Floating TiO 2 /expanded perlite prepared for degradation of sulphadiazine and sulphamethoxazole

Photocatalysis treatment is a promising technology to eliminate antibiotic pollution. In this study, a floating TiO2/expanded perlite (TiO2/EP) catalyst was successfully prepared using a simple dip-coating method. The photocatalytic degradation effects of sulphadiazine (SDZ) and sulphamethoxazole (SMZ) were investigated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements demonstrated that TiO2 has been immobilised on the surface of EP. The TiO2/EP with TiO2 dip-coating three layers displayed the best degradation effect of SDZ and SMZ and the loading amount of TiO2 was 20wt%. The photocatalytic degradation rates of SDZ and SMZ were above in the TiO2/EP+UV system reached over 92% within 75 min, and followed a pseudo-first-order kinetic model. Low initial concentration (<10 mg L−1) and neutral pH water environment were found to be favourable for the photocatalytic degradation of SDZ and SMZ. Additionally, electrolyte ions (SO42- and Cl−) and humic acid (HAc) showed inhibitory effects on the degradation of SDZ and SMZ. However, HCO3− inhibited the degradation of SDZ and SMZ at low concentration and had the opposite effect at high concentrations. This study provides valuable data for the designing of composite photocatalysts for efficient removal of SDZ and SMZ in real water systems.