Diglycolamic Acid Functionalized CNTs for Preferential Selection of Eu(III) over Am(III) Ion: Density Functional Theoretical Modelling Validated by Experiments

We report the structure, bonding, energetic, and thermodynamic parameters of Eu³⁺ and Am³⁺ with diglycolamic acid functionalized CNTs at BP86 and B3LYP functional level of theory using SVP and TZVP basis set. The free energy of extraction, ΔG_ext, of Eu³⁺ and Am³⁺ was computed using standard thermodynamical procedure in conjunction with COSMO (conductor like screening model) model. The value of ΔG_ext for Eu³⁺ ion was found to be higher than that of Am³⁺ as observed in the extraction experiments. The HOMO-LUMO analysis indicates that Eu³⁺ ion is harder than Am³⁺ ion leading to stronger interaction with hard donor based DGA-CNT.