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The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking.

In order to obtain a lignin-based adsorbent with low cost, simple operation and no further modification, a calcium lignin adsorbent was prepared from chemical mechanical pulping (CMP) waste liquor by directly calcification from lime. The calcium lignin was characterized by BET, SEM, TEM, FT-IR and solid-state NMR analyses. The results showed that the molecular structure of the calcium lignin particles did not change when compared to sodium lignin, the formation mechanism of calcium lignin was revealed. The initial COD and lignin contents of CMP waste liquid were 54858 mg/L and 24.39 g/L, the conversion rate of lignin can reach 71.36% when was deal with lime. Thus, most of the lignin resources in the waste liquid were recovered. The middle-stage wastewater (MSWW) of pulping and papermaking was dealt with calcium lignin, the COD removal rate was up to 85.83%. The adsorption isotherms and kinetics were well fitted by the Langmuir model and pseudo-second-order kinetic model, respectively. Lime was regenerated from the used calcium lignin with high-temperature calcination, the conversion rate of calcium ions can reach 83.56%. Overall, the calcium lignin prepared by the one-step method exhibited great potential for effectively removing COD from middle-stage wastewater.

Excellent mechanical and electrical properties of graphene-based paper-like materials are essential for applications in flexible conductors, energy-storage devices, etc. The graphene oxide (GO) supernatant separated by centrifugation and ultrasonication has been used to prepare graphene oxide paper and reduced graphene oxide paper (rGOP) with high strength and conductivity. However, this method has cumbersome steps and low supernatant concentration, which greatly increases time and energy consumption, and is not suitable for rapid batch preparation of high-strength and high-thickness rGOP. Herein, a high-speed mechanical shearing method has been used to efficiently exfoliate graphite oxide suspension into high-concentration GO slurry with large lateral size, and rGOP has been further prepared by blade coating and HI acid chemical reduction. Compared with the product prepared by ultrasonic exfoliation method, the average area of GO sheets obtained via the mechanical shear exfoliation method can reach around 16.31 μm2. As a result, the mechanical properties and conductivity of the prepared rGOP have been increased by 30% and 23.5%, respectively, with the tensile strength and electrical conductivity of 478.2 MPa and 208.4 S/cm being obtained. The developed method is of great significance for the large-scale production and emerging applications of lightweight and high-performance rGOP.

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.

The efficiency of xylano-pectinolytic enzymes, co-produced by a single microbial strain Bacillus pumilus, was analysed for the recycling of mixed office waste paper through deinking and compared with the alkaline chemical deinking method. Enzymes showed maximum deinking at pH 8.5, pulp consistency of 10%, xylanase-pectinase dose of 12 and 4 IU per gram pulp, respectively, after 120 min of deinking period, and temperature at 50 °C. A chemi-enzymatic approach was employed with xylano-pectinolytic enzymes and various concentrations of deinking chemicals, which showed that enzyme-treated mixed office waste pulp requires only 40% chemicals for deinking, in order to get the almost same level of various handsheets properties, as obtained by the chemical method with 100% chemicals. Similarly, the effluent load of BOD and COD contents was also decreased by 17.90 and 19.75%. This combinational approach of deinking significantly improved the various properties of the handsheets and resulted in gain of 7.5, 9.38, 6.33 and 11.65% in tear factor, burst factor, breaking length and viscosity of the handsheets, while the effective residual ink concentration analysis of deinked handsheets of mixed office waste paper showed deinking efficiency of 22.45%, which revealed the removal of ink particles during enzymatic deinking steps.

The study is a first investigation of the feasibility to preserve recycled fillers (e.g. calcium carbonate, kaolin) from deinking paper sludge for newspaper production using an alternative approach respect to the actual methods. Deinking paper sludge was incinerated at 575 °C. The thermal stability of the incinerated sludge (ash) was evaluated by infrared analysis. Subsequently, the resulting ash was bleached by sodium dithionite. The particle size of the ashes was analysed by laser diffraction. The effect of recycled fillers on recycled paper pulp, after blending, was evaluated by the analysis of the physical and optical properties of the obtained paper sheets. Analysis showed the conservation of the calcium carbonate and other fillers’ molecular structure, both after incineration of the sludge and after bleaching. The dithionite treatment of the ashes resulted in ISO brightness levels of more than 70. The brightness was stable over one month. Paper sheets made by blending the bleached ashes with recycled paper showed an improvement of brightness and opacity but a decrease in terms of porosity and breaking length compared to paper sheets made without any filler. The proposed method still requires further studies to evaluate the economical application but offers an opportunity for the recycling of inorganic materials and valorisation of the sludge.

Detecting the concentration of free chlorine is important for monitoring the quality of water. In this study, we report a nanohybrid paper-based chemiresistive sensor that can be used with smartphones to detect free chlorine ions. The sensor was fabricated using a simple and standardized coating process. The graphene and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanohybrid paper-based sensing device exhibited a more stable and intuitive response to free chlorine than that exhibited by the device using only PEDOT:PSS. The nanohybrid paper-based sensor was sensitive to free chlorine concentrations in a linear range of 0.1-500 ppm, and the limit of detection was 0.18 ppm. The sensor showed specificity for free chloride ions and detection capability in samples. The sensor was integrated as a module with an electric readout system, and the measured signals and results could be displayed in real time on a smartphone. Therefore, the proposed sensing platform is suitable owing to its portability, low cost, ease of use, and capability for on-site water quality measurement.

