Considering photocatalytic activity of N/F/S-doped TiO2 thin films in degradation of textile waste under visible and sunlight irradiation

Degradation of azo dyes as textile industry pollutants was investigated by photocatalytic process using F, N and S tri-doped TiO2 thin films immobilized on the glass spheres. Nanocatalyst thin films were successfully prepared via sol-gel dip-coating method. The immobilized TiO2 on the glass spheres were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), diffuse reflectance spectroscopy (DRS) and CHNS analysis. UV-Vis spectroscopy and chemical oxygen demand (COD) have been used in order to evaluate the degradation process. It was found that optimization of fluorine at 5% doping can give rise to the maximum decomposition of 86-100% within 6 h under visible irradiation. Also, according to the COD results, after 6 h, a reduction of the COD value from the azo dye solution was apparently obtained in same condition. The results showed that the synthesized nano-layers have good stability and reproducibility and therefore are potential to be used in various industrial processes.