Abstract
The adsorption of Acid Red 151 (AR151) from water was determined for kaolin, MnFe2O4 and MnFe2O4/kaolin magnetic nano-composite. MnFe2O4 and MnFe2O4/kaolin were prepared using a simple chemical co-precipitation procedure. The MnFe2O4/kaolin composite was prepared with Mn : Fe : kaolin mass ratios of 1 : 1 : 10, 1 : 1.5 : 10 and 1 : 2 : 10. The adsorption capacity increased in 1 : 2 : 10 Mn : Fe : kaolin. Powder XRD and SEM were used to characterize the sorbents. The spinel magnetic phase is present in the MnFe2O4. The AR151 adsorption is strongly dependent on pH and increases with increasing acidity with a maximum at pH 2. The adsorption capacity of the composite is greater than that of natural kaolin and MnFe2O4. The adsorption was not affected by the presence of chloride, but was significantly affected by sulfate. The adsorption kinetics of AR151 on kaolin and ferrite powder are similar, but the adsorption of AR151 on the MnFe2O4/kaolin composite is much more rapid and occurs within 2–5 min of contact. The adsorption process follows pseudo-second order kinetics. The solid magnetic composite could be conveniently recovered after adsorption.