Efficient degradation of organic pollutants by low-level Co2+ catalyzed homogeneous activation of peroxymonosulfate
Efficient degradation of organic pollutants by low-level Co2+ catalyzed homogeneous activation of peroxymonosulfate
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低含量Co2催化过一硫酸盐均相活化高效降解有机污染物
DOI：
10.1016/j.jhazmat.2019.03.002
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发表时间：
2019-06-05
影响因子：
13.6
通讯作者：
Tang, Heqing
中科院分区：
文献类型：
--
作者：
Chen, Mantang;Zhu, Lihua;Tang, Heqing
溶解态钴离子（Co2+）是活化过一硫酸盐（PMS）生成SO 4中心点-的优良催化剂，可用于降解有机污染物，但通常需要较高的Co2+含量，且由于其毒性，易造成二次污染。在这里，我们展示了一种新的策略，这种催化氧化处理，其中所需的Co2+添加是非常小的，远低于17摩尔L-1的排放限值。这种新的策略是基于通过添加小有机酸（SOA）大大增强的催化效果。在典型的情况下，所有添加的双氯芬酸（30 μ mol L-1）在20分钟内被降解，使用2 μ mol L-1的钴2+，0.15 mmol L-1的PMS和0.5 mmol L-1的乙酸，降解速率常数为0.482 min（-1），这是约10倍，比相当的钴2 +-PMS系统（0.048 min（-1））没有乙酸。乙酸根的引入大大促进了SO 4中心点的形成，这种新体系对各种有机污染物的强化降解具有普适性。同样，甲酸，丙酸，丁酸也表现出增强效果的Co2+的催化能力。提出了SOAs对低浓度Co2+催化活化PMS的增强机理。
Dissolved cobalt ions (Co2+) are an excellent catalyst for activating peroxymonosulfate (PMS) to generate SO4 center dot- for the degradation of organic pollutants, but fairly high level of Co2+ is generally required, which may cause secondary pollution due to its toxicity. Herein, we demonstrate a novel strategy for this catalytic oxidation treatment in which the required Co2+ addition is very small, being much less than the emission limit of 17 mol L-1. This new strategy is based on the much enhanced catalytic effect by the addition of small organic acids (SOAs). In a typical case, all the added diclofenac (30 mu mol L-1) was degraded in 20 min by using 2 mu mol L-1 Co2+, 0.15 mmol L-1 PMS and 0.5 mmol L-1 acetate with a degradation rate constant of 0.482 min(-1), which was about 10 times higher than that (0.048 min(-1)) of equivalent Co2+-PMS system without acetate. The formation of SO4 center dot- was greatly enhanced by introducing acetate, and this novel system is universal for enhanced degradation of various organic pollutants. Similarly, formate, propionate, and butyrate also exhibited enhancing effects on the catalytic ability of Co2+. The enhancement mechanism of SOAs on catalytic activation of PMS by low-level Co2+ was also proposed.