Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis

<p dir="ltr">Alkali-earth metals pose a significant challenge to water treatment technologies and electrochemical processes due to their propensity to precipitate as metal hydroxides, which can deposit on membranes and/or electrodes and reduce their efficiencies. Membraneless electro...

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Main Author: Nafis Mahmud (14150004) (author)
Other Authors: Daniela V. Fraga Alvarez (17151004) (author), Mohamed H. Ibrahim (14778124) (author), Muftah H. El-Naas (2662543) (author), Daniel V. Esposito (3130605) (author)
Published: 2022
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_version_ 1864513553283678208
author Nafis Mahmud (14150004)
author2 Daniela V. Fraga Alvarez (17151004)
Mohamed H. Ibrahim (14778124)
Muftah H. El-Naas (2662543)
Daniel V. Esposito (3130605)
author2_role author
author
author
author
author_facet Nafis Mahmud (14150004)
Daniela V. Fraga Alvarez (17151004)
Mohamed H. Ibrahim (14778124)
Muftah H. El-Naas (2662543)
Daniel V. Esposito (3130605)
author_role author
dc.creator.none.fl_str_mv Nafis Mahmud (14150004)
Daniela V. Fraga Alvarez (17151004)
Mohamed H. Ibrahim (14778124)
Muftah H. El-Naas (2662543)
Daniel V. Esposito (3130605)
dc.date.none.fl_str_mv 2022-03-01T00:00:00Z
dc.identifier.none.fl_str_mv 10.1016/j.desal.2021.115489
dc.relation.none.fl_str_mv https://figshare.com/articles/journal_contribution/Magnesium_recovery_from_desalination_reject_brine_as_pretreatment_for_membraneless_electrolysis/24314260
dc.rights.none.fl_str_mv CC BY 4.0
info:eu-repo/semantics/openAccess
dc.subject.none.fl_str_mv Engineering
Chemical engineering
Mechanical engineering
Reject brine
Membraneless electrolyzers
Magnesium
Fouling
Optimization
Purification
dc.title.none.fl_str_mv Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
dc.type.none.fl_str_mv Text
Journal contribution
info:eu-repo/semantics/publishedVersion
text
contribution to journal
description <p dir="ltr">Alkali-earth metals pose a significant challenge to water treatment technologies and electrochemical processes due to their propensity to precipitate as metal hydroxides, which can deposit on membranes and/or electrodes and reduce their efficiencies. Membraneless electrolyzers can partially overcome this issue because they lack membranes or diaphragms, however their electrodes are still susceptible to fouling. To overcome this issue, electrolyzers can be incorporated into a recirculating electrolyte scheme where magnesium is removed in the form of Mg(OH)<sub>2</sub> before reaching the electrolyzer. Motivated by this system, the first part of this study focuses on the optimization of magnesium recovery from desalination brine by adding NaOH using response surface methodology. Brine salinity, NaOH dose, and temperature were optimized with complete magnesium removal set as the target response using central composite design. Results showed that 98.8% of magnesium can be removed at brine salinity, NaOH dose, and temperature of 73.5 g/L, 8.22 g/L and 45.5 °C, respectively. The second part of this study investigated the influence of Mg<sup>2+</sup> concentration on the performance of a cathode within a membraneless electrolyzer. Experimental demonstrations show that Mg<sup>2+</sup> concentrations below 5 mM can be used as a feed stream without any noticeable build-up of Mg(OH)<sub>2</sub> deposits on the cathode surface over 3 h during electrolysis at 50 mA/cm<sup>2</sup>. Finally, an analysis is presented to predict how long a cathode can operate in Mg<sup>2+</sup>-containing electrolyte as a function of current density and superficial velocity of brine solution before the electrode reached its maximum tolerance of Mg(OH)<sub>2</sub> deposits.</p><h2>Other Information</h2><p dir="ltr">Published in: Desalination<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.desal.2021.115489" target="_blank">https://dx.doi.org/10.1016/j.desal.2021.115489</a></p>
eu_rights_str_mv openAccess
id Manara2_2c4efd9ff53f0ade72b5ef99a7299af3
identifier_str_mv 10.1016/j.desal.2021.115489
network_acronym_str Manara2
network_name_str Manara2
oai_identifier_str oai:figshare.com:article/24314260
publishDate 2022
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rights_invalid_str_mv CC BY 4.0
spelling Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysisNafis Mahmud (14150004)Daniela V. Fraga Alvarez (17151004)Mohamed H. Ibrahim (14778124)Muftah H. El-Naas (2662543)Daniel V. Esposito (3130605)EngineeringChemical engineeringMechanical engineeringReject brineMembraneless electrolyzersMagnesiumFoulingOptimizationPurification<p dir="ltr">Alkali-earth metals pose a significant challenge to water treatment technologies and electrochemical processes due to their propensity to precipitate as metal hydroxides, which can deposit on membranes and/or electrodes and reduce their efficiencies. Membraneless electrolyzers can partially overcome this issue because they lack membranes or diaphragms, however their electrodes are still susceptible to fouling. To overcome this issue, electrolyzers can be incorporated into a recirculating electrolyte scheme where magnesium is removed in the form of Mg(OH)<sub>2</sub> before reaching the electrolyzer. Motivated by this system, the first part of this study focuses on the optimization of magnesium recovery from desalination brine by adding NaOH using response surface methodology. Brine salinity, NaOH dose, and temperature were optimized with complete magnesium removal set as the target response using central composite design. Results showed that 98.8% of magnesium can be removed at brine salinity, NaOH dose, and temperature of 73.5 g/L, 8.22 g/L and 45.5 °C, respectively. The second part of this study investigated the influence of Mg<sup>2+</sup> concentration on the performance of a cathode within a membraneless electrolyzer. Experimental demonstrations show that Mg<sup>2+</sup> concentrations below 5 mM can be used as a feed stream without any noticeable build-up of Mg(OH)<sub>2</sub> deposits on the cathode surface over 3 h during electrolysis at 50 mA/cm<sup>2</sup>. Finally, an analysis is presented to predict how long a cathode can operate in Mg<sup>2+</sup>-containing electrolyte as a function of current density and superficial velocity of brine solution before the electrode reached its maximum tolerance of Mg(OH)<sub>2</sub> deposits.</p><h2>Other Information</h2><p dir="ltr">Published in: Desalination<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.desal.2021.115489" target="_blank">https://dx.doi.org/10.1016/j.desal.2021.115489</a></p>2022-03-01T00:00:00ZTextJournal contributioninfo:eu-repo/semantics/publishedVersiontextcontribution to journal10.1016/j.desal.2021.115489https://figshare.com/articles/journal_contribution/Magnesium_recovery_from_desalination_reject_brine_as_pretreatment_for_membraneless_electrolysis/24314260CC BY 4.0info:eu-repo/semantics/openAccessoai:figshare.com:article/243142602022-03-01T00:00:00Z
spellingShingle Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
Nafis Mahmud (14150004)
Engineering
Chemical engineering
Mechanical engineering
Reject brine
Membraneless electrolyzers
Magnesium
Fouling
Optimization
Purification
status_str publishedVersion
title Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
title_full Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
title_fullStr Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
title_full_unstemmed Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
title_short Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
title_sort Magnesium recovery from desalination reject brine as pretreatment for membraneless electrolysis
topic Engineering
Chemical engineering
Mechanical engineering
Reject brine
Membraneless electrolyzers
Magnesium
Fouling
Optimization
Purification