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We present how harmful different wood extractives carried over to paper mill with unbleached softwood Kraft pulp are for the strength of packaging papers and boards. The investigations were done by simulating industrial papermaking conditions in laboratory-scale trials for handsheet production. It was found that fatty acids are the most relevant compounds in the carryover pitch extractives (CPEs), as they readily interfere in fiber–fiber bonding strength, control the properties of CPE micelles, and are furthermore the most abundant compounds. Addition of cationic starch improved strength and evened out the strength differences of handsheets with different CPE compounds. Oleic acid (unsaturated fatty acid) was an exception, as it was above average harmful for paper strength without cationic starch and also heavily impaired the functioning of cationic starch. As a whole, these findings demonstrate that fatty acids, especially unsaturated ones, are the most relevant CPE compounds contributing to the reduced efficiency of cationic starch and decreased strength of unbleached softwood Kraft paper. This makes the cleaning of process waters by precipitating CPEs on the pulp fibers harmful for paper strength.

The aim of this work is to obtain better water resistance properties with additives to starch at the size press. A further goal is to replace petroleum-based additives with environmentally friendly hydrophobic agents obtained by derivatization of wood rosin. A crude wood rosin (CWR) sample was methylated and analyzed with gas chromatography-mass spectrometry (GC-MS). Methyl abietate, dehydroabietic acid, and abietic acid were the main constituents of the sample. The crude wood rosin samples were fortified with fumaric acid and then esterified with pentaerythritol. Fortified and esterified wood rosin samples were dissolved in ethanol and emulsified with cationic starch to make them suitable as hydrophobic additives for surface treatment formulations in mixtures with starch. These hydrophobic agents (2% on a dry weight basis in a cationic starch solution) were applied to paperboard, bleached kraft paper, and test liner paper using a rod coater with a target pickup of 3-5 gsm. The solution pickup was controlled by varying the rod number. The amounts of hydrophobic material applied in the preparation of the paper samples were 32.2, 48.6, and 35.1 lb/ton pickup compared to three types of base papers. Basic surface features of fortified and fortified and esterified rosin-treated paper were compared with base paper and paper treated with starch alone. Lower Cobb(60) values were obtained for fortified and esterified samples than for linerboard samples that had been surface-sized just by starch. Thus, as novel hydrophobic additive agents, derivatives of CWR can be a green way to increase hydrophobicity while reducing starch consumption in papermaking.

The functional design of paper-based material surfaces with renewable functions and environmentally friendly properties is prevalent nowadays. Herein, a superhydrophobic surface with a coral reef-like structure was prepared on filter paper by electroless copper plating, rapid silver nitrate etching, and facile 1-hexadecanethiol impregnation. After low-surface-energy thiol treatment, this unique coral reef-like structure surface showed excellent superhydrophobicity with a water contact angle of 163.8° and superoleophobicity with an oil contact angle of 0°, which could be used for oil-water separation and had a separation efficiency above 89.17% after 12 consecutive oil-water separations. Because the copper layer and silver nanostructure are both excellent conductive materials, the modified paper exhibited excellent electromagnetic shielding properties, and the electromagnetic interface shielding effectiveness exceeded 63 dB from 9 kHz to 1.5 GHz. The modified paper also had excellent self-cleaning properties and a better corrosion resistance. The unique three-dimensional interweaving structure between the cellulose fibers in the filter paper is fully utilized, and the substitution reaction between the silver ion and the copper coating produces a coral reef-like structure, which provides a new strategy for promoting the wide application of paper-based materials.

Controlling the size and rigidity of calcium carbonate became possible. HCCs were developed and manufactured by the in situ reaction of carbon dioxide and calcium oxide, which were already preflocculated together with GCC using ionic polymers before the reaction. HCC is deformable under pressure during the papermaking process, and its degree of rigidity can be controlled by adjusting the fraction of calcium oxide. The size of HCC can be further controlled by adjusting shearing force. The more the fraction of calcium oxide, the more rigid the HCC and the smaller the diameter of the HCC. When used in papermaking, HCC increased the tensile strength and bulk of paper simultaneously without lowering other essential paper properties, and its deformable nature under pressure improved paper smoothness. Saving chemical pulp by 10% by replacing it with HCC, which is 3–4 times less expensive than the chemical pulp, was demonstrated successfully without lowering the essential properties of paper. Implementation of HCC in the paper mill may result in saving chemical pulp, drying energy, and production cost. The paper mill may utilize the carbon dioxide from the mill stack after purification for HCC preparation.

Reduced graphene oxide (rGO) is an ideal candidate for the improvement of supercapacitor (SC) performances due to its industrial-ready manufacturing process and ease of processing. In this work, rGO was used as an active binder for the manufacture of carbon black (CB) and rGO-based SCs. Being able to form a stable suspension in water, graphene oxide (GO) was initially exploited as a dispersing agent to fabricate a homogeneous slurry with CB having exclusively water as a low-cost and environment-friendly solvent. After casting on a suitable substrate, the material was subjected to thermal treatment allowing the reduction of GO to rGO, which was successively confirmed by chemical–physical analysis. An innovative current collector, consisting of high-quality rGO paper, was also proposed ensuring an improved adhesion between the active material and the substrate and a reduction of the whole weight with respect to devices fabricated using common metallic current collectors. Due to the interesting electrochemical performances, with a high specific power of 32.1 kW kg–1 and a corresponding specific energy of 8.8 Wh kg–1 at a current of 1 A g–1, and the improved manufacturing process, the described “all-graphene-based” device represents a valuable candidate for the future of SCs.

In this work, a high-performance sensor capable of effectively detecting nerve gas, a type of chemical warfare agent, was realized by conductive paper with polyaniline (PANI) nanofiber and graphene...

Novel paper-based potentiometric platforms for rapid, cost-effective, and simple determination of the salicylhydroxamic acid (SHAM) drug are presented. Both the SHAM sensor and the reference Ag/AgCl electrode were integrated together on the miniaturized paper platforms. The ion-sensing membrane for the presented sensor is based on the use of SnIV-tetraphenylporphyrin (SnIVTPP) as a charged carrier within a plasticized poly(vinyl chloride) (PVC) matrix. Multiwalled carbon nanotubes (MWCNTs) were used as an ion-to-electron transducer. The resulting sensor revealed a rapid and stable response with a Nernstian slope of −59.3 ± 0.7 mV/decade over the linear range of 1.0 × 10–6 to 1.0 × 10–3 M and a detection limit of 0.7 μM. All measurements were carried out in 30 mM phosphate-buffered solution (PBS) at pH 7.2. Intra- and interday precision were measured and found to be 1.7%. The relative standard deviation (RSD%) ( = 5) was calculated as 2.43% after utilizing five different electrodes (n = 5). The selectivity behavior of the prepared electrodes in the absence and presence of ionic additives was evaluated. The selectivity pattern showed a non-Hofmeister selectivity pattern in the existence of anionic additives with enhanced potentiometric selectivity for SHAM over different lipophilic anions (e.g., ClO4–, SCN–, and I–). The presented device was successfully applied for SHAM determination in pharmaceutical preparations. This paper-based analytical device can be potentially manufactured at large scales and provides a portable, rapid, disposable, and cost-effective analytical tool for measuring the SHAM drug.

