Solar-driven photocatalytic removal of anti-microbial drugs – Comparison of the efficiency of selected photocatalysts

Abstract

The growing interest in the environmental contamination by antibiotics is observed due to their adverse effects on aquatic fauna, formation and spread of antibiotic-resistant bacteria, and antibiotic-resistant genes. Heterogeneous photocatalysis has been found a promising method to remove these recalcitrant micropollutants from the broadly understood aquatic environment. The most efficient functional materials for photocatalytic applications are nano-sized semiconductor oxides. ZnO is recently mentioned to be an alternative to TiO2, a commonly used photocatalyst, for environmental applications, but there is still a lack of information on its operation efficiency, especially in more complex matrices. This study aimed to compare the efficiency of TiO2-P25 and ZnO in the removal of selected veterinary sulfonamides (SAs), namely: sulfadiazine (SDZ), sulfamethoxazole (SMX), and sulfamethazine (SMT) from distilled water (DW), river water (RW), and municipal wastewater effluent (MWWE). TiO2-P25 has been found the most efficient photocatalyst to remove target SAs from DW, while in the case of RW and MWWE ZnO was more efficient in the degradation of studied antibiotics. The removal efficiency of the studied SAs decreased in the following order: SMT>SDZ>SMX. Doubling the photocatalysts concentration increased the efficiency of SAs degradation, but the final effect depends on the complexity of the matrix used.