abstract
An acidic aqueous biphasic system (AcABS) presenting a desired and reversible phase transition with HNO3 concentration and temperature was developed herein as an integrated platform for metal separation. The simple, economical, and fully incinerable (C,H,O,N) AcABS composed of tetrabutylammonium nitrate ([N-4444][NO3])+HNO3+H2O was characterized and presented an excellent selectivity towards Ce-IV against other rare earth elements and transition metals from both synthetic solutions and nickel metal hydride (NiMH) battery leachates. The acid-driven self-assembly of AcABS bridges the gap between traditional ABS and liquid-liquid extraction whilst retaining their advantageous qualities, including compatibility with highly acidic solutions, water as the primary system component, the avoidance of organic diluents, rapid mass transfer, and the potential integration of the leaching and separation steps.
keywords
RARE-EARTH-ELEMENTS; IONIC-LIQUID; TETRAVALENT CERIUM; CRYSTAL-STRUCTURE; MULTINUCLEAR SPECIATION; REDOX CHEMISTRY; FORCE-FIELD; NITRIC-ACID; EXTRACTION; NITRATE
subject category
Chemistry, Multidisciplinary; Green & Sustainable Science & Technology
authors
Schaeffer, N; Vargas, SJR; Passos, H; Brandao, P; Nogueira, HIS; Svecova, L; Papaiconomou; Coutinho, JAP
our authors
Helena Isabel Seguro Nogueira
Assistant Professor with Aggregation
Helena Isabel Sousa Passos
Junior Researcher
Nicolas Schaeffer
Assistant Researcher
Paula Cristina Ferreira da Silva Brandão
Assistant Researcher
Sílvia Juliana Rodriguez Vargas
Post-Doc Fellowshipacknowledgements
The authors thank Maria C. C. Azevedo and Marcia C. Neves for help with the Raman and SEM data acquisition, respectively. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Foundation for Science and Technology/MCTES. N.S. acknowledges the national funds (OE), through FCT Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the 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. H. Passos acknowledges FCT under the Scientific Employment Stimulus-Individual CallCEECIND/00831/2017.