A Novel Recyclable Alkaline Biphasic 2-Phenoxyethanol/Water System for Rice Straw Biorefinery under Mild Conditions
Quan Zhang, Xuesong Tan, Wen Wang, Qiang Yu, Xiaoyan Chen, Changlin Miao, Ying Guo, Yu Zhang, Xinshu Zhuang, Yongming Sun, Xiaoying Kong, Zhenhong Yuan
Abstract
A novel recyclable alkali-assisted biphasic pretreatment process under mild conditions with low water consumption is first developed. After conditions were optimized with the uniform design method, the biphasic 2-phenoxyethanol system presented superior delignification performance with only 6 mL of water consumption per gram of rice straw. Namely, the lignin removal reached 82.16% at 80 °C or 78.15% even at 55 °C. Then, according to the characteristics of the biphasic system, the entire solvent circulation process was constructed. The recycled 2-phenoxyethanol and washing wastewater were directly reused three times at 80 °C, giving more than 80% of lignin removal. Meanwhile, enzymatic digestibility of corresponding residues still exceeded 80% in acetate buffer, or 71% even in black liquor at 72 h. These show the possibility of constructing a biorefinery system based on an alkaline biphasic pretreatment process, with less water and energy consumption, fractionable composition, solvent recyclability, and black liquor utilization.