Facile preparation of chitosan enwrapping Fe3O4 nanoparticles and MIL-101(Cr) magnetic composites for enhanced methyl orange adsorption

A novel magnetic composite bioadsorbents composed of chitosan wrapping various content of nanoscale Fe3O4 and MIL-101 ([Cr3F(H2O)(2)O(bdc)(3)], bdc = 1,4 benzenedicarboxylate, m-CS/Fe3O4/MIL-101) were prepared for the adsorptive removal of a harmful anionicdye methyl orange (MO), from aqueous solutions. The introduction of chitosan could obviously increase the adsorption capacity of MO onto the metal-organic frameworks by about 40 % in comparison with pure MIL-101. The adsorption kinetics was investigated, and the experimental data and adsorption isotherms were better fitted by pseudo-second order kinetic model and Langmuir isotherm, respectively. Furthermore, the m-CS/Fe3O4/MIL-101 composites are reusable after adsorption in water and could be effectively separated by applying a magnetic field after adsorption.