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(ΔGΘ) 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.