Selective Rubidium Recovery Using Zeolitic Potassium Hexacyanoferrate Nanomaterial Electrode in Capacitive Deionization

Truong, DQ; Choo, Y; Nguyen, TV; Naidu, G

Selective Rubidium Recovery Using Zeolitic Potassium Hexacyanoferrate Nanomaterial Electrode in Capacitive Deionization

Truong, DQ Choo, Y

Nguyen, TV Naidu, G

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Publisher:: WILEY
Publication Type:: Journal Article
Citation:: Small Structures, 2025
Issue Date:: 2025-01-01

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Field	Value	Language
dc.contributor.author	Truong, DQ
dc.contributor.author	Choo, Y https://orcid.org/0000-0003-2715-0618
dc.contributor.author	Nguyen, TV
dc.contributor.author	Naidu, G
dc.date.accessioned	2025-09-03T07:57:30Z
dc.date.available	2025-09-03T07:57:30Z
dc.date.issued	2025-01-01
dc.identifier.citation	Small Structures, 2025
dc.identifier.issn	2688-4062
dc.identifier.issn	2688-4062
dc.identifier.uri	http://hdl.handle.net/10453/189622
dc.description.abstract	Rubidium (Rb) mining from seawater brine is promising as a sustainable renewable resource. Selectively recovering Rb from saline brine is challenging. Capacitive deionization (CDI), an electrosorption process, offers the capacity to extract Rb rapidly with selective electrodes. This study reports CDI electrodes utilizing potassium cobalt hexacyanoferrate (KCoFC-AC) and ZIF-embedded KCoFC (KCoFC@ZIF-AC) nanomaterials for selective Rb uptake. The feasibility of the fabricated Rb-selective electrodes is established by detail electrochemical characterizations. Compared to conventional carbon electrode, the fabricated electrodes exhibited a notably higher Rb selectivity. Specifically, the Rb uptake capacities of the composite electrodes with single Rb and mixed monovalent solution (Rb, Na, K) ranged from 78 to 127 mg g<sup>−1</sup> and 57 to 103 mg g<sup>−1</sup>, respectively. The enhanced performance of KCoFC@ZIF-AC compared to KCoFC-AC is attributed to the presence of the ZIF component, which promotes Rb penetration into the lattice structure of KCoFC. Moreover, the saturated electrodes demonstrated reusability multiple times with periodic chemical regeneration processes. In seawater, both fabricated electrodes exhibited an excellent Rb extraction rate (≈90%) with minor uptake of major cations (Na, Mg, K, and Ca). The superior Rb selectivity of the fabricated electrodes underscore the role of ion -exchange nanomaterial in CDI electrode for achieving rapid Rb extraction from brine.
dc.language	English
dc.publisher	WILEY
dc.relation.ispartof	Small Structures
dc.relation.isbasedon	10.1002/sstr.202500273
dc.rights	info:eu-repo/semantics/openAccess
dc.title	Selective Rubidium Recovery Using Zeolitic Potassium Hexacyanoferrate Nanomaterial Electrode in Capacitive Deionization
dc.type	Journal Article
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
pubs.organisational-group	University of Technology Sydney/UTS Groups
pubs.organisational-group	University of Technology Sydney/UTS Groups/Centre for Technology in Water and Wastewater (CTWW)
pubs.organisational-group	University of Technology Sydney/UTS Groups/Chancellor's Research Fellows
utslib.copyright.status	open_access	*
dc.rights.license	This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/
dc.date.updated	2025-09-03T07:57:27Z
pubs.publication-status	Published

Abstract:

Rubidium (Rb) mining from seawater brine is promising as a sustainable renewable resource. Selectively recovering Rb from saline brine is challenging. Capacitive deionization (CDI), an electrosorption process, offers the capacity to extract Rb rapidly with selective electrodes. This study reports CDI electrodes utilizing potassium cobalt hexacyanoferrate (KCoFC-AC) and ZIF-embedded KCoFC (KCoFC@ZIF-AC) nanomaterials for selective Rb uptake. The feasibility of the fabricated Rb-selective electrodes is established by detail electrochemical characterizations. Compared to conventional carbon electrode, the fabricated electrodes exhibited a notably higher Rb selectivity. Specifically, the Rb uptake capacities of the composite electrodes with single Rb and mixed monovalent solution (Rb, Na, K) ranged from 78 to 127 mg g⁻¹ and 57 to 103 mg g⁻¹, respectively. The enhanced performance of KCoFC@ZIF-AC compared to KCoFC-AC is attributed to the presence of the ZIF component, which promotes Rb penetration into the lattice structure of KCoFC. Moreover, the saturated electrodes demonstrated reusability multiple times with periodic chemical regeneration processes. In seawater, both fabricated electrodes exhibited an excellent Rb extraction rate (≈90%) with minor uptake of major cations (Na, Mg, K, and Ca). The superior Rb selectivity of the fabricated electrodes underscore the role of ion -exchange nanomaterial in CDI electrode for achieving rapid Rb extraction from brine.

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http://hdl.handle.net/10453/189622