In this study, different methods for incorporating mixed or laminar copper microparticles (CuMPs) during papermaking were evaluated to determine the optimum paper-making process and correlate particle concentration and shape with antimicrobial activity. The addition of CuMPs during the disintegration of dry pulp stage was observed to produce a paper with uniformly distributed CuMPs, as determined through optical microscopy and UV–Vis spectroscopy analyses by measuring absorbance spectra in different areas of papers. Determination of two indices related to the concentration and distribution of copper will allow to predict the copper content in other papers. CuMP-paper samples were evaluated for structural, optical, and mechanical strength properties according to paper industry standards. Quantitative analyses by atomic absorption showed that between 24 and 39% of CuMPs were embedded in the paper fibre, independent of particle type. Finally, antibacterial activity analyses were performed according to ISO 20645 and ISO 20743. The results showed that papers with 0.30 g of incorporated CuMPs have antimicrobial activity, independent of particle morphology, with effects observed towards Gram (+) and Gram (−) bacteria and fungus. Furthermore, the evaluation of antimicrobial activity at different times of exposure to the microorganisms showed differences in effects that were dependent on the shape of the CuMPs incorporated into paper, where laminar particles exerted a sufficient effect, while no or a slight effect was observed for mixed CuMPs against Aspergillus niger.

Paper has become the basic elixir in everyone's activities and usage of paper has increased day by day, the waste generated by paper is also enormous. The primary source of paper is wood (tree) yet, waste paper is environmentally good and biodegradable; however, it is the primary source of deforestation. Current research aims to find an alternate way to recycle paper in the biological approach. Hence in our work, twelve cellulose-producing bacteria were isolated, out of which one bacterial strain proved to be the best. Cellulase enzyme was extracted and purified, and used for enzymatic de-inking of photocopy papers. The optimal conditions for cellulase synthesis were at 60 °C, glucose as the only carbon source, and potassium nitrate as the nitrogen source. The enzyme demonstrated excellent de-inking at a lower pulp consistency of 3% with a 20% enzyme dose. The cellulose and hemicellulose levels decreased, which can be attributed to fiber breaking. Further, the changes in the functional groups identified by Fourier-transform infrared spectroscopy analysis and the changes in the surface morphology of the pulp fibers were obtained using scanning electron microscope analysis.

Objective: This study mainly focussed how foldscope can be used as an efficient viewable tool to detect in morphological and anatomical investigation of various bioactive medicinal plants. Microscope provides a beneficial instrument for visualization of living cells. Its cost is very high which is not affordable for rural based educational institutes. Foldscope is the ultra-affordable and versatile, paper microscope designed to be extremely portable, durable and to give optical quality similar to conventional research microscopes. Methods: For enhancing scientific temperament among rural children, Indian Born Scientist (Dr. Manu Prakash) has introduced an ultra-low-cost foldable origami-based approach for large-scale manufacturing of microscope, specifically demonstrating bright field, dark field and fluorescence microscopes. However, its potential as in research tool in the area of aromatic medicinal plants is still not known. The slides were prepared by own and were observed with the magnification power of 140X. Results: The result of the present study reported that the Foldcsope images revealed viable stained areas in the respective plant parts like trichomes, stomata, pollen grains, stem and leaf of different medicinal plants and indicating their live activities. Conclusion: Based on the attractive images captured from the Foldscope, the uses of foldscope were recommended to public. Previously we had organized some awareness cum demonstration programme regarding foldscope and its applications in the field of science education in the different educational institute of Erode District, Tamilnadu. Based on the clarity of images and easy handling of Foldscope the uses of origami microscope were recommended for higher studies.

The recycling of waste paper has been an effective way to achieve the environmental-friendly growth of papermaking industry. Focusing on the mixed-pulping process which has been generally employed, to ensure the required properties of the deinking pulp (DIP) and minimize the purchase cost of waste paper, an intelligent model scheduling the mixing ratio of waste paper was developed in the study. Primarily, driven by the field data of mixing ratio of waste paper and DIP properties, the prediction models of DIP properties were developed by SVM, GA-SVM, and BP-NN algorithms. Subsequently, based on the best prediction model, the scheduling model for the mixing ratio of waste paper was set up by NSGAII algorithm. The experimental results showed that, based on the obtained best BP-NN prediction model of DIP properties, the developed NSGAII scheduling model for the ratio of waste paper could achieve excellent scheduling results under the rigorous constraints and multi-objective. Compared with the previous study, the developed prediction and scheduling models in this study reduced the purchase cost of waste paper by 2.16%, and improved the acceptable proportion of DIP property from 56.07% to 100%.

Carbonization of biomasses is an effective and important approach to recycle biomass waste. The tissue papers are one of the most common household trash and waste lots of natural resources and energies. Herein, the one-step carbonization and activation treatment was applied on two kinds of tissue papers to transform them into porous carbons. It was found the precursor structure and composition as well as the calcination temperatures play key roles to control the pore structures. As the active materials of supercapacitor electrodes, the resultant porous carbons obtained from different paper precursors and calcination temperatures (700–900 °C) presented different electrochemical performances. The microporous carbons derived from the 700 °C calcination of the tissue paper using the wood pulp as the raw material showed high capacitance up to ~ 200 F/g, providing a simple but effective way to recycle biomasses.

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.

