Porous asymmetric microfiltration membranes shaped by combined alumina freeze and tape casting

An assembled asymmetric alumina microfiltration membrane with high performance was prepared by combining freeze and tape casting techniques followed by two sintering steps. Freeze casting was used for manufacturing of the porous support layer with a highly interconnected pore network. Tape casting was applied on the top layer to form a pre-membrane with smaller pore size and controlled thickness, which was set on the sintered support. Morphology influences were investigated for different solid loadings, additives content and the assembled layer membrane structures. No delamination among the layers was observed. The assembled ceramic membrane had an average pore size between 30 and 50 m together with a top surface layer around 0.35 m, which is suitable to the microfiltration separation process. Porosity in the range of 26-50 % and water flux of 11-32 m(3) m(-2) h(-1) bar(-1) were reached for samples prepared with two sintering steps at 1600 and 1300 degrees C for 2 h.