LDH(Mg/Al:2)@montmorillonite nanocomposite as a novel anion-exchanger to adsorb uranyl ion from carbonate-containing solutions

A layered double hydroxide@montmorillonite nanocomposite (LDH@MMT) was synthesized by the coating of growing LDH layers onto the MMT surface through hydrothermal method and used to remove uranyl ion from carbonate-containing aqueous solutions. The adsorption kinetics was described using a pseudo-second-order model and the adsorption isotherms data was successfully explained by the Langmuir model. The adsorption capacity of MMT was considerably enhanced from 16 to more than 55 mg g^-1 after coating of LDH at a wide range of pH (3-11). The synthesized hybrid adsorbent showed a higher affinity toward UO₂(CO₃)₂^2- and UO₂(CO₃)₃^4- species. These findings herein propose that LDH@MMT nanocomposite is a potential and proper adsorbent for the removal of U(VI) from natural and polluted waters. (author)