title: Photocatalytic degradation of phosphamidon on semiconductor oxides.
abstract: The photocatalytic degradation of a small concentration of an organo-phosphorous (OP) insecticide phosphamidon, in water, on ZnO and TiO(2) is investigated. Of the two semiconductor oxides, TiO(2) is found to be more effective as a photocatalyst for this reaction. Several factors such as concentration of phosphamidon, pH of the system, catalyst loading and presence of anions are found to influence the degradation rate. The reaction follows apparent first-order kinetics, though at higher concentrations, there is a reduction in the order of the reaction. There is a simultaneous formation and decomposition of H(2)O(2) in the system, resulting in a periodic increase and decrease in its concentration. The catalyst TiO(2) is effective for the degradation of phosphamidon in direct sunlight and thus opens the possibility of solar decontamination of wastewater containing small amounts of OP pesticides.
authors.affiliation: School of Environmental Studies, Cochin University of Science and Technology, Fine Arts Avenue, 682016, Cochin, India.
authors.forename: Sandhya
authors.initials: S
authors.lastname: Rabindranathan
authors.forename: Suja
authors.initials: S
authors.lastname: Devipriya
authors.forename: Suguna
authors.initials: S
authors.lastname: Yesodharan
mesh_terms: D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry*; D010707:Phosphamidon / Q000737:chemistry*; D010777:Photochemistry; D012666:Semiconductors; D014025:Titanium / Q000737:chemistry; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D015034:Zinc Oxide / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D007306:Insecticides; D010707:Phosphamidon; C009495:titanium dioxide; D014025:Titanium; D015034:Zinc Oxide