Boron and salt ion transport in electrically assisted reverse osmosis

Herein, we report a novel electrically assisted reverse osmosis (EARO) process which integrates an electrochemical process with the conventional RO process. We systematically investigated the behaviors of boron and salt ion (i.e., Na+ and Cl−) transporting through a commercial seawater RO (SWRO) mem...

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Main Authors: Bao, Xian, Long, Wei, Liu, Hong, She, Qianhong
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2022
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Online Access:https://hdl.handle.net/10356/160374
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1603742022-07-20T05:15:19Z Boron and salt ion transport in electrically assisted reverse osmosis Bao, Xian Long, Wei Liu, Hong She, Qianhong School of Civil and Environmental Engineering Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre Engineering::Environmental engineering Electrically Assisted Reverse Osmosis Desalination Herein, we report a novel electrically assisted reverse osmosis (EARO) process which integrates an electrochemical process with the conventional RO process. We systematically investigated the behaviors of boron and salt ion (i.e., Na+ and Cl−) transporting through a commercial seawater RO (SWRO) membrane in the EARO process under a range of applied voltages by employing an external porous carbon cloth as cathode on the SWRO membrane surface. The SWRO membrane in the EARO process exhibited a significantly enhanced boron rejection of 93.8% under the applied voltage of 4 V compared with the conventional RO process (~75.0%). The enhancement in boron removal efficiency in EARO is mainly attributed to the locally elevated pH near the RO membrane surface caused by water electrolysis. At elevated pH, boron transforms from the uncharged boric acid to negatively charged and sized-increased borate ion and is more favorably rejected by the SWRO membrane. On the other hand, the variation of salt ion rejection was marginal with increasing the applied voltages in EARO. This study demonstrates that the EARO has a great potential to achieve low-chemical and low-cost boron removal in one-pass RO seawater desalination. To make this process more practically feasible, the future efforts need to optimize the development of the electrically conductive feed spacer and the membrane module. Ministry of Education (MOE) This research was supported by the Ministry of Education, Singapore, under the Academic Research Fund Tier 1 (RG84/19). 2022-07-20T05:15:18Z 2022-07-20T05:15:18Z 2021 Journal Article Bao, X., Long, W., Liu, H. & She, Q. (2021). Boron and salt ion transport in electrically assisted reverse osmosis. Journal of Membrane Science, 637, 119639-. https://dx.doi.org/10.1016/j.memsci.2021.119639 0376-7388 https://hdl.handle.net/10356/160374 10.1016/j.memsci.2021.119639 2-s2.0-85110272887 637 119639 en RG84/19 Journal of Membrane Science © 2021 Elsevier B.V. All rights reserved.
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Engineering::Environmental engineering
Electrically Assisted Reverse Osmosis
Desalination
spellingShingle Engineering::Environmental engineering
Electrically Assisted Reverse Osmosis
Desalination
Bao, Xian
Long, Wei
Liu, Hong
She, Qianhong
Boron and salt ion transport in electrically assisted reverse osmosis
description Herein, we report a novel electrically assisted reverse osmosis (EARO) process which integrates an electrochemical process with the conventional RO process. We systematically investigated the behaviors of boron and salt ion (i.e., Na+ and Cl−) transporting through a commercial seawater RO (SWRO) membrane in the EARO process under a range of applied voltages by employing an external porous carbon cloth as cathode on the SWRO membrane surface. The SWRO membrane in the EARO process exhibited a significantly enhanced boron rejection of 93.8% under the applied voltage of 4 V compared with the conventional RO process (~75.0%). The enhancement in boron removal efficiency in EARO is mainly attributed to the locally elevated pH near the RO membrane surface caused by water electrolysis. At elevated pH, boron transforms from the uncharged boric acid to negatively charged and sized-increased borate ion and is more favorably rejected by the SWRO membrane. On the other hand, the variation of salt ion rejection was marginal with increasing the applied voltages in EARO. This study demonstrates that the EARO has a great potential to achieve low-chemical and low-cost boron removal in one-pass RO seawater desalination. To make this process more practically feasible, the future efforts need to optimize the development of the electrically conductive feed spacer and the membrane module.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Bao, Xian
Long, Wei
Liu, Hong
She, Qianhong
format Article
author Bao, Xian
Long, Wei
Liu, Hong
She, Qianhong
author_sort Bao, Xian
title Boron and salt ion transport in electrically assisted reverse osmosis
title_short Boron and salt ion transport in electrically assisted reverse osmosis
title_full Boron and salt ion transport in electrically assisted reverse osmosis
title_fullStr Boron and salt ion transport in electrically assisted reverse osmosis
title_full_unstemmed Boron and salt ion transport in electrically assisted reverse osmosis
title_sort boron and salt ion transport in electrically assisted reverse osmosis
publishDate 2022
url https://hdl.handle.net/10356/160374
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