以離子交換薄膜進行笨／環已烷的滲透蒸發之研究

呂幸江 ； 王逢展

《化工》 51卷3期 (2004/06) Pp. 37-51

https://doi.org/10.29803/CE.200406.0005

摘要

本研究是以Neosepta-CMX陽離子交換薄膜進行滲透蒸發，探討苯與環己烷分離的效果。並探討將Neosepta薄膜中的鈉離子置換成銅離子的影響，更進一步探討苯與環己烷於Neosepta薄膜中的滲透蒸發的質傳模式。結果顯示，不論薄膜含銅或鈉離子，對苯的吸附與擴散均大於環己烷，銅型薄膜對於此系統之純溶劑之吸附選擇率約為2.5，高於鈉型薄膜的1.5。而以銅型薄膜而言，苯的擴散係數(4.0×10^(-13)～5.0×10^(-13)平方公尺/s)略高於環己烷之擴散係數(3.0×10^(-13)平方公尺/s)。因此銅型薄膜整體的滲透蒸發的效果亦高於鈉型薄膜(2.6-3.5 vs.1.2-1.6)。
苯／環己烷的混合液在銅型薄膜中的吸附現象可以UNIQUAC模式描述，而其擴散係數也可以用Long's model模擬。用modified Maxwell-Stefan equation結合上述的吸附與擴散行為，發現滲透蒸發的實驗結果與模擬結果相當吻合，可作為滲透蒸發程序的質傳模擬。

並列摘要

The sorption, diffusion, and pervaporation (PV) properties of benzene/cyclohexane (Bz/Cx) mixtures on cation-exchange membranes were investigated. The pure solvent sorption ratio of Bz/Cx was 1.53 for the Na (superscript +)-membrane and 2.59 for the Cu (superscript 2+)-membrane. The diffusivity of Bz in Cu-membrane was higher than that Cx. Therefore the Cu (superscript 2+)-membrane exhibited a higher PV selectivity of Bz/Cx than Na (superscript +)-membrane. The equilibrium sorption isotherms of pure vapors in the membranes and the partial solubility of binary solutions in the membranes were described using the UNIQUAC model. The transient regimes of vapor sorption were employed to calculate the concentration-dependent diffusion coefficients. Long's model sufficiently explained the diffusivity of Bz and Cx in the membranes. Excellent agreement was found with the experimental results applying the solubility and diffusivity data to simulate the pervaporation performance (flux and selectivity) using the modified Maxwell-Stefan equation. The membrane containing Cu(superscript 2+)ion demonstrates better facilitating capability for Bz transport than that with Na(superscript +), mainly due to its preferential sorption property toward Bz. Replacing Na(superscript +) with Cu(superscript 2+) into a Neosepta membrane resulted in better separation efficiency and higher Bz flux throughout the entire Bz concentration range.