KOH活化法优化制备辣椒秸秆基活性炭及其性能表征

Optimization of preparation of pepper straw based activated carbon by KOH activation method and its performance characterization

以辣椒秸秆为原料、KOH为活化剂制备生物质活性炭。采用单因素分析与正交试验设计,以炭得率、亚甲基蓝吸附量、碘吸附值为评价指标,考察活化温度、活化时间、浸渍比、浸渍时间对制备活性炭性能的影响,优化得到最佳制备条件,并利用扫描电镜、比表面积及孔径分析仪、红外光谱仪等技术手段对样品的性能进行表征分析。结果表明:辣椒秸秆基生物质活性炭的最佳制备条件为活化温度800℃、活化时间150 min、浸渍比2∶1、浸渍时间24 h,该条件下所制活性炭的炭得率为72.29%,亚甲基蓝吸附量为19.42 mg/g,碘吸附值为1042.16mg/g;其比表面积为1077.57 m^(2)/g,平均孔径为3.01 nm,属于中孔型活性炭,同时存在微孔和少量大孔结构;其表面存在胺基、醚基、酚、醇羟基、羰基等含氧官能团,吸附性能良好。

Biomass activated carbon was prepared with pepper straw as raw material and KOH as activator.Single factor analysis and orthogonal experimental design were used to investigate the effects of activation temperature,activation time,impregnation ratio and impregnation time on the performance of activated carbon with carbon yield,methylene blue adsorption capacity and iodine adsorption value as evaluation indexes,and the optimal preparation conditions were obtained by optimization.The properties of the samples were characterized and analyzed by scanning electron microscope,specific surface area and pore size analyzer,infrared spectrometer and other technical means.The results showed that the optimum preparation conditions of pepper straw based biomass activated carbon were activation temperature 800℃,activation time 150 min,impregnation ratio 2∶1 and impregnation time 24h.Under these conditions,the carbon yield of the prepared activated carbon was 72.29%,the adsorption capacity of methylene blue was 19.42 mg/g and the adsorption value of iodine was 1042.16 mg/g;Its specific surface area is 1077.57m ^(2)/g and the average pore diameter is 3.01nm.It belongs to mesoporous activated carbon,and there are micropores and a small amount of macropores at the same time;Its surface has oxygen-containing functional groups such as amine group,ether group,phenol,alcohol hydroxyl group and carbonyl group,and its adsorption performance is good.