Preparation of activated carbon from needle coke via two-stage steam activation process

Abstract Mesoporous activated carbon was prepared from needle coke via two-stage steam activation process under high temperature. Two-stage steam activation method involves three main steps: 1st steam activation to generate mesopores and macropores above 2 nm; coating and impregnation of substances with a low molecular weight into the pores; 2nd steam activation to expand the pore size and micropore volume. The needle coke was characterized by elemental analysis, polarized light microscopy, and thermogravimetric analysis, and the porosity structure was analyzed by the Brunauer-Emmett-Teller (BET) method, the t-plot method, the Barrett-Joyner-Halenda (BJH) method, and the scanning electron microscopy (SEM). The maximum specific surface area and mesopore volume ratio of activated carbon manufactured by two-stage steam activation method was 1134 m2/g and 78%, respectively. The mesopore volume and average pore diameter increased as more coating and impregnation agents were added.