Fabrication of mesoporous titania–zirconia composite membranes based on nanoparticles improved hydrosol

A novel method for the fabrication of mesoporous titania–zirconia (TiO₂[Formula presented]₂) composite membranes was successfully developed based on nanoparticles (NPs) improved hydrosol. ZrO₂ hydrosols were synthesized through a straightforward sol–gel route using zirconium oxychloride. Compared to the polymeric sol route, this method was found to be more environmentally friendly because organic solvent was not required. Further, highly hydrophilic TiO₂ NPs of 10–20 nm were well dispersed in the sol and effectively reduced the sol infiltrating into the channels of the support layer by a “bridging” effect. After a rapid evaporation process, a mixed matrix gel was formed on the surface of the support. The dynamic mechanical analysis results showed that the toughness and stiffness of the gel were significantly strengthened, which was beneficial to reduce the risk of membrane cracking. So, an integrated, crack-free mesoporous TiO₂[Formula presented]₂ composite membrane was obtained by directly coating and sintering the mixture on a macroporous support. It showed that the composite membrane delivered better separation performance though the filtration test. The water flux, molecular weight cutoff, and average pore size of the synthesized membrane were 60 L m⁻² h⁻¹ bar⁻¹, 4704 Da, and 3.5 nm, respectively.