木质素基活性炭的制备和吸附特性

Preparation and Adsorption Property of of Activated Carbon from Ligin

用磷酸活化法制备木质素基活性炭,研究了浸渍比、磷酸浓度、活化温度、活化时间对其吸附性能和得率的影响。结果表明,随着浸渍比、磷酸浓度、活化温度、活化时间的增加,活性炭的碘吸附值和亚甲基蓝吸附值均先升后降。适当提高这4个数值有助于木质素形成较多的微孔,提高活性炭的吸附性能;但超过一定程度时,活性炭内部的部分微孔之间的孔壁变薄甚至被烧穿,造成微孔扩大至中孔甚至大孔。同时,磷酸与已生成的微孔结构的孔壁碳原子发生反应,引起炭材料过度烧蚀,使孔径变大,导致活性炭的吸附性能降低。这种活性炭对苯酚的吸附符合Freundlich等温吸附方程,吸附动力学符合Lagergren拟二级速率方程。

Activated carbon from ligin was prepared by phosphate activation in this paper. The effects of 4 factors such as impregnation ratio, phosphate concentration, activation temperature and activation time on the adsorption properties of activated carbons and yield were investigaited. The results show activated carbon iodine adsorption value and methylene blue adsorption value increase at first and then decrease with the increase of impregnation ratio, phosphate concentration, activation temperature and activation time. The four factors contribute to the formation of more micropores, and improve activated carbon adsorption properties. However exceeding a certain level, the internal part of the micropores of the activated carbon between the bore wall thin even burn, resulting in the microporous expanded to the hole and even largeholes. At the same time, phosphate can react with the carbon atoms of a hole wall forming the microporous structure, causing the carbon material excessive ablation, the large pore size, so that the adsorption properties of the activated carbon is reduced. The equilibrium adsorption datum match Freundlich model well. The adsorptions of phenol by activated carbon resin are in accordance with Freundlich isotherm model, and the adsorption kinetics data fit well with the Lagergren pseudo-second order rate equation.