Abstract
Rare-earth elements (REEs) are essential in a wide range of applications including magnets and satellite technology, with demand driven by geopolitical factors. While multiple techniques exist for REE recovery including solvent extraction and selective precipitation, solid–liquid extraction offers key advantages in selectivity, scalability, and recyclability. N, N, N′, N′-tetraoctyl diglycolamide (TODGA) is a tridentate ligand widely used in solvent extraction, but the incorporation in a solid support to separate individual lanthanides from acid solutions remains largely unexplored. A novel TODGA-organosilica sorbent material was developed and tested to evaluate recovery of 17 elements (REEs and thorium) in terms of selectivity, kinetics, and equilibrium isotherms in 0.01 to 15.9 M nitric acid. Characterization of the new sorbent was performed before and after sorption using FTIR, XPS, and SSA techniques to help elucidate sorption mechanisms and limiting variables. REE adsorption increased from 1.26 mg g−1 to 10 mg g−1 with nitric acid concentrations of 0.01 M and 15.9 M, respectively. TODGA-organosilica exhibits high selectivity towards heavy REEs (Dy to Lu), with minimal sorption of lighter REEs (Ce to Gd). Batch adsorption experiments confirm pseudo-second-order kinetics and a Langmuir adsorption isotherm with TODGA binding to REEs in a 3:1 complex. A packed bed column study confirmed the high selectivity of TODGA-impregnated organosilica towards heavy REEs and a proof-of concept experiment with coal fly ash leachate shows high selectivity for REEs over Al, Fe, and Ca present in several orders of magnitude higher concentrations. Fractionation was observed where loading cycle effluent contained 84 % light REEs while strip cycle effluent contained 80 % heavy REEs. More than 90 % of loaded REEs were successfully stripped with water as the stripping agent.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
