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 N 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).