Theory of ion and water transport in reverse osmosis membranes
We present theory for ion and water transport through reverse osmosis membranes based on a Maxwell-Stefan framework combined with hydrodynamic theory for the reduced motion of particles in thin pores. We include all driving forces and frictions both on the fluid (water), and on the ions, including i...
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ftdatacite:10.48550/arxiv.1706.06835 2023-05-15T15:52:42+02:00 Theory of ion and water transport in reverse osmosis membranes Oren, Y. S. Biesheuvel, P. M. 2017 https://dx.doi.org/10.48550/arxiv.1706.06835 https://arxiv.org/abs/1706.06835 unknown arXiv https://dx.doi.org/10.1103/physrevapplied.9.024034 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Chemical Physics physics.chem-ph FOS Physical sciences article-journal Article ScholarlyArticle Text 2017 ftdatacite https://doi.org/10.48550/arxiv.1706.06835 https://doi.org/10.1103/physrevapplied.9.024034 2022-04-01T10:26:37Z We present theory for ion and water transport through reverse osmosis membranes based on a Maxwell-Stefan framework combined with hydrodynamic theory for the reduced motion of particles in thin pores. We include all driving forces and frictions both on the fluid (water), and on the ions, including ion-fluid friction as well as ion-wall friction. By including the acid-base character of the carbonic acid system, the boric acid system, H$_3$O$^+$/OH$^-$, and the membrane charge, we locally determine pH and thus the effective charge of the membrane as well as the dissociation degree of boric acid. We present calculation results for a dead end experiment with fixed feed concentration, where effluent composition is a self-consistent function of fluxes through the membrane. Comparison with experimental results from literature for fluid flow vs. pressure, and for salt and boron rejection, shows that theory agrees well with data. Our model is based on realistic assumptions for the effective sizes of the ions and for the diameter of the RO membrane pore in the polyamide toplayer ($\sim$0.75 nm). Text Carbonic acid DataCite Metadata Store (German National Library of Science and Technology) |
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Chemical Physics physics.chem-ph FOS Physical sciences |
spellingShingle |
Chemical Physics physics.chem-ph FOS Physical sciences Oren, Y. S. Biesheuvel, P. M. Theory of ion and water transport in reverse osmosis membranes |
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Chemical Physics physics.chem-ph FOS Physical sciences |
description |
We present theory for ion and water transport through reverse osmosis membranes based on a Maxwell-Stefan framework combined with hydrodynamic theory for the reduced motion of particles in thin pores. We include all driving forces and frictions both on the fluid (water), and on the ions, including ion-fluid friction as well as ion-wall friction. By including the acid-base character of the carbonic acid system, the boric acid system, H$_3$O$^+$/OH$^-$, and the membrane charge, we locally determine pH and thus the effective charge of the membrane as well as the dissociation degree of boric acid. We present calculation results for a dead end experiment with fixed feed concentration, where effluent composition is a self-consistent function of fluxes through the membrane. Comparison with experimental results from literature for fluid flow vs. pressure, and for salt and boron rejection, shows that theory agrees well with data. Our model is based on realistic assumptions for the effective sizes of the ions and for the diameter of the RO membrane pore in the polyamide toplayer ($\sim$0.75 nm). |
format |
Text |
author |
Oren, Y. S. Biesheuvel, P. M. |
author_facet |
Oren, Y. S. Biesheuvel, P. M. |
author_sort |
Oren, Y. S. |
title |
Theory of ion and water transport in reverse osmosis membranes |
title_short |
Theory of ion and water transport in reverse osmosis membranes |
title_full |
Theory of ion and water transport in reverse osmosis membranes |
title_fullStr |
Theory of ion and water transport in reverse osmosis membranes |
title_full_unstemmed |
Theory of ion and water transport in reverse osmosis membranes |
title_sort |
theory of ion and water transport in reverse osmosis membranes |
publisher |
arXiv |
publishDate |
2017 |
url |
https://dx.doi.org/10.48550/arxiv.1706.06835 https://arxiv.org/abs/1706.06835 |
genre |
Carbonic acid |
genre_facet |
Carbonic acid |
op_relation |
https://dx.doi.org/10.1103/physrevapplied.9.024034 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1706.06835 https://doi.org/10.1103/physrevapplied.9.024034 |
_version_ |
1766387813539905536 |