Particle Size Of ZnO Nanoparticles Research Articles

Eco-Friendly Synthesis of Ag-ZnO Nanocomposite Using Aloe-vera, Hibiscus Sabdariffa Plants and Their Antibacterial and Anti-fungi Activities

The current study used extracts from the aloe vera (AV) plant and the hibiscus sabdariffa flower to make Ag-ZnO nanoparticles (NPs) and Ag-ZnO nanocomposites (NCs). Ag/ZnO NCs were compared to Ag NPs and ZnO NPs. They exhibited unique properties against bacteria and fungi that aren't present in either of the individual parts. The Ag-ZnO NCs from AV showed the best performance against E. coli, with an inhibition zone of up to 27 mm, compared to the other samples. The maximum absorbance peaks were observed at 431 nm and 410 nm for Ag NPs, at 374 nm and 377 nm for ZnO NPs and at 384 nm and 391 nm for Ag-ZnO NCs using AV leaf extract and hibiscus sabdariffa flower extract, respectively. Using field emission-scanning electron microscopes (FE-SEM), the green synthesis of the shown NPs and NCs was found. The Ag NPs particle sizes ranged from 16.99 to 26.39 nm for AV and from 13.11 to 29.50 nm for hibiscus sabdariffa flowers, respectively. The particle size of ZnO NPs ranged from 23.04 to 32.58 nm and from 37.99 to 79.59 nm via AV and hibiscus sabdariffa flowers, respectively. Finally, the particle size of the Ag/ZnO nanocomposite ranged from 22.39–40.05 nm and from 59.73–87.05 nm via the AV and hibiscus sabdariffa flowers, respectively.

Eco-friendly Green Synthesis of stable ZnO nanoparticles using citrus limon: X-Ray Diffraction Analysis and Optical Properties

Eco-friendly stable ZnO nanoparticles (NPs) were synthesized by sol-gel method using citrus limon as a chelating agent. The structural analysis and optical properties of ZnO NPs annealed in air ambient at different temperatures ranging from 600 to 900 °C are reported. A detailed x-ray diffraction (XRD) analysis of ZnO NPs has been discussed. Morphological and optical properties of the NPs were investigated using Field Emission Scanning Electron Microscopy (FE-SEM), XRD, Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy techniques. The FE-SEM reveals that the average particle size of ZnO NPs increased from 62 to 77 nm due to agglomeration of particles or Ostwald ripening which usually happens at high temperature. Physical and microstructural properties such as crystallite size, strain, stress and dislocation density of ZnO NPs were obtained from XRD spectra studies and compared the estimated parameters by various models. It is observed that, the crystallite size increased after annealing and the strain present in NPs is due to defects. Kubelka-Munk function is used to obtain bandgap of NPs from DRS spectra. A slight decrease in the bandgap of ZnO NPs is due to the increase in particle size. PL spectra reveals that the emission around 402 nm near the UV region is attributed to the near band edge emission (NBE) and emission peaks in a visible region is due to the transition of electrons from traps in bandgap to the valence band.

Study of induced amplification of antibacterial activity of ciprofloxacin on coupling with ZnO nanoparticles (ZnONp)

The gradual rise in the resistivity of bacterial strains towards the broad-spectrum antibiotics is alarming and pretence an urgent threat to mankind in the near future. Advanced strategies are a necessity to combat this issue in order to reduce the mortality as well as infection rates. One of the possible routes to address the antibiotic resistivity of bacterial strains is to amplify the effect of antibiotics. Zinc oxide nanoparticles (ZnONp) are able-bodied antimicrobial agents that are regarded as non-hazardous and bio-friendly. Herein we describe in our study the successful synthesis and characterization of ZnONp, followed by the induced amplification of the antibacterial activity of Ciprofloxacin by coupling with Synthesized ZnONp. The synthesized Zinc Oxide Nanoparticles (ZnONp) were characterized using XRD and FE-SEM studies. The particle size of ZnONp was found to be 25–70 nm. The present study aims to investigate the antibacterial effect of synthesised ZnONp against the bacterial strains of S. aureus, E. coli, Pseudomonas and S. mutans as well as the study aims to analyse the amplification of the antibacterial activity of Ciprofloxacin on coupling with Synthesized ZnONp. The Disc diffusion technique was used to determine the antibacterial activity of ZnONp, Ciprofloxacin and ZnONp-Ciprofloxacin couple against the bacterial strains. The results indicated that the ZnO nano particles potentiate bactericidal efficacy of ciprofloxacin antibiotics.

