On the origin of membrane potential in membranes with polarizable nanopores

Ryzhkov, Ilya I.; Лебедев, Д. В.; Солодовниченко, В. С.; Минаков, А. В.; Симунин, М. М.

doi:10.1016/j.memsci.2017.11.073

Cited by 33 publications

(41 citation statements)

References 62 publications

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“…[12] The SC model is centred on the combination of the Navier-Stokes, Poisson and Nernst-Planck equations and can be derived to account for immobile or ionizible charges and fluid slip on the pore walls . [13,14,15,16,17,18,19,20,21] The UP model drops the radial dependence of the electrical potential in the pore as described by the Poisson equation and consider the radial potential uniform. [22,23,24,25,26] This simplification limits the validity of the UP model to dilute solutions and narrow pore diameters; This condition is fulfilled when the electrical double layers (EDLs) inside the pores overlap.…”

Section: Introductionmentioning

confidence: 99%

AC-driven electro-osmotic flow in charged nanopores

Catalano¹,

Biesheuvel²

2018

EPL

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In this paper we report the theory describing the electro-osmotic flow in charged nanopores with constant radius and charge density driven by alternating current. We solve the ion and solution transport in unsteady conditions as described by the Navier-Stokes and Nernst-Planck equations considering the electrical potential inside the charged nanopore uniform in the radial direction (Uniform Potential model approximation). We derive the transport equation system in the case in which the pore is connected to two boundary diffusion layers and the cations and anions have different diffusion coefficients. This approach allows the theoretical description of the characteristic frequency dependence of the phase shift between the applied current density and the electro-osmotic flow. Additionally we show how the analysis of the dynamic response of the electro-osmotic coupling factor versus the AC frequency allows us to quantify the apparent ion diffusion coefficient in membranes. Notably, the frequency window where the phase-shift is predicted is well inside the commonly used sampling rate for electro-osmotic flow experiments f ∈ 10 −4 , 10 1 Hz, hence the proposed method can be useful to determine the apparent diffusion coefficient of ions (such as redox complex for flow batteries) in charged membranes.

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Section: Introductionmentioning

confidence: 99%

AC-driven electro-osmotic flow in charged nanopores

Catalano¹,

Biesheuvel²

2018

EPL

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“…When the membrane is not charged externally by injecting or withdrawing electrons to or from the conductive membrane pore walls, one has X e = 0. However, even then the local value X e (z) can be non-zero since electrons are redistributed along the surface in order to ensure equipotential in the pore wall [33,44]. The volumetric density of wall charge is X = X c + X e , which is opposite in sign to the density of ionic charges c + − c − in the pore because of total charge neutrality…”

Section: Theoretical Modelmentioning

confidence: 99%

Theory of Ion and Water Transport in Electron-Conducting Membrane Pores with p H-Dependent Chemical Charge

Zhang¹,

Biesheuvel²,

Ryzhkov

2019

Phys. Rev. Applied

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In this work, we develop an extended uniform potential (UP) model for a membrane nanopore by including two different charging mechanisms of the pore walls, namely by electronic charge and by chemical charge. These two charging mechanisms will generally occur in polymeric membranes with conducting agents, or membranes made of conducting materials like carbon nanotubes with surface ionizable groups. The electronic charge redistributes along the pore in response to the gradient of electric potential in the pore, while the chemical charge depends on the local pH via a Langmuir-type isotherm. The extended UP model shows good agreement with experimental data for membrane potential measured at zero current condition. When both types of charge are present, the ratio of the electronic charge to the chemical charge can be characterized by the dimensionless number of surface groups and the dimensionless capacitance of the dielectric Stern layer. The performance of the membrane pore in converting osmotic energy from a salt concentration difference into electrical power can be improved by tuning the electronic charge.

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“…Therefore, it is necessary to control the transport and selective properties of a membrane in order to preserve it from any influence caused by these limitations. There are two main ways to affect the membrane's selective properties: changing the structure of pores (the geometry and physico-chemical properties of the surface) [10,11], including using composite membranes [12]) or external exposure (transmembrane potential, external electric fields [13][14][15], pH of the solution [16], temperature, radiation, etc. ).…”

Section: Introductionmentioning

confidence: 99%

“…However, this method is difficult to use, for example, in the synthesis of inorganic solid membranes. The surface modification technique is the most convenient method in this case [11]. The surface modification technique deals with deposition of nanoparticles onto a membrane.Silicate (high silica) porous glasses (PGs) are channel-type nanostructures [20] with thermal, chemical and microbiological stability, in combination with controlled surface structural characteristics [21][22][23].…”

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Glass/Au Composite Membranes with Gold Nanoparticles Synthesized inside Pores for Selective Ion Transport

Лебедев¹,

Novomlinsky²,

Kochemirovsky³

et al. 2020

Materials

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4Grebenshchikov Institute of Silicate Chemistry (ISCh) RAS, 2 Adm. Makarova emb., St Petersburg 199155, Russia; anfimova-i@mail.ru (I.A.); antr2@yandex.ru (T.A.) Abstract: Nanocomposite membranes have been actively developed in the last decade. The involvement of nanostructures can improve the permeability, selectivity, and anti-fouling properties of a membrane for improved filtration processes. In this work, we propose a novel type of ion-selective Glass/Au composite membrane based on porous glass (PG), which combines the advantages of porous media and promising selective properties. The latter are achieved by depositing gold nanoparticles into the membrane pores by the laser-induced liquid phase chemical deposition technique. Inside the pores, gold nanoparticles with an average diameter 25 nm were formed, which was confirmed by optical and microscopic studies. To study the transport and selective properties of the PG/Au composite membrane, the potentiometric method was applied. The uniform potential model was used to determine the surface charge from the experimental data. It was found that the formation of gold nanoparticles inside membrane pores leads to an increase in the surface charge from −2.75 mC/m 2 to −5.42 mC/m 2 . The methods proposed in this work allow the creation of a whole family of composite materials based on porous glasses. In this case, conceptually, the synthesis of these materials will differ only in the selection of initial precursors.Nanocomposite membranes have been actively developed in the last decade [17]. The involvement of nanostructures can improve the permeability, selectivity, and anti-fouling properties of a membrane for improved filtration processes. One of the most promising approaches to producing such composite materials is the formation of nanoparticles inside the porous structure of a membrane. As with nanotechnology in general [18], there are two main methods [17] for the formation of nanoparticles inside the membranous pores: "top down"-bulk modification through blending (called mixed-matrix membranes) and "bottom up"-surface modification. In the fabrication of bulk-modified nanocomposite membranes, the nanoparticles are dispersed in a homogeneous polymeric precursor solution before the final formation process [19]. However, this method is difficult to use, for example, in the synthesis of inorganic solid membranes. The surface modification technique is the most convenient method in this case [11]. The surface modification technique deals with deposition of nanoparticles onto a membrane.Silicate (high silica) porous glasses (PGs) are channel-type nanostructures [20] with thermal, chemical and microbiological stability, in combination with controlled surface structural characteristics [21][22][23]. Special attention is worth paying to the PG application for the separation of liquid mixtures by reverse osmosis. This method has found application in water desalination, sanitary household water cleaning, water regeneration from vital function products in space, radioactive ...

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On the origin of membrane potential in membranes with polarizable nanopores

Cited by 33 publications

References 62 publications

AC-driven electro-osmotic flow in charged nanopores

AC-driven electro-osmotic flow in charged nanopores

Theory of Ion and Water Transport in Electron-Conducting Membrane Pores with p H-Dependent Chemical Charge

Glass/Au Composite Membranes with Gold Nanoparticles Synthesized inside Pores for Selective Ion Transport

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