Selective exchange of alkali metal ions on EAB zeolite

EAB zeolite was successfully prepared and applied to selective adsorption of Li + , Na + and K + ions. The physical and chemical properties of the adsorbent were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope (SEM) and thermogravimetry (TG) methods. The ion exchange behaviours for Li + , Na + and K + ions in monomcomponent and multicomponent solutions were studied. In independent ion exchange, the ion exchange capacities ratios α (Na/Li) and α (K/Li) were 3.8 and 6.2, respectively. In competitive ion exchange, the selectivities β (Na/Li) and β (K/Li) increased with the initial concentrations and reached 409 and 992 when the initial concentrations was 100 mmol/L. The thermodynamic study results showed that Gibbs free energy change (Δ G Θ ) of ion exchange reaction between Li-EAB and K + was −34.96 kJ/mol, indicating that ion exchange of K + ions was more energetically favourable than Li + ions. The calculation results showed that the energy barriers of ion exchange increased in the order K +  < Na +  < Li + . The study shows that EAB zeolite is potential to be used in the separation of alkali ions.