Characterization of MF/UF Membranes
The microfiltration (MF)/ultrafiltration (UF) membranes may be characterized in many different ways, depending not only on the parameter of interest, but also on the purpose for which the characterization information is needed. Most of the MF/UF membrane characterization deals with the quantitative description of the membrane pore space. Traditionally, rejection characteristics of UF membranes have been determined by single-solute protein ultrafiltration experiments. The permporometry characterization requires a clean, dry UF membrane. For both membrane types, corresponding thermoporometry data were in good qualitative agreement with the gas adsorption/desorption results. Gas-liquid porosimetry evolved from the bubble point test, in parallel with the analogous technique of liquid-liquid porosimetry. Gas-liquid porosimetry also generates a "breakthrough curve". The commonly used cylindrical pore model, applicable to such special-type membranes, assumes that pores have a form of parallel, nonintersecting, cylindrical capillaries. A membrane throughput test represents a very practical characterization technique for MF membranes.