e) 2021 - 79 Documents
Permanent URI for this communityhttps://dspace.psgrkcw.com/handle/123456789/3923
Browse
Search Results
Item EFFECTS OF ND DOPING ON STRUCTURAL, OPTICAL, MORPHOLOGICAL AND SURFACE-CHEMICAL STATE ANALYSIS OF ZNO NANOPARTICLES FOR ANTIMICROBIAL AND ANTICANCER ACTIVITIES(Elsevier, 2021-04) Indumathi, T; Theivarasu, C; Pradeep, I; Thillai Rani, M; Magesh, G; Sharmila Rahale, C; Ranjith Kumar, EZinc oxide NPs and various concentrations of Nd-ZnO NPs were prepared using a chemical precipitation process. Synthesized nanoparticles have been characterised by X-Ray Diffraction, Fourier Transform Infra-Red Spectroscopy, Scanning Electron Microscope, Transmission Electron Microscopy, Energy Dispersive X-ray Analysis, X-ray Photoelectron Spectroscopy, Micro-Raman and Photo Luminescence (PL) Spectra in order to study structural functional, morphological, elementary and compositional groups. XRD data verified the hexagonal wurtzite structure of the ZnO and Nd-ZnO NPs. Zn-O stretching frequencies ZnO and Nd-ZnO were observed at 423, 466, 423 and 452 cm-1, respectively, from the FTIR spectra. The morphological changes of ZnO and Nd-ZnO NPs have been confirmed by SEM and TEM. The EDAX spectra confirms the chemical composition of the elements involved. XPS confirms the oxidation status of the elements concerned. The peak at 432 cm-1 of the Raman spectra is the E2 phonon mode of the metal oxide NPs involved. The improved photoluminescent properties of Nd-ZnO compared to ZnO NPs are shown by the Photoluminescent (PL) spectra. The antibacterial activity of the synthesised nanoparticles against gram-positive and gram-negative bacteria indicates that the highest concentration of Nd-ZnO (Zn1-xNdxO when x=0.15) shows higher antibacterial activity. The anticancer activity of the synthesised nanoparticles has shown that the low concentration of Nd-ZnO (at Nd concentration is 0.05) is adequate for the 50 percent of cell mortality.Item NATURAL FUELS (HONEY AND COW URINE) ASSISTED COMBUSTION SYNTHESIS OF ZINC OXIDE NANOPARTICLES FOR ANTIMICROBIAL ACTIVITIES(Elsevier, 2021-05-15) Ranjithkumar, B; Ramalingam, H B; Ranjith Kumar, E; Srinivas, Ch; Magesh, G; Sharmila Rahale, C; Nashwa M, El-Metwaly; Chandar Shekar, BA novel green synthesis of the combustion pathway was adopted for the preparation of ZnO nanoparticles using Honey and Cow urine. The effects of honey and cow urine on crystalline size, structure, morphology, band gap and thermal properties of ZnO nanoparticles have been analyzed. The polycrystalline hexagonal wurtzite structure of ZnO nanoparticles is confirmed by XRD spectra. The mean crystalline sizes of the ZnO nanoparticles were 23 nm and 29 nm respectively, for the honey and cow urine phase. The external morphology and grain size of the products have been visualized via FE-SEM and TEM. The average sizes of the grains of the ZnO nanoparticles were perfectly associated with the crystalline size measured from the XRD. Spherical and hexagonal shaped nanostructures were reported using FE-SEM and TEM micrographs. The optical absorption spectra of ZnO nanoparticles have been analyzed using UV–Vis spectrometry. In the FT-IR spectra, around 400 cm−1 to 600 cm−1 range have been allotted to the Zn–O vibration. The thermal properties of ZnO nanoparticles have been analyzed using TGA. Changes in weight loss for different ZnO nanoparticles using honey and cow urine have been documented. Gram Positive (B.Subtilis) and Gram-Negative (E.Coli)Bacteria were tested using plate counting technique to study the antimicrobial activity of ZnO nanoparticles prepared by cow's urine and honey. Compared with cow urine-prepared ZnO nanoparticles, honey-assisted ZnO nanoparticles demonstrate strong antibacterial activity.Item EVALUATION OF GAS SENSOR BEHAVIOUR OF SM3+ DOPED TIO2 NANOPARTICLES(Springer Link, 2021-05-29) Nithya, N; Ranjith Kumar, E; Magesh, G; Arun, A P; Khlood S, Abou-Melha; Gamila, Badr; Nashwa M, El-Metwaly; Gaber A M, Mersal; Sharmila Rahale, CThe Sol–Gel approach is used to synthesize samarium-doped TiO2 nanoparticles (Sm- TiO2 NPs). Research on the structural, morphological and optical properties of TiO2 nanoparticles