Highly efficient extraction of rare earth elements and others ions from green phosphoric acid medium using TMSEDTA@GO@Fe3O4 core-shell

Abstract

Tunisian industries process enormous quantity of green phosphoric acid. The latter contains significant amounts of rare earth elements. This work highlights the extraction of numerous rare earth elements from concentrated green phosphoric acid solutions based on core-shell graphene oxide@Fe3O4 (GO@Fe3O4) nanoparticles, prepared by a simple and cost-effective method, and functionalized by N-(trimethoxysilylpropyl) ethylenediamine triacetic acid (TMSEDTA). The as-synthetized and functionalized cor-shell materials were fully characterized through several techniques to assess their morphology, size and crystallinity. Raman spectroscopy, FTIR and X-ray Photoelectron Spectroscopy were used to identify their chemical composition, while Inductively Coupled Plasma Optical Emission Spectrometry was used to determine the concentration of rare earth elements before and after the extraction process. TMSEDTA@GO@Fe3O4 particles exhibited a high efficiency to uptake the rare earth elements present in the concentrated phosphoric acid medium. In addition, thanks to the ferromagnetic properties of the particles and to the corrosion-resistant graphene oxide layer, the earth metal uptake procedure, by a magnet, from concentrated phosphoric acid is very simple. These promising results which are based on a straightforward process might be beneficial to industrial phosphoric acid manufacturers for extracting rare earths from concentrated acid.