The use of a diatomite–kaolin composite coating to design the pore characteristics of a sintered diatomite membrane

Porous ceramic membranes have lately attracted great interest due to their outstanding thermal and chemical stability. In this paper, we report the results of our efforts to determine whether we could prepare a diatomite–kaolin composite coating to be deposited over a sintered diatomite support layer that could reduce the largest pore size of the sintered diatomite membrane while retaining an acceptable level of permeability. We determined under what conditions such a composite coating over a support layer could be prepared without the generation of micro-cracks during drying and sintering. The pore characteristics of the sintered diatomite membranes were studied by scanning electron microscopy and capillary flow porosimetry.