Improving Electrochemical Performance of Cellulose Fiber-based Supercapacitor Electrode Using Polypyrrole-wrapped Iron Oxyhydroxide

Polypyrrole (PPy)@cellulose fiber-based composites have been widely investigated as electrode materials for use in flexible supercapacitors. However, they cannot readily provide high specific capacitance and cyclic stability owing to their inherent drawbacks, such as high resistance, Weber impedance, and volume expansion or collapse during charging/discharging. In this study, iron oxyhydroxide (FeOOH) is incorporated in the abovementioned composite to decrease the equivalent series resistance, charge transfer resistance, and Weber impedance, thereby enhancing electron transfer and ion diffusion, which results in superior electrochemical performance. The PPy-wrapped FeOOH@cellulose fiber-based composite electrode with the molar ratio of FeSO₄ to NaBH₄ of 1∶1 exhibits a high specific capacitance of 513.8 F/g at a current density of 0.2 A/g, as well as an excellent capacitance retention of 89.4% after 1000 cycles.     

Effects of ZnCl2/H2O/C2H5OH Treatment on the Filter Paper Performance

Bleached softwood kraft pulp (BSKP) fibers were pretreated in a 5 mol/L NaOH aqueous solution at 35℃ for 90 min. The ZnCl₂/H₂O/C₂H₅OH was used to treat the pretreated BSKP fibers, filter papers were then prepared. In the course of processing, the effects of various molar ratios of ZnCl₂/H₂O/C₂H₅OH on the filter paper performance were evaluated. SEM-EDX was conducted to analyze the physical configuration of the filter papers. Moreover, FT-IR and XPS were performed to further characterize the BSKP, the pretreated BSKP and the filter paper fibers. The results indicated that the fibers treated by ZnCl₂/H₂O/C₂H₅OH were swollen and exhibited slight fibrillation, leading to a looser fiber structure and therefore, enhanced filter paper performance. Air permeability increased from 161.7 L/(m²·s) to 1450.4 L/(m²·s) for the filter papers when the molar ratio of ZnCl₂/H₂O/C₂H₅OH was 1:14:1. The optimum molar ratio of ZnCl₂/H₂O/C₂H₅OH was found to be 1:14:1, and no significant effect of ZnCl₂/H₂O/C₂H₅OH on fibers’ functional groups was detected. These results showed that filtration performance of filter papers was improved when treated with the ZnCl₂/H₂O/C₂H₅OH solution.     

Mg（OH）2粒径对辐射松氧脱木素的影响

为进一步探讨镁盐作为纤维素保护剂的作用机制,研究了纸浆氧脱木素过程中添加不同粒径（20、50、100、200、500 nm）的Mg（OH）₂对添加多种过渡金属离子（Cu²⁺、Mn²⁺和Fe³⁺）的辐射松硫酸盐浆氧脱木素的影响,通过测定氧脱木素后纸浆卡伯值和黏度,分析不同粒径Mg（OH）₂对纤维素的保护效果。研究结果表明,在纸浆氧脱木素过程中,不同粒径的Mg（OH）₂对纸浆卡伯值、木素脱除率没有显著影响;但小粒径的Mg（OH）₂对纸浆黏度的保护能力要优于大粒径的Mg（OH）₂。氧脱木素中添加Mg（OH）₂粒径越小,纸浆黏度降低越少,手抄片物理强度越大。     

Preparation of High-precision Electrospun Nanoair Filter Paper for Air Purification

Electrospinning technology has become a research hotspot because of its advantages, such as simple operation, low cost, large specific surface area, high porosity, and good fiber continuity. Here, a new type of composite nanoair filter paper was prepared using electrospinning technology. To improve the practicability of air filter base paper, phenolic resin was used as a curing agent to improve the strength. The results show that the electrospun nanoair filter paper with air filter paper as the receiving substrate and polyvinyl alcohol (PVA) solution as the spinning solution excellently performed in all aspects. The influence of the thickness (spinning time) of the PVA nanofiber membrane on the micromorphology, physical properties, and filtration performance of the electrospun nanoair filter paper was analyzed. According to the ISO 5011-2014 standard, the initial resistance, filtration efficiency, mean pore size, and dust capacity of the electrospun nanoair filter paper were 77.3 Pa, 99.9941%, 3.50 μm, and 146 g/m², respectively, when the spinning time was 15 min.     

