- 學位論文
不同含水量、厚度之細菌纖維素用以油水分離與其過濾特性之研究
Oil/Water Separation by Bacterial Cellulose with Different Water Holding Capacity and Thickness
摘要
由於細菌纖維素其內部具有獨特的 3D 網狀結構和許多特色如:高親水性、可食用，因此常被應用於食品、生醫材料等應用。近年來亦有文獻指出 BC 可被作為油水過濾膜或膠囊外殼之潛力。 先前實驗室訂立了量測細菌纖維素之含水量準則(藍, 2017)，能夠精確的定量出含水量，隨後實驗室的另一研究(范, 2020)，分別以不同起始培養基 pH 值與不同的碳源培養出不同產量的細菌纖維素，並發現產量與含水量為一反向關係，可能顯示其結構緊密程度不同所致。故本研究利用不同含水量之細菌纖維素過濾油水乳液的方式來了解細菌纖維素與對油的阻抗性及結構差異並分析其過濾特性，結果發現不同含水量之細菌纖維素皆對油有良好的阻抗性，對油的排斥係數(Rejection coefficient, R)皆大於 99%。 進一步分析顯示了薄膜之含水量(θ)、厚度(L)的改變對過濾比阻(Specific resistance, α)影響不明顯；而薄膜阻力(Resistance of membrane, Rm)對含水量呈現反向關係，但對厚度呈現正向關係，顯示了含水量越低的細菌纖維素其內部纖維結構較密，因此其薄膜阻力較高；而厚度的增加也會使得細菌纖維素對於流體的阻力增加。根據實驗結果將細菌纖維素的含水量、厚度與薄膜阻力(Rm)做連結，可整理出薄膜阻力和含水量與厚度的關係式:Rm = 1.95 × 10^(16) × θ^(−0.7) × L，往後可根據已知的細菌纖維素含水量及厚度來評估其薄膜阻力及預測不同操作條件下的過濾通量曲線。
並列摘要
Bacterial cellulose (BC) has an unique 3D network structure and many characteristics such as high hydrophilicity and edibility. It is often used in the field of food, biomedical materials and many others. In recent years, there have been some studies pointing out that BC has the potential to be used as an oil-water filtration membrane and capsule shell. To estimate water holding capacity (WHC) of BC accurately, a draining method previosuly was developed in our lab. The culture medium initial pH value is set at 4.0, 5.5, 7.0. Glucose, glycerol, ethanol, and a mixture of glucose and glycerol are added in medium as the carbon source. Futher study found a reverse relation between yield and WHC of the BC by various cultivation condition, perhaps due to structural compactness. This study aims to investigate if BC of different WHC could separate oil from water and characterize its performance. The experimental results indicated that the bacterial cellulose with different WHC could separated oil from water with >99% rejection coefficient (R). Futher analysis of experiment at results showed that water holding capacity (θ) and thickness (L) of the BC did not affect the specific resistance (α). On the other hand, membrane resistance (Rm), because difference internal structure, the expression of Rm = 1.95 × 10^(16) × θ^(−0.7) × L. Thus the membrane resistance of BC can be estimated accordingly.