Waste-to-resource preparation of a porous ceramic membrane support featuring elongated mullite whiskers with enhanced porosity and permeance

Different from traditional particle packing structure, a porous structure of ceramic membrane support was fabricated, featuring elongated mullite whiskers with enhanced porosity, permeance and sufficient mechanical strength. The effect of additives (MoO3 and AlF3) and sintering procedure on open porosity, mechanical properties, pore size distribution, micro-structure, phase structure, and permeance of the membrane supports was characterized in detail. The introduction of MoO3 and AlF3 promoted formation of a porous whisker-interlocked structure, which effectively improved open porosity and permeance. A mullite membrane support containing 5 wt.% MoO3 and 4 wt.% AlF3 exhibited an open porosity as high as 48.6 ± 0.5%, a mechanical strength of 81.2 ± 3.2 MPa at 1200 °C, and the value of permeance was higher than the membrane without any additives. Such enhancements in porosity and permeance, with sufficient mechanical strength, were a result of tortuosity decrease due to a porous structure of interlocked mullite whiskers.