Enhanced Degradation of Paracetamol by the Fe(III)-Sulfite System under UVA Irradiation |
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Authors: | Yanan Yuan Feng Wu Marcello Brigante Gilles Mailhot |
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Affiliation: | 1.Yichang Atmospheric Pollution Prevention and Control Administrative Center, Yichang 435000, China;2.Department of Environmental Science, School of Resources and Environmental Science, Wuhan University, Wuhan 430079, China;3.Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, CNRS, Clermont Auvergne INP, F-63000 Clermont-Ferrand, France; |
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Abstract: | The Fe(III)-S(IV) system used for advanced oxidation processes (AOPs) at acidic pH has just been proposed and demonstrated valid for very few contaminants in the last several years. In this work, we investigated the effect of ultraviolet A (UVA) radiation on the degradation efficiency of the Fe(III)/S(IV) system at near-neutral pH. Paracetamol (PARA) was selected as a model contaminant. The influencing factors, such as initial pH and Fe(III)/S(IV) molar ratio on chemical kinetics, and the mechanism of PARA degradation are investigated, with an emphasis on the determination of dominant oxidant species. Our results show that irradiation enhances the PARA degradation by accelerating the decrease of pH to acidic levels, and the optimal pH for the degradation of PARA in the Fe(III)/S(IV)/O2 system was around 4.0. At near-neutral pH, more than 60% of PARA was decomposed within 40 min under irradiation, whereas no significant degradation of PARA was observed using Fe(III)/S(IV) at pH 7.0 without irradiation. Mechanism investigation revealed that sulfate radical (SO4•‒) is the main oxidant species generated and responsible for the PARA degradation under these conditions. This finding may have promising implications in developing a new degradation process for dealing with wastewater at near-neutral pH by the Fe(III)/S(IV)/O2 system under UVA irradiation. |
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Keywords: | paracetamol photodegradation Fe(III) sulfite ions sulfate radical |
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