以平板掃流式超過濾系統，探討不同溶質(BSA、Dextran T70、β-cyclodextrin) 溶液於不同親疏水性薄膜(PES膜、RCA膜)，及在不同操作參數(液體速度、pH值、透膜壓差)下，濾速、阻隔率、過濾阻力以及雙溶質溶液分離效率之變化。 實驗結果顯示，溶質溶液與過濾薄膜之親疏水性質相異時，粒子與膜面有一排斥作用力存在，如RCA膜過濾BSA溶液時，溶質不易在膜面上形成結垢，因此濾速較高。此時增加掃流速度，對濾速的提升較為有限。當溶液之pH值遠離等電點，除粒子與膜面有排斥力外，粒子與粒子間也有排斥力，導致結垢層較薄較鬆散，濾速較高。在BSA與β-cyclodextrin雙溶質溶液中，其濾速較純BSA溶液來得低，此因部分β-cyclodextrin進入薄膜孔道形成內部結垢所致。使用PES膜時，BSA溶質之親疏水性與薄膜一致時，則有一吸引力導致結垢嚴重，小分子β-cyclodextrin的穿透率較低，且隨著壓力增加結垢越緊密，造成分離效率越低。 In this study, polymer membranes were employed in a cross-flow ultrafiltration system to investigate the effects of solution compositions and membrane properties on filtration. The solution fluxes, solute rejections and filtration resistances were discussed under various operating parameters such as liquid velocity, pH value and transmembrane pressure. Experimental results indicate that the difference in the hydrophobicity between the feed solution and membrane generates an exclusion force to retard the formation of fouling layer on the membrane surface. Such as the case of filtration of BSA solution by the RCA membrane, a high permeate flux is achieved due to the low fouling propensity. When the pH value is far away the BSA isoelectric point, the porosity of BSA deposited layer is high due to exclusion between the BSA molecules and results in high flux. In the binary solutes system, cause by the internal fouling of β-cyclodextrin, the flux of solution containing β-cyclodextrin is lower than that of pure BSA solution. On the other, BSA molecules have strong fouling propensity to PES membrane, the transmission of β-cyclodextrin is lowered due to the compact BSA deposited layer and becomes lower as the applied pressure increases that will reduce the separation selectivity.
