Synthesis and characterization of ZnO nanorods (original) (raw)
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Water Science & Technology: Water Supply, 2014
ZnO nanorods (ZnO NRs) were grown on ZnO seeded fluorine doped tin oxide (FTO) substrates at low temperatures (90 °C) from Zn2+ precursors in alkaline aqueous solution. The ZnO seeds were deposited on the FTO substrate heated at 350 °C by spray pyrolysis of a zinc acetate solution in a water ethanol mixture. The structure of seeds was tuned by the ethanol water ratio, Γ, which controls the solvent evaporation rate of drops impinging the substrate. The relationship between the microstructure and optical properties of the ZnO NR films and the photocatalytic antibacterial activity for Escherichia coli abatement, was determined through a detailed characterization of the material. The higher photocatalytic antibacterial activity was performed by ZnO NR films grown on seeds deposited from solutions with Γ in the 0.0–0.03 range. With these films, the population of viable E. coli dropped more than six orders, from 8 × 108 to 4 × 102 CFU. These results show the potential of these materials i...
ZnO Nanorods with High Photocatalytic and Antibacterial Activity under Solar Light Irradiation
Materials
ZnO nanorods (NRs) with an average length and diameter of 186 and 20 nm, respectively, were prepared through a mild solvothermal route and used as photocatalysts either as dispersed powder or immobilized on glass slides. The ZnO NRs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Dispersed ZnO NRs and, to a lesser extent, immobilized ZnO NRs were demonstrated to exhibit high photocatalytic activity under simulated sunlight of low intensity (5.5 mW/cm2) both for the degradation of the Orange II dye and for Escherichia coli bacterial decontamination (2.5-fold survival decrease after 180 min irradiation for immobilized NRs). SEM, atomic force microscopy (AFM), fluorescence spectroscopy, and epifluorescence microscopy demonstrate that cell surface damages are responsible of bacterial inactivation. The immobilized ZnO NRs could be reused up to five times for bacterial decontamination at comparable efficiency a...
Journal of Nanoparticle Research, 2011
Nanostructured ZnO photo catalyst was synthesized by precipitation method and was applied in conjunction with 355 nm pulsed laser irradiation for effective disinfection of the water contaminated with Escherichia coli micro organism. The morphological studies using X-Ray Diffractometer (XRD) and Transmission Electron Microscope (TEM) were carried out on the synthesized nano-ZnO, and these studies indicated that the catalyst has the crystallographic structure of hexagonal wurtzite and has the grain size of around 20-40 nm. The bacteria decay rate constants were estimated for nine different concentrations of nano-ZnO in infected water. The parametric optimization was carried out, and we could reach the decay rate constant as high as 0.24 min , -1 which is higher than micro-structured ZnO and the familiar TiO 2 photo catalysts under similar experimental condition.
Synthesis of ZnO Nanorods by Electrochemical Deposition Method and Its Antibacterial Activity
Journal of Nanoengineering and Nanomanufacturing, 2013
ZnO nanorods have been grown on F-SnO 2 substrate by electrochemical deposition method from aqueous solution with different current densities. From, the study of surface morphology, the film grown with low current density was found to be uniform showing the growth of ZnO nanorods along its length. X-ray diffraction study revealed the nanorods deposited at current densities 1.5 m Amp/cm 2 were mainly orientated along 002 directions. From study of UV-vis spectra, band gap was evaluated to be 3.34 eV representing strong excitonic absorption. The violet emission at 423 nm was attributed to the transition of an electron from a deep donor level of neutral zinc interstitial to the valence band. The antibacterial activity of ZnO nanorods was studied for bacteria Escherichia coli, which shows a zone of inhibition around ZnO nanorods indicating a growth inhibition property of ZnO nanorods.
Food Science and Technology International, 2010
Nanoparticles of ZnO and their application in coating systems have attracted a great deal of attention in recent years because of its multifunction property, especially antibacterial activity. In this study, antibacterial and physical properties of poly(vinyl chloride) (PVC) based film coated with ZnO nanoparticles were investigated. It was found that the antibacterial action should be attributed to the killing effect property of ZnO nanoparticles. The ZnO-coated films treated by shaking for 10 h exhibited a similar high antibacterial activity against Escherichia coli and Staphylococcus aureus as the untreated ZnO-coated films. This result indicated that the ZnO nanoparticles adhered very well to the plastic film. The antibacterial activity of the ZnO-coated film to inactivate E. coli or S. aureus was improved by UV irradiation. The analysis of physical properties of the ZnO-coated films revealed that the nano-ZnO particles showed less effects on the tensile strength and elongation at break of the film. The ultraviolet (UV) light fastness of the ZnO-coated PVC film was improved, which may be attributed to the absorption of ZnO nanoparticles against UV light. Water vapor transmission of the ZnO-coated film decreased from 128 to 85 g/m 2 Á 24 h, whereas the thickness of film increased from 6.0 mm with increasing the amount of nano-ZnO particles coated from 0 to 187.5 mg/cm 2 . This research revealed that the PVC film coated with nano-ZnO particles has a good potential to be used as an active coating system for food packaging.
