A green and fast semi-liquefaction strategy: One-step preparation of high-yield nanocellulose particles
Guohua Miao1, Yan Zhou2, Shibo Yang2
1Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China; Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China; Engineering Research Center of Forestry Biomass Materials and Energy, Ministry of Education, Beijing Forestry University, Beijing 100083, China.
Abstract:
The complexity and cost of the biorefinery industry hinder the high-value utilization of lignocellulose. Herein, we propose a green, fast, and economical oxygen-alkali-ethanol (OAE) semi-liquefaction strategy for achieving one-step preparation of hemp stalk material (HSM) biomass into nanocellulose particles (NCPs). Oxygen, alkali, and ethanol have obvious synergistic effects during the semi-liquefaction process, which jointly promote the opening and depolymerization of the crystalline regions of cellulose. The presence of hemicellulose in HSM affects the preparation of NCPs, and the removal of hemicellulose in advance can significantly increase the yield of NCPs. The results showed that the yield of NCPs was as high as 90.14 % with 92.30 % purity after treatment at 120 °C for 2 h. The conversion of rod-shaped nanocellulose to NCPs was successfully captured, and Van der Waals forces were hypothesized to play a dominant role in the formation of NCPs by molecular dynamics simulations. Moreover, the semi-liquefaction can simultaneously fractionate uncondensed lignin with a yield of 46.52 %. With ethanol as a hydrogen donor, the residual lignin was effectively converted to aromatic monomers, predominantly vanillin and syringaldehyde.
