Effective degradation of refractory nitrobenzene in water by the natural 4-hydroxycoumarin under solar illumination
Effective degradation of refractory nitrobenzene in water by the natural 4-hydroxycoumarin under solar illumination
复制标题
天然4-羟基香豆素在太阳光照射下有效降解水中难降解硝基苯
DOI：
10.1016/j.chemosphere.2018.10.034
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发表时间：
2019
期刊：
影响因子：
8.8
通讯作者：
Zhouguang Lu
中科院分区：
文献类型：
--
作者：
Tuo Wei;Muhammad Waqas;Ke Xiao;Bo Yang;Yu Luo;Qiuhan Luo;Junmin Zhang;Mingliang Wang;Caizhen Zhu;Tingchao He;Zhouguang Lu
以硝基苯（NB）为典型难降解有机污染物，利用天然有机物（NOMs）在太阳光照射下的化学效应，通过一种新的绿色途径，实现了NB的有效降解。4-羟基香豆素（hydroxycoumarin，4 HC）是一种天然化合物，可从多种植物中提取，在太阳光照射下，4 HC可促进NB光还原为4-氨基苯酚。反应产物经LC-MS/MS和1H NMR确证。通过瞬态吸收光谱（TAS）测量得到了关键中间体4 HC激发态（4 H-chromene-2，4-diol radical，S1）的响应光谱，结果表明S1的衰减时间约为250 ps.然后，电子顺磁共振（EPR）的测量证实了自由基dotOH的存在。据此提出了4 HC与NB反应的机理。此外，还考察了光源、气体环境、溶剂、pH值等因素对反应的影响，进一步揭示了反应过程。
In this study, nitrobenzene (NB) as typical refractory organic pollutants was effectively degraded by a new green approach, which was achieved by the chemical effect of natural organic matters (NOMs) under solar illumination as a potential natural degradation process. 4-hydroxycoumarin (4HC), which is natural compound and can be extracted from many plants, was found as an efficient photosensitizer to promote the photoreduction of NB to 4-aminophenol under the solar illumination. The reaction products were definitely identified by LC-MS/MS and1H NMR. The response spectrum of 4HC excited state (4H-chromene-2,4-diol radical, S1) as key intermediate was also obtained by transient absorption spectroscopy (TAS) measurements, which showed that the decay time of S1was around 250 ps. Then, the measurements of electron paramagnetic resonance (EPR) confirmed the existence of radical dotOH. As a result, the reaction mechanism between 4HC and NB was proposed. In addition, the influence parameters such as light sources, gas surroundings, solvents, pH values were investigated to further reveal the reaction process.