resumo
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.
palavras-chave
RARE-EARTH-ELEMENTS; MUNICIPAL SOLID-WASTE; GRAPHITE NANOPLATELETS; MAGNETITE PARTICLES; RHINE RIVER; NANOCOMPOSITES; ADSORPTION; COMPOSITE; INCINERATORS; FABRICATION
categoria
Engineering; Environmental Sciences & Ecology
autores
Afonso, EL; Carvalho, L; Fateixa, S; Amorim, CO; Amaral, VS; Vale, C; Pereira, E; Silva, CM; Trindade, T; Lopes, CB
nossos autores
Carlos Amorim
Investigador Auxiliar
Carlos Manuel Silva
Professor associado
Cláudia Batista Lopes
Investigador Auxiliar
Sara Fateixa
Investigador Júnior
Tito Trindade
Professor Catedrático
Vitor Brás Sequeira Amaral
Professor CatedráticoGrupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G4 - Materiais Renováveis e Economia Circular
G6 - Materiais Virtuais e Inteligência Artificial
agradecimentos
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.