利用奈米過濾分離葡萄糖和氯化鈣混合溶液之研究

A study on separating the glucose and calcium chloride solution by using nanofiltration

鄭佩欣(Pei-Xin Zheng)

指導教授 ： 莊清榮

中原大學/工學院/化學工程研究所/碩士(2015年)

https://doi.org/10.6840/cycu201500563

摘要

在工業製程中，當面臨含中性溶質及鹽類離子之混合溶液的選擇性分離，一般以薄膜過濾如NF為主，然而鹽類會改變膜材電性和中性溶質之水合半徑，進而影響分離純化之效能。因此，本研究以NF270、DK及GE等三種商業的奈米薄膜進行葡萄糖和氯化鈣溶液之分離，分析篩分作用和薄膜電性對分離效能之影響。除了比較單一溶質及混合溶液之濾速及阻擋率的變化，也探討不同氯化鈣濃度、操作壓力及pH值等對分離效能的影響，並於垂直膜面兩端施加電場，分析施加電場後之分離效果。
實驗結果顯示NF270薄膜雖有較高之通量，但其孔徑小於葡萄糖及鈣離子之Stokes diameter，於本研究選用之濃度與pH條件下，鈣離子與葡萄糖之阻擋率皆有85%以上，無法達到兩溶質選擇性分離的效果。
而其他兩種薄膜之結果如下：以DK薄膜操作時，混合溶液之兩溶質阻擋率均較單一溶質低，而以GE薄膜操作時，阻擋率則無明顯變化。於未加電場條件下，以DK薄膜操作於pH值為3，氯化鈣濃度100 ppm之條件下，因薄膜帶較強之正電荷，可使鈣離子阻擋率維持於90%以上，因此有較佳之分離效果，其以鈣離子為基準之選擇分離率為8.55；而GE薄膜則是操作於pH值為3.5，氯化鈣濃度1000 ppm時，有較高之選擇分離率3.32。施加電場後，於pH值3.5時，GE薄膜之鈣離子阻擋率可提升至98%以上，而葡萄糖阻擋率僅有15%，其選擇分離率可達60.87，且仍可維持較高之通量。

關鍵字

奈米過濾；葡萄糖；電場

並列摘要

In industrial processes, selective separation of solutions containing neutral solute and salts is generally used membrane filtration such as nanofiltration. The salt ions may alter the electrical properties of membranes and the hydrated radius of the neutral solute, then affecting the sieving effect of the neutral solute and the Donnan effect of salt ions when there are forced to transport through the membrane. In the study, three different nanomembranes were used experimentally for separating solutions containing glucose and calcium chloride . The flux and rejection of single solute solution and mixed solutions were discussed and the effects of calcium chloride concentrations, operating pressure and pH value on the separation performance were also analyzed.. Finally, an electric field was imposed on the filter to investigate the effect of the external force on the enhancement of filtration performance.
Experimental results from NF270 membrane showed that it has higher fluxes than the other two membranes. However, its pore size is smaller than the Stoke’s diameter of calcium ion and glucose, and more than 85% rejection of both the solutes was observed. It indicated that that NF270 membrane is not suitable for selective separation of the solution. Comparing the rejection of solutes of mixed and single-solute solutions showed that for DK membrane the former has lower rejections of both solutes. However, only a slight variation in rejection was observed when GE membrane was used.
Experimental results from DK and GE membrane with mixed solution showed that the rejection of calcium ion is more than 90% and selectivity factor based on Ca+2 is higher than 8.55 by DK membrane with pH= 3 and CaCl2 concentration of 100 ppm. However, the selectivity factor by GE membrane was only about 3.2 obtained in the study. When an electric field as 250 V/m was imposed on the GE membrane, the rejections of glucose and calcium ion is 15% and 98% respectively at pH=3.5. Not only the selectivity factor is increased to 60.9, but also can maintain a high flux.

並列關鍵字

nanofiltration；glucose；electric field

參考文獻

李成豪，“奈米過濾膜電荷密度分析及其對過濾效能影響之探討”，私立中原大學化學工程研究所，碩士學位論文(2010)。

許家銘，“以電場掃流超過濾分離蛋白質混合液”，私立中原大學化學工程研究所，碩士學位論文(2000)。

溫家瑋，“電場奈米過濾特性之研究”，私立中原大學化學工程研究所，碩士學位論文(2008)。

Al-Rashdi, B. A. M., Johnson, D. J. and Hilal, N., Removal of heavy metal ions by nanofiltration, Desalination, 315 (2013) 2-17.

Almazán, J. E., Romero-Dondiz, E. M., Rajal, V. B. and Castro-Vidaurre, E. F., Nanofiltration of glucose: Analysis of parameters and membrane characterization, Chemical Engineering Research and Design, 94 (2014) 485-493.