响应面法优化设计木质素基活性炭的制备

Optimization of Design of Lignin-based Activated Carbon Based on Response Surface Methodology

以玉米芯木质素为原料,采用磷酸活化法制备木质素基活性炭;并以亚甲基蓝吸附值为考察指标,通过Plackett-Burman设计、最陡爬坡实验和中心复合设计方法,探究了不同工艺条件在活性炭制备过程中的交互作用及最优工艺参数。结果发现:Plackett-Burman设计筛选得到的3个最重要因素分别为浸渍比、活化温度和活化时间;通过最陡爬坡实验确定了其最佳中心点区域;中心复合设计(CCD)和响应面分析(RSM)得到的最佳工艺条件为浸渍比3∶1(g∶g)、活化温度563℃和活化时间2.75 h。通过验证实验表明:在上述优化工艺及磷酸质量分数60%、浸渍时间12 h、浸渍温度90℃条件下,木质素基活性炭的孔径主要集中在2~10 nm,BET比表面积为1436 m2/g,总孔容为1.041 cm3/g,微孔孔容为0.3856 cm3/g,亚甲基蓝吸附值为240 mg/g。

Lignin-based activated carbon was prepared from corn cob lignin by using phosphoric acid activation method.Taking methylene blue adsorption value(MB)as the index,the interaction during the preparation of activated carbon were explored by Plackett-Burman design,the steepest climbing test,and the center composite design method.The results showed that the three most important factors obtained by Plackett-Burman design were immersion ratio,activation temperature,and activation time.The best center region was determined through the steepest climbing test.The optimal process conditions obtained by the center composite design(CCD)and response surface analysis(RSM)were impregnation ratio 3∶1(g∶g),activation temperature 563℃,and activation time 2.75 h.The verification experiment was performed under the above optimized process of 60%phosphoric acid mass fraction,12 h immersion time,90℃immersion temperature.The pore size of the lignin-based activated carbon was mainly concentrated at 2-10 nm,the BET specific surface area was 1436 m2/g,total pore volume was 1.041 cm3/g,the micropore pore volume was 0.3856 cm3/g and the methylene blue adsorption value(MB)was 240 mg/g.