Electric Potential Profiles in a Model Single-Path Electrodialysis Unit
Electrodialysis is an important electromembrane separation process anticipated to play a significant role in developing future technologies. It produces ion-depleted and ion-concentrated product streams, intrinsically suggesting the formation of spatial gradients of relevant quantities. These quanti...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-11-01
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| Series: | Membranes |
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| Online Access: | https://www.mdpi.com/2077-0375/12/11/1136 |
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| author | Jan Pagáč Petr Kovář Zdeněk Slouka |
| author_facet | Jan Pagáč Petr Kovář Zdeněk Slouka |
| author_sort | Jan Pagáč |
| collection | DOAJ |
| description | Electrodialysis is an important electromembrane separation process anticipated to play a significant role in developing future technologies. It produces ion-depleted and ion-concentrated product streams, intrinsically suggesting the formation of spatial gradients of relevant quantities. These quantities affect local conditions in an electrodialysis unit. To investigate the spatial distribution of electric potentials, we constructed a model electrodialysis system with a single diluate channel that included ports for inserting reference electrodes measuring potential profiles. We validated our system and measurement methods in a series of control experiments under a solution flow rate of 250 µL/min and current densities between 10 and 52 A/m<sup>2</sup>. The collected data showed that the electric potential in the diluate channel did not change in the vertical direction (direction of gravity force), and only minimally varied in the diluate channel center in the flow direction. Although we could not reconstruct the potential profile within ion-depleted layers due to the resolution of the method, we found appreciable potential variation across the diluate channel. The most significant potential drops were localized on the membranes with the developed ion-depleted zones. Interestingly, these potential drops abruptly increased when we applied current loads, yielding almost complete desalination. The increase in the resistance accompanied by relatively large fluctuations in the measured potential indicated the system transition into limiting and overlimiting regions, and the onset of overlimiting convection. |
| first_indexed | 2024-03-09T18:08:43Z |
| format | Article |
| id | doaj.art-344fb711b0964ef8a9ccdb6f6ae43086 |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-09T18:08:43Z |
| publishDate | 2022-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-344fb711b0964ef8a9ccdb6f6ae430862023-11-24T09:12:22ZengMDPI AGMembranes2077-03752022-11-011211113610.3390/membranes12111136Electric Potential Profiles in a Model Single-Path Electrodialysis UnitJan Pagáč0Petr Kovář1Zdeněk Slouka2Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, 16628 Prague, Czech RepublicDepartment of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, 16628 Prague, Czech RepublicDepartment of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, 16628 Prague, Czech RepublicElectrodialysis is an important electromembrane separation process anticipated to play a significant role in developing future technologies. It produces ion-depleted and ion-concentrated product streams, intrinsically suggesting the formation of spatial gradients of relevant quantities. These quantities affect local conditions in an electrodialysis unit. To investigate the spatial distribution of electric potentials, we constructed a model electrodialysis system with a single diluate channel that included ports for inserting reference electrodes measuring potential profiles. We validated our system and measurement methods in a series of control experiments under a solution flow rate of 250 µL/min and current densities between 10 and 52 A/m<sup>2</sup>. The collected data showed that the electric potential in the diluate channel did not change in the vertical direction (direction of gravity force), and only minimally varied in the diluate channel center in the flow direction. Although we could not reconstruct the potential profile within ion-depleted layers due to the resolution of the method, we found appreciable potential variation across the diluate channel. The most significant potential drops were localized on the membranes with the developed ion-depleted zones. Interestingly, these potential drops abruptly increased when we applied current loads, yielding almost complete desalination. The increase in the resistance accompanied by relatively large fluctuations in the measured potential indicated the system transition into limiting and overlimiting regions, and the onset of overlimiting convection.https://www.mdpi.com/2077-0375/12/11/1136electrodialysiselectric potentialdiluateoverlimiting currentdesalination |
| spellingShingle | Jan Pagáč Petr Kovář Zdeněk Slouka Electric Potential Profiles in a Model Single-Path Electrodialysis Unit Membranes electrodialysis electric potential diluate overlimiting current desalination |
| title | Electric Potential Profiles in a Model Single-Path Electrodialysis Unit |
| title_full | Electric Potential Profiles in a Model Single-Path Electrodialysis Unit |
| title_fullStr | Electric Potential Profiles in a Model Single-Path Electrodialysis Unit |
| title_full_unstemmed | Electric Potential Profiles in a Model Single-Path Electrodialysis Unit |
| title_short | Electric Potential Profiles in a Model Single-Path Electrodialysis Unit |
| title_sort | electric potential profiles in a model single path electrodialysis unit |
| topic | electrodialysis electric potential diluate overlimiting current desalination |
| url | https://www.mdpi.com/2077-0375/12/11/1136 |
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