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As the rapid increasing demand for electrical energy in the world, the research on electrical energy storage becomes urgent and crucial, especially for these ones with the features of cost-effectiveness, high safety and outstanding performance. Aqueous zinc ion batteries (AZIBs) are regarded as environmentally friendly, safe, reliable, and promising devices for electrochemical energy storage systems. However, a variety of challenges such as zinc dendrite formation, corrosion and hydrogen evolution must be addressed for the practical, widespread application of AZIBs. Recently, there has been notable interest in utilizing renewable, biodegradable, and cost-effective lignocellulosic materials to address these challenges, as they have the potential to significantly improve the electrochemical performance of AZIBs. However, there is a lack of comprehensive and systematic summary, as well as a gap in theoretical analysis, on the role of lignocellulosic materials in improving AZIBs performance. The present review covers the development, concept, advantages, and challenges of AZIBs. The most recent advancements and progress on the lignocellulosic materials (including cellulose, lignin, and hemicelluloses) as electrodes, electrolytes and separators for AZIBs applications are summarized. A perspective on existing challenges, potential solutions, and promising prospects of lignocellulosic materials is outlined, aiming to provide the research community with essential technical insights that could drive the commercialization of green and sustainable lignocellulosic materials in high-performance AZIBs. [Display omitted] • The advantages and current challenges of AZIBs have been systematically discussed. • The recent progress of developing lignocellulosic materials for AZIBs has been reviewed. • The strategies for improving the performance of AZIBs via incorporating lignocellulosic materials have been summarized. • The challenges and perspectives in developing lignocellulosic materials for advanced AZIBs have been addressed. [ABSTRACT FROM AUTHOR]

Combining chemi-mechanical pulping with autohydrolysis pretreatment is an efficient and value-added utilization approach for lignocellulosic biomass in paper industry. To further promote the utilization of autohydrolyzed biomass in chemi-mechanical pulping, the color evolution of poplar wood chips in autohydrolysis pretreatment and its chromogenic mechanism were investigated by using CIELab color system, FT-IR, NMR and GPC. The results showed that the total color difference ΔE* increased obviously, which were remarkable as the combined hydrolysis factor (CHF) increased. The lignin content led to a more significant influence on the color of poplar wood chips than the extractives. The autohydrolysis pretreatment with a higher CHF accelerated the degradation and subsequent condensation of lignin, resulting in the formation of chromophoric groups, such as Hibbert ketone, quinones and quinone methides. It is of great significance for biomass refinery and paper industry to reveal the color evolution of poplar wood chips caused by autohydrolysis pretreatment from the point of view of chemical components' structure. Unlabelled Image • The color evolution of autohydrolyzed wood chips was investigated. • Chromogenic mechanism of the wood chips in autohydrolysis process was revealed. • The color of poplar wood chips became deep after autohydrolysis with a higher CHF. • Lignin has a greater impact on the coloring of poplar wood chips than extractives. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Poplar sapwood chips were autohydrolyzed followed by an alkali impregnation. • Other chemical components had less impact on alkali impregnation than surface lignin. • Surface lignin had no effect on alkali impregnation compared to the volume porosity. • Autohydrolysis can facilitate chemi-mechanical pulping. Abstract Chemi-mechanical pulping, a typical high-yield pulping method, combined with autohydrolysis pretreatment prior to pulping is an efficient and value-added utilization method for biomass in pulp and paper industry. This study investigated the surface lignin changes of poplar sapwood chips in autohydrolysis pretreatment and their effect on the subsequent alkali impregnation for chemi-mechanical pulping. The results showed that the surface lignin content went up with the increase of autohydrolysis intensity, and that the existence of the surface lignin had nearly no impact on the subsequent alkali impregnation in making chemi-mechanical pulps (CMPs) compared to the volume porosity, which was validated by using the stepwise regression analysis. It can be further concluded that autohydrolysis can facilitate the subsequent alkali impregnation of the autohydrolyzed sapwood chips in making CMP, which would be of significance for the combination of biomass refinery and pulp and paper industry. [ABSTRACT FROM AUTHOR]

This work investigated the changes in the physical structure of autohydrolyzed poplar sapwood chips and the effect on the subsequent alkali liquor diffusion properties for chemi-mechanical pulping (CMP). An alkali impregnation process was conducted by using the autohydrolyzed poplar sapwood with different levels of autohydrolysis intensity. The results showed that the volume porosity, water constraint capacity, and saturated water absorption of the autohydrolyzed poplar sapwood chips increased. Also, the effective capillary cross-sectional area (ECCSA) in the radial direction and the diffusion coefficients of NaOH solution in both the radial and axial directions all increased. Autohydrolysis pretreatment enhanced the alkali liquor diffusion properties in poplar sapwood chips, and the diffusion coefficient was increased more greatly in the radial direction than that in the axial direction. [ABSTRACT FROM AUTHOR]

Bamboo chips were efficiently fractionated using an integrated process of autohydrolysis and formic acid to induce rapid delignification. Autohydrolysis pretreatment facilitated oligosaccharide production, while the subsequent rapid-delignification using formic acid at a low liquid/solid ratio with a relatively short reaction time allowed obtaining cellulose fibers and lignin. The major inter-unit linkages of side-chain in lignin were cleaved during the combined fractionation process. The lignin fraction exhibited higher purity, more phenolic OH groups, less condensed phenolic OH groups, and higher syringyl/guaiacyl ratio (S/G) as compared to MWL and formic acid lignin from the direct formic acid delignification. These results indicate that the combined fractionation process presents a promising approach to the commercial utilization in the biorefinery industry. [ABSTRACT FROM AUTHOR]