Preparation of Soy Peptides by Liquid Fermentation

Many kinds of microorganism can produce a mount of protease which subsequently hydrolysis the protein of the medium into peptides when they grow in protein containing liquid medium.In the present investigation,the conditions of preparing soybean peptides by liquid fermentation were studied,following results were obtained:(1)SPI is a nice nitrogen source and meanwhile an inducible factor of protease production;its concentration can be as high as 3%-4%.(2)Sucrose is the best carbon source;its concentration is 1%-4%.(3)Under the conditions of 28℃,initial pH6.0,inoculum size 4%,cell age 36hr and fermentation time 24hr-30hr,we can obtain soybean peptides or fermentation liquor with good flavor,its DH reaches 25%-30% and the yield rate can be as high as 75%.(4)Mass spectrograph indicate the MW of the fermentation liquid or the soybean peptides mainly distribute at about 4000Dal,these imply a promising prospect of industrial application of submerged fermentation in producing soybean peptides.     

Formation and Collapse of Cellulose Nanocrystals and Hydrophobic Association-induced Dual Cross-linked Nanocomposite Hydrogels: A Rheological Study

The rheological characteristics of a physical gelation system, in which cellulose nanocrystals (CNCs) induced the entanglement of poly(acrylic acid) (PAA) chains and partial hydrophobic association of octylphenol polyoxyethylene acrylate (OP-10-AC) branches in a micellar solution of sodium dodecyl sulfate (SDS), were investigated. The gelation time of the physical gels decreased as the CNC content and number of hydrophobic branch units increased. At the gel point, the storage modulus (G'') and loss modulus (G") followed the same frequency dependence (G'' ≈ G" ≈ ωⁿ), where the hydrophobic moieties attached to the side chains had a significant impact on the values of viscoelastic exponent (n). Beyond the gel point, the initial polymer solution was transformed to a solid-like gel, and the strength of the gel network was governed by associations between both the CNCs and hydrophobic groups. The evolution of the viscoelasticity during the gel-sol transition was monitored, demonstrating that due to a reversible arrangement of the hydrophobic units, a large proportion of physical cross-links dissociated under a thermal trigger and were reversibly reformed when the solution was cooled, while no such partial recovery was observed in the case of the single CNC-induced network systems (with no hydrophobic branches).     

麦胚蛋白酶解产物对过氧化氢诱导PC12细胞损伤的抗氧化作用

Wheat germ protein isolate hydrolysates (WGPIH) were prepared under different enzymolysis time and the antioxidant effects of different WGPIH against the H₂O₂-induced oxidative stress in PC12 cells were compared through MTT method combined with their antioxidant activities in vitro, and the changes of the PC12 cells surface microstructures were observed by SEM. The results showed that the hydrolysate WGPIH5 produced by hydrolyze for 240 min possessed the highest antioxidant activity, its IC₅₀value for ferrous iron-chelating activity was（0.37±0.05）mg/mL;TEAC value （Trolox） reached（0.81±0.01）mmol/L with 5 mg/mL WGPIH5; the autooxidation of linoleic acid was significantly inhibited by WGPIH5;WGPIH5 was able to attenuate H₂O_{2相似文献}   

Nano-Cu2O-loaded Paper: Green Preparation and High Visible Light Photocatalytic Performance for Formaldehyde Removal

