Effects of co-ions on transport of iodide ions through a non-conventional anion exchange paper membrane
Effects of co-ions on transport of iodide ions through a non-conventional anion exchange paper membrane
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DOI：
10.1016/j.memsci.2003.10.009
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发表时间：
2004-01-15
影响因子：
9.5
通讯作者：
Inoue, H
中科院分区：
文献类型：
--
作者：
Inoue, H
研究共离子对含约0.30meq的三甲基羟丙基铵基团的新型阴离子交换纸膜中碘离子迁移的影响。在10(-3)~10(-1)moldm(-3)浓度-电池体系中，测定了7种碘盐(1：1-电解质)的干膜离子交换容量、跨膜电位、膜电导和离子通量。在离子传输分析中，通过线性唯象方程引入了导电膜渗透率和扩散膜渗透率，前者表示溶液/膜离子在静电作用下的分布，后者表示离子在膜相内的迁移速度，考虑到离子对的扩散，并随共离子的渗透和扩散而增大。碘离子的电导膜透过率随水合共离子半径的增加而线性增加，r(2)=0.855，而扩散膜的渗透率随晶体共离子半径的增加而线性增加，r(2)=0.899。纸膜的这些结果与合成两性膜和纳米孔膜的结果不同，在合成的两性膜和纳米孔膜中，两种电荷的离子都是均匀渗透的，膜的透过率随着共离子半径的增加而降低。这表明，由于阴离子交换纸膜具有足够大的孔径，离子可以自由地渗透到膜基质中，因此碘离子的传输可能部分由依赖于表面阳离子电荷密度的共离子传输控制，而不是取决于阴离子交换纸膜的离子半径。(C)2003爱思唯尔B.V.保留所有权利。
To study the effects of co-ions on iodide ion transport through a novel anion exchange paper membrane containing trimethyihydroxypropylammonium groups with approximately 0.30 meq. g(-1) dry-membrane ion exchange capacity, transmembrane potential, membrane conductance and ionic fluxes were measured in the concentration-cell system for seven kinds of iodine salts (1: 1-electrolytes) at 10(-3) to 10(-1) mol dm(-3). For analysis of ion transport, the electroconductive membrane permeability, representing the solution/membrane ion distribution due to electrostatic effects, and the diffusional membrane permeability, representing the migration speed of ions within the membrane phase, concerning ion pair diffusion, and increasing with co-ion penetration and diffusion, were introduced in terms of linear phenomenological equations. Electroconductive membrane permeabilities of iodide ions were found to increase linearly with increasing hydrated co-ion radii; r(2) = 0.855, while diffusional membrane permeabilities of iodide ions increased linearly with increasing crystal co-ion radii; r(2) = 0.899. These results for a paper membrane differ from those of synthetic amphoteric membrane and nanoporus membranes in which ions of both charges penetrate equally, in which membrane permeabilities decreased with increasing co-ion radii. This suggests that iodide ion transport may be partially controlled by co-ion transport dependent on surface cationic charge density rather than ion radii in the anion exchange paper membrane, as the pores are large enough for ions to freely permeate within membrane matrix. (C) 2003 Elsevier B.V. All rights reserved.