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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

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.

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.

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.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. The enhancement of fingermarks on thermal paper can be challenging due to background staining caused by polar solvents used in fingermark enhancement techniques such as ninhydrin. This study explored a commercial one-step superglue fuming process, Lumicyano™, and Vacuum Metal Deposition (VMD) to develop fingermarks on this substrate and overcome this issue. Different sequential treatments involving Lumicyano™ and a combination of VMD methods were investigated with varying degrees of success with some sequences being highly sensitive. The VMD processes, however, were observed to generally be more effective at enhancing marks, whereas Lumicyano™ provided little or no benefit on this paper type. The results indicate that Lumicyano™ is only beneficial as a pre-treatment when the entire sequence of gold/zinc and silver/zinc is taken to completion. The gold/zinc and silver/zinc VMD processes were optimised on five different thermal papers, and the optimised techniques were then directly compared to determine which was more successful on each thermal paper type as a single treatment.

Point-of-care (POC) detection is crucial in clinical diagnosis in order to provide timely and specific treatment. Combining polyamidoamine (PAMAM) dendrimer, p-phenylene diisothiocyanate (PDITC) and superparamagnetic beads, a novel method to activate the surface of filter paper to bind DNA molecules has been developed. The method is based on the primary amination of the filter paper surface with PAMAM dendrimer, followed by generation of isothiocyanate groups via PDITC, and subsequent repetition of these two steps. Different parameters of the process have been optimized, including probe printing, preparation of target DNAs and detection. The result shows that, due to the highly porous structure of filter paper, high amounts of printed probes, target DNAs and magnetic beads can provide high signal intensities in the detection area via probe/target duplex formation. This method is suitable for rapid, specific and cost-efficient DNA detection on cellulose filter paper. It can be used as a POC device, in particular for diagnosis and treatment management of infectious diseases and identification of antimicrobial drug resistance genes.

A novel all-in-one paper-based sampling concept for mass spectrometric bottom-up protein analysis is here demonstrated in a chip format integrating instant immunocapture, protein reduction, - alkylation and tryptic digestion all in-device. Conventional laboratory grade filter paper was coated with the polymer 2-hydroxyethyl methacrylate-co-2-vinyl-4,4-dimethyl azlactone (pHEMA-VDM) with a subsequent covalent immobilization of the monoclonal antibody E27 targeting the biomarker human chorionic gonadotropin (hCG). In-device protein reduction and alkylation was optimized with regards to reagent concentration and reaction pH. The sampling concept showed a high degree of performance between 10 and 1000 ng/mL (R2 > 0.99) by a five-point calibration curve sampled with hCG spiked to human serum samples and freshly collected whole blood samples, respectively. LOD (experimentally obtained at 100 pg/mL (2.64 pM/0.9 IU/L)) was demonstrated to be up to ten times lower with more than six times faster sample preparation than what has previously been reported for on-paper analysis of hCG in human serum samples.

Photocatalytic materials have been widely used to remove dyes from printing and dyeing wastewater. However, difficulty in recycling of photocatalysts is the great concern in the real catalytic applications, which significantly raises the application cost. This study developed a low-cost catalyst by loading magnetic Ni onto filter paper (FP) via an easy going in-situ reaction. The characterization results displayed that the Ni particles were uniformly anchored onto the FP. The Ni@FP material presented a strong magnetic ability which was evidenced by a saturation magnetization (Ms) of 5.014 emu·g−1, a remanent magnetization (Mr) of 2.067 emu·g−1 and a coercivity (Hc) of 133.868 Oe. Meanwhile, the magnetic Ni@FP material displayed a recyclable advantage in photocatalytic degradation of methyl orange (MO) via an external magnetic field. There existed an optimal photocatalytic degradation rate of 93.40% within 5 min when MO concentration was 15 mg·L−1 at pH 8.0. Three cycle experiments confirmed that the Ni@FP possessed a satisfied stability and recycling ability. Moreover, the Ni@FP material presented a strong antibacterial activity which can prevent it from being contaminated by microorganisms. The versatility of the newly proposed photocatalyst in this study demonstrated its great application prospect in dyeing wastewater treatment.

Made available in DSpace on 2021-06-25T10:45:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-25 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Lactose (LAC) is a disaccharide - major sugar, present in milk and dairy products. LAC content is an important indicator of milk quality and abnormalities in food industries, as well as in human and animal health. The present study reports the development of an innovative imprinted voltammetric sensor for sensitive detection of LAC. The sensor was constructed using electropolymerized pyrrole (Py) molecularly imprinted polymer (MIP) on graphite paper electrode (PE). The MIP film was constructed through the electrosynthesis of polypyrrole (PPy) in the presence of LAC (template molecule) on PE (PPy/PE). To optimize the detection conditions, several factors affecting the PPy/PE sensor performance were assessed by multivariate methods (Plackett–Burman design and central composite design). Under optimized conditions, the proposed analytical method was applied for LAC detection in whole and LAC-free milks, where it demonstrated high sensitivity and selectivity, with two dynamic linear ranges of concentration (1.0–10 nmol L−1 and 25–125 nmol L−1) and a detection limit of 0.88 nmol L−1. The MIP sensor showed selective molecular recognition for LAC in the presence of structurally related molecules. The proposed PPy/PE sensor exhibited good stability, as well as excellent reproducibility and repeatability. Based on the results obtained, the PPy/PE is found to be highly promising for sensitive detection of LAC. Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Institute of Exact and Natural Sciences of Pontal Federal University of Uberlandia, 1600 20 St., Ituiutaba, Minas Gerais State Bioenergy Research Institute (IPBEN) São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Analytical Chemistry Department Institute of Chemistry São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State Bioenergy Research Institute (IPBEN) São Paulo State University (UNESP), 55 Prof. Francisco Degni St., São Paulo State FAPESP: 2017/25329–6 FAPESP: 2018/12131–6 FAPESP: 2019/13818–8 CNPq: 408783/2018–4 CNPq: 443315/2014–0 CNPq: 447668/2014–5 CAPES: 88887.368610/2019–00 FAPEMIG: APQ-02078-15 FAPEMIG: APQ-02905-15

There is growing demand for simple to operate, sensitive, on-site quantitative assays to investigate concentrations of drug molecules in pharmaceutical preparations for quality assurance. Here, we report on the development of two colorimetric analysis methods for the study the antibiotic doxycycline hyclate (DOX) and the nasal decongestant oxymetazoline hydrochloride (OXY), in solution as well as in their respective formulations. We compare a UV/vis spectrophotometry method with a color change recorded on a microfluidic paper-based analytical device (μPAD). Detection is based on the pharmaceutical compounds coupling with diazotized 4-aminoacetophenone (DAAP) under alkaline conditions to produce colored azo-dye products. These azo-compounds were monitored by absorbance at 425 nm for DOX and 521 nm for OXY, with linear calibration graphs in the concentration range of 0.5–35 mg L−1 (DOX) and 1.0–40 mg L−1 (OXY) and limits of detection of 0.24 mg L−1 (DOX) and 0.32 mg L−1 (OXY). For the μPAD method, color intensity was measured from photographs and a linear increase was observed at concentrations from above approximately 15 mg L−1 for both compounds and up to 35 mg L−1 for DOX and 40 mg L−1 for OXY. The developed methods were also applied to the formulated pharmaceuticals and no interference was found from the excipient. Thus, the paper-based device provides an inexpensive, simple alternative approach for use outside centralized laboratories with semi-quantitative capability.

