Improving the photocatalytic activity of silver orthophosphate by thermal annealing for photocatalytic degradation of β-naphthol

beta-naphthol, a highly toxic compound, can be absorbed through the skin and exposure to it increases the incidence of dermatitis, conjunctivitis, and rhinitis. In this study, silver orthophosphate (Ag3PO4) photocatalyst was successfully prepared via a simple thermal annealing route to remove beta-naphthol from water under simulated visible light. The characteristics of prepared photocatalyst were measured by scanning electron microscopy (SEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), UV-vis diffuse spectra (UV-vis DRS), and photoluminescence (PL). Moreover, the photocatalytic activity was studied using different parameters such as catalyst concentration, substrate concentration, reaction pH, humic acid concentration, and in the presence of various common anions. All parameters except solution pH were statistically significant. It can be observed that 98.5% of beta-naphthol can be degraded. The active species trapping experiments indicated that both h(+) and O-center dot(2-) played prominent roles in the photodegradation of beta-naphthol. It also showed that the catalyst annealed at 400 degrees C exhibited the best stability and reproducibility. In addition, this study identified the intermediate products produced during the reaction process to support the photocatalysis mechanism.