Zirconia and titania composite membranes for liquid phase separation: preparation and characterization

Crack-free tubular TiO2/ZrO2 composite ceramic membranes on ZrO2 supports have been successfully synthesized from colloidal titania sols by the sol-gel technique. The pore sizes of the prepared membrane were mainly controlled by the sol properties and the calcination conditions. The influence of different parameters such as additives and solvents on the hydrolysis and polycondensation properties of the sols was studied by DTA-TG and viscosity measurements. The TiO2/ZrO2 composite ceramic membranes were characterized by X-ray diffraction and scanning electron microscopy. Composite membrane permeability and rejection properties were also investigated. The results proved that the range of composite membrane flux and retention could be controlled by controlling the amount of polyethylene glycol (PEG). PEG in titania sol systems was suitable for use as an organic additive to fabricate crack-free composite membranes. The larger the amount of PEG added to the precursor solution, the larger the size and number of pores produced in the prepared membranes when the PEG was completely combusted during heat-treatment. By controlling the amount of PEG added to the precursor solution, TiO2/ZrO2 composite ceramic membranes with different pore sizes were prepared, which can be used in photocatalytic membrane reactors and applied in liquid-liquid or liquid-solid separation in future research.