Preparation of supported photocatalytic membrane from mesoporous titania spheres for humic acid removal from wastewater

Alumina-supported titania photocatalytic membrane was prepared by coating of TiO2 spheres to remove humic acid from wastewater via photocatalytic oxidation degradation combined with physical filtration. TiO2 spheres with an average diameter of about 225 nm were synthesized by hydrothermal crystallization of titanium glycolate spheres with an average diameter of 280 nm. The X-ray diffraction results indicated that the resulting TiO2 spheres consisted of anatase and brookite phases. The transmission electron microscopy images showed that the TiO2 spheres consisted of small crystallites with sizes of about 10 nm and confirmed their crystal structures. The nitrogen sorption experiments indicated that the TiO2 spheres were mesoporous and had an average pore diameter of 10.2 nm and a Brunauer, Emmet and Teller surface of 86.7 m2/g. The alumina-supported TiO2 sphere membrane, which was prepared by 10% TiO2 coating solution, exhibited excellent photocatalytic property; in particular, it degraded 58% of humic acid after 240-min UV light irradiation. It also removed 92% of humic acid in filtration process and with aid of 15-min UV light irradiation interval throughout 3 h of filtration process. In addition, the permeate flux of the TiO2 membrane was improved because of reduced membrane fouling.