Neodymium removal and recovery from simulated NdFeB leachate using manganese ferrite nanoparticles

This study explores the use of manganese ferrite nanoparticles (MnFe 2 O 4 ) for the removal and recovery of neodymium (Nd) from aqueous solutions, focusing on their potential application in wastewater treatment and environmental remediation. Neodymium, a critical element for the high-technology and energy industries, is increasingly present in aquatic environments due to its widespread use in devices such as computers, electric vehicles, and wind turbines. Through a series of kinetic, equilibrium, and desorption tests, the study optimized key operational parameters using Response Surface Methodology. Equilibrium analyses revealed that the Nd removal at equilibrium (q e ) reached 8 mg/g, while the maximum sorption capacity (q m ) was determined to be 9.2 mg/g. The results demonstrated a high removal efficiency (up to 90 %) under optimal conditions, which included a nanoparticle dose of 1000 mg/L, an initial neodymium concentration of 20 μmol/L, pH 6, and no salinity. The material showed great potential for neodymium recovery from synthetic magnet solutions, with removal rates exceeding 70 %. Desorption tests confirmed complete recyclability of the sorbent. These findings highlight manganese ferrite nanoparticles as a promising and sustainable approach for neodymium recovery. • RSM was used to optimize Nd removal from contaminated waters. • Nanoparticle dose was the most influential factor in Nd recovery efficiency. • Nd removal reached 93 % in ultrapure water and 74.8 % in simulated magnet leachate. • Nd removal from leachate shows potential for industrial-scale applications. • 100 % Nd desorption obtained with 0.01 mol/L HNO 3 after 6 h.