In this study, blue-emission carbon dots were prepared from the legumes of the vegetable Pisum sativum Linn. by one-step carbonization. The fluorescence of a carbon dot (CDs) solution can be quenched by copper ions and recovered by ethylenediaminetetraacetic acid (EDTA). In addition, two kinds of visual fluorescent filter papers were prepared. Finally, a dual-mode fluorescence and visual fluorescent test paper was employed for the detection of copper ions and EDTA. The simple synthesis method and the high safety enable this material to have more application possibilities.

In this study, the potential regulatory effects of fulvic acid extracted from paper mill effluent (PFA) in apple replant disease (ARD) were investigated through a comprehensive experimental evaluation of the effects of PFA on soil properties, growth inhibition of apple replant pathogens, and growth of replanted Malus hupehensis Rehd. seedlings. PFA with a relatively lower molecular weight was mainly composed of carbohydrates, lignin derivatives, and polysaccharides and was rich in functional groups such as carboxyl and phenolic hydroxyl groups. Treatment with PFA dosages ranging from 2 to 3 g/pot significantly increased available phosphorus (P) in soil by 47.5 to 57.5% when compared with the control without PFA, indicating that PFA had a positive effect in activating P. In addition, PFA stimulated the growth of replanted seedlings by promoting root elongation, enhancing leaf photosynthesis, and increasing the activity of root antioxidant enzymes including superoxide dismutase, peroxidase, and catalase. However, no convincing evidence was found that application of different dosages of PFA had remarkable effects on soil pH, inorganic nitrogen, available potassium, organic matter, and the numbers of bacteria and fungi. Notably, PFA had no effect on the copy number of the main pathogenic fungi causing ARD, including Fusarium oxysporum, Fusarium solani, Fusarium proliferatum, and Fusarium moniliforme. Overall, PFA can alleviate ARD to a certain extent mainly through its effects on improving the resilience of replanted young seedlings rather than by affecting soil microorganisms or providing nutrients.

Herein, we describe for the first time, the design and fabrication of a novel nicotine paper-based sensor, in which a miniaturized paper reference electrode is integrated for potentiometric measurements. The paper-based sensors were designed using printed wax barriers to define the electrochemical cell and the sample zones. The electrodes were based on the use of the ion association complexes of the nicotinium cation (Nic) with either tetraphenylborate (TPB) or 5-nitrobarbiturate (NB) counter anions as sensing materials for nicotine recognition. A poly (3,4 ethylenedioxythiophene)/poly-(styrene sulfonate) (PEDOT/PSS) conducting polymer was used as an ion-to-electron transducer. The performance characteristics of the proposed sensors were evaluated and it revealed a rapid and stable response with a Nernstian slope of 55.2 ± 0.3 and 51.2 ± 0.6 mV/decade over the linear range of 1.0 × 10-5 to 1.0 × 10-2 M and detection limits of 6.0 and 8.0 μM for [Nic/TPB] and [Nic/NB], respectively. The sensors revealed a constant response over the pH range 3.5-6.5. The designed sensors provided a portable, inexpensive, and disposable way of measuring trace levels of nicotine coming from different cigarettes and in the collected human sweat of heavy smokers. All results were compared favorably with those obtained by the standard gas chromatographic method.

Clean water is one of the sustainable development goals set by the United Nations for 2030. The development of effective but worldwide affordable strategies is essential to guarantee this achievement. Photocatalysis technology fulfills these criteria whenever the photocatalyst is sustainable and nontoxic. In this article, a cellulose-paper modified with a polyamide-titanium dioxide (TiO2) nanocomposite by dip-coating is evaluated to degrade estrogens efficiently under solar light. The study deepens on the synergic combination of the sorptive capacity of the polyamide and the activity of TiO2. The photocatalytic performance was studied under artificial and sunlight in a miniaturized experimental setup (batch of six reactors). Also, the effects of the dispersed/immobilized catalyst, irradiation time, and adsorption evaluation were studied under kinetic conditions. The photocatalyst composition, considering the polyamide (nylon-6) and TiO2 amounts and the dipping cycles, was studied by a response surface methodology, and the reusability of the photocatalytic cellulose-paper was investigated. The LED source provided removal efficiencies of 65, 62, and 52% (for estrone, 17β-estradiol, and estriol, respectively) after 420 min of light exposure. Under sunlight, the efficiency increased up to 99.5% for estrone and 17β-estradiol and 98.5% for estriol after 180 min of irradiation. The sustainable character of the cellulosic substrate, the low toxicity of the nanocomposite ingredients, and its performance under sunlight make the material attractive for in-field application.

Nanoscale polyaniline (PANI) is formed on a hierarchical 3D microstructure carbon nanotubes (CNTs)/carbon fiber paper (CFP) substrate via a one-step electrochemical polymerization method. The chemical and structural properties of the binder-free PANI/CNTs/CFP electrode are characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The specific capacitance of PANI/CNTs/CFP tested in a symmetric two-electrode system reaches 731.6 mF·cm–2 (1354.7 F·g–1) at a current density of 1 mA·cm–2 (1.8 A·g–1). The symmetric supercapacitor device demonstrates excellent cycling performance up to 10,000 cycles with a capacitance retention of 81.4% at a current density of 1 mA·cm–2 (1.8 A·g–1). The results demonstrate that the binder-free CNTs/CFP composite is a strong backbone for depositing ultrathin PANI layers at a high mass loading. The hierarchical 3D microstructure PANI/CNTs/CFP provides enough space and transporting channels to form an efficient electrode–electrolyte interface for the supercapacitance reaction. The formed nanoscale PANI film coaxially coated on the sidewalls of CNTs enables efficient charge transfer and a shortened diffusion length. Hence, the utilization efficiency and electrochemical performances of PANI are significantly improved. The rational design strategy of a CNT-based binder-free hierarchical 3D microstructure can be used in preparing various advanced energy-storage electrodes for electrochemical energy-storage and conversion systems.

