Efficient removal of ciprofloxacin by peroxymonosulfate/Mn3O4-MnO2 catalytic oxidation system
Efficient removal of ciprofloxacin by peroxymonosulfate/Mn3O4-MnO2 catalytic oxidation system
复制标题
过一硫酸盐/Mn3O4-MnO2催化氧化体系高效去除环丙沙星
DOI：
10.1016/j.cej.2017.06.064
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发表时间：
2017
影响因子：
15.1
通讯作者：
Yang Chun
中科院分区：
文献类型：
--
作者：
Zhao Zhiwei;Zhao Jianhui;Yang Chun
本文合成了新型多价mn3o4 - mno2复合催化剂，并将其用于过氧单硫酸盐（PMS）活化，实现环丙沙星（CIP）的降解。结果表明，在PMS/Mn3O4-MnO2体系中，PMS用量为1 mM， Mn3O4-MnO2用量为0.1 g/L， PMS/Mn3O4-MnO2体系中，CIP （50 μM）的去除率为97.6%。CIP降解符合准一级动力学模型，最高动力学常数为0.139 min−1。此外，还考察了溶液pH、共存阴离子和天然有机物对CIP去除率的影响。PMS/ mn3o4 - mno2体系去除CIP的最佳pH为中性。同时存在的阴离子HCO3−、NO3−和SO42−抑制了降解过程，而Cl−则促进了降解过程。天然有机质（NOM）在1.0 mg/L时对CIP的降解有积极作用，而在3.0和5.0 mg/L时则有不利影响。进一步分析了mn3o4 - mno2活化PMS的机理。mn3o4 - mno2复合材料中Mn(III)/Mn（II）和Mn(IV)/Mn（III）氧化还原对PMS具有很强的硫酸盐自由基和氢氧自由基活性。据此，确定了CIP的转化产物，并提出了PMS/ mn3o4 - mno2体系中CIP的降解途径。这些发现对通过PMS氧化系统去除水中抗生素具有重要意义。
In this work, the novel multivalent Mn3O4-MnO2composite catalyst was synthesized and employed for peroxymonosulfate (PMS) activation to realize ciprofloxacin (CIP) degradation. Results showed that 97.6% of CIP (50 μM) was removed in PMS/Mn3O4-MnO2system by adsorption and further degradation within 25 min at the dosage of 1 mM PMS and 0.1 g/L Mn3O4-MnO2. The CIP degradation followed the pseudo-first-order kinetic model and the highest kinetic constant of 0.139 min−1was achieved. Moreover, the effects of solution pH, coexisting anions and natural organic matter on CIP removal were investigated. The optimum pH in PMS/Mn3O4-MnO2system for CIP removal was neutral. The coexisting anions such as HCO3−, NO3−and SO42−inhibited the degradation process while Cl−enhanced the process. The natural organic matter (NOM) presented positive effect on CIP degradation at 1.0 mg/L and detrimental effect at 3.0 and 5.0 mg/L. Furthermore, the mechanism of PMS activation by Mn3O4-MnO2was interpreted. The PMS was highly activated to sulfate and hydroxide radicals by the redox pairs of Mn(III)/Mn(II) and Mn(IV)/Mn(III) in Mn3O4-MnO2composite. Accordingly, the transformation products of CIP were determined and the degradation pathways in PMS/Mn3O4-MnO2system were proposed. These findings would make a significant contribution towards removing antibiotics from water through PMS oxidation system.