Synthesis of biogenic SnO2 nanoparticles and evaluation of thermal, rheological, antibacterial and antioxidant activities

Quantum confined SnO2 nanoparticles with tunable band gap are synthesized at room temperature using biogenic method. The crystalline and morphological changes during heat treatment of the synthesized samples are discussed using XRD and TEM analysis. Better visible emission intensity is observed at an excitation wavelength of 265 nm for the nanoparticles. Nanofluids with concentrations of SnO2 nanopartides up to 25 weight percentage are used for the thermal conductivity and rheological studies. A thermal conductivity enhancement of 24% is observed within the selected range whereas the viscosity is found to be independent of shear rate for all chosen concentration of SnO2/ethylene glycol nanofluids. The in vitro antioxidant study of samples treated at two different temperatures using DPPH assay provide the possibility of improving radical scavenging activity by varying the preparation conditions. The increased presence of SnO2 nanoparticles enhances the antibacterial activity of the nanoparticles. (C) 2014 Elsevier B.V. All rights reserved.