Graphene Oxide Caged Biopolymer Nanocomposite for Purification of Rare Earth Elements from High Grade Egyptian Monazite Concentrate

Rare earth elements (REEs) play a critical role in the applications of advanced materials. In this respect, an eco-friendly calcium/alginate-graphene oxide (Ca/Alg–GO) nanocomposite was prepared for the removal of Th(IV), U(VI) and Fe(III) from rare earth chloride (RECL3) liquor. The high specific surface area and large numbers of oxygen-containing functional groups of GO and alginate make them suitable for the separation of different metal ions. Results obtained from this work showed that the adsorption process was pH dependent where at pH 2.0 selective removal of Th(IV), U(VI) and Fe(III) was achieved with no separation for REEs. Maximum adsorption capacities for Th(IV), U(VI) and Fe(III) using Ca/Alg–GO nanocomposite reached 418.0 mg g−1, 129.0 mg g−1, and 139.0 mg g−1; respectively. Equilibrium isotherm data were best described by Langmuir model exhibiting R2 value of 0.92, 0.96 and 1.00 for Th(IV), U(VI) and Fe(III); respectively. In order to produce impurities-free RECL3 liquor, three consecutive cycles were required to completely remove Th(IV), U(VI) and Fe(III) from the said liquor.