Sodium chloride sorption in sulfonated polymers for membrane applications
Sodium chloride sorption in sulfonated polymers for membrane applications
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DOI：
10.1016/j.memsci.2012.08.014
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发表时间：
2012-12-15
影响因子：
9.5
通讯作者：
Paul, Donald R.
中科院分区：
文献类型：
--
作者：
Geise, Geoffrey M.;Falcon, Linda P.;Paul, Donald R.
离子吸附测量被用来表征钠和氯在磺化聚合物中的吸附，以用于膜应用。以交联型聚乙二醇二丙烯酸酯为基础的不带电聚合物作为比较对象。带电聚合物包括一种磺化聚砜无规共聚物和两相分离的磺化苯乙烯五嵌段共聚物。在中性pH条件下，聚合物膜与0.01-1.0molNaC l-1水溶液平衡后，测量了吸附在这些聚合物中的钠离子和氯离子浓度。用聚合物灰化技术和火焰原子吸收光谱测定了磺化聚合物的阳离子吸附。用解吸技术和离子色谱测定了阴离子的吸附。聚合物电荷，即磺化作用，影响离子吸附。总体而言，在所有考虑的聚合物中，随着吸水率的增加，盐的吸收率也增加。在不带电荷的聚合物中，如预期的那样，吸附的钠和氯化物的摩尔浓度相等。然而，由于离子交换，磺化聚合物吸附的钠离子比氯离子多得多。实验的移动盐(即阴离子)吸附数据符合一个模型，该模型包含了Donnan排除和简单盐分配对聚合物整体盐分吸收的贡献。一般来说，Donnan排除对阴离子(即可移动盐)在这些阳离子交换材料中的吸附的影响随着吸水率的增加而降低，推测部分原因是水化聚合物的磺酸基被稀释。(C)2012爱思唯尔B.V.保留所有权利。
Ion sorption measurements were conducted to characterize sodium and chloride sorption in sulfonated polymers of interest for membrane applications. An uncharged polymer, based on cross-linked poly(ethylene glycol diacrylate), was included for comparison. The charged polymers included a sulfonated polysulfone random copolymer and two phase separated sulfonated styrenic pentablock copolymers. The sodium and chloride ion concentrations sorbed in these polymers were measured after polymer films had been equilibrated with 0.01-1.0 mol L-1 aqueous NaCl solutions at neutral pH. For the sulfonated polymers, cation sorption was measured using a polymer ashing technique and flame atomic absorption spectrophotometry. Anion sorption was measured using a desorption technique and ion chromatography. Polymer charge, i.e., sulfonation, influenced ion sorption. In general, salt sorption increased as water sorption increased in all polymers considered. In the uncharged polymer, the molar concentrations of sorbed sodium and chloride were equal to one another, as expected. However, the sulfonated polymers sorbed much more sodium than chloride ions due to ion exchange. The experimental mobile salt (i.e., anion) sorption data were fit to a model containing contributions from both Donnan exclusion and simple salt partitioning to the overall salt uptake by the polymer. In general, the influence of Donnan exclusion on anion (i.e., mobile salt) sorption in these cation exchange materials is reduced as water uptake increases, presumably due, in part, to dilution of the hydrated polymer's sulfonate groups. (C) 2012 Elsevier B.V. All rights reserved.