Selective extraction of gadolinium using free-standing imprinted mesoporous carboxymethyl chitosan films with high capacity

Novel imprinted mesoporous carboxymethyl chitosan films (IMCFs) were investigated in detail. When acting as adsorbents, imprinted mesoporous carboxymethyl chitosan films with highly ordered chiral nematic structures, exhibit efficient adsorption for gadolinium ions (Gd(III)). The maximum adsorption capacity of IMCFs calculated from Langmuir isotherm model was 25.372 mg g−1 at pH 7.0. Due to the presence of highly selective imprinted sites, chitosan films possess significant selectivity for Gd(III), compared with other rare earth ions. More importantly, carboxymethyl chitosan films could be retrieved conveniently and quickly without extra operations, which greatly promote their recycling. Reusability tests further demonstrated films can be considered as stable and reliable adsorbents, enhancing their potential industrial applications.