Chemically Modified Ultrafiltration Membranes for Enzyme Fixation
Ultrafiltration is a widely used and well established separation process in which asymmetric porous membranes are commonly applied. Many a textbook is listing the wide array of different applications in various branches of industry and gives extensive advice on membrane preparation and on the pros and cons of the various membrane polymers (Cheryan, 1986; Staude, 1992). Mostly, the synthetic polymers used as membrane materials are hydrophobic from their origin. Generally, this circumstance does not effect seriously the application of these types of membranes. Sometimes, however, intermolecular interactions between pol-ymer and substrate cause special problems that are referred to as fouling. Such interactions are exerted by hydrophobic forces yielding adsorption that can effectively be diminished by a chemical modification of the membrane material. This is best performed by introducing ionogenic substituents to the polymer. Due to this the hydrophobic character of the polymer becomes smaller and the adsorption is less pronounced. Such reactions sometimes cause a change to hydrophilic membranes. In any case such a chemical reaction presupposes that the polymer backbone remains intact, otherwise the polymer would lose its film-forming properties. Introducing ionogenic groups offers an additional advantage. A membrane bearing fixed charges can reject or attract solutes according to the respective sign of the matter to be ultrafiltered.
KeywordsEffectiveness Factor Sulfonic Acid Group Ultrafiltration Membrane Upstream Side Ionogenic Group
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- Barker, S.A., and Burns, R.F., 1973, Reaktor separators incorporating membrane bound enzymes, Chem. Ind. 18:801.Google Scholar
- Cheryan, M., 1986, “Ultrafiltration Handbook”, Technomic Publishing Comp. Inc. Lancaster, PA.Google Scholar
- Hartmeier, W., 1986, “Immobilisierte Biokatalysatoren”, Springer Verlag, Berlin, Heidelberg, New York, Tokio.Google Scholar
- Rodemann, K. and Staude, E., 1995, Preparation and characterization of porous polysulfone membranes with spacer-bonded N-containing groups, J. Appl. Polym. Sci. in press.Google Scholar
- Staude, E.. 1992, “Membranen und Membranprozesse”,VCH, Weinheim, New York, Basel, Cambridge.Google Scholar