Photocatalytic degradation of antibiotics in water using metal ion@TiO2/HNTs under visible light

TiO2/HNTs were modified by metal ions with the impregnation method. The as-prepared photocatalysts were characterized by transmission electron microscopy, X-ray diffraction, UV-vis diffuse reflectance spectra (UV-vis DRS), and inductively coupled plasma-atomic (optical) emission spectrometry (ICP-AES). The results demonstrated that TiO2/HNTs were successfully synthesized, and anatase TiO2 was formed after calcination. Moreover, after modification, the as-prepared TiO2/HNTs still kept crystalline structure. Furthermore, a red-shift was obviously observed fromUV-vis DRS, and the band gap energy was narrowed. ICP-AES proved that compared with TiO2/HNTs, metal ions were existed in metal ion@TiO2/HNTs. The photocatalytic activity was studied by the degradation of antibiotics aqueous solution under the visible light irradiation. The results showed that Fe3+@TiO2/HNTs had the strong ability to degrade tetracycline, and the optimum adding concentration of Fe3+ was 0.2 g/L. In addition, the degradation effect of tetracycline was better. The photodegradation rate of 40 mg L-1 tetracycline simulated wastewater could reach 76.54%. The binary system was also investigated, which showed that the degradation rate of co-doped TiO2/HNTs was lower than Fe3+@TiO2/HNTs.