GREEN SYNTHESIS, CHARACTERIZATION, MODIFICATIONS AND APPLICATIONS OF ZINC OXIDE NANORODS
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Date
2018
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UNIVERSITY OF ILORIN
Abstract
The demand for clean energy and clean water is becoming challenging issues having been greatly influenced by human’s lifestyle and the growing world population. Nanotechnology offers promising solution through the applications of nanomaterials. The orthodox methods of synthesizing nanomaterials are expensive and generate hazardous toxic chemicals. Green method route of synthesis has become an alternative to overcome such limitations. This research work therefore aimed at synthesising a multifunctional zinc oxide nanorod through green principle route of synthesis. The objectives were to: (i) synthesize Mangifra indicaleave extract-mediated zinc oxide nanorods (ZnO NR); (ii) synthesize spinel nickel ferrite nanorods (NF NR); (iii) modify the ZnO NR with NF NR by calcination to obtain a nickel ferrite-zinc oxide nanocomposite; (iv) characterize the synthesized nanostructures for structural, elemental composition, functional groups,morphological and optical studies using X – Ray Diffractometer XRD, Fourier Transform Infrared (FTIR), Energy Dispersive X-ray Spectrometer (EDX), Scanning Electron Microscope (SEM), UV-VIS Spectrophotometer, and Photoluminescence (PL) spectroscopy respectively; (v) examine the applications of the synthesized nanostructures for dielectric studies, solar cell nanocoating, biosensing, photodegradation and treatment of both domestic and industry waste water.
Green principle route of synthesis was used for the synthesis of zinc oxide nanorods. The zinc oxide nanorods (ZnO NR) were modified with spinel nickel ferrite nanorods (NF NR) by calcination both at 850 0C for ten hours to obtain zinc oxide-nickel ferrite (ZnO/NF) nanocomposite. Both unmodified and modified ZnO NR were characterized and examined for applications in dielectrics, solar cell nanocoating, glucose sensing, photodegradation and waste water treatment.
The findings of this research work showed that:
(i) ZnO NR have been synthesized by green synthesis route and had been successfully modified with nickel ferrite nanorods synthesized by coprecipitation method.
(ii) the dielectric constantε/ of the green synthesized ZnO NR is very high (750) with capacitance value of 0.78 pF. Its dielectric loss Ԑ//, dielectric loss angle, σdecreases with increasing frequency and then reaches a constant value, hence a good dielectric.
(iii) the fill factor of a silver solar cell coated with the green synthesized ZnO NR by drop-casting method was enhanced showing improved solar cell efficiency up to 5%.
(iv) the modified ZnO NR was successfully used as a biosensor for glucose.
(v) the photocatalytic studies reveal that the ZnO/NF nanocomposite exhibits high degradation efficiency under UV light and that •OH and photoproduced holes h+ are the main species in the removal of the organic dyes solution.
(vi) for the treatment of domestic and industrial waste water, the green synthesized ZnO NR showed 93.95% and 93.95% of chemical oxygen demand (COD) reduction in 75 minutes.
This research work concluded that green synthesis route is suitable for the synthesis of ZnO NR, appropriate modification of which makes it multifunctional. It is recommended that, green synthesis method should be adopted for the synthesis of ecofriendly, cost effective and multifunctional ZnO NR.
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GREEN SYNTHESIS, CHARACTERIZATION, MODIFICATIONS, APPLICATIONS, ZINC OXIDE NANORODS