The removal of formaldehyde (HCHO) from indoor air is of great importance to reduce health risks and improve indoor air quality. In this study, nano-Cu₂O-loaded paper with superior photocatalytic activity under visible light for the removal of HCHO was fabricated through a green, simple, and fast in situ synthesis method. The optimum preparation conditions for nano-Cu₂O-loaded paper were as follows: 2 g (oven-dry basis) cellulose fibers, CuSO₄ dosage 8 g, NaOH dosage 1.6 g, temperature 80℃, 60 min for Cu²⁺ absorption, and 60 min for reaction. Under the optimum conditions, the Cu₂O deposition ratio approached 30% and the nano-Cu₂O-loaded paper exhibited a catalytic efficiency of approximately 97% for HCHO removal. The photocatalytic capacity of nano-Cu₂O-loaded paper for HCHO removal had a positive correlation with the deposition ratio of nano Cu₂O particles. Excellent antibacterial property of nano-Cu₂O-loaded paper against Staphylococcus aureus and Escherichia coli was also confirmed. Moreover, nano-Cu₂O-loaded paper was proven to be hydrophobic.     

Preparation and Characterization of Cellulose Nanofibril-Waterborne Polyurethane Composite Films

To improve the performance of polyurethane films, small amounts of cellulose nanofibrils(CNF) were physically blended with a waterborne polyurethane(WPU) emulsion, and then CNF/WPU composite films were prepared by cast-coating and drying. The particle size of the emulsions and the chemical structure, micromorphology, thermal stability, mechanical properties, and water resistance of the composite films were characterized using a Malvern laser particle size analyzer, Fourier transform infrared spe...     

Parameters Influencing Power Generation in Eco-friendly Microbial Fuel Cells

Pulp and papermaking industries generate high volumes of carbohydrate-rich effluents. Microbial fuel cell (MFC) technology is based on organic materials’ consumption?and efficient power production. Using a classical two-chamber lab-scale MFC design with an external resistance of 2000 W, we investigated the effects of anode chamber biofilm adaptation (ACBA) and cathode chamber redox solutions (CCRS) on the operation efficiency of MFC when treating wastewater. In ACBA studies, biofilm growth activation showed an increase in the power density to 20.48, 35.18, and 36.98 mW/m² when the acetate feeding concentrations were 3, 6, and 12 g/L, respectively. Improvement by biofilm adhesion on granular activated carbon (GAC) was examined by scanning electron microscopy (SEM). The obtained power density increased to 25.47, 33.42, and 40.39 mW/m² when the GAC particles concentrations were 0, 50, and 100 g/L, respectively. The generated power densities were 51.26 and 40.39 mW/m² as well as the obtained voltages were 0.41 and 0.72 V when the electrode area increased from 16 to 64 cm²², current density of 0.094 A/m², and voltage of 1.20 V with a successful organic removal efficiency of 86.0% after 264 h of operation.     

Effect of Thermal Treatment on the Properties of TEMPO Oxidized Cellulose Film for the Flexible Substrate of Solar Cell

The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized cellulose film (TOCF) has been attempted to be used as a substrate in electronic and optoelectronic devices, but the changes in the TOCF properties before and after annealing treatment have usually been neglected during device fabrication. In this study, TOCF was treated in different atmospheres (air, vacuum, and N₂) and at different temperatures, and the properties were investigated. The results indicate that the optical properties are slightly affected by atmosphere and temperature; only slight transmittance loss and haze increase have been observed when TOCF is exposed to an air atmosphere at temperatures of above 120℃. In contrast to the slight effects on the optical properties, cellulose degradation and a loss of film strength have been observed regardless of the atmosphere used when placed at temperatures of above 100℃. Specifically, TOCF was exposed to air, followed by N₂ and vacuum atmospheres. Additional Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) results showed that increasing the temperature had no significant effect on the structure of TOCF. Therefore, the annealing temperature should be controlled at a temperature of lower than 100℃ and a vacuum atmosphere is preferred.     

