Removal of U(VI) from aqueous solution by layered cobalt-magnesium double hydroxide composite

Static adsorption experiments were conducted to examine the removal efficacy of U(VI) from aqueous solutions by the L-CMs and analyze the removal mechanism. L-CMs efficiently removed U(VI) from the aqueous solution under an adsorption time of 60 min, dosage of 0.4 g/L, and pH of 5.5 at room temperature, and the removal efficiency of U(VI) reached 94.59% with an initial U(VI) concentration of 10 mg/L. The adsorption process was fitted to the pseudo-second-order kinetic and Langmuir models, indicating that monolayer chemical adsorption occurred primarily.

The maximum adsorption capacity fitted using the Langmuir model, was 105.49 mg/g. Thermodynamic analysis revealed that U (VI) adsorption by L-CMs was endothermic. Structural characterization results showed that the primary mechanism involved the complexation of U(VI) by -OH, CO32- and ion exchange by Mg2+ and the presence of layered Co(OH)2 in the L-CMs, which potentially facilitated ion exchange.