Heteropolyacid promoted lignin-MOF derived spherical catalyst for catalytic hydrogen transfer of 5-hydroxymethylfurfural.

Catalytic conversion of biomass-derived value-added chemicals was of great significance for the utilization of renewable biomass resources to instead of fossil chemicals. Biomass-derived lignin was regarded as an important support and 5-hydroxymethylfurfural (HMF) was a vital platform chemical derived from cellulose. Herein, a series of lignin-MOF hybrid catalysts were prepared and modified with different heteropolyacids (HPAs), which were then successfully introduced into the selective conversion of HMF to 5-hydroxymethylfurfuryl alcohol (MFA). The effect of different HPA, calcination temperature, etc. were all studied, and all catalysts were well characterized. It was confirmed that silicotungstic acid modified catalyst (Ni3Co-MOF-LS@HSiW) exhibited the best catalytic performance, while the highest conversion of HMF was up to 100%, with the best MFA yield of 86.5%. The finding in this study could provide novel insights for the utilization of lignin and preparation of value-added biomass-derived chemicals.

Direct synthesis of a lithium carboxymethyl cellulose binder using wood dissolving pulp for high-performance LiFePO4 cathodes in lithium-ion batteries.

Lithium carboxymethyl cellulose (CMC-Li) is a promising novel water-based binder for lithium-ion batteries. The direct synthesis of CMC-Li was innovatively developed using abundant wood dissolving pulp materials from hardwood (HW) and softwood (SW). The resulting CMC-Li-HW and CMC-Li-SW binders possessed a suitable degree of substitutions and excellent molecular weight distributions with an appropriate quantity of long- and short-chain celluloses, which facilitated the construction of a reinforced concrete-like bonding system. When used as cathode binders in LiFePO4 batteries, they uniformly coated and dispersed the electrode materials, formed a compact and stable conductive network with high mechanical strength and showed sufficient lithium replenishment. The prepared LiFePO4 batteries exhibited good mechanical stability, low charge transfer impedance, high initial discharge capacity (∼180 mAh/g), high initial Coulombic efficiency (99 %), excellent cycling performance (<3% loss over 200 cycles) and good rate capability, thereby outperforming CMC-Na and the widely used cathode binder polyvinylidene fluoride.

Unveiling the Dissolution Regularities of the Lignin-Carbohydrate Complex in Bamboo Cell Walls during Alkali Pretreatment.

Bamboo is a promising biomass resource. However, the complex multilayered structure and chemical composition of bamboo cell walls create a unique anti-depolymerization barrier, which increases the difficulty of separation and utilization of bamboo. In this study, the relationship between the connections of lignin-carbohydrate complexes (LCCs) within bamboo cell walls and their multilayered structural compositions was investigated. The chemical composition, structural properties, dissolution processes, and migration mechanisms of LCCs were analyzed. Alkali-stabilized LCC bonds were found to be predominantly characterized by phenyl glycoside (PhGlc) bonds along with numerous p-coumaric acid (PCA) linkage structures. As demonstrated by the NMR and CLSM results, the dissolution of the LCC during the alkaline pretreatment process was observed to migrate from the inner secondary wall (S-layer) of the bamboo fiber cell walls to the cell corner middle lamella (CCML) and compound middle lamella (CML), ultimately leading to its release from the bamboo. Furthermore, the presence of H-type lignin-FA-arabinoxylan linkage structures within the bamboo LCC was identified with their primary dissolution observed in the S-layer of the bamboo fiber cell walls. The study results provided a clear target for breaking down the anti-depolymerization barrier in bamboo, signifying a major advancement in achieving the comprehensive separation of bamboo components.

Anthraquinone-based polymer modified BiVO4 photoanode with strong electron-withdrawing functional groups for boasting photoelectrochemical water oxidation.

