Ning Ding,Xiaoqiang Song,Yetao Jiang,Bin Luo,Xianhai Zeng,Yong Sun,Xing Tang,Tingzhou Lei,Lu Lin
Cooking with active oxygen and solid alkali (CAOSA), developed by our group, is a promising alternative to both clean pulping and biomass pretreatment since it is a facile technique with advantages of environmental benignity and easy alkali recovery. Through comparative analysis using 2D-HSQC NMR, the superior delignification efficiency of the CAOSA process could be attributed to the more efficient cleavage of the benzene ring in lignin, which is in sharp contrast to the conventional pulping route. Abundant organic acids were detected in the product solution, which is also known as yellow liquor (YL). In addition, acid insoluble degradation products (AIDPs) containing aromatic compounds were present in the YL, which were separated and collected. The low AIDP content in the YL suggested the highly efficient decomposition of the aromatic rings. This delignification study not only presents a deeper investigation of the CAOSA process itself but also provides guidance for further research on biomass-lignin degradation.
Jiang Yetao,Wang Xiaoyu,Wu Zhen,Xu Jiaxing,Hu Lei,Lin Lu
Cooking with active oxygen and solid alkali (CAOSA) is a mild and environmentally friendly method for separation of lignin components. The degradation mechanism of hemicellulose associated with this method has been investigated. It was found that the hemicellulose-derived polysaccharides were directly oxidized rather than hydrolyzed to monosaccharides for degradation. To avoid the undesirable degradation of hemicellulose components by CAOSA, the idea of separating hemicellulose first in the form of xylan to produce xylooligosaccharide was presented by this study. Although hydrothermal autocatalysis has been commonly used in hemicellulose separation, the effects of acid-enhanced hydrothermal method and alkali-suppressed hydrothermal method on hydrothermal autocatalysis were systematically compared for the first time, and it was found that the acid-enhanced method was beneficial for highly selective extraction of xylan. Then, the hemicellulose-removed bamboo was treated with CAOSA process to separate lignin from cellulose. It was found that solid alkali dosage of CAOSA could be evidently decreased for hemicellulose-removed bamboo, which was helpful to reduce the cost of CAOSA. Coupling hemicellulose pre-extraction and CAOSA lignin fractionation strategy, a comprehensive biorefinery case for bamboo biomass could be anticipated.
危险品化学品经营许可证（带存储）