High Sorption and Selective Extraction of Actinides from Aqueous Solutions

Computational Comparative Study of the Binding of Americium with N-Donor Ligands

The accessibility of multiple valence states of americium (Am) inspired redox-based protocols aimed at efficient separation of trivalent Am (Am3+) from trivalent lanthanides (Ln3+) alternative to the traditional liquid-liquid extraction. This requires an extensive understanding of the coordination chemistry of Am in its various accessible valence states in the aqueous phase. In this work, by means of DFT calculations, the coordination of AmIII-VI with five typical N-donor ligands, i.e., terpyridine (tpy), bispyrazinylpyridine (dpp), bistriazinylpyridine (BTP), bistriazinyl bipyridine (BTBP), and bistrazinyl phenanthroline (BTPhen), was studied in terms of energy and topological analysis. The results show that the exchange of aqua ligands of hydrated ions by N-donor ligands is an entropy-driven process and enthalpically unfavorable. Topological analysis suggests a distinct mechanism of BTP to modulate the redox potential of Am(III) in that BTP can assist the relay of the leaving electron of AmIII, while the other N-donor ligands can detain the oxidation of Am by offering their electron instead. This comparative study enriches our understanding of the coordination chemistry of high-valent Am with N-donor ligands and recommends the ligand design toward the modulation of redox potentials of hydrated Am(III) ions.

The Optimal Axis-Symmetrical Plasma Potential Distribution for Plasma Mass Separation

The mass separation of chemical element mixtures is a relevant task for numerous applications in the nuclear power industry. One of the promising approaches to solve this problem is plasma mass separation. In a recent study, the efficiency of plasma mass separation in a configuration with a potential well and a homogeneous magnetic field was experimentally demonstrated. This article examines the possibility of increasing the distance between the deposition regions of charged particles with different masses by varying the profile of the electric field potential. Such correlation can be considered as the control in a system of active particles. A cylindrical coordinate system is used. The electric field is axially symmetrical, and the magnetic field is directed along the axis of the symmetry. The corresponding mathematical problem was solved in a general way. The criteria for increasing the distance between the deposition areas of the “light” and “heavy” components of the mixture have been formulated. A high sensitivity of particle trajectories to the electric field potential in the region of the pericentres of the trajectories of charged particles was detected. Recommendations for the practical implementation of the optimal spatial separation of ion fluxes are proposed.