High-efficiency enrichment of uranium(VI) from aqueous solution by hydromagnesite and its calcination products

The removal of uranium from aqueous solution by hydromagnesite and its calcination products was investigated. Through the study, we found that the adsorption capacities of hydromagnesite, magnesium carbonate and magnesium oxide for uranium could reach 342.96, 493.79, 2154.14 mg g^-1, respectively. The high temperature will reduce the activity of magnesium oxide, resulting in the adsorption capacity decrease. The results indicate that the optimum pH for the heat-treated samples was 3.0-4.5 and for hydromagnesite 6.0-7.0. Thermodynamic parameters such as ∆G, ∆H and ∆S, indicated that the adsorption processes are spontaneous and endothermic. (author)