Enhancing Adsorption of Multi-Walled Carbon Nanotubes for Dye Removal

beta-Cyclodextrin functionalized magnetic multiwalled carbon nanotubes (MMWNTs-beta CD) were prepared by a facile route, which showed highly adsorptive efficiency for the removal of methylene blue (MB) from aqueous solution. Initially, poly(glycidyl methacrylate) (PGMA) was covalently grafted onto the surface of magnetic nanoparticles by the reversible addition fragmentation chain transfer polymerization of glycidyl methacrylate. The mixture of PGMA grafted magnetic nanoparticles and multiwalled carbon nanotubes (MWNTs) were functionalized with beta-cyclodextrin to afford MMWNTs-beta CD by epoxide ring-opening reaction. The nanocomposites were characterized by FT-IR, SEM, TEM, XRD, and TGA. The MMWNTs-beta CD was found to be superparamagnetic as recorded by SQUID. Decorating magnetic multiwalled carbon nanotubes with beta-cyclodextrin stimulated remarkably the adsorption capacity of plain multiwalled carbon nanotubes in the removal of MB from aqueous solution. The MMWNTs-beta CD could be recycled and remained the adsorption capacity of 61.8% after five cycles of adsorption desorption.