Construction of ion-imprinted nanofiber chitosan films using low-temperature thermal phase separation for selective and efficiency adsorption of Gd(III)

Abstract

Rare earth elements are a treasure trove of new materials in the twenty-first century, however, the similar radii of the lanthanide metals make it difficult for the ionic rare earth elements to be selectively separated. Ion-imprinted technology can help to selectively separate rare earth elements, nevertheless, most materials used for ion-imprinted are expensive. Chitosan has a wide range of sources, low cost, and a large quantity of amino and hydroxyl groups, which is advantageous for adsorbing heavy metals. Most scholars have made chitosan into a shape such as microspheres, which does not exert the great value of chitosan and is difficult to recycle, which greatly affects the adsorption rate. There are few studies on increasing the specific surface area of chitosan, so there is still much room for improvement in the adsorption capacity of chitosan. In order to improve the performance of chitosan-based materials, this research reports the preparation of imprinted nanofiber chitosan films (INFCF) by ion-imprinted technique and low-temperature thermal phase separation. These methods not only make the material have a high BET surface area, but also enable the material to have selective adsorption capacity. The BET surface area of the film is 203.6 m2 g−1. The maximum adsorption capacity of INFCF for Gd(III) was 71.00 mg g−1 at pH 7.0. The adsorption mechanism is summarized as a single layer of chemical adsorption. The excellent selectivity and repeatability of INFCF make it a high-quality material for the selective recovery of rare earth ions in industrial production.