Removal of methylene blue from aqueous solution with self-assembled cylindrical graphene–carbon nanotube hybrid

In this study, we report the efficient removal of organic dye from aqueous solution with a self-assembled cylindrical graphene–carbon nanotube (G–CNT) hybrid which can be directly fabricated by a simple one-step hydrothermal process. The hybrid showed good performance for the removal of methylene blue (MB) from aqueous solution with a maximum adsorption capacity of 81.97 mg g−1. The removal efficiency was found to be 97% at the initial MB concentration of 10 mg L−1. The kinetics of adsorption followed the pseudo-second-order kinetic model, while the Freundlich adsorption isotherm was applicable to describe the equilibrium adsorption process. This study suggests that carbon-based hybrid could be explored as a new adsorbent for removing organic dye pollutants from aqueous solution.

► The self-assembled cylindrical graphene/carbon nanotube hybrid can be fabricated by a simple hydrothermal process.
► The hybrid showed a good adsorption performance for the removal of methylene blue from aqueous solution.
► The adsorption process was characterized by kinetics and isotherm analysis.