Efficient dye-removal via Ni-decorated graphene oxide-carbon nanotube nanocomposites

The nickel nanoparticles decorated graphene oxide-carbon nanotubes nanocomposite has been prepared through a novel molecular-level-mixing method followed by a freeze-drying and subsequent reduction process. The resulting products showed a well-dispersed 3D structure and demonstrated excellent performance in removing Rhodamine B (RhB) from the aqueous solution through a synergistic effect of physical adsorption and photo-degradation. The physical adsorption of RhB by this nanocomposite followed the pseudo-second-order and could be ascribed to its high surface area. The nanocomposite containing 30 wt% of Ni exhibited the highest removal capacity of ca. 41.5 mg g⁻¹ in 5 ppm RhB solution. Meanwhile, because of the ferromagnetism of Ni nanoparticles coated, the nanocomposite could be easily collected and recycled after the removal of dye via magnetic separation. Thus, the nanocomposite have demonstrated great potentials as an efficient adsorbent with good photocatalytic performance for removing organic dyes from wastewater.