Preparation of ion imprinted EDTA modified chitosan-magnetic graphene oxide for selective recovery and adsorption mechanism of Ce(III)

Selective recovery of rare earth elements (REEs) from environmental waste is strategically significant. Herein, Ce(III) imprinted EDTA modified chitosan-magnetic graphene oxide (IIP-EDTA-CS-MGO) was prepared for selective recovery of Ce(III). Furthermore, adsorption mechanism was clarified based on versatile adsorption fittings and spectroscopic tests. Result presents, adsorption reaches its peak at pH = 7 in 25 min with maximum adsorption capacity 353.28 mg·g^-1. Functional groups C(=O)NH, CN and C-O-C in IIP-EDTA-CS-MGO provide heterogeneous affinity for Ce(III) to induce chemical adsorption. Thermodynamic calculation suggests spontaneous, endothermic and entropy increasing adsorption. Owing to Ce(III) imprinting, IIP-EDTA-CS-MGO demonstrates selectivity coefficients 3.09, 3.19, 14.10, 12.65 towards Ce(III) for binary solutions Ce/Eu, Ce/Dy, Ce/Cu, Ce/Cr, respectively. By virtue of its paramagnetic property, IIP-EDTA-CS-MGO can be readily recovered via magnetic separation for cyclic adsorption, thereby retaining adsorption quantity 116.58 mg·g^-1 for Ce(III) in five consecutive cycles. This work provides a new approach for fabricating magnetic bio-adsorbent towards selective recovery of Ce(III).