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Mika Erik Tapio Sillanpää

Selectively capacitive recovery of rare earth elements from aqueous solution onto Lewis base sites of pyrrolic-N doped activated carbon electrodes

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  • Feiping Zhao, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
  • ,
  • Shixing Chen, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
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  • Hongrui Xiang, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
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  • Tianyu Gao, Central South University, National Engineering Research Center for Heavy Metals Pollution Control and Treatment
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  • Danyang Wang, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
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  • Dun Wei, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
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  • Mika Sillanpää
  • Yong Ke, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
  • ,
  • Chong Jian Tang, Central South University, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution

The growing demand for rare earth elements (REEs) necessitates cheap and environmentally friendly technologies for REEs recovery. Herein, we fabricated a pyrrolic-N doped activated carbon electrode (PPyN-AC) via two facile steps of in-situ polymerization of pyrrole monomers and further carbonization. Capacitive deionization (CDI) using PPyN-AC as electrodes is the first time applied for REEs capture from aqueous solution. PPyN-AC possesses a high N doping rate (9.55 at.%) and excellent capacitance (128.98 F/g). The CDI flow-by tests shows that the electrosorption capacity of La(III) by PPyN-AC electrode was 23.66 mg/g within 25 min at optimal conditions. The rapid and efficient La(III) electrosorption performance is attributed to the pyrrole-N configuration in the carbon matrix. Beyond that, the PPyN-AC electrode could selectively capture La(III) from a quaternary-component system of La(III), Fe(III), Ca(II) and Na(I) in aqueous solution. The REE selectivity mechanism, which involves the ionic charge, hydrated radii of metal ions, and hard-soft Lewis acid-base principle, was proposed. Overall, this work demonstrates a new efficient approach for the selective recovery of REEs from aqueous solution with minimal land and energy demands.

Original languageEnglish
JournalCarbon
Volume197
Pages (from-to)282-291
Number of pages10
ISSN0008-6223
DOIs
Publication statusPublished - Sep 2022

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd

    Research areas

  • Capacitive deionization, Electrosorption, N-doped active carbon, Rare earth elements, Selectivity

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