Green synthesis of amino-functionalized carbon nanotube-graphene hybrid aerogels for high performance heavy metal ions removal

摘要

In this study, the ultra-lightweight and robust three-dimensional graphene/polydopamine modified multiwalled carbon nanotube (MWCNT-PDA) hybrid aerogels were prepared via a viable green route and applied to highly efficient heavy metal ions adsorption. No additional reducing agents were required during the molding of the hybrid aerogel, thus greatly reducing the environment pollution emissions. The MWCNT-PDA in right amounts provided the hybrid aerogels with satisfying structure stability and effectively prevented the stacking of GO sheets, as well as exposed more active sites to improve the adsorption of heavy metal ions. Benefiting from the large specific surface area, porous structure and competent active sites, the resulting hybrid aerogels showed superior adsorption performance for heavy metal ions, and the saturated adsorption capacities were as large as 318.47 and 350.87 mg g(-1) for Cu(II) and Pb(II), respectively, calculated by the Langmuir isotherm model. The research revealed that the synergistic effects of the surface complexation and chelation between active sites in hybrid aerogels and heavy metal ions were the dominant adsorption mechanisms. High adsorption capacity and easy separation from water after adsorption make the hybrid aerogels an ideal choice for heavy metal ions treatment in practical application.