废茶活性炭的制备及其孔径结构的控制

摘要

Activated carbon was prepared from waste tea by activation with K2CO3 and ZnCl2. The effects of activation temperature,activation time and impregnating ratio on the pore structure of activated carbon were investigated. The activated carbon activated by K2CO3 and ZnCl2 was mainly micro-porous. Waste tea activated carbon obtained by K2CO3 activation had a high surface area of 1388 m2/g,and that obtained by ZnCl2 activation had a high surface area of 1596m2/g. Activation temperature had a significant effect on mesopores of the waste tea activated carbon. Mesopores were formed on the activated carbon by ZnCl2 activation at 350℃. When activation temperature increased from 500℃ to 700℃,mesopore volume decreased from 0.55cm3/g to 0.06cm3/g. Mesopores were formed on the activated carbon obtained by K2CO3 activation when activation temperature was 800℃. Mesopores began to form on the activated carbon activated by ZnCl2 activation at 0.5h. Micropore size of carbon activated by ZnCl2 activation expanded from 0.83nm to 0.87nm when activation time increased from 0.5h to 1.5h,and shrunk at 2h. Mesopores of waste tea carbon activated by K2CO3 began to appear when activation time was up to 2.5h. The largest micropore volume of waste tea activated carbon was obtained when ZnCl2 or K2CO3 impregnation ratio was 1∶1.%利用废茶为原料，分别以K2CO3、ZnCl2为活化剂，在不同的活化温度、活化时间及不同的浸渍比例下制备废茶活性炭。结果表明，K2CO3、ZnCl2活化制备的废茶活性炭孔径结构均以微孔为主，其中K2CO3活化制备的废茶活性炭BET可达1388m2/g，ZnCl2活化制备的废茶活性炭BET可达1596m2/g；活化温度对废茶活性炭的中孔结构影响较大，以 ZnCl2为活化剂时，在温度为350℃时就出现中孔，温度由500℃升至700℃后，中孔容量由0.55cm3/g减小到0.06cm3/g，而以K2CO3为活化剂时，在温度达800℃后才开始出现中孔结构；ZnCl2活化制备的废茶活性炭在活化时间为0.5h时就有中孔出现，当活化时间从0.5h延长至1.5h时，微孔径逐渐由0.83nm增大至0.87nm，当活化时间达到2h后，活性炭结构得到重排，微孔容量提高而中孔容量降低，以K2CO3为活化剂时，活化时间达2.5h后才出现中孔结构；当两种活化剂的浸渍比为1∶1时废茶活性炭的微孔容量最大。