Degradation and mechanism analysis of bisphenol A in aqueous solutions by pulsed discharge plasma combined with activated carbon

Degradation of bisphenol A (BPA), an industrial chemical and suspected endocrine disruptor, in a pulsed discharge plasma (PDP) system combined with activated carbon (AC) was investigated in this study. The experimental results showed that the degradation rate of BPA could reach 95.3% after 60 min discharge plasma treatment at 20 kV discharge voltage and the degradation process fitted the first-order kinetic model; degradation rate of BPA was higher in acid solution than that in neutral or alkaline solution; compared to air and nitrogen, the degradation rate of BPA was highest when oxygen was bubbled into the reaction system; the results of spectrum detection indicated the synergistic effect of PDP and AC and the important role of OH and O for the degradation of BPA; the removal of TOC could be 36.8% at the optimal condition; longer discharge plasma treatment time resulted in lower pH value and higher conductivity of treated solution; the increase of absorbance at 240-260 nm in UV-Vis spectra of the BPA solution illustrated the production of intermediates during the degradation process; the degradation pathway was proposed based on the research results and references. Scanning electron microscope (SEM) analysis showed that the surface of the AC after PDP treatment was smoother and AC could be generated by pulse discharge under a certain condition.