Herein, a fully paper‐based all‐solid‐state supercapacitor with functionalized cellulose paper as electrodes, carboxymethyl cellulose gel as solid electrolyte and cellulose paper as separator was fabricated. The electrode was fabricated by a conventional papermaking process with silver‐modified fibers and graphene oxide (GO)‐modified fibers followed by reduction of GO. The Ag‐modified fibers and GO‐modified fibers were obtained by in situ growth of Ag nanoparticles and self‐assembly of GO sheets on cellulose fibers, respectively. Ag‐modified fibers act as a flexible current collector with rich three‐dimensional interconnected electron transport pathways to make the reduced GO‐modified fibers as electrode materials to achieve high conductivity (1.93 Ω sq−1) and high‐rate capability. Simple drying can reduce 40% weight of the supercapacitor to facilitate transportation and storage, and its capacitance efficiency can be recovered by wetting when needed. This work opens up a new way of developing cheap, green and high performance full‐paper flexible electronics by conventional papermaking process.

Paper has many uses such as in writing, printing, packaging, paper money, cheques voucher, cleaning, as construction materials, etc. Based on its applications, paper may be characterized as bank paper, book paper, bond paper, construction paper, cotton paper, electronic paper, photo paper, wallpaper, etc. The popular raw materials used to make paper are esparto-grass, straw, wood, flax, hemp, jute and rags-cotton and linen. The paper manufacturing process consists of two main stages: pulp making and conversion of pulp into paper. The process of producing pulp may be done by chemical or mechanical means, or by a combination of both depending on the nature of raw material used and the end application of the produced paper. Three operations are required to manufacture paper that are beating, conversion of pulp to paper and finishing. This chapter comprehensively covers the types of papers, their uses, raw materials and their manufacturing processes. Pulp and paper mills have adverse effects on the environment such as depletion of forest covers, and chemical pollution caused by liquid effluent discharges, solid wastes and air emissions from particulates, H2S, NOx, SOx. These have been covered in detail including means to reduce their emissions and treatment methods.

Enzyme use has provided boost to the technoeconomics of many industrial processes. In this chapter, we summarize different cellulase-based industrial processes for preparation of paper, pulp, brewing products, and different foods. This review presents a brief chemistry and mechanism of cellulose degradation by the cellulase enzyme. Also, cellulase production abilities of many microbial species have been addressed in this chapter. Cellulase plays a major role in production of good-quality paper and pulp. It’s used to debark the biomass and to remove lignocellulosic part. This enzyme also has application in recycling of used paper by deinking and biobleaching. Cellulase enhances freeness and drainage ability of the fibers without compromising the brightness of the fibers. In brewing industry, cellulase in combination of other enzymes is used to extract the more sugar for better-quality alcohol production. Cellulases have a wide range of potential applications in food and beverage processing, production of fruit and vegetable juices, and improvement of methods for extraction, clarification, and stabilization.

The development of renewable energy sources minimizes the burning of fossil fuels for clean and green environment. Electrochemical energy storage/conversion device pays a way towards sustainable development that concludes an emerging field in the trends of the research community. Prominently, the functional materials with suitable structure and property determine the performance and durability of the devices. In recent times, graphene with its tremendous properties play a major role in electrochemical energy device applications. Meanwhile, the graphene-based electrodes were fabricated by various coating techniques on existing electrodes that utilized for energy device fabrication. Apart from these, it is also fabricated in a paper like a form (self-supported or free-standing) with its remarkable high conductivity, flexibility, robustness and electrochemical behavior which have been nominated for fabrication of flexible energy devices. Paper-like electrodes become an emerging field to fabricate a light-weight and flexible electronic devices for future prospects. Thus, we have summarized a synthetic strategy of graphene paper and its properties that potentially focused on flexible device fabrication in both the energy storage and conversion system. Hence, this review boosts up the forthcoming researchers to enhance the device performance with interrelating free-standing graphene and other host material.

In this early study, new cement-bonded bi-composite fibreboard (FB) was made from water hyacinth (WaHy) and waste paper (WP). Ordinary Portland cement (PdCe) used as a binder was mixed with other two additives: gypsum plasters (GyPl) and wood ash (WdAh), in defined proportions to form bonding matrices. The WP and WaHy were pre-treated and a linked process was developed for the mixing and consolidation steps. The FBs produced were based on different proportions of composites, binder, and additives mixed. The FBs produced were made from different proportions of composites, binders, and additives. Improved tensile strength was observed for bi-composite FB from WaHy mixed with WP. In general, FBs having densities in the range of 0.50–0.57 g cm−3 were compared favourably with the ASTM and ANSI standards (95%), thus making the FBs a potential alternative for building and construction purposes. More elaborate research with advanced analytical techniques is hereby suggested.

The direct coating of graphene sheets obtained by electrochemical exfoliation on commercial paper renders the preparation of highly conductive flexible paper substrate for subsequent deposition of polyaniline (PANi) nanorods via electrochemical polymerization. The deposition of PANi can be well-controlled by adjusting the electrochemical polymerization time, leading to the formation of PANi coated graphene paper (PANi-GP). The as-prepared electrode exhibited high areal capacitance of 176 mF cm−2 in three-electrode system at a current density of 0.2 mA cm−2, which is around 10 times larger than that of pristine graphene paper due to the pseudocapacitive behavior of PANi. In-situ Raman test was used to determine the molecular changes during redox process of PANi. More importantly, all-solid-state symmetric capacitor assembled with two PANi-GP electrodes in a polymer electrolyte delivered an areal capacitance of 123 mF cm−2, corresponding to an areal energy density of 17.1 µWh cm−2 and an areal power density of 0.25 mW cm−2. The symmetric capacitor held a capacitive retention of 74.8% after 500 bending tests from 0 to 120°, suggesting the good flexibility and mechanical stability. These results showed the great promising application in flexible energy-storage devices.

