本研究選用管式無機薄膜，以連續式掃流過濾系統對蛋白質溶液進行過濾實驗，探討不同操作條件及溶液性質對濾速與薄膜結垢的影響，以尋求提升濾速之操作方式。首先就蛋白質溶液於管式單通道無機薄膜過濾系統之濾速行為，討論操作參數(透膜壓差、濃度、pH值、溶液組成等)對濾速之影響，並定量薄膜結垢之阻力，找出適當之清洗方法。此外，本研究也以阻力串聯模式計算實驗阻力值來觀察結垢之變化，並以滲透壓模式計算理論濾速與實驗濾速之差異。 結果顯示，NaOH溶液可有效清洗移除附著於膜上之BSA結垢，但隨著溶液濃度之增加也需提高NaOH清洗液之濃度。當操作流態為亂流時，增加BSA進料濃度對濾速之影響不大。在BSA與β-cyclodextrin的混合溶液系統中，薄膜對β-cyclodextrin之阻隔率隨溶液pH值不同而有所改變。以5k Da薄膜舉例，當pH=6.87時，β-cyclodextrin之阻隔率高達80%，而當pH=10時，則低於30%之阻隔率，這是因為BSA粒子形成之極化濾餅層緊密度不同所致。因此，選擇適當pH值可將BSA溶液中之小分子進行分離。 阻力計算結果顯示，不同濃度之BSA溶液於膜面上所產生的阻力皆相近且遠小於薄膜阻力，但β-cyclodextrin溶液所產生的阻力則大於薄膜阻力。在雙溶質溶液中，由於BSA於膜面產生的結垢層阻擋了β-cyclodextrin透膜，使孔洞阻塞阻力值下降。以逆滲透模式計算理論濾速發現，理論濾速與實驗濾速趨勢相同但略大於實驗濾速，這可能是因為滲透壓模式只考慮膜面濃度提高對滲透壓所產生之效應而忽略了結垢層對濾速下降之影響使理論濾速較高。 In this study, the inorganic tubular membranes(1000, 5000 MWCO) were employed in a cross-flow filtration system to investigate the effect of operation conditions, solutions and membrane properties on protein solutions filtration. The way for cleaning the membrane fouling were also discussed. The solution fluxes and solute rejection were measured under various operating parameters such as membrane MWCO, transmembrane pressure, pH value and solution composition. In addition, in this work also calculate experimental resistance value with resistance-in-series model and predicting flux of BSA solution with osmotic pressure model which will compare with experiment flux. Experimental results indicate that the NaOH solution could removal the BSA fouling on the membrane and the required concentration of NaOH solution increase as the feed BSA concentration increases. Under the turbulent flow pattern, the increase in BSA concentration just slightly reduces the flux. For BSA and β-cyclodextrin binary solution, the rejection of β-cyclodextrin varies with the pH value. In the case of 5k Da membrane, the rejection of β-cyclodextrin is higher than 80% at pH=6.87 and less than 30% in pH=10. This is due to the fact that the porosity of the polarization layer of BSA on the membrane surface varies with pH value. Therefore, the present membrane can be applied for the separation of small molecule from BSA solution by choosing a suitable pH value. In resistance-in-series model, fouling resistance value in all solution concentration of BSA are almost the same and far smaller than membrane resistance value. But in β-cyclodextrin solution, the values become higher than membrane. When in binary solution, fouling layer form by BSA on membrane surface could reject β-cyclodextrin transmembrane, so that the pore blocked resistance value can be decreased. In osmotic pressure model, the trend of theoretical flux agree with experiment flux but higher than it. This is could be the osmotic pressure model just only to consider the concentration rise in membrane surface but the influence of fouling layer was neglected.
