The photochemical decomposition and detoxification of bisphenol A in the VUV/H2O2 process: Degradation, mineralization, and cytotoxicity assessment

Abstract

The present study investigates the novel advanced process of VUV/H2O2 for oxidation of bisphenol A (BPA) known as an endocrine disrupting compound (EDC) which is released from the human and industrial activities. The effect of water pH, H2O2 and BPA concentrations, reaction time and presence of anions and scavengers were examined on the BPA degradation and mineralization in the VUV/H2O2 batch process. The optimum values of solution pH and H2O2/BPA mass ratio were found to be 3 and 4, respectively. The oxidation with hydroxyl radicals was the main mechanism involved in the BPA degradation. The rate of BPA degradation under optimum conditions observed to be increased from 20.5 to 50.8mg/L.min when the BPA concentration was increased from 20 to 100mg/L. The main anions did not majorly affect the BPA degradation in the VUV/H2O2 process. 97.6% of BPA was mineralized within 60min in the VUV/H2O2 process under optimum conditions. The cytotoxicity of the BPA significantly decreased after treating in the VUV/H2O2 process. The complete degradation of BPA was obtained in the continuous-flow VUV/H2O2 process at a hydraulic retention time (HRT) as short as 8min whereas only 48.2% of BPA could be degraded in the single VUV under similar experimental conditions. The electrical energy consumed per order (EE/O) of degraded BPA was 2.4 and 4.2kWh/m3 for initial BPA concentrations between 20 and 100mg/L. Accordingly, the VUV/H2O2 process is found to be a very efficient and cost-effective process for oxidation of BPA.