by XRD, FESEM, TEM, UV, FTIR, and PL was used. The Sm-TiO2 NPs are verified by the XRD profile of anatase, brookite and rutile phase structures. Crystallite size decreases when Sm doped with TiO2 nanoparticles. The external morphologies of the TiO2 nanoparticles in spherically shaped Sm are captured by FESEM. The sample size distribution and polycrystalline composition of the particles have been analyzed using TEM. The EDX spectrum verifies the presence of Ti, O and Sm elements of all the samples. The values have been found to be very close to what has been expected. Sm substitution greatly affected the optical bandgap of TiO2 nanoparticles. It shows that the band gap decreases from 3.64 to 3.61 eV as the concentrations of Sm increases. FTIR confirms the presence of functional groups and Ti–O bonds present in the prepared sample. PL analysis shows the emission for violet range. Using the dip-coating process, a thin film for sensor function is developed. PVDF flat sheet membrane is used as a substrate for sensing material. For various ethanol concentrations with optimized operating temperatures of 303 K, the sensing behaviour of the sensor element is investigated. The very rapid reaction and recovery time of 10 s and 8 s shows that the prepared samples are appropriate for gas sensor applications.Item STUDY OF SOME PHYSICOCHEMICAL PROPERTIES OF MICROWAVE-SINTERED AL3+-DOPED NI-ZN FERRITES FOR GAS SENSOR APPLICATIONS(Springer Link, 2021-05-19) Chandra Sekhar, E; Sreenivasulu, M; Purushotham, Y; Magesh, GA series of Ni0.5Zn0.5AlxFe2–xO4 (0.0 ≤ x ≤ 0.25) nanoferrites have been prepared by sol-gel auto combustion and followed by sintering in a microwave oven at 1100 °C for 30 min. Pure cubic spinel phase was confirmed from the indexed planes in XRD patterns. The experimental lattice parameter (a) was found to be in the range of 8.3908–8.3509 Å in the decreasing order with the doping level of Al3+ ions. The sharp diffraction peaks indicate the crystalline nature of the samples. The microwave sintering is promoting the crystallinity with the substitution of Al3+ ions (42.8–54.4 nm). The saturation magnetization (Ms) gradually decreased with the substitution of Al3+ ions, and highest value of 61.2 emu/g was reported. The dilution of A–B superexchange interaction can be expected from the variation of bond angles. The coercivity is predominantly dependent on the magnetocrystalline anisotropy. Normal dielectric dispersion was observed in the present series of ferrite samples, and the dielectric constant is found to be composition dependent. The low value of dielectric constant was observed for the compositions x = 0.15 and x = 0.25. The present ferrite systems are showing good sensor response to NH3 and least response to H2. In the tested ferrite systems, the composition x = 0.25 is an appropriate selective for sensor fabrication to test NH3 gas.Item EVALUATION OF STRUCTURAL, SURFACE MORPHOLOGICAL AND THERMAL PROPERTIES OF AG-DOPED ZNO NANOPARTICLES FOR ANTIMICROBIAL ACTIVITIES(Elsevier, 2021-09) Ranjithkumar, B; Ranjith Kumar, E; Srinivas, M; Ramalingam, H B; Srinivas, Ch.; Magesh, G; Balamurugan, A; Sharmila Rahale, C; ChandarShekar, BNovel properties of green synthesis methods have paved the way for a new area of study in the scientific community. Systematic research was carried out in the current study for Ag-doped ZnO nanostructures prepared using cow urine and honey. The phase evaluation and surface morphological features of prepared nanoparticles were examined using XRD and FE-SEM analysis. From the XRD analysis, the average crystallite size () was estimated and found to be 25.1 nm for cow urine and 29.9 nm for honey-assisted nanomaterial. FE-SEM confirms the presence of plate-like and spherical nanoparticles in the synthesized sample. Compositional analysis of Zn, Ag, and O from EDX spectra showed the reliability of present green synthesis. The thermal analysis of the nanostructures of Ag-ZnO has been investigated and the effect of these natural ingredients on thermal stability has also been analyzed. Antimicrobial activities were tested against two human pathogenic bacteria and their comparative results are presented.