Can contaminated waters or wastewater be alternative sources for technology-critical elements? The case of removal and recovery of lanthanides


Technology critical elements (TCE) are considered the vitamins of nowadays technology. Factors such as high demand, limited sources and geopolitical pressures, mining exploitation and its negative impact, point these elements as new emerging contaminants and highlight the importance for removal and recycling TCE from contaminated waters. This paper reports the synthesis, characterization and application of hybrid nanostructures to remove and recover lanthanides from water, promoting the recycling of these high value elements. The nanocomposite combines the interesting properties of graphite nanoplatelets, with the magnetic properties of magnetite, and exhibits good sorption properties towards La(III), Eu(III) and Tb(III). The sorption process was very sensitive to solution pH, evidencing that electrostatic interactions are the main binding mechanism involved. Removal efficiencies up to 80% were achieved at pH 8, using only 50 mg/L of nanocomposite. In ternary solution, occurred a preferential removal of Eu(III) and Tb(III). The equilibrium evidenced a rare but interesting behaviour, and as a proof-of-concept the recoveries and reutilization rates, at consecutive cycles, highlight the recyclability of the composite without loss of efficiency. This study evidences that surface charge and the number of active sites of the composite controls the removal process, providing new insights on the interactions between lanthanoids and magnetic-graphite-nanoplatelets.



subject category

Engineering; Environmental Sciences & Ecology


Afonso, EL; Carvalho, L; Fateixa, S; Amorim, CO; Amaral, VS; Vale, C; Pereira, E; Silva, CM; Trindade, T; Lopes, CB

our authors


This work was developed within the scope of the project CICECOAveiro Institute of Materials, FCT Ref. UID/CTM/50011/2019, financed by national funds through the FCT/MCTES. C.B. Lopes and S. Fateixa thanks the national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the UID/CTM/50011/2019 numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.

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