Bamboo was fractionated using formic acid based on a one-step organosolv process under high pressure (at 145 °C for 45 min, 0.3 MPa) and at atmospheric pressure (at 101 °C for 120 min), respectively. High-pressure formic acid lignin, atmospheric formic acid lignin and milled wood lignin of bamboo were subjected to comprehensive structural characterization using gel permeation chromatography (GPC), Fourier transform infrared (FTIR) and solution-state NMR techniques ( 1 H, 13 C, 2D-HSQC, and 31 P-NMR spectroscopies). The results indicated that the formic acid fractionation under high pressure presents a quick and efficient delignification method by enhancing the cleavage of interunitary bonds in lignin (β-O-4′, β-β and β-5′), and dissolved lignin also occurred condensation reaction. As compared to atmospheric formic acid lignin, high-pressure formic acid lignin obtained showed higher purity and yield, and had relatively higher contents of phenolic and carboxylic groups. [ABSTRACT FROM AUTHOR]

This work is aimed at investigating the influence of changes in the content of hemicelluloses of the autohydrolyzed poplar sapwood on the subsequent alkali impregnation for chemi-mechanical pulping (CMP). An alkali impregnation process was conducted using the autohydrolyzed poplar sapwood with different content of hemicelluloses as raw materials. The results showed that both the amount of NaOH consumption and swelling degree of poplar sapwood increased with the removal of hemicelluloses, thus enhancing the alkali impregnation effectiveness. The hemicelluloses removal can also shorten the alkali impregnation time for the autohydrolyzed poplar sapwood to achieve the similar impregnation effectiveness of unautohydrolyzed poplar sapwood. All of these can be attributed to the fact that the hemicelluloses removal would result in the exposure of more free hydroxyl groups on the cellulose and an increase in the porosity of the fiber cell walls. [ABSTRACT FROM AUTHOR]

Xylan is a part of hemicelluloses of woody materials and can be converted to value-added products such as flocculants for the textile industry. To assess the production of flocculants from hemicelluloses of woody materials, xylan was selected as a model and rendered cationic via copolymerization. In this study, the copolymerization reaction of xylan and [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC) was optimized. The optimum parameters were 3 mol/mol METAC/xylose, 3 h reaction time, 80 °C reaction temperature, pH 7 and 25 g/L xylan concentration. The copolymer was characterized by a charge density analyzer, viscometer, gel permeation chromatography (GPC), light scattering instrument, Fourier transform infrared spectroscopy (FTIR) and an elemental analyzer. The application of the cationic xylan copolymer as a flocculant to decolorize the simulated reactive orange 16 azo-dye wastewater was evaluated. The results confirmed that, by having 160 mg/L xylan–METAC concentration in the dye solution with the concentration of 100 mg/L, 97.8% of dye could be removed. [ABSTRACT FROM AUTHOR]

This study investigated the autohydrolysis pre-treatment prior to chemi-thermomechanical pulping (CTMP) process including the effects of autohydrolysis pretreatment with a lower severity on characteristics of the autohydrolysis liquor and hydrolyzed chips. The intensity of autohydrolysis, characterized by the severity factor, increased from 1.76 to 3.54, the hydrolyzed chips yield decreased from 99.0% to 86.7% and the xylose extraction yield increased from 0.8% to 44.0%. The content of holocellulose, pentosan and acid soluble lignin remained in the hydrolyzed chips decreased dramatically with increasing the treatment severity. After the autohydrolysis pretreatment, the resultant poplar chemi-thermomechanical pulp with a severity factor of 2.37 could obtain a 15.3 N m/g tensile index, 58.6% ISO brightness and a 2.39 cm 3 /g bulk. [ABSTRACT FROM AUTHOR]

Abstract: Bleached thermomechanical pulp (TMP) has been applied in the production of newsprint and supercalendered (SC) paper or other paper products. Recent studies on the alkaline peroxide bleaching with magnesium-based alkalis indicated that the bulk and optical properties can be improved, and effluent load can be reduced. In this work, MgO was partially used in alkaline peroxide bleaching process of pine (Pinus massoniana) TMP to investigate the effect of MgO substitution for NaOH on the pulp properties and effluent characteristics. The present research showed that partial substitution of MgO for NaOH could decrease the dissolution of chemical components in pulp fibers, thus, improving the pulp yield and decreasing the effluent load. When the substitution percentage of MgO for NaOH increased from 0% to 50% at 3.5% alkali charge, the bulk of the bleached pine TMP increased from 3.45cm3/g to 3.69cm3/g, while the opacity was improved from 84.7% to 89.1%, the cationic demand and CODCr of the effluent decreased by 31% and 22%, respectively. However, the MgO substitution had decreased the brightness and tensile index of the bleached TMP. [Copyright &y& Elsevier]

