Surface properties of activated carbon from different raw materials

Activated carbons (ACs) with different surface properties were prepared from different raw materials. N₂ adsorption, pH value, Boehm titration, Temperature-programmed reduction (TPR) and FTIR were employed to characterize the pore structure and surface chemical properties of the ACs. The results show that AC from bituminous coal (AC-B) has more meso-pores, higher pH value, more carboxylic groups and basic site than ACs from coconut shell and hawthorn(AC-C, AC-H). Oxygen in the mixture gas has great effect on SO₂ catalytic oxidation/oxidation ability of AC-B. In the absence of oxygen, the adsorbed SO₂ on AC-B is 0.16 mmol/g and the conversion ratio of adsorbed SO₂ to SO₃ is 22.07%; while in the presence of oxygen, the adsorbed amount of SO₂ is 0.42 mmol/g, and all of the adsorbed SO₂ was totally converted to SO₃. This feature of AC-B is consistent with its higher pH value, basic site and the reaction ability with H₂ from TPR. The conversion ratios of SO₂ absorbed on both AC-C and AC-H were 100%, respectively.