Chitosan/organic rectorite composite for the magnetic uptake of methylene blue and methyl orange.

In this study, magnetic particles were prepared using organic rectorite as a carrier, and then a novel magnetic adsorbent named chitosan/organic rectorite-Fe3O4 intercalated composite microspheres (CS/Mt-OREC microspheres) was synthesized. The microspheres were characterized by XRD, FT-IR, TEM, SEM and VSM. The effects of adsorbent dosage, initial pH, contact time, temperatures, initial concentrations of methylene blue (MB) and methyl orange (MO) were studied. The adsorption process followed the pseudo-second-order kinetics, and the intra-particle diffusion was one but not the only rate-limiting step. The adsorption equilibrium data can be well described by Langmuir model. Thermodynamic parameters such as ΔG, ΔH, and ΔS were estimated to understand the adsorption mechanism of dyes. Moreover, CS/Mt-OREC microspheres were successfully regenerated using NaOH and HCl, and could be easily separated from aqueous solution in magnetic field.