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 been investigated. Experimental results were analysed in terms of existing membrane filtration model equations and membrane resistance. Flux decay follows the standard blocking model (SBM) assuming that pore volume decreases proportionally to filtrate volume. The actual mechanisms involved in membrane fouling are thought to be related both to the internal and external fouling by macrosolutes. Protein-membrane interactions in the form of protein adsorption produce a protein-membrane ''composite''. The build-up of this also called ''a secondary dynamic membrane'' explains the characteristic rejection profiles.