Degradation of Bisphenol-A by Ozonation

Abstract

AbstractThe study reports the degradation of an endocrine disrupting compound- bisphenol A (BPA) by ozonation at slightly acidic pH with emphasis on the operational parameters (e.g. BPA concentration, ozone addition and mass transfer rate, contact time), reaction kinetics, rate constants and oxidation byproducts. It was found that the rate of BPA decay (pseudo-first order with respect to concentration) was accelerated with increased ozone addition rate and decreased BPA initial concentration. The profile of aqueous ozone concentration was such that it remained constant during 1-3 min of contact and increased thereafter. The bimolecular reaction rate constant was estimated using the steady state concentration of ozone and the value found was in good agreement with those reported in the literature for similar pH. Total mineralization was most rapid before complete conversion of BPA and much slower thereafter, implying low reactivity of the intermediate products with ozone. Mineralization was enhanced by alkalinization to pH 10.8, which facilitated the overall degradation process via the formation of radical species that were less selective than ozone. Byproducts of oxidation in successive order of formation were p-tert-butylphenol, hydroquinone, methyl-dihydrobenzofuran and n-butyl acetate, none of which are classified as endocrine disruptors.