title: Photocatalytic degradation of commercial methyl parathion in aqueous suspension containing La-doped TiO2 nanoparticles.
abstract: The photocatalytic degradation of a commercial methyl parathion (MP) under UV irradiation was investigated in aqueous suspension containing lanthanum-doped mesoporous TiO2 nanoparticles (La/m-TiO2) as photocatalyst. The rate of photodecomposition of MP was measured using UV-Vis spectrophotometry, and its mineralization was followed using ion chromatography (IC). The identification of possible intermediate products was carried out using several powerful analytical techniques such as gas chromatography-pulsed flame photometric detector (GC-PFPD) and high performance liquid chromatography-mass spectroscopy (HPLC-MS). Under our conditions, complete disappearance of 20 mg/L of MP occurred within 2 h of illumination, whereas complete mineralization of MP was not achieved through IC analysis. There was a single intermediate product found in the research, which was identified to be methyl paraoxon, owing to the substitution of S by the O atom in the MP molecule. Based on the experimental facts, it is concluded that MP was mainly attacked not by OH radicals but photo-generated holes (h+), resulting from the good adsorption of MP on the catalyst surfaces due to the enhanced adsorption by La doping.
authors.affiliation: College of Science, Huazhong Agricultural University, Wuhan 430070, PR China. hchenhao@mail.hzau.edu.cn
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Min
authors.initials: M
authors.lastname: Shen
authors.forename: Ruiwen
authors.initials: R
authors.lastname: Chen
authors.forename: Ke
authors.initials: K
authors.lastname: Dai
authors.forename: Tianyou
authors.initials: T
authors.lastname: Peng
mesh_terms: D002384:Catalysis; D007811:Lanthanum / Q000737:chemistry* / Q000528:radiation effects; D008743:Methyl Parathion / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects*; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods; D013535:Suspensions / Q000737:chemistry / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods
chemical_list: D013535:Suspensions; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D008743:Methyl Parathion; D007811:Lanthanum; D014025:Titanium