超滤过程中蛋白质带电性对水合作用的影响机制

为解析超滤过程蛋白质带电性能对水合作用力的影响机制,在牛血清蛋白(BSA)带正电、中性及负电条件下,分别考察PVDF-BSA及BSA-BSA之间的相互作用力随离子强度的变化特征,结合相应条件下BSA的Zeta电位变化特征,探讨超滤过程蛋白质带电性能对水合作用力的影响机制.结果证实BSA带电性能是影响水合作用力的关键因素.在BSA带正电条件下,作用力随离子强度的增大而增大,主要是因为BSA带正电时无水合作用存在,静电作用力的变化是控制膜污染的主要因素.在BSA电中性及负电条件下,BSA及PVDF膜面吸附累积大量的水合阳离子,随离子强度的增大,有效触发PVDF-BSA及BSA-BSA之间的水合排斥力,进而大幅度减缓膜污染;且在BSA等电点更容易观察到水合作用现象.

Effect mechanism of protein electrical property to hydration in ultrafiltration

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.