We present a systematic study on the fabrication, characterization of versatile, and low-cost filter paper-based surface-enhanced Raman spectroscopy (SERS) substrates loaded with salt-induced aggregated Ag/Au nanoparticles (NPs). These were demonstrated as efficient SERS substrates for the detection of multiple explosive molecules such as picric acid (5 μM), 2,4-dinitrotoluene (1 μM), and 3-nitro-1,2,4-triazol-5-one (10 μM) along with a common dye molecule (methylene blue, 5 nM). The concentrations of the dye and explosive molecules in terms of mass represent 31.98 pg, 11.45 ng, 1.82 ng, and 13.06 ng, respectively. Silver (Ag) and gold (Au) colloidal NPs were prepared by femtosecond laser (∼50 fs, 800 nm, 1 kHz) ablation of Ag/Au-target immersed in distilled water. Subsequently, the aggregated nanoparticles were achieved by mixing the pure Ag and Au NPs with different concentrations of NaCl. These aggregated NPs were characterized by UV-visible absorption and high-resolution transmission electron microscopy techniques. The SERS substrates were prepared by soaking the filter paper in aggregated NPs. The morphologies of the paper substrates were investigated using field-emission scanning electron microscopy technique. We have achieved superior enhancements with high reproducibility and sensitivity for filter paper substrates loaded with Ag/Au NPs mixed for an optimum concentration of 50 mM NaCl.

A hydrosoluble light-sensitive polymer named PSAG (poly-styrenesulfonate acrylic acid glycidyl methacrylate) was synthesized by acrylic acid (AA), sodium 4-styrenesulfonate (SS), and glycidyl methacrylate (GMA). PSAG is used to modify multiwall carbon nanotubes (MWCNTs) with a length diameter between 0.004 and 0.016. An inkjet conductive ink was formed by well-dispersed MWCNTs in aqueous and organic solvents, which could adjust the surface tension and viscosity of the ink. Gas sensors were then fabricated using this conductive ink on a household inkjet printer. The sensors demonstrated good reproducibility and acceptable recovery time (

The study presents the comparative bioelectrochemical treatment of phenol in anodic and cathodic compartments of four identical dual chambered microbial fuel cells (MFCs) with bare and multiwalled carbon nanotube/polypyrrole (MWCNT/PPy)-coated electrodes, respectively. It was observed that systems performing biocathodic treatment of phenol performed better as compared to the systems performing bioanodic treatment. The maximum power densities for bioanodic phenol treatment using bare and coated electrodes were found to be 469.038 and 560.719 mW/m2, while for biocathodic treatment, they were observed to be 604.804 and 650.557 mW/m2, respectively. The MFCs performing biocathodic treatment of phenol consistently showed higher chemical oxygen demand removal efficiency, Coulombic efficiency, and power density and indicated the better performance of the biocathodic bare (B-MFC) and coated (C-MFC) MFCs as compared to the bioanodic B-MFC and C-MFC. UV/vis spectrophotometry revealed that the MWCNT/PPy-coated carbon paper worked significantly better in the treatment of phenol with admirable treatment obtained within a week of the experiment as compared to the system with bare carbon paper. Cyclic voltammetry asserted better electrochemical activity of the MFC systems with coated electrodes in the treatment of phenol. The electrochemical impedance spectroscopy data also supported the better performance of biocathodic phenol treatment with lower internal and charge transfer resistances. The scanning electron microscopy images confirmed the active biofilm formation on the electrode surface. The study indicates MFC as a viable option for the treatment of recalcitrant chemical compounds with energy recovery.

Reagent-deposited pieces of paper were characterized by the use of a compact conductometer, a compact pH sensor, and a conventional spectrophotometer to assess their suitability for use as reagent containers. The pieces of paper were fabricated by wax printing to form a limited hydrophilic area to which a consistent volume of an aqueous reagent could be added. The pieces of paper without the reagent increased the conductivity of water gradually because of the release of sodium salts, whereas pH of NaOH decreased because of the acidity of the functional groups in the paper. Three reagents, sulfamic acid as an acid, Na2CO3 as a base, and BaCl2 as a metal salt, were deposited on the pieces of paper to evaluate their ability to release from the pieces of paper. Sulfamic acid and Na2CO3 were released in quantities of 58 and 73% into water after 420 s, whereas 100% of BaCl2 was released after 480 s. The conductometric titrations of NaOH, HCl, and Na2SO4, and the spectrophotometry of Fe2+ were examined using the pieces of paper that contained sulfamic acid, Na2CO3, BaCl2, and 1,10-phenanthroline. Titrations using the pieces of paper suggested that the reagents were quantitatively released into the titrant, which resulted in a linear relationship between the endpoints and the equivalent points. In 120 s of soaking time, 60–70% of the reagents were released. The spectrophotometric measurements of Fe2+ indicated that when an excess amount of the reagents was deposited onto the pieces of paper, they nonetheless sufficiently fulfilled the role of a reagent container.

A superior electrical conductivity of 38.5 S/cm and an electromagnetic shielding (EMS) effectiveness of −30 dB (−545 dB/mm) across a wide frequency range of 0–15 GHz, including the X-band, were achieved with thin organic paper of (55 μm) cellulose nanofiber (CNF)/polyaniline (PANI) doped with (±)-10-camphorsulfonic acid nanohybrid. Both electrical conductivity and EMS effectiveness of the PANI-coated CNF were strongly affected by the amount and type of dopant, which could be tunable after fabrication process via simple in situ oxidative polymerization of aniline. Flexible and free-standing film was obtained, since CNF provides good mechanical property without diminishing the electrical property of PANI.

Two sensitive and ratiometric fluorescent probes (probe I and probe II) were developed for the detection of fluoride ions. Probe I can detect fluoride ions quantitatively within a range of 0-6 μM and a detection limit of 73 nM, while probe II has a range of 0-40 μM and a detection limit of 138 nM. The test strips from probe I are quickly able to recognize F- (5 min) inside of the F- safety level in drinking water (1.0 mg/L, ∼5 μM) under 254 nm ultraviolet light, and the test strips from probe II quickly recognize F- (12 min) in dangerously high F- levels in water (4.0 mg/L, ∼21 μM) under 254 nm ultraviolet light. This combination of fluorescent paper sensors from probe I and probe II can be used as a simple and convenient tool to determine whether water is safe to drink or dangerous.

The energy-saving anode with low oxidization potential has been an intriguing pursue for earth-abundant seawater electrolysis. In this paper, we first introduced a superior energy-saving carbohydrazide oxidization reaction catalysis system in the anode section, which can be driven by commercial graphite paper with good durability. Combining this catalysis reaction and common graphite paper, the lowest anodic potentials 0.63 V (vs RHE) and 1.09 V (vs RHE) were obtained for driving a 10 mA/cm2 current density in alkali and near-neutral seawater electrolytes, respectively, outperforming all the as-reported alkali or near-neutral seawater catalysts accordingly to the best of our knowledge.

