title: Arsenite oxidation-enhanced photocatalytic degradation of phenolic pollutants on platinized TiO2.
abstract: The effect of As(III) on the photocatalytic degradation of phenolic pollutants such as 4-chlorophenol (4-CP) and bisphenol A (BPA) in a suspension of platinized TiO2 (Pt/TiO2) was investigated. In the presence of As(III), the photocatalytic degradation of 4-CP and BPA was significantly enhanced, and the simultaneous oxidation of As(III) to As(V) was also achieved. This positive effect of As(III) on the degradation of phenolic pollutants is attributed to the adsorption of As(V) (generated from As(III) oxidation) on the surface of Pt/TiO2, which facilitates the production of free OH radicals ((•)OHf) that are more reactive than surface-bound OH radicals ((•)OHs) toward phenolic pollutants. The generation of (•)OHf was indirectly verified by using coumarin as an OH radical trapper and comparing the yields of coumarin--OH adduct (i.e., 7-hydroxycoumarin) formed in the absence and presence of As(V). In repeated cycles of 4-CP degradation, the degradation efficiency of 4-CP gradually decreased in the absence of As(III), whereas it was mostly maintained in the presence of As(III), which was either initially present or repeatedly injected at the beginning of each cycle. The positive effect of As(III) on 4-CP degradation was observed over a wide range of As(III) concentrations (up to mM levels) with Pt/TiO2. However, a high concentration of As(III) (hundreds of μM) inhibited the degradation of 4-CP with bare TiO2. Therefore, Pt/TiO2 can be proposed as a practical photocatalyst for the simultaneous oxidation of phenolic pollutants and As(III) in industrial wastewaters.
authors.affiliation: Department of Environmental Sciences and Biotechnology, Hallym University , Chuncheon, Gangwon-do 200-702, South Korea.
authors.forename: Jaesung
authors.initials: J
authors.lastname: Kim
authors.forename: Jungwon
authors.initials: J
authors.lastname: Kim
mesh_terms: D000327:Adsorption; D018053:Arsenites / Q000737:chemistry*; D001559:Benzhydryl Compounds / Q000528:radiation effects*; D002384:Catalysis / Q000528:radiation effects; D002733:Chlorophenols / Q000528:radiation effects*; D003374:Coumarins / Q000737:chemistry; D004777:Environment; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D010084:Oxidation-Reduction; D010636:Phenols / Q000528:radiation effects*; D056951:Photoelectron Spectroscopy; D010782:Photolysis; D010984:Platinum / Q000737:chemistry*; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000528:radiation effects*; D000098826:Bisphenol A Compounds
chemical_list: D018053:Arsenites; D001559:Benzhydryl Compounds; D002733:Chlorophenols; D003374:Coumarins; D017665:Hydroxyl Radical; D010636:Phenols; D010984:Platinum; D014025:Titanium; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; C029107:4-chlorophenol; C030123:coumarin; C006780:bisphenol A; D000098826:Bisphenol A Compounds; C015001:arsenite