Effective removal of Fe(II) impurity from rare earth solution using surface imprinted polymer

• A novel Fe2+-ionic imprinted polyamine functionalized silica gel adsorbent was prepared.
• The adsorption and recognition properties of IIP-PEI/SiO2 for Fe2+ were studied.
• The IIP-PEI/SiO2 possesses strong adsorption affinity, specific recognition ability, and excellent selectivity for Fe2+.

Rare earth is a very important resource. But, impurities, such as Fe2+, have great influence on the properties of rare earth material. In this paper, a novel Fe2+-ionic imprinted polyamine functionalized silica gel adsorbent was prepared by a surface imprinting technique for selective adsorption of Fe2+ from rare earth solution. Firstly, functional macromolecule polyethyleneimine (PEI) was grafted onto the surfaces of silica gel particles, and the PEI/SiO2 was formed. Secondly, the ionic imprinting process was carried out using Fe2+ ion as a template, and Cr3+ ionic imprinting polyamine IIP-PEI/SiO2 was prepared. The adsorption and recognition properties of IIP-PEI/SiO2 for Fe2+ were studied in detail, and the effects of main imprinting conditions, such as the amount of crosslinking agent and reaction time, on the adsorption property of the imprinted material IIP-PEI/SiO2 were examined. The experimental results showed that the IIP-PEI/SiO2 possesses strong adsorption affinity, specific recognition ability, and excellent selectivity for Fe2+. The adsorption capacity could reach to 0.334 mmol g−1, and relative selectivity coefficients to Pr3+ and Ce3+ are 23.25 and 18.42, respectively. Besides, the IIP-PEI/SiO2 was regenerated easily using diluted hydrochloric acid solution as eluent and IIP-PEI/SiO2 possesses better reusability.