The photoelectrochemical (PEC) performance ofBiVO4 is limited by sluggish water oxidation kinetics and severe carrier recombination. Herein, a novel high-performance BiVO4/NiFe-NOAQ photoanode is prepared by a simple one-step hydrothermal method, using BiVO4 and 1-Nitroanthraquinone (NOAQ) as raw materials. The BiVO4/NiFe-NOAQ photoanode has an excellent photocurrent density of 5.675 mA cm-2 at 1.23 VRHE, which is 3.35 times higher than that of the pure BiVO4 (1.693 mA cm-2) photoanode. The BiVO4/NiFe-NOAQ shows a significant improvement in charge separation efficiency (86.12 %) and charge injection efficiency (87.86 %). The improvement is ascribable to the NiFe-NOAQ form a type II heterojunction with BiVO4 to inhibit carrier recombination. More importantly, the kinetic isotope experiment suggests that the proton-coupled electron transfer (PCET) process can enhance the charge transfer of BiVO4/NiFe-NOAQ. The contact angle measurements show that modifying functional groups enhanced the hydrophilicity of BiVO4/NiFe-NOAQ, which can further accelerate the PCET process. The XPS and PL results as well as the tauc plot indicate that the strong electron-withdrawing ability of -NO2 which can promote the extension of π conjugation, results in more π electron delocalization and produces more efficient active sites, thus achieving efficient photoelectrochemical water oxidation.

Efficient degradation of lignin by chlorine dioxide and preparation of high purity pulp fiber.

High-purity pulp fibers can be obtained by using chlorine dioxide to oxidize lignin. However, organic halogen compounds (AOX) are generated from chlorination side reactions during the lignin oxidation process. In this study, phenolic lignin model compounds with different substituents were selected. The effects of substituent position on the production of free radicals and oxidative ring opening in benzene rings were analyzed. It was found that the structural transformation of lignin and the reaction consumption of ClO2 were significantly changed under high concentration of ClO2. The molar consumption ratio of compound to ClO2 was increased from 1:2 to 1:3. Quinone, an intermediate product that promotes the formation of phenoxy radicals, was found to be stabilized in the reaction. This is attributed to that the benzene ring of lignin is activated through long-range electrostatic interactions. The formation of free radicals and the oxidative ring-opening reaction of benzene rings were facilitated. The efficient oxidation of lignin by ClO2 was fulfilled. Chlorination reactions of lignin were suppressed at elevated oxidation efficiency. The pollution load of wastewater was significantly reduced. AOX generation was reduced by 69.27 %. This provides a new method for efficient oxidative degradation of lignin and preparation of high purity pulp fiber.

A comprehensive review of chloropropanol analytical method in the context of food safety.

Chloropropanols are among the major food contaminants, and quantifying their content in food is a key food-safety issue. In response to the demand for highly sensitive and selective analysis, the scientific community is committed to continuous innovation and optimization of various analytical techniques. This paper comprehensively reviews the latest developments in chloropropanol analysis technologies and systematically compares and analyzes the working principles, application conditions, advantages, and challenges of these methods. Gas chromatography-mass spectrometry is the preferred choice for chloropropanol analysis in complex sample matrices owing to its high resolution, sensitivity, and accuracy. Electrochemical methods provide strong support for the real-time monitoring of chloropropanols because of their high selectivity and sensitivity towards electrochemically active molecules. Other techniques offer innovative solutions for the rapid and accurate analysis of chloropropanol at different levels. Finally, innovative directions for the development of chloropropanol analysis methods for food safety are highlighted.

Green Process for Producing Xylooligosaccharides by Using Sequential Auto-hydrolysis and Xylanase Hydrolysis.

Xylooligosaccharides (XOS), as prebiotic oligomers, are increasingly receiving attention as high value-added products produced from lignocellulosic biomass. Although the XOS contains a series of different degrees of polymerization (DP) of xylose units, DP 2 and 3 (xylobiose (X2) and xylotriose (X3)) are regarded as the main active components in food and pharmaceutical fields. Therefore, in the study, in order to achieve the maximum production of XOS with the desired DP, a combination strategy of sequential auto-hydrolysis and xylanase hydrolysis was developed with corncob as raw material. The evidences showed that the hemicellulosic xylan could be effectively decomposed into various higher DP saccharides (> 4), which were dissolved into the auto-hydrolysate; sequentially, the soluble saccharides could be rapidly hydrolyzed into XOS with desired DP by xylanase hydrolysis. Finally, a maximum XOS yield of 56.3% was achieved and the ratio of (X2 + X3)/XOS was over 80%; meanwhile, the by-products could be controlled at lower levels. Overall, this study provides solid data that support the selective and precise preparation of XOS from corncob, vigorously promoting the application of XOS as functional sugar products.

