Photoelectrocatalytic based simultaneous removal of multiple organic micro-pollutants by using a visible light driven BiVO4 photoanode

In this research, photoelectrocatalytic (PEC) based advanced oxidation process (AOP) was studied for the removal of multiple OMPs through an oxidative mechanism. This study investigated the application of a BiVO4 photoanode in simultaneous removal of three selected OMPs: acetaminophen (ACT), benzotriazole (BTA) and propranolol (PRO). This study was carried out in demineralized water with a starting concentration of each organic micro-pollutant (OMP) at 45 μg L−1. In order to fabricate BiVO4 photoanodes, a facile and effective dip-coating method was used to deposit BiVO4 photocatalytic layers on fluorine doped tin oxide (FTO) substrate. UV–vis diffusive reflectance spectroscopy, x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) confirmed the successful fabrication of porous BiVO4 photoanode having an absorbance edge at around 526 nm. The fabricated photoanode showed incident photon to current conversion efficiency (IPCE) of 9.23% (λmax=445 nm) under 1 Sun standard illumination. Application of the fabricated photoanodes for the simultaneous removal of ACT, PRO and BTA at an applied voltage of 1 V (vs Ag/AgCl) under solar simulated light resulted in 99% removal of both ACT and PRO, and 70% removal of BTA. The first order rate coefficients and half-life times of ACT and PRO were about three times higher than those of BTA.