Paper-based materials are highly desirable as packaging materials due to their numerous advantages that include low cost, renewability, and biodegradability. However, their hydrophilicity has limited their range of applications. Reported herein is a facile and economical approach for the preparation of biodegradable water-resistant paper for food-contact applications. Commercial printing paper and cup papers are coated with melamine, which is FDA approved for food-contact applications. Subsequently, a water-repellent outer layer is applied using poly(dimethylsiloxane) (PDMS)-isocyanate. A relationship between the PDMS concentration and water contact angles (WCAs) of the obtained coating was studied. Typically, the coated cup paper and printing paper had coating loadings of 1.61 ± 1.10 and 0.93 ± 0.74 wt %, respectively. After the coatings had been applied, the WCAs were very high (>125°), and water absorption had decreased by 70% for printing paper and by 35% for cup paper. Considering the facile fabrication method and the low-cost food-safe raw materials, herein, this approach will have great potential for the large-scale production of materials for use in food- and nonfood contact applications.

In order to solve the uneven distribution of copper sulfide nanocrystals (CuS-NCs) on cellulose nanofibers (CNFs), this work reports a feasible method to in situ precipitate CuS-NCs on CNF by utilizing biopolymers (lignin, xylan, or starch) as stabilizer and adhesive for fabricating the multifunctional composite papers. In the presence of biopolymers, CuS-NCs deposited in situ on CNF could be capped and stabilized by the biopolymers molecular chains for uniform distribution. Subsequently, biopolymers could anchor CuS-NCs on CNF by the hydrogen bonding. Compared to the composite paper with lignin or xylan as stabilizer and adhesive, CuS-NCs/starch/CNF paper showed the highest content and most uniform and continuous distribution of CuS-NCs, which not only enhanced the conductivity of composite paper to 10.12 S/cm but also increased the reaction rate constant on photocatalytic degradation of rhodamine B to 0.317 min–1. The reaction rate constant is higher than most of the other reported CuS photocatalysts to date. It indicates that our method has a potential to be a novel strategy to precipitate nanocrystals uniformly on cellulose fibers for fabricating the multifunctional composite paper.

International audience; In the current study, we introduce photothiol-X chemistry as a powerful method to create hydrophobic patterns covalently grafted to the surface of cellulose paper. The general strategy builds on the use of a cellulose-based molecular printboard featuring disulfide functions which upon spatiocontrolled light irradiation at 365 nm allows robust photothiol-X ligations with hydrophobic moieties. A screening of structurally diverse molecular architectures as hydrophobic coating was conducted, and the most impressive result obtained with cholesterol moieties allows the creation of spatially well-resolved hydrophobic patterns with a contact angle of 140.8°. Our discoveries are supported by in-depth characterization studies using Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry, and scanning electron microscopy analyses.

We report a simple approach to fabricate a pyridinic-N-doped graphene film (N-pGF) without high-temperature heat treatment from perforated graphene oxide (pGO). pGO is produced by a short etching treatment with hydrogen peroxide. GO perforation predominated in a short etching time (∼1 h), inducing larger holes and defects compared to pristine GO. The pGO is advantageous to the formation of a pyridinic N-doped graphene because of strong NH3 adsorption on vacancies with oxygen functional groups during the nitrogen-doping process, and the pyridinic-N-doped graphene exhibits good electrocatalytic activity for oxygen reduction reaction (ORR). Using rotating-disk electrode measurements, we confirm that N-pGF undergoes a four-electron-transfer process during the ORR in alkaline and acidic media by possessing sufficient diffusion pathways and readily available ORR active sites for efficient mass transport. A comparison between Pt/N-pGF and commercial Pt/C shows that Pt/N-pGF has superior performance, based on its more positive onset potential and higher limiting diffusion current at −0.5 V.

In this paper, we report the synthesis and characterization of pyrolyzed lignin compacts reinforced with 50 wt % wheat straw (WS) or sugar beet pulp (SBP) fibers. The compacts were pyrolyzed at 300, 500, 700, and 900 °C in an Ar atmosphere. Detailed thermogravimetric analysis (TGA), thermomechanical analysis (TMA), Fourier transform infrared (FTIR) spectroscopy, and microstructure analysis were performed on these samples. FTIR analysis showed that pyrolysis of lignin-WS and lignin-SBP resulted in aromatic char. Scanning electron microscope (SEM) studies showed that foams obtained by pyrolyzing both lignin-50 wt % SBP and lignin-50 wt % WS composites have a cellular structure. X-ray tomography and energy-dispersive spectrometry (EDS) studies showed that pyrolysis of wheat straw caused the formation of mineral-rich nodules in the pyrolyzed lignin matrix, which was responsible for the denser and uniform microstructure of the lignin-WS composites. Due to this reason, the lignin-WS composites were denser and had a better mechanical strength as compared to the lignin-SBP composites. Both the compositions also showed temperature-dependent wettability behavior.

Microbial endoglucanases belonging to the β-1–4 glycosyl hydrolase family are useful enzymes due to their vast industrial applications in pulp and paper industries and biorefinery. They convert lignocellulosic substrates to soluble sugars and help in the biodegradation process. Various biocomputational tools can be utilized to understand the catalytic activity, reaction kinetics, complexity of active sites, and chemical behavior of enzyme complexes in reactions. This might be helpful in increasing productivity and cost reduction in industries. The present review gives an overview of some interesting aspects of enzyme design, including computational techniques such as molecular dynamics simulation, homology modeling, mutational analysis, etc., toward enhancing the quality of these enzymes. Moreover, the review also covers the aspects of synthetic biology, which could be helpful in faster and reliable development of useful enzymes with desired characteristics and applications. Finally, the review also deciphers the utilization of endoglucanases in biodegradation and emphasizes the use of diversified protein engineering tools and the modification of metabolic pathways for enzyme engineering.

Levulinic acid (LA) recently has attracted much attention as a promising biorefinery platform due to its potential to be economical and sustainable. This paper addresses technical, techno-economic, and exergetic analyses of an industrial LA production via acid-catalyzed dehydration. The process was simulated through Aspen Plus, considering a processing capacity of 15,175.60 kg/h of banana empty fruit bunches. The global productivity yield was 25.56%, producing 3883.13 kg/h of LA. The techno-economic analysis evidenced that this process may be an attractive alternative for biomass valorization, considering the obtained financial results. This process's total production cost was 0.178 $USD per kilogram of biomass and a total annualized cost of $USD 29,163,638.95. Exergy analysis revealed that this process had an irreversibility rate of 1.48 × 105 MJ/h. The pretreatment stage presented the lowest exergetic efficiency. Globally, the exergy efficiency was 53.76%, which is within the reported results for analogous biomass transformation processes.

