The effect of counter-ions on the ion selectivity of potassium and sodium ions in nanopores

AbstractBiological sodium channels ferry sodium ions across the lipid membrane while rejecting potassium ions and other metal ions. Realizing such ion selectivity in an artificial solid-state ionic device will enable new separation technologies but remains highly challenging. In this work, we report an artificial sodium-selective ionic device, built on synthesized porous crown-ether crystals which consist of densely packed 0.26-nm-wide pores. The Na+ selectivity of the artificial sodium-selective ionic device reached 15 against K + , which is comparable to the biological counterpart, 523 against Ca2 + , which is nearly two orders of magnitude higher than the biological one, and 1128 against Mg2 + . The selectivity may arise from the size effect and molecular recognition effect. This work may contribute to the understanding of the structure-performance relationship of ion selective nanopores.

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Power Generation From Concentration Gradient by Reverse Electrodialysis in Ion Selective Nanochannel

ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2009-82208 ◽

2009 ◽

Author(s):

Dong-Kwon Kim ◽

Chuanhua Duan ◽

Yu-Feng Chen ◽

Arun Majumdar

Keyword(s):

Power Generation ◽

Concentration Gradient ◽

Ion Selectivity ◽

Electrical Energy ◽

Anodic Bonding ◽

Channel Height ◽

Cmos Process ◽

Surface Charges ◽

Reverse Electrodialysis ◽

Counter Ions

In this article, ion selective nanochannels are studied to generate electric power from concentration gradient by reverse electrodialysis. When nanochannels bring into contact with aqueous solution, the surface of nanochannels acquires charges from ionization, ion adsorption, and ion dissolution. These surface charges draw counter-ions toward the surface and repel co-ions away. Therefore, when an electrolyte concentration gradient is applied to nanochannels, counter-ions are transported through nanochannels much more easily than co-ions, which results in a net charge migration of ions. Gibbs free energy of mixing, which forces ion diffusion, thus can be converted into electrical energy by using ion-selective nanochannels. Silica nanochannels with heights of 26 nm and 80 nm fabricated by glass-silicon anodic bonding were used in this study. We experimentally investigated the power generation from these nanochannels placed between two potassium chloride solutions with various combinations of concentrations. The power generation per unit channel volume increases when the concentration gradient increases, while it decreases as channel height decreases. The highest power density measured is 26 kW/m3. Our data also indicates that the efficiency of energy conversion and the ion selectivity increase with a decrease of concentrations and channel height. The best efficiency obtained is 24%. Compared with ion-selective membranes, nanochannels promise more reliable operation since they are readily compatible with standard CMOS process and do not shrink and swell in response to their environment. Power generation from concentration gradient in ion selective nanochannels could be used in a variety of applications, including micro batteries and micro power generators.

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Electron spin resonance spectra of triple ions: anisotropic effects in the hyperfine splitting patterns of 23Na counter-ions

Canadian Journal of Chemistry ◽

10.1139/v69-562 ◽

1969 ◽

Vol 47 (18) ◽

pp. 3393-3396 ◽

Cited By ~ 20

Author(s):

T. E. Gough ◽

P. R. Hindle

Keyword(s):

Electron Spin Resonance ◽

Electron Spin ◽

Hyperfine Splitting ◽

Sodium Ion ◽

Electron Spin Resonance Spectroscopy ◽

Resonance Spectroscopy ◽

Sodium Ions ◽

Counter Ions ◽

Spin Resonance ◽

Triple Ions

The formation, in tetrahydrofuran, of triple ions of the formula Na2Q+ (Q = p-benzosemiquinone, 2,3-, 2,5-, 2,6-dimethyl-p-benzosemiquinone, durosemiquinone) has been detected by electron spin resonance spectroscopy. The spectra show asymmetric broadening within the 23Na hyperfine multiplets. From the direction of this broadening, it is deduced that the sodium ions lie in the plane of the semiquinone anion, one sodium ion associating with each oxygen.

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A new method for estimating counter-ion selectivity of a cationic association colloid: Trapping of interfacial chloride and bromide counter-ions by reaction with micellar bound aryldiazonium salts

Colloids and Surfaces ◽

10.1016/0166-6622(90)80223-q ◽

1990 ◽

Vol 48 ◽

pp. 123-137 ◽

Cited By ~ 27

Author(s):

John A. Loughlin ◽

Laurence S. Romsted

Keyword(s):

Ion Selectivity ◽

New Method ◽

Counter Ion ◽

Counter Ions

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Biomimetic potassium-selective nanopores

Science Advances ◽

10.1126/sciadv.aav2568 ◽

2019 ◽

Vol 5 (2) ◽

pp. eaav2568 ◽

Cited By ~ 37

Author(s):

Elif Turker Acar ◽

Steven F. Buchsbaum ◽

Cody Combs ◽

Francesco Fornasiero ◽

Zuzanna S. Siwy

Keyword(s):

