Interaction-based ion selectivity exhibited by self-assembled, cross-linked zwitterionic copolymer membranes
Interaction-based ion selectivity exhibited by self-assembled, cross-linked zwitterionic copolymer membranes
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DOI：
10.1073/pnas.2022198118
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发表时间：
2021-09-14
影响因子：
11.1
通讯作者：
Asatekin, Ayse
中科院分区：
文献类型：
--
作者：
Lounder, Samuel J.;Asatekin, Ayse
具有高级离子选择性的水过滤膜是资源回收和清洁饮用水生产的迫切需要。本研究研究了交联两性离子共聚物膜的分离能力，这是一种具有亚纳米两性离子纳米通道的自组装膜系统。我们证明，选择性两性离子-阴离子相互作用同时控制盐的分配和扩散，NaClO4、NaI、NaBr、NaCl、NaF和Na2SO4的渗透性在广泛的进料浓度范围内大致跨越三个数量级。我们采用基于Maxwell-Stefan方程的一维输运模型对盐通量进行建模，并表明扩散是1:1钠盐的主要输运方式。两性离子-Cl-和两性离子-F-相互作用的差异使这些膜具有超高的Cl-/F-选择性（PCl-/PF-= 24），即使在NaCl和NaF的盐水混合物中也能保持高氟化物保留率和高氯化物传代率。
Water filtration membranes with advanced ion selectivity are urgently needed for resource recovery and the production of clean drinking water. This work investigates the separation capabilities of cross-linked zwitterionic copolymer membranes, a self-assembled membrane system featuring subnanometer zwitterionic nanochannels. We demonstrate that selective zwitterion-anion interactions simultaneously control salt partitioning and diffusivity, with the permeabilities of NaClO4, NaI, NaBr, NaCl, NaF, and Na2SO4 spanning roughly three orders of magnitude over a wide range of feed concentrations. We model salt flux using a one-dimensional transport model based on the Maxwell-Stefan equations and show that diffusion is the dominant mode of transport for 1:1 sodium salts. Differences in zwitterion-Cl- and zwitterion-F- interactions granted these membranes with the ultrahigh Cl-/F- permselectivity (PCl-/PF-= 24), enabling high fluoride retention and high chloride passage even from saline mixtures of NaCl and NaF.