School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China.
Chemosphere. 2018 Feb;193:968-977. doi: 10.1016/j.chemosphere.2017.11.090. Epub 2017 Nov 20.
In this study, significant synergistic degradation of antibiotic diclofenac (DCF) was demonstrated in a novel magnetic field (MF) enhanced zero-valent iron (ZVI)/EDTA Fenton-like system. Five operational parameters, namely, initial ZVI loading, pH, EDTA dosage, DCF concentration and reaction temperature, were investigated for their effects on the DCF degradation. OH was identified as the predominant reactive oxygen species for DCF degradation in ZVI/EDTA systems whether in the presence or absence of MF. DCF molecule can be oxidized by OH, attacking via the hydroxylation and substituted dechlorination of the chlorinated aromatic ring, as well as by dehydration between the N atom and the acetoxyl. It could also be directly dechlorinated by ZVI reduction simultaneously. The reaction mechanism and promotional role of MF in the MF/ZVI/EDTA system were proposed. It is suggested that MF mainly alters the heterogeneous ZVI surface-bond reactions and accelerates the surface corrosion depending on the presence of pristine iron oxides layer, but MF does not change the homogeneous iron cycle and the Fenton-like reactions.
在这项研究中，在一种新型磁场（MF）增强的零价铁（ZVI）/EDTA 类 Fenton 体系中，证明了抗生素双氯芬酸（DCF）的协同显著降解。研究了五个操作参数，即初始 ZVI 负载、pH 值、EDTA 用量、DCF 浓度和反应温度，以研究它们对 DCF 降解的影响。无论是否存在 MF，在 ZVI/EDTA 体系中，OH 被确定为 DCF 降解的主要反应性氧物种。DCF 分子可以被 OH 氧化，通过对氯化芳环的羟基化和取代脱氯以及 N 原子和乙酰氧基之间的脱水进行攻击，也可以通过 ZVI 还原同时直接脱氯。提出了反应机制和 MF 在 MF/ZVI/EDTA 体系中的促进作用。据认为，MF 主要根据原始氧化铁层的存在改变异质 ZVI 表面键反应并加速表面腐蚀，但 MF 不改变均相铁循环和类 Fenton 反应。
