Synthesis, structural, optical and magnetic properties of NiFe2O4/MWCNTs/ZnO hybrid nanocomposite for solar radiation driven photocatalytic degradation and magnetic separation

Novel multifunctional NiFe2O4/MWCNTs/ZnO hybrid nanocomposite has been successfully synthesized via the hydrothermal and the co-precipitation methods at 210 degrees C and 90 degrees C, respectively, to be used as a solar radiation driven photocatalytic material. The hybrid nanocomposite exhibits enhanced photocatalytic activity compared to NiFe2O4 and ZnO for decolorization of Methylene Blue (MB) dye -as a model pollutant - from aqueous solutions under solar radiation. Different complementary analytical tools were used to investigate the structural, optical and magnetic properties of the photocatalyst which possess good light response ability, photocatalytic stability, magnetic separation performance and reproducibility. The results from optical degradation confirmed the synergistic effect between the NiFe2O4, the ZnO and the MWCNTs. Suppressed recombination of electron-hole pairs mean more efficient charge separation and enhanced photocatalytic activity. The apparent rate constant (k(app)) of the MB decolorization for a duration of 300 min using NiFe2O4/MWCNTs/ZnO, NiFe2O4 and ZnO photocatalysts were found to be 0.00438 min(-1), 4.12857E(-4) min(-1) and 0.002 min(-1) respectively. The removal efficiency was also investigated for different pH values. Due to the magnetic properties of the nanocomposite, it was possible to separate it after degradation experiments and hence re-usability is possible. In view of the enhanced solar radiation driven photodegradation, the present composite can present a robust alternative as a solar radiation driven photocatalyst.