The growing need for reliable analytical tools to perform measurements at the point-of-need has prompted the development of novel sensors that are low cost, portable, sensitive, easy to use, and capable of multiplexed analysis. Miniaturization of the sensors into microfluidic platforms has become a promising approach to achieve these self-contained sensors. However, traditional microfluidics often require relatively expensive and complicated pumping mechanisms that increase the cost and limit the portability of the sensors. From a material perspective, paper is an attractive substrate for constructing point-of-need sensors because of its affordability, vast availability, and self-pumping ability, particularly when combined with electrochemical detection. In this mini-review, we discuss various strategies to achieve multiplexing or simultaneous detection of multiple analytes in electrochemical paper-based devices and provide a brief guide on selecting the detection strategy based on the electrochemical property of the analytes.

A novel nacre-like flame-retardant paper based on graphene oxide (GO), and phytic acid (PTA) is fabricated via evaporation-induced self-assembly. This facile method is time saving and low energy consuming. A facile approach is proposed to improve thermal oxidative stability of GO paper by in situ phosphorus doping during flame exposure. Then fire-alarm system is designed based on the high-temperature thermal reduction characteristic of GO. The GO paper functionalized with PTA (GO-PTA) can provide ultrasensitive, reliable and longtime fire early-warning signal. Fire alarm can be triggered at approximately 0.50 s when GO-PTA samples are attacked by fire. Phosphorus atoms are in situ doped into graphene layers during fire exposure, endowing GO-PTA paper with outstanding thermal oxidative stability, and thus alarm duration time of GO is greatly improved. The work develops advanced fire detection and early-warning sensors that provide reliable and continuous signals, which provide more available time for fire evacuation.

Simultaneous enhancement in water flux and removal efficiency during the filtration process remains a big challenge for separation membranes. The porous structure of the filter paper can provide many channels for water transportation, but the separation performance is generally poor. The purpose of this study is to develop a new kind of filter paper consisting of ultralong hydroxyapatite (HAP) nanowires, cellulose fibers (CFs) and double metal oxide (LDO) nanosheets, and to achieve the simultaneous enhancement of both water flux and removal efficiency for high-performance dye separation. In this work, a novel kind of LDO/HAP/CF nanocomposite filter paper consisting of ultralong HAP nanowires and CFs and LDO nanosheets has been developed for rapid water filtration and highly efficient dye adsorption. Positively charged LDO nanosheets can adsorb on the surface of negatively charged ultralong HAP nanowires and embed in the porous networked structure of the LDO/HAP/CF nanocomposite filter paper, which can provide a porous structure for rapid water transportation and can adjust the pore size of the nanocomposite filter paper. As a result, the pure water flux of the LDO/HAP/CF nanocomposite filter paper can be adjusted. The optimized pure water flux of the LDO/HAP/CF nanocomposite filter paper can reach 783.6 L m-2 h-1 bar-1, which is 1.51 times that of the HAP/CF filter paper without LDO nanosheets (518.6 L m-2 h-1 bar-1). More importantly, the adsorption capacity of LDO nanosheets is high for dye molecules, the rejection percentage of Congo red (CR) by the as-prepared HAP/CF filter paper is only 59.8%, and its water flux is 534.7 L m-2 h-1 bar-1. The optimized rejection percentage and water flux of the LDO/HAP/CF nanocomposite filter paper for CR are significantly enhanced (98.3% and 736.8 L m-2 h-1 bar-1, respectively) compared to those of the HAP/CF filter paper. The size of LDO nanosheets has a significant effect on the water flux and dye rejection percentage of the LDO/HAP/CF nanocomposite filter paper. The as-prepared LDO/HAP/CF nanocomposite filter paper is promising for the applications in highly efficient purification of wastewater containing dye molecules.

Filter paper, as a widely used and low-cost lab consumable, can serve as template for the synthesis of one-dimensional (1D) materials since it is composed of 1D cellulosic fiber. In this work, 1D NiO/NiCo2O4 composite was simply fabricated by adsorption of Ni and Co acetate on the filter paper and subsequent calcination process. The precursors were obtained without further treatment to filter paper or chemical reaction between metal salts. Calcination process leads to the removal of template and formation of binary NiO/NiCo2O4 composite. Electromagnetic (EM) wave absorption performance of NiO/NiCo2O4 composite could be tuned by adjusting the calcination temperatures and dosage of metal salts. For the optimized absorber (calcination temperature of 600 °C and dosage of Ni and Co acetate with 2 mmol and 4 mmol), a wide absorption bandwidth of 6.08 GHz could be achieved with thickness of 1.88 mm and minimum reflection loss value was up to −57.4 dB by changing the thickness. The facile synthetic route may also inspire the preparation of other high-performance one-dimensional EM wave absorbing materials.

The dissemination of emerging electronic devices increases considerably alongside with the Internet of Things (IoT) paradigm. Some key elements considered in these devices (e.g. rare-earth) are becoming critical materials and are associated with serious environmental concerns. Therefore, there is a major requirement for designing differently our electronic technologies at the early stages of the research process. Many reports present the promising properties of paper-based electronics as meant to address this challenge. Through technical and life cycle assessments, this article discusses the main design levers in terms of material and fabrication process choices for the eco-design of paper-electronics water quality sensors. Our results suggest conscientious choices of conductive nanomaterials and additive fabrication techniques.

Herein we report the first two distance-based microfluidic paper-based analytical devices (μPADs) using fluorescence to quantify aluminum. In addition to their read-by-eye quantification, the devices are simple to fabricate, require no sample pretreatment or preconcentration, and have a shelf life of >5 months. The first device is designed in a “chemometer” format where the length of a fluorescent band linearly responds to an Al(III) concentration. The second device uses a radial design where the fluorescent diameter also linearly responds to an Al(III) concentration. The chemometer device has a detection limit of 2.5 ppm (100 μM) and a linear range from 2 to 54 ppm Al(III) (100 μM–1 mM), R2 = 0.989). The radial device has a detection limit of 0.9 ppm (33 μM) and a linear range from 2 to 24 ppm Al(III) (100–900 μM, R2 = 0.968). The utility of the μPADs were successfully demonstrated by measuring Al(III) in two water effluent samples from the Gold King Mine near Silverton, CO.

