PVC膜过滤几种典型物质的吸附截留特性研究

Study on adsorption and interception preperties of several typical substances in PVC membrane filtration

采用聚氯乙烯(PVC)微滤膜对糖、脂肪、蛋白类的代表性物质:蔗糖、牛血清蛋白(BSA)、三乙酸甘油酯、L-谷胱甘肽、麦芽糊精进行了过滤实验研究,分析了PVC膜对这些物质的动态吸附及截留特性,讨论了跨膜压差增量(Δp)与累积吸附截留量(q)之间的关系.结果表明,BSA和L-谷胱甘肽在膜上有吸附行为,二者的饱和吸附量分别为47.5μg/cm2和1.0μg/cm^2,且此吸附过程可用准一级动力学方程较好地描述.除三乙酸甘油酯外,其他4种物质在膜上均表现出截留现象,其中麦芽糊精的过滤过程出现2个阶段,4种物质的平衡截留率分别为:麦芽糊精(阶段一)12.7%、麦芽糊精(阶段二)9.7%、蔗糖6.5%、BSA 4.5%和L-谷胱甘肽0.5%;L-谷胱甘肽、麦芽糊精(阶段一)、BSA和蔗糖的污染系数分别为0.052、0.043、0.027、0.009,综合以上两因素,在过滤过程中,麦芽糊精对PVC膜污染最严重,但过滤后期麦芽糊精污染层在膜孔部位发生周期性的形成-坍塌现象,膜污染不再随时间增加,BSA、蔗糖和L-谷胱甘肽、三乙酸甘油酯的污染依次减小.

Sucrose, bovine serum albumin （BSA）, glycerol triacetate, L- glutathione and mahodextrin were filtered as representative materials for sugar, fat and protein by polyvinyl chloride （PVC） membrane in this study. The dynamic adsorption and interception preperties of these five materials by PVC membrane were analyzed. And the relationship between increments of TMP （△p） and cumulative adsorption interception （q） was also discussed. The results showed that the adsorption capacities of BSA and L- glutathione in the membrane were 47.5 μg/cm2 and 1.0 μg/cm2 respectively, and the adsorption process could be described by quasi-first-order kinetic equation. All materials but glycerol triacetate showed a retention phenomenon by the membrane during the filtration process, and two kinds of stages were observed in mahodextrin filtration process. The balance retention rates of maltodextrin, sucrose, BSA and L-glutathione were mahodextrin （stage 1） 12.7%, maltodextrin （stage 2） 9.7%,6.5% ,4.5% and 0. 5% respectively. And the pollution coefficients of L- glutathione, maltodextrin （stage 1）, BSA and sucrose were 0. 052.0. 043.0. 027.0. 009 respectively. Considering the two factors above, maltodextrin is the most serious pollution to PVC membrane in the process of filtration, but the membrane fouling is no longer increasing with time in the late stage of filtration because of the periodic formation-collapse process of contaminated maltodextrin layer at membrane pores. The degree of contamination of the membrane caused by BSA, sucrose, L-glutathione and glycerol triacetate decreased in turn.