Mercury intrusion porosimetry (MIP) is an inexpensive and common technique to characterize porous structures like paper. One major limitation of MIP is the lack of information about the arrangement of pores in the structure, information that is particularly relevant for multilayer structures such as thickness-structured paper. In this article, results from Synchrotron X-ray 3D microtomography are combined with MIP data to provide in-depth and improved information about the structures.

The deinking of mixed office waste paper by cellulase, M/Las (modification of laccase aspartic acid system), and C-M/Las (cellulase synergistic modification of laccase aspartic acid system) was investigated. The fiber morphology parameters, hydrogen bond patterns, cellulose crystallinity, and fiber microstructure were observed via fiber quality analyzer (FQA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that the effective residual ink concentration of enzyme deinked pulp decreased compared with blank pulp (pulp without enzymatic treatment). The deinking efficiencies of C-M/Las, cellulase, and M/Las were 18.17%, 14.01%, and 12.31%, respectively. FQA analysis indicated that the fiber length and curl index decreased, while the fiber width slightly increased. FTIR analysis revealed that after cellulase, M/Las, and C-M/Las treatment, the content of intermolecular hydrogen bonds increased by 14.65%, 13.37%, and 19.80%, respectively. This indicates that there is a synergistic effect between cellulase and M/Las. XRD showed that the cellulose crystallinity decreased after enzymatic deinking. SEM micrographs of fibers treated with enzymes revealed that the fiber surface became rough and more fibrils appeared. The water retention value was increased after enzymatic deinking.

Here we report the construction of CoFe2O4 coating on carbon fiber and the coated paper was used as the interlayer between the separator and cathode of Li-S batteries. The amorphous CoFe2O4 coating was deposited by the industry-oriented spray pyrolysis technique and carbon fiber was completely enwrapped by the coating. Compared to the non-coated carbon fiber, the coated carbon fiber as the interlayer exhibits a superior reversible capacity of 1086 mA h g−1 at moderate current of 0.1C and a low decay rate in the capacity of 0.043% per cycle after 1000 cycles at 1C. Excellent long-term cycling life and rate capacity were also achieved through the coated interlayer. The specially designed interlayer showed remarkable capability to trap effectively the intermediate LPS (lithium polysulfide). The significantly inhibited “shuttle effect” of LPS would give insight into designing and making the interlayer by using new coating materials for enhanced performances of the Li-S batteries.

The COVID-19 pandemic has highlighted the need for diversity in the market and alternative materials for personal protective equipment (PPE). Paper has high coatability for tunable barrier performance, and an agile production process, making it a potential substitute for polyolefin-derived PPE materials. Bleached and newsprint papers were laminated with polyethylene (PE) coatings of different thicknesses, and characterised for their potential use as medical gowns for healthcare workers and COVID-19 patients. Thicker PE lamination improved coating homogeneity and water vapour resistance. 49 GSM bleached paper with 16 GSM PE coating showed high tensile and seam strength, and low water vapour transmission rate (WVTR). Phi-X174 bacteriophage testing revealed that paper laminated with 15 GSM coating hinders virus penetration. This research demonstrates that PE laminated paper is a promising material for low cost viral protective gowns., Graphical abstract Image 1

The industrial solid waste generation and its stockpile disposal have major environmental consequences. These consequences could be minimized through the solid waste application as a raw material in other industries. The current study focusses on the utilization of lime sludge with boiler ash synthesized nanosilica for production of belite based clinker at relatively lower temperature. Lime sludge was also used in combination with fly ash and boiler ash to check the synthesis of compounds at varying temperatures. Nanosilica was synthesized from pretreated boiler ash through alkali treatment and acid precipitation. The synthesized nanosilica has been characterized for specific surface area, crystallinity, surface functional groups and size. Three different mixtures, containing lime sludge with nanosilica, fly ash, and boiler ash are fired at temperatures ranging from 900 °C to 1200 °C and characterized for the synthesis of belite. Conventionally, belite is synthesized above 1200 °C, whereas the combined application of lime sludge and nanosilica reduces the temperature of belite synthesis to 900 °C without pre calcination or addition of any chemical stabilizer. In the case of lime sludge and boiler ash blend, belite formation takes place at the higher temperature (1100–1200 °C). Anorthite synthesis takes place in case of lime sludge and fly ash blend, due to high percentage of alumina present in fly ash. Lime sludge and nanosilica based belite clinker are used to develop newer cementitious binder. Hydration and strength properties of developed binder proved worthy as building materials. This study will present alternatives for sustainable utilization of lime sludge, fly ash and boiler ash in construction.

Increasing society awareness on sustainable development and environmental pollution has led to increase in utilization of industry-based secondary fibers such as old newsprint, mixed office waste, and old magazines for paper making. Paper recycling is necessary to reduce dependency on virgin wood pulp and to avoid disposal problem for waste paper. Deinking, the most important process in waste paper recycling, is traditionally handled by large quantities of chemicals, is expensive, and is damaging the environment. Microbial enzymes offer a better alternative for eco-friendly deinking of waste paper by reducing chemical consumption, which leads to cost-cutting, energy saving, and lower waste production. This chapter describes microbial enzymes reported for waste paper recycling and comparison of enzymatic deinking with other conventional methods.

