To analyze the effect of protein electrical property to hydration in ultrafiltration

the characteristics of the interaction forces of PVDF-BSA and BSA-BSA (Bovine Serum Albumin) changing with different ionic strengths were separately investigated

as BSA was positively

neutrally and negatively charged. In accordance with the potential variation of Zeta

the mechanism of how the protein electrical property affected hydration was illustrated. When BSA was positively charged

the interaction force increased with the increase of ionic strength

mainly due to that the positively charged BSA could not trigger hydration

and electrostatic force was the main factor controlling membrane fouling. When BSA was neutrally and negatively charged

a large number of hydrated cations adsorbed and accumulated on membrane surfaces of BSA and PVDF

and the increase of the ionic strength would trigger the repelling force of PVDF-BSA and BSA-BSA

and hence the membrane fouling was reduced remarkably. In addition

the hydration phenomenon was more easily observed in BSA isoelectric point