Dissolution of lignocellulose with high lignin content in AlCl3/ZnCl2 aqueous system and properties of the regenerated cellulose film

Herein, a novel method for dissolving lignocellulose at room temperature is proposed by combining deep eutectic solvents (DES) pretreatment and subsequent dissolution in AlCl3/ZnCl2 aqueous system. Results showed that DES pretreatment could significantly increase the dissolubility of lignin-containing cellulose (CL) samples in AlCl3/ZnCl2 aqueous system. The dissolution ratio of the CL sample with 15.6 % lignin content in AlCl3/ZnCl2·3H2O solvent was as high as 90 %. Besides, the mechanism for the remarkable dissolution of CL samples in low water AlCl3/ZnCl2 aqueous solvent was also proposed. Moreover, the dissolved CL sample was regenerated for the production of lignocellulose films, which have excellent ultraviolet (UV) blocking, hydrophobic, mechanical strength, and natural degradation properties. In particular, the films could be completely naturally degraded after 10 days, which provided a promising way to prepare biodegradable lignocellulose materials, and to encourage the potential utilization of renewable lignocellulose in packaging industry.