title: Novel photo-sulfite system: toward simultaneous transformations of inorganic and organic pollutants.
abstract: An efficient and green advanced oxidation process (i.e., photo-sulfite reaction) for the simultaneous oxidation of sulfite and organic pollutants in water is reported. The photo-sulfite system (UV-Fe(III)-sulfite) is based on the Fe-catalyzed sulfite oxidation and photochemistry of Fe(III) species. SO4(•-) and (•)OH radicals were identified in the photo-sulfite system with radical scavenging experiments using specific alcohols. This novel technology was consistently proven to be more favorable than the alternative Fe(III)-sulfite systems for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) and other organic pollutants at all conditions tested. The reactivity of photo-sulfite system was sustained due to the spontaneous switch of photoactive species from Fe(III)-sulfito to Fe(III)-hydroxo complexes with the depletion of sulfite and the decrease in pH. In contrast, in the absence of light the performance of the Fe(III)-sulfite system was greatly diminished after the consumption of sulfite. The formation of the Fe(III)-sulfito complex is a necessary step for initiating the photo-sulfite reaction. Inhibition of the oxidation of 2,4,6-TCP and methyl orange (MO) was observed in the presence of ligands that can stabilize one or more of the reactants: Fe(III), Fe(II), or sulfite. Our study provides a new facile route for the generation of SO4(•-) and simultaneous removal of organic and inorganic pollutants.
authors.affiliation: State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University , Shanghai, 201620, China.
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiaoyi
authors.initials: X
authors.lastname: Lou
authors.forename: Changling
authors.initials: C
authors.lastname: Fang
authors.forename: Dongxue
authors.initials: D
authors.lastname: Xiao
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wang
authors.forename: Jianshe
authors.initials: J
authors.lastname: Liu
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D001557:Benzenesulfonates / Q000737:chemistry; D002733:Chlorophenols / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008751:Methylene Blue / Q000737:chemistry; D012235:Rhodamines / Q000737:chemistry; D013447:Sulfites / Q000737:chemistry*; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D002733:Chlorophenols; D004396:Coloring Agents; D012235:Rhodamines; D013447:Sulfites; D014874:Water Pollutants, Chemical; C100258:methyl orange; D007501:Iron; C029773:rhodamine B; C024564:2,4,6-trichlorophenol; C014722:2-naphthol orange; D008751:Methylene Blue