Facile preparation of carbon nanotubes based carboxymethyl chitosan nanocomposites through combination of mussel inspired chemistry and Michael addition reaction: Characterization and improved Cu2+ removal capability

The adsorption removal of heavy metal ions from aqueous solution using polymer nanocomposites has attracted great interest because of their advantages from both nanomaterials and polymers. In this work, a facile and novel method has been developed for surface modification of multiwalled carbon nanotubes (CNT) with carboxymethyl chitosan via combination of mussel inspired chemistry and Michael addition reaction. To obtain resultant CNT based chitosan nanocomposites (CNT-PDA-CS), pristine CNT were first coated with polydopamine (PDA) thin films through self polymerization of dopamine under alkaline aqueous solution. Then PDA modified CNT were further functionalized with carboxymethyl chitosan (CS) via Michael addition reaction. The successful preparation of CNT-PDA-CS nanocomposites was ascertained by a series of characterization techniques including transmission electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis and X-ray photoelectron spectrometry. The utilization of the resultant CNT-PDA-CS for removal of Cu 2+ from aqueous solution was also examined in this work. The results showed that CNT-PDA-CS exhibited obviously enhanced Cu 2+ removal capability as compared with the unmodified CNT. Considered the versatility of mussel inspired chemistry, the method described in this work should be a general route for fabricating highly efficient adsorbents, which should be of great interest for environmental applications.