Degradation of p-nitrophenol using a ferrous-tripolyphosphate complex in the presence of oxygen: The key role of superoxide radicals
Degradation of p-nitrophenol using a ferrous-tripolyphosphate complex in the presence of oxygen: The key role of superoxide radicals
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DOI：
10.1016/j.apcatb.2019.118030
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发表时间：
2019-12
影响因子：
22.1
通讯作者：
Chengwu Zhang;Tianyi Li;Jingyi Zhang;Song Yan;Chuanyu Qin
中科院分区：
文献类型：
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作者：
Chengwu Zhang;Tianyi Li;Jingyi Zhang;Song Yan;Chuanyu Qin
铁-聚磷酸盐复合物能活化氧产生活性氧，并能降解有机物，其中dotOH自由基是主要的活性氧。然而，O2·-在这些污染物的降解过程中的作用还没有得到明确的解释。在这项研究中，我们证明，除了产生H2 O2和自由基dotOH外，O2-自由基dotOH还可以直接参与对硝基苯酚（PNP）的降解。EPR分析和探针测试表明，O2·-主要产生于反应的前15 min，在此期间PNP迅速降解。掩蔽实验表明，O2自由基dotH是PNP直接降解的主要活性氧，而不是O2自由基dotH。GC-MS和LC-MS单键确证了O_2自由基将PNP点还原为对氨基苯酚。据此提出了PNP的降解途径。另外两种不同官能团的单环芳烃也进行了研究，以进一步证实O2自由基点-对污染物降解的影响。结果表明，直接降解过程中O2自由基的点参与程度主要取决于污染物的分子结构。此外，在体系中加入四次Fe ~（2+）后，STPP始终保持促进Fe ~（2+）活化O_2的能力。上述结果表明，STPP可以在反应体系中重复使用。
It has been recognized that a ferrous–polyphosphate complex can activate oxygen to produce reactive oxygen species (ROS) capable of degrading organic compounds.radical dotOH has been confirmed as the predominant ROS. However, the role of O2•–during the degradation of these contaminants has not been clearly explained. In this study, we demonstrate that, in addition to producing H2O2andradical dotOH, O2–radical dotcan directly participate in the degradation ofp-nitrophenol (PNP). EPR analysis and probe tests showed that O2•–was largely produced in the first 15 min of the reaction, during which PNP was rapidly degraded. Masking experiments indicated that O2radical dot–, rather than Oradical dotH, was the main ROS for the direct degradation of PNP. GCsingle bondMS and LC-MSsingle bond confirmed that O2radical dot– reduced PNP to p-aminophenol. The PNP degradation pathway was proposed accordingly. Another two monocyclic aromatics with different functional groups were also investigated to further confirm the impact of O2radical dot– on contaminant degradation. It was found that the degree of O2radical dot– participation during direct degradation mainly depends on the molecular structures of the contaminants. In addition, STPP always maintains the ability of promoting Fe2+to activate O2after adding Fe2+four times in the system. The aforementioned results indicate that STPP can be reused in the reaction system.