Determination of optimum process parameters for peroxidase‐catalysed treatment of bisphenol A and application to the removal of bisphenol derivatives

Abstract

Systematic investigations were carried out to determine the optimum process parameters such as the hydrogen peroxide (H₂O₂) concentration, concentration and molar mass of poly(ethylene glycol) (PEG) as an additive, pH value, temperature and enzyme dose for treatment of bisphenol A (BPA) with horseradish peroxidase (HRP). The HRP‐catalysed treatment of BPA was effectively enhanced by adding PEG, and BPA was completely converted into phenoxy radicals by HRP dose of 0.10 U/cm³. The optimum conditions for HRP‐catalysed treatment of BPA at 0.3 mM was determined to be 0.3 mM for H₂O₂ and 0.10 mg/cm³ for PEG with a molar mass of 1.0 × 10⁴ in a pH 6.0 buffer at 30 °C. Different kinds of bisphenol derivatives were completely or effectively treated by HRP under the optimum conditions determined for treatment of BPA, although the HRP dose was further increased as necessary for some of them. The aggregation of water‐insoluble oligomers generated by the enzymatic radicalization and radical coupling reaction was enhanced by decreasing the pH values to 4.0 with HCl after the enzymatic treatment, and BPA and bisphenol derivatives were removed from aqueous solutions by filtering out the oligomer precipitates.

Keywords:

• horseradish peroxidase
• bisphenol A
• bisphenol derivatives
• oligomer precipitate
• water purification