Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow

The present paper employs Molecular Dynamics (MD) simulations to reveal nanoscale ion separation from water/ion flows under an external electric field in Poiseuille-like nanochannels. Ions are drifted to the sidewalls due to the effect of wall-normal applied electric fields while flowing inside the...

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Main Authors: Filippos Sofos, Theodoros Karakasidis, Ioannis E. Sarris
Format: Article
Language:English
Published: MDPI AG 2020-11-01
Series:Nanomaterials
Subjects:
Online Access:https://www.mdpi.com/2079-4991/10/12/2373
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author Filippos Sofos
Theodoros Karakasidis
Ioannis E. Sarris
author_facet Filippos Sofos
Theodoros Karakasidis
Ioannis E. Sarris
author_sort Filippos Sofos
collection DOAJ
description The present paper employs Molecular Dynamics (MD) simulations to reveal nanoscale ion separation from water/ion flows under an external electric field in Poiseuille-like nanochannels. Ions are drifted to the sidewalls due to the effect of wall-normal applied electric fields while flowing inside the channel. Fresh water is obtained from the channel centerline, while ions are rejected near the walls, similar to the Capacitive DeIonization (CDI) principles. Parameters affecting the separation process, i.e., simulation duration, percentage of the removal, volumetric flow rate, and the length of the nanochannel incorporated, are affected by the electric field magnitude, ion correlations, and channel height. For the range of channels investigated here, an ion removal percentage near 100% is achieved in most cases in less than 20 ns for an electric field magnitude of E = 2.0 V/Å. In the nutshell, the ion drift is found satisfactory in the proposed nanoscale method, and it is exploited in a practical, small-scale system. Theoretical investigation from this work can be projected for systems at larger scales to perform fundamental yet elusive studies on water/ion separation issues at the nanoscale and, one step further, for designing real devices as well. The advantages over existing methods refer to the ease of implementation, low cost, and energy consumption, without the need to confront membrane fouling problems and complex electrode material fabrication employed in CDI.
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spelling doaj.art-a3ad08342a464d9284d83374031825d82023-11-20T22:47:21ZengMDPI AGNanomaterials2079-49912020-11-011012237310.3390/nano10122373Molecular Dynamics Simulations of Ion Drift in Nanochannel Water FlowFilippos Sofos0Theodoros Karakasidis1Ioannis E. Sarris2Physics Department, University of Thessaly, 35100 Lamia, GreecePhysics Department, University of Thessaly, 35100 Lamia, GreeceDepartment of Mechanical Engineering, University of West Attica, 12244 Athens, GreeceThe present paper employs Molecular Dynamics (MD) simulations to reveal nanoscale ion separation from water/ion flows under an external electric field in Poiseuille-like nanochannels. Ions are drifted to the sidewalls due to the effect of wall-normal applied electric fields while flowing inside the channel. Fresh water is obtained from the channel centerline, while ions are rejected near the walls, similar to the Capacitive DeIonization (CDI) principles. Parameters affecting the separation process, i.e., simulation duration, percentage of the removal, volumetric flow rate, and the length of the nanochannel incorporated, are affected by the electric field magnitude, ion correlations, and channel height. For the range of channels investigated here, an ion removal percentage near 100% is achieved in most cases in less than 20 ns for an electric field magnitude of E = 2.0 V/Å. In the nutshell, the ion drift is found satisfactory in the proposed nanoscale method, and it is exploited in a practical, small-scale system. Theoretical investigation from this work can be projected for systems at larger scales to perform fundamental yet elusive studies on water/ion separation issues at the nanoscale and, one step further, for designing real devices as well. The advantages over existing methods refer to the ease of implementation, low cost, and energy consumption, without the need to confront membrane fouling problems and complex electrode material fabrication employed in CDI.https://www.mdpi.com/2079-4991/10/12/2373nanochannel flowselectric fieldion separationmolecular dynamics
spellingShingle Filippos Sofos
Theodoros Karakasidis
Ioannis E. Sarris
Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
Nanomaterials
nanochannel flows
electric field
ion separation
molecular dynamics
title Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
title_full Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
title_fullStr Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
title_full_unstemmed Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
title_short Molecular Dynamics Simulations of Ion Drift in Nanochannel Water Flow
title_sort molecular dynamics simulations of ion drift in nanochannel water flow
topic nanochannel flows
electric field
ion separation
molecular dynamics
url https://www.mdpi.com/2079-4991/10/12/2373
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