New Inorganic (an)ion Exchangers Based on (alkoxide-free) Sol- Gel Generated Layered Mg-al Hydrous Oxides for Target Anions (arsenate, Arsenite, Fluoride, Bromide, Bromate, Selenate) Removal

In water treatment, adsorption & ion exchange are usually used on the stage of deep purification when higher selectivity to toxic molecules and ions is needed. Inorganic ion exchangers are that class of the adsorptive materials which, if developed by the advanced synthesis approaches, are capable to lower the concentrations of target anions up to the level requesting by World Health Organization (WHO). This paper shows: (1) the new non-traditional sol-gel synthesis of double layered hydrous oxides of Mg-Al comparing them to the previously developed layered Zn-Al and bulk Fe-Al oxides, (2) structure characterization of the Mg-Al hydrous oxides by XRD, N2 adsorption, SEM, FTIR, and assessment of their surface chemical properties by XPA and potentiometric titration, (3) adsorption isotherms and kinetics of H2AsO4 uptake by the new Mg-Al hydrous oxides and adsorptive removal of the other toxic anions: F , Br , BrO3 , HSeO4 , As(III), as well as, (4) mechanism of H2AsO4 by FTIR, EXAFS and XPS.