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Apple wood waste (AWW), mainly tree trucks, is collectible lignocellulosic biomass from orchard rotation. The biorefinery of AWW is challenging because of the hard and dense structure. In the present work, chemical composition determination and microstructure observation was performed for the first time on AWW. Alkali-preimpregnation-assisted soda cooking (APSC) was developed to separate cellulose a pulp and lignin from AWW. APSC attained pulp yield of 34.2% at 23% NaOH, showing a 13.2% improvement compared to conventional soda cooking (SC). Fiber length analysis showed APSC-AWW pulp consisted mainly of medium and short fibers, which means blending with long-fibered pulp to enhance the physical strength of pulp sheets. A blend of APSC-AWW pulp and long-fibered pulp in the proportion of 80:20 attained comparable physical strength to hardwood kraft pulp. ASPC-AWW lignin was separated from spent liquor by acidification and then purified by dialysis desalination. The purified ASPC-AWW lignin showed a weight-average molecular weight of 4462 g/mol, similar to softwood kraft lignin but more uniform. Structural analysis revealed that ASPC-AWW lignin was composed of a syringyl unit (S), guaiacyl unit(G), and p-hydroxyphenyl unit (H), and an S unit was dominant with an S/G/H ratio of 74.5:18.2:7.3. It is believed the utilization of fruit tree wood waste as the feedstock of biorefinery is attractive to countries without sufficient forestry resources. Furthermore, the developed APSC is based on conventional SC, which ensures the feasibility of an industrial application. [ABSTRACT FROM AUTHOR]

A practical method for the preparation of lignin derivatives-light-colored bio-based particles (LC-BP) via the modification of hexamethylene diisocyanate (HDI) is presented in this work. In the mixed EtOH/H 2 O system, the change of solvent polarity induced the self-assembly of the lignosulfonate (LS) with the hydrophobic chromophores encapsulated inside the particles. The color of LS was reduced by the polymerization between the isocyanate groups (-N=C=O) of HDI and hydroxy groups of LS. Compared with the typical lignin-based adsorbent preparation process in the past, this is a simple, direct, and efficient preparation method and the synthetic LC-BP has good chemical stability and resistance to heat, acid and alkali. This effectively solves the problem that LS has high water solubility and is difficult to use directly for wastewater treatment. To investigate the properties, the synthetic LC-BP was characterized by SEM, specific surface area, L*a*b* (CIELAB) color space, FT-IR, XPS, and TGA. The results showed that the LC-BP exhibited obvious advantages in color reduction with a low CIE-L* value. The LC-BP exhibits a scale-like intercalation structure, which makes it a promising candidate for adsorbing tetracycline (TC) from wastewater. The conditions of pH, adsorbent dosages, adsorption time, and initial TC concentration were investigated, and the adsorption performance of LC-BP for TC was significantly better than that of conventional polyurethane particles (PP). The adsorption fitted the Langmuir model and there were hydrogen bonding, π-π conjugated binding, and electrostatic attraction during the absorption process. The adsorption capacity was up to 53.1 mg/g, and the removal rate was 67 %. The utilization of LC-BP, a low-cost, effective, and renewable resource derived from natural biomass, holds immense practical and economic potential in wastewater treatment. [Display omitted] • A practical method for the preparation of light-colored lignin • The theoretical basis of lignin-based biomacromolecular compounds was proposed. • Rearrange chromophoric groups of lignin by isocyanate modified • The product can be used as efficient adsorbent for colored wastewater. [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]

