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Conventional methods faced challenges in pretreating natural cellulose fibres due to their high energy consumption and large wastewater drainage. This research devised an efficient solid-state pretreatment method for pretreating hemp fibres using ethanolamine (ETA) assisted by microwave (MW) heating. This method produced a notable removal rate of lignin (85.4 %) with the highest cellulose content (83.0 %) at a high solid content (30 %) and low temperature (70 °C). Both FT-IR and XRD analyses indicated that the pretreatment did not alter the structure of cellulose within the hemp fibres but increased crystallinity as the CrI increased from 84 % in raw hemp fibre to 89 % in pretreated fibre. As a result, it produced hemp fibres with impressive fineness (4.6 dtex) and breaking strength (3.81 cN/dtex), meeting the requirement of textile fibre. In addition, an improvement in glucose concentration (15.6 %) was observed in enzymatic hydrolysis of the MW pretreated hemp fibres compared to the fibres pretreated without MW. Furthermore, the FT-IR and NMR data confirmed that the amination of lignin occurred even at low temperature, which contributed to the high lignin removal rate. Thus, this study presents a potentially effective energy-saving, and environmentally sustainable solid-state method for pretreating hemp fibres., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Degumming is the dominant method to isolate cellulosic fibers in the textile industry. High content of lignin is the principle obstacle in bast-fibers degumming. In order to remove lignin efficiently, the treatment using steam explosion coupled with Fenton oxidation was conducted on kenaf bast in this study. The influence and mechanism of the combined treatment of steam explosion and Fenton oxidation were studied. Fiber microstructure, composition proportion and distribution, cellulose Segal crystallinity and polymerization as well as residual lignin structure were analyzed. The results showed that the pretreatment of steam explosion could sufficiently extract most of the hemicellulose from kenaf bast. Also, the Fenton oxidation followed by alkaline boiling could effectively remove the lignin from the fiber, especially from the fiber surface. The refined dry fibers produced only remained 8.82% of hemicellulose and 9.36% of lignin. And the whole treatment process didn’t change the cellulose crystalline structure but could gradually degrade hemicellulose, lignin and other amorphous gummy matter as well as disordered areas in cellulose, leading to the increase of fiber Segal crystallinity from 62.02 to 70.12%. Part of cellulose was damaged with the increase of degumming intensity, resulting in the decrease of the polymerization degree of cellulose. Meanwhile, the structure of residual lignin changed during the degumming stages of steam explosion, Fenton oxidation and alkaline boiling. All the results revealed that the treatment of combined steam explosion and Fenton oxidation is significantly effectual for isolating bast-fibers. [ABSTRACT FROM AUTHOR]

Kudzu is cosmopolitan and low-cost as a source of fiber, food, medicine, and fuel. However, it is not well utilized as a kind of fiber due to the degumming problem. In order to take full advantage of the kudzu resource in the world and expand the application field of kudzu fiber, this study deals with preparation of kudzu fiber by combined steam explosion and chemical degumming. Kudzu fibers are characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. It is found that kudzu fiber after combined degumming has a clean surface with most nonfibrous composition removed and fibers dispersed; the cellulose I structure of kudzu cellulose did not change after treatment but its crystallinity increased. These results suggest this combined degumming is feasible for preparing kudzu fiber. It will probably provide theoretical basis for subsequent utilization of kudzu fibers. [ABSTRACT FROM PUBLISHER]

The study of the main chemical composition degradation, especially cellulose degradation at high temperatures and within high moisture environments, provides important information that can guide biomass processing using steam explosion (STEX) and other similar treatments. In this paper, kenaf bast was treated using STEX at pressures of 0.5, 1.0, and 1.5 MPa. The chemical composition change and the infrared spectra were investigated. The crystalline index and degree of polymerization of kenaf cellulose were also quantified. It was found that pectin and hemicellulose could be easily degraded with the STEX treatment, while lignin only exhibited slight decomposition; cellulose degraded at 1.5 MPa STEX treatment on the kenaf. Research also indicates that cellulose with a low molecular weight can be removed with a low-pressure STEX treatment. By coupling STEX with chemical degumming process, the high-quality kenaf fiber with 7.12% residue gum content and 134.5 Nm fineness can be obtained. [ABSTRACT FROM AUTHOR]

