It is of significant importance to develop highly monovalent anion-selective membranes (MASM) having stable structure for a wide range of applications. To realize the efficient monovalent/bivalent anion separation, in this work, three amphoteric ion-exchange membranes (AIEMs) through blending were fabricated for use in electrodialysis (ED). The three membranes were prepared by blending amino-containing poly(arylene ether sulfone) (PAES-NH₂) with 10, 15, and 20 wt% of sulfonated polysulfone (SPSf), respectively, followed by grafting imidazolium salt-terminated side alkyl chains on PAES backbone. Our investigations demonstrate that each transparent AIEM shows good miscibility between the two components, which has been verified by a homogeneous structure via SEM observation and by an even distribution of N element via EDX mapping. In the ED process at a current density of 2.5 mA cm^–2, AIEM with 15 wt% of SPSf shows the superior perm-selectivity (Cl^–/SO₄^2–) of 21.8, relative to many reported MASMs having modified surfaces (< 6.0), which is synergistically contributed by (i) electrostatic repulsion difference from the negatively-charged sulfonate groups against monovalent Cl^– ions and bivalent SO₄^2– ions and (ii) hydrated energy difference of hydrated Cl^–/SO₄^2– ions. This work thus presents a strategy to guide the architectural design of advanced MASMs.

开发具有稳定结构的高单价阴离子选择性膜（MASM）对于广泛的应用至关重要。为了实现有效的单价/二价阴离子分离，在这项工作中，通过混合制备了两个两性离子交换膜（AIEM），用于电渗析（ED）。通过分别将含氨基的聚亚芳基醚砜（PAES-NH ₂）与10、15和20 wt％的磺化聚砜（SPSf）混合，然后接枝咪唑鎓盐末端的侧链烷基来制备这三种膜在PAES骨干上。我们的研究表明，每个透明AIEM在两个组件之间都显示出良好的可混溶性，这已经通过以下方式的同质结构进行了验证：SEM观察和通过EDX映射得到的N元素均匀分布。在ED过程中，电流密度为2.5 mA cm ^–2时，相对于许多报道的具有改性表面的MASM，具有15 wt％SPSf的AIEM表现出21.8的优异电导选择性（Cl ^– / SO ₄ ^2–）。 6.0），这是协同贡献的从对一价Cl为基准的带负电荷的磺酸酯基团（ⅰ）的静电排斥差^-离子和二价SO _4根^2-离子和（ii）水合氯的水合能量差^- / SO ₄ ^2-离子。因此，这项工作提出了一种策略，可指导高级MASM的体系结构设计。