with increasing consumption in recent years, excessive intake of it may bring potential health risk. In this work, a rapid method was developed to detect neotame in instant grain beverages, which was based on surface-enhanced Raman scattering (SERS) technique and filter paper-based silver nanoparticles (AgNPs@FP) substrates. The designed substrate exhibits good SERS activity with an enhancement factor of 105 because of the synergistic effect of the concentrated silver nanoparticles and filter paper. Meanwhile, the stability and repeatability of this fabricated substrate have been investigated with the relative standard deviation of 6.1%. In addition, it shows an excellent linear relationship (R 2 = 0.997) between the SERS signal and the logarithm concentration of neotame with a wide concentration range (0.05–5 g/kg) in the quantitative analysis. The limit of detection of neotame can be as low as 0.01 g/kg in instant grain beverages, which is below the maximum allowable addition level for neotame in instant grain beverages set in China (GB2760-2014, 0.16 g/kg). The proposed method has great potential for the identification and quantification of neotame in food safety applications with high sensitivity.

Food safety is always one of the most important issues for human being. With the variety of food, it is required to develop rapid, low-cost and convenient detection techniques for food safety. As a representative, paper-based detection techniques have developed rapidly from simple test papers to various microfluidic paper-based devices. The paper-based analytical devices combining paper platform with a variety of advanced analytical methods have shown great application prospects for rapid testing of food safety. In this review, the surface functionalization and modification of paper are introduced. Then, the construction and development of various detection techniques are discussed, including colorimetric analysis, fluorescent analysis, electrochemical analysis, surface enhanced Raman spectroscopic analysis, and multimethods on paper-based platforms for the application in rapid detection for food safety. Finally, the prospects and future challenges of rapid detection techniques in food safety are also discussed.

Water-activated paper-based batteries are expected to be low-cost disposable power sources for paper-based sensor applications. In this study, a disposable paper-based battery was developed. The battery used activated carbon powder loaded on a carbon sheet as the anode. The cathode was coated directly on a paper filter to fabricate an integrated proton exchange membrane cathode. Copper (II) chloride mixed with multiwalled carbon nanotube (CuCl2/CNT) was used as the cathode. Water was injected into the anode electrode to activate the battery. The maximum power density of 134. 6 μ W /cm2 was obtained with the anode loaded 17 mg cm−2 activated carbon powder. The power output of the battery is proportional to the amount of activated carbon loaded on the anode.

Recently, the interest in active packaging utilization has increased with population growth, food demand and new consumer trend like food delivery services. This new system, however, requires the use of additives to extend the food product quality and safety as well as in maintaining the shelf-life. This study was to prepare the antimicrobial paper from I. cylindrica coated anionic nanocellulose crosslinked cationic to create a system with the ability to actively control microbe growth in the packaging materials. The process involved pulping of I. cylindrica using semi-chemical and soda chemical method. The antimicrobial paper was prepared by printing the pulp suspension in 60 g/m2 grammage in mold followed by the spray of anionic nanocellulose and subsequent soaking of the paper in cationic solution. The results showed the I. cylindrica paper coated anionic nanocellulose crosslinked with H+ and Al3+ cations were successfully produced. The paper produced was also observed to have antimicrobial activity against Gram-negative of E. coli and S. typhi as well as Gram-positive of S. aureus and B. subtilis bacteria. Furthermore, the best coating method was found on antimicrobial paper coated anionic nanocellulose crosslinked Al3+ as evidenced by smoother and compact surface structure.