(185d) Preparation of Ion-Imprinted Mesoporous Silica Functionalized with Aspargine for Adsorption of Nd(III) from Phosphogypsum Waste

Rare earth elements (REEs) are critical materials for modern technological devices but are difficult to separate from one another because of their physical and chemical similarities. REE recovery from waste sources such as phosphogypsum (0.5% REEs) ensures their sustainable supply, realizes their efficient usage, and also curbs negative environmental impact. In this study, ion-imprinted mesoporous silica (IIMS) was developed for selective recovery of Nd³⁺ from phosphogypsum waste based on the supported material of ordered mesoporous silica SBA-15 with asparagine as a ligand and Nd(III) as a template. The prepared IIMS was characterized by Fourier transmission infrared spectrometry, X-ray diffraction, scanning electron microscope, nitrogen adsorption–desorption isotherm and thermogravimetric analysis. Results showed that the synthesized IIMS possessed high ordered mesoporous structure. Leaching of the Nd(III) template from the final IIMS showed that the maximum desorbed Nd(III) was 291 mg g^−1, hence its potential maximum adsorption capacity. The adsorption behaviour of Nd(III) on the synthesized aspargine-based IIMS was studied using batch experiments. Factors affecting the separation and recovery Nd(III) including solution pH, co-existing ions, kinetics, isotherms, regeneration and recyclability are currently under investigation.

This research was supported by the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT (No. 2017R1A2B2002109) and the Ministry of Education (No. 22A20130012051(BK21Plus)).