Siderite with chelator as high-efficiency Fenton reagent to degrade naphthalene via ferrous liberation and carbon dioxide radical anion-mediated iron redox cycle

• Published in: Journal of water process engineering Vol. 62; p. 105403
• Main Authors: Yang, Rumin, Zeng, Guilu, Sun, Yong, Habib, Mudassir, Zhou, Zhengyuan, Xu, Zhiqiang, Sui, Qian, Fu, Rongbing, Lyu, Shuguang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2024
• Subjects: Chelation; Fenton-like; Iron redox cycle; Naphthalene; Siderite; Fenton-like; Chelation; Iron redox cycle; Naphthalene; Siderite
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105403

Siderite (FeCO3) has been verified to be an effective iron material in Fenton-like process, but large dose of FeCO3 and oxidants limits its application. Here, chelators were successfully used to enhance the degradation of naphthalene (NAP). When 1.0 mM of hydrogen peroxide (H2O2) and 1.0 g L−1 of FeCO3 were applied, in the presence of 0.2 mM oxalic acid (OA), 0.1 mM nitrilotriacetic acid (NTA), or 0.1 mM DL-tartaric acid (DL-TA), 99.3 %, 100 %, or 96.7 % of NAP was degraded within 24 h, respectively. The different roles of chelators were confirmed. For OA and DL-TA, due to weak complexation with iron ions, acid effect and generation of carbon dioxide radical anion (CO2−) contributed to high concentration of Fe2+, while for NTA, chelation and CO2− were two major factors. In addition, the excellent potential application of H2O2/FeCO3/chelator was determined because of (1) lower environmental risk of chemicals; (2) strong tolerance to water matrixes; (3) the excellent stability of FeCO3 confirmed by surface characterizations and cyclic experiment, as NAP was completely degraded after the 6th cycle. At last, H2O2/FeCO3/chelator had superiority over other reduced iron minerals due to lower running cost in lab study, better reusability, and environmental friendliness. Therefore, it is expected that H2O2/FeCO3/chelator technique can provide an effective alternative to Fenton-like process in remediation of NAP contaminated sites. [Display omitted] •Siderite with chelator achieved effective degradation of naphthalene.•For OA and DL-TA, acidification and formation of CO2− were two major mechanisms.•For NTA, chelation and formation of CO2− dominated.•Excellent stability and reusability of siderite was confirmed.•Superiority of siderite over FeS and pyrite was discussed.