Publications by authors named "Meihong Niu"

Converting lignin into specific aromatic chemicals for utilization through depolymerization of lignin is an effective way to achieve high-value applications. There are many depolymerization methods that can do this, but there are problems such as harsh reaction conditions, low depolymerization efficiency and uncontrollable target products that need to be solved. This study reports a novel system for the oxidative depolymerization of alkali lignin using Fe- and Mn- modified TS-1 as a catalyst to assist in the highly selective production of vanillin.

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As the second most abundant biopolymer, lignin remains underutilized in various industrial applications. Various forms of lignin generated from different methods affect its physical and chemical properties to a certain extent. To promote the broader commercial utilization of currently available industrial lignins, lignin sulfonate (SL), kraft lignin (KL), and organosolv lignin (OL) are utilized to partially replace phenol in the synthesis of phenol formaldehyde (PF) adhesives.

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In this work, novel lignin-based nanoparticles (LβNPs) with high acidic tolerance were successfully prepared via electrostatic interaction between β-alanine and lignin nanoparticles. The effects of the mass ratio of lignin nanoparticles to β-alanine and pH value on the morphology and particle sizes of LβNPs were investigated with the aim of obtaining the ideal nanoparticles. The optimized LβNPs were spherical in shape with an average particle size of 41.

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With the growing global population and rapid economic development, the demand for energy and raw materials is increasing, and the supply of fossil resources as the main source of energy and raw materials has reached a critical juncture. However, our overexploitation and overconsumption of fossil resources have led to serious problems, including environmental pollution, climate change, and ecosystem destruction. In the face of these challenges, we must recognize the negative impacts of the shortage of fossil resources and actively seek sustainable alternative sources of energy and resources to protect our environment and sustainable development in the future.

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The poor water solubility, large particle size, and low accessibility of cellulose, the most abundant bioresource, have restricted its generalization to carbon dots (CDs). Herein, nitrogen and sulfur co-doped fluorescent carbon dots (N, S-CDs) were hydrothermally synthesized using cellulose nanocrystals (CNC) as a carbon precursor, exhibiting a small particle size and excellent aqueous dispersion. Thiourea was selected as a nitrogen and sulfur dopant to introduce abundant fluorescent functional groups into N, S-CDs.

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Enzymatic hydrolysis is a method to generate biofuel from biomass, and autohydrolysis is a popular method to pretreat biomass prior to enzymatic hydrolysis. The primary aim of the present study was to determine the role of lignin produced in the autohydrolysis process on the enzymatic hydrolysis of biomass. The HSQC and P NMR analyses confirmed that β-O-4 of lignin was reduced, while β-5, β-β, and S/G-ratio of lignin were increased with intensifying the hydrolysis intensity.

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The aim of this work was to study the sedimentary substances formed on the surface of auto-hydrolyzed wood chips. And its potential effect on the subsequent chemical pulping was then investigated by the analysis of surface morphology, benzene-alcohol extractive, absorbability and kraft pulping of wood chips hydrolyzed. The results showed that sediments on the surface of auto-hydrolyzed wood chips were microspheric and the amount of them increased with intensifying the severity of treatment.

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Novel modified cellulose/cellulose fibril (CF) beads (MCCBs) loaded with laccase were prepared to degrade polychlorinated biphenyls (PCBs) in wastewater. The proper porous structure in MCCBs was achieved by introducing nano CaCO₃ (as a pore forming agent) in cellulose/CF (CCBs) beads during the preparation process. Cellulose/CF composite beads were modified by maleic anhydride to introduce carboxyl groups.

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When using a combination of pre-extraction and chemical pulping, a high yield of sugar recovery and minimal negative effect on the subsequent pulping step are expected. In this work, the P factor was utilized to investigate the effect of auto-hydrolysis severity on sugar recovery, removal of the main component, and impact on the kraft pulping of acacia wood chips. Using a P factor of 235, 84.

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Biochars produced from two different wood species over a microwave assisted pyrolysis process were used as novel and green-based supports for immobilizing enzyme, laccase in particular. The results obtained from FT-IR, SEM and BET measurements indicated that Maple biochar with honeycomb structure has higher surface area and pore volume than Spruce biochar; and there exist O-H, C-H, C=O and C=C groups in biochars for potential chemical modification. The best laccase immobilization conditions identified from an orthogonal experiment were pH = 3, laccase concentration 16 g/L and contact time 8 h.

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In this study, alkaline sulfite pretreatment of corn stover was optimized. The influences of pretreatments on solid yield, delignification, and carbohydrate recovery under different pretreatment conditions and subsequent enzymatic hydrolysis were investigated. The effect of pretreatment was evaluated by enzymatic hydrolysis efficiency and the total sugar yield.

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