Synthesis of magnetic ZnO/ZnFe2O4 by a microwave combustion method, and its high rate of adsorption of methylene blue.

The magnetic ZnO/ZnFe2O4 particles have been synthesized by a microwave combustion method using NaAc as fuel. The as-obtained ZnO/ZnFe2O4 was characterized and applied for the removal of methylene blue (MB) from aqueous solution in the batch system. The ZnO/ZnFe2O4 particles display larger S(BET) and smaller size with increase of NaAc dosage. Because a certain amount of gas is generated during NaAc decomposing and the gas prevent the particles from growing larger. More interestingly, even at neutral pH value, the ZnO/ZnFe2O4 obtained with 24 mL NaAc shows high-rate adsorption properties with the MB removal efficiency up to 90% in 0.5 min and a maximum adsorption capacity of 37.27 mg/g.