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Oxidative degradation of triazine- and sulfonylurea-based herbicides using Fe(VI): The case study of atrazine and iodosulfuron with kinetics and degradation products
Citation:
Zajicek, P., M. Kolar, R. Prucek, V. Ranc, P. Bednar, R. Varma, V. Sharma, AND R. Zboril. Oxidative degradation of triazine- and sulfonylurea-based herbicides using Fe(VI): The case study of atrazine and iodosulfuron with kinetics and degradation products. SEPARATION AND PURIFICATION TECHNOLOGY. Elsevier Science Ltd, New York, NY, 156(Part 3):1041-1046, (2015).
Impact/Purpose:
Prepared for submission to journal, Separation and Purification Technology
Description:
The occurrence of common herbicides (Atrazine, ATZ and Iodosufuron, IDS), in waters presents potential risk to human and ecological health. The oxidative degradation of ATZ and IDS by ferrate(VI) (FeVIO42-, Fe(VI)) is studied at different pH levels where kinetically observed second-order rate constants (kapp, M-1s-1) decreased with increase in pH from 6.0 – 9.0. The determination of the rate constants for the Fe(VI) species, HFeO4- and FeO42-, with the herbicides using acid-base equilibria of Fe(VI) suggested that the HFeO4- species was largely responsible for the pH dependence behavior of kapp. The title herbicides degraded > 90 % within 10 minutes using excess weighted amounts of Fe(VI) over IDS (2:1) ATZ (20:1) and in the pH range of 6.0 – 9.0. Comparatively, degradations of ATZ and IDS by Mn(VII) were ~ 70 % and~ 40 % under same conditions; - showing a superior efficiency of ferrate(VI) in degradation of toxic herbicides. The oxidized products of ATZ and IDS by Fe(VI) at a neutral pH were examined by liquid chromatography-tandem mass spectrometry (LC/MS/MS) analysis, which indicated that Fe(VI) attacked on the sulfonamide and alkyl chain moieties of ATZ and IDS, respectively.
