Patent ID: 8784541

Claim:
A composite-membrane monolith comprising: a cordierite monolith having surfaces with a surface median pore size of from about 1 μm to about 15 μm; and a cordierite-ceramic composite membrane bonded directly to surfaces of the cordierite monolith without any intervening layer between the cordierite monolith and the cordierite-ceramic composite, the cordierite-ceramic composite having membrane surfaces with a membrane median pore size of 0.3 μm or less and with small pores having small-pore sizes from 0.05 μm to 0.1 μm, the membrane median pore size and the small pores providing polymer coatability to the membrane surfaces, wherein: the cordierite-ceramic composite membrane is a composite having a thermal coefficient of expansion approximately equal to the thermal coefficient of expansion of the cordierite monolith and is formed from a cordierite-ceramic composite slip comprising: from 30 wt. % to 90 wt. % cordierite particles having a cordierite median particle size from about 1 μm to about 3 μm and smaller than the surface median pore size; and from 10 wt. % to 70 wt. % ceramic particles other than cordierite particles, the ceramic particles having a ceramic median particle size from about 0.05 μm to about 0.5 μm and smaller than the cordierite median particle size, wherein a weight ratio of the cordierite particles to the ceramic particles in the cordierite-ceramic composite slip is from 9:1 to 3:7.