Photoelectrocatalytic degradation of endocrine-disruptor bisphenol – A with significantly activated peroxymonosulfate by Co-BiVO4 photoanode

Abstract

Bisphenol A (BPA) is known as an endocrine-disrupting chemical, generally present in the environment. It has a harmful effect on aquatic lives and human health, therefore it is needful to exploit highly efficient innovative treatment methods for its removal. Herein, we report a Co-BiVO4 photoanode to activate peroxymonosulfate (PMS) for the complete removal of BPA via a photoelectrochemical (PEC) process. The Co-BiVO4 could degrade 99.16% of BPA in the presence of 2 mM PMS within 60 min, whereas the degradation rate constant is 0.08034 min−1, which was 20.86 times higher than the electrocatalytic (EC) and 5.35 times higher than the photocatalytic (PC) process. Notably, Co-BiVO4 showed significant activity toward PMS activation and BPA degradation as compared to other synthesized photocatalysts. Their photoelectrocatalytic performance followed the sequence Co-BiVO4 > Fe-BiVO4 > Ni-BiVO4 > pure-BiVO4 > without catalysts. Several influencing factors on the decomposition process, such as the effect of PMS concentration, applied potential, illumination time, initial pH, BPA concentration, Co loading, and co-existing anions were studied in detail. Radical scavenging experiment and transient absorption result showed that sulfate radicals (SO4•─) were the dominant reactive species. Moreover, a significant synergistic effect was noticed in Co-BiVO4/PEC/PMS system for BPA degradation. Degradation mechanism and reaction intermediates were studied by in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) and liquid chromatography-mass spectroscopy (LC-MS) presenting the enhanced bond cleavage in PEC activated PMS system. The BPA showed 92.47% and 87.27% removal in tap and river water samples after 60 min of reaction using Co-BiVO4/PMS PEC system. Our finding proposed an efficient method for wastewater treatment in an eco-friendly way.