Study on Activated Carbon Prepared from Coking Fly Ash with KOH Activation

Abstract

An orthogonal experiment is conducted to study the effect of activation temperature, activation time and the ratio of KOH to carbon material (i.e. the mass ratio of KOH to coking fly ash) on the adsorption capacities of the activated carbon made by using coking fly ash as the raw material and KOH the activating agent. The results show that the three factors can be ordered as activation temperature, activation time and the ratio of KOH to carbon material according to the significance in their effect on preparation of activated carbon from coking fly ash. In addition, the optimum activation temperature is 850°C, optimum activation time 30minutes, and the optimum ratio of KOH to carbon material 4:1. For the activated carbon made under these conditions, the iodine absorption capacity is 874.3774mg/g, specific surface-area 275.51m2/g, the mean pore diameter 47.75nm and total pore volume 0.1172cm3/g. As the proportion of mesoporouses reaches 71.57%, the activated carbon made from coking fly ash is good for absorption of those absorbates with higher molecular weights.