Novel real-time method using the stopped-flow for evaluating bisphenol A degradation kinetics by molecular ozone and radical mechanisms |
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Authors: | V Flores-Payán E León-Becerril A López-López |
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Affiliation: | Environmental Technology Department, Centro de Investigación y Asistencia en Tecnología y Dise?o del Estado de Jalisco, Guadalajara, Jalisco, Mexico |
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Abstract: | A novel real-time method was developed to evaluate the bisphenol A degradation kinetics by molecular ozone and radical pathway using the stopped-flow technique. The second-order kinetics was determined under pseudo-first-order conditions for the molecular pathway by the absolute rate constant method and for the radical pathway by the Rct concept involving the hydroxyl radical and ozone ratio. Bisphenol A degradation by ozone was performed and evaluated at a pH ranging from 2 to 10. At pH?4 (molecular pathway), the second-order rate constant value was 1.12?×?104?M?1?s?1 and for the radical pathway at pH?>?10, the constant was 3.43?×?109?M?1?s?1. To validate the method, ciprofloxacin degradation kinetics was determined at pH 8 by radical pathway, in 4.55?×?109?M?1?s?1. The method permits the determination of kinetic parameters for the design of chemical reactors; avoiding the generation of undesirable reactions and by-products in the degradation of emerging compounds. |
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Keywords: | Bisphenol A HO?-probe Ozone pCBA Second-order rate constants Stopped-flow |
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