A systematic study of lignocellulose nanofibrils (LCNF) prepared from wheat straw by varied acid pretreatments

Abstract

Due to the complex and recalcitrant structure of the cell wall, the current process of lignocellulose nanofibrils (LCNF) preparation directly from lignocellulosic biomass presents environmental pollution, large consumption of energy and chemicals, and low economic efficiency. In the previous research, we successfully prepared LCNF from wheat straw. However, the mechanism of different acids with small quantities in the pretreatment of lignocellulose during the preparation of LCNF is unrevealed. Herein, we select six organic and inorganic acids to pretreat wheat straw combined with glycerol swelling and mechanical action to directly prepare LCNF from wheat straw. The chemical, physical, mechanical, and thermal performances of LCNF are systematically investigated. Furthermore, the acidity of different reaction systems (glycerol and glycerol mixture containing varied acids) is evaluated to reveal the potential relationship between the performance of LCNF and varied acids with small quantities. The obtained H2SO4-LCNF film possesses good mechanical performances (the specific tensile stress of 78.4 KN m/kg and specific Young's modulus of 6.0 MN m/kg). Overall, we hope this work could offer theoretical guidance for the large-scale production of LCNF directly from lignocellulosic biomass by varied acid pretreatments.