Abstract: The Photocatalytic degradation reaction of 2-chloroethyl ethyl sulfide (2-CEES) on P25 TiO2 was studied by using flow micro-reaction technique, GC-MS, and in situ FTIR. It was showed that 2-CEES could be oxidized finally into CO2 and H2O at room temperature during the process. Detailed analysis found that C2H4, CH3CHO, CH4, CO, HCl and H2S; a small quantity of low molecular weight carboxylic acids, ethers and sulphones; a trace amount of C2H5SC2H5, C2H5S2C2H5, C2H5SC2H4Cl and CH2ClCH2Cl exist in the gaseous product of reaction besides CO2 and H2O, and some species such as C2H5S2C2H5, C2H5SC2H4OH, C4H9S2C2H5, C2H5S2C2H4OH and SO42- remain on the surface of the catalyst after reaction. According to the above results, a photocatalytic degradation mechanism of 2-CEES was suggested, deducing that 2-CEES was photocatalytically degraded into CO2 and H2O via a complicated process including dechlorination, C－S bond splitting, photo-polymerization and decompose of organo-sulfur intermediates. The accumulation of sulfur-contained species on the surface was thought to result in deactivation of the catalyst.

Key words: 2-chloroethyl ehtyl sulfide(2-CEES), Photocatalytic degradation, 　Reaction mechanism, Disinfection