Surface magnetized MgAl-LDHs and MgAl-LDO with excellent adsorption capacity and convenient recovery for the removal of U(VI)

An inorganic adsorbent with conveniently recovery performance is attractive in the treatment of uranium-containing wastewater. Herein magnetic Mg-Al layered double hydroxide composites (Mag-LDHs) and its calcination compound, Mag-LDHs (Mag-LDO), have been successfully prepared. Their physicochemical characteristic was analyzed with XRD, SEM, XPS, VSM, FT-IR, TGA, Zeta potential and N₂ adsorption-desorption isotherms. The adsorption behavior of both adsorbents toward uranium were investigated. The solid-liquid separation could be conveniently achieved by external magnetic field. The maximum theoretical adsorption capacities toward U(VI) were 436.16 mg/g for Mag-LDHs and 317.71 mg/g for Mag-LDO. The adsorption capacity of Mag-LDHs and Mag-LDO retained 80.72% and 85.58% even undergoing five adsorption-desorption cycles. The study proposed Mag-LDHs and Mag-LDO as alternative uranium-specific adsorbents applicable in the acid wastewater (pH = 5.5). (author)