Abstract: Lotus fiber is a natural cellulose fiber isolated from lotus petiole. Botanically, the fiber is the thickened secondary wall in xylem tracheary elements. In order to obtain essential information for the preparation and processing of lotus fibers, the fine structure and properties of lotus fibers were investigated by the aid of transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), X-ray diffraction (XRD), and so on. The results show that lotus fibers display a rough surface topography and an internal structure different from common plant fibers. The percent crystallinity and preferred orientation of crystallites in lotus fibers are 48% and 84%, respectively. Considering the average breaking tenacity and Young''s modulus, lotus fibers are similar to cotton. The elongation of lotus fibers is only about 2.6% while their moisture regain is as high as 12.3%. [Copyright &y& Elsevier]

Efficient degumming is crucial for valorisation of bast fibres. However, severer conditions and high energy consumption hinder their practical application. This work developed a photocatalytic degumming method assisted by both ZnIn 2 S 4 catalysis and lignin autocatalysis at mild conditions. The method achieved high lignin removal rate (71.6%) and cellulose yield (94.8%) in degumming of hemp fibres, decreasing the major content of β-O-4 bond and β-β bond in lignin from 32.0% to 10.7% and 6.8% to 3.4%, respectively. The pretreated fibres possessed excellent breaking strength (4.46 cN/dtex) and fineness (6.83 dtex). Moreover, the pretreated fibres were readily hydrolysed by cellulase, improving the glucose concentration by 58.3% compared to the alkaline degumming. Furthermore, the synergistic action of ZnIn 2 S 4 and lignin on generation of free radicals was observed. Thus, this work explored the potential of photocatalysis degumming of bast fibres, and discovered the synergistic action of ZnIn 2 S 4 and lignin autocatalysis. [Display omitted] • A mild photocatalytic degumming for fractionation of bast fibres. • High lignin removal (71.6%) at low temperature (30 °C). • The degummed fibers possessed excellent physical and mechanical properties. • Increasing the glucose concentration by 58.3% in enzymatic hydrolysis. • The mechanism of the synergistic action of ZnIn 2 S 4 and lignin was proposed. [ABSTRACT FROM AUTHOR]

Design and synthesis of heterostructured carbon nanofibers is significant for applications in the field of optoelectronics, conductors and catalytic devices. Although lignin has been widely used as building blocks for fabricating nanofibers, it is still very challenging to synthesize conducting heterostructured carbon nanofibers without using additional catalysts. Herein, we first in-situ grew graphene grafted carbon nanofibers (G/CNFs) using calcium lignin sulfonate as starting materials without addition of catalysts. Through the electrospinning, pyrolysis and washing procedure, the as-spun nanofibers are converted into the flexible G/CNFs films. The in-situ formed CaS nanoparticles serve as catalysts for the growth of graphene on the surface of the CNFs, when the carbonization temperature is over 1100 °C. The as-prepared G/CNFs films exhibit superior electronic conductivity of 2377.9 S m−1, which is comparable to the values reported in the literature. As a proof-of-concept, the as-fabricated lithium-sulfur battery exhibits a high discharge of 808.7 mAh·g−1 after 600 cycles at 0.2 C by using the G/CNFs membrane as stand-alone and flexible sulfur cathode scaffolds. This work represents a promising new approach for designing heterostructured graphene/CNFs using low-cost lignin precursors, and provides significant insights for the sustainable development of CNFs in numerous applications. Image 1 • We first demonstrate in-situ grew graphene on carbon fiber without additional catalyst using lignin derived from pulp waste. • CaS nanoparticles on carbon fibers were formed from calcium lignosulfonate, serving as catalysts for the growth of graphene. • Flexible graphene/carbon nanofiber has high electrical conductivity and excellent electrochemical property in Li-S battery. [ABSTRACT FROM AUTHOR]