Electroless controllable growth of ZnO films and their morphology-dependent antimicrobial properties
An electroless deposition process was used to synthesize with a controlled morphology, polycrystalline ZnO on glass substrates as antimicrobial coatings. The influence of deposition temperature (Tdep) on the physicochemical and antimicrobial properties of the ZnO films was analyzed. The results indicated that a change in deposition temperature greatly affected the morphology and the degree of crystallinity of the films. Scanning electron microscope images show that the film surface is porous at a deposition temperature of 40 and 50 °C, whereas hexagonal-plate shaped morphology predominated at 60 °C and finally at 70 and 80 °C the films consisted of rod-like particles. The films showed good transparency in the visible region. All ZnO films presented notable antimicrobial activity against the gram-negative bacteria Escherichia coli (E. coli) and the gram-positive Staphylococcus aureus (S. aureus). It was found that the antimicrobial efficiency is strongly dependent on morphology and structural properties. The best antimicrobial performance was recorded for the films consisting of rod-like morphology with a high degree of crystallinity. The procedure used in this investigation is strongly recommended for the development of functional surfaces.
Antibacterial effect of photo-activated zinc oxide nanoparticles capped with different polymers
Journal of Innovations in Pharmaceutical and Biological Sciences, 2018
In this paper, three types of zinc oxide nanoparticles (ZnO NPs) were prepared by a wet chemical method (precipitation method), the first type was ZnO NPs capped with Polyethylene Glycol (ZnONPs@PEG) and other ZnO NPs were capped with Polyvinylpyrroli-done (ZnO NPs@PVP), and the last type of ZnO NPs was provided without polymer. The samples were characterized via X-ray diffraction (XRD). The average crystal size and shape of the prepared ZnO nanopowder were determined by Transmission Electron Microscope (TEM). The antibacterial activity of the three types of ZnO NPs were tested against four types of bacteria that were Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus, All ZnO NPs were photo-activated under the exposure to UV light at 254 nm before being applied against the four types of bacteria. The antibacterial activity of ZnO NPs was determined based on the appearance of zones of inhibition and the standard deviation was calculated for all appeared inhibition zones. The results obtained from TEM imaging revealed the formation of spherical, rods and nano flowers shapes for uncapped ZnO NPs, ZnONPs@PEG and ZnO NPs@PVP respectively. Also, it was found that the Bacillus subtilis inhabited using ZnONPs@PEG more than using the other types of ZnO NP.
Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route
Applied Microbiology and Biotechnology, 2010
The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH 3 COO) 2 ·2H 2 O) and aniline (C 6 H 5 NH 2 ) in 6 h refluxing at ∼65°C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed. The antibacterial activity of ZnO nanoparticles (ZnO-NPs) were studied by spectroscopic method taking different concentrations (5-45 μg/ml) of ZnO-NPs. Our investigation reveals that the lowest concentration of ZnO-NPs solution inhibiting the growth of microbial strain is found to be 5 μg/ml for K. pneumoniae, whereas for E. coli, S. aureus, and S. typhimurium, it was calculated to be 15 μg/ml. The diameter of each ZnO-NPs lies between "20 and 30 nm" as observed from FESEM and transmission electron microscopy images. The composition of synthesized material was analyzed by the Fourier transform infrared spectroscopy, and it shows the band of ZnO at 441 cm −1 . Additionally, on the basis of morphological and chemical observations, the chemical reaction mechanism of ZnO-NPs was also proposed.
ZnO materials with different morphologies have been synthesized via a simple solvothermal method using different solvents without any catalysts, templates or surfactants. The ZnO samples are employed in the inactivation of gram-negative Escherichia coli and gram-positive Staphylococcus aureus in MilliQ water. The photocatalytic activities of samples to degrade an azo dye, Acid Orange 74 (CI 18745), were also tested. XRD data showed that single-phase ZnO with the wurtzite crystal structure but different growth habits were obtained in the different solvents. SEM imaging illustrated that ZnO with flower-like, rod-like, and spherical shape were produced when water, 1-hexanol, and ethylene glycol were used as the solvent, respectively. The optical properties of the as-prepared ZnO materials were investigated by UV-vis absorption and photoluminescence spectra. The antibacterial efficiencies were affected by the physiological status of the bacterial cells, different morphologies and crystal growth habits, particle size and optical properties of ZnO samples. Results indicate that ZnO flower-like showed significantly higher photocatalytic inactivation than ZnO rod-and sphere-like against E. coli compared with S. aureus. It was found that the antibacterial activity of ZnO increased with decreasing crystallite size. The inactivation efficiencies for both organisms under light conditions were higher than under dark conditions. The obtained results were discussed according to the morphologies, optical and structural properties of ZnO powders as key parameters in photocatalytic and antibacterial activity.