摘要
利用基于3因素3水平的Box-Behnken设计响应曲面实验,研究了添加干冰为辅助介质的水热预处理条件:预处理温度,预处理时间以及辅助介质添加量这3个因素以及这3个因素中两两交互作用对木质素含量的影响,并对水热预处理条件进行了优化。并采用13C固体核磁波谱(NMR)和红外(FT-IR)光谱分析了木质素的结构变化。根据方差分析,辅助介质添加量对木质素含量的影响最为显著,其次是预处理时间,预处理温度的影响最弱。以木质素含量最小为目标,根据二元回归方程预测出最佳的预处理条件为:温度180℃,时间90 min,0.47 g辅助介质添加量,在最优条件下,木质素含量预计为21.2%,脱除率达到31.6%。固体13C NMR和FTIR分析表明,在水热预处理过程中,木质素的致密结构遭到了破坏,木质素高聚体进行了解聚,产生了单体和低聚体。并且确定玉米芯中的木质素主要是紫丁香基型木质素和愈创木基型木质素。
A response surface methodology based on a three-level, three-variable Box-Behnken design （BBD） was used to analyze the interaction of the hydrothermal pretreatment factors, and optimize the hydrother- mal pretreatment conditions. The structural changes of lignin were analyzed by FTIR and 13C NMR. According to the analysis of the variance, the auxiliary medium dosage was the dominant influencing factor, followed by the pretreatment time, then pretreatment temperature. With a target of minimal lignin content, the optimum pretreat- ment condition predicted by the binary regression equation was 180 ℃ and 90 min, with an auxiliary medium of 0.47 g. Under the optimum conditions, the expected lignin content was 21.2% , and accordingly, the highest lignin removal rate was 31.6%. 13C solid-state NMR spectroscopy and FTIR analysis revealed that the compact structure of lignin was destroyed during the pretreatment, and that the lignin was depolymerized to monomers and oligomers. Moreover. the lignin in corncob mainly consisted of guaiacum and syringe lignin.
出处
《环境工程学报》
CAS
CSCD
北大核心
2016年第9期5210-5216,共7页
Chinese Journal of Environmental Engineering
关键词
水热预处理
干冰
木质素脱除率
木质素结构
响应曲面法
hydrothermal pretreatment
solid CO2
lignin removal rate
structure of lignin
response surface met-hodology
