MCM-48 modified magnetic mesoporous nanocomposite as an attractive adsorbent for the removal of sulfamethazine from water

A novel magnetic mesoporous nanocomposite FeM48 was synthesized and applied to remove sulfamethazine (SMN) from water. The adsorption kinetics could be expressed by the pseudo-second-order model, where external and interfacial diffusions tended to be the rate-limiting step. The adsorption isotherms at varied temperatures were fitted well with Freundlich model, and thermodynamic analysis revealed that SMN adsorption on FeM48 was a spontaneous exothermic process. Solution pH exhibited a remarkable impact on the adsorption process and the maximum adsorbed concentration was obtained at 6.3. The effect of co-existing anions and humic acid demonstrated that SMN could be adsorbed selectively by FeM48. Hydrogen bonding between the nitrogen of the aniline, sulfinol or pyrimidine group of SMN and the surface hydroxyl group of FeM48 was the major driving force for adsorption. In addition, the pi-pi electron-donor acceptor interaction between SMN (pi-electron acceptor) and MCM-48 (pi-electron donor) also promoted the adsorption process. (C) 2012 Elsevier Ltd. All rights reserved.