A novel way to fabricate tubular porous mullite membrane supports by TBA-based freezing casting method

Porous tubular mullite supports with gradient unidirectional aligned pores were successfully fabricated by TBA-based freezing casting method. The effects of freezing temperature, solids loading and particle size distribution of mullite powders on the microstructure and properties of the supports were investigated extensively. The results show that the pore size, porosity and compressive strength of the supports can be effectively adjusted by controlling the parameters. Both the results of microstructure observations and properties testing indicate that the pore channel size increases along the freezing direction, accompanied by the changes of pore structure from homogeneous near the freezing medium to unidirectional away from the freezing medium. The pore channel size decreases significantly with increasing solids loading, decreasing freezing temperature and reducing the particle size. The porosity also decreases with increases of solids loading and freezing temperature, as well as reduces of the particle size, while the compressive strength increases.