Green carbothermal synthesis of magnetic Fe/Mn nanomaterials for efficient rare earth recovery: Adsorption performance, mechanism, and continuous-flow verification

Rare earth elements (REEs) have emerged as critical metallic resources in modern industries due to their unique physicochemical properties. However, rare earth elements are inevitably discharged into environments during mining operations, leading to impact the ecosystem and to loss rare earth elements. To address this, the carbonized Fe/Mn nanomaterials (C-Fe/Mn) were synthesized through green carbothermal reduction to achieve efficient recovery of rare earth elements. It can be seen that the maximum adsorption efficiencies of REEs by synthesized material were yttrium (Y(Ⅲ) 98.28 %), lanthanum (La(Ⅲ) 97.37 %), dysprosium (Dy(Ⅲ) 88.75 %), and ytterbium (Yb(Ⅲ) 77.27 %), respectively. Through advanced characterization, C-Fe/Mn's magnetic properties have been confirmed, which enables direct recovery from wastewater and easy separation in application. The results showed that the carbon coating provides additional active sites, thereby enhancing its adsorption capacity, while the presence of zerovalent iron lattice improves its stability. Therefore, its efficient adsorption of rare earth elements is mainly attributed to the combined effect of complexation and electrostatic force. Finally, column experiments demonstrated that rare earth elements can be effectively removed and desorbed by C-Fe/Mn under continuous flow, indicating its potential for practical application. Overall, this approach not only mitigates environmental pollution but also promotes resource recycling, offering dual economic and ecological benefits.