不同离子强度下蛋白质在PVDF膜面吸附行为评价

Evaluation on adsorption behaviour of protein on PVDF membrane surface under different ionic strengths

摘要:

为考察不同离子强度下牛血清蛋白（BSA）在聚偏氟乙烯（PVDF）膜面的吸附行为及吸附层结构特征，使用耗散型石英晶体微天平（QCM-D）结合自制的PVDF膜片，综合膜污染及膜性能恢复实验，解析离子强度对超滤膜蛋白质污染的影响机理.结果表明：离子强度由0增加到1 mmol/L时，分子间静电排斥力的减弱增强了BSA在PVDF表面的吸附量，膜面形成刚性密实的BSA吸附层，膜污染加剧；相反，离子强度增大到10及100 mmol/L时，水合排斥力逐渐增强，有效减小PVDF-BSA、BSA-BSA间的相互作用力，致使BSA在PVDF表面的吸附量减小，形成松散柔软的BSA吸附层，膜污染大幅度减缓，膜通量恢复率有效提升.

Abstract:

To investigate the deposition and adsorption behavior of BSA on the PVDF surface and the structure of the BSA adsorption layers over a range of ionic strengths, a quartz crystal microbalance with dissipation monitoring (QCM-D) combined with a self-made PVDF-coated sensor crystal was used in this study. These results were combined with those of fouling experiments and the flux recovery rate (at corresponding ionic strengths) to obtain visual insight into the effect of ionic strength on membrane BSA fouling behavior.Results show that when the ionic strength increased from 0 to 1 mmol/L, the adsorption amount of BSA on PVDF surface was increased, and a denser and more compact BSA layer was formed, accompanied by the enhancement of membrane fouling, which was mainly attributed to the decrease of electrostatic repulsion forces. But on the contrary, when ionic strength increased to 10 and 100 mmol/L, the PVDF-BSA and BSA-BSA interaction forces are weakened due to an increase in the hydration repulsion force, which results a decrease in adsorption amount of BSA on PVDF surface, a more nonrigid and soft BSA layer was formed, and membrane fouling decreased significantly. Moreover, the flux recovery rate was increase significantly at high ionic strength.