Influence of water content on alkali metal chloride transport in cross-linked Poly(ethylene glycol) Diacrylate.1. Ion sorption
Influence of water content on alkali metal chloride transport in cross-linked Poly(ethylene glycol) Diacrylate.1. Ion sorption
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DOI：
10.1016/j.polymer.2019.121554
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发表时间：
2019-09-12
期刊：
影响因子：
4.6
通讯作者：
Freeman, Benny D.
中科院分区：
文献类型：
--
作者：
Jang, Eui-Soung;Kamcev, Jovan;Freeman, Benny D.
研究了离子大小与水膨胀不带电聚合物中离子吸附特性之间的关系，作为理解更复杂系统（即带电聚合物网络）中离子吸附和传输的模型系统。测定了一系列交联聚乙二醇二丙烯酸酯（XLPEGDA）聚合物膜对碱金属氯化物（如LiCl、NaCl和KCl）的吸附系数随外源盐浓度0.01 ~ 1.0 m的变化规律，其吸附系数的相对顺序为：KCl > LiCl > NaCl。这个顺序与离子水化大小的顺序（即Li+ > Na+ > K+）并不对应。XLPEGDA聚合物对碱金属氯化物的吸附行为受离子水合作用和聚合物离子特异性相互作用的影响。制备了具有三种不同平衡吸水值的XLPEGDA聚合物，研究了水含量对这些聚合物中盐吸附的影响。通常，离子吸附系数随着聚合物含水量的增加而增加。对聚合物中的盐活度系数进行了量化，以更好地了解聚合物网络中离子的热力学非理想性。采用Flory-Rehner理论，基于盐的吸附测量，预测了盐溶液平衡聚合物中的水体积分数。
The relationship between ion size and sorption properties in water swollen uncharged polymers was investigated as a model system for understanding ion sorption and transport in more complex systems (i.e., charged polymer networks). Alkali metal chloride (e.g., LiCl, NaCl, and KCl) sorption coefficients in a series of cross-linked poly (ethylene glycol) diacrylate (XLPEGDA) polymer membranes were measured as a function of external salt concentrations ranging from 0.01 to 1.0 M. The relative order of salt sorption coefficients was: KCl > LiCl > NaCl. This order does not correspond to the order of ion hydration size (i.e., Li+ > Na+ > K+). The alkali metal chloride sorption behavior in XLPEGDA polymers is influenced by both ion hydration and polymer-ion specific interactions. XLPEGDA polymers having three different equilibrium water uptake values were prepared to investigate the effect of water content on salt sorption in these polymers. Generally, ion sorption coefficients increase as polymer water content increases. Salt activity coefficients in the polymers were quantified to better understand the thermodynamic non-ideality of ions in polymer networks. Flory-Rehner theory was used to predict water volume fraction in the polymers equilibrated with salt solution based on salt sorption measurements.