Adsorption/oxidation of CH3SH on activated carbons containing nitrogen

Activated carbons of different origins were impregnated with urea and heat-treated at 450 and 950 degreesC. Surface properties of adsorbents were evaluated using nitrogen adsorption, potentiometric titration, Boehm titration, elemental analysis, and thermal analysis. Then, the CH3SH breakthrough capacity tests were carried out and the adsorption capacities were evaluated. The results showed that the amount adsorbed depends strongly on the modification conditions of the carbon surface. It increased from 1.4 to 10 times after introduction of nitrogen species. Immobilization of methyl mercaptan on the surface is likely governed by the redox process, and basic nitrogen groups can act as catalysts for electron transfer from sulfur to oxygen. Dimethyl disulfide and methyl methanethiosulfonate are the main products of methyl mercaptan oxidation.