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Redox-mediated electrochemical liquid–liquid extraction for selective metal recovery

Nature Chemical Engineering volume 1, pages 281–292 (2024)Cite this article

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Abstract

Electrochemical separations are powerful platforms for the sustainable recovery of critical elements, environmental remediation and downstream processing. However, the recent development of electroseparations has primarily focused on heterogeneous adsorbents, which face the challenge of intermittent electroswing operation. Here we present a redox-mediated electrochemical liquid–liquid extraction separation platform that translates selective single-site binding to a fully continuous separation scheme. A redox-active extractant is molecularly designed with controllable hydrophobicity to maximize organic phase retention. The redox flow design enables fully electrified continuous operation with no external chemical input, achieving the selective recovery of precious metals from multicomponent streams. We demonstrate an atomic efficiency of over 90% and over 100:1 selectivity for practical critical metal leach streams, and 16-fold up-concentration for gold and platinum group metals from varied feedstocks including electronic waste, catalytic converter waste and mining streams. Our work is envisioned as a pathway towards a broader class of industrially applicable liquid–liquid extraction-based electrochemical separations.

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Fig. 1: Overview of the e-LLE platform.
Fig. 2: Design of the redox-active extractant and electrochemical characterization.
Fig. 3: Single-metal e-LLE performance and mechanistic investigation.
Fig. 4: Continuous-flow design and performance of e-LLE system.
Fig. 5: Performance of the e-LLE system for practical feedstocks.
Fig. 6: Techno-economic analysis of the e-LLE system.

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All data are available within the paper and the Supplementary Information. Source data are provided with this paper.

References

  1. Srimuk, P., Su, X., Yoon, J., Aurbach, D. & Presser, V. Charge-transfer materials for electrochemical water desalination, ion separation and the recovery of elements. Nat. Rev. Mater. 5, 517–538 (2020).

    Article  CAS  Google Scholar 

  2. Alkhadra, M. A. et al. Electrochemical methods for water purification, ion separations and energy conversion. Chem. Rev. 122, 13547–13635 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Su, X. et al. Asymmetric Faradaic systems for selective electrochemical separations. Energy Environ. Sci. 10, 1272–1283 (2017).

    Article  CAS  Google Scholar 

  4. Kim, K., Raymond, D., Candeago, R. & Su, X. Selective cobalt and nickel electrodeposition for lithium-ion battery recycling through integrated electrolyte and interface control. Nat. Commun. 12, 6554 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. High, M. et al. Precursor engineering of hydrotalcite-derived redox sorbents for reversible and stable thermochemical oxygen storage. Nat. Commun. 13, 5109 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Li, X., Zhao, X. H., Liu, Y. Y., Hatton, T. A. & Liu, Y. Y. Redox-tunable Lewis bases for electrochemical carbon dioxide capture. Nat. Energy 7, 1065–1075 (2022).

    Article  Google Scholar 

  7. Liu, Y. Y., Ye, H. Z., Diederichsen, K. M., Van Voorhis, T. & Hatton, T. A. Electrochemically mediated carbon dioxide separation with quinone chemistry in salt-concentrated aqueous media. Nat. Commun. 11, 2278 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Cotty, S. et al. Electrochemical recycling of homogeneous catalysts. Sci. Adv. 8, eade3094 (2022).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Massen-Hane, M., Diederichsen, K. M. & Hatton, T. A. Engineering redox-active electrochemically mediated carbon dioxide capture systems. Nat. Chem. Eng. 1, 35–44 (2024).

    Article  Google Scholar 

  10. Wilcox, J. An electro-swing approach. Nat. Energy 5, 121–122 (2020).

    Article  Google Scholar 

  11. Kim, N., Elbert, J., Kim, C. & Su, X. Redox-copolymers for nanofiltration-enabled electrodialysis. ACS Energy Lett. 8, 2097–2105 (2023).

    Article  CAS  Google Scholar 

  12. Kim, N., Lee, J. & Su, X. Precision tuning of highly selective polyelectrolyte membranes for redox-mediated electrochemical separation of organic acids. Adv. Funct. Mater. 33, 2211645 (2023).

    Article  CAS  Google Scholar 

  13. Su, X., Chen, Z., St-Pierre, J. & Vasiljevic, N. Electrochemistry for recycling. Electrochem. Soc. Interface 30, 41–43 (2021).

    Article  Google Scholar 

  14. Chen, R., Sheehan, T., Ng, J. L., Brucks, M. & Su, X. Capacitive deionization and electrosorption for heavy metal removal. Environ. Sci. Water Res. Technol. 6, 258–282 (2020).

    Article  Google Scholar 

  15. Su, X. & Hatton, T. A. Redox-electrodes for selective electrochemical separations. Adv. Colloid Interface Sci. 244, 6–20 (2017).

    Article  CAS  PubMed  Google Scholar 

  16. Chen, R. L. et al. Structure and potential-dependent selectivity in redox-metallopolymers: electrochemically mediated multicomponent metal separations. Adv. Funct. Mater. 31, 2009307 (2021).

