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Title: Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination

Abstract

Chloride ion, the majority salt in nature, is ~52% faster than sodium ion (D Na+ = 1.33, D Cl- = 2.03[10 -9m 2s -1]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ~(D - –D +)/(D - + D +). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ~50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).

Authors:
 [1];  [2];  [1];  [3];  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Singapore-MIT Alliance for Research and Technology (SMART) Centre (Singapore)
  3. Singapore-MIT Alliance for Research and Technology (SMART) Centre (Singapore)
Publication Date:
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1557428
Grant/Contract Number:  
AR0000294
Resource Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Kwak, Rhokyun, Pham, Van Sang, Kim, Bumjoo, Chen, Lan, and Han, Jongyoon. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination. United States: N. p., 2016. Web. doi:10.1038/srep25349.
Kwak, Rhokyun, Pham, Van Sang, Kim, Bumjoo, Chen, Lan, & Han, Jongyoon. Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination. United States. doi:10.1038/srep25349.
Kwak, Rhokyun, Pham, Van Sang, Kim, Bumjoo, Chen, Lan, and Han, Jongyoon. Mon . "Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination". United States. doi:10.1038/srep25349. https://www.osti.gov/servlets/purl/1557428.
@article{osti_1557428,
title = {Enhanced Salt Removal by Unipolar Ion Conduction in Ion Concentration Polarization Desalination},
author = {Kwak, Rhokyun and Pham, Van Sang and Kim, Bumjoo and Chen, Lan and Han, Jongyoon},
abstractNote = {Chloride ion, the majority salt in nature, is ~52% faster than sodium ion (DNa+ = 1.33, DCl- = 2.03[10-9m2s-1]). Yet, current electrochemical desalination technologies (e.g. electrodialysis) rely on bipolar ion conduction, removing one pair of the cation and the anion simultaneously. Here, we demonstrate that novel ion concentration polarization desalination can enhance salt removal under a given current by implementing unipolar ion conduction: conducting only cations (or anions) with the unipolar ion exchange membrane stack. Combining theoretical analysis, experiment, and numerical modeling, we elucidate that this enhanced salt removal can shift current utilization (ratio between desalted ions and ions conducted through electrodes) and corresponding energy efficiency by the factor ~(D- –D+)/(D- + D+). Specifically for desalting NaCl, this enhancement of unipolar cation conduction saves power consumption by ~50% in overlimiting regime, compared with conventional electrodialysis. Recognizing and utilizing differences between unipolar and bipolar ion conductions have significant implications not only on electromembrane desalination, but also energy harvesting applications (e.g. reverse electrodialysis).},
doi = {10.1038/srep25349},
journal = {Scientific Reports},
number = 1,
volume = 6,
place = {United States},
year = {2016},
month = {5}
}

Journal Article:
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Cited by: 21 works
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