Adsorption Characteristic of Methyl Blue onto Magnetic CaFe2O4 Nanoparticles Prepared via the Ethanol-Assisted Combustion Process

CaFe2O4 nanoparticles were prepared successfully and characterized by SEM, TEM, XRD and VSM. The effects of ethanol dosage, calcination temperature, heating rate and calcination time on CaFe2O4 nanoparticles were investigated via the ethanol-assisted combustion process. To obtain the maximum adsorption capacity, CaFe2O4 nanoparticles calcined at 400 ? in 40 mL anhydrous ethanol with the heating rate at 3 ?/min for 2 h were selected to adsorb methyl blue (MB). The adsorption process of MB onto CaFe2O4 nanoparticles conformed to the pseudo-second-order kinetics model and the Temkin isotherm model, indicating that the process was a mixture of monolayer and multilayer chemisorption. When pH was 3, the adsorption capacity of MB onto CaFe2O4 nanoparticles was the largest, and after 6 cycles, the adsorption efficiency of CaFe2O4 nanoparticles could still reach 65% of the first time, indicating good regeneration performance.