溶液对蛋白质污染膜的清洗效果分析

采用牛血清蛋白（BSA）代表有机物，自行开发了聚偏氟乙烯（PVDF）膜片，结合耗散型石英晶体微天平（QCM-D），考察不同NaCl浓度条件下BSA在PVDF膜面的微观解吸行为及吸附层结构特征；并使用原子力显微镜测定相应离子条件下与膜污染行为相关的微观作用力大小，综合膜性能恢复实验，解析NaCl溶液对有机物污染膜的清洗机理. 结果表明：随着NaCl离子浓度的从1增加到300 mmol·L-1，PVDF与羧基官能团之间的相互作用力逐渐减小，BSA污染层松散度逐渐增大；同时引入大量的水合Na+离子进入BSA污染层内部，破坏BSA污染层内部的静电吸引力和氢键，进而破坏吸附层结构，伴随着BSA污染膜的通量恢复率随着NaCl离子浓度的增加而大幅度提高。

NaCl cleaning of organic-fouled ultrafiltration membrane

Bovine serum albumin (BSA) was used as a model organic foulant to further unravel the mechanisms of cleaning organic-fouled membranes by concentrated salt solutions. The desorption behavior of BSA on the membrane surface and the structure of the BSA adsorbed layers at corresponding salt concentration were investigated by quartz crystal microbalance with dissipation monitoring (QCM-D) combined with a self-made polyvinylidene fluoride (PVDF)-coated sensor. The interaction forces related to membrane fouling were measured by atomic force microscopy. Flux recovery rates were established for corresponding fouled membranes. The results indicate that when the salt concentration increased from 1 to 300 mmol·L-1, the interaction forces between PVDF membrane and carboxyl group decreased significantly, resulting in the formation of a denser BSA layer. Moreover, a large amount of hydrated Na+ cations entered the BSA layer, causing a decrease in the electrostatic attraction and hydrogen bond among BSA molecules, accompanied by the destruction of the BSA layer. Consequently, the flux recovery rate of BSA-fouled membranes increased with decreased salt concentration.