Protocatechuic Acid Promoted Alachlor Degradation in Fe(III)/H2O2 Fenton System
Protocatechuic Acid Promoted Alachlor Degradation in Fe(III)/H2O2 Fenton System
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原儿茶酸促进 Fe(III)/H2O2 Fenton 体系中甲草胺的降解
DOI：
10.1021/es506110w
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发表时间：
2015-07-07
影响因子：
11.4
通讯作者：
Zhang, Lizhi
中科院分区：
文献类型：
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作者：
Qin, Yaxin;Song, Fahui;Zhang, Lizhi
在本研究中，我们证明了原儿茶酸(PCA)能显著促进Fe(III)/H_2O_2-Fenton氧化体系中甲草胺的降解。结果表明，在pH=3.6的Fenton氧化体系中，加入原儿茶酸可使甲草胺的降解率提高10000倍。甲草胺降解的显著提高归因于原儿茶酸配体的络合和还原能力，它可以与铁离子形成稳定的络合物以防止其沉淀，并加速Fe(III)/Fe(II)循环以促进中心点OH的生成。同时，Fe(III)/PCA/H_2O_2体系也能在接近自然pH的条件下工作，即使在PCA浓度低至0.1 mmol/L的情况下，甲草胺和PCA也能被有效地矿化，表明PCA/Fe(III)/H_2O_2-Fenton体系对环境友好。利用气相色谱-质谱法对甲草胺的降解中间体进行了鉴定，提出了甲草胺在Fenton氧化体系中可能的降解机理。本研究为去除氯乙酰苯胺类除草剂提供了一条有效的途径，并对天然水环境中广泛存在的酚酸在有机污染物转化和矿化中的可能作用提供了新的见解。
In this study, we demonstrate that protocatechuic acid (PCA) can significantly promote the alachlor degradation in the Fe(III)/H2O2 Fenton oxidation system. It was found that the addition of protocatechuic acid could increase the alachlor degradation rate by 10 000 times in this Fenton oxidation system at pH = 3.6. This dramatic enhancement of alachlor degradation was attributed to the complexing and reduction abilities of protocatechuic ligand, which could form stable complexes with ferric ions to prevent their precipitation and also accelerate the Fe(III)/Fe(II) cycle to enhance the center dot OH generation. Meanwhile, the Fe(III)/PCA/H2O2 system could also work well at near natural pH even in the case of PCA concentration as low as 0.1 mmol/L. More importantly, both alachlor and PCA could be effectively mineralized in this Penton system, suggesting the environmental benignity of PCA/Fe(III)/H2O2 Fenton system. We employed gas chromatography-mass spectrometry to identify the degradation intermediates of alachlor and then proposed a possible alachlor degradation mechanism in this novel Fenton oxidation system. This study provides an efficient way to remove chloroacetanilide herbicides, and also shed new insight into the possible roles of widely existed phenolic Acids in the conversion and the mineralization of organic Contaminants in natural aquatic environment.