Nitrogen-Enriched Porous Benzimidazole-Linked Polymeric Network for the Adsorption of La (III), Ce (III), and Nd (III)

A porous benzimidazole-linked polymer, synthesized by a microwave-assisted procedure, exhibits an adsorption capacity of 760 mg/g, 700 mg/g, and 840 mg/g, respectively, for three rare earth ions, La (III), Ce (III), and Nd (III). The synthesized BINP polymer has an average pore size of 90 Å, a total pore volume of 0.03 cm 3 /g and a surface area of 21 m 2 /g. The electrostatic interaction between the positively charged polymer and the negatively charged rare-earth ions is responsible for the adsorption process, which is governed by the Langmuir or Freundlich isotherm. Adsorbed metal ions can be easily dissociated from the polymer, enabling polymer reusability with high recovery and efficiency.