Development of TiO2 ultrafiltration membranes using nanoparticle slurry-based dip coating

TiO₂ ultrafiltration (UF) membranes are promising for environmental applications such as wastewater filtration and photocatalysis. Herein, dip coating of Al₂O₃ microfiltration (MF) membranes with a TiO₂ nanoparticle (NP) slurry is proposed as an alternative to the conventional, laborious sol–gel method to prepare these membranes. The dispersion of the NPs in the slurry was optimized using chemical and mechanical treatments. The effect of the sintering temperature on the pore size distribution was evaluated. The slurry was stabilized by 2.3 wt% Darvan CN at pH 8.5. Small milling ball sizes improved the dispersion and reduced the agglomerate size. The optimized slurry was used to produce a 3.3 µm-thick TiO₂ UF layer. Sintering at 700 ℃ yielded pore sizes up to 50 nm and 26 nm (Hg porosity and molecular weight cut-off measurements, respectively). These findings demonstrate how dip coating using a TiO₂ NP slurry facilitates the development of TiO₂ UF membranes.