Surface modification of carbon nanotubes with polyethyleneimine through “mussel inspired chemistry” and “Mannich reaction” for adsorptive removal of copper ions from aqueous solution

Abstract

A number of nanomaterials, such as silicon dioxide, graphene oxide, nano-diamond, etc. have been discovered and reported for various applications in recent years. The removal of environmental pollutants using nanomaterials should be one of the most important topics owing to their small size, high specific surface areas and catalytical properties. However, the removal capability of some nanomaterials is still need to improve for the lack of active adsorption sites. The surface modification of nanomaterials to endow new functional groups should be promising route to improve their adsorption performance. In this work, a novel strategy that combination of mussel inspired chemistry and Mannich reaction was reported for the first time for preparation of CNT@PDA@PEI composites. The adsorption behaviors of the modified carbon nanotubes (CNT) and pristine CNT toward Cu2+ have been determined and compared to verify the effects of surface modification. The CNT related samples were characterized by a series of instruments. The results further indicated that the method is an excellent route of surface modification of CNT. The adsorption experimental results suggested that the functionalized CNT via the combination of Mannich reaction and mussel inspired chemistry was an excellent adsorbent for removal of Cu2+. To the best of our knowledge, this is the first report for surface modification of CNT through the combination of mussel inspired chemistry and Mannich reaction. This method could also be expanded for the surface modification of other materials for various applications owing to the universality of mussel inspired chemistry and well designability of multicomponent reactions.