25 / 2015-11-20 01:42:21

Study on the effect of oxidation-reduction modification on the surface groups and pore structure of activated carbon

spherical activated carbon (SAC);,oxidation-reduction modification; ,surface functional groups; ,pore structure

A series of special activated carbon was prepared by modifying the commercially available spherical activated carbon (SAC) with the method of oxidation and reduction through （NH4）2S2O8, H2O2, heat treatment respectively. SAC before and after modification was characterized by Boehm titration, SEM, N2 adsorption, Roman and DRIFTS methods. Effect of different modification methods on surface functional groups and pore structure of activated carbon were investigated. With concentrations of （NH4）2S2O8 increasing, the content of carboxylic acid and acidic functional groups of activated carbon increased, while basic groups content decreasing. SAC-20%H2O2 had the highest acidic functional groups content almost 3 times greater than SAC. The results showed that acidic functional groups content particularly the content of carboxylic acid had greatly increased while basic groups content was virtually none during oxidation modification. In contrast, total surface functional groups content declined and basic groups content increased as the modified temperature increases during reduction modification. Besides, the specific surface area and pore size had changed more or less before and after modification, which were scarcely affected at SAC-900 during reduction modification. The latter could give some support on the correlation study between the different surface functional groups and its gas selective absorption under the conditions of the same or similar pore structure, and thus has a great potential of real-world applications.