Photodegradation of atrazine in the presence of indole-3-acetic acid and natural montmorillonite clay minerals
Photodegradation of atrazine in the presence of indole-3-acetic acid and natural montmorillonite clay minerals
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吲哚-3-乙酸和天然蒙脱石粘土矿物存在下莠去津的光降解
DOI：
10.1016/j.envpol.2018.05.002
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发表时间：
2018
影响因子：
8.9
通讯作者：
Gu Cheng
中科院分区：
文献类型：
--
作者：
Zhang Lin;Tian Haoting;Hong Ran;Wang Chao;Wang Yi;Peng Anping;Gu Cheng
阿特拉津（2-氯-4-乙基氨基-6-异丙基氨基-s-三嗪）是一种常用的农业除草剂，因此经常在地表水和地下水中检测到。在这项研究中，我们提供了在环境相关条件下，特别是在天然蒙脱土和普遍存在的植物激素吲哚-3-乙酸（IAA）存在的情况下，阿特拉津的光氧化的证据。该反应是由IAA的光电离产生水合电子引起的。这些电子与质子和溶解氧反应形成羟基自由基，促进阿特拉津的进一步降解。蒙脱土通过嵌入在粘土中的负电荷的静电吸引来稳定自由基阳离子，从而强有力地提高了水合电子的产率并延长了它们的寿命。此外，蒙脱土提供了一个密闭的空间，显著增加了阿特拉津与活性自由基接触的可能性。其他影响降解过程的因素包括溶液pH值、粘土夹层中存在的交换阳离子类型以及蒙脱土的水化状态。由于IAA和蒙脱土在环境中广泛分布，预计该反应将在降解阿特拉津和其他潜在的持久性有机污染物中发挥重要作用。
Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) is a commonly used agricultural herbicide that, as a result, is frequently detected in surface and ground water. In this study, we provide evidence of the photo-oxidation of atrazine under environmentally relevant conditions, specifically, in the presence of natural montmorillonite clay and the ubiquitous phytohormone indole-3-acetic acid (IAA). The reaction is initiated by the generation of hydrated electrons from the photo-ionization of IAA. These electrons react with protons and dissolved oxygen to form hydroxyl radicals, which promote the further degradation of atrazine. Montmorillonite strongly enhances the yield of hydrated electrons and prolongs their lifetime, by stabilizing radical cations through electrostatic attraction by the negative charges embedded in the clay. Moreover, by providing a confined space, montmorillonite markedly increases the probability of contact between atrazine and the active radicals. Other factors strongly influencing the degradation process are the solution pH, the type of exchangeable cations present in the clay interlayer, and the hydration status of montmorillonite. Since both IAA and montmorillonite clay are widely distributed in the environment, the proposed reaction is predicted to play an important role in the degradation of atrazine and perhaps other potentially persistent organic contaminants.