TY - JOUR
T1 - Photocatalytic degradation of acephate in pak choi, Brassica chinensis, with Ce-doped TiO2
AU - Liu, Xiangying
AU - Wang, Lifeng
AU - Zhou, Xiaomao
AU - Liu, Kailin
AU - Bai, Lianyang
AU - Zhou, Xuguo
N1 - Publisher Copyright:
© 2015, Copyright © Taylor & Francis Group, LLC.
PY - 2015/5/4
Y1 - 2015/5/4
N2 - The photocatalytic degradation of acephate was investigated using Ce-doped TiO2 (TiO2/Ce) hydrosol. In contrast to previous research conducted under artificial light in the laboratory, this study investigated the decomposition of acephate in a field trial. The results show that acephate can be efficiently degraded by the TiO2/Ce system under natural field conditions; the degradation efficiency was affected by the dosage of the photocatalyst and acephate. The optimum dosage of TiO2/Ce was 2400 g a.i.ha−1, and the photodegradation efficiency of acephate reached 93.5% after 20 h at an acephate dosage of 675 g a.i.ha−1. Ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) analysis detected and identified four degradation products—methamidophos, phosphorothioic acid O,O,S-trimethyl ester, S-methyl methanethiosulfonate and phosphorous acid—that were formed during the TiO2/Ce photodegradation of acephate. Based on the structural identification of the degradation products, a probable photodegradation pathway was proposed, and the first decomposition step may be the cleavage of the C‒N bond of acephate. Subsequently, the P‒S and P‒O bonds may be oxidized gradually or simultaneously to complete the mineralization.
AB - The photocatalytic degradation of acephate was investigated using Ce-doped TiO2 (TiO2/Ce) hydrosol. In contrast to previous research conducted under artificial light in the laboratory, this study investigated the decomposition of acephate in a field trial. The results show that acephate can be efficiently degraded by the TiO2/Ce system under natural field conditions; the degradation efficiency was affected by the dosage of the photocatalyst and acephate. The optimum dosage of TiO2/Ce was 2400 g a.i.ha−1, and the photodegradation efficiency of acephate reached 93.5% after 20 h at an acephate dosage of 675 g a.i.ha−1. Ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) analysis detected and identified four degradation products—methamidophos, phosphorothioic acid O,O,S-trimethyl ester, S-methyl methanethiosulfonate and phosphorous acid—that were formed during the TiO2/Ce photodegradation of acephate. Based on the structural identification of the degradation products, a probable photodegradation pathway was proposed, and the first decomposition step may be the cleavage of the C‒N bond of acephate. Subsequently, the P‒S and P‒O bonds may be oxidized gradually or simultaneously to complete the mineralization.
KW - Acephate
KW - TiO/Ce
KW - field trial
KW - photocatalysis
UR - http://www.scopus.com/inward/record.url?scp=84926361740&partnerID=8YFLogxK
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U2 - 10.1080/03601234.2015.1000177
DO - 10.1080/03601234.2015.1000177
M3 - Article
C2 - 25826101
AN - SCOPUS:84926361740
SN - 0360-1234
VL - 50
SP - 331
EP - 337
JO - Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes
JF - Journal of Environmental Science and Health - Part B Pesticides, Food Contaminants, and Agricultural Wastes
IS - 5
ER -