摘要
本文比较了一系列二价金属反离子的Nafion阳离子交换膜的渗透气化行为。对水/乙醇体系,水为优先渗透组份。Ba^(2+)表现出很小的渗透通量和较高的分离系数,而Mg^(2+)、Ca^(2+)、Sr^(2+)的渗透通量几乎相等,分离系数则按:Mg^(2+)<Ca^(2+)<Sr^(2+)的顺序略有提高。四种二价过渡金属离子Co^(2+),Ni^(2+),Cu^(2+),Zn^(2+)中,以Co^(2+)的通量最小,分离系数相对较大:而Zn^(2+)则有较大的通量及对应较小的分离糸数。Nafion/Mg^(2+)膜的溶胀度(DS)在30wt.%H_2O附近表现出极大值,而总的渗透通量在45wt.%H_2O左右也呈现出极大值。对54.5wt.%EtOH的料液,求得两种渗透组份的表观渗透活化能相近:E_(H_2o)=5.90Kcal/mol,E_(EroH)=6.22Kcal/mal。
The pervaporation behavior of Nafion cation exchange membranes loading with a series of different divalent counter-ions was compared. For the water/ethanol system,water is the preferred permeation component. Ba^(2+) displays very small flux and relatively high separation factor, but the flux for Mg^(2+), Ca^(2+), Sr(2+) is approximately the same, and the separation factor increases slightly in the following sequence:Mg^(2+)<Ca^(2+)<Sr(2~). Among the four divalent transition metal counter-ions Co^(2+), Ni^(2+), Cu^(2+), Zn^(2+) , the flux for Cos^(2+) is the smallest, and the separation factor is comparatively high. Zn^(2+) has larger flux coupled with a lower separation factor. The degree of swelling (DS) of membrane Nafion/Mg^(2+) displays a maximum when exposed to～30%wt. %H_2O ethanol-water feed solution, and the total flux also displays a maximum when the feed composition is ～45wt. %H_2O. For 54.5wt. %E(?)OH feed solution, the apparent permeation energy of activation for both components was calculated, they are approximately equal: E_(H_2o)=5.90Kcal/mol,E_(E_1OH)=6.22Kcal/mol.
出处
《膜科学与技术》
CAS
CSCD
1992年第2期29-34,共6页
Membrane Science and Technology
关键词
膜分离
水
乙醇
离子交换膜
气化
pervaporation, Nafion, cation exchange membrane, water/ethanol separation