Synthesis of ZnO nanoparticles by Ball-milling process for biological applications

This research is focus on synthesis of ZnO nanoparticles (ZnO-NPs) for biological application by Ball-milling process. This research presents the synthesis of ZnO nanoparticles with the difference calcined temperatures ranging from 400 to 900 °C effect on size and morphology. The synthesis ZnO nanoparticles were characterized by employing technique including X-ray diffraction technique (XRD), Fourier Transform Infrared spectroscopy (FT-IR) and Raman spectroscopy. The morphology and size of ZnO nanoparticles determined by Field Emission Scanning Electron Microscope (FE-SEM) and finally studied the effect of antibacterial activity of ZnO NPs. It was found that the temperature at which high purity ZnO is ≥ 800 °C. Especially, at 800 °C, the smallest particle size of ZnO nanoparticles was obtained. The morphology of ZnO nanoparticles from Ball-milling process is spherical. Bacteriological properties of ZnO nanoparticles were found that the synthesis by using the Ball-milling process was high effective to inhibit bacteria.

Evaluation of anti-bacterial and rice seed germination potential of green and chemically synthesized ZnO nanoparticles

The present study focus on evaluation of the seed germination as a agricultural important, by green synthesizes and (poly vinyl alcohol coated ZnO nanoparticles) chemical synthesis using co-precipitation method using urea as a reducing agent, its characterization has been done by various instrumental techniques. Synthesized ZnO nanoparticles were characterized by UV–Vis spectroscopy depicted the absorption peak around 350 nm which indicates that ZnO nanoparticles displays excitant absorption due to their large excitant binding energy at room temperature. The main functional groups responsible for reduction reaction which were presented in the sample were identified by Fourier Transform infrared spectroscopy, the crystalline structure and d-spacing of ZnO nanoparticles has been confirmed with “X-ray diffraction studies”. The average crystalline size of particles found to be 51 nm using Debye Scherer formulae. Scanning electron microscopy and atomic force microscopy were used for evaluate the morphology and particle size of ZnO nanoparticles and found that the particle size of nanoparticles are between 2 nm to 10 nm. The elemental signals of Energy dispersive spectroscopy analysis was confirmed the presence of Zn, O elements. Seed germination properties of synthesized ZnO nanoparticles have been successfully tested with different concentration as it is agriculturally essential element for development of high crop yields.

Green synthesis of ZnO nanoparticle using Prunus dulcis (Almond Gum) for antimicrobial and supercapacitor applications

ZnO nanoparticles (NPs) using Prunus dulcis (Almond gum) was synthesized by greener approach. The hexagonal phase with wurtzite structure was confirmed by X-ray diffraction study. The size of the ZnO NPs were calculated and it was found to be ∼30 nm. From the FTIR analysis confirms the presence of Zn band and other vibrations modes that are represent in the sample. However, from the absorption spectrum, it was noted that upto 243 nm absorption edges and the cutoff wavelength of 243.93 nm was calculated from ZnO NPs. From the cutoff wavelength the direct bandgap was found to be 5.17 eV. In addition, HRSEM analysis shows that the green synthesized ZnO NPs were well agglomerated and homogeneous; from the average particle size of ZnO NPs was found to be 25 nm. In the application point of view, supercapacitor properties of ZnO NPs was analyzed by cyclic voltammetry (CV) behavioral studies and electrolyte can be found using Electrochemical Impedance Spectroscopy (EIS). The zone inhibition of ZnO NPs on different gram positive, gram negative bacteria's and fungal microorganism shows excellent antimicrobial effects on the antimicrobial studies.

Influence of Frequency-Dependent Dielectric Loss on Electrorheology of Surface Modified ZnO Nanofluids

The shear dependent viscosity change in dielectric nanofluids under the applied electric field, provide potentials for prospect applications especially in enhanced oil recovery. When nanofluids are activated by an applied electric field, it behaves as a non-Newtonian fluid under electrorheological effect (ER) by creating the chains of nanoparticles. In this research, the effect of dielectric loss on the electrorheological characteristic of dielectric nanofluids (NFs) was studied, corresponding to the applied frequency of 167 and 18.8 MHz. For this purpose, electrorheological characteristics of ZnO (55.7 and 117.1 nm) nanofluids with various nanoparticles (NPs) concentration (0.1, 0.05, 0.01 wt. %) were measured. The measurement was done via solenoid based EM transmitter under salt water as a propagation medium. The result shows that the applied electric field caused an apparent increase on the relative viscosity of ZnO NFs due to electrorheological effect. However, the relative viscosity shows a higher increment at 167 MHz due to the greater dielectric loss, compared to 18.8 MHz. The high dielectric loss allows the dipole moments to rotationally polarize at the interfaces of nanoparticles, which create stronger chains that align with the applied electric field. Additionally, the relative viscosity demonstrated an increment with the increase in particle size of ZnO nanoparticles from 55.7 to 117.1 nm. While the viscosity of nanofluid also indicated the high dependence on particle loading.

Zinc oxide nanoparticles: solvent-free synthesis, characterization and application as heterogeneous nanocatalyst for photodegradation of dye from aqueous phase

In present study, for the first time, ZnO nanoparticles have been synthesized via a simple, novel, solvent and template free solid-state thermal decomposition of the mixed Zn(NO3)·6H2O and cochineal powders as a novel starting reagent at 600 °C for 3 h. The as-prepared product was analyzed by XRD, EDS, SEM, TEM, FT-IR and DRS. Besides, the effect of cochineal powder on the morphology and particle size of ZnO nanoparticles was investigated. The results exhibited that cochineal powder prevents the sintering of nanoparticles and leads to formation of uniform particles. Moreover, the efficiency of ZnO nanoparticles as a photocatalyst for the decolorization of methylene orange (MO) has been evaluated and 90% degradation of MO was obtained after 120 min.

