超声波协同作用对纤维素选择性酸水解的影响

摘要

Using acid hydrolysis of cellulose catalyzed by metal ions cooperated with ultrasonic wave,the ultrasonic synergistic role in the promoting selective acid hydrolysis was discussed.The influence on the properties of hydrocellulose from selective acid hydrolysis,as well as acid concentration,the dosage of metal ion,the temperature and duration of acid hydrolysis which were based on the four factors and three levels orthogonal test were investigated.The properties of untreated and treated hydrocellulose were compared by using Laser Particle Size Analyzer,XRD,SEM,FT-IR and TG.The results show that the optimal conditions of ultrasonic synergy for selective acid hydrolysis of cellulose is 2.5 mol/L HCl,0.3 mol/L Fe3+ at 80 ℃ for 50 min,giving rise to the hydrocellulose crystallinity of 79.58% with an increase of 9.89% compared with the untreated hydrocellulose.The average fines length decreases from 47 μm to 29 μm.The crystalline structure and chemical structure of cellulose are not significant changed during the process of ultrasonic synergy.%利用超声波协同金属离子催化纤维素酸水解，探讨了超声波协同对酸水解选择性的促进作用。以酸浓、金属铁离子用量、水解时间和水解温度作为变量，通过四因素三水平正交实验优化实验参数，研究超声协同作用对水解纤维素产品性能的影响。通过激光粒度分析仪、X 射线衍射仪（XRD）、扫描电镜（SEM）、傅里叶红外光谱（FT-IR）和热重分析（TG）对水解纤维素纤维长度、晶型结构、化学组分及形态特征变化进行了表征比较。结果表明：当 Fe3＋浓度为0．3 mol／L，HCl 浓度为2．5 mol／L，温度80℃，反应时间50 min 时，超声协同作用下的水解纤维素结晶度为79．58％，与未处理试样相比增加了9．89％，水解纤维素平均长度由47μm 降为29μm，纤维素化学结构和晶型均未发生改变。