In this study, soybean straw (SS) as a promising source of glycolaldehyde-rich bio-oil production and extraction was investigated. Proximate and ultimate analysis of SS was performed to examine the feasibility and suitability of SS for thermochemical conversion design. The effect of the co-catalyst (CaCl2 + ash) on glycolaldehyde concentration (%) was examined. Thermogravimetric-Fourier-transform infrared (TG-FTIR) analysis was applied to optimize the pyrolysis temperature and biomass-to-catalyst ratio for glycolaldehyde-rich bio-oil production. By TG-FTIR analysis, the highest glycolaldehyde concentration of 8.57% was obtained at 500 °C without the catalyst, while 12.76 and 13.56% were obtained with the catalyst at 500 °C for a 1:6 ratio of SS-to-CaCl2 and a 1:4 ratio of SS-to-ash, respectively. Meanwhile, the highest glycolaldehyde concentrations (%) determined by gas chromatography–mass spectrometry (GC–MS) analysis for bio-oils produced at 500 °C (without the catalyst), a 1:6 ratio of SS-to-CaCl2, and a 1:4 ratio of SS-to-ash were found to be 11.3, 17.1, and 16.8%, respectively. These outcomes were fully consistent with the TG-FTIR results. Moreover, the effect of temperature on product distribution was investigated, and the highest bio-oil yield was achieved at 500 °C as 56.1%. This research work aims to develop an environment-friendly extraction technique involving aqueous-based imitation for glycolaldehyde extraction with 23.6% yield. Meanwhile, proton nuclear magnetic resonance (1H NMR) analysis was used to confirm the purity of the extracted glycolaldehyde, which was found as 91%.

This article introduces a clean and efficient method for the synthesis of Ti-MWW by utilizing the recycled mother liquor. The effects of titanium and silicon sources on the synthesis of Ti-MWW and the recycling of the mother liquor are discussed in detail. Precipitated silica prepared with Na2SiO3 and CO2 was selected as the silicon source, and TiCl3 was selected as the titanium source. The mother liquor was recycled five times, and the obtained samples showed good catalytic activity in cyclohexanone ammoximation. This work can be conducive to reducing the influence on the environment and economizing on materials for the industrial production of Ti-MWW.

A portion of the lime mud formed during the causticizing process in the recovery process of kraft pulping should be purged from the calcium cycle as waste before it is fed to the lime kiln; this ensures that the quality of the pulp and pulping chemicals is maintained. The discharged greenish-gray lime mud, which is often disposed as an industrial waste, has been transformed herein into a high-quality papermaking filler via the hybrid calcium carbonate (HCC) and post-HCC (pHCC) technology. Initially, the lime mud was heat-treated and then ground to small-size particles. The ground lime mud was preflocculated with calcium oxide by ionic polymers, and carbon dioxide was injected to the flocs to produce lime mud HCC (LHCC). To produce lime mud pHCC (pLHCC), only the ground lime mud was preflocculated first, calcium oxide was added next, and finally, carbon dioxide was injected to the flocs. The resultant products, LHCC and pLHCC, gave brightness as high as that of the ground calcium carbonate (GCC) in paper while a little higher brightness for pLHCC than for LHCC. They also enabled to increase bulk, stiffness, and tensile strength. Application of the LHCC and pLHCC technology to the lime mud could save waste disposal expenses and produce better-quality paper.

This paper deals with the innovation of the Czech colorimetric biosensor Detehit designed for the simple, fast, and sensitive detection of nerve agents. The innovation is based on the use of an indicator consisting of a mixture of two triphenylmethane dyes, Guinea green B and a basic fuchsin, on a glass nanofiber filter paper carrier. The advantage of this solution is the blue–red color transition, which is much more visible than the white–yellow transition of other Detehit biosensors. The newly designed biosensor allows the users to visually detect (with the naked eye) the presence of the most significant paralytic substances (sarin, soman, cyclosarin, tabun, VX) in water at concentrations of at least 0.001 μg/mL. This biosensor design also enables one to detect these substances in air or on contaminated surfaces.

Biomass renewable energy has become a major target of the Thailand Alternative Energy Development Plan (AEDP) since the country’s economy is largely based on agricultural production. Rice husk (RH) is one of the most common agricultural residues in Thailand. This research aims to investigate yields and properties of biochar produced from copyrolysis of RH and plastic (high-density polyethylene (HDPE)) at different ratios, temperatures, and holding times. For both individual and copyrolysis, the temperature variation generated more pronounced effects than the holding time variation on both biochar yields and properties. For individual pyrolysis of RH, the maximum biochar yield of ∼54 wt % was obtained at 400 °C. A shift in temperature from 400 to 600 °C resulted in RH biochars with higher fixed carbon (FC) and carbon (C) contents by ∼1.11–1.28 and 1.06–1.22 times, respectively, while undetectable changes in higher heating values (HHVs) were noticed. For copyrolysis, obvious negative synergistic effects were observed due to the radical interaction between the rich H content of HDPE and RH biochars, which resulted in lower biochar yields as compared to the theoretical estimation based on individual pyrolysis values. However, the addition of HDPE positively impacted the FC and C contents, especially when 10 and 20 wt % HDPE were added to the feedstock. Besides, higher HDPE blending ratios resulted in biochars with improved HHVs, and >1.5 times improvement in HHV was reported in the biochar with 50 wt % HDPE addition in comparison with RH biochar obtained under the same conditions. In summary, biochars generated in this study have the potential to be utilized as a solid fuel or soil amendment.

During hydrocarbon drilling operations, the presence of hydrogen sulfide (H2S) gas could cause serious health and safety issues. Scavenging this gas and eliminating its impact are essential requirements for a safe drilling operation. This study investigated the impact of three H2S scavenger additives (copper nitrate, iron gluconate, and potassium permanganate) on water-based drilling fluids (WBDFs). The additives were tested on two actual field drilling mud samples that differ mainly in their weight. The scavengers' impact on drilling muds was investigated by measuring their scavenging capacity and their effect on rheology, fluid loss, and pH. Potassium permanganate outperformed the other scavengers when added to the lighter (lower density) WBDF. However, it did not impact the scavenging capacity of the heavier mud system. Copper nitrate outperformed the other scavengers in the heavier drilling mud system. Also, the addition of copper nitrate in the lighter mud system increased its H2S-scavenging capacity greatly, while for iron gluconate, it did not perform very well. Overall, all the scavenger-containing drilling muds did not have any significant harmful impact on the plastic viscosity or the fluid loss properties of the drilling muds. Furthermore, all the tested drilling mud samples showed an excellent ability to clean wellbores and suspend drill cuttings evident by the high carrying capacity with the exception of iron gluconate or potassium permanganate with the heavy mud system.

