Degradation of 2, 4, 6-trichlorophenol in Photo-sulfite System: Mineralization and Pathways

Photo-sulfite reaction is a novel efficient advanced oxidation process for degradation of 2,4,6- trichlorophenol (2,4,6-TCP). In the present work, degradation intermediates and mineralization of 2,4,6-TCP in the photo-sulfite system were examined and the degradation pathways were proposed. Several dechlorinated compounds were identified, as well as some non-chlorinated low molecular weight carboxylic acids. However, the more toxic polychlorophenols and dibenzofuran were also unexpectedly detected, which were thought to decrease the extent of mineralization. The proposed degradation mechanism of 2,4,6-TCP in the photo-sulfite system indicated both de novo formation of polychlorophenols involving the released chlorine atom/chloride ion, and formation of dibenzofuran involving phenol oxidation. The present study might have implications in detoxification of chlorinated organic contaminants by the novel photo-sulfite process.