B-Scopus

Permanent URI for this communityhttps://dspace.psgrkcw.com/handle/123456789/3730

Browse

Now showing 1 - 2 of 2

POROUS REDUCED GRAPHENE OXIDE (RGO)/WO3 NANOCOMPOSITES FOR THE ENHANCED DETECTION OF NH3 AT ROOM TEMPERATURE
(Royal Society of Chemistry, 2019-02-27) Jeevitha, G; Abhinayaa, R; Mangalaraj, D; Ponpandian, N; Meena, P; Veena, Mounasamy; Sridharan, Madanagurusamy
Incorporation of reduced graphene oxide (rGO) modifies the properties of semiconducting metal oxide nanoparticles and makes it possible to tune the surface area and pore size to optimum values, which in turn improves their gas sensing properties. In this work, to improve the ammonia (NH3) gas sensing characteristics, reduced graphene oxide (rGO) was incorporated into tungsten oxide (WO3) nanospheres using a simple ultrasonication method. The rGO–WO3 nanocomposites exhibited porous nanosheets with nanospherical WO3 as observed with field-emission scanning electron microscopy (FE-SEM). The oxidation state of the rGO–WO3 nanocomposite was determined using X-ray photoelectron spectroscopy (XPS). Three ratios of (1, 5 and 10% rGO/WO3) nanocomposites and pure WO3 showed good selectivity towards NH3 at 10–100 ppm, and more remarkably at room temperature in the range of about 32–35 °C and at a relative humidity (RH) of 55%. The limit of detection (LOD) of the synthesized rGO–WO3 nanocomposites was 1.14 ppm, which will highly favour low detection ranges of NH3. The sensor response was 1.5 times higher than that of the bare WO3 nanospheres. The sensors showed excellent selectivity, ultrafast response/recovery times (18/24 s), reproducibility and stability even after one month of their preparation. We believe that metal oxides using the rGO modifier can improve the sensitivity and reduce the LOD towards NH3 and can be used effectively in real-time environmental monitoring.
TOXIC INFLUENCE OF PRISTINE AND SURFACTANT MODIFIED HALLOYSITE NANOTUBES ON PHYTOPATHOGENIC BACTERIA
(Elsevier, 2019-06-15) Abhinayaa, R; Jeevitha, G; Mangalaraj, D; Ponpandian, N; Meena, P
Halloysite nanotube (Hal nanotube) – a clay mineral nanomaterial, was surface modified using cationic, anionic and non-ionic surfactants – cetyl trimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and Tween 80 respectively. The pristine Hal nanotube and the three surfactant modified Hal nanotubes (SM-Hal nanotubes) were tested against three phytopathogenic bacteria Xanthomonas oryzae, Agrobacterium tumifeciens and Ralstonia solanacearum. In the present study, by performing various bacterial toxicity assays, it has been established that SM-Hal nanotubes had a higher killing efficiency of phytopathogenic bacteria than pristine Hal nanotube. The surfactant modifications improved the dispersion of the Hal nanotube and altered the physico-chemical properties like grain size, particle diameter, surface charge and hydrophilicity, which consecutively enhanced the interaction and the toxic effects on phytopathogenic bacteria. SM-Hal nanotubes inhibited phytopathogenic bacteria at a lower minimum inhibitory concentration (MIC) as compared to the pristine Hal nanotube. Among the three SM-Hal nanotubes, CTAB-modified Hal nanotube effectively suppressed the growth, disrupted the cell membrane integrity, induced higher reactive oxygen species (ROS) production and inhibited the biofilm formation of all the three phytopathogenic bacteria followed by Tween 80-modified and SDS-modified Hal nanotubes. Hence, it is evident that these tailor made SM-Hal nanotubes, can be effectively used as potent clay mineral nanomaterials to control phytopathogenic bacteria.