Rising concern about the use of non-permitted colourants, in common food items such as dals and green vegetables sold in Indian markets, have led to a demand for low-cost point-of-use chemical analysis tools. Conventional food-analysis techniques involving tedious sample preparation protocols are not suited for in-field applications. Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique that is well-suited for point-of-use chemical analysis with molecular level detection capability, which can also serve as a quality assurance tool for businesses. Effective and rapid signal collection from a large-area sample within a field-setting using disposable, low-cost SERS substrates is a key challenge in implementing such a solution. Herein, we demonstrate the use of inkjet-printed thin films comprising of robust nanostructured-silver as flexible, paper-based SERS (P-SERS) swabs for the direct detection of Metanil Yellow (MY) from toor dal (yellow split pigeon peas) samples and Malachite Green (MG) from green peas and green chillies. The macroscopic uniformity of these thin-films in combination with a portable Raman spectrometer equipped with orbital raster scanning (ORS™) technology for signal collection results in an unprecedented precision (RSD ∼ 1.6%) upon characterizing samples saturated with Rhodamine-6G (R6G), a standard Raman probe. As several food-cleansing products have appeared in the marketplace, the adulterant removal efficacy of some commercially available ‘washes’ as well as products such as ‘ozoniser’, which was determined by SERS characterization of swabs before and after use, is also reported.

Inorganic salt modified paper substrates were developed and utilized in microfluidic paper based sampling coupled with potentiometric ion sensors for the determination of heavy metals, such as Cd2+ and Pb2+. The application of paper based sampling without any paper substrate pre-treatment were characterized with super Nernstian response, while the paper substrates with inorganic salt pre-treatment were characterized with standard Nernstian response. The application of inorganic salt modified paper substrates was found advantageous when the cation of the salt in the conditioning solution was the same as the primary cations of the ion-selective electrodes (ISEs). A relatively high concentration of inorganic salts during pre-treatment of the paper substrates, namely Cd(NO3)2 or Pb(NO3)2 with subsequent measurement of cadmium(II) and lead(II), by Cd2+- and Pb2+-ISEs, respectively was needed to sustain Nernstian response of sensors. It was also found that paper substrates facilitate sorption of metal ions onto the paper substrates, with stronger binding strength given to Pb2+ over Cd2+. Moreover, the metal-paper interactions suggest concentration dependent sorption-desorption of metal ion, which can have direct limitations of the use of paper based analytics for the determination of low analyte concentration of heavy metals. Nanyang Technological University The authors would like to thank NTU-India Connect Research Internship Program for financial support of Ms Tharini Saravana Sundaram from Coimbatore Institute of Technology, India.

Made available in DSpace on 2019-10-06T17:04:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Development and application of a new, simple, inexpensive, and eco-friendly method is presented for the quantification of bumetanide in human urine samples for the detection of doping in sports. The method involves the use of a paper platform and digital image detection and is based on the reaction between bumetanide, p-dimethylaminocinnamaldehyde (p-DAC), and HCl in a methanolic medium, yielding a colored compound in a delimited area on a qualitative filter paper. The concentrations of p-DAC and HCl were optimized by a chemometric experimental design. After the addition of the reagents to the paper, digital images were obtained by scanning in a multifunctional printer and analyzed using the RGB pattern. The linear bumetanide concentration range was 6.90 × 10 −5 –1.37 × 10 −3 mol L −1 with R 2 = 0.993 and the limits of detection (LOD) and quantification (LOQ) were 3.60 × 10 −4 and 1.09 × 10 −4 mol L −1 , respectively. A SPE clean-up step for the samples were required to eliminate the interference of urinary urea. The recoveries obtained varied from 94% to 105%, indicating the absence of significant matrix effects or interferences in urine samples after clean-up step. The proposed method was successfully applied to the analysis of bumetanide in human urine samples. Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: 001 FAPESP: 2015/21733-1

This paper describes the development of two microfluidic paper-based analytical devices (μPADs), one well-based and the other based on a lateral flow assay (LFA) configuration, to detect glucose via a colorimetric assay using the solid metal-organic framework (MOF) Zr-PCN-222(Fe), to encapsulate glucose oxidase (GOx). The well-based platform consisted of laminate sheets and multiple layers of wax-printed chromatography paper. Solutions of KI and glucose placed into the well flowed through the device and reacted with the GOx@MOF species sandwiched between the paper layers realizing a yellow-brown color. The LFA platform consisted of chromatography paper between parafilm and polyvinyl acetate (PVA) layers. GOx@MOFs spotted on the paper subjected to solutions of KI and glucose yielded a brown color. The devices were then dried, scanned, and analyzed yielding a correlation between average inverse yellow intensity and glucose concentrations. The development of these devices employing MOFs as biomimetic catalysts should further expand the applications of microfluidic technologies for sensors a variety of analytes.

Pulp and paper mill industry is already known as an extensive water user and hence produces large volume of wastewater. Phytoremediation has merits to offer due to its environmentally friendly, relatively low cost and easy maintenance. This work focused on the performance of a continuous pilot subsurface flow (SSF) system of constructed wetlands in removing chemical oxygen demand (COD) representing organic carbon, colour and suspended solids from recycled pulp and paper mill under 5-day hydraulic retention time (HRT) for 95 days. In this study, there were two tanks based on the SSF system; one tank planted with Malaysian native bulrush (Scirpus grossus) and another tank without plants acting as a control. It was found that the SSF system with S. grossus was much better compared to the SSF control. Throughout the 95-day exposure, the planted SSF system have achieved removals of 66.1, 55.8 and 87.2% for COD, colour and suspended solid (SS), respectively. However, the control SSF system without plants has lower performance for all the three parameters (62.4% COD, 44.4% colour and 84.8% SS), giving evidence that constructed wetlands is an efficient technology to phytoremediate COD, colour and SS from recycled pulp and paper effluent.

