MECHANISMS GOVERNING PERMEATE FLUX AND PROTEIN REJECTION IN THE MICROFILTRATION OF BEER WITH A CYCLOPORE MEMBRANE

Mechanisms which determine permeate flux and protein rejection for the microfiltration of a clarified beer using a Cyclopore membrane have b een investigated. Experimental results were analysed in terms of exist ing membrane filtration model equations and membrane resistance. Flux decay follows the standard blocking model (SBM) assuming that pore vol ume decreases proportionally to filtrate volume. The actual mechanisms involved in membrane fouling are thought to be related both to the in ternal and external fouling by macrosolutes. Protein-membrane interact ions in the form of protein adsorption produce a protein-membrane ''co mposite''. The build-up of this also called ''a secondary dynamic memb rane'' explains the characteristic rejection profiles.