The mixture effect on ionic selectivity and permeability of nanotubes

Wang, Mao; Shen, Weijun; Wang, Xue; Zhang, Gehui; Zhao, Shuang; Liu, Feng

doi:10.1039/d0na00089b

Cited by 3 publications

(1 citation statement)

References 45 publications

(71 reference statements)

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“…These single-salt measurements often do not reflect the selectivities that one will observe in mixtures due to changes in partitioning and electrical potential gradients. [157,164,207] Thus, whenever possible separations should occur with ion mixtures.…”

Section: Discussionmentioning

confidence: 99%

Ion separations with membranes

Tang

Bruening

2020

Journal of Polymer Science

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Ion separations are important for resource recovery, water treatment, and energy production and storage. Techniques such as chemical precipitation, selective adsorption, and solvent extraction are effective, but membranes may separate ions continuously with less waste and lower energy costs. Separation of monovalent and multivalent ions with nanofiltration or electrodialysis membranes already enables water softening and edible salt purification. Similar membranes are attractive as separators in vanadium redox flow batteries. Selective partitioning of divalent counter-ions into ion-exchange membranes even allows transport of these ions against their concentration gradients in salt mixtures. However, separations of ions with the same charge is more challenging. Recent research demonstrated highly selective ion "sieving" at small scales. Separations using electrical potentials and differences in ion electrophoretic mobilities are promising, but relatively unexplored. Carrier-mediated transport affords high selectivity in liquid membranes, but these systems are not very stable, and selective transport via hopping between anchored carriers has proven elusive. Finally, this paper discusses how concentration polarization decreases selectivities in many membrane processes. Although development of selective, inexpensive ion-separation membranes is a work in progress, successes in water softening and edible salt purification suggests that future selective membranes will serve as complementary methods to traditional purification techniques.

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Section: Discussionmentioning

confidence: 99%

Ion separations with membranes

Tang

Bruening

2020

Journal of Polymer Science

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Molecular design of covalent−organic framework membranes for Li+/Mg2+ separation: Significant charge effect

Lyu

Wang²,

Jiang³

et al. 2022

Journal of Membrane Science

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Optimizing selectivity via membrane molecular packing manipulation for simultaneous cation and anion screening

Meng,

Li,

Lai

et al. 2024

Sci. Adv.

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Advancing membranes with enhanced solute-solute selectivity is essential for expanding membrane technology applications, yet it presents a notable challenge. Drawing inspiration from the unparalleled selectivity of biological systems, which benefit from the sophisticated spatial organization of functionalities, we posit that manipulating the arrangement of the membrane’s building blocks, an aspect previously given limited attention, can address this challenge. We demonstrate that optimizing the face-to-face orientation of building blocks during the assembly of covalent-organic-framework (COF) membranes improves ion-π interactions with multivalent ions. This optimization leads to extraordinary selectivity in differentiating between monovalent cations and anions from their multivalent counterparts, achieving selectivity factors of 214 for K + /Al 3+ and 451 for NO 3 − /PO 4 3− . Leveraging this attribute, the COF membrane facilitates the direct extraction of NaCl from seawater with a purity of 99.57%. These findings offer an alternative approach for designing highly selective membrane materials, offering promising prospects for advancing membrane-based technologies.

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The mixture effect on ionic selectivity and permeability of nanotubes

Abstract: Selective ion transport deteriorates in mixed salt solutions. This mixture effect originates from the increased or relatively less decreased permeability of lower permeable ions due to their reduced preferential adsorption on the charged nanotubes.

Cited by 3 publications

References 45 publications

Ion separations with membranes

Ion separations with membranes

Molecular design of covalent−organic framework membranes for Li+/Mg2+ separation: Significant charge effect

Optimizing selectivity via membrane molecular packing manipulation for simultaneous cation and anion screening

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