核桃壳真空化学活化制备活性炭

采用真空化学活化法,以核桃壳为原料,氯化锌为活化剂制备活性炭,探讨体系压力、活化温度、浸渍比对活性炭比表面积、孔径分布、碘值和亚甲基蓝值以及表面性质的影响。研究结果表明,30 kPa时制备的活性炭其比表面积和总孔体积比常压条件时分别提高了27%和25%;在低压条件下有利于微孔的形成,在高浸渍比的条件下有利于中孔的形成。在体系压力为30 kPa,活化温度为450℃,浸渍比为2.0时,所得活性炭的BET比表面积为1 800 m2/g,总孔体积为1.176 cm3/g,等电点为9.15,碘吸附量为1 050 mg/g,亚甲基蓝吸附量为315 mg/g。

Preparation of activated carbons from walnut shells by vacuum chemical activation

Activated carbons were prepared from walnut shells by vacuum chemical activation.The effects of system pressure,activation temperature and impregnation ratio on the properties(BET surface area,pore size distribution,iodine and methylene blue adsorption values,and surface characteristics) of activated carbon were studied.The results show that the BET surface area and total pore volume of activated carbon obtained at system pressure of 30 kPa have increased by 27% and 25% respectively compared with those of activated carbon prepared under atmospheric condition.Vacuum condition is beneficial to develop microporous structure,and mesopore tends to be well developed at high impregnation ratio.The activated carbon prepared at system pressure of 30 kPa,activation temperature of 450 ℃,and impregnation ratio of 2.0,possesses a BET surface area of 1 800 m2/g,a total pore volume of 1.176 cm3/g,an iodine adsorption value of 1 050 mg/g,a methylene blue adsorption value of 315 mg/g and an isoelectric point of 9.15.