Bisphenol A (BPA), a well-known endocrine disruptor, is used as a color developer in thermal paper. More recently, some emerging structural analogues have been introduced to replace BPA due to the strengthened regulations concerning thermal paper. Nevertheless, very limited data are available regarding their occurrence and potential health risks. Here, thirteen potentially toxic compounds were investigated in paper products (120 thermal papers and 81 nonthermal papers) collected in Beijing, China. The results indicated that the replacement of BPA by alternatives such as Bisphenol S (BPS), Bis(2-chloroethyl)ether-4,4″-dihydroxydiphenyl sulfone copolymer (D-90), 4-hydroxyphenyl 4-isoprooxyphenylsulfone (D-8), Bis(4-hydroxyphenyl)sulfonylphenyl (BPS-MAE) and Bis-(3-allyl-4-hydroxyphenyl) sulfone (TGSA) has been significantly advanced in several types of thermal paper (i.e., market weight stickers, train tickets, express labels, air boarding passes and lottery tickets). The mean value for the total analyte concentrations in thermal paper was 6.06 mg/g, and the highest level found was 26.0 mg/g. In addition, the frequent detection of these chemicals in nonthermal paper (>80%, n = 81) demonstrated that the contamination in thermal paper can be spread into other recycled paper, such as corrugated boxes, newspapers, food contact papers, etc. The estimated daily intake of BPA and its alternatives through the handling of thermal paper was 0.025 μg/kg bw/day for the general population. This is the first report on the occurrence of various new BPA alternatives in paper products from China, which will be helpful for further risk assessment and making responsible replacement decisions.

Flexible sensing devices have drawn tremendous attention in the past decades due to their potential applications in future hand-held, potable consumer, and wearable electronics. Here, we firstly developed an ultrasensitive wireless potentiometric aptasensor based on flexible freestanding graphene paper for kanamycin detection. Flexible graphene paper made from a simple vacuum filtration method was used as a biocompatible platform for effective immobilization of aptamer. A nuclease-assisted amplification strategy was introduced into this potentiometric biosensing system in order to significantly improve the detection sensitivity through a classic catalytic recycling reaction of target induced by the nuclease (DNase I). As expected, an ultra-low detection limit of 30.0 fg/mL for kanamycin was achieved. Furthermore, the developed potentiometric enzymatic aptasensor exhibits high selectivity, favorable flexibility, excellent stability and reproducibility, which holds great promising for its routine sensing application.

The biological deinking method using microbial enzymes is quite promising and rather eco-friendly. In this paper, we discuss about the impact of enzymatic deinking of newspaper pulp using ligno-cellulosic (cellulase, xylanase and laccase) and lipolytic enzymes. The individual treatment of paper pulp with enzymes (cellulase/xylanase) could enhance the paper brightness to about 32.86% whereas combinational effect could enhance only about 28.67%. There was a release of chromophores from phenolic and hydrophobic compounds released during the deinking process. Physico-chemical parameters of effluents were also found to be within the standard limits and the metals like iron, lead and zinc were not detected in the enzyme assisted deinking effluent sample. The heavy metals in the paper pulp was found to be reduced after enzyme treatment. The obtained effluent was found have low phytotoxicity and was safe for agricultural applications. Hence, the present report was found to be a suitable enzymatic deinking process which was eco-friendly that results in non-toxic effluents. The method also provides an avenue in water resource recycling within industries.

Conjugated amino acid with nano-biodegradable polymer was applied as ecofriendly and edible coating. Polystyrene sulfate (PSS) was highly investigated with dynamic light scattering (DLS) to measure the particle size and over charge (zeta potential measurements) of nano-polymer system as well as the homogeny of particle distribution in presence and absence of Lysine mixture (AA). In addition, topographical structure of the coating was studied for PSS, AA and conjugated one as well as Fourier transform infrared (FTIR) and Differential Scanning Calorimetry (DSC). Antimicrobial test cleared that the prepared conjugate described as broad-spectrum antibacterial agent as well as antifungal with different concentrations. The hydrophilic active ingredient is absorbed into fiber, distributed homogenously and kept out the fiber loaded with antimicrobial properties over all areas. Tensile strength of the paper sheets coated with uni-layer 200 µ thickness presented good improving in physical and mechanical properties of coated paper sheets as well as gives more fiber condensation according to Scanning Electron Microscope (SEM) topography.

Paper-based devices are always more gaining a relevant position in the field of sensors. The continuous demand for affordable, simple, sustainable, and portable devices, is making paper as the ideal basis towards the realization of analytical tools for the easy self-testing. In this work, we demonstrate, for the first time, the development of a disposable paper-based printed electroanalytical strip for reliable, rapid, and high-throughput detection of glutathione in blood. The detection is based on the thiol-disulfide exchange reaction, which produces a detectable compound easily oxidizable at a Prussian Blue/carbon black nanocomposite involving a favorable low-interference overpotential. This nanocomposite is mixed within a carbon-based conductive ink and successively screen-printed onto a wax-patterned filter paper. The employment of paper provides a reagent-free device, as a consequence of the reagents pre-loading within the testing area. After the experimental conditions have been optimized, glutathione has been detected up to 10 mM, with a detection limit of 60 μM, and a sensitivity of (0.102 ± 0.005) μA/mM. This sensor showed satisfactory repeatability (relative standard deviation equal to 10%, for detection of glutathione 1 mM), especially by considering the hand-made manufacturing process. The “real-world” applicability of this strip has been evaluated by quantifying blood glutathione at physiological levels and by recovery studies achieving satisfactory values.

One of the most important problems in dark fermentative hydrogen production is the need for the regulation of the ambient pH due to the formation of volatile fatty acids. For this purpose, alkaline chemicals are usually used; however, alkaline addition to the media increases salt formation, which negatively affects microbial activity. In this study, pH adjustment was performed by providing direct current as an alternative to alkali addition. Experiments were carried out batchwise and electricity was only applied to neutralize the acidic pH value. The waste paper hydrolysate was used as a substrate and the effects of applied voltage (0.25-3 V), substrate concentration (4.8-41.2 g/L at 1 V) and electrode distance (0.3-1.3 cm at 1 V) on hydrogen production performance was investigated. Voltages less than 1 V required too much time to keep the pH convenient and voltages more than 1.5 V adversely affected hydrogen production performance. Providing direct current to the fermentation media significantly reduced the adaptation phase. Conditions for optimal pH adjustment and hydrogen production were obtained at 1 V, 20 g glucose/L and 0.5 cm electrode distance. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Recycling of industrial wastewater meeting quality standards for agricultural and industrial demands is a viable option. In this study, paper and pulp industrial wastewater were treated with three biological treatments viz. aerobic, anaerobic and sequential (i.e. 20 days of anaerobic followed by 20 days of aerobic cycle), associated with simulation modeling by Mamdani Fuzzy Logic (MFL) model of some selected parameters. Electric air diffuser and minimal salt medium in sealed plastic bottles at control temperature were used for aerobic and anaerobic treatments, respectively. The significant reduction in chemical (COD: 81%) and biological oxygen demand (BOD: 71%), total suspended (TSS: 65%), dissolved solids (TDS: 60%) and turbidity (68%) was recorded during sequential treatment. The treated water was irrigated to determine its phytotoxic effects on seed germination, vigor and seedling growth of mustard (Brassica campestris). Sequential treatment greatly reduced phytotoxicity of wastewater and showed the highest germination percentage (90%) compared to aerobic (60%), anaerobic (70%) treatments and untreated wastewater (30%). Regression analysis also endorsed these findings (R2 = 0.76–0.95 between seed germination, seedling growth and vigor). MFL technique was adopted to simulate sequential treatment process. The results support higher performance of MFL model to predict TDS, TSS, COD, and BOD based on the physico-chemical water quality parameters of raw wastewater, time of treatment and treatment type variation. Based on these findings, we conclude that the sequential treatment could be a more effective strategy for treatment of pulp and paper industrial wastewater with efficiency to be used for agricultural industry without toxic effects.

