Liquid-phase non-thermal plasma-prepared N-doped TiO2 for azo dye degradation with the catalyst separation system by ceramic membranes

摘要

This study strived to improve the photocatalytic activity by using liquid-phase non-thermalnplasma (LPNTP) technology for preparing N-doping TiO2 as well as to separate/recover thenN-dope TiO2 particles by using ceramic ultrafiltration membrane process. The yellow colornN-doped TiO2 photocatalysts, obtained through the LPNTP process, were characterized withnUV–Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysisn(ESCA). The UV–Vis spectrum of N-doped TiO2 showed that the absorption band was shiftednto 439nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectranshowed that the peak positions and the crystal structure remained unchanged as anatasenafter plasma-treating at 13.5W for 40 min. The photocatalytic activity of N-doped TiO2 wasnevaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours inna continuous-flow photocatalytic system. For membrane separation/recover system,nthe recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min,nand the result indicated that the photocatalyst was able to be separated/recovered completely.