[Display omitted] • Flow chemistry using water supports joint valorization of lignin and carbohydrate. • Isolated lignin shows 99.8 % β-O-4 retention and 40.3 % lignin yield. • The extraction liquid contains 80.3 % xylose yield. To achieve the valorization of whole compositions of lignocellulosic biomass, flow fractionation (FF) was developed based on the flow chemistry of the major components of biomass, i.e., glucan, xylan, and lignin. Three kinds of solvent, i.e., water, formic acid, and p -toluenesulfonic acid (p-TsOH), were employed in FF treatments of poplar wood for an evaluation of performance in structure and yield of products. The advantage of FF was firstly confirmed by the nearly complete recovery of glucan in solid product, and the greatly enhanced digestibility of enzymatic hydrolysis as indicated by the glucose yield of 68.1 % at a low cellulase dosage of 10 FPU/g solid product from water treated poplar wood. The second advantage of FF was the rapid hydrolysis and very slight degradation of xylan for the three solvents explored, especially for water as indicated by the xylose yield of 80.3 % from poplar wood treated at 200 °C just for 15 min.. Last but not least, structure-preserved lignins were harvested from biomass with good yield, e.g., 40.3 % of lignin yield and 99.8 % of β-O-4 retention from poplar wood using water as solvent. Thus-obtained lignin (F72T130t30) was successfully transformed to hydrocarbons over Ru/Nb 2 O 5 catalyst with the yield of 21 wt%. In short, these remarkable performances of FF in products structure and yield build a feasible valorization of lignocellulosic biomass for sustainable biorefinery. [ABSTRACT FROM AUTHOR]

• Pith and leaf containing corn stover was fractionated in aqueous formic acid system. • Paper made from fractionation residue showed comparable strength to conventional paper. • Xylose yield reached 11.2 % on the weight basis of untreated rind and pith. • Lignin showed less aliphatic hydroxy groups by 37.9 %–46.6 than conventional technical lignins. Corn stover is collectable byproduct of grain production in agriculture. In this work, pith and leaf containing corn stover was fractionated into cellulose fibers, sugars, and lignin with remarkable yields of 38.9 %, 5.2 % and 25.4 %, respectively by one-step treatment using 85.0 % aqueous formic acid (FA) at conditions of 130 °C for 30 min. Paper sheet was prepared using the obtained cellulose fibers and showed excellent physical strength in terms of tensile index of 50.1 N·m/g, burst index of 3.0 kPa·m2/g and tear index of 6.1 mN·m2/g, comparable to the paper sheet made of conventional alkaline pulp. The obtained sugars contain 61 % of xylose, 17 % of glucose, 15 % of arabinose, 6 % of galactose and 1 % of mannose. The obtained water-insoluble lignin showed less aliphatic hydroxy groups by 37.9 %–46.6% than conventional technical lignins. This property is helpful to the lignin valorization in biodegradable polymer industry as interface-compatible fillers. [ABSTRACT FROM AUTHOR]

A green and efficient flow-through reactor was designed for a robust and cost-competitive biomass fractionation. Aqueous formic acid was used as a solvent at mild temperatures. The established model provided a good description of the delignification process. [Display omitted] • Flow-through formic acid enables fast delignification of wheat straw within 20 min. • The established model provided a good description of the delignification process. • Fractionated lignin shows structural integrity and remarkable yield. • Hemicelluloses were obtained synchronously without degradation. Viable biorefinery requires a robust and cost-competitive method of biomass fractionation. Here, we design green and efficient flow-through reactor for biomass fractionation. Aqueous formic acid was used as a solvent at mild temperatures. The time course study verified a rapid flow-through fractionation of wheat straw in 20 min at 130 °C involving synergetic actions of acid hydrolysis of hemicellulose and lignin dissolution. The obtained fractionation attained 76.3 % of lignin yield and 69.8 % of sugars yield without measurable degradation of hemicelluloses. More importantly, lignin fractionation showed well-preserved inter-unit linkages as indicated by the 76.4 % retention of aryl ether bond. The exponential model was established and well described the relationships between fractionation conditions and kinetics of lignin solubilization. This rapid flow-through reactor/fractionation promises to be a very practical equipment/strategy for biomass fractionation with competitive products. [ABSTRACT FROM AUTHOR]