The pulp paper industries release wastewater containing very complex organic and inorganic pollutants. These pollutants are discharged mainly pulping and bleaching process during paper manufacturing. The main gaseous pollutants hydrogen sulfides, sodium sulfide, methyl mercaptan, sulfur, and chlorine dioxide is reported for chronic, respiratory disorder and irritation to skin, eyes and cardiac problem along with nausea and headache. The major inorganic pollutants include ferrous, copper, zinc, nickel, and magnesium, which is reported for neurotoxicity, toxic to juvenile channel catfish (Ictalurus punctatus) and Accumulation to gill > liver > ovary > muscle. The detected major organic and inorganic pollutants are hexadecanoic acids, octacosane, β-sitosterol trimethylsilyl ether, 1-tetradecane, 2-methoxy phenol, trichlorocatechol, tetrachlorocatechol, chlorophenols, chloroguaiacols, chlorosyringols, chlorocatechols, terpenes, methanol, phenol, alkylated phenols, decalone, benzoic acid, abietic acid, and dehydroabietic acid. Several of these compounds are reported as endocrine-disrupting chemicals (EDCs). Therefore, direct toxicity of effluent to the reproductive system in aquatic flora and fauna are reported. Several reports have highlighted reduced gonad size, change in secondary sexual character, delayed maturity and suppression of sex hormone in fish rainbow trout (Oncorhynchus mykiss) and mosquitofish (Gambusia holbrooki) further the in-vitro studies of organic compounds on fish, Salmonella typhimurium, Vibrio fischeri, and Saccharomyces have shown inhibition in growth and luminescence properties. The presence of organic and inorganic pollutants in pulp paper industry wastewater causes phytotoxicity chromosomal aberration in Allium cepa. Thus the manuscript has concluded that detected pollutants produced foul odors and cause hermaphroditism in fish, hepatotoxicity and mutagenic effect. In addition, the growth of coliform bacteria in River and other aquatic resources has been reported due to contamination of PPI effluent. The studies also highlighted the presence of tannins, chlorophenols, dioxins, furans, biocide, fatty acids, and resin acids along with chlorolignine compounds as persistent organic pollutants (POP), which needs special attention for pollution prevention of rivers, lakes and other aquatic resources.

Development of recoverable and sustainable catalysts for environmental remediation still remains a great challenge. Here, we report a simple approach to immobilizing polyethylenimine (PEI)-templated silver nanoparticles (Ag PTNPs) onto the surface of cellulose filter paper for catalytic applications. First, branched PEI was utilized as a template to complex Ag(I) ions, then, sodium borohydride was applied as a reducing agent to generate Ag PTNPs. Thereafter, the formed Ag PTNPs were assembled onto filter paper via electrostatic interaction. The developed Ag PTNP-immobilized filter paper was characterized through different methods. We show that Ag PTNPs with a mean diameter of 4.6 ± 1.3 nm are able to be immobilized onto the surface of filter paper, and the Ag paper displays a remarkable catalytic activity and reusability towards the catalytic transformation of 4-nitrophenol to 4-aminophenol. The developed approach may be extended for the production of different kinds of NP-immobilized filter paper for the applications in sensing, environmental remediation, and biomedicine.

Thermophilic methane fermentation was a valid approach for handling the stillage eluted from ethanol fermentation of waste paper and kitchen waste. The wide organic loading rate (OLR) range (2-14 g VTS/(L d)) for stable performance and relatively high energy recovery efficiency (79.0%) were achieved, and OLR of 8 g VTS/(L d) was optimum for achievement of highest biogas evolution and VTS removal efficiency. Microbial community analysis revealed that hydrolysis of cellulose was the critical step for methane production from the stillage.

In this paper, a simple and effective ratiometric fluorescent nanoprobe for visual detection of hypochlorous acid (HOCl) has been developed by loading silicon coated rhodamine B (RBDS) nanospheres on the surface of amino-modified graphene oxide (GO-NH2) nanosheets. The fabricated nanoprobe exhibits dual-emissions peaked at 427 and 585 nm, under a single excitation wavelength of 365 nm. The blue fluorescence of GO-NH2 can be selectively quenched by oxidation of HOCl, while the red fluorescence of RBDS remain unchanged, resulting in a distinguishable fluorescent color change from blue to pink under a UV lamp. Nanoprobes present high selective and sensitive for HOCl determination with a limit of detection (LOD) of 2.92 μM. Moreover, potable paper sensor has been prepared by coating the ratiometric fluorescent probe on filter paper, which provides a convenient and simple approach for HOCl visual detection.

This paper describes a simple, low-cost, and highly flexible rapid prototyping method to construct electrochemical paper-based analytical device (ePAD) for multiplexed analyte determinations. The ePAD was composed of two electrochemical cell (EC) compartments, separated by hydrophobic barriers of wax, and screen-printed electrodes (SPEs) deposited directly over the surface of the filter paper. The ePAD was entirely constructed using an inexpensive craft cutter printer with no needed of a wax printer. The rapid prototyping method involves two steps: the deposition of the SPEs and the creation of the wax barriers. In this case, the SPEs were screen-printed on filter paper by using adhesive tape as mask by cutting the electrodes pattern with the cutter printer. Following, the wax barriers were created using stamps made of filter paper also cut with the printer and impregnated with wax. In the ePAD, each ECs containing an array of 4-working electrodes, allowing up to 4 replicates in a single measurement. Both ECs shared one counter and one reference electrodes, permitting the simultaneous multianalysis. The ePAD was successfully applied to simultaneous detection of paracetamol (PAR), caffeine (CAF), and ascorbic acid (AA) in drugs. PAR and CAF were detected in a sample using one EC and AA was detected, in a different sample, on the other EC, both with no chemical modifications in the working electrodes. Limits of detection of 0.04 mmol L−1 for PAR, 0.22 mmol L−1 for CAF, and 0.40 mmol L−1 for AA were obtained. The construction process proposed provide an easy way to implement screen-printing electrodes and wax barriers in filter paper to create electrochemical devices for fast and simultaneous multianalysis.

