DOI: https://doi.org/10.55373/mjchem.v27i5.27

Keywords: Hyperaccumulators; ligand; ion-adsorption clay; rare earth elements

Abstract

Rare earth elements (REE) are used to manufacture smart electronics. Conventional extraction of REE using concentrated ammonium salt elevates ammonia-N and REE levels and degrades water quality. The impact of leaching agents on the dissociation of REE from the ion-adsorption clay (IAC) is crucial for the success of in-situ mining by the leaching process. Furthermore, native plants may hyperaccumulate REE. The leaching of IAC with leaching agents may further enhance REE uptake. The objectives of this review are to discuss various chemicals that have been used for leaching REE from IAC and to elucidate the mechanisms of action during the leaching process. The transport and distribution of REE in the biomass of hyperaccumulators are elucidated. The outcome of this review may produce new knowledge on the suitability of various leaching agents, their REE-complex formations, and the effect of REE-complexation on hyperaccumulator uptake. This research may provide a safe method for in-situ leaching of REE from a mining site and the safe removal of toxic elements from soil with a delicate ecosystem.