Optimization of Vancomycin Antibiotic Removal from Synthetic and Real Wastewater Using UV/Fe₃ O₄ @Alg-ZnO Nanocomposite Photocatalysis: Response Surface Methodology Based on a Box-Behnken Design

Abstract

Background: Vancomycin (VCM) is a critical antibiotic due to its high consumption and side effects, including increased bacterial resistance affecting treatment processes. This research investigated the efficiency of VCM antibiotic removal from an aqueous solution using a UV/Fe3 O4 @Alg-ZnO integrated process. Methods: Response surface methodology (RSM) and a Box-Behnken design were applied using Design-Expert software to optimize the number of samples and simultaneously understand the interactive effects between variables. X-ray diffraction (XRD), a vibrating-sample magnetometer (VSM), field effect scanning electron microscopy (FE-SEM), and Fourier transform infrared (FTIR) analyses were used to check the structural characteristics. The effects of initial catalyst concentration (0.1, 0.3, and 0.5 g/L), initial pollutant concentration (10, 30, and 50 mg/L), contact time (10, 30, and 50 minutes), and pH (3, 7, and 11) on VCM decomposition rate were investigated. Spectrophotometry, total organic carbon (TOC), and GC-MS analyses were used to check the efficiency of the process. Results: In this study, VCM and TOC removal efficiency was 92.64% and 85.38%, respectively, under optimal conditions. The reason for the reduction in the efficiency of the combined UV/Fe3 O4 @Alg-ZnO process in real raw sewage, after activated sludge (13%) and after activated sludge and stabilization ponds (24%), is the high COD, which causes the active radicals produced to be spent on other species instead of the VCM antibiotic. Conclusion: The current study showed that the UV/Fe3 O4 @Alg-ZnO process performs well in removing VCM and TOC. In real wastewater, this efficiency was significantly reduced.