TiO2/Zeolite Composites for SMX Degradation under UV Irradiation

Sulfamethoxazole (SMX) is a common antibiotic that is considered an emerging pollutant of water bodies, as it is toxic for various aquatic species. TiO2-based photocatalysis is a promising method for SMX degradation in water. In this work, TiO2/zeolite (Z-45 loaded with TiO2 labeled as TZ and ZSM-5 loaded with TiO2 labeled as TZSM) composites were prepared by mechanical mixing and liquid impregnation methods, and the photocatalytic performance of these composites (200 mg·L−1) was investigated toward the degradation of SMX (30 mg·L−1) in water under UV light (365 nm). The pseudo-first-order reaction rate constant of the TZSM1450 composite was 0.501 min−1, which was 2.08 times higher than that of TiO2 (k = 0.241 min−1). Complete SMX degradation was observed in 10 min using the UV/TZSM1450 system. The mineralization ability in terms of total organic carbon (TOC) removal was also assessed for all of the prepared composites. The results showed that 65% and 67% of SMX could be mineralized within 120 min of photocatalytic reaction by TZSM2600 and TZSM1450, respectively. The presence of Cl− and CO32− anions inhibited the degradation of SMX, while the presence of NO3− had almost no effect on the degradation efficiency of the UV/TZSM1450 system. The electrical energy per order estimated for the prepared composites was in the range of 68.53–946.48 kWh m−3 order−1. The results obtained revealed that the TZSM1450 composite shows promising potential as a photocatalyst for both the degradation and mineralization of SMX.