synthesis of nanostructured titania/zirconia membrane for treatment of textile industries wastewater

nanostructured tio₂/zro₂ composite membranes with varying compositions were obtained by sol–gel technique. the influence of 0-30 mol% zirconia doping on microstructure, water permeability, photocatalytic and physical separation properties, removal of methyl violet of textile industries wastewater and thermal and mechanical stability of titania/zirconia composite membranes was described. firstly, alumina supports were coated with tio₂ intermediate layers using the colloidal sol–gel route. the tio₂/zro₂ composite sols were prepared via a polymeric sol–gel method and dip-coated on tio2 intermediate layer. the samples were characterized by dls, tg-dta, xrd, ftir, bet-bjh, uv-visible, sem, tem and afm. it was shown that zirconia retards the phase transformation of anatase to rutile until at least 700 ^oc. the minimum pore size and maximum surface area have been obtained 1.2 nm and 153 m2/g, respectively that attributed to the sample with 20 mol% zirconia. the mechanical strength of titania membranes was significantly improved by addition of zirconia. the most methyl violet removal efficiency, with and without uv-irradiation, has been obtained 80.8% and 72.6%, respectively that attributed to the sample with 20 mol% zirconia.