Abstract: Wheat straw has been used as a pulping resource in China for many years. Wheat straw pulp (WSP) was widely used to substitute high quality chemical pulps such as those made from wood in producing writing and printing paper to reduce production cost of the resultant paper products and to improve paper smoothness without sacrificing paper strength. In this study, the process of co-refining of WSP and bleached hardwood kraft pulp (BHKP) was compared with the traditional separate refining and then blending these two pulps. The differences in refining energy consumption, the resultant pulp morphological and drainage properties, as well as the mechanical properties of the paper handsheets made of the resultant pulps were examined to explore the potential advantages of the co-refining process. The results show that the co-refining process has the potential to reduce refining energy consumption by at least 30% without affecting handsheet tensile and tear strength at a slightly lower re-wet tensile strength. [Copyright &y& Elsevier]

Abstract: A kind of antimicrobial fibers, a composite of Chitosan-Dialdehyde Cellulose (C-DAC) fibers, was prepared by using commercially elemental chlorine-free (ECF) bleached kraft softwood cellulose fibers oxidized by periodate and then further grafted by chitosan with different molecular weights. The characteristics of the C-DAC fibers and physical properties as well as antimicrobial activities of the handsheet made of C-DAC fibers were measured. The results show that the dry and rewet tensile indices, antimicrobial activity against Staphylococcus aureus and Escherichia coli, can be improved significantly as the molecular weight of grafted chitosan on the dialdehyde cellulose fibers decreases. [Copyright &y& Elsevier]

Dilute acid pre-extraction enhanced the mechanically refined poplar pulp substrates’ enzymatic hydrolysis efficiency obviously. The results showed that the surface lignin distribution was changed significantly in residual wood chips and pulp substrates, and the surface lignin distribution showed important impact on the following enzymatic hydrolysis. Acid pre-extraction can lead to a redistribution of lignin in fiber cell walls, i.e., the lignin was degraded and migrated to fiber surface in the form of re-deposited lignin and pseudo-lignin. However, higher pre-extraction intensity was not desired due to the formation of redeposited lignin and pseudo-lignin. This study will help to reach a deeper understanding on the lignin distribution in the view of molecular and ultrastructure, and promote the development of a cost-efficient pretreatment strategy for biomass processing. [ABSTRACT FROM AUTHOR]

Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation. [ABSTRACT FROM AUTHOR]

The hardwood bleached kraft pulp (HBKP) fibers were pretreated by PFI mill to obtain the substrates, the effects of fibrillation on HBKP fibers’ enzymatic hydrolysis was studied. The results showed that the enzymatic hydrolysis efficiency was enhanced obviously by mechanical refining. The mechanical refining alterated the fibers’ characteristics such as fibrillation degree, specific surface area, swelling ability, crystallinity, fiber length and fines content. All these factors correlating to the enzymatic hydrolysis were evaluated through mathematical analysis. Among these factors, the fibrillation degree has the profoundest impact on the enzymatic hydrolysis of wood fibers. Consequently, the mechanical refining aiming for a high fibrillation degree was feasible to enhance the enzymatic hydrolysis of lignocellulosic biomass. [ABSTRACT FROM AUTHOR]

Autohydrolysis pretreatment with different severity factors was performed on poplar chips prior to chemi-thermomechanical pulping (CTMP) in order to investigate the change in pH value and its effect on the autohydrolysis pretreatment. The results showed that the dissolution amount of acetic acid increased with raising the severity factor of the pretreatment and declining the size of poplar chips, respectively. Besides, a logarithmic relationship between the amount of acetic acid released in the autohydrolysis liquor (AHL) and pH value of the AHL was observed. The amounts of glucose and xylose (including those in the form of monomers, oligomers, and polysaccharides) as well as furfural and hydroxymethylfurfural (HMF) also depended on the pH value of the AHL to some extent. [ABSTRACT FROM AUTHOR]

Three different pre-extraction methods (i.e., acetic acid, sulfuric acid and sodium hydroxide) were used for the pretreatment followed by chemi-thermomechanical treatments and then enzymatic hydrolysis of wheat straw to produce fermentable sugars. The performance of enzymatic hydrolysis by the synergistic effect of pre-extractions and chemi-thermomechanical treatments was remarkable. Results showed that the pre-extraction combining with the chemi-thermomechanical treatments shorten the enzymatic hydrolysis time and improved the glucose yield at the same enzyme loadings. The chemical components, swelling ability, and crystallinity, as well as the surface morphology of the substrates were changed obviously. All of these changes can affect the accessibility of enzymes to cellulose in the substrates to a certain extent. [ABSTRACT FROM AUTHOR]

As the promising anode material of lithium-ion batteries (LIBs), SiO 2 has high theoretical capacity, but the volume expansion severely hinders its application. To address the challenge, inspired by the highly flexible spider-web architecture, the SiO 2 @carbonized polyaniline/carbonized 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibrils (SiO 2 @cPANI/cTOCNFs) composite was designed, and fabricated via carbonizing the freeze-dried SiO 2 @PANI/TOCNFs. The resultant SiO 2 @cPANI/cTOCNFs composite exhibited unique spider-web-like nanostructures, providing a double-layer carbon network to protect SiO 2 anode material. The results showed that, the SiO 2 @cPANI/cTOCNFs composite as anode material of LIBs offered a reversible capacity of 1103 mAh g−1 at a current density of 0.1 A g−1 after 200 cycles, and gave a capacity of 302 mAh g−1 after 1000 cycles at a current density of 1 A g−1, exhibiting excellent cycling stability. This study provides a strategy of spider-web-inspired cellulose nanofibrils networking polyaniline-encapsulated silica nanoparticles as anode material of LIBs. [Display omitted] • SiO2@cPANI/cTOCNFs composite was proposed and fabricated. • TOCNFs in composite provided a carbon protection layer and spider-web-like structure. • SiO2 anode material in the composite is protected by a double-layer carbon network. • SiO2@cPANI/cTOCNFs composite exhibited excellent electrochemical performance [ABSTRACT FROM AUTHOR]