Electrochemical surface reconstruction of Prussian blue-modified nickel sulfide to form iron-nickel bilayer hydroxyl oxides for efficient and stable oxygen evolution reaction processes.

The oxygen evolution reaction (OER) is an important semi-reaction in the electrocatalytic water splitting for hydrogen energy production, and the development of efficient and low-cost electrocatalysts to solve the problem of slow 4-electron transport kinetics in the OER process is key. In this work, a pre-electrocatalyst with the heterogeneous interfacial structure, Prussian blue-modified nickel sulfide with sulfur vacancies (PB/NS-Sv), was designed and then converted to iron-nickel bilayer hydroxyl oxides in oxygen-rich vacancies (FeOOH/NiOOH-Ov@NS) through electrochemical oxidative reconstruction to obtain a truly stable and efficient active material. The study utilized in situ Raman to observe the transition from PB/NS-Sv to FeOOH/NiOOH-Ov@NS during the reaction. The electronic density of states in FeOOH/NiOOH-Ov@NS is regulated by the bilayer hydroxyl metal oxide synergistic effect and the abundant oxygen defect of Mental-OOH-Ov, which significantly improves OER catalytic performance. FeOOH/NiOOH-Ov@NS requires a low overpotential of only 257 mV in 1 mol/L KOH at 100 mA cm-2 current density, has a small Tafel slope of 35.2 mV dec-1 and has excellent stability for 150 h at 100 mA cm-2 current density, making it a promising candidate for industrial applications.

Selective separation of hemicellulose from poplar by hydrothermal pretreatment with ferric chloride and pH buffer.

As an environmentally friendly lignocellulosic biomass separation technology, hydrothermal pretreatment (HP) has a strong application prospect. However, the low separation efficiency is a main factor limiting its application. In this study, the poplar components were separated using HP with ferric chloride and pH buffer (HFB). The optimal conditions were ferric chloride concentration of 0.10 M, reaction temperature of 150 °C, reaction time of 15 min and pH 1.9. The separation of hemicellulose was increased 34.03 % to 77.02 %. The pH buffering resulted in the highest cellulose and lignin retention yields compared to ferric chloride pretreatment (FC). The high efficiency separation of hemicellulose via HFB pretreatment inhibited the degradation of xylose. The hydrolysate was effectively reused for five times. The fiber crystallinity index reached 60.05 %, and the highest C/O ratio was obtained. The results provide theoretical support for improving the efficiency of HP and promoting its application.

Effect of Substituents on Molecular Reactivity during Lignin Oxidation by Chlorine Dioxide: A Density Functional Theory Study.

Lignin is a polymer with a complex structure. It is widely present in lignocellulosic biomass, and it has a variety of functional group substituents and linkage forms. Especially during the oxidation reaction, the positioning effect of the different substituents of the benzene ring leads to differences in lignin reactivity. The position of the benzene ring branched chain with respect to methoxy is important. The study of the effect of benzene substituents on the oxidation reaction's activity is still an unfinished task. In this study, density functional theory (DFT) and the m062x/6-311+g (d) basis set were used. Differences in the processes of phenolic oxygen intermediates formed by phenolic lignin structures (with different substituents) with chlorine dioxide during the chlorine dioxide reaction were investigated. Six phenolic lignin model species with different structures were selected. Bond energies, electrostatic potentials, atomic charges, Fukui functions and double descriptors of lignin model substances and reaction energy barriers are compared. The effects of benzene ring branched chains and methoxy on the mechanism of chlorine dioxide oxidation of lignin were revealed systematically. The results showed that the substituents with shorter branched chains and strong electron-absorbing ability were more stable. Lignin is not easily susceptible to the effects of chlorine dioxide. The substituents with longer branched chains have a significant effect on the flow of electron clouds. The results demonstrate that chlorine dioxide can affect the electron arrangement around the molecule, which directly affects the electrophilic activity of the molecule. The electron-absorbing effect of methoxy leads to a low dissociation energy of the phenolic hydroxyl group. Electrophilic reagents are more likely to attack this reaction site. In addition, the stabilizing effect of methoxy on the molecular structure of lignin was also found.

