Simple fabrication of a photocatalyst hybridized porous chitosan-based antifouling active filter under visible light

To induce the antifouling activity of a chitosan filter of mask type under visible light such as daylight or xenon-lamp, Cr-doped TiO2 was synthesized and developed into Cr-doped TiO2 hybridized porous chitosan structures. We examined various properties such as morphology, crystallization intensity, mechanical strength, component analysis, water contact angle, and degradation efficiency of methylene blue as a measure of photocatalytic activity under xenon-lamp. We ascertained that it was optimal to combine 3 % Cr-doped TiO2, 1 % chitosan (molecular weight <1000 kDa), and an ultrasonic dispersing method to achieve good mechanical strength and optimal porous structure. Anatase Cr-doped TiO2 was successfully obtained after sintering at 300 °C for 5 h. With the exception of 6 % Cr-doped TiO2, the porosity of these hybridized porous chitosan-based filters increased with an increase in Cr-doped TiO2 concentration. Furthermore, these filters showed a methylene blue degradation efficiency of 86 %. These results indicate that Cr-doped TiO2 hybridized porous chitosan-based filters can be widely used as smart filters for self-cleaning and antifouling applications.