Highlights: [•] We impart photochromatism into cellulose paper by impregnating stable spirooxazine (SO). [•] We examine polystyrene acrylic latex as the carrier/dispersant for the hydrophobic SO. [•] Latex-dispersed SO can significantly improve its photochromic efficiency. [ABSTRACT FROM AUTHOR]

• Mixed triploid poplar and acacia woodchips P-RC APMP was made. • The obtained pulp with the substitution of 50 wt% NaOH by MgO had an excellent bulk. • The bleaching effluent of the obtained pulp had a low COD. • The bleaching reaction rate depended on the concentration of bleaching reagents. • The magnitude of the dependent extent is [H 2 O 2 ] > [NaOH] > [MgO] > [Na 2 SiO 3 ]. In the present work, the H 2 O 2 bleaching with the substitution of 50 wt% NaOH by MgO as the alkali source in the high-consistency (HC) retention stage of mixed triploid poplar (Populus tomentosa Carr.) and acacia (Acacia confusa Merr.) woodchips P-RC APMP (preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp) was conducted. Meanwhile, the related bleaching reaction kinetics was well established. The obtained high-yield pulp presented a higher bleaching yield, improved bulk, favorable brightness and physical properties in comparison with the obtained pulp using 100 % NaOH as the alkali source. Most importantly, the chemical oxygen demand (COD) of the bleaching effluent was greatly decreased. The established bleaching kinetic equation is as following: dw dt = K [ H 2 O 2 ] 3.63 [ NaOH ] 1.08 [ MgO ] 0.57 [ Na 2 SiO 3 ] 0.05 w − 1.89 K = A·e –E/RT where the activation energy E =57.2 kJ/mol. It demonstrates that the bleaching reaction rate greatly depends on the concentration of primary bleaching reagents. The magnitude of the dependent extent is [H 2 O 2 ] > [NaOH] > [MgO] > [Na 2 SiO 3 ]. The rapid rise of the pulp brightness increment occurred in the first 35 min in the bleaching reaction. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) have been regarded as green solvents in the biorefinery of lignocellulosic biomass, but long duration time has severely limited efficiency. The microwave-assisted DES pretreatment along with enzymatic hydrolysis and high-pressure homogenization process was proposed to produce lignin-containing cellulose nanofibrils (LCNF) from corncob. Benefiting from microwave-assisted DES pretreatment, the duration time was greatly shortened; meanwhile the effects of different kinds of DES on the resultant LCNF were investigated. The results showed that, the microwave-assisted DES fabricated LCNF (M-LCNF) was successfully obtained, exhibiting good nano size, thermal stability, colloidal stability, and fluorescence. M-LCNF was further introduced into phytic acid (PA) enhanced poly(acrylamide- co -acrylic acid) (P(AM-co-AA)) network and constructed composite conductive hydrogels (PLP). The obtained hydrogels exhibited good mechanical strength, UV blocking ability, fluorescence, and conductivity. A simple battery assembled with the resultant PLP as electrolyte had an out voltage of 2.41 V. The composite conductive hydrogel showed good sensing performance towards different stimuli (e.g., stretching and compression) and human motions in real time. It is expected that this research would provide an alternative way for green fabrication of LCNF and potential application of LCNF in flexible sensors. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A ternary DES was prepared, explored and compared with binary ones. • Microwave-assisted DES pretreatment was applied for lignin processing. • Lignin has been improved such as purity, dispersity and thermal stability. • The interaction between ternary DES and lignin was analyzed by MD simulation. • Dissolution mechanism of microwave-assisted ternary DES on lignin was proposed. Lignin is the most abundant natural aromatic macromolecule in the nature, but its high value-added utilization has been seriously hindered by the highly random and branched structures and the high difficulty in separation and purification. A microwave-assisted ternary deep eutectic solvent (DES) composed by formic acid, lactic acid and choline chloride was developed for lignin pretreatment. The effects of three types of DES on main characteristics of lignin were investigated, and the corresponding dissolution mechanism was proposed. The results showed that, the microwave-assisted ternary DES pretreatment showed an obvious improvement on main characteristics of regenerated lignin, e.g., a higher purity, lower molecular weight with reduced dispersity, improved thermal stability, higher phenolic hydroxyl content, and increased antioxidative activity in comparison with control. It is expected that the lignin macromolecular can be facile regulated and upgraded by the proposed ternary DES. [ABSTRACT FROM AUTHOR]