Redox-active ligands enhance oxygen evolution reaction activity: Regulating the spin state of ferric ions and accelerating electron transfer.

Metal-organic frameworks (MOFs) are considered as one of the most promising catalysts for oxygen evolution reaction (OER). However, only a few have introduced redox-active ligands into MOFs and explored their role in the OER process. In this work, we synthesized FeNi DHBQ/NF using the redox-active ligand 2,5-dihydroxy-1,4-benzoquinone (DHBQ), which exhibited excellent redox activity and required only 207 and 242 mV overpotentials to achieve current densities of 10 and 100 mA cm-2. Our research confirms that (i) the doping of Fe leads to the formation of Ni â†’ O â†’ Fe electron transfer channels in the MOFs and stronger electron transfer, attributed to the stronger d-π conjugation between the metal center and the ligand and reduced the d-orbital crystal field splitting energy of Fe3+; (ii) the rate determination step (RDS) in the OER process of the catalyst is the formation of O*, while Fe and redox-active ligands effectively regulate the adsorption energy of oxygen-containing intermediates, reducing the energy barrier of the RDS; (iii) the redox-active ligands can act as "electron reservoirs" in the electrochemical process, making Ni more readily oxidized to Ni3+ or even Ni4+ at low potentials, which is beneficial to the subsequent OER process.

High-Strength, High-Water-Retention Hemicellulose-Based Hydrogel and Its Application in Urea Slow Release.

The use of fertilizer is closely related to crop growth and environmental protection in agricultural production. It is of great significance to develop environmentally friendly and biodegradable bio-based slow-release fertilizers. In this work, porous hemicellulose-based hydrogels were created, which had excellent mechanical properties, water retention properties (the water retention ratio in soil was 93.8% after 5 d), antioxidant properties (76.76%), and UV resistance (92.2%). This improves the efficiency and potential of its application in soil. In addition, electrostatic interaction and coating with sodium alginate produced a stable core-shell structure. The slow release of urea was realized. The cumulative release ratio of urea after 12 h was 27.42% and 11.38%, and the release kinetic constants were 0.0973 and 0.0288, in aqueous solution and soil, respectively. The sustained release results demonstrated that urea diffusion in aqueous solution followed the Korsmeyer-Peppas model, indicating the Fick diffusion mechanism, whereas diffusion in soil adhered to the Higuchi model. The outcomes show that urea release ratio may be successfully slowed down by hemicellulose hydrogels with high water retention ability. This provides a new method for the application of lignocellulosic biomass in agricultural slow-release fertilizer.

Simultaneous achievement of efficient hemicellulose separation and inhibition of lignin repolymerization using pyruvic acid treatment.

The efficiency of organic acid treatment in the conversion of lignocellulosic biomass fractions has been widely recognized. In this study, a novel green pyruvic acid (PA) treatment is proposed. The higher separation efficiency of eucalyptus hemicellulose was obtained at 4.0% PA and 150 °C. The hemicellulose separation yield was increased from 71.71 to 88.09% compared to glycolic acid (GA) treatment. In addition, the treatment time was significantly reduced from 180 to 40 min. The proportion of cellulose in the solid increased after PA treatment. However, the accompanying separation of lignin was not effectively controlled. Fortunately, a six-membered ring structure was formed on the diol structure of the lignin ß-O-4 side chain. Fewer lignin-condensed structures were observed. High-value lignin rich in phenol hydroxyl groups were obtained. It provides a green path for the simultaneous achievement of efficient hemicellulose separation and inhibition of lignin repolymerization using organic acid treatment.

Novel dual-action vanillic acid pretreatment for efficient hemicellulose separation with simultaneous inhibition of lignin condensation.

Aromatic acids play a selective role in the separation of hemicellulose. Phenolic acids have demonstrated an inhibitory effect on lignin condensation. In the current study, vanillic acid (VA), which combines the characteristics of aromatic and phenolic acids, is used to separate eucalyptus. The efficient and selective separation of hemicellulose is achieved simultaneously at 170 °C, 8.0% VA concentration, and 80 min. The separation yield of xylose increased from 78.80% to 88.59% compared to acetic acid (AA) pretreatment. The separation yield of lignin decreased from 19.32% to 11.19%. In particular, the ß-O-4 content of lignin increased by 5.78% after pretreatment. The results indicate that VA, as a "carbon positive ion scavenger", it preferentially reacts with the carbon-positive ion intermediate of lignin. Surprisingly, the inhibition of lignin condensation is achieved. This study provides a new starting point for the development of an efficient and sustainable commercial technology by organic acid pretreatment.

