Synthesis and adsorption behavior of magnetic microspheres based on chitosan/organic rectorite for low-concentration heavy metal removal

Abstract This study provided a new idea for the preparation of magnetic nanoparticles using organic rectorite as a carrier, and a novel magnetic adsorbent, chitosan/organic rectorite-Fe3O4 composite microspheres (CS/χOREC-Fe3O4), was synthesized. The structure and physical properties of CS/χOREC-Fe3O4 were characterized by XRD, SEM, TEM, FT-IR, TG, Ms and XPS and its adsorption properties for removal of 3 mg/L heavy metal ions under different conditions were also investigated. The results showed that the CS/χOREC-Fe3O4 microspheres exhibited excellent adsorption capacity for removing metal ions compared with the corresponding OREC-Fe3O4 or chitosan alone. The adsorption process was fitted to Langmuir model and pseudo-second-order kinetic model. The Ea and ΔG revealed that the adsorption of Cu (II) and Cd (II) proceeded with a low potential energy and all the adsorption processes were spontaneous. Further recycle experiments exhibited the adsorption capacity of adsorbent still maintained above 55% after the 4th cycle. All results implied that CS/χOREC-Fe3O4 could be used as a promising adsorbent.