Research on nanocomposite film from natural polymers such as cellulose and chitosan is of great importance to promote the development and highly efficient utilization of green and renewable bioresources. In this study, enzymatic pretreatment cellulose nanofibril (ETCNF) derived from licorice residues was prepared, and further processed into nanocomposite film with addition of chitosan nanofibril (CHN). This study focused on the effects of CHN dosage on the main properties of resultant nanocomposite film in terms of crystallinity, thermal stability, light transmittance, hydrophobicity, mechanical properties, and antibacterial activity. The results showed that ETCNF/CHN nanocomposite film exhibited good hydrophobicity especially at higher dosage of CHN, good light transmittance and mechanical properties (tensile strain can reach 39.6 MPa for ETCNF/CHN-10.0%). The as-prepared ETCNF/CHN nanocomposite film also showed good antibacterial activity against Escherichia coli. It was expected that the ETCNF/CHN nanocomposite film would help to realize transformation and high value-added utilization of these biomass residues. • Cellulose nanofibril was prepared from licorice residues. • ETCNF/CHN nanocomposite film was successfully prepared and evaluated. • Effects of CHN dosage on properties of nanocomposite film were evaluated. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is regarded as an ideal renewable resource for replacing traditional fossil fuels. Corncob residues (CRs) generated after hemicelluloses pre-extraction of corncobs were potential feedstocks to produce lignin-based products. Three lignin fractions, i.e., dioxane lignin (DL), milled-wood lignin (MWL), and enzymatic mild acidolysis lignin (EMAL), were isolated from CRs and characterized by HPLC, GPC, FT-IR, NMR, and TGA to reveal characteristics of CRs lignin to better understand its potential applications. The results showed that the yield of DL, MWL and EMAL were 12.8%, 14.7% and 15.6%, respectively. The molecular weight of DL, MWL and EMAL were 2001, 5391, and 2629 g/mol, respectively. The EMAL and MWL had similar structural features including guaiacyl and syringyl units, β -O-4′ aryl ether, p -coumaric acids, ferulates, and phenylcoumarans, while the structure of DL was relatively simple. It is expected that this work will provide some useful information for the utilization of CRs in view of biorefinery. Unlabelled Image • Dioxane lignin, milled-wood lignin, and enzymatic mild acidolysis lignin were isolated from corncob residues. • Lignin fractions were completely characterized by HPLC, GPC, FT-IR, NMR, and TGA. • Wet grinding pretreatment was applied to improve enzymatic hydrolysis to promote the separation of lignin. • EMAL from CRs was obtained with high yield and small structural modification. [ABSTRACT FROM AUTHOR]

Highlights • CQDs were synthesized using hydrothermal method from corncob residues. • Nitrogen doping improved the fluorescence intensity and stability of CQDs. • CQDs were characterized and used for detecting metal ions. • E-N-CQDs were the most sensitive to Fe(III) with detection limit of 0.75 μmol L−1. Abstract Carbon quantum dots (CQDs) have been attracting extensive attention due to their chemical inertness, high water solubility, size effect, non-toxicity, photoluminescence reaction, photo-induced electron transfer, and tunable light emissions, among other attributes. In the study, the CQDs were synthesized using a simple, green, energy-saving, and efficient hydrothermal method from corncob residues (CRs) obtained after hemicelluloses pre-extraction of corncobs, and the enzymatically hydrolyzed corncob residues (EHCRs). The resultant CQDs were characterized and their applications in detection of metal ions were investigated. The results showed that CRs and EHCRs were good sources for CQDs; the nitrogen doping improved the fluorescence intensity and stability of CQDs; the nitrogen-doped CQDs from EHCRs (E-N-CQDs) exhibited the strongest fluorescence compared with other CQDs; the E-N-CQDs had a strong emission at a wavelength of 414 nm and an optimal excitation wavelength of 318 nm, the strongest fluorescence intensity was found at pH 10.0; the E-N-CQDs were the most sensitive to Fe(III) with the detection limit of 0.75 μmol L−1, which was much lower than the concentration of Fe(III) in human blood (7.52 − 11.82 mmol L−1). The developed E-N-CQDs concept may provide a novel method for the detection of Fe(III) in human blood. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two approaches were applied for delignification of corncob residues. • CNF was successfully extracted from corncob residues and characterized. • Cellulose nanopaper from CNF of corncob residues was fabricated. • Cellulose nanopaper exhibits good strength, optical and thermal properties. Abstract In this study, a strong and optically transparent nanopaper was fabricated from cellulose nanofibril (CNF) of corncob residues, an abundant byproduct from the processing of corncobs. Two processes were applied to successfully generate CNF from corncob residues. The resultant CNF mainly consists of fibers with diameter (height) of about 1.0 − 5.0 nm on average. The results showed that the as-prepared cellulose nanopaper (CNP) exhibited good strength, optical and thermal properties, with the tensile strength and tensile fracture strain of CNP being 65.3 MPa and 2.3%, respectively; the optical transmittance was close to 90% in the visible range; the highest degradation peak temperature was about 290 °C; the water contact angle at 30 s was 68.2°; A-CNP showed much higher optical properties and hydrophobicity, similar thermal ability, but slightly lower strength properties, compared with B-CNP. It can be seen that corncob residues are suitable choice of raw material for cellulose nanopaper, and is expected to find similar applications in flexible electronics and energy products as those of other raw materials used for this purpose. [ABSTRACT FROM AUTHOR]

