Functionalized adsorbents for the recovery of rare earth elements from aqueous media

An adsorbent comprising:

• a substrate comprising sulfonated polystyrene having an amine derived from diamine functionalization of imidoacetate moieties,
• wherein the substrate is acid and base resistant;
• and
• a material having at least one carboxyl group and a plurality of anhydride groups attached to a surface of the substrate through an amide bond between the carboxyl group on the material and the amine on the substrate,
• wherein the anhydride groups hydrolyze to form additional carboxyl groups in an aqueous environment,
• wherein the material selectively binds with at least one rare earth element in an aqueous solution via at least one additional carboxyl group on the surface-bound material.

An adsorbent for use in an aqueous environment comprising:

• a substrate consisting of polystyrene functionalized with an amine, and
• a material attached to a surface of the substrate through an amide bond between a single carboxyl group on the material and a single amine on the surface of the substrate,
• wherein the material comprises a plurality of anhydride functional groups,
• wherein the material selectively binds with at least one rare earth element via at least one additional carboxyl group formed on the surface-bound material from the anhydride functional groups in the aqueous environment.