Civil Construction Industry impacts significantly the environment, being one of the most critic factors related to elevated production of Civil Construction Residue (CCR). Among CCR produced, the Kraft paper package acquires notoriety, due their large use on material packaging, such as Portland cement and lime, then, present a high production rate and offer contamination potential, lack of collection logistics and nearly any reuse. In this scenario, the study and development of alternative constructive materials which applies the sustainability concept and CCR recycling have acquired great relevance in the sector. It is highlighted the residue incorporation on masonry soil-cement blocks, due its block are not submitted to the sintering process. Then, the present research intend to study adobe blocks mechanical properties based on soil-cement reinforced with cellulose fibers obtained from Kraft paper recycling. The bricks were confectioned with 7% Portland cement content and with 0%, 8%, 10% e 12% Kraft paper fiber addition, being submitted to compressive strength test, water absorption test, durability test with wetting and drying and retraction analysis. It was verified the confectioned composites presented as a viable and interesting alternative on technical and environment range. All studied researches presented null retraction and compressive strength increase on cracked state, toughness increase and good performance about durability.

Development of qualitative properties and surface modification of mixed recycled 70% old newspaper and 30% old magazine pulp after enzymatic treatment with commercial cellulase was evaluated. The results of the present research demonstrated that the quality of the pulp and paper obtained from cellulase deinking process was comparable or even better than that from the chemical deinking. Under mild conditions of cellulase deinking (charge of 0.025–0.1% and duration time of 20 min, the paper with similar opacity as well as the increased brightness and whiteness values were obtained in comparison with non treated pulp or chemical one. Increasing reaction time to 30 min (at higher levels than 0.25% cellulase) and also enhancing the charge of cellulase to more than 0.1% (at different reaction times) were not advisable due to weak optical features of paper produced. The highest deinking efficiencies of 11.77 and 10.04% were obtained in enzymatic runs with cellulase (C2T2 and C1T3, respectively) but it was 9.3% for chemical deinking process (run of Cc). Increase in duration from 10 to 30 min at the maximum cellulase charge (0.2%) has been negatively influenced tensile index, breaking length, stretch and stiffness. In general, the best strength properties were obtained at middle charges of cellulase (0.025–0.05%) and duration times of 10–20 min. All strength characteristics were severely declined for run C4T3 (charge 0.2% and reaction time of 30 min). Run of C3T2 (charge 0.1% and reaction time of 20 min) was resulted in the higher tensile index (by 22%), stretch (by 9%) and stiffness (by 42%) compared to chemically deinked pulp. Cellulose crystallinity obtained by FTIR and XRD spectra was remarkably increased up to 0.2% cellulase but reduced severely at higher charges than 0.2% cellulase which implied declining the strength properties. In addition, FESEM micrographs of recycled fibers treated at different cellulase charge and duration times revealed surface modification and morphological changes like external fibrillation, peeling, fine production as well as rougher fiber surface due to cellulase act on the fiber surface. With increasing enzyme charge and duration time to some extent, fiber fibrillation have been developed and appearing much fibrils may result in the increased hydrogen bonding, number and contact area between fibers and consequently paper strength properties. However in harsh conditions particularly higher cellulase charges, the fiber structure is degraded, more fines appeared on fiber surface and strength properties are declined (especially tear resistance) due to a possible reduction in average fiber length.

The emphasis of the current study was on the calcination of lime sludge, performed at different temperatures from 650°C to 750°C, which consumes less energy as compared to the industrial pr...

The widespread availability of banana pseudo stems which do not have considerable commercial value in the country presents a potential source of non-wood raw material for paper production. This investigation determined the suitability of using banana fiber for wrapping paper production. Banana fiber was used with sugarcane bagasse and wastepaper to produce paper in 20:80, 40:60, 60:40 and 80:20 ratios. Banana and sugarcane bagasse were chemically pulped using 12% NaOH and 4% Na2S for 1.5 h. The mean thickness of the papers were 0.263 ± 0.04 mm. 100% banana paper and 100% bagasse paper showed nearly similar water absorbency (2.15 s and 2.17 s) and were 2.25 times more than paper from 100% wastepaper. Highest tensile index was evidenced by banana paper with 20% wastepaper (29.4 Nm/g). For banana-bagasse mix-ratios, 20% bagasse demonstrated highest tensile index (16.04 Nm/g). 100% banana paper produced a tensile index of 18.97 Nm/g. Highest bursting index was from banana paper with 20% wastepaper mix (2.00 kPa m2/g). For banana-bagasse mix-ratios, 20% bagasse addition showed the greatest bursting index (0.88 kPa m2/g). 100% banana paper produced a burst index of 1.05 kPa m2/g. Highest abrasion resistance was 180 turns which was demonstrated by 100% banana paper. 20% mix bagasse and 20% mix wastepaper demonstrated the greatest abrasion resistance with 136 turns and 120 turns respectively. 20 40% of wastepaper (5.4 5.8% weight loss) and 10 30% bagasse (10.0 15.5% weight loss) were categorised as optimal mix percentages in the pulp mix for their minimal weight losses.

Paper electronics is an emerging technology to implement flexible and wearable electronics devices via ink printing process. This paper evaluates the feasibility of using conventional printing paper for coating process with graphene/cellulose ink. 4 different types of regularly used conventional printing papers were used as substrates in this work. The conductive graphene ink was prepared through exfoliation of graphite in cellulose solution. The paper substrates surface morphology and sheet resistance of the drop-casted conductive ink on each paper were analyzed and discussed. Glossy paper was found to be suitable paper substrate for the printing of the formulated ink due to its low surface roughness of 16 nm. The value of sheet resistance of the graphene/cellulose thin film can be lowered to 4.11 kΩ/sq by applying multiple drops. This work suggests that conventional printing paper may offer solution for highly scalable and low-cost paper electronics.