Solid State ◽

Ion Selectivity ◽

Potassium Ions ◽

Sodium Ions ◽

Ionic Selectivity ◽

Pore Region ◽

Separation Processes ◽

Technological Potential ◽

Challenging Tasks

Reproducing the exquisite ion selectivity displayed by biological ion channels in artificial nanopore systems has proven to be one of the most challenging tasks undertaken by the nanopore community, yet a successful achievement of this goal offers immense technological potential. Here, we show a strategy to design solid-state nanopores that selectively transport potassium ions and show negligible conductance for sodium ions. The nanopores contain walls decorated with 4′-aminobenzo-18-crown-6 ether and single-stranded DNA (ssDNA) molecules located at one pore entrance. The ionic selectivity stems from facilitated transport of potassium ions in the pore region containing crown ether, while the highly charged ssDNA plays the role of a cation filter. Achieving potassium selectivity in solid-state nanopores opens new avenues toward advanced separation processes, more efficient biosensing technologies, and novel biomimetic nanopore systems.

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Ion mobility and partition determine the counter-ion selectivity of ion exchange membranes

10.31224/osf.io/zu3me ◽

2020 ◽

Author(s):

Matthias Wessling

Keyword(s):

Ion Exchange ◽

Ion Mobility ◽

Ion Selectivity ◽

Quantitative Relation ◽

Ion Exchange Membranes ◽

Membrane Conductivity ◽

Counter Ion ◽

Counter Ions ◽

New Perspective ◽

Two Parameters

Ion (perm)selectivity and conductivity are the two most essential properties of an ion exchange membrane, yet no quantitative relation between them has been suggested. In this work, the selectivity between two different counter-ions is correlated to the membrane conductivity. We show that the counter-ion selectivity measured by conventional electrodialysis (ED) can be expressed by the product of two parameters: (a) the mobility ratio between these two different counter-ions in the membrane and (b) their partition coefficient between the solution and the membrane. This is reminiscent of the classical solution-diffusion model. Via the counter-ion mobility in the membrane, the selectivity could be simply expressed with the membrane conductivity and dimensional swelling degree at pure counter-ion forms and at mixed counter-ion form when the membrane has been equilibrated with 1:1 equivalence ratio of the two counter-ions in the solution. This correlation is validated experimentally for the ion selectivity of K+/Na+ in two commercial hydrocarbon-based cation exchange membranes (CEMs). For K+/Na+ in a commercial perfluorosulfonic CEM, and for Mg2+/Na+ in all the three types of CEMs, the correlation could predict the counter-ion partition very well; but there is an underestimation of the K+/Na+ and Mg2+/Na+ mobility ratios afforded by this correlation, which might be due to simplification of the cation activity coefficients in CEMs. This work offers a convenient method to decouple experimentally the effect of partition and mobility in controlling the membrane selectivity, and also proposes a new perspective to study the selectivity as well as conductivity of ion exchange membranes.

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MODIFICATION OF DIRECT POTENTIOMETRIC METHOD FOR DETERMINING SODIUM IONS IN TECHNOLOGICAL AND WASTE SOLUTIONS OF HYDROMETALLURGICAL PRODUCTION

Mendeleev ◽

10.32743/2658-6495.2019.2.2.147 ◽

2019 ◽

Vol 2 (2) ◽

Author(s):

Sergey Aronbaev ◽

Sitora Zhuraeva ◽

Aminjon Umarov ◽

Alexander Kim ◽

Dmitry Aronbaev

Keyword(s):

Potentiometric Method ◽

Sodium Ions

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Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

10.26434/chemrxiv.7629467.v3 ◽

2019 ◽

Author(s):

Young-Kwang Jung ◽

Joaquin Calbo ◽

Ji-Sang Park ◽

Lucy D. Wahlley ◽

Sunghyun Kim ◽

...

Keyword(s):

First Principles ◽

Room Temperature ◽

Stokes Shift ◽

Green Luminescence ◽

Counter Ions ◽

Self Consistent ◽

Deep Ultraviolet ◽

Halide Perovskite ◽

Related Compounds ◽

Level Analysis

Cs4PbBr6 is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr64- octahedra with Cs+ counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs4PbBr6. We find a heavily compensated system where the room-temperature carrier concentrations (< 109 cm-3) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br3) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission.

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Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

10.26434/chemrxiv.7629467 ◽

2019 ◽

Cited By ~ 1

Author(s):

Young-Kwang Jung ◽

Joaquin Calbo ◽

Ji-Sang Park ◽

Lucy D. Wahlley ◽

Sunghyun Kim ◽

...

Keyword(s):

First Principles ◽

Room Temperature ◽

Stokes Shift ◽

Green Luminescence ◽

Counter Ions ◽

Self Consistent ◽

Deep Ultraviolet ◽

Halide Perovskite ◽

Related Compounds ◽

Level Analysis

Cs4PbBr6 is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr64- octahedra with Cs+ counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs4PbBr6. We find a heavily compensated system where the room-temperature carrier concentrations (< 109 cm-3) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br3) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission.

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