Surface Properties of Modified Activated Carbon for Ammonia Gas Removal

This research assessed the surface properties of modified activated carbons with three different acids and five different metals for ammonia gas removal. Raw bituminous coal-based activated carbon ( $4{\times}8$ mesh) had low adsorption capacity of 0.72 mg $NH_3/g$ based on the analysis in the column adsorption experiment. Adsorption capacities of carbons modified with $CH_3COOH$ , $H_3PO_4$ , and $H_2SO_4$ increased up to 3.34, 21.00, and 35.21 mg $NH_3/g$ , respectively. Those of carbons with Cu, Zn, Zr, Fe, and Sn were 9.63, 9.13, 7.09, 25.12 and 15.03 mg $NH_3/g$ . Ammonia adsorption was enhanced by the presence of surface oxygen groups on carbon materials, which influenced pH of carbon surface. BET surface area of raw carbon was analyzed to be $1087m^2/g$ , but it decreased by carbon surface modification. Fe-impregnated carbon showed $503.02m^2/g$ of surface area. These observations were mostly caused by chemical adsorption.