preparation and characterization of nanostructured titania-coated silica microsphere membranes with simultaneous photo-catalytic and water separation treatment applications

In this research, the nanostructured titania-coated silica microsphere (ntcsm) membrane consisting of titania-silica core-shell particles on α–alumina substrate was prepared by dip-coating method. the silica microspheres were synthesized by the stöber method, and the nanostructured titania shell was obtained from a polymeric sol. then, the prepared core-shell particles were deposited on alumina substrates. the samples were characterized by dls, tg-dta, xrd, ftir and sem. the photo-catalytic activity of the ntcsm membranes was evaluated using photo-degradation of methyl orange solution by uv–visible spectrophotometer. in addition, physical separation capability was investigated by filtration experiment based on methyl orange removal from aqueous solution using a membrane setup. the mean particle size of silica microspheres was determined to be around 650 nm, which increased to about 800nm by the deposition of titania nano-particles. after 60 min of uv-irradiation, the dye removal efficiency was determined to be 80% by the membrane. by coupling separation process with photo-catalytic technique, the removal efficiency was improved up to 97%. thus, the ntcsm membranes showed simultaneous photo-degradation and separation capabilities for dye removal from water.