The present study was conducted to form polysaccharide-based multilayers of cationic starch (CS)/anionic starch (AS), and CS/carboxymethyl cellulose (CMC) on broke chemi-mechanical pulp (BCMP) fibers. It aimed to examine the buildup of CS/AS and CS/CMC polyelectrolyte multilayers (PEM) on the fibers surface, and explore the effects of PEM formation on the properties of the resulting papers. The assembly of PEM was analyzed by using zeta (ζ-) potential, water retention value (WRV), SEM micrographs, and paper properties such as thickness and strength. The results of ζ-potential inversions indicated successful constitution of PEM on the BCMP fiber surface by assembling CS/AS or CS/CMC multilayers. Further, larger ζ-potential variations occurred in depositing CS/CMC PEM, due to more charge of CMC, which presumably formed a layer with greater potential of absorption. Based on the SEM images, the surface of PEM-treated fibers was rougher, compared to the untreated fibers due to the coating with starch. Furthermore, the PEM fabrication resulted in creating fibers with higher degree of WRV, which was consistent with the significant improvement of the sheet strengths. Finally, the strength enhanced papers made from PEM-treated fibers with tensile index of about 37.33 ± 1.47 N m/g vs 22.24 ± 1.23 N m/g or 11.60 ± 0.57 N m/g for the papers made from original CMP and untreated BCMP fibers, respectively, may diminish the challenges related to web breaks in the paper machine conveying BCMP broke fibers.

The synthesis and employment of volatile toxic compounds as chemical weapons with a large-scale destructive power has introduced a new insidious threat over the last century. In this framework, the development of wearable sensing tools represents a critical point within the security field, in order to provide early alarm systems. Herein, a novel wearable electrochemical biosensor was developed for the rapid and on-site detection of mustard agents. Since a chemical attack is typically carried out by spraying these volatile agents into air, the sensor was designed in order to be able to measure mustard agents directly in the aerosol phase, further than in the liquid phase. The electrodes were screen-printed onto a filter paper support, which allowed to harness the porosity of paper to pre-load all the needed reagents into the cellulose network, and hence to realise an origami-like and reagent-free device. Mustard agent detection was carried out by monitoring their inhibitory effects toward the choline oxidase enzyme, through the amperometric measurement of the enzymatic by-product hydrogen peroxide. A carbon black/Prussian blue nanocomposite was used as a bulk-modifier of the conductive graphite ink constituting the working electrode, allowing for the electrocatalysis of the hydrogen peroxide reduction. After having verified the detecting capability toward a mustard agent simulant, the applicability of the resulting origami-like biosensor was demonstrated for the rapid and real-time detection of real sulfur mustard, obtaining limits of detection equal to 1 mM and 0.019 g·min/m3 for liquid and aerosol phase, respectively.

Graphene paper is a promising electrode material for use in flexible supercapacitors due to its good electronic conductivity and excellent mechanical characteristics. However, layers of graphene paper have a strong tendency to restack, resulting in a seriously reduced specific surface area and limited electrochemical performance. In this paper, restacked layers of graphene paper are reopened by a vacuum-assisted method, and carbon nanotubes (CNTs) are directly deposited on the enlarged space between the opened graphene layers. Consequently, an ordered carbon composite structure with alternately arranged graphene sheets and CNTs is constructed and exhibits increased specific surface area and a 3D conductive network. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and N2 adsorption/desorption measurements. The electrochemical performance was tested by galvanostatic charge-discharge test (GDC), electrochemical impedance spectroscopy (EIS) and cyclic voltammograms (CV). The obtained graphene/CNT paper exhibits a remarkably improved capacity of 170.8 F g−1, which is nearly two times higher than that obtained for a regular graphene paper.

In areas with high exposure to pathogen contaminated water and lack the economic means for water treatment, low cost and convenient point-of-use drinking water disinfection materials/devices are essential. Using a simple craft paper making method, Fe3+-saturated montmorillonite impregnated filter paper was constructed to filter live Escherichia coli (E. coli)-spiked water. The Scanning Electron Microscopic images of the E. coli cells in contact with the Fe3+-saturated montmorillonite impregnated filter paper showed: 1) Fe3+-saturated montmorillonite particles were uniformly coated on the cellulose paper fiber, creating large mineral surface for cell contact; and 2) E. coli cell membrane was dehydrated and damaged, resulting cell deactivation upon contacting with the Fe3+-saturated montmorillonite particles impregnated in the paper. The E. coli cells passing through the Fe3+-saturated montmorillonite impregnated filter paper were not viable as further confirmed by the microfluidic dielectrophoresis analysis. They remained non-viable at room temperature even after 5 days, as shown by the results from both the Colony Counting test and the Colilert test. More than 99.5% deactivation efficiency was achieved when the ratio of the volume of the E. coli contaminated water to the mass of Fe3+-saturated montmorillonite was maintained at

The interest in and use of microfluidic paper-based analytical devices (μPADs) has grown exponentially over the last decade. Cellulose, and modified cellulose, has been used for centuries for making chemical measurements but devices made with this material traditionally suffered from either poor detection limits and/or limited ability to provide quantitative measurements. μPADs address these problems by patterning paper to create microfluidic channel networks that can direct flow to different regions of the device without the need for external pumps used in most traditional microfluidic devices. Furthermore, because the devices are made from cellulose or modified cellulose using inexpensive manufacturing methods, the devices can be inexpensive and disposable. The ability to carry out multiplexed analysis without external pumps using inexpensive, disposable devices makes μPADs ideal for point-of-care (POC) analysis. The interest in μPADs has led to a number of excellent comprehensive reviews in the field; in this review, we do not attempt to reference the entire field but instead seek to highlight major developments as well as areas that will be important for future development of this field.

