响应面试验优化微波-超声协同辅助硫酸降解玉米秸秆工艺

研究微波、超声与微波-超声3种辅助硫酸降解玉米秸秆方法,并采用响应面法对微波-超声协同辅助硫酸降解玉米秸秆的工艺进行优化,建立还原糖得率的五元二次回归数学模型,并进行了模型的有效性分析、单因素效应分析、边际效应分析及因素间的交互作用分析。最佳工艺条件为温度82℃、时间153 min、硫酸体积分数3.1%、料液比1∶45(g/m L)和微波功率634 W,在此条件下,还原糖得率最大值为41.24%,实际结果与模型预测值吻合度高,说明该模型切实可行。与在温度120℃、硫酸体积分数3%、料液比1∶20(g/m L)、时间2 h条件下水解玉米秸秆还原糖得率相比,含量提高6.6%。并通过离子色谱分析得出阿拉伯糖含量为1.75%,半乳糖含量为0.44%,葡萄糖含量为15.65%,木糖含量为7.98%,果糖含量为15.34%,纤维二糖含量为0.09%。

Optimization of Microwave/Ultrasonic-Assisted Sulfuric Acid Hydrolysis of Corn Straw by Using Response Surface Methodology

In this study, we evaluated and compared the effectiveness of single and combined applications of microwave
and ultrasonic for enhancing the sulfuric acid hydrolysis of corn straw. It turned out that the combined use of microwave and
microwave was superior to either alone. Further, we optimized the microwave/ultrasonic hydrolysis process by using onefactor-
a-time method and response surface methodology. A quadratic regression model for predicting the yield of reducing
sugar as a function of 5 independent variables was formulated and validated. The marginal effect of the independent variables
studied and their interactions were tested. The optimal process conditions were obtained as follows: temperature, 82 ℃;
reaction time, 153 min; sulfuric acid concentration, 3.1%; solid/liquid ratio, 1:45 (g/mL); and microwave power, 634 W.
Under these conditions, the maximum yield of reducing sugar of 41.24% was obtained experimentally, which was in good
agreement with the model prediction, indicating that the model is feasible. A 6.6% increase was achieved as compared to that
obtained under the conditions: reaction time for 2 h at 120 ℃, a sulfuric acid concentration of 3%, and a solid/liquid ratio of
1:20 (g/mL). Ion chromatographic analysis revealed that the hydrolysate solution under the optimized conditions contained
1.75% arab sugar, 0.44% galactose, 15.65% glucose, 7.98% xylose, 15.34% fructose, and 0.09% cellobiose.