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Title |
Ferrate(VI) Oxidation of Naturally Occurring Hazardous Aromatic Precursors: Principle-Based Reaction Kinetics and Application to Nakdong River Water
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Authors |
김진평(Jinpyeong Kim) ; 가이레아마르(Amar Gaire) ; 박민서(Min Seo Park) ; 박상준(Sang Jun Park) ; 홍석범(Seok Beom Hong) ; 조민(Min Cho) ; 윤영건(Younggun Yoon) ; 신재돈(Jaedon Shin) |
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DOI |
https://doi.org/10.15681/KSWE.2026.42.1.14 |
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Keywords |
Agricultural water; Allelopathy; Disinfection byproducts; Drinking water; Ferrate (VI) oxidation |
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Abstract |
Benzoic acid derivatives (BADs) are increasingly found in natural waters used for drinking and agriculture, raising concerns about their transformation into disinfection byproducts (DBPs) during oxidative treatment and their potential allelopathic effects that can hinder plant growth. This study systematically evaluated the degradation of two representative BADs: para-aminobenzoic acid (p-ABA) and para-chlorobenzoic acid (p-CBA), using ferrate(VI) [Fe(VI)] under controlled and environmentally relevant conditions. The results indicated that Fe(VI) effectively degraded p-ABA, while p-CBA showed negligible reactivity due to differences in their electron density and substituent effects. For p-ABA, the apparent second-order rate constants (kapp) under compound-excess conditions ranged from 78 to 1,692 M-1s-1 at pH 6?8. In contrast, under Fe(VI)-excess conditions, kapp’ values ranged from 180 to 625 M-1s-1, with degradation rates influenced by the Fe(VI) dosage. A tentative degradation pathway was proposed, based on existing literature, suggesting the initial formation of an aniline radical cation, which may then transform into nitro- or azo-derivatives that are structurally persistent and could pose environmental risks. Experiments conducted with natural river water from the Nakdong River in Korea showed greater removal of p-ABA than predicted by phosphate-buffered models. This indicates that dissolved organic matter and other background constituents can enhance degradation through secondary reactive species such as Fe(IV) and Fe(V), or through alternative pathways. The observed >95% removal at Fe(VI)≥0.5 mg Fe/mg DOC highlights the effectiveness of Fe(VI) oxidation in complex water matrices. These findings enhance the understanding of Fe(VI)-based oxidation, provide insights for optimizing treatment processes under realistic conditions, and underscore its potential as a selective and sustainable strategy for treating BADs in drinking water and agricultural reuse systems
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