The use of vegetable oil (natural ester) in electrical devices like power transformers is increasing due to their high biodegradability and better safety. The lifespan of power trans- formers is mainly defined by cellulose insulation condition, which usually works together with dielectric oil as electrical insulation and also as mechanical winding protector and compactor. That is why the aim and results of this research shows us not only the dielectric parameters evolution, but also the relationship between the mechanical factors and the moisture content of thermal accelerated ageing processes, with commercial vegetable oil, of Kraft paper and Diamond Dotted Paper (DDP). These are two of the most common insulating materials in electric power transformers. In addition, the new tests have been done by a different method of paper ageing analysis. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement Nº 823969 - BIOTRAFO.

The solid waste accumulation from industries is becoming the cause of environmental concerns. Millions of tons of lime sludge are generated by the Pulp and paper and other industries all over the world. For the reduction of the solid waste threat to the environment, its application as a raw material in other industries could be the suitable option. In this study, lime sludge from recovery section of the paper mill is used in mortar in its as-received condition and in calcined condition to partially substitute cement. Calcination of lime sludge is performed at the relatively lower temperature of 650–750 °C, which takes less energy input than the industrial process of calcination. The M25 grade of mortar is prepared, with the substitution of cement by as received lime sludge in the range of 10, 20, 30 and 40% by weight. These blends of mortars are also prepared with calcined lime sludge. Produced mortar mixtures are tested for compressive strength and also compared with conventional mortar. Compressive strength is evaluated with 7, 28 days of curing. As a result, the compressive strength of mortar with as received lime sludge, match with the M25 grade of mortar up to 10% addition of lime sludge, after that compressive strength of mortar decreased with the further addition of lime sludge. Mortar blends with calcined lime sludge achieved the M25 grade compressive strength till 30% replacement of cement in mortar blends. Lime sludge after calcination produced more compressive strength in mortar than as received lime sludge due to the presence of reactive lime and pozzolanic materials. This study helps in developing the sustainable utilization of large amount of lime sludge, produced from paper industries ended up in landfills.

Lipase enzyme has a critical role in deinking process along with other lignocellulosic enzymes. In this paper, we try to demonstrate the role of lipase in the enzyme cocktail used for enzymatic deinking. For this, we identified a potential lipolytic bacterium, Pseudomonas mendocina ED9 isolated from elephant dung with a molecular weight of 35 kDa. During the Box-Benhken model optimization, a maximum lipase activity of 105.12 U/g, which was 12.36-fold higher than the initial enzyme activity and 1.3-fold higher than the activity obtained during the Plackett Burman design, was achieved. A maximum lipase activity of 105.12 U/g was obtained after optimization. Ammonium sulphate (60%) precipitation resulted in a specific activity of 68.19 U/mg with a 1.4-fold purification and yield of 64%. Lipase from P. mendocina ED9 exhibited a Km of 0.5306 mM and Vmax of 25.0237 μmol/min/mg. A Δ brightness of approximately 14.5% were achieved during the enzymatic deinking using cocktail comprised of cellulase, xylanase and lipase. This reports the significant role and efficacy of lipase in enzyme cocktails for deinking applications. This formulation will reduce the pollution and environmental toxicity of conventional chemical deinking.

Super-flexible, electrically and thermally conductive graphene-based papers are in great demand in the fields of electronics and supercapacitors. However, the applications of graphene-based papers are limited either by their brittleness, small scale, or by their unsatisfactory thermal conductivity. Conventionally, such papers are fabricated by vacuum-assisted filtration, direct evaporation, electrospray coating, or wet spinning. Here we propose a novel strategy, namely, direct densification of reduced graphene oxide foam, to fabricate large-scale multifunctional graphene papers. The graphene paper density could be adjusted by applying different loads. The densities of the graphene papers varied from 0.32 g cm−3 to 1.85 g cm−3. The thermal conductivity, tensile stress, electrical conductivity and electromagnetic interface shielding effectiveness increased with an increase in the density of the graphene paper. When the density of the graphene paper reached 1.85 g cm−3, the tensile stress was up to 50.4 MPa with strain of 4%, the thermal conductivity was 1103 W m−1 K−1 at room temperature and there was high electrical conductivity of 1.1 × 105 S m−1, as well as an electromagnetic interference (EMI) shielding effectiveness of 77.2 dB. Our new strategy is very promising in terms of controlling the thickness, density, and size of graphene paper. Our graphene paper has very high potential for applications.

Organosolv lignin was used as stabilizer to synthesize Bentonite-Lignin nano zero-valent iron (BL-nZVI). Then FTIR, XRD, SEM and TEM were carried out to characterize this new material. Results proved that organosolv lignin can effectively prevent the aggregation of nano zero-valent iron particles. BL-nZVI was applied as particle electrodes and formed a three-dimensional (3D) electrode system with ruthenium/iridium coated titanium plates and acted as tertiary treatment process to dispose the pulp and paper secondary wastewater. The removal efficiency of the chemical oxygen demand (COD) and color of the effluent were selected as indicators to check the performance of the system. It was found that the removal efficiency of COD and color depended on the current density, electrolysis time, distance of electrode plates, initial pH value and particle electrode dosage. The optimal parameters of each factor were also determined by a series of single factor experiments. Under the optimum conditions, removal efficiency of COD and color can reach 87.6% and 93.1% respectively. Possible mechanism of the 3D electrode system with BL-nZVI particle electrodes for treatment of pulp and paper wastewater was also proposed.