Acetone and n-heptane are common solvents in the pharmaceutical industry and they have been found in wastewater. Under atmospheric conditions, the mixture of these compounds creates a minimum-boiling azeotrope. The extractive distillation process with a high boiling solvent is commonly utilized to separate the azeotropes in the industry to minimize waste, reuse resources, achieve clean production, and preserve the environment. In this work, extractive distillation was applied to separate the binary azeotropic system of acetone and n-heptane in wastewater using butyl propionate as a solvent. The characteristics of the process are designed and simulated via Aspen Plus. The simulation results showed that to get a distillate containing at least 99.5 mass% acetone, a solvent-to-feed ratio of 1.4, a reflux ratio of 1.5, a number of stages of 30, a feed stage of 26, a solvent stage of 10, and a solvent temperature of 298.15 K were required. The optimum operating parameters of the process were also obtained using the NLP optimization method, with the minimum total annual cost as the objective function. While the process was operating in optimal mode, CO2 emissions were calculated to be 0.0780 kg CO2/kg feed.

In this investigation, the relationship between fiber properties and papermaking properties of 22 non-wood materials at the unrefined and refined states was assessed. The fiber length had positive and the cell wall thickness had negative correlation on the strength properties for the refined pulp. The relationship between papermaking properties with pulp quality, such as fines, curl index, kink index, external fibrillation, and coarseness, was also determined. The correlations of multiple regression equations of fiber quality parameters were 70.4% for the tensile index and 84.9% for the tear index for the refined pulp. The correlations of multiple regression equations of chemical characteristics of the samples were 81.9% for the pulp yield and 42.7% for the kappa number. Holocellulose and α-cellulose had a positive and lignin had a negative effect on the pulp yield.

This research was aimed to examine the diesel engine’s performance and emission of secondary fuels (SFs), comprising waste plastic oil (WPO) and palm oil biodiesel (POB), and to analyze their tribological properties. Their compositions were analyzed by gas chromatography–mass spectrometry (GC–MS). Five SFs (10–50% POB in WPO) were prepared by mechanical stirring. The results were compared to blank WPO (WPO100) and Malaysian commercial diesel (B10). WPO90 showed the maximum brake power (BP) and brake torque (BT) among the SFs, and their values were 0.52 and 0.59% higher compared to B10, respectively. The increase in POB ratio (20–50%) showed a negligible difference in BP and BT. WPO70 showed the lowest brake-specific fuel consumption among the SFs. The brake thermal efficiency (BTE) increased with POB composition. The maximum reductions in emission of hydrocarbon (HC, 37.21%) and carbon monoxide (CO, 27.10%) were achieved by WPO50 among the SFs. WPO90 showed the maximum reduction in CO2 emission (6.78%). Increasing the POB composition reduced the CO emissions and increased the CO2 emissions. All SFs showed a higher coefficient of friction (COF) than WPO100. WPO50 showed the minimal increase in COF of 2.45%. WPO90 showed the maximum reduction in wear scar diameter (WSD), by 10.34%, compared to B10. Among the secondary contaminated samples, SAE40-WPO90 showed the lowest COF, with 5.98% reduction compared to SAE40-WPO100. However, with increasing POB content in the secondary contaminated samples, the COF increased. The same trend was also observed in their WSD. Overall, WPO90 is the optimal SF with excellent potential for diesel engines.

The biological reduction of ferrous ethylenediaminetetraacetic acid (EDTA-FeII-NO and EDTA-FeIII) is an important process in the integrated electrobiofilm reduction method, and it has been regarded as a promising alternative method for removing NO x from industrial boiler flue gas. EDTA-FeII-NO and EDTA-FeIII are crucial substrates that should be biologically reduced at a high rate. However, they inhibit the reduction processes of one another when these two substrates are presented together, which might limit further promotion of the integrated method. In this study, an integrated electrobiofilm reduction system with high reduction rates of EDTA-FeII-NO and EDTA-FeIII was developed. The dynamic changes of microbial communities in the electrobiofilms were mainly investigated to analyze the changes during the reduction of these two substrates under different conditions. The results showed that compared to the conventional chemical absorption-biological reduction system, the reduction system exhibited better performance in terms of resistance to substrate shock loading and high microbial diversities. High-throughput sequencing analysis showed that Alicycliphilus, Enterobacteriaceae, and Raoultella were the dominant genera (>25% each) during the process of EDTA-FeII-NO reduction. Chryseobacterium had the ability to endure the shock loading of EDTA-FeIII, and the relative abundance of Chryseobacterium under abnormal operation conditions was up to 30.82%. Ochrobactrum was the main bacteria for reducing nitrate by electrons and the relative abundance still exhibited 16.11% under shock loading. Furthermore, higher microbial diversity and stable reactor operation were achieved when the concentrations of EDTA-FeII-NO and EDTA-FeIII approached the same value (9 mmol·L-1).

Mechanical refining (MR) is a cost-effective pretreatment in biochemical conversion processes that is employed to overcome biomass recalcitrance. This work studied the effects of MR on biogas and methane produced by the anaerobic digestion (AD) of dairy manure. The cumulative gas volume and yield from the AD of manure refined at 6k revolutions increased by 33.7 and 7.7% for methane and by 32.0 and 6.4% for biogas, respectively, compared to the unrefined manure. This enhancement was reached by increasing manure solubilization, reducing particle size, and achieving external fibrillation and internal delamination of fibers in manure. However, the highly refined manure (subjected to 60k revolutions) exhibited methane and biogas yields that were reduced by 9.5 and 1.5%, respectively. This decrease was observed because the pore structure was ruptured, and finely ground manure particles were aggregated together at high revolutions (60k), thereby inhibiting the release of organic matter from the manure. Therefore, this study indicates that the MR for pretreatment of dairy manure could have great potential for significantly enhancing AD of dairy manure. Further studies will include optimization of conditions of mechanical refining (i.e., mechanical intensity, process time), a continuous AD of dairy manure pretreated by the MR, and scale-up with cost evaluation.

Mineral carbonation, which is CO2 fixation through a carbonation reaction using alkaline earth metals, is being investigated as a carbon capture and utilization method to reduce CO2 atmospheric emissions. Concrete sludge is an alkali waste material from the concrete industry and contains abundant calcium components. We investigated the applicability of concrete sludge for mineral carbonation. In this study, gas containing CO2 was bubbled through the model concrete sludge solution and the effects of the solid–liquid ratio, bubbling time, gas flow rate, and the partial pressure of CO2 on the CO2 fixation ratio and fixation rate were investigated. The CO2 fixation ratio decreased with increasing CO2 bubbling time, CO2 flow rate, and CO2 partial pressure. The CO2 fixation rate increased with increasing CO2 flow rate and CO2 partial pressure. The formation of calcite, a form of calcium carbonate, was confirmed.

