Preparation of microfiltration membrane supports using coarse alumina grains coated by nano TiO2 as raw materials

To increase the mixing uniformity of coarse alumina grains with a small amount of nano TiO2 particles, TiO2 particles were prepared on the surface of coarse Al2O3 grains by in-situ hydrolysis of TiCl4. The coated coarse Al2O3 powder was used to prepare microfiltration membranes supports. The effects of TiO2 content and sintering temperatures on the bending strength, porosity and pore size distribution of the obtained supports were studied. The results show that the melted nano TiO2 grains locate mainly at the neck of Al2O3 grains, which increases the bending strength of the support by increases the neck area. However, the bending strength is weakened if the TiO2 content is excessive. No aggregated nano TiO2 grainsare found. The resulting supports sintered at 1650 °C for 2 h yields a bending strength of 55.4 MPa, a porosity of 38% with a mean pore size of 8.0 μm.