A high quality graphene paper has been fabricated using drop-casting of a custom developed stable ink mixture. The graphene/ethyl cellulose mixture can produce graphene paper coating on Kapton substrate at fairly large scales by finely adjusting the viscosity of the ethyl cellulose solvent blend. It was possible to produce a morphologically intact 300 nm-thick stacked structures of high purity graphene platelets after annealing at 300 °C, as characterized by SEM, Raman Spectroscopy and AFM. The electrical resistivity of a large batch of samples was measured and the results thoroughly evaluated, using a design of experiments approach. The resistivity values achieved were found to be lower or comparable to the best results reported in the literature. As expected, resistivity is inherently related to the concentration of the as-prepared ink and subsequent annealing conditions. However, prolonged annealing time can deteriorate mechanical properties as determined by cyclic bending and shear tests. It is anticipated that the present graphene paper has potential use in flexible electronics applications since the lowest resistivity and structure achieved were generally unaffected by the range of mechanical loadings studied.

The correct unit in Table 2 is Lipase activity (U/g).

Reduced graphene oxide (RGO) multilayer sheets were synthesized using waste paper pulp as carbon source. Formation of RGO was confirmed by Raman spectroscopy. RGO was mixed with cement at different concentrations (0.001, 0.01, 0.05 and 0.1% w/w) to obtain graphene cement composites (GCC). RGO is supposed to impart hydrophobicity to cement; hence, the capillary test was conducted. Hydrophobic property of GCC was found to be dependent on time, concentration and temperature. Antimicrobial property of GCC was checked which included antibacterial and antifungal studies. GCC showed better antibacterial performance (90%) against gram positive bacteria (Bacillus subtilis) than the gram-negative bacteria (Escherichia coli, 85%). Gram negative bacteria possess structurally more complex cell membranes than gram positive bacteria; hence, it was more resistant to GCC. Our finding supports the concept of involvement of membrane bound macromolecules in antibacterial performance of RGO. GCC was also found to be effective (88% inhibition) against fungal strain (Aspergillus niger).

The corrosion-resistance properties of modified ultra-thin carbon paper (CP) different graphene oxide (GO) content used in proton exchange membrane fuel cells (PEMFC) are studied for the first time. Results show that CP with 1 wt% GO has distinguished corrosion-resistance property (corrosion current: 5.539E − 8A.cm−2, minimum weight loss and contact angle variation). And mechanism analysis was found that the CP-1GO-P had uniform florine coating on some area of carbon fiber while T-CP-P has little. Moreover, the addition of GO could introduce more C O and C O groups which interact with the florine atom, thus can strengthen the bonding of PTFE and matrix carbon effectively.

Paper mills are currently pressed to reduce costs because of lack of resources and rising oil prices. Accordingly, paper mills are increasing the quantity of low-priced pulp using a ratio with relatively low whiteness by decreasing the use of high-priced, high-quality pulp. To solve the problem of deteriorated whiteness, paper mills regularly use a fluorescent whitening agent. In addition, with the increase of resource recycling and environmental problems, interest is growing in the use of recycled paper, which partially or completely contains recycled pulp. In this study, we investigated the content of hazardous heavy metals in recycled paper and paper stock produced in domestic paper mills and determined if other residues that are harmful to human health are present. Currently, no regulated minimum value is given for fluorescent whitening agents in Korea nor does sufficient research on the toxicity of these agents exist. Determining the amount of ink residue contained in recycled paper as well as the extent of harmful chemical residue resulting from the deinking and bleaching processes is necessary. This research also determined whether other chemicals added when producing recycled paper remained and subsequently analyzed the organic volatile compounds in the recycled paper and the existing produced paper to evaluate risk. We examined the influence of using waste paper on printing properties by performing comparative research on printing quality, e.g., printing color reproducibility of an existing textbook paper and recycled paper containing 30% old paper, trapping, contrast, halftone dot reproducibility, gloss, and rear shining. Test results concluded that fluorescent material, hazardous heavy metals, and the quantity of detected volatile organic material were not present at levels harmful to human health.

Direct coating of Si on an elastic carbon nanotube (CNT) network effectively addresses the rapid capacity fading of the Si anode. However, this strategy is hindered by the low Si tap density (Si < 50 nm) since sufficient void space has to be left for accommodating the Si volume change. Also, the mechanical properties of the CNT network as the elastic buffer matrix degrade significantly caused by side reactions of CNT with electrolyte. This work presents a freestanding paper-like anode consisting of a symmetrical sandwich-structured SiN/Si/SiN composite grown on CNT paper. This anode works well (∼259 μA h cm−2 under the current rate of 0.6C after 350 cycles, with a capacity retention of 73.8%) even when the CNT is filled by the composite without void space left for accommodating volume expansion. This is mainly due to the following synergistic effects: on one hand, the stress-compensation phenomenon in the symmetrical sandwich-structured composite balances the volume change-induced stress and thus the composite has a robust mechanical stability with an intact morphology during cycling. On the other hand, the intact composite avoids reaction of CNT with the electrolyte and thus the CNT retains excellent mechanical properties and serves well as the elastic buffer matrix. These two sides interact with each other, enabling the high anode performance.

