A facile low-cost scheme for highly photoactive Fe3O4-MWCNTs nanocomposite material for degradation of methylene blue

Abstract

MWCNTs with Fe3O4 nanoparticles (NPs) were successfully synthesized via a one-step co-precipitation method. The different characterization confirmed the formation of nanocomposite where the surfaces of MWCNTs were decorated with Fe3O4 NPs. The improved optical properties with a 1.6 eV bandgap were achieved for the nanocomposite which is far lower than the pure Fe3O4 NPs (2.7 eV) reported in the literature. The average particle size of Fe3O4 NPs was found to be 12 nm. The photodegradation of MB were carried out using Fe3O4 MWCNTs NC as a photo catalyst. The MB was found to be effectively degraded in a pH range of 10–12. The maximum removal efficiency was achieved as 98.49 % in just 60 min with 40 mg of photocatalyst and 100 ml MB solution at pH 11, while the temperature was maintained at 50 °C. The rate constant k and the R2 values for second order kinetics were found to be 0.7398 ppm/min and 0.9484, respectively. The charge transport kinetics and the mechanism of MB photodegradation process were also studied. The suppressed photogenerated electron-hole pair recombination, reduced interfacial charge transport resistance and high charge separation efficiency were responsible for the highly efficient photocatalytic degradation of MB.

Keywords

• Fe3O4-MWCNTs nanocomposite
• Photocatalytic degradation
• Multiwalled carbon nanotubes
• Methylene blue