Dip-coating technique for the manufacture of alumina microfilters using PVA and Na-CMC as binders: a comparative study

α-Alumina microfiltration flat-membranes have been prepared using the dip-coating procedure. The effect of slip concentration (<30 wt.%), coating time and binder type (PVA and Na-CMC) on the thickness, porosity, roughness and effective pore diameter of the membrane layers has been investigated. A new method for the characterization of the membrane layer based on gas permeation has been presented and the pertaining equations derived. The method is applicable if permeability measurements embrace both Knudsen and Poiseuille flow regimes.