Arunkumar Lagashetty

Microwave-assisted route for synthesis of nanosized metal oxides

Abstract Microwave-assisted route for the synthesis of nanomaterials has gained importance in the field of synthetic technology because of its faster, cleaner and cost effectiveness than the other conventional and wet chemical methods for the preparation of metal oxide nanoparticles. In the present work, synthesis of metal oxide nanoparticles viz., γ-Fe2O3, NiO, ZnO, CuO and Co-γ-Fe2O3 were carried out by microwave-assisted route through the thermal decomposition of their respective metal oxalate precursors employing polyvinyl alcohol as a fuel. The metal oxide nanoparticles are then characterized for their size and γ to α (in γ-Fe2O3) transition and structure by employing powder X-ray diffraction (XRD) pattern, high-temperature X-ray diffraction (HTXRD) pattern and Fourier transform infrared (FT-IR) spectral studies. The morphology of the samples ranged from nanorods to irregular-shaped particles for different metal oxide samples on the basis of scanning electron microscopy and transmission electron microscopy images. Frequency-dependent dielectric study of the ferrite samples (γ-Fe2O3 and Co-Fe2O3) showed a similar behaviour, where the dielectric constant decreased rapidly with increase in frequency. Possible explanation for this behaviour is given.

Synthesis of MoO3 and its polyvinyl alcohol nanostructured film

The synthesis of ultrafine MoO3 through a self-propagating combustion route employing polyethylene glycol as fuel is reported. The precursor molybdenum oxalate is employed in this study for the conversion of the precursor to ultrafine MoO3 particles. The solvent casting method is adopted for the synthesis of MoO3 dispersed polyvinyl alcohol nanostructured film (MoO3-PVA). These synthesized MoO3 and their composite samples are characterized for their structure, morphology, bonding and thermal behaviour by XRD, SEM, IR and DSC techniques, respectively. The distribution of MoO3 in polyvinyl alcohol gives a crystalline polymer, a compact structure and an increase in glass transition temperature.

Combustion Derived Ultrafine γ-Fe2O3 Structure, morphology and thermal studies

A novel combustion method of employing poly(ethylene glycol) with the precursor in a fixed ratio for the synthesis of ultrafine γ-Fe2O3 through a self-propagating combustion synthesis is reported. Four different precursors viz. ferrous hydroxide, ferrous oxalate dihydrate, ferric 8-hydroxyquinoline and ferric acetylacetonate are employed in this study for the conversion of these precursors to ultrafine g-Fe2O3 particles. The as synthesized γ-Fe2O3 samples are characterized by XRD, SEM and thermal techniques. A case study for the synthesis of γ-Fe2O3 employing ferric acetyl acetonate as precursor is reported. The importance of employing thermal analysis techniques in understanding the combustion synthesis is envisaged.

Adsorption study of Pb2+ ions on nanosized SnO2, synthesized by self-propagating combustion reaction

Novel combustion synthetic route for the synthesis of nanosized SnO2 is reported. X-ray, tap and powder densities of SnO2 are calculated. Adsorption of Pb2+ ions on combustion derived nanosized SnO2 is studied. The as synthesized SnO2 and lead ions adsorbed SnO2 are characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), and infrared spectroscopic (IR) techniques. The eluent is characterized by atomic absorption spectroscopy (AAS) and solution conductivity (SC) to know the reduction in the concentration and increase in conductance of lead solution after adsorption on the SnO2 surface. The potential use of solid adsorbents for the adsorption of heavy metal pollutants is envisaged in the present work.