Highlights • The pretreatment using MgCl 2 had a strong degradation effect on hemicellulose. • For enzymatic hydrolysis, the CYC could come up to 99.5% in some cases. • Hemicellulose degradation kinetics followed a first-order homogeneous reaction. Abstract Pretreatment using an acid salt is a novel technology for biomass conversion, which not only improves the following enzymatic efficiency but also decreases the equipment corrosion. In the present work, MgCl 2 was used as a pretreatment for enzymatic saccharification. After pretreatment, the solid substrate (SS) and pretreatment liquor (PL) were characterized, and the SS was enzymatically hydrolyzed to evaluate the conversion yield of cellulose (CYC). The results showed that the pretreatment using MgCl 2 had a strong degradation effect on hemicellulose, whose removal rate was nearly 100% in certain cases. After pretreatment, the efficiency of the enzymatic SS saccharification increased, such that the CYC was as high as 99.5%. The degradation kinetics of hemicellulose and cellulose both followed first-order homogeneous reactions, and the reaction activation energies E a were 46.63 kJ/mol and 82.26 kJ/mol, respectively. The suitable pretreatment conditions were as follows: 0.2 mol/L MgCl 2 at 210 °C for 20 min. [ABSTRACT FROM AUTHOR]

Carboxylated chitosan oligosaccharide (C–COS) was prepared by selective oxidation of chitosan oligosaccharide (COS) using laccase/2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) system to change its hydroxyl group on C6 to carboxyl group. Free radical-induced in vitro lipid oxidation experiments were performed using linoleic acid as the experimental subject. Inhibitory effects of COS and C–COS on lipid peroxidation were assessed by comparing the generation of a conjugated diene, MDA, and superoxide. Combining FTIR, 1H NMR, and GC-MS for structural analysis. Results show that C–COS and COS treatment suppressed lipid oxidation, and C–COS has better inhibition effects than COS. The primary inhibition mechanism lies in the carboxylic acid root of C–COS on C6 chelates with metal ions, reducing the generation of free radicals. Meanwhile, it exposes more C2 amino sites outside the sugar chain, promoting the capture of free radicals. This two-way action plays a synergistic role, effectively inhibiting free radicals from attacking fatty acids, avoiding lipid peroxidation. [Display omitted] • C–COS were prepared by oxidizing the hydroxyl group at C6 position of COS into carboxyl group. • C–COS perform better anti lipid oxidation efficiency than COS. • The mechanism for inhibiting lipid oxidation derived from the synergistic effect of amino and carboxyl groups. [ABSTRACT FROM AUTHOR]

In this work, poplar wood chips (PWCs) were subjected to autohydrolysis pretreatment with different levels of intensity, and the autohydrolyzed PWCs were used to make chemi-thermomechanical pulp (CTMP). The changes of the lignin structure of PWCs and the bleachability of the CTMP with autohydrolyzed PWCs as raw materials were both investigated. The results showed that the lignin structure changed to some extent in both CTMP pulping and the following bleaching process. The contents of conjugated carbonyl and quinone groups in the lignin structure were negatively correlated with the CTMP bleachability. Compared to the quinone groups, the conjugated carbonyl groups had a much greater impact on the bleachability. The present work would play a vital role for the application of autohydrolysis to the poplar CTMP pulping and the subsequent bleaching processes. [Display omitted] • Poplar wood chips (PWCs) were autohydrolyzed with different intensity levels. • Autohydrolyzed PWCs were used to make bleached chemi-thermomechanical pulp (CTMP). • Changes in lignin structure of PWCs and the CTMP bleachability were both explored. • Autohydrolysis was beneficial to the bleachability as the CHF did not exceed 10.77. • Conjugated carbonyl had bigger impact on CTMP bleachability than quinone group. [ABSTRACT FROM AUTHOR]

Abstract: Pre-extraction of hemicelluloses prior to pulping and conversion of the extracted hemicelluloses to other by-products will provide additional revenues to traditional pulp and paper industry. The effects of hemicelluloses pre-extraction with sulfuric acid on aspen (Populus tremuloides) chemi-thermomechanical pulp (CTMP) properties were investigated in this study. The sulfuric acid pre-extraction resulted in a release of 11% of hemicelluloses (determined as xylan) and acetic acid, especially at the second press-impregnation stage. Compared with CTMP without acid pre-extraction, the acid pre-extraction significantly reduced refining energy to a given freeness, and the pulps produced from acid pre-extracted chips have lower shives, higher strength properties except zero-span breaking length, lower bulk, but lower brightness at a similar specific refining energy. This study provides useful information for integration of biorefinery in mechanical pulp mills in the future. [Copyright &y& Elsevier]

