Characteristic comparison of lignocellulose nanofibrils from wheat straw having different mechanical pretreatments

Abstract

Wheat straw (WS) was considered the most abundant agricultural residue in China. Therefore, it was meaningful to explore the effective utilization of WS. Thus far, WS has been considered a potential raw material to produce lignocellulose nanofibrils (LCNFs) with the rapid development of nanotechnology. Unfortunately, the existing methods of LCNFs preparation directly from WS still faced some hurdles. Herein, screw extrusion and ball milling considered the common mechanical pretreatments were employed to directly prepare LCNFs from WS. The different impacts of screw extrusion and ball milling pretreatments on the properties of LCNFs were revealed by systematically comparing physicochemical analyses. The results showed that the crystalline and chemical structure of samples was little affected by the mechanical pretreatment. However, the mechanical pretreatment caused a change in the morphology, yield, and chemical composition of LCNFs. LCNFs prepared by screw extrusion with a high yield of 73% had the narrowest diameter distribution (0 ~ 80 nm), the most cellulose content (51.1%), and the maximum crystallinity degree (44.7%). LCNF samples all exhibited good thermal stability. This work could not only offer theoretical guidance on the preparation of LCNFs by mechanical pretreatments but also expand the high‐value application of WS in polymer composites.

Recent Advances in Application of Polyoxometalates in Lignocellulose Pretreatment and Transformation

“…Lignocellulose is considered a promising feedstock for the production of biofuels, which are comparatively better and economical than other fuels [ 14 , 15 ], and they can be converted into platform chemicals [ 16 , 17 ], biopolymer [ 18 , 19 ], cosmetics [ 20 ], food additives [ 21 ], and other value-added products due to its abundance, renewability, and low cost [ 22 , 23 ]. It has been proved that the cellulose fibers are covered with hemicellulose, whereas lignin fills the spaces between the cellulose fibers [ 24 , 25 ]. However, many natural factors defined as biomass recalcitrance hinder the effective conversion of biomass, for instance, complex cell wall constituents, degree of lignification, cellulose crystallinity, and structural heterogeneity [ 26 ].…”