Is Neutrophil Lymphocyte Ratio, Platelet Lymphocyte Ratio or Red Blood Cell Distribution Width Associated with Risk of Mortality in Patients with Necrotizing Fasciitis.

Purpose: Neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), and red blood cell distribution width (RDW) are novel biomarkers to indicate the inflammatory/immune response, and demonstrated to be effective in diagnosis, severity evaluation, and prognosis in a variety of chronic or acute conditions. This study aims to examine whether NLR, PLR and EDW are independently associated with mortality in necrotizing fasciitis (NF). Methods: This study retrospectively enrolled patients diagnosed with NF and based on vitality status during hospitalization or within 30 days after discharge, survival and non-survival groups were defined. For distinctly comparing NLR, PLR, RDW and others, we enrolled the matched healthy controls of the same age and sex as the survivors of NF in a 1:1 ratio, which constituted the healthy control group. Comparisons were made between three groups. Variables tested with a P value < 0.10 were further entered into the multivariate logistic regression model to identify their independent association with mortality. Results: A total of 281 subjects were included, including 127 healthy controls, 127 survivors, and 27 nonsurvivors with NF, respectively, indicating a mortality rate of 17.5%. ROC analysis showed that the optimal cutoff value for NLR, PLR and RDW was 11.1, 196.0 and 15.5%, respectively, and was tested as significant only for the first two (P < 0.001, = 0.004). Multivariate logistic analysis showed that NLR ≥ 11.1 (OR, 2.51) and PLR ≥ 196.0 (OR, 2.09) were independently associated with an increased risk of mortality in NF patients, together with age ((OR, 1.28, for each 10-year increment), comorbid diabetes mellitus (OR, 2.69) and liver disease (OR, 1.86), and elevated creatinine level (OR, 1.21 for each 10 umol/L elevation). Conclusion: Elevated NLR and PLR are significant and independent predictors of mortality and can be considered for use when evaluating patients at risk of mortality.

Rapid and mild fractionation of hemicellulose through recyclable mandelic acid pretreatment.

The development of organic acid pretreatments from biological sources is essential to facilitate the progress of green and sustainable chemistry. In this study, the effectiveness of mandelic acid pretreatment (MAP) was analyzed for eucalyptus hemicellulose separation. 83.66% of xylose was separated under optimal conditions (temperature: 150 °C; concentration: 6.0 wt%; time: 80 min). The hemicellulose separation selectivity is higher than acetic acid pretreatment (AAP). The stable and effective separation efficiency (56.55%) is observed even after six reuses of the hydrolysate. Higher thermal stability, larger crystallinity index and optimized surface element distribution in the samples were demonstrated by MAP. Lignin condensation is effectively inhibited through MAP, as determined from the structural of different lignin. In particular, the demethoxylation of lignin by MA was found. These results open up a new way to construct a novel organic acid pretreatment for separating hemicellulose with high efficiency.

Overexpression of a gibberellin 20-oxidase gene in poplar xylem led to an increase in the size of nanocellulose fibrils and improved paper properties.

Cellulose, the major component of secondary cell walls, is the most abundant renewable long-chain polymer on earth. Nanocellulose has become a prominent nano-reinforcement agent for polymer matrices in various industries. We report the generation of transgenic hybrid poplar overexpressing the Arabidopsis gibberellin 20-oxidase1 gene driven by a xylem-specific promoter to increase gibberellin (GA) biosynthesis in wood. X-ray diffraction (XRD) and sum frequency generation spectroscopic (SFG) analyses showed that cellulose in transgenic trees was less crystalline, but the crystal size was larger. The nanocellulose fibrils prepared from transgenic wood had an increased size compared to those from wild type. When such fibrils were used as a reinforcing agent in sheet paper preparation, the mechanical strength of the paper was significantly enhanced. Engineering the GA pathway can therefore affect nanocellulose properties, providing a new strategy for expanding nanocellulose applications.