Thiocyanate (SCN-) is a promising alternative to cyanide as a lixiviant for gold extraction and is 1000 times less toxic than cyanide. In this study, the following leaching parameters were tested to optimize the gold recovery for the first time from an oxide ore using the response surface methodology: initial thiocyanate concentration (10-500 mM), initial Fe3+ concentration (10-500 mM), and pulp density (10-50% w/v). The maximum gold recovery (96%) was achieved with 500 mM thiocyanate, 100 mM Fe3+, and 50% pulp density at 25 °C and pH = 2 for 24 h. A kinetic study on the optimum leaching condition showed that it followed the shrinking core model, in which the rate-controlling mechanism was the diffusion process. These results are discussed in the context of the published literature.

The excellent oil absorption capacity and sustainability advantages of adsorbent-type oil-absorbing products have become the primary method to deal with marine oil spills and organic pollution at this stage, especially aerogel products. However, this type of material also has some problems, such as secondary pollution during nanocellulose preparation. Lignin and hemicellulose were removed from the natural wood, and followed by the action of freeze drying, the wood sponge was prepared. Then, followed by immersing the wood sponge into polyvinyl alcohol solution (PVA) and dipping it in polydimethylsiloxane solution, the target PVA-reinforced wood sponge with better mechanical compressibility and hydrophobic properties was obtained. The new wood sponge showed high mechanical compressibility (reversible compression rate of 40%) and elastic recovery rate (the height retention rate was about 100% after 200 cycles of 30% strain). It also showed excellent hydrophobic and oleophilic properties, and the water contact angle was up to 138°, and the oil absorption capacity was 25 g·g-1. The ability of oil absorption can be recovered by compression, and the high absorption rate was maintained after 50 cycles. The wood sponge has great potential in reusable oil-water separation due to low cost, high efficiency, high performance, biodegradability, environmental friendliness, and other advantages.

To augment sustainable tanning, less chrome input, high functional quality leather processed via no restricted substance in processing, and ease to treat the inevitable protein waste generated are the key challenge, and currently, they have become the active part of leather research. Our work covers the synthesis of a formaldehyde-free chromium-incorporated polymeric tanning agent (FF-CIPTA) and its application in a reformed leather processing route which ensures near zero discharge of chromium containing solid waste. The preliminary characterization of FF-CIPTA reveals that the developed product is stable up to pH 5.2, and the particle size distribution ranges from 955 to 1450 nm with 12% Cr2O3 content. The present work significantly reduces the tanning agent input without compromising the thermal stability (103 °C) of the leather because of its multicrosslinking nature. Since the product exhibits a polymeric character, it provides tanning-cum-filling action which in turn reduces the retanning agent consumption in subsequent processes. Scanning electron microscopic study, porosity analysis, and hand assessment results clearly indicate the significant improvement in organoleptic properties. In addition, the process also enjoys the benefits of zero chromium containing solid waste generation, 71.4% reduction in chromium input, and high chromium transfer efficiency (92%) than the conventional process (36%), and 74.4% reduction in total dissolved solids generation. Furthermore, the water consumption and chemical input are reduced by 51.6 and 17%, respectively. Reduction in wastewater treatment cost and a high economic value of chromium-free leather scraps leads to a cumulative gain of US$ 39.84 per ton of raw material processing. Overall, a potential and practical applicability for cleaner and sustainable tanning is well established.

Phenol and its derivatives are highly toxic chemicals and are widely used in various industrial applications. Therefore, the industrial wastewater streams must be treated to lower the concentration of phenol before discharge. At the same time, food waste has been a major environmental problem globally and the scientific community is eagerly seeking effective management solutions. The objective of this study was to understand the potential of utilizing food waste as a renewable and sustainable resource for the production of activated carbons for the removal of phenol from water streams. The food waste was pyrolyzed and physically activated by steam. The pyrolysis and activation conditions were optimized to obtain activated carbons with high surface area. The activated carbon with the highest surface area, 745 m2 g–1, was derived via activation at 950 °C for 1 h. A detailed characterization of the physicochemical and morphological properties of the activated carbons derived from food waste was performed and a comprehensive adsorption study was conducted to investigate the potential of using the activated carbons for phenol removal from water streams. The effects of pH, contact time, and initial concentration of phenol in water were studied and adsorption models were applied to experimental data to interpret the adsorption process. A remarkable phenol adsorption capacity of 568 mg g–1 was achieved. The results indicated that the pseudo-second-order kinetic model was better over the pseudo-second-order kinetic model to describe the kinetics of adsorption. The intraparticle diffusion model showed multiple regions, suggesting that the intraparticle diffusion was not the sole rate-controlling step of adsorption. The Langmuir isotherm model was the best model out of Freundlich, Temkin, and Dubinin–Radushkevich models to describe the phenol adsorption on activated carbons derived from food waste. This study demonstrated that food waste could be utilized to produce activated carbon and it showed promising capacity on phenol removal.

Renewable carbon sources are a rapidly growing field of research because of the finite supply of fossil carbon. The lignocellulosic biomass walnut shell (WS) is an attractive renewable feedstock because it has a high lignin content (38-44 wt %) and is an agricultural waste stream. Lignin, a major component of lignocellulosic biomass that is currently a waste stream in pulping processes, has unique potential for chemical upgrading because its subunits are aromatic. In the interest of improving the sustainability and reducing the environmental impact of biomass processing, valorization of agricultural waste streams is important. Herein, three lab-scale, batch organosolv procedures are explored in the interest of optimal isolation of protected WS lignin (WSL). One system uses acetic acid, one MeOH, and the final EtOH as the primary solvent. The optimal condition for protected WSL isolation, which resulted in a 64% yield, was methanol and dilute sulfuric acid with formaldehyde to act as a protecting group at 170 °C. Select samples were upgraded by hydrogenolysis over a nickel catalyst. Protected lignin recovered from the optimal condition showed 77% by weight conversion to monomeric phenols, demonstrating that the protected WSL can selectively afford high value products. One key finding from this study was that MeOH is a superior solvent for isolating WSL versus EtOH because the latter exhibited lignin recondensation. The second was that the Ni/C-catalyzed reductive catalytic fractionation (RCF) directly of WS biomass was not selective relative to RCF of isolated WSL; conversion of raw WS to monomers produced significantly more side products.

Oil palm empty fruit bunch (EFB) pulp with the highest cellulose content of 83.42% was obtained from an optimized process of acid pretreatment (0.5% v/v H2SO4), alkaline extraction (15% w/w NaOH), and hydrogen peroxide bleaching (10% w/v H2O2), respectively. The EFB cellulose was carboxymethylated, and the obtained carboxymethyl cellulose (CMC) was readily water-soluble (81.32%). The EFB CMC was blended with glycerol and cast into a composite film. Lignin that precipitated from the EFB black liquor was also incorporated into the film at different concentrations, and its effect on the UV-blocking properties of the film was determined. Interestingly, the EFB CMC film without lignin addition completely blocked UV-B transmittance. The incorporation of lignin at all concentrations significantly enhanced the UV-A blocking and other physical properties of the film, including the surface roughness, thickness, and thermal stability, although the tensile strength and water vapor permeability were not significantly affected. Complete UV-A and UV-B blocking were observed when lignin was added at 0.2% (w/v), and the film also exhibited the highest antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals with an half-maximal inhibitory concentration (IC50) value of 3.87 mg mL–1.

