Abstract By providing the key carbon and nitrogen elements needed for eutrophication, the potential toxicity of ethylenediaminetetraacetic acid (EDTA) prompts the exploration of effective treatment methods to minimize the amount of EDTA released into the environment. In this study, Fe3O4 magnetic nanoparticles (MNPs) were prepared and used as catalysts to study the mineralization of EDTA in Fenton-like reactions under neutral pH. Fe3O4 MNPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET). The effects of pH, ferric ion leaching, and H2O2 concentration on chemical oxygen demand (COD) removal of EDTA were investigated. The morphological characterization of the nanoparticles suggests a quasi-spherical structure with small particle size and a surface area of 49.9 m2/g. The results show that Fe3O4 MNPs had good catalytic activity for the mineralization of EDTA under pH 5.0–9.0. The optimum conditions for the COD removal of 45% at pH 7.0 were: 40 mM H2O2, 10 mM Fe3O4, and 1 g/L EDTANa2·2H2O at 303 K. Fe3O4 MNPs maintained high catalytic activity after five cycles of continuous degradation of EDTA. According to reactive oxidizing species measurements obtained by electron spin resonance (ESR), it was confirmed that HO· free radicals, presented in the H2O2/Fe3O4 MNPs heterogeneous Fenton-like reaction, were the primary active group in the removal of EDTA. These features can be considered beneficial to the application of Fe3O4 MNPs towards industrial wastewater treatment.

中文翻译：

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中性 pH 条件下水溶液中 EDTA 的非均相芬顿降解，增强 COD 去除

摘要通过提供富营养化所需的关键碳和氮元素，乙二胺四乙酸（EDTA）的潜在毒性促使人们探索有效的处理方法，以尽量减少释放到环境中的 EDTA 量。本研究制备了 Fe3O4 磁性纳米颗粒（MNP）并用作催化剂，研究了 EDTA 在中性 pH 下类芬顿反应中的矿化。Fe3O4 MNPs 通过 X 射线衍射 (XRD)、透射电子显微镜 (TEM) 和 Brunauer-Emmett-Teller (BET) 进行表征。研究了 pH、铁离子浸出和 H2O2 浓度对 EDTA 化学需氧量 (COD) 去除的影响。纳米粒子的形态表征表明其具有小粒径和表面积为 49.9 m2/g 的准球形结构。结果表明，Fe3O4 MNPs在pH 5.0~9.0下对EDTA矿化具有良好的催化活性。pH 7.0下COD去除率45%的最佳条件为：40 mM H2O2、10 mM Fe3O4和1 g/L EDTANa2·2H2O，温度303 K。Fe3O4 MNPs在连续降解EDTA的5个循环后仍保持较高的催化活性。根据电子自旋共振（ESR）获得的活性氧化物质测量结果，证实H2O2/Fe3O4 MNPs非均相类芬顿反应中存在的HO·自由基是去除EDTA的主要活性基团。这些特性被认为有利于 Fe3O4 MNP 在工业废水处理中的应用。