MODIFICATION OF CERAMIC MEMBRANE SURFACES USING PHOSPHORIC-ACID AND ALKYL PHOSPHONIC-ACIDS AND ITS EFFECTS ON ULTRAFILTRATION OF BSA PROTEIN

Surface properties are known to play an important role in ultrafiltrat ion processes. Phosphoric acid and alkyl phosphonic acid were linked t o the surface of titania and zirconia membranes to modify the interact ions between the membrane and the molecules in the bulk solution. The adsorption mode of the phosphate derivatives was characterised by dire ct analysis using infrared spectroscopy. BSA filtrations were performe d using an ultrafiltration titania membrane with different surface mod ifications. The contributions of both the electrostatic interactions b etween the protein and the membrane surface, and the competitive react ions between BSA and ions in solution, were separated. The competitive reactions of BSA and phosphate ions on the titania surface have to be managed to reach the maximum adsorption of phosphate before the prote in filtration. Increase in membrane hydrophobicity also improves BSA r ejection.