Enhanced photocatalytic activity of Fe-, S- and N-codoped TiO₂ for sulfadiazine degradation

The composite material based on N-, S-, and Fe-doped TiO₂ (NSFe-TiO₂) synthesized by wet impregnation was used as a photocatalyst to rapidly degrade sulfadiazine. The photocatalytic degradation behavior and mechanism of sulfadiazine on NSFe-TiO₂ were investigated for revealing the role of degradation under ultraviolet light. The results showed that compared with TiO₂, NSFe-TiO₂ markedly improved the efficiency in photocatalytic degradation of sulfadiazine: more than 90% of sulfadiazine could be removed within 120 min by NSFe-TiO₂ dosage of 20 mg L^-1. The process conformed to first-order reaction kinetics model. The parameters such as loaded amount of NSFe-TiO₂, solution pH value, humic acid concentration and recycle numbers on removal efficiency were also studied. Compared to neutral and alkaline conditions, acidic condition was not conducive to the photocatalysis. HA, Ca²⁺, Cu²⁺ and Zn²⁺ in the actual water body had mild inhibition on sulfadiazine degradation in UV/NSFe-TiO₂ system. Fragments screened by high-resolution mass spectrometry were conducted to explore the oxidation mechanism and pathways of sulfadiazine degradation. On the whole, UV/NSFe-TiO₂ photocatalysis has a good effect on sulfadiazine removal.

The online version contains supplementary material available at 10.1007/s13762-023-04771-6.