Performance evaluation and optimization of ZnO-PVP nanoparticles for photocatalytic wastewater treatment: Interactions between UV light intensity and nanoparticles dosage

In recent decades, the application of nanoparticles for environmental remediation purposes has received great attention due to their promising removal efficiency. In this research, we evaluated photocatalytic performance of synthesized zinc oxide-polyvinylpyrrolidone (ZnO-PVP) as modified ZnO nanoparticles for chemical oxygen demand (COD) reduction and phosphate removal from municipal wastewater. Furthermore, the synergistic effect of UV light intensity and ZnO-PVP dosage on photocatalytic treatment was investigated. To do this, after characterization of the synthesized ZnO-PVP nanoparticles by SEM, EDX, FTIR, XRD, UV–Vis DR spectroscopy and BET analysis, the effect of ZnO-PVP and single ZnO treatment on COD reduction and phosphate removal was compared using different dosages of nanoparticles (1, 1.5, 2 and 2,5 g/L). The interaction effects of UV light intensity and nanoparticles dosage were investigated by performing 12 batch experiments. The results proved that using ZnO-PVP could improve the photocatalytic treatment of COD (from 63% to 83%) and phosphate (from 68% to 87%), in comparison with single ZnO. It has been observed that UV light intensity directly affects ZnO-PVP photocatalytic treatments performance. Maximum removal efficiencies of 95% and 97% were achieved for COD and phosphate, respectively, under optimal condition of ZnO-PVP dosage of 1.5 g/L and UV intensity of 2293 mW/cm2. This research suggests that under the optimal condition, ZnO-PVP nanoparticles can be used as a promising approach for COD reduction and phosphate removal from wastewater.