Lignocellulosic biomass-derived nanocellulose has been attracting more and more attentions due to its distinguished advantages and various applications, but its development has been restricted by the preparation especially with environmental friendly approach. Herein, lignin-containing cellulose nanofibrils (LCNF) was prepared from corncob via the combined pretreatment of choline chloride-based DES (ChCl-DES) and enzymatic hydrolysis followed by high-pressure homogenization. The effects of different types of ChCl-DES on the properties of LCNF were investigated and compared. The results showed that LCNF can be successfully fabricated through the combined pretreatments; the LCNF had an average diameter of 60–90 nm, exhibited good fluorescence, high thermal stability (up to 353 °C of T max), hydrophobicity, stability, and redispersibility in organic solvent; AC-LCNF showed well oriented arrangement, the highest hydrophobicity and fluorescence, and distinguished redispersibility especially in DMSO. ChCl-DES as one green and sustainable approach would realize efficient separation and high value-added utilization of agricultural residues. [Display omitted] • LCNF was successfully prepared from corncob via combined pretreatment. • Choline chloride-based DES was effectively used to pretreat corncob. • Different types of ChCl-DES on the properties of LCNF were explored and compared. • LCNF had good properties such as size, fluorescence, and thermal stability. • AC-LCNF had good arrangement, fluorescence intensity, and redispersibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrothermal & chemi-mechanical pretreatment greatly improved enzymatic hydrolysis. • Different combined pretreatments on enzymatic hydrolysis efficiency were compared. • HFM pretreatment showed the highest enzymatic hydrolysis performance. • Adsorption kinetics of enzymes on different substrates were investigated. • Adsorption mechanism of enzymes on different substrates was summarized. An integration of different pretreatments is important to overcome recalcitrance and realize efficient bioconversion of lignocellulosic biomass. This study aims at the effects of combination of hydrothermal pretreatment and different chemi-mechanical pretreatments on enzymatic hydrolysis, and understanding the enzymes adsorption mechanism. The combination of hydrothermal and chemi-mechanical pretreatments effectively improved the enzymatic hydrolysis of poplar substrates, in which the enzymatic hydrolysis of substrates pretreated by hydrothermal pretreatment + Fenton pretreatment + mechanical refining (HFM) was the highest (92.39% of glucose conversion yield, and 20.88 g/L of glucose concentration). The substrates' main characteristics were obviously changed after combined pretreatments, such as swelling ability and specific surface area of substrates were increased. The Langmuir adsorption model (R2 > 0.98) and pseudo second-order adsorption kinetic model (R2≈1) were well suitable to describe the adsorption of enzymes on substrates, meanwhile the adsorption mechanism was summarized. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lignin-derived GQDs were prepared via phosphous acid-assisted hydrothermal process. • P-LGQDs have excellent electronic, optical properties, and pH-responsiveness. • P-LGQDs/g-C 3 N 4 shows good photocatalytic degradation ability for MB & model lignin. • Degradation products such as phenyl formate can be generated from model lignin. Value- added utilization of carbon-rich lignin has become an urgent and attractive research topic due to its abundance, low cost, and sustainability. How to convert lignin in an efficient and green strategy is the bottleneck limiting its valorization. Herein, a phosphorous acid (P) assisted hydrothermal process to produce lignin-derived graphene quantum dots (P-LGQDs) was developed. The as-prepared P-LGQDs was comprehensively characterized, and explored in photocatalysis. The P-LGQDs have a narrow particle size distribution, excellent electronic and optical properties, and a good pH-responsiveness. The P-LGQDs was further used to construct P-LGQDs/g-C 3 N 4 heterojunction, showing excellent photocatalytic degradation ability towards methylene blue and model lignin (94.6 % and 93.1 %, respectively). This present study offers a universal strategy for the value-added utilization and valorization of lignin. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Pretreatment of NH 4 Cl impregnation and refining was environment friendly and low energy consumption. • 97.4 % of the xylose was recovered to improve the utilization of all-components from lignocellulose. • Energy consumption of the refining was hugely decreased by NH 4 Cl impregnation. • Bioethanol yield and recovery rate of xylose were 190 and 151 g/kg wood, respectively. A combined pretreatment of NH 4 Cl impregnation and refining was developed to recover the fermentable sugars and improve the bioethanol yield. The xylose was recovered to decrease the cost of bioethanol production, moreover, the impregnation using nonmetal salt had little influence on the environment, and the energy consumption of the refining process was hugely reduced by the impregnation. The results showed that a high-temperature, short-time impregnation (170 °C, 10 min) led mainly to hemicelluloses degradation, where 97.4 % of the xylose was recovered from the impregnation liquor. 97.9 % of the cellulose in the refined solid substrate (SS) was converted to glucose by enzymatic hydrolysis, and 80.3 % of which was further fermented to bioethanol. The pretreatment energy efficiency was up to 260 g sugar/MJ, nearly three times higher than that using H 2 O impregnation and refining. Finally, the bioethanol yield (BY) and the xylose recovery reached to 189.75 and 150.95 g/kg wood, respectively. [ABSTRACT FROM AUTHOR]

