Facile fabrication of boron doped magnetic calcium phosphate nanocomposite for potential adsorption of samarium ions: equilibrium, kinetic, and thermodynamic studies

The recovery of rare-earth elements (REEs) from waste water streams has emerged as a pressing concern, driven by both escalating environmental degradation and growing economic demand. This study used a boron-doped magnetic calcium phosphate composite (BMCP) to adsorb or remove samarium ions, which are a member of the lanthanides class, from an aqueous media. Using Elovich, intraparticle diffusion, pseudo-first-order and pseudo-second-order equations, the dominating mechanism was empirically investigated based on the kinetic data. It was found that the adsorption process take place according to adiffusion mechanism governed by interactions between Sm(III) ions and MBCP function groups. Langmuir model fitted the equilibrium data with a maximum theoretical capacity of 271.03 mg g−1. The enthalpy (ΔHo) and entropy (ΔSo) of Sm(III) adsorption onto BMCP were calculated to be 9.31 (kJ.mol−1) and −0.018 (kJ.mol−1K−1), respectively. The influence of competing metal ions, including Cr(VI), Mn(II), Co(II), Ni(II), and Sr(II), on the adsorption efficiency of lanthanides ions (La(III), Ce(III), Sm(III), and Eu(III)) was investigated. Cost analysis of (BMCP) treatment indicates a projected expenditure of US$0.37 for the removal of 1000 mg/L samarium from waste water. The findings presented herein indicate that BMCP composite exhibit significant potential as an adsorbent for the removal and separation of rare earth ions from aqueous solution.