Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, Jilin Provincial Key Laboratory of Water Resource and Environment, College of New Energy and Environment, Jilin University, 2519 Jiefang Road, Changchun 130021, PR China.
Key Laboratory of Groundwater Resources and Environment of the Ministry of Education, Jilin Provincial Key Laboratory of Water Resource and Environment, College of New Energy and Environment, Jilin University, 2519 Jiefang Road, Changchun 130021, PR China.
J Hazard Mater. 2021 Aug 15;416:126077. doi: 10.1016/j.jhazmat.2021.126077. Epub 2021 May 11.
N,N-bis(carboxymethyl)glutamic acid (GLDA) was utilized in this study to significantly enhance the Fe(III) mediated Fenton-like oxidation removal of organic pollutants at neutral pH, in which ciprofloxacin (CIP) was used as the model pollutant. The CIP degradation rate in the GLDA/Fe(III)/HO system reached 96.5% within 180 min and was nearly 14 times higher than that in the Fe(III)/HO system. This enhancement was contributed to the acceleration of the cycle of Fe(III)/Fe(II) caused by GLDA, which was verified by UV-vis spectroscopy, cyclic voltammetry, and radical quenching experiments. The results proved that the GLDA could complex with Fe(III) and greatly modify the redox potential of Fe(III)/Fe(II). Moreover, radical quenching experiments confirmed that •OH and O were the mainly species for CIP degradation, and O was responsible for 81.9% •OH generation. In addition, HO utilization kinetic modeling was also investigated. The optimum parameters of the 100 μM Fe(III)-GLDA complex and 15 mM HO were attained by lot-size optimization experiments. Two possible CIP degradation pathways were proposed on the basis of the intermediates identified by MS/MS. The GLDA/Fe(III)/HO system performed better than common chelating agents at the same condition, manifesting good potential for environmental concerns.
N,N-双（羧甲基）谷氨酸（GLDA）在这项研究中被用于在中性 pH 值下显著增强 Fe(III)介导的芬顿样氧化去除有机污染物的能力，其中环丙沙星（CIP）被用作模型污染物。在 GLDA/Fe(III)/HO 体系中，CIP 的降解速率在 180 分钟内达到 96.5%，几乎是 Fe(III)/HO 体系的 14 倍。这种增强归因于 GLDA 加速了 Fe(III)/Fe(II)的循环，这通过紫外-可见光谱、循环伏安法和自由基猝灭实验得到了验证。结果证明 GLDA 可以与 Fe(III)络合，并极大地改变 Fe(III)/Fe(II)的氧化还原电位。此外，自由基猝灭实验证实•OH 和 O 是 CIP 降解的主要物质，O 负责 81.9%的•OH 生成。此外，还研究了 HO 利用动力学模型。通过批量优化实验获得了 100μM Fe(III)-GLDA 配合物和 15mM HO 的最佳参数。基于 MS/MS 鉴定的中间体，提出了两种可能的 CIP 降解途径。GLDA/Fe(III)/HO 体系在相同条件下优于常见的螯合剂，表现出良好的解决环境问题的潜力。
