Sol-gel synthesis of nanostructured titania-silica mesoporous membranes with photo-degradation and physical separation capacities for water purification

The effect of silica addition on the photocatalytic and separation properties of mesoporous titania-silica membranes was investigated. Macroporous α-alumina support was used as substrate, and intermediate layer was obtained by deposition and calcination of the colloidal titania sol on the substrate. Then, titania and titania-5% silica polymeric sols were prepared for deposition on the interlayer as membrane top layer. The samples were characterized by DLS, TG-DTA, XRD, FTIR, BET, FESEM, TEM and AFM. The photocatalytic capability of the membranes was evaluated using methyl orange photo-degradation. The mesoporous composite membrane was prepared with the average pore size of 3.94 nm. The dye removal efficiency of the titania-silica membrane has been determined to be 63% after 60 min UV-irradiation. By coupling separation process with photocatalytic technique, the removal efficiency was improved up to 94%. The synthesized titania-silica membrane showed a great potential due to its multifunctional capability for water treatment.