Porous ceramic disks for filtering application

I am seeking porous ceramic disks to test for my company\\\'s filtering application. We are interested in disks approximately 5cm in diameter and thicknesses approximately 0.5 cm in thickness. As we are in early tests, we can be flexible with size and shape of these discs. We seek porosity of the ceramics with median pore size ranging from 50nm to 500nm. We are flexible with ceramic material.
Do you have any ceramics we could try for our application? Any thoughts would be great.