Highly durable zirconium/titanium dioxide–silicon carbide photocatalytic membrane for water and wastewater treatment

Abstract

Photocatalytic membrane reactors offer an effective method for wastewater treatment by coupling the filtration function of the membrane with photocatalytic activity. This study developed a zirconium doped titanium dioxide coated silicon carbide (Zr/TiO2-SiC) photocatalytic membrane, which was activated by an ultraviolet light emitting diode (UV-LED), and optimum conditions for the photocatalytic synthesis and immobilization were established. The photocatalytic membrane was applied to the degrading of genotoxic and carcinogenic rhodamine B as a typical pollutant of textile wastewater. In addition, humic acid was included, as a relatively large molecule compared to the rhodamine B, to evaluate the antifouling properties of the photocatalytic membrane. The design and operating parameters of the zirconium molar ratio, the photocatalyst loading, and the UV-LED irradiance all affected the performance of the photocatalytic membrane. The results showed that at an optimum concentration of 10 %, the zirconium doping improved the photocatalytic activity by over 20 %. There was also an optimum loading after which the photocatalytic activity decreased. A linear correlation was observed between the reaction rate constant and the irradiance, which can be used for future operation optimization. The photocatalytic membrane was studied further to investigate the durability of the photocatalyst particles attached to the membrane surface, and there was little evidence of deterioration in their photocatalytic activity. The photocatalytic membrane exhibited high antifouling properties when filtering a humic acid solution in a custom-made photocatalytic membrane reactor. The results indicated that the photocatalytic membrane developed has strong potential for industrial application.