    Article  CAS  Google Scholar 

  17. Kim, K. et al. Electrochemical approaches for selective recovery of critical elements in hydrometallurgical processes of complex feedstocks. iScience 24, 102374 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Candeago, R. et al. Semiconducting polymer interfaces for electrochemically assisted mercury remediation. ACS Appl. Mater. Interfaces 12, 49713–49722 (2020).

    Article  CAS  PubMed  Google Scholar 

  19. Cotty, S. R., Kim, N. & Su, X. Electrochemically mediated recovery and purification of gold for sustainable mining and electronic waste recycling. ACS Sustain. Chem. Eng. 11, 3975–3986 (2023).

    Article  CAS  Google Scholar 

  20. Guo, Z.-Y. et al. Development of electrochemical lithium extraction based on a rocking chair system of LiMn2O4/Li1–xMn2O4: self-driven plus external voltage driven. Sep. Purif. Technol. 259, 118154 (2021).

    Article  CAS  Google Scholar 

  21. Xu, T. & Huang, C. Electrodialysis-based separation technologies: a critical review. AlChE J. 54, 3147–3159 (2008).

    Article  CAS  Google Scholar 

  22. Brown, C. G. & Sherrington, L. G. Solvent extraction used in industrial separation of rare earths. J. Chem. Technol. Biotechnol. 29, 193–209 (1979).

    Article  CAS  Google Scholar 

  23. El-Nadi, Y. A. Solvent extraction and its applications on ore processing and recovery of metals: classical approach. Sep. Purif. Rev. 46, 195–215 (2017).

    Article  CAS  Google Scholar 

  24. Mooiman, M. B. The solvent extraction of precious metals: a review. In Proc. 17th International Precious Metals Conference 411–434 (International Precious Metals Institute, 1993).

  25. Yordanov, A. T. & Roundhill, D. M. Solution extraction of transition and post-transition heavy and precious metals by chelate and macrocyclic ligands. Coord. Chem. Rev. 170, 93–124 (1998).

    Article  CAS  Google Scholar 

  26. Mahandra, H., Faraji, F. & Ghahreman, A. Novel extraction process for gold recovery from thiosulfate solution using phosphonium ionic liquids. ACS Sustain. Chem. Eng. 9, 8179–8185 (2021).

    Article  CAS  Google Scholar 

  27. Towler, G. & Sinnott, R. in Chemical Engineering Design 3rd edn (eds Towler, G. & Sinnott, R.) 631–733 (Butterworth-Heinemann, 2022).

  28. Kislik, V. S. in Solvent Extraction (ed. Kislik, V. S.) 113–156 (Elsevier, 2012).

  29. Vidal, O. in Mineral Resources and Energy (ed. Vidal, O.) 27–52 (Elsevier, 2018).

  30. Sovacool, B. K. et al. Sustainable minerals and metals for a low-carbon future. Science 367, 30–33 (2020).

    Article  CAS  PubMed  Google Scholar 

  31. Butt, C. R. M. & Hough, R. M. Why gold is valuable. Elements 5, 277–280 (2009).

    Article  CAS  Google Scholar 

  32. Murphy, K. Gold RRS 2022—Surge in recent discoveries. S&P Global Market Intelligence https://www.spglobal.com/marketintelligence/en/news-insights/research/gold-rrs-2022-surge-in-recent-discoveries (2022).

  33. Calvo, G., Mudd, G., Valero, A. & Valero, A. Decreasing ore grades in global metallic mining: a theoretical issue or a global reality? Resources 5, 36 (2016).

    Article  Google Scholar 

  34. Moreau, V., Dos Reis, P. C. & Vuille, F. Enough metals? Resource constraints to supply a fully renewable energy system. Resources 8, 29 (2019).

  35. Cui, J. R. & Zhang, L. F. Metallurgical recovery of metals from electronic waste: a review. J. Hazard. Mater. 158, 228–256 (2008).

    Article  CAS  PubMed  Google Scholar 

  36. Zadra, J. B., Engel, A. L. & Heinen, H. J. Process for Recovering Gold and Silver from Activated Carbon by Leaching and Electrolysis (US Department of the Interior, Bureau of Mines, 1952).

  37. Ford, P. et al. Economics of end-of-life materials recovery: a study of small appliances and computer devices in Portugal. Environ. Sci. Technol. 50, 4854–4862 (2016).

    Article  CAS  PubMed  Google Scholar 

  38. Beyuo, M. & Abaka-Wood, G. ZADRA elution circuit optimisation and operational experience at the CIL Plant of Gold Fields Ghana Limited. In Proc. 4th UMaT Biennial International Mining and Mineral Conference 161–167 (UMaTBIC, 2016).

  39. Cutting cobalt. Nat. Energy 5, 825 (2020).

  40. Babu, B. R., Parande, A. K. & Basha, C. A. Electrical and electronic waste: a global environmental problem. Waste Manag. Res. 25, 307–318 (2007).