A two-step process of carbonization coupled with steam activation was proposed for wooden activated carbon production from four kinds of biomass waste materials. The TG-FTIR results show that the carbonization process started at around 250 °C and finished at 500 °C for the coconut shell, pinewood, and plywood. The carbonization temperature of corn straw was lower than those of the other three samples, which was attributed to the higher concentration of ash content. FTIR results for the volatile compounds during carbonization show that CH4, CO, CO2, and hydrocarbons are the main detected gaseous species. The CH4 and C m H n yields of pinewood and plywood are higher than those of the coconut shell and corn straw. The carbonization results on the tubular furnace reactor show that furfural and phenol and its derivatives are the main tar compounds in waste carbonization. Carbonization experiments show that a temperature of 500 °C and residence time of 30 min are the optimized parameters for the three biomass wastes. The char yields are 26.4, 25.73, and 30.38% for pinewood, plywood, and coconut shell, respectively. CFD modeling has proven that using 20% of the volatiles could achieve lowest pollution and provide heat for carbonization of biomass waste. The steam activation results show that an activation temperature of 800 °C and activation time of 30 min are suitable for all three biomass samples, which could obtain optimized AC yields and adsorption quality for dioxin.

Used cooking oil (UCO) biodiesel may be one of the most potential alternative fuels in China to lower the dependency on crude oil for transportation. An experimental study has been conducted to assess the interactions between biodiesel produced from UCO in Shanghai and elastomer materials on high-speed marine diesel engines by immersing elastomer materials into conventional fossil diesel, 5, 10, and 20%, of a volumetric blending ratio of UCO biodiesel and pure UCO biodiesel. The test duration is 168 h at different temperatures of 25, 50, and 70 °C. Meanwhile, the effects of the mixing ratio of UCO biodiesel and the immersion temperature on the compatibility of elastomer materials with UCO biodiesel were analyzed. The results revealed that elastomer materials such as nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), fluororubber (FKM), and silicone rubber (SR) exposed to biodiesel blends would reveal worse but acceptable changes than those exposed to petroleum diesel, including the slight increase of mass and volume and decline of tensile strength and hardness. FKM, NBR, and SR represented better compatibility with pure UCO biodiesel than diesel, and EPDM showed worse compatibility with UCO biodiesel as the blend ratio rises. In general, the recommended volumetric mixing ratio of UCO biodiesel should be no larger than 20%. The present study could be helpful for the investigation of UCO biodiesel blends as a potential fuel to satisfy the energy demand.

Organic solvents offer promising methods for the fractionation of Eucalyptus obliqua lignocellulosic biomass. This study investigated the impact of γ-valerolactone (GVL) fractionation on the morphology of cellulose and its internal structure using scanning electron microscopy (SEM), nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopy. The solubilized lignin precipitated on the macrofibril surface as lignin spheres. GVL fractionation significantly increased the crystallinity of the recovered pulps from 0.29 for the sawdust to an average of 0.53 and a maximum of 0.66. The main states of cellulose that were susceptible to hydrolysis during the fractionation were amorphous and surface cellulose, both of which were reduced significantly, while paracrystalline and pure crystalline fractions in the pulp increased. It was concluded that GVL fractionation can produce a crystalline cellulose pulp of high quality suitable for further processing.

The objective of the current research was to fabricate and explore the ability of a renewable resource-based paper strength agent to enhance fiber-fiber bonding and introduce antibacterial properties to recycled fiber paper sheets. The agent corn starch, was modified with diethylenetriamine pentaacetic acid (DTPA), complexed with chitosan, and added to recycled furnishes to provide a plethora of hydrogen bonding sites predicated by acid groups, hydroxyls, and amines. The goal was two-fold: (1) to not only increase interfiber bonding, but (2) afford antibacterial character. The modified corn starch was characterized in previous work by thermal gravimetric analysis, differential scanning calorimeter, and Fourier transform infrared spectroscopy. The recycled pulp slurry was mixed with a ∼1.5% modified starch/chitosan agent before manufacturing a two-dimensional paper substrate that was subjected to mechanical testing. The burst, STFI compressive strength, tensile, and interfiber bonding strength increased 48.8, 49.5, 49.9, and 176%, respectively, while significantly increased gloss was obtained despite slightly diminished tear and roughness. The antibacterial character of these substrates was confirmed by the substrates displaying a 97% bacteria kill rate.

The coating structure is directly related to quality of coated paper, especially printability. Its structure mainly consists of pigment, binder, and additives. Binder has a significant influence on the coating structure because it is involved in the structure forming process and takes a key role in maintaining the structure. In this study, styrene acrylate (S/A) latex with hydroxyethyl methacrylate (HEMA) as a comonomer was used as a binder, and the influence of HEMA contents on latex swelling and coating structure was investigated. The S/A latex particle swelled more with an increasing HEMA content, which significantly influenced coating color and coating layer characteristics. The viscosity of coating color became thick, and the dewatering of coating color was suppressed. The HEMA monomer that swelled latex particle allowed the coating layer to consolidate rapidly, which made the coating layer more porous and more uniform.

Oily sludge is a hazardous waste. If not handled properly, it can not only pollute the environment but also endanger human health. This study is the first to use a response surface method to optimize the main parameters of rhamnolipid-based recovery of oil from oily sludge. Using rhamnolipids as the cleaning agent and the oil recovery fraction as the evaluation index, the factors affecting the cleaning efficiency of oily sludge were optimized. The aforementioned sludge was obtained from the Tarim Oilfield. A single-factor experiment was conducted to determine the optimal range of the dosage, liquid-solid ratio, pH value, and time. The Box-Behnken response surface method was used to investigate the influence of each variable on the residual oil fraction of the oily sludge, and the dosage, pH value, and time were found to have a significant impact. The model optimization results show that the best process conditions for rhamnolipid-based recovery of oil are as follows: rhamnolipid dosage = 167.785 mg/L; liquid-solid ratio = 4.589:1; pH = 9.618; time = 1.627 h. Under optimal conditions, the model-predicted oil recovery fraction and the actual oil recovery fraction were 85.15 and 82.56%, respectively; the relative error between the predicted and the actual values was 2.59%. These results indicate that the model results are reliable. The solid residue after the cleaning was also analyzed to gain an in-depth understanding of the cleaning process. This study determined the feasibility of a rhamnolipid-based solution for the treatment of oily sludge and oil-contaminated soil.