title: Photocatalytic degradation and mineralization of commercial methamidophos in aqueous titania suspension.
abstract: The photocatalytic degradation of a commercial methamidophos (MAP) emulsion in aqueous suspension containing mesoporous titania (m-TiO2) nanoparticles under UV irradiation was investigated. The mineralization rate of MAP went up steadily as prolonging the irradiation time and reached ca. 95% after 4 h irradiation based on determination of the end-products (NO3-, PO4(3-), and SO4(2-)) of MAP through IC analysis. Moreover, the degradation kinetics of MAP followed the first-order reaction and has been monitored through GC-PFPD analysis, which also showed that MAP and the organic solvent as well as additive in the pesticide emulsion can be degraded readily and simultaneously. Photodegradation intermediates derived from two different concentrations of MAP were detected by GC-MS technique. The experimental facts indicated that the photodegradation mechanism of MAP mainly involves electron transfer process and hydroxylation process, and the dominant mechanism for MAP degradation in the initial steps can be attributed to the electron transfer process, which resulted in the formation of all intermediates containing P species detected in the initial photodegradation stage.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Dai
authors.forename: Tianyou
authors.initials: T
authors.lastname: Peng
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Ruixue
authors.initials: R
authors.lastname: Zhang
authors.forename: Youxiang
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D002384:Catalysis; D008903:Minerals / Q000737:chemistry*; D009946:Organothiophosphorus Compounds / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry*; D010777:Photochemistry; D012996:Solutions; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D008903:Minerals; D009946:Organothiophosphorus Compounds; D010575:Pesticides; D012996:Solutions; D014867:Water; C014655:methamidophos; D014025:Titanium