Fast and efficient adsorption of La³⁺by magnetic Fe₃O₄-modified HA/ NH₂-MCM-48 composites

Co-mixing of HA with NH2-MCM-48 to form a precipitate by wet synthesis method using NH2-MCM-48 as a substrate. Then Fe3O4 nanoparticles were composited with HA/NH2-MCM-48 by alcohol-thermal method to form HA/Fe3O4@NH2-MCM-48 composites, and the composites were characterized. Firstly, the adsorption performance of HA/Fe3O4@NH2-MCM-48 was discussed by adsorption experiments with the control HA/NH2-MCM-48 and NH2-MCM-48 at different influencing factors on the adsorption of La3+. Moreover, the adsorption types and adsorption mechanisms were investigated by isothermal adsorption modeling, kinetic modeling and thermodynamic modeling. In the end, the reusability and stability of the composites was evaluated by cyclic adsorption-desorption experiments. After five repetitive cycle experiments, the composites were able to maintain 82.9 % of the first adsorption amount. The results show that HA/Fe3O4@NH2-MCM-48 has good adsorption performance and magnetic properties for lanthanide ions, which is favorable for recycling. After optimization experiments, the adsorption amount and adsorption rate of HA/Fe3O4@NH2-MCM-48 reached 243.43 mg/g and 81.23 %, and the adsorption equilibrium is reached quickly within 25 min.