@article{10902/35517,
year = {2025},
month = {4},
url = {https://hdl.handle.net/10902/35517},
abstract = {High-charge micas exhibit improved adsorption properties and are a promising alternative clay material for the engineered barrier in deep geological repositories. When combined with Eu3+ cations, they serve as an in situ luminescent probe for tracking the physical–chemical changes occurring in this engineered barrier over the long term. Therefore, a better understanding of the local environment of the lanthanide is highly desirable to comprehend the specific behavior of these systems. A combination of different techniques, (X-ray diffraction, thermogravimetry, fluorescence, and X-ray absorption spectroscopy), has allowed the study of the local environment of two luminescent lanthanide cations, Eu3+ and Gd3+, embedded in the galleries of two high-charge micas with different Si/Al tetrahedral ratio. The results show that the hydration state of these cations is primarily influenced by the layer charge of the aluminosilicate, and secondarily by the cation’s hydration enthalpy. High-charge micas doped with trivalent lanthanide cations are more hydrated compared to the original clays with Na+ in the interlayer. Nevertheless, both Eu3+ and Gd3+ are adsorbed as inner-sphere complexes in the galleries of high-charge micas. They are located inside the distorted hexagonal cavity in all cases, coordinated by 3 oxygens from the tetragonal sheet, one fluorine from the octahedral sheet, and by 2–4 oxygens from water molecules, all at distances around 2.4 Å. An additional oxygen atom at a distance of 3.45–3.50 Å, is proposed from an H2O molecule in the second coordination shell.},
organization = {This work has been supported by the Spanish Ministerio de Ciencia e Innovación, Project ref. TED2021-131305B-I00 financed by MCIN/ AEI /10.13039/501100011033 and by the European Union-NextGenerationEU/PRTR. We would like to thank IDIVAL, Project INNVAL19/18 for financial support. M. T. Candela acknowledges the predoctoral grant “Concepción Arenal” (University of Cantabria- Government of Cantabria). The authors thank Diamond Light Source for beamtime (proposal SP19223-1) and financial support and the I20-Scanning beamline staff for all the assistance received.},
publisher = {Elsevier},
publisher = {Journal of Colloid and Interface Science, 2025, 684(1), 552-565},
title = {Adsorption of Eu3+ and Gd3+ on high-charge micas as inner-sphere complexes},
author = {Candela de Aroca, Marina Teresa and Martín Rodríguez, Rosa and Díaz Moreno, Sofía and Valiente Barroso, Rafael and Aguado Menéndez, Fernando and Perdigón Aller, Ana Carmen},
}