Synthesis of Fe3+-doped Aminated Lignin as A Peroxidase Mimic for Colorimetric Detection of H2O2 and Glucose

Peroxidase plays an important role in living systems; however, its storage difficulty and easy inactivation have limited its applications in complex environments. To address these problems, herein, we proposed a method to synthesize peroxidase mimics by amination, carbonization, and Fe³⁺-doping of industrial alkali lignin. The Fe³⁺-doped lignin-based peroxidase mimic (Fe-LPM), with active centers of coordination between Fe³⁺ and N atoms, showed higher tolerance to pH value and temperature than natural peroxidase. Using Fe-LPM, 10-100 mmol/L of H₂O₂ and glucose could be colorimetrically detected with the lowest detection limits of 80 μmol/L and 1.5 mmol/L and visual detection limits of 1.0 mmol/L and 10 mmol/L, respectively. The Fe-LPM maintained peroxidase-like activity after 10 cycles and could even be used for H₂O₂ detection in practical samples. This work not only provides a new approach to synthesize peroxidase mimics using biomass materials but also promotes the high-value utilization of lignin.     

Etherification of Alkali-pretreated Sugarcane Bagasse Cellulose in Tetrahydrofuran

Sugarcane bagasse (SCB) is an important by-product in the sugar industry. It is a source of cellulose fibers or cellulose for paper mills and textiles factories. In this study, SCB was ethyl etherified in tetrahydrofuran (THF) after alkali pretreatment. The alkali concentration for the pre-treatment, the ratio of ethyl bromide (EtBr) to dried SCB in the reaction, reaction time, and temperature were investigated for the etherification of SCB. The ethoxyl content and characterization of the product were determined using headspace gas chromatography (HS-GC), Fourier Transform Infrared (FT-IR) and ¹³C-NMR spectroscopy, respectively. It was found that SCB was well-etherified with EtBr in alkali-THF. Upon ethylation of SCB, the ethoxyl content of the product was high when the alkali concentration and the ratio of EtBr to dried SCB were controlled from 50% to 75% and 4:1 (V/w) to 6:1 (V/w), respectively. The reaction occurred optimally when the temperature was controlled below 110℃; above this temperature, the degree of etherification decreased. The thermal stability of ethylated SCB was higher than that of SCB but slightly lower than that of commercial ethyl cellulose. Ethylated SCB has the potential to form composites with many materials because it is soluble in a wide variety of solvents.     

Preparation and characteristics of bombyx mori sericin / tussah silk fibroin / gelatin-based blended antibacterial films北大核心CSCD