Environmental pollution due to various elements is increasing all across the planet owing to their use in industrial processes. The tobacco plants and the vegetables used in the manufacturing of smoking paper may accumulate these elements from the environment. Thus, tobacco and smoking paper may be relevant contributors among the content of elements in cigarettes, including some emerging pollutants such as rare earth elements (REEs). Thirty-two elements related to hi-tech industrial processes were analyzed in tobacco, rolling paper, and filters (n = 257 samples) by ICP-MS. A variety of industrial brands and “roll-your-own” cigarette papers were considered. The potential maximum daily exposure to these elements by a hypothetical heavy smoker was calculated for each type of cigarette. We found significant differences in the levels of most elements, both in the tobacco and in the paper. Black tobacco cigarettes contained the maximum levels. We found that the paper used in roll-your-own cigarettes may significantly modify their concentration of elements. Fast-burning, bleached, and flavored papers also contribute to higher levels of these pollutants. Thus, the differences in theoretical exposure depending on the type of cigarette consumed–either branded or hand-rolled–may be very striking, of up to 35–40 times. In addition to the number of cigarettes consumed per day, it is necessary to consider the type of cigarette consumed to assess the risk of exposure to toxic elements. Tobacco paper is a prominent source of exposure to toxic elements. Cigarette smoke is another source of exposure to emerging contaminants such as REE.

Life Cycle Assessment (LCA) has been used to evaluate the life-cycle Greenhouse Gas (GHG) emissions of pulp and paper production, and most previous studies rely on process-based models for specific product types (e.g., printing paper), industry-average data, or information from a few mills. In this work, a data-driven approach is used to quantify GHG emissions intensities of different paper products manufactured by the U.S. mills. Facility-level emission data collected from publically available governmental databases and mill-level production data collected from the private sector were integrated to track the GHG emissions for different product lines and paper products in mills (in total, 165 mills were matched and analyzed). The results highlight the ranges of GHG emissions intensities by different product groups and categories, and can be used as a transparent data source for LCA practitioners, policymakers, and the pulp and paper industry to perform further analysis on carbon accounting and strategic planning for GHG mitigation.

Epoxide-bearing filter paper was first prepared by surface-initiated reversible addition-fragmentation chain transfer (RAFT) copolymerization of glycidyl methacrylate (GMA) and poly(ethylene glycol)methacrylate (PEGMA). Without the need for activation step, the capture peptide nucleic acid (PNA) probes carrying a C-terminal lysine modification can be directly immobilized on the surface-grafted poly[glycidyl methacrylate-ran-poly(ethylene glycol)methacrylate] (P(GMA-ran-PEGMA)) through ring-opening of epoxide groups in the GMA repeating units by amino groups in the PNA’s structure. The success of P(GMA-ran-PEGMA) grafting on the filter paper and subsequent PNA immobilization was confirmed by fluorescence microscopy, Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy. Colorimetric detection with signal amplification upon DNA hybridization relies on sandwich-hybridization assay employing another biotinylated PNA strand as a reporter probe together with streptavidin-horseradish peroxidase conjugate (SA-HRP) and o-phenylenediamine (OPD) substrate. It was found that increasing ionic strength during the DNA hybridization step by addition of NaCl can increase the signal intensity, which can be visualized by naked eye. The sensing platform showed the best performance in preventing non-specific adsorption from the non-complementary DNA and discriminating between complementary and single-mismatched targets of at least 50 fmol without the requirement for stringent hybridization or washing condition. This superior ability to suppress non-specific adsorption of non-target DNA as well as other non-DNA components may be explained as a result of hydrophilic PEGMA repeating units in the surface-grafted copolymer.

In this work, we constructed a sensing system on Janus paper with hydrophilic side and hydrophobic side via depositing polymer precursor onto one side of qualitative filter paper. Water in humid environment (including liquid water, condensed moisture airflow and gaseous humid atmosphere) will be captured and gathered in the hydrophilic region of Janus paper due to the asymmetric hydrophobicity and hygroscopicity, which can induce the novel directional deformation. Additionally, MWCNTs (multiwalled carbon nanotubes) were loaded onto hydrophobic region beforehand to construct conductive network. The resistance of the conductive network changes synergistically as the Janus paper deforms in humid environment. Thus, the novel Janus paper realized the induction of environment humid factors, and conversion from the deformation signals to the desirable electric signals. The Janus paper also shows excellent stability in cycle use.

Many paper products are coated with plastic to improve their quality and stability. However, this limits recycling and recovery options and the plastic-coated waste paper is mostly disposed in landfills. Such practices are uneconomical and contrary to sustainable waste management. In this work enzymes of the white rot fungus Dichomitus squalens were investigated for possible delamination of plastic-coated waste paper. Enzymes were found capable to release the polyethylene foil from plastic-coated paper which resulted in 88.6-91.5% mass loss. The delamination rate, however, was depended on the ratio between plastic-coated paper and volume of enzyme filtrate. Results of a consequent experiment showed that enzymes are also efficient when plastic-coated paper is treated in a sequencing batch reactor resulting in 88.2-90.6% mass loss. The system was fully functional up to the 5th cycle; afterwards, the delamination rate reduced due to high thickness of the waste paper sludge. The enzyme activity, however, was still very high; with the laccase activity at the end of the experiment above 900 U/L and manganese peroxidase above 250 U/L. Our results demonstrated, that plastic-coated waste paper has the potential to be efficiently recovered instead of being disposed in landfills.

Building bricks were produced by utilizing deinking paper mill sludge (DPMS) and alluvial soil by varying percentage of sludge at different firing temperatures. Different mix proportions were prepared with 0%, 5%, 10%, 15%, 20%, 25% and 30% of DPMS incorporation in alluvial soil by weight. Three firing temperatures of 900 °C, 950 °C and 1000 °C were investigated to simulate the typical condition of kiln. The density, firing shrinkage, water absorption, efflorescence, apparent porosity, compressive strength and thermal conductivity of the bricks were determined. The XRD and microstructural analysis of brick specimens were also studied. The optimum firing temperature was 950 °C. The thermal conductivity decreases with increase in percentage of deinking paper mill sludge. It was found that 15% deinking paper mill sludge gives optimum strength at firing temperature of 950 °C. Developed bricks satisfy the requirements of class 10 of Bureau of Indian Standards (BIS), in terms of efflorescence, compressive strength and water absorption. Thermal conductivity results show that the developed brick was thermally more insulated than the conventional bricks and can be used as alternative to conventional bricks. This will address the issue of waste management through cleaner production and show the ways towards sustainable, economical and energy efficient construction.