    Article  CAS  Google Scholar 

  41. Ding, Y. J. et al. Recovery of precious metals from electronic waste and spent catalysts: a review. Resour. Conserv. Recycl. 141, 284–298 (2019).

    Article  Google Scholar 

  42. Yu, M. L., Wang, K. & Vredenburg, H. Insights into low-carbon hydrogen production methods: green, blue and aqua hydrogen. Int. J. Hydrog. Energy 46, 21261–21273 (2021).

    Article  CAS  Google Scholar 

  43. Shestakova, M. & Sillanpää, M. Removal of dichloromethane from ground and wastewater: a review. Chemosphere 93, 1258–1267 (2013).

    Article  CAS  PubMed  Google Scholar 

  44. Priya, V. S. & Philip, L. Treatment of volatile organic compounds in pharmaceutical wastewater using submerged aerated biological filter. Chem. Eng. J. 266, 309–319 (2015).

    Article  CAS  Google Scholar 

  45. Toth, A. J. et al. Novel method for the removal of organic halogens from process wastewaters enabling water reuse. Desalin. Water Treat. 130, 54–62 (2018).

    Article  CAS  Google Scholar 

  46. Alder, C. M. et al. Updating and further expanding GSK’s solvent sustainability guide. Green Chem. 18, 3879–3890 (2016).

    Article  CAS  Google Scholar 

  47. Larsen, C. et al. A tool for identifying green solvents for printed electronics. Nat. Commun. 12, 4510 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Lu, P. Y. & Alkire, R. C. Mass transfer in parallel plate electrolyzers with two‐phase liquid‐liquid flow. J. Electrochem. Soc. 131, 1059 (1984).

    Article  CAS  Google Scholar 

  49. Alkire, R. & Köhler, J. Indirect electrochemical epoxidation of hexene in a liquid-liquid electrolyte. J. Appl. Electrochem. 18, 405–409 (1988).

    Article  CAS  Google Scholar 

  50. Papageorgiou, N., Maier, W. F. & Grätzel, M. An iodine/triiodide reduction electrocatalyst for aqueous and organic media. J. Electrochem. Soc. 144, 876 (1997).

    Article  CAS  Google Scholar 

  51. Masahiro, T., Akitsugu, O. & Taijiro, O. The chemical behavior of low valence sulfur compounds. VIII. The oxidation of sodium thiosulfate with ozone. Bull. Chem. Soc. Jpn 46, 3785–3789 (1973).

    Article  Google Scholar 

  52. Rumble, J. R. CRC Handbook of Chemistry and Physics (CRC Press, 2017).

  53. Sarla, M., Pandit, M., Tyagi, D. K. & Kapoor, J. C. Oxidation of cyanide in aqueous solution by chemical and photochemical process. J. Hazard. Mater. 116, 49–56 (2004).

    Article  CAS  PubMed  Google Scholar 

  54. Pei, Z. B. et al. Review of the I−/I3− redox chemistry in Zn-iodine redox flow batteries. Mater. Res. Bull. 141, 111347 (2021).

    Article  CAS  Google Scholar 

  55. Li, X. et al. Symmetry-breaking design of an organic iron complex catholyte for a long cyclability aqueous organic redox flow battery. Nat. Energy 6, 873–881 (2021).

    Article  CAS  Google Scholar 

  56. Orita, A., Verde, M. G., Sakai, M. & Meng, Y. S. A biomimetic redox flow battery based on flavin mononucleotide. Nat. Commun. 7, 13230 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  57. Geankoplis, C. J., Hersel, A. A. & Lepek, D. H. Prentice Hall International Series in the Physical and Chemical Engineering Sciences (Prentice Hall, 2018).

  58. Baker, D. A., East, G. C. & Mukhopadhyay, S. K. Synthesis and characterization of some disulfonyl azides as potential crosslinking agents for textile fibers. J. Appl. Polym. Sci. 79, 1092–1100 (2001).

    Article  CAS  Google Scholar 

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Acknowledgements

This paper is based on work supported by the US Department of Energy, Office of Basic Energy Sciences under award no. DOE DE-SC0021409. This work is also partially supported by the NSF DMREF grant 2323988.

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Authors and Affiliations

  1. Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA

    Stephen R. Cotty, Aderiyike Faniyan, Johannes Elbert & Xiao Su

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Contributions

S.R.C., A.F., J.E. and X.S. conceptualized and designed this work. S.R.C. and A.F. performed the experiments. S.R.C. and X.S. wrote the original paper. X.S. supervised the work and secured the funding. All authors analyzed the data and edited the paper.

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Correspondence to Xiao Su.

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The authors have applied for a provisional patent based on the technology proposed in the paper.

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Cotty, S.R., Faniyan, A., Elbert, J. et al. Redox-mediated electrochemical liquid–liquid extraction for selective metal recovery. Nat Chem Eng 1, 281–292 (2024). https://doi.org/10.1038/s44286-024-00049-x

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