A large number of wound dressings are currently used in the treatment of burns chronic ulcers etc. An ideal wound dressing should prevent dehydration of the wound and retain a favorable moist environment at the wound interface. It should have good antibacterial properties and be easily removed without trauma too. Wound dressings are generally made of readily available bio-materials that require minimal processing possess nontoxic non-allergenic and antimicrobial properties as well as promote wound healing. Clinically collagen chitin chitosan etc. are usually used as materials for producing wound dressings as these materials are capable of accelerating the healing processes at molecular cellular and individual levels. Tussah silk fibroin bombyx mori sericin and gelatin non-toxic and extensive have good bio-compatibility degradability and film-forming properties which are conducive to cell adhesion. In order to prepare safe biofilms with excellent antibacterial properties we prepared a kind of bombyx mori sericin / tussah silk fibroin / gelatin BS-TSF-GEL blended film by using tussah silk fibroin bombyx mori sericin and gelatin as bio-based materials and polyethylene glycol 200 as the cross-linking agent. Firstly we designed the single factor experiment and orthogonal experiment to optimize the preparation process of the BS-TF-GEL blended film. On this basis the blended film was modified with ethanol of different concentrations to improve its strength and crystallinity. The structure and properties of the blended film were characterized by measuring the dissolution loss rate tensile properties microscopic morphology and crystal structure. Finally antimicrobial peptides were loaded by adsorption to obtain the BS-TSF-GEL antimicrobial film. The results showed that the ratio of the optimum formula for the (BS-TSF-GEL) blended film required a mixture of bombyx mori sericin (4. 50 μg / mL) and tussah silk fibroin (27. 5 mg / mL) with a volume ratio of 2:1 polyethylene glycol 200 and gelatin solution (360 mg / mL) which accounted for 35% 40% and 25% respectively of the total system. The dissolution loss rate of the BS-TSF-GEL blended film was 34. 62% the elongation at break was 34. 15% and the breaking strength was 578. 8 kPa after being treated with anhydrous ethanol. FTIR and X-ray diffraction results showed that Silk Ⅱ dominated the BS-TSF-GEL blended film while Silk Ⅰ was in a small amount. The BS-TSF-GEL blended film was pale yellow and porous on the surface which was the ideal material for loading antimicrobial peptides. The BS-TSF-GEL blended film loaded with antimicrobial peptides had a good inhibitory effect on both Escherichia coli and Staphylococcus aureus. It is expected to be used in the field of disposable biomedical materials such as wound dressings. In this study three natural materials with unique advantages were selected as substrates for biofilms and polyethylene glycol with high bio-safety was used as the cross-linking agent to enhance the application value of the blended film by loading antimicrobial peptides. The results broaden the application field of silkworm silk and provide a new way for the development and exploitation of silk fibroin in biological dressings and other medical bio-materials. Bombyx mori sericin tussah silk fibroin and gelatin have been widely used in biological tissue engineering as natural biological materials. In this study three natural materials were used as the biofilm substrate to successfully prepare excellent-performance BS-TSF-GEL blend film using polyethylene glycol cross-linking and ethanol post-treatment techniques. Moreover specific properties can be conferred by replacing different loading substances such as antimicrobial biofilm carrying antimicrobial peptides and biofilm sustained release carrier loading drugs. In addition 3D printing electrostatic spinning and other technologies can also be used to shape the BS-TSF-GEL into different shapes to meet the application requirements under different conditions. In conclusion the research results explore a new way for the application of silk protein. © 2022 Authors. All rights reserved.     

淀粉-脂肪酸改性高岭土的制备及其在包装纸上的应用

To improve the bondability between clay filler and lignocellulosic fiber,Kaolin clay particles were modified using a starch-fatty acid complex method.The coating efficiency of starch on clay particle surfaces was investigated by measuring the dissolved starch in the supernatant.The experimental results indicated that more than 98%of the applied starch was precipitated onto the surface of the filler,and the resulting starch-fatty acid-clay composites had relatively good resistance against moderate shear force.The morphology,particle size,andζpotential of the starch modified filler were also determined with scanning electron microscopy,Malvern particle size analyzer,and Malvern Zetasizer,respectively.An aqueous slurry of linerboard pulp containing 5～15wt%modified fillers was used for handsheet preparation,and the effects of the addition of modified filler on the paper properties were studied.At a dosage of 10%of the modified filler(based on filler), the retention of the filler was higher than 75%.The strength properties of paper with starch modified fillers were improved by approximately 15%when compared against those of paper with unmodified fillers.     

Triethylamine-catalyzed Isomerization of Glucose to Fructose under Low Temperature Conditions in Aqueous Phase

Isomerization of glucose derived from lignocellulosic biomass is an important step in biorefinery. Fructose isomerized from glucose, is used as a highly attractive sweetener in the food and beverages industries. However, the prevalence of side reactions at high glucose concentrations is a serious issue, leading to a significant reduction in the fructose yield, especially in the aqueous phase. In this study, an efficient method for the conversion of highly concentrated glucose into fructose under low temperature conditions using triethylamine as the catalyst was developed. It was demonstrated that high fructose yield could be maintained at high glucose concentration. At 60℃, fructose yield of 38.7% and fructose selectivity of 80.6% were achieved in 1 mol/L (approximately 17 wt% ) glucose. When glucose concentration was increased to 2 mol/L (approximately 31 wt%), the fructose yield and selectivity were maintained at 34.7% and 77.4%, respectively. ¹³C nuclear magnetic resonance (NMR) spectrometer was used to examine the glucose isomerization reaction. Compared to the NaOH catalytic system, triethylamine acted as a buffer to provide a stable alkaline environment for the catalytic system, further maintaining a high level of catalytic efficiency for the isomerization of glucose to fructose.     

