Removal and surface photocatalytic degradation of methylene blue on carbon nanostructures

Removal and photodegradation of methylene blue on the surface of three distinct carbonaceous materials, pure and nitrogen-doped multi-walled carbon nanotubes, and graphitic nanoribbons, were examined. Carbon nanostructures were characterized by scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, and N-2 adsorption/desorption isotherms. Removal and photocatalytic activity were evaluated by static adsorption under UV irradiation. Photocatalytic activity on carbon nanostructure exhibited a pseudo-first-order kinetic model. The adsorption capacity and photocatalytic activity of carbon nanostructures were mainly attributed to their defective and reactive surface. Nitrogen-doped multi-walled carbon nanotubes showed the best adsorption capacity and photocatalytic activity, which can be attributed to the highly reactive sites due to nitrogen doping, also by pi-pi electron donor-acceptor interaction between sp(2) lattice of carbon nanostructure surface and negatively charged sites at methylene blue molecules.

Automated summary

The removal and photodegradation of methylene blue on the surface of different carbonaceous materials, including pure and nitrogen-doped multi-walled carbon nanotubes, and graphitic nanoribbons, were examined. Nitrogen-doped multi-walled carbon nanotubes showed the best adsorption capacity and photocatalytic activity, attributed to their highly reactive sites due to nitrogen doping and pi-pi electron donor-acceptor interaction with methylene blue molecules on the surface of carbon nanostructures.