Sulfate radical-based advanced oxidation process (SR-AOP) on titania supported mesoporous dendritic silica (TiO2/MDS) for the degradation of carbamazepine and other water pollutants

Abstract

Sulfate radical-based advanced oxidation processes (SR-AOPs) coupled with photocatalysis provide a viable solution for complete degradation of micropollutants pollutants, These micropollutants pose a significant threat to humans and aquatic organisms. In this study, TiO2 supported on mesoporous dendritic silica (TiO2/MDS) was prepared via ultrasonic assisted impregnation method for degradation of carbamazepine and other micropollutants in the presence of persulfate. FT-IR, XRD, BET, FE-SEM/EDS, TEM, PL, UV–Vis DRS, XPS, and electrochemical techniques were employed for characterization. The TiO2/MDS system exhibits an efficient PS activation activity and outstanding CBZ degradation efficiency compared to MDS and TiO2 system. The results also show that CBZ solution could be completely degraded with 1.0 mM PS and 0.5 g/L photocatalyst. The high activity and stability were a result of reduced electron-hole recombination, effective charge separation and transfer, and a longer electron lifetime observed in TiO2/MDS, among others. The MDS as the support also improved the adsorption and proximity of reactants to the TiO2 activity sites in the system. Additionally, the TiO2/MDS/PS/UV system was tested for degradation of amoxicillin, sulfamethoxazole, naproxen, and bisphenol A. Quenching experiments demonstrated that OH•, SO4•-, h+ and O2•- contributed to the overall degradation efficiency. The results undoubtedly illustrate that the TiO2/MDS/persulfate system is an effective system with potential applicability for water treatment.