Degradation of atrazine by manganese-catalysed ozonation: Influence of humic substances
Degradation of atrazine by manganese-catalysed ozonation: Influence of humic substances
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DOI：
10.1016/s0043-1354(98)00266-8
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发表时间：
1999-02-01
期刊：
影响因子：
12.8
通讯作者：
Graham, NJD
中科院分区：
文献类型：
--
作者：
Ma, J;Graham, NJD
使用常规的气泡接触柱，在有锰存在的情况下，对阿特拉津的臭氧化进行了实验室规模的研究。锰在溶液中以二价锰（Mn(II)）或原位形成的四价锰（Mn(IV)）的形式存在。实验结果表明，腐殖质的存在对锰催化的阿特拉津臭氧化有重大影响。在少量腐殖质存在的情况下（例如，以DOC计为1毫克/升），锰催化的臭氧化明显增强。然而，随着腐殖质浓度的进一步增加，对于二价锰和四价锰这两种情况，都观察到腐殖质对阿特拉津催化氧化的负面影响。据推测，锰催化的阿特拉津臭氧化遵循自由基型机制。在腐殖质浓度较低时，锰物种和腐殖质都可能在臭氧化过程中引发和促进羟基自由基的形成，从而增强对阿特拉津的破坏。然而，在较高浓度时，腐殖质可能会清除这些高活性的羟基自由基，从而降低阿特拉津的氧化效率。（C）1998年，爱思唯尔科学有限公司。版权所有。
A bench-scale, laboratory study has been undertaken on the ozonation of atrazine in the presence of manganese using a conventional gas bubble-contacting column. Manganese was present in solution either as Mn(II) or as in situ formed Mn(IV). The experimental results indicate that the presence of humic substances has a substantial influence on the Mn-catalysed ozonation of atrazine. In the presence of a small amount of humic substances (e.g. 1 mg/l as DOG), the Mn-catalysed ozonation is obviously enhanced. However, with the further increase of humic substance concentration, a negative effect of humic substances on the catalytic oxidation of atrazine is observed for both the cases of Mn(ll) and Mn(IV). It is proposed that Mn-catalysed ozonation of atrazine follows a radical-type mechanism. At low concentrations of humic substances, both the manganese species and the humic substances may initiate and promote the formation of hydroxyl radicals during ozonation which enhance the destruction of atrazine. However, at higher concentrations, humic substances may scavenge these highly reactive hydroxyl radicals, thus decreasing the oxidation efficiency of atrazine. (C) 1998 Elsevier Science Ltd. All rights reserved.