Dramatically enhanced aerobic atrazine degradation with Fe@Fe2O3 core-shell nanowires by tetrapolyphosphate.
Dramatically enhanced aerobic atrazine degradation with Fe@Fe2O3 core-shell nanowires by tetrapolyphosphate.
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DOI：
10.1021/es404741x
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发表时间：
2014-02
影响因子：
11.4
通讯作者：
Li Wang;M. Cao;Zhihui Ai;Lizhi Zhang
中科院分区：
文献类型：
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作者：
Li Wang;M. Cao;Zhihui Ai;Lizhi Zhang
在中性到碱性的pH范围内（pH6.0 -9.0），系统研究了无机配体四聚磷酸盐对Fe@Fe2O3核壳纳米线分子氧活化及后续阿特拉津好氧降解的影响.我们有趣地发现，四聚磷酸盐的加入可以使阿特拉津的好氧降解率提高955倍，甚至是传统有机配体乙二胺四乙酸盐的10倍。这种四聚磷酸盐诱导的阿特拉津好氧降解增强可以归因于两个因素。一个是四聚磷酸盐的存在强烈抑制了Fe@Fe2O3核壳纳米线通过质子限制还原质子的析氢，留下更多的电子用于Fe（III）还原为Fe（II）和随后的分子氧活化。二是四聚磷酸盐与亚铁离子的络合作用不仅保证了芬顿反应所需的可溶性Fe（II），而且为单电子分子氧还原途径提供了另一条产生更多·OH的途径。采用气相色谱-质谱联用技术和液相色谱-质谱联用技术对阿特拉津的降解中间体进行了鉴定，并提出了阿特拉津可能的好氧降解途径。该研究不仅揭示了配体对纳米零价铁活化分子氧的促进作用，而且为阿特拉津的氧化去除提供了一种简便、绿色的铁基方法.
In this study, the effects of an inorganic ligand tetrapolyphosphate on the molecular oxygen activation and the subsequent aerobic atrazine degradation by Fe@Fe2O3 core-shell nanowires were investigated systematically at a circumneutral to alkaline pH range (pH 6.0-9.0). We interestingly found that the addition of tetrapolyphosphate could enhance the aerobic atrazine degradation rate 955 times, which was even 10 times that of the traditional organic ligand ethylenediamine tetraacetate. This tetrapolyphosphate induced dramatic aerobic atrazine degradation enhancement could be attributed to two factors. One was that the presence of tetrapolyphosphate strongly suppressed hydrogen evolution from the reduction of proton by Fe@Fe2O3 core-shell nanowires through proton confinement, leaving over more electrons for the reduction of Fe(III) to Fe(II) and the subsequent molecular oxygen activation. The other was that the complexation of tetrapolyphosphate with ferrous ions not only guaranteed enough soluble Fe(II) for Fenton reaction, but also provided another route to produce more •OH in the solution via the single-electron molecular oxygen reduction pathway. We employed gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry to identify the atrazine degradation intermediates and proposed a possible aerobic atrazine degradation pathway. This study not only sheds light on the promotion effects of ligands on the molecular oxygen activation by nanoscale zerovalent iron, but also offers a facile and green iron-based method for the oxidative atrazine removal.