Removal of alizarin red from water environment using magnetic chitosan with Alizarin Red as imprinted molecules

A novel, chitosan coating on the surface of magnetite (Fe3O4) (MIMC) was successfully synthesized using alizarin red (AR) as a template for adsorption and removal of AR from aqueous solutions. Characterization of the obtained MIMC was achieved by FTIR spectra, SEM micrographs and XRD. Batch adsorption experiments were performed to investigate the adsorption conditions, selectivity and reusability. The results showed that the maximum adsorption capacity was 40.12 mg/g, observed at pH 3 and temperature 30 degrees C. Equilibrium adsorption was achieved within 50 min. The kinetic data, obtained at the optimum pH 3, could be fitted with a pseudo-second-order equation. Adsorption process could be well described by Langmuir adsorption isotherms and the maximum adsorption capacity was calculated as 43.08 mg/g. The selectivity coefficient of AR and other dyes onto MIMC indicated an overall preference for AR, which was much higher than non-imprinted magnetic chitosan beads. Moreover, the sorbent represented high stability and good repeatability. (C) 2011 Elsevier B.V. All rights reserved.