Graphical abstract, Highlights • Detection of cytokine storm biomarkers with mobile biosensors. • Immunosensors are made solely of cellulose modified with antibody-decorated nanoparticles. • Turnaround time under 10 min. • Detection of biomarkers in respiratory samples allows monitoring local inflammation. • Compatible with decentralized health care schemes., Decentralizing COVID-19 care reduces contagions and affords a better use of hospital resources. We introduce biosensors aimed at detecting severe cases of COVID-19 in decentralized healthcare settings. They consist of a paper immunosensor interfaced with a smartphone. The immunosensors have been designed to generate intense colorimetric signals when the sample contains ultralow concentrations of IL-6, which has been proposed as a prognosis biomarker of COVID-19. This is achieved by combining a paper-based signal amplification mechanism with polymer-filled reservoirs for dispensing antibody-decorated nanoparticles and a bespoken app for color quantification. With this design we achieved a low limit of detection (LOD) of 10−3 pg mL-1 and semi-quantitative measurements in a wide dynamic range between 10−3 and 102 pg mL-1 in PBS. The assay time is under 10 min. The low LOD allowed us to dilute blood samples and detect IL-6 with an LOD of 1.3 pg mL-1 and a dynamic range up to 102 pg mL-1. Following this protocol, we were able to stratify COVID-19 patients according to different blood levels of IL-6. We also report on the detection of IL-6 in respiratory samples (bronchial aspirate, BAS) from COVID-19 patients. The test could be easily adapted to detect other cytokines such as TNF-α and IL-8 by changing the antibodies decorating the nanoparticles accordingly. The ability of detecting cytokines in blood and respiratory samples paves the way for monitoring local inflammation in the lungs as well as systemic inflammation levels in the body.

Adding biochar to paper mill biosolids (PB) amendments may affect PB mineralization rate and nitrogen (N) availability. The objective of this 224-day incubation study was to evaluate the effect of amending two PB types varying in carbon (C)/N ratio (PB1, C/N = 24; and PB2, C/N = 13) with three rates (0%, 2%, and 5%) of pine (Pinus strobus L.) biochar produced at 700 °C on the dynamics of total C, total N, mineral N, N mineralization rate, and microbial biomass C (MBC) and N (MBN) in two agricultural soils (Kamouraska clay and St-Antoine sandy-loam). Two reference treatments were also included, namely, mineral fertilization and unamended soil. Total soil C concentration remained stable over the incubation period, whereas a decrease in total soil N was observed in both soils. In comparison with the unamended soil, the application of PB significantly increased total N, NH4-N, NO3-N, net mineralized N, applied N mineralization rate, and MBC in both soils. In comparison with the application of PB alone, biochar addition increased total C and MBC but decreased NH4-N, NO3-N, net N mineralization, and applied N mineralization rate in both soils. The co-application of biochar and PB1 resulted in the sequestration of mineral N released, which was more pronounced in the Kamouraska clay soil. The co-application of biochar and PB2 resulted in moderate release of mineral N. This study showed that the co-application of biochar and PB can benefit agricultural soils by improving NO3-N retention in agroecosystems while increasing organic matter and promoting microbial biomass.

Contaminated water contains various types of pollutants, the removal of which requires two or more technologies. It is imperative but challenging to develop water purifier for simultaneous removal of multiple pollutants for the sake of easy operation, low cost, and etc. Previously reported multifunctional purifiers are normally nanoparticles which require caution during use. Here, we describe a design of paper-like multifunctional purifier, which has biomass-based structure by grafting polyethylenimine derived quaternary ammonium compounds onto three-dimensional bacterial cellulose substrate. Compared to similar materials reported previously, our product exhibited strikingly higher adsorption capacities towards various metal ions including Pb2+, Cu2+, and Cr6+, anionic organic dyes including congo red, methyl orange and methyl red, and excellent disinfection efficiency towards both Gram-negative and Gram-positive bacteria. Remarkably, this purifier also demonstrated effective removal of the three contaminative species simultaneously from both simulated and local polluted water. With more virtues of superior reusability and extreme handy convenience, we hope our molecular design could inspire further efforts on the rational construction of multifunctional water purifier with easy operation. We reckon our material to have strong potential for the possible use in water treatment, especially in regions that are short of environmental infrastructures.

A paper-based electrochemical immunosensor was developed for the detection of cancer antigen 125 (CA125) by screen-printing technique. The reduced graphene oxide/thionine/gold nanoparticles (rGO/Thi/AuNPs) nanocomposites were compounded and coated onto the working electrode of immunosensor for CA125 antibody (anti-CA125) immobilization and detection signal amplification. The detection principle was based on the fact that the immunocomplex formed by specify binding of CA125 antibody and antigen could reduce the current response of thionine, which was proportional to the corresponding concentration of CA125 antigen. The immunoassay results showed that the linear range of CA125 was from 0.1 U mL-1 to 200 U mL-1 with the limit of detection (LOD) of 0.01 U mL-1 at signal to noise of 3. Quality control serum samples measured by our proposed immunosensor showed acceptable agreement with traditional ELISA method with the relative error less than 8.05%. The immunosensor exhibited good electrochemical performance with high reproducibility, reliability, stability and accuracy. The proposed immunosensor could be used for the determination of CA125 and had the potential for point-of-care testing (POCT) of other tumor marker.

Toilet paper (TP) fiber is a major slowly biodegradable constituent of municipal wastewater. Oftentimes, they cannot be efficiently removed during the preliminary treatment of wastewater treatment plants (WWTPs), especially for those without installation of primary clarifiers. Although fine-mesh sieves are effective in removing fibers, their applications are not common in current WWTPs. Therefore, it is critical to understand the degradation of TP fibers during the secondary wastewater treatment. In this study, the effects of solids retention time (SRT) and microbial community on the hydrolysis kinetics of TP were investigated in sequencing-batch activated sludge systems. Meanwhile, the influence of the addition of readily biodegradable organics such as glucose on fiber degradation was also studied. It was found that the overall degradation of TP linearly increased versus SRT. At 40-day SRT, approximately 83% of TP was degraded. The hydrolysis coefficient at 40-day SRT (0.116–0.137 d−1) significantly increased compared to those at SRTs smaller than 20 days (0.025–0.034 d−1), which was probably due to the stepwise hydrolysis of cellulose and hemicellulose fibers, as well as the synergistic enzymatic activities owing to the enhanced microbial diversity at larger SRTs. Actively functioning fiber-degrading Cellvibrio genus was identified as the dominant driver of fiber hydrolysis. Interestingly, it was discovered that fiber-degrading microbial communities were inefficient at consuming either glucose or acetate. Therefore, the addition of these substrates did not enhance TP degradation.

In this work, the effect of liquid evaporation on electrochemical measurements with electrochemical paper-based devices (ePADs) is studied. The time evolution of cyclic voltammograms of ferricyanide is used to study the effect of liquid evaporation under different conditions of relative humidity and air currents. Moreover, the enclosure of ePAD channels with adhesive tape is evaluated in terms of minimising the evaporation, as well as increasing the sensitivity in the electrochemical determination of horseradish peroxidase in long-term assays. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 760876.