Study of the decomposition and detoxification of the herbicide bentazon by heterogeneous photocatalysis: Kinetics, intermediates and transformation pathways
Study of the decomposition and detoxification of the herbicide bentazon by heterogeneous photocatalysis: Kinetics, intermediates and transformation pathways
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DOI：
10.1016/j.apcatb.2016.06.068
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发表时间：
2017-01-01
影响因子：
22.1
通讯作者：
Poulios, Ioannis
中科院分区：
文献类型：
--
作者：
Berberidou, Chrysanthi;Kitsiou, Vasiliki;Poulios, Ioannis
研究了除草剂苯达松在水溶液中的光催化降解和矿化作用。研究了不同光催化剂种类、催化剂负载量、初始pH值和电子受体添加量等条件下的准一级降解动力学。降解率被证明是强烈的影响，这些参数。在TiO 2 P25或TiO 2 Kronos vlp 7000和UV-A的存在下，有机硫和氮仅部分转化为无机硫和氮。H2 O2的存在下导致增强或降低的初始降解速率，这取决于所采用的催化剂的类型。通过高分辨率LIT Orbitrap LC-ESI/MS系统鉴定了光催化处理过程中形成的中间产物。共鉴定出21种中间体，包括苯达松二聚体、羟基和酮基衍生物以及进一步氧化的产物，并提出了详细的转化途径。使用海洋细菌费氏弧菌的急性毒性概况在氧化的第一阶段显示出增加的趋势，这意味着逐步形成比母体分子更具毒性的中间体，或转化产物之间的协同效应。此后，生态毒性被完全消除90分钟内的照射下的调查条件。植物毒性试验，进行了单子叶植物山梨糖和双子叶植物白芥子和独行菜，表现出类似的反应的三种植物物种的光催化处理的样品，导致完全去除植物毒性的条件下。(C)© 2016 Elsevier B. V.版权所有。
Photocatalytic degradation and mineralization of the herbicide bentazon in aqueous solutions has been investigated. The pseudo-first order degradation kinetics was studied under different operational conditions, such as type of photocatalyst, catalyst loading, initial pH and addition of electron acceptors. The degradation rates proved to be strongly influenced by these parameters. Organic sulfur and nitrogen were only partially converted into inorganic in the presence of TiO2 P25 or TiO2 Kronos vlp 7000 and UV-A. The presence of H2O2 led to either enhancement or decrease of the initial degradation rates, depending on the type of catalyst employed. Intermediate products formed during photocatalytic treatment were identified by means of a high resolution LIT Orbitrap LC-ESI/MS system. 21 intermediates including dimers, hydroxy and/or keto bentazon derivatives, and further oxidized species were identified and detailed transformation pathways have been proposed. Acute toxicity profiles using marine bacteria Vibrio fischeri showed an increasing trend at the first stages of oxidation, implying the progressive formation of intermediates more toxic than the parent molecule, or synergistic effects among the transformation products. Thereafter, ecotoxicity was completely eliminated within 90 min of irradiation under the investigated conditions. Phytotoxicity tests, carried out on the monocotyl Sorghum saccharatum and the dicotyls Sinapis alba and Lepidium sativum, showed similar responses of the three plant species to the photocatalytically treated samples, resulting to complete removal of phytotoxicity under the employed conditions. (C) 2016 Elsevier B.V. All rights reserved.