8.Standards for Grade(2)

The original set of the physical standards currently in effect is sealed and depositedin a vault at the USDA in Memphis or Washington,D.C.Copies of these,known as pra-ctical forms,are prepared and sold by USDA.In addition,guide boxes containing sixsamples are prepared and sold.The utmost care is taken to keep the range of color,leaf,and preparation in all copies of each standard,as nearly the same as possible.The color of cotton deepens with age—more in the high grades than in the low gradesand more in Tinged and Spotted grades than in the Gray grades.The color of the cottonin the standards stored or used under different conditions may differ considerably as time     

Low Temperature Hydrothermal Synthesis of Ultra-light and Superelastic Graphene Oxide/Cellulose Aerogels for Absorption of Organic Liquids

Two-dimensional(2 D) graphene oxide(GO) nanosheets and 1 D2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO)-oxidized cellulose nanofibers(TOCN) were assembled into GO/TOCN aerogels via a low temperature hydrothermal and freeze-drying process. The as-prepared GO/TOCN aerogels exhibited interconnected 3 D network microstructures, a low density of 6.8 mg/cm~3, a high porosity up to 99.2% and excellent mechanical flexibility.The high porosity in conjunction with their hydrophobicity(contact angle of 121.5°), allowed the aerogels to absorb different organic liquids with absorption capacities up to 240 times of their own weight, depending on the density of the liquids. These results indicated that the aerogels were excellent candidates as sorbent materials for the clean-up of organic liquids. After five absorption-desorption cycles, the absorption capacity of the TOCN carbon aerogels could be regenerated up to 97% of the initial absorption capability,which demonstrated their excellent recyclability.     

Synthesis of Humin-based Carbon Quantum Dots and Luminescent Properties

The unique properties of carbon quantum dots(CQDs) make them promising materials in many fields. Herein, we present a facile method for the preparation of photo-luminescent CQDs using humins as the carbon precursor for the purpose of providing a high value-added solution for this "biomass conversion process waste". The structure of the CQDs was analyzed, and the effects of reaction temperature and time on the CQDs' fluorescence were investigated. The results showed that humins were effectively carbonized during the reaction. The fluorescence intensity of humin-based CQDs initially increased with reaction temperature and time, and subsequently decreased beyond 200℃ and 4 h. Polyaromatic structures and hydrophilic groups such as O—H, C—O, —COOH and C==O groups exist in the CQDs. The huminbased CQDs have the dimension of 3～7 nm with an average size of about 5.5 nm. The highest emission intensity of blue/cyan fluorescence light at 440 nm is achieved on the excitation with UV light at the wavelength of 330 nm.     

Carboxyethylated Microfibrillated Cellulose Fibers Prepared from Different Raw Materials

Carboxyethylation pretreatment was used to prepare microfibrillated cellulose(MFC)in this study.In order to evaluate the adaptability of this pretreatment method,carboxyethylated MFC was prepared from six different cellulosic materials.The carboxyl content,degree of polymerization,water retention value,charge density,chemical structure,size distribution,and micromorphology of the materials before and after pretreatment and grinding were studied and compared.The viscosity,ultraviolet(UV)transmittance,and thermal stability of the MFC samples at a certain concentration were determined.The results showed that the carboxyl content,water retention value,charge density,degree of polymerization,size distribution,and micromorphology of the pretreated and ground samples varied with those of the raw materials.The initial viscosity varied based on the type of raw material used.The MFC suspension prepared from cotton linter pulp had the highest UV transmittance,while the MFC prepared from bleached softwood kraft pulp had the highest viscosity at a low shear rate.After thermal degradation,the amount of residual char from the MFC prepared with the thermo-mechanical pulp was slightly higher than that of the other MFCs.This study demonstrates that carboxyethylation is an effective pretreatment method for different cellulosic materials.