Elucidation of Ion Solvation in Ion-Exchange Resins and Interpretation of Separation Selectivity

已经研究了两种方法来阐明离子交换分离的选择性。一是阐明了树脂中离子的溶剂化作用。二是分离行为的物理模拟。通过改变溶剂和离子交换中心的结构，初步研究了离子在离子交换树脂中的溶剂化作用。对阴离子交换的研究表明，离子交换中心的溶剂化作用对总分离选择性的影响不大，而反离子的溶剂化作用则很重要。离子的分离选择性基本上可以用离子交换位与反离子之间形成离子对来解释。这一结果包含在一个新的物理模型的离子交换的基础上静电理论。从Poisson-Boltzmann方程出发，导出了能解释离子交换树脂与溶液界面上各种现象的方程。聚醚与铵离子化学键合在硅胶上的络合物的形成，聚醚与阳离子交换树脂中的抗衡阳离子的络合，以及通常的离子交换分离都很好地解释了发达的模型。结果表明，离子对的形成、离子的专一性吸附和离子在双电层中的积累是决定离子交换选择性的决定性因素.此外，本文还研究了Bronsted酸作为杂共轭阴离子的毛细管电泳和超声波对离子交换的影响.本文方法可用于测定各种Bronsted酸与阴离子结合的杂共轭阴离子形成常数。此外，它表明，超声可以被用作外部应力，以改变和修改的分离选择性。超声波的这种效应是由声压传输引起的局部温度升高引起的。

Two approaches have been investigated to elucidate ion-exchange separation selectivity. One is the elucidation of the solvation of ions in the resin. The other is physical modeling of separation behaviors. The solvation of ions in ion-exchange resin was studied basically by changing solvents and the structures of ion-exchange sites. Studies on anion-exchange indicated that the solvation of ion-exchange sites is not important in the determination of overall separation selectivity, while the solvation of counterious is very important. The separation selectivity of ions can be basically explained by ion-pair formation between ion-exchange sites and counterions. This result was included in a novel physical model for ion-exchange based on electrostatic theories. Starting from the Poisson-Boltzmann equation, some equations capable of explaining various phenomena occurring at the interface between ion-exchange resins and solution were derived. The complex formation of polyethers with ammonium ion chemically bonded on silica gel, the complexation of polyethers with countercations in cation-exchange resins, and usual ion-exchange separation were very well explained by developed models. Results strongly suggest that ion-pair formation, specific adsorption of ions, and the accumulation of ions in electrical double layr play decisive roles for the determination of ion-exchange selectivity.In addition, capillary electrophoresis of Bronsted acids as heteroconjugated anions and effects of ultrasound on ion-exchange have been also studied. Reliable heteroconjugated anion formation constants can be determined for various combination of Bronsted acids with anions by the developed mthod. In addition, it was shown that ultrasound can be used as external stress to vary and modify the separation selectivity. This effects of ultrasound is caused by local temperature increases induced by the transmission of acoustic pressure.