Synthesis and characterization of magnetic β-cyclodextrin-chitosan nanoparticles as nano-adsorbents for removal of methyl blue

A novel nano-adsorbent, beta-cyclodextrin-chitosan (CDC) modified Fe3O4 nanoparticles (CDCM) is fabricated for removal of methyl blue (MB) from aqueous solution by grafting CDC onto the magnetite surface. The characteristics results of FUR, SEM and XRD show that CDC is grafted onto Fe3O4 nanoparticles. The grafted CDC on the Fe3O4 nanoparticles contributes to an enhancement of the adsorption capacity because of the strong abilities of CDCM, which includes the multiple hydroxyl, carboxyl groups, amino groups and the formation of an inclusion complex due to the beta-CD molecules through host-guest interactions, to adsorb MB. The adsorption of MB onto CDCM is found to be dependent on pH and temperature. Adsorption equilibrium is achieved in 50 min and the adsorption kinetics of MB is found to follow a pseudo-secondorder kinetic model. Equilibrium data for MB adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for MB is estimated to be 2.78 g/g at 30 degrees C. The CDCM was stable and easily recovered. Moreover the adsorption capacity was about 90% of the initial saturation adsorption capacity after being used four times. (C) 2011 Elsevier B.V. All rights reserved.