School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
J Hazard Mater. 2019 Jun 5;371:456-462. doi: 10.1016/j.jhazmat.2019.03.002. Epub 2019 Mar 1.
Dissolved cobalt ions (Co) are an excellent catalyst for activating peroxymonosulfate (PMS) to generate SO for the degradation of organic pollutants, but fairly high level of Co 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 Co addition is very small, being much less than the emission limit of 17 μmol L. 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 μmol L) was degraded in 20 min by using 2 μmol L Co, 0.15 mmol L PMS and 0.5 mmol L acetate with a degradation rate constant of 0.482 min, which was about 10 times higher than that (0.048 min) of equivalent Co-PMS system without acetate. The formation of SO 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 Co. The enhancement mechanism of SOAs on catalytic activation of PMS by low-level Co was also proposed.
溶解的钴离子（Co）是一种出色的催化剂，可用于激活过一硫酸盐（PMS）以生成 SO，从而降解有机污染物，但通常需要相当高的 Co 水平，这可能会因其毒性而导致二次污染。在此，我们展示了一种新型的催化氧化处理策略，其中所需的 Co 添加量非常小，远低于 17 μmol L 的排放限值。这种新策略基于添加少量有机酸（SOAs）可大大增强催化效果。在典型情况下，在使用 2 μmol L Co、0.15 mmol L PMS 和 0.5 mmol L 乙酸盐的情况下，仅添加 30 μmol L 的双氯芬酸在 20 分钟内完全降解，其降解速率常数为 0.482 min，这比没有乙酸盐的等效 Co-PMS 系统（0.048 min）高约 10 倍。引入乙酸盐可大大增强 SO 的形成，并且该新型体系可普遍增强各种有机污染物的降解效果。类似地，甲酸盐、丙酸盐和丁酸盐也表现出对 Co 催化能力的增强作用。还提出了 SOAs 对低浓度 Co 催化激活 PMS 的增强机制。
