A dual function magnetic nanomaterial modified with lysine for removal of organic dyes from water solution

Novel Fe3O4 magnetic nanoparticles (MNPs) modified with low toxic 3-glycidoxypropyltrimethoxysilane (GPTMS) and lysine (Lys) were synthesized. The MNPs were characterized by transmission electron microscopy, X-ray diffraction, infra-red spectra and thermogravimetric analysis. The MNPs were used to remove anionic dyes and cationic dyes, including methyl blue (MB), orange I (OR), acid red 18 (AR) and methylene blue (MEB), azure I (AZ), from aqueous solution. We investigated organic dye uptake capacity of Fe3O4@GPTMS@Lys as a function of contact time, dye concentration, and different pH. Furthermore, adsorption isotherms and kinetics were studied to understand the mechanism by which the MNPs adsorb dyes. To our delight, the improved adsorbent can not only enhance the maximum adsorption capacity for anionic dyes but also efficiently remove cationic dyes (AZ and MEB) from aqueous solution. (C) 2013 Elsevier B.V. All rights reserved.