Water and ion sorption in a series of cross-linked AMPS/PEGDA hydrogel membranes
Water and ion sorption in a series of cross-linked AMPS/PEGDA hydrogel membranes
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一系列交联 AMPS/PEGDA 水凝胶膜中的水和离子吸附
DOI：
10.1016/j.polymer.2018.05.021
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发表时间：
2018
期刊：
影响因子：
4.6
通讯作者：
B. Freeman
中科院分区：
文献类型：
--
作者：
N. Yan;D. R. Paul;B. Freeman
离子交换膜的电荷密度对水和离子的吸附有深远的影响。然而，在广泛的电荷密度范围内，对带电膜中水和离子吸附的基础研究并不广泛，这使得在此类材料中建立基本的结构/性质关系变得困难。本研究以聚乙二醇二丙烯酸酯（PEGDA）与2-丙烯酰胺-2-甲基丙磺酸（AMPS）共聚制备了一系列均相交联无电荷磺化水凝胶膜。测定了膜内平衡吸水量和离子含量（Na+、Cl−）随外部NaCl浓度（0.01 ~ 1.0 mol/L）的变化规律。随着聚合物固定电荷密度的增加，水和反离子（Na+）的吸附均增加。随着聚合物固定电荷密度的适度增加，co-离子（Cl−）的吸附明显减少，这表明即使低水平的固定电荷也会显著排除co-离子。然而，在较高的电荷密度下，Cl -的吸附与电荷密度无关。由于溶液和膜相中离子的热力学非理想性，吸附Cl -浓度的实验值偏离了通过理想Donnan模型得到的结果。
Charge density of ion exchange membranes (IEMs) profoundly influences water and ion sorption. However, fundamental studies of water and ion sorption in charged membranes over a wide range of charge densities are not widely available, which makes it difficult to establish fundamental structure/property relations in such materials. In this study, a series of homogeneous cross-linked uncharged and sulfonated hydrogel membranes were prepared using poly(ethylene glycol diacrylate) (PEGDA) copolymerized with 2-acrylamido-2-methylpropanesulfonic acid (AMPS). Equilibrium water uptake and ion content (Na+, Cl−) in the membranes were determined as a function of external NaCl concentration (0.01–1.0 mol/L). As polymer fixed charge density increased, both water and counter-ion (Na+) sorption increased. Co-ion (Cl−) sorption decreased markedly with only modest increases in polymer fixed charge density, suggesting that even low levels of fixed charges exclude co-ions significantly. However, Cl−sorption became independent of charge density at higher levels of charge density. Experimental values for sorbed Cl−concentrations deviated from those obtained via ideal Donnan model due to thermodynamic non-idealities of ions in the solution and membrane phases.