Agro-wastes valorization focusses on production of high value-added products, such as cellulose nanofibers (CNF), and contributes to reduce the environmental impact of these residues. CNF have been used successfully as papermaking additives and some previsions maintain that this sector will become the most important, demanding CNF at a reasonable cost. Furthermore, the optimization of the production process of CNF from agricultural residues would contribute to the goals of a circular economy, the development of rural areas and the costs reduction by producing CNF of the minimum quality fit-for-use in recycled paper. In this study, CNF was produced from two agricultural residues; corn (C-CNF) and rape (R-CNF) stalk pulps, pretreated with bleaching, refining and TEMPO-mediated oxidation. Coagulant and cationic polyacrylamide (dual system) and chitosan were the retention systems. Results show the difficulty of predicting the effect of CNF based on their properties, as fibrillation degree or anionic charge, on the improvement of mechanical properties of recycled paper. That is proved by the low differences in tensile index (TI) improvement (∼15% by adding 0.5% C-CNF combined with dual system), obtained with CNF with very different properties. The expensive TEMPO pretreatment could be avoid by applying bleaching pretreatment to the corn pulp, increasing the TI up to 15% without affecting drainage and decoupling the simultaneous deterioration of drainage with TI improvement (drainage time decreased nearly 50% and 20% adding bleached R-CNF and C-CNF, respectively, combined with chitosan). Similar improvements on TI can be achieved by replacing the dual retention system by chitosan without addition of CNF, but the combination of CNF and chitosan allows achieving the highest TI values.

Demands of thermal recording paper have been increased significantly by increase in us-age of invoice, fax, and label. Thermal recording paper was mainly made based on virgin fiber. It is necessary to find a suitable alternative to virgin fiber in terms of environment protectional resources conservation. In this paper, deinking properties of different recov-ered papers were analyzed in order to use the recovered paper as raw material of thermal recording paper. Recovered paper were ONP, OMG and white ledger. Flotation reject of OMG was high because inorganic pigments in coating layer could be removed by upstream of froth. Brightnessof white ledger and OMG were much higher than that of ONP. Therefore, properties of pulp made from the recovered paper could be enhanced with increase in blending ratio of white ledger and OMG. However, blending ratio of OMG caused the increase of flotation reject. Consequently, the optimum blending ratio of ONP, OMG, and white ledger was 3:3:3 for eco-friendly thermal recording paper. Under the condition, brightness was about 70% and ERIC was below 300 ppm. Keywords: Deinking, thermal recording paper, flotation, old newspaper, white ledger, old magazine

Coating of the paper surface against to microorganism to making it suitable for food packaging is crucial in terms of improving antimicrobial properties. Cuminum cyminum L. known as cumin and Prunus mahaleb L. have the abundant chemical compound. Cumin has antiviral activity that making it proper for coating due to its various components. Mahaleb as well has rich fragrance make it eligible for sugary snacks and chocolate package. After coating with such biomaterials, thanks to varied fatty acids impart protective feature from oxidation to paper surface. It was observed that the odor of substances was trapped from paper samples. Wrapping paper selected as a base paper in this study. Cationic starch used for emulsifying the coating chemical. Cumin and mahaleb added the starch emulsion and coating suspension applied on the top pile of the paper with # 0 drawdown bar. Coating application reduced the paper's tear index results but increase tensile and burst index results in both cases. Mahaleb gives better Cobb60 value and bursting and tensile index and comparing to Cumin. However, cumin coated papers tensile index results in machine direction was better than mahaleb. Both natural substances are suitable material as an additive to the coating.

Laccase has the enormous potential to be implemented as the multitasking biocatalyst in whole process of paper making. The enzyme can utilize effectively for pulping, delignification of pulps as alone or in the combination with other bleaching enzymes. Laccase has been evaluated for the biografting of pulp fibers, decolorize and stabilize the effluent of the paper mills, biotransformation of high molecular weight (HMW) lignins to lower molecular weight (LMW) aromatic compounds. Further this enzyme has the huge possibilities to apply for deinking of old newsprint (ONP) and pitch removal from varieties of the different pulps. There is no doubt on versatility mode of action of laccases in paper industry, but still there is limited commercialization of this enzyme has been possible, because of laccases has the less redox potential (E0) and needs mediators for the oxidation of non phenolic substrates, production of enzyme is cost intensive at large scale. This review is providing the proper updated information on the state of the art of different applications of laccase in paper industry. It also confer the interpretation to the readers about the areas of extensively studied and the field where there is still much left to be done.

In recent years, there is an increase in global industrial utilization of wastepapers in the production of new one in which pulp and paper industries become one of the largest consumers of wood. Human needs result in harvesting of more trees with waste accumulation for proper disposal, which is a threat to global warming. The application of enzymes in deinking of recovered wastepapers is the major potential enzymatic applications in pulp and paper industries. Enzymes from either bacteria or fungi such as cellulase, xylanase, hemicellulase, pectinase, laccase, amylase, and lipase can be used to deink office wastepapers by enzymatic discharge of the ink particles from fiber surface or hydrolysis of the ink carrier. The lignifying enzymes and others being eco-friendly in nature hence provide a substantial way out to lessen the burden of employing toxic bleaching agents and other chemicals, thus helping in reducing deforestation and the release of harmful treatment effluents and correspondingly improving the quality and brightness of the bleached pulp. In this chapter, critical studies on the applications of microbial enzymes used for deinking of wastepapers in pulp and paper industries were examined.