Studies of Protein Absorption and Fouling Behavior on Amphoteric Charged Polypropylene Microfiltration Membrane

Abstract

To improve the antifouling property of PP membrane, a series of amphoteric charged membranes was prepared by the introduction of cysteine on polypropylene membrane. The modified membrane presents higher water flux than original membrane due to the improved hydrophilicity. It was proved by zeta potential that modified membrane inherited the amphoteric characteristic from cysteine. The isoelectric point of modified membranes are at pH 7.2 and 6.5 for 7.6% and 16.1% grafted membranes respectively. Due to the amphoteric characteristic of both modified membrane and BSA, electrical repulsion exsists among grafting chains and BSA in acid and alkaline solution. As a result, modified membranes have much lower adsorption amount of BSA than original PP membrane. Moreover, modified membranes show obvious antifouling property to BSA, due to the improved hydrophilicity of membrane and the electrical repulsion between BSA and membrane. Therefore, the amphoteric charged membranes modified by cysteine show great potential to resist protein fouling in a wide range of pH.