膜材結構對蛋白質微過濾反覆操作程序影響之探討

Effect of Membrane Morphology on the Dead-end Microfiltration of Protein Solution during Filtration Cycles

王筱菁(Sherjing Wang)

指導教授 ： 童國倫

中原大學/工學院/化學工程研究所/碩士(2002年)

https://doi.org/10.6840/cycu200200155

摘要

膜過濾是一種相當簡易、省能的物理操作，不牽涉到相的變化及熱能的需求。而在蛋白質微過濾程序中，由蛋白質粒子與膜材間的交互作用所引發的結垢現象，是影響過濾效能的主因。因此，如何選擇適當的膜材是相當重要的課題。本研究之目的在探討薄膜形態及結構對蛋白質微過濾之影響及高孔隙度之PTFE膜做生化分離膜材之應用性。
研究中，我們以牛血清蛋白(BSA) 和酵母菌(Yeast) 混合液為分離對象，比較孔徑相近的PC膜、PES膜和PTFE膜在恆壓(dead-end) 微過濾下的過濾與清洗效果。以粒子堵塞機制理論配合電子顯微鏡觀察膜表面BSA 和Yeast 在不同膜材的結垢型態，分析生物粒子在薄膜微過濾的過濾行為。探討不同操作壓力和泥漿酸鹼值等對各種膜材之影響，再讓每種膜在其最佳條件下進行反覆操作，並比較PTFE膜以何種清洗方式有最佳過濾效果。
由研究結果得知，過濾初期膜材主導過濾行為，到了後期則由濾餅層主導，當泥漿之酸鹼值越接近Yeast之等電點，變形度越低、聚集越少，故形成的濾餅層孔隙度較高，使過濾效果較佳﹔而操作壓力越高固然使濾速越快，但因為生物粒子的變形度高，壓力太大會濾餅層壓縮得更緻密，而急遽增加過濾阻力﹔在反覆操作中，PTFE膜憑藉其高孔隙和耐化性以提供較多孔道讓濾液通過，承受鹼性溶液沖洗膜材使清洗程度最高，因而過濾效果最佳，使用壽命最長。

關鍵字

鐵弗龍薄膜 ； 微過濾 ； 逆洗 ； 反覆操作 ； 生化分離

並列摘要

Membrane separation processes are used for size-based separations with high-throughput but relatively low energy requirements. However, protein fouling, initiated by the interaction between proteins and membranes, is the major reason for the decline of filtration flux in microfiltration. Therefore, how to select a suitable filter membrane is one of the main courses in this field. Purposes of this study are emphasized on the studies of how the membrane morphology and operating conditions will affect the filtration performance and the applicability of porous PTFE membrane in protein microfiltration.
Experiments were performed with the modeled fermentation broth of the mixture of BSA and Yeast particles. Three kinds of microfiltration membranes of PC, PES and PTFE membranes were selected to evaluate how the membrane morphology and operating conditions affect the filtration performance during dead-end microfiltration cycles. The law of blocking was adopted to analyze the effect of membrane morphology and operating conditions on the fouling mechanism. Surface structure of the fouled membrane was examined by using SEM.
Results show that the fouling behavior can be divided into two stages. The initial fouling was due to the blocking of BSA aggregates in the pore of membrane. And the resistance growth in long-term operation was originated from the growth of cake layer and the compression of the deposition layer. Although the PTFE membrane showed a poor initial filtration rate at the first cycle, it kept a lowest fouling rate during each filtration cycles due to its high porosity and chemical inert property for washing by weak base solution.

並列關鍵字

PTFE membrane ； microfiltration ； washing ； bio-separation ； cyclically operation

參考文獻

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