Selective Recovery of Rare Earth Elements and Valuable Metals from Mining Wastewater by Membrane/Adsorption Hybrid Systems

Fonseka Weeranarayana Mudalige, Charith D. J.

Selective Recovery of Rare Earth Elements and Valuable Metals from Mining Wastewater by Membrane/Adsorption Hybrid Systems

Fonseka Weeranarayana Mudalige, Charith D. J.

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Publication Type:: Thesis
Issue Date:: 2023

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Field	Value	Language
dc.contributor.author	Fonseka Weeranarayana Mudalige, Charith D. J.
dc.date.accessioned	2024-04-12T02:49:05Z
dc.date.available	2024-04-12T02:49:05Z
dc.date.issued	2023
dc.identifier.uri	http://hdl.handle.net/10453/177810
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_US.UTF-8
dc.description.abstract	Rare earth elements (REEs) have become a strategic resource extensively used in renewable energy technologies and modern electronic devices. Depletion of natural REE-bearing mineral deposits has made selective recovery of REEs from alternative sources crucial in meeting the rising global demand. Among REEs, Europium (Eu) is relatively scarce in the Earth's crust compared to more abundant elements. A previously reported method was used to synthesise a chromium-based metal-organic framework modified with N-(phosphonomethyl) iminodiacetic acid (PMIDA) in this study to selectively recover Eu from chemically complex zinc ore leachate. The adsorbent was characterized and comprehensively examined for Eu uptake as a function of adsorbate concentration, contact time, and pH of the solution. Cr-MIL-PMIDA showed a maximum adsorption capacity of 69.14 mg/g at pH 5.5 while adsorption kinetics best fitted the pseudo-second-order model. Furthermore, Cr-MIL-PMIDA showed exceptional selectivity (88%) toward Eu over competing transitional metal ions found in the dissolved mine ore. While Cr-MIL-PMIDA exhibits excellent properties for selective recovery of REE, there are practical challenges associated with its production cost and potential susceptibility to chromium leaching, making it less attractive for mass applications. To address these challenges, a highly stable, cost-effective, novel SBA15-NH-PMIDA material was then synthesized for the first time following a two-step surface modification process using PMIDA)for selective recovery of Europium (Eu). Initial, single solute Eu adsorption tests revealed that SBA15-NH-PMIDA reached equilibrium within two hours and showed a maximum Langmuir adsorption capacity of 86.21 mg/g at optimum pH 4.8. Selective adsorption tests were carried out with real acid mine drainage (AMD) collected from an abandoned mining site in northern Norway. The novel adsorbent selectively recovered over 80% of Eu from pH-adjusted real AMD at an optimum dosage of 0.8g/l. A Direct contact membrane distillation (DCMD)/adsorption hybrid system was then developed by suspending granulated SBA15-NH-PMIDA in the feed tank to remediate pH adjusted AMD. The system managed to concentrate Eu ions by over three folds to enable efficient selective recovery of Eu (over 90%), while uptake of other competing metals remained below 10%. SBA15-NH-PMIDA managed to retain over 90% of adsorption capacity over 10 regeneration cycles. The study revealed that, 193.2 g of EuCl3 with 99% purity can be recovered by treating 1000 m3 of AMD. Additionally, clean water recovered from the membrane system can be re used in mining activities to reduce water stress in arid regions.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en_US	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/177810/1/thesis.pdf
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	© 2023 Charith Fonseka
dc.rights	au.edu.uts.lib/cph
dc.title	Selective Recovery of Rare Earth Elements and Valuable Metals from Mining Wastewater by Membrane/Adsorption Hybrid Systems	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Rare earth elements (REEs) have become a strategic resource extensively used in renewable energy technologies and modern electronic devices. Depletion of natural REE-bearing mineral deposits has made selective recovery of REEs from alternative sources crucial in meeting the rising global demand. Among REEs, Europium (Eu) is relatively scarce in the Earth's crust compared to more abundant elements. A previously reported method was used to synthesise a chromium-based metal-organic framework modified with N-(phosphonomethyl) iminodiacetic acid (PMIDA) in this study to selectively recover Eu from chemically complex zinc ore leachate. The adsorbent was characterized and comprehensively examined for Eu uptake as a function of adsorbate concentration, contact time, and pH of the solution. Cr-MIL-PMIDA showed a maximum adsorption capacity of 69.14 mg/g at pH 5.5 while adsorption kinetics best fitted the pseudo-second-order model. Furthermore, Cr-MIL-PMIDA showed exceptional selectivity (88%) toward Eu over competing transitional metal ions found in the dissolved mine ore. While Cr-MIL-PMIDA exhibits excellent properties for selective recovery of REE, there are practical challenges associated with its production cost and potential susceptibility to chromium leaching, making it less attractive for mass applications. To address these challenges, a highly stable, cost-effective, novel SBA15-NH-PMIDA material was then synthesized for the first time following a two-step surface modification process using PMIDA)for selective recovery of Europium (Eu). Initial, single solute Eu adsorption tests revealed that SBA15-NH-PMIDA reached equilibrium within two hours and showed a maximum Langmuir adsorption capacity of 86.21 mg/g at optimum pH 4.8. Selective adsorption tests were carried out with real acid mine drainage (AMD) collected from an abandoned mining site in northern Norway. The novel adsorbent selectively recovered over 80% of Eu from pH-adjusted real AMD at an optimum dosage of 0.8g/l. A Direct contact membrane distillation (DCMD)/adsorption hybrid system was then developed by suspending granulated SBA15-NH-PMIDA in the feed tank to remediate pH adjusted AMD. The system managed to concentrate Eu ions by over three folds to enable efficient selective recovery of Eu (over 90%), while uptake of other competing metals remained below 10%. SBA15-NH-PMIDA managed to retain over 90% of adsorption capacity over 10 regeneration cycles. The study revealed that, 193.2 g of EuCl3 with 99% purity can be recovered by treating 1000 m3 of AMD. Additionally, clean water recovered from the membrane system can be re used in mining activities to reduce water stress in arid regions.

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