The influence of vanadate in calcined Mg/Al hydrotalcite synthesis on adsorption of vanadium (V) from aqueous solution

Calcined Mg/Al hydrotalcite (CH-Mg/Al) and calcined Mg/Al vanadate hydrotalcite (CHV-Mg/Al) were prepared and characterized. Adsorption kinetics, effect of pH, equilibrium isotherms and the selectivity of both absorbents were assessed. The removal mechanism was studied by XRD, XPS and FTIR. The results showed that there was no redox reaction during the adsorption process. The adsorption process of CH-Mg/Al was mainly anion exchange and adsorption on external surface of the layers. The adsorption capacity of CHV-Mg/Al was mainly caused by ion exchange. The calcined Mg/Al hydrotalcite showed wonderful vanadium (V) adsorption capacity. Using vanadate to synthesize hydrotalcite was unfavorable to removal of vanadium (V) from aqueous solution. CHV-Mg/Al had highly selectivity of vanadium (V) in the mixed solution of vanadate and dichromate. Calcined hydrotalcites material has potential application for the removal of vanadium (V) from aqueous solution.

► CHV-Mg/Al showed selectivity of vanadium (V) while CH-Mg/Al did not.
► Adsorption mechanism of vanadium (V) onto CH-Mg/Al and CHV-Mg/Al
► CHV-Mg/Al had both ion and structure memory effect during the adsorption process.
► Calcined hydrotalcites material may be a promising adsorbent for removal of V (V).