Kinetics and products of the TiO2 photocatalytic degradation of 2-chlorobiphenyl in water.
The light-induced degradation of 2-chlorobiphenyl (2-CB) under simulated solar irradiation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalysts. The apparent quantum yield for an initial 2-CB concentration C0 = 3.8 micrograms/mL at the natural pH was ca. 0.005 The oxidation kinetics of 2-CB follows the Langmuir-Hinshelwood kinetic model at natural pH. The primary degradation of 2-CB follows a pseudo-first-order kinetics. Several reaction intermediates were identified using GC/FTIR/MS and ion chromatography. The products at the initial stage of the reaction were seven isomers of 2-chlorobiphenyl-ol and biphenyl-2-ol. These intermediates underwent further photocatalytic oxidation via aldehydes, ketones, and acids finally into CO2 and HCl. The formation and fate of some of these compounds under irradiation were also investigated. A reaction scheme involving hydroxyl radicals has been proposed.
Hong
C S
CS
Department of Environmental Health and Toxicology, School of Public Health, State University of New York at Albany 12201-0509, USA.
Wang
Y
Y
Bush
B
B
D000327:Adsorption; D001713:Biphenyl Compounds / Q000032:analysis / Q000737:chemistry*; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D017319:Photosensitizing Agents; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D001713:Biphenyl Compounds; D017319:Photosensitizing Agents; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; C055142:2-chlorobiphenyl; D014025:Titanium