Effectiveness of the Endplate Reduction Technique Combined With Bone Grafting for the Treatment of Thoracolumbar Fractures by Using Posterior Short-Segment Fixation.

OBJECTIVE: This study aimed to examine the effect of the endplate reduction (EPR) technique combined with bone grafting for treating thoracolumbar burst fractures using posterior short-segmental fixation. METHODS: Patients with thoracolumbar fractures admitted between January 2018 and October 2021 were retrospectively analyzed, and those meeting the criteria were assigned to the EPR group and the intermediate screws (IS) group. The vertebral wedge angle (VWA), Cobb angle (CA), anterior vertebral body height (AVBH), middle vertebral body height (MVBH), upper endplate line (UEPL), upper intervertebral angle (UIVA), and upper intervertebral disc height (UIDH) indices were examined and compared preoperatively, first day postoperatively, as well as at 12 months postoperatively. RESULTS: The result indicated that the EPR group achieved better MVBH reduction (p < 0.001), UEPL reduction (p < 0.001), vertebral body fracture healing (p = 0.006), as well as implant breakage (p = 0.04) than the IS group; VWA (p < 0.001), CA (p = 0.005), AVBH (p < 0.001), MVBH (p < 0.001), UEPL (p < 0.001), and UIDH (p < 0.001) were lost after reduction less than those in the IS group. There was no significant difference in operative time (p = 0.315) and intraoperative bleeding (p = 0.274) between the 2 groups. CONCLUSION: The EPR group achieved better results in repositioning and maintaining MVBH and endplate morphology, with less correction loss after the reduction of the VWA, CA, AVBH, and endplate morphology. The EPR group exhibited a better healing pattern after vertebral fracture and disc degeneration was better relieved.

Pretreatment of poplar with eco-friendly levulinic acid to achieve efficient utilization of biomass.

Organic acid pretreatment is an effective method for green separation of lignocellulosic biomass. However, repolymerization of lignin seriously affects the dissolution of hemicellulose and the conversion of cellulose during organic acid pretreatment. Therefore, a new organic acid pretreatment, levulinic acid (Lev) pretreatment, was studied for the deconstruction of lignocellulosic biomass without adding additional additives. The preferred separation of hemicellulose was realized at Lev concentration 7.0%, temperature 170 °C, and time 100 min. The separation of hemicellulose increased from 58.38% to 82.05% compared with acetic acid pretreatment. It was found that the repolymerization of lignin was effectively inhibited in the efficient separation of hemicellulose. This was attributed to the fact that γ-valerolactone (GVL) is a good green scavenger of lignin fragments. The lignin fragments in the hydrolysate were effectively dissolved. The results provided theoretical support for creating green and efficient organic acid pretreatment and effectively inhibiting lignin repolymerization.

Template-directed growth of sustainable carboxymethyl cellulose-based aerogels decorated with ZIF-67 for activation peroxymonosulfate degradation of organic dyes.

A novel 3D advanced oxidation catalyst ZIF-67@C-CMC/rGO based on carboxymethyl cellulose (CMC) and reduced graphene oxide (rGO) was successfully synthesized by facile in-situ growth of Zeolitic imidazolate framework-67 (ZIF-67). C-CMC/rGO aerogel crosslinked by poly (methyl vinyl ether-alt-maleic acid)/polyethylene glycol system (PMVEMA/PEG) as the host material was prepared through a template-directed growth model and exhibited outstanding mechanical properties. The sustainable composite was successfully used as an efficient catalyst for activating peroxymonosulfate (PMS) to generate SO4-· and ·OH, then leads to the removal of organic contaminants. As a result, almost 100 % of 10 ppm MB/RhB solution can be degraded within 5 min due to the combination of catalyst aerogel and PMS. What's more, the aerogel showed a wide pH tolerance range from 4 to 9 and maintained up to 93 % of the contaminant removal rate compared to the initial value after four cycles. The ZIF-67@C-CMC/rGO aerogel with high load rate and excellent catalytic degradation performance not only solved the problem of dispersion and recovery of ZIF-67 particles, but also provided a new idea for the compound wastewater purification in sulfate radical-based advanced oxidation processes (SR-AOPs).