G. Hota

Iron oxide nanoparticle-immobilized PAN nanofibers: synthesis and adsorption studies

In this study we have prepared (polyacrylonitrile) PAN/iron oxide composite nanofibers by three different methods and have compared their removal efficiency for the adsorption of Congo Red (CR) dye from aqueous solution. In the first method, we have prepared electrospun PAN/iron(III) acetylacetonate composite nanofibers by electrospinning followed by a hydrothermal method for in situ growth of iron oxide nanoparticles on the surface of PAN nanofibers. In the second method the electrospun PAN nanofibers were immersed into the iron alkoxide solution followed by a hydrolysis reaction at 80 °C. In the third method, PAN/iron oxide composite nanofibers were prepared by blending the previously prepared iron oxide nanoparticles with the PAN solution followed by an electrospinning technique. The obtained different nanocomposite fibers were characterized by attenuated total reflectance-Fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FE-SEM) analytical techniques. The FE-SEM images clearly show the formation of iron oxide nanoparticles that are uniformly decorated on the surface of PAN nanofibers after hydrothermal reactions. The average diameters of the nanoparticles are observed to be in the range of 30 to 120 nm. The adsorption experiments such as effect of pH, contact time, initial concentration variation, and temperature were explored in the batch experiments. CR dye is used as a model organic pollutant for an adsorption study. An adsorption isotherm, kinetic study and thermodynamic study were also carried out to elucidate the adsorption mechanism.

Hydrothermal synthesis and enhanced photocatalytic activity of ternary Fe2O3/ZnFe2O4/ZnO nanocomposite through cascade electron transfer

This work represents the synthesis and photocatalytic activity of α-Fe2O3 nanoparticles and mixed oxide nanocomposites such as Fe2O3/ZnFe2O4, Fe2O3/ZnFe2O4/ZnO and ZnFe2O4/ZnO. The above mentioned nanomaterials were synthesized by hydrothermal method by varying the molar ratio of iron and zinc salts followed by calcination at 500 °C. The crystalline phase, surface morphology and size of the prepared nanomaterials were characterized by XRD, FESEM & TEM analysis. FESEM and TEM images indicate the formation of irregular shape for α-Fe2O3 and cubical shape for nanocomposite systems having diameter in the range of 80–100 nm. The prepared nanomaterials were used for photocatalytic degradation of malachite green in aqueous media under solar light irradiation. The nanocomposites exhibit enhanced photocatalytic activity as compared to α-Fe2O3 nanoparticles. However, Fe2O3/ZnFe2O4/ZnO (Fe : Zn = 70 : 30) nanocomposite exhibits highest photocatalytic activity. This result might be due cascade electron transfer mechanism in the ternary phase.