An efficient and low-cost approach to preparing CNFs with succinic acid hydrolysis and NaClO 2 oxidation is explored. High-temperature-short-time hydrolysis can depolymerize the cellulose, whereas the dispersibility of the CNFs is hugely enhanced by NaClO 2 oxidation under alkaline condition. The degradation of cellulose in succinic acid hydrolysis follows first-order reaction kinetics and is severely influenced by the hydrolysis temperature, moreover, the molecular chains of the cellulose are seriously cracked under the optimized condition. The NaClO 2 oxidation greatly improves the zeta potential (−36.2 mV) and the dispersibility of the CNFs. The obtained CNFs have an ultimate yield of 94.6%, and the diameter distribution is mainly within 20–40 nm. In addition, some amount of carboxyl groups in the cellulose will be instead of the hydroxyl groups, and the crystallinity of the CNFs is significantly increased. • Succinic acid hydrolysis and NaClO 2 oxidation were utilized to prepare CNFs. • High-temperature-short-time hydrolysis could control the cellulose degradation. • NaClO 2 oxidation greatly improves the dispersibility of CNFs. • The yield of CNFs was about 94.6%, with a diameter distribution of 20–40 nm. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cotton fibres and bacteriostatic agents were combined by ester bonds. • XPS was used to detect the presence of silver ions in bacteriostatic agents. • Bacteriostatic fibre had excellent washing durability. The laccase/TEMPO system was employed to oxidise the C6 primary hydroxyl group on the chitosan (CS) to form a carboxyl group to obtain oxidised chitosan (C-COS). The silver-oxidised chitosan complex(C-COS-Ag) was prepared by reacting C-COS with silver nitrate, then C-COS-Ag and cotton fibres were subjected to a reaction to prepare bacteriostatic fibres. FT-IR and XPS analysis showed that: Ag+ and C-COS were combined in these forms: Ag, [Ag(NH 3) 2 ] OH, -COOAg, and Ag 2 O. C-COS-Ag was combined with cotton fibres by way of ester bonds. The inhibition zone of bacteriostatic fibres was all greater than 11 mm. After 50 washing tests, the bacteriostatic effect of bacteriostatic fibres remained at above 99 %. The amount of silver ions that had migrated from the bacteriostatic fibre was 3.336 mg/kg. [ABSTRACT FROM AUTHOR]

• A porous SiO 2 /C composite was fabricated using wood pulp fiber as scaffold. • Alkali pretreatment could endow prepared SiO 2 /C composite with tubular morphology. • Si element can be distributed on the surface and inner wall of the SiO 2 /C composite. • The prepared SiO 2 /C composite exhibited a high initial coulombic efficiency. The microfibrils of wood pulp fibers in plant cell wall with an intrinsically regular and interlaced arrangement offer a stable porous structure. They could also provide outstanding mechanical strength and promote conductivity for Si-based materials. Upon these benefits, a method using wood pulp fibers to fabricate SiO 2 /C composite is proposed. In this work, the alkali pretreatment interfering hydrogen bonds in wood pulp fibers in situ results in an enlarged spatial distance among cellulose microfibrils, exposing more free-surface. This empowered homogenously inlaid SiO 2 distribution along the carbon skeleton in the subsequent carbonization process. A highly mesoporous and the tubular morphology was achieved in the fabricated SiO 2 /C composite. Furthermore, a high initial coulombic efficiency of 84.9 % and reversible specific capacity of 1130 mA h g−1 with a coulombic efficiency of 98.8 % after 200 cycles at a current density of 0.1 A g−1 was obtained. [ABSTRACT FROM AUTHOR]

• Wet grinding pretreatment enhanced enzymatic hydrolysis of corncob residues. • Adsorption behavior of cellulase on wet ground corncob residues was studied. • Langmuir adsorption and pseudo second-order adsorption model were suitable. • Relationships between adsorption and main characteristics were established. • Significance of main characteristic of corncob residues on adsorption was found. Understanding the adsorption behavior and the interaction between substrates and enzymes are critical to improving enzymatic hydrolysis efficiency and reducing bioconversion cost. Herein, the adsorption of cellulase on wet ground corncob residues was studied, and the effects of main characteristics of wet ground corncob residues on adsorption capacity were quantitatively analyzed with the combination of principal component analysis and multiple linear regression models. The results showed that the adsorption of cellulase on wet ground corncob residues was fitted well with Langmuir isotherm adsorption and pseudo second-order kinetics model, the adsorption rate and adsorption capacity were greatly enhanced with increasing grinding time; the multiple linear regression models describing the relationship between main characteristics of corncob residues and adsorption capacity to cellulase were established; the significance of these characteristics were in the following order: average particle size, crystallinity index, specific surface area, surface lignin concentration, water retention value, and surface charge density. [ABSTRACT FROM AUTHOR]

• Hydrothermal and Fenton pretreatment synergistically promote enzymatic hydrolysis. • Fenton pretreatment can help to solve inhibition of pseudo lignin problem. • Pre-hydrolysates provide additional revenues such as XOS, GOS, and xylose. • Main substrates' characteristics were changed by combined pretreatments. The combination of different pretreatment methods can effectively overcome recalcitrance of lignocellulosic biomass to ensure its highly efficient conversion into bio-based products. In this study, the combined pretreatments of chemical methods (hydrothermal treatment and Fenton treatment) with mechanical refining were used to improve the enzymatic hydrolysis efficiency of poplar branches. The results indicated that hydrothermal pretreatment and Fenton pretreatment can effectively improve the enzymatic hydrolysis of poplar substrates, e.g., the maximum glucose conversion yield and glucose concentration reached 92.4% and 20.8 g/L, respectively. The pre-hydrolysates contained some valuable components such as monosaccharides, oligosaccharides, acetic acid, furfural, and hydroxymethylfurfural. The main characteristics (specific surface area, water retention value, fines content, and surface lignin concentration) of poplar substrates were obviously changed by the combined pretreatment, which benefit the enzymatic hydrolysis. [ABSTRACT FROM AUTHOR]