Oxidative degradation of bisphenol A by Bio-Fenton reaction equipped with glucose oxidase and ferric citrate: Degradation kinetics and pathway

Abstract

The Bio-Fenton reaction was applied to degrade bisphenol A (BPA, 0.1 mM), a commonly used plastic additive, via in-situ produced hydrogen peroxide (H2O2) from glucose oxidase (GOx, 10 U), glucose (32 mM), and Fe(III)-citrate (0.5 mM) at pH 5.3. The reaction produced 0.15–1.1 × 10−16 M of •OH at a steady-state ([•OH]ss), which contributed significantly to BPA degradation. The second-order rate constant (k) for BPA degradation was 1.39–2.38 × 109 M−1 s−1, with 80% degradation of 0.1 mM BPA in 10 days of incubation and the production of hydroxylated intermediates, 4-hydroxyacetophenone, and hydroquinone, which were further filtered into small carboxylic acids via •OH-mediated reactions: hydroxylation, oxidation, scission of the C-C bond between the two BPA aromatic rings, and ring cleavage. Based on the successful application of the Bio-Fenton reaction to the radical scavenger and plastic additive BPA, microorganisms capable of producing H2O2 through diverse oxidase enzymatic systems can be applied to degrade diverse pollutants in environments where ubiquitous Fe(III) with organic iron chelators is present.