Selective Removal of Methyl Mercaptan Using Silver-loaded Carbon Nitride Photocatalyst

Abstract

In general, air pollutants such as volatile organic compounds (VOCs) are not degraded by the CN based catalysts generating O2- radicals, but only by WO3 based catalysts generating OH radicals. In this study, we found that CN based catalysts can selectively degrade methyl mercaptan, which is a typical odorous compound, under visible light. Modification of carbon nitride with silver nanoparticles significantly enhanced the adsorption capacity for CH3SH using interaction between Ag and sulfur atoms. Additionally, deposited Ag nanoparticles as co-catalyst increased the photoconversion efficiency and production of reactive radical species. On the basis of the control test of oxygen and water in the carrier gas and EPR analysis, it was revealed that the responsible reactive species for CH3SH decomposition was O2- radical. Mass balance of removed sulfur atoms and FT-IR analysis showed that Ag/CN degraded methyl mercaptan to gaseous dimethyl disulfide (CH3SSCH3) and sulfate deposited on the surface of catalyst. Thus, Ag/CN is proposed as an effective and appropriate photocatalyst to remove CH3SH under visible light.