Mercury Removal from Aqueous Solution Using Coke-Derived Sulfur-Impregnated Activated Carbons

Sulfur-impregnated activated carbons (SIACs) produced from oil-sands fluid coke by KOH-SO2 activation were applied to remove mercury ions from aqueous solutions. A pseudo-first-order rate expression can describe the Hg2+ adsorption behavior of SIACs produced in this study. The rate constants were found to be 0.01-0.102 min(-1). The Hg2+ adsorption capacities of the examined SIACs ranged from 43 to 72 mg/g, which were comparable to those reported in the literature (35-100 mg/g) and that of a commercial SIAC (41 mg/g). The adsorption capacity increased with increasing Specific Surface area (S-BET) of the SIACs, and a positive correlation was found between the S-BET-normalized adsorption capacity and the total sulfur content of the SIACs. Elemental sulfur, disulfide, and thiophene seemed particularly effective in Hg2+ adsorption, as SIACs with these sulfur compounds showed higher adsorption capacities in general.