In nature, efficient and selective ion transport is facilitated by ion-conductive channels in cell membranes; these channels reveal an architectural design with specialized functionality. Drawing inspiration from this, mechanistic insights into the angstrom-scale-channel membrane composed of ionic-crosslinked polybenzimidazole and sulfonated poly(ether ether ketone), exhibiting functional differentiation and efficient ion-sieving properties are presented. Nanochannels allow for strong hydrogen-bonding interactions with hydrated ions of higher polarity, while rendering significant electrostatic charge effects that impede the transition of multivalent ions by compressing effective passageways. Both hydrogen bonding and electrostatic interactions synergistically result in high selectivity for monovalent ions over multivalent ions because the latter requires overcoming higher energy barriers for transport compared with the former, thereby causing varying extents of ion dehydration within the nanochannels. The resulting membrane achieves a high monovalent ion permeation rate of 1.35 mol m⁻² h⁻¹ with a high mono/multivalent ion selectivity of 56.5 for K⁺/Mg²⁺ and 286 for K⁺/Al³⁺.

中文翻译：

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埃级通道具有多功能离子膜相互作用，可通过电渗析实现精确的离子分离


在自然界中，细胞膜中的离子传导通道促进了高效且选择性的离子传输。这些通道揭示了具有专门功能的建筑设计。受此启发，对由离子交联聚苯并咪唑和磺化聚醚醚酮组成的埃级通道膜的机理进行了深入研究，该膜表现出功能差异化和高效的离子筛分特性。纳米通道允许与较高极性的水合离子发生强氢键相互作用，同时产生显着的静电荷效应，通过压缩有效通道来阻碍多价离子的转变。氢键和静电相互作用协同导致单价离子相对于多价离子的高选择性，因为与前者相比，后者需要克服更高的传输能垒，从而导致纳米通道内不同程度的离子脱水。所得膜实现了1.35mol m ^-2 h ^-1的高单价离子渗透速率，以及K ⁺ /Mg ²⁺ 56.5和K ⁺ /Al ³⁺ 286的高单价/多价离子选择性。