Annealing effects on the structural and optical properties of ZnO nanoparticles with PVA and CA as chelating agents

The effects of annealing temperatures and chelating agents on the structural and optical properties of ZnO nanoparticles were investigated. The average particle size of ZnO nanoparticles increased with increase of annealing temperatures. The decrease of the full width at half maximum (FWHM) with increasing annealing temperatures inferred increase of particle/grain growth. The grain sizes were also observed to be increased with increase of annealing temperatures. From the absorption spectra of the samples, the absorption was red-shifted and the energy band gap was blue-shifted with increase of annealing temperatures. A sharp UV emission peak was observed and the intensity of this peak increased with annealing temperatures corresponding to the high crystallinity in the samples. At high annealing temperature of 700°C, ZnO exhibited a less intense deep level emission. This negligible deep level emission was attributed to the oxygen vacancies created at higher annealing temperatures.

Synthesis, characterization and bactericidal property of chitosan-graft-polyaniline/montmorillonite/ZnO nanocomposite

We synthesized the nanocomposite of chitosan-graft-polyaniline/montmorillonite/zinc oxide (CTS-g-PANi/ MMT/ZnO). ZnO nanoparticles (NPs) were successfully synthesized from ZnO powder in the Cts/MMT matrix, using traditional method. CTS-g-PANi co-polymer was synthesized in the presence of ammonium peroxydisulfate (APS). The CTS-g-PANi and MMT were used as the natural polymeric stabilizer and the solid support, respectively. The mor- phology and the particle size of ZnO NPs and synthesized nanocomposite were investigated by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). According to the XRD results, the nanoparticle size was found to be in the range of 22-35 nm. SEM images showed the hexago- nal shape of ZnO NPs, which is suitable for the evaluation of antibacterial activity. Finally, the bactericidal property of prepared nanocomposites was also evaluated against the bacteria of Gram positive Staphylococcus aureus (Staph.) and Gram negative Escherichia coli (E. coli), using the paper disc diffusion method.

Cure Characteristics and Mechanical Properties of ZnO Nanoparticles as Activator in Unfilled Natural Rubber

In this work, the effect of ZnO nanoparticles as activator is studied in unfilled natural rubber and compared with conventional ZnO on cure characteristics and mechanical properties. ZnO nanoparticles are synthesized by precipitation method using zinc nitrate tetrahydrate and sodium hydroxide as precursor. Particle size of ZnO nanoparticles can be controlled by polymeric additive. It is found that the average primary size of synthesized ZnO nanoparticles around 28.71 nm and the specific surface area around 31.45 m2/g. The crystalline structure exhibits hexagonal structure with wurtzite. The rheological properties of unfilled natural rubber show that the maximum torque (MH) and the optimum cure time (t90) increase with increasing synthesized ZnO nanoparticles loading. The minimum torque (ML) of unfilled natural rubber which uses synthesized ZnO nanoparticles loading higher than conventional ZnO. Compression set and tension set are the permanent deformation also investigated. It is found that deformation reduces when increase synthesized ZnO nanoparticles loading. The mechanical properties such as hardness, tensile strength, 100% and 300% modulus, tear strength, elongation at break are improved, without detrimental effect on properties. For unfilled natural rubber, synthesized ZnO nanoparticles can be reduced successfully from 5 to 2 phr and stearic acid 1 to 0.3 phr, respectively.

ZnO Doping in PET Matrix Enhances Conductivity of PET-ZnO Nanocomposites

Nanoparticles of ZnO are synthesized by chemical route and have been embedded in Polyethyline Terephthelate (PET) matrix via solution casting method. The shape and particle size of ZnO nanoparticles have been found to be spherical with average diameter 17.3 nm using TEM techniques. The morphology of PET-ZnO nanocomposites have been observed by SEM. With the help of UV-Vis spectrophotometer, increasing absorption of PET-ZnO nanocomposites has been found. With increasing ZnO particle concentration in PET matrix, band gap of nanocomposites decreases as well as ZnO nanoparticles cause to improve UV protection property of PET. Through electrical measurements, it has been observed that PET becomes conducting after incorporation of ZnO nanoparticles. The nature of vibrations of chemical bonds in PET-ZnO nanocomposites have been analyzed using Raman spectrometer as a result of ZnO doping in PET matrix.

Williamson-Hall analysis in estimation of lattice strain in nanometer-sized ZnO particles

Abstract ZnO nanoparticles were prepared by coprecipitation method at 450C. X-ray diffraction result indicates that the sample is having a crystalline wurtzite phase. Transmission electron microscopy (TEM) result reveals that the ZnO sample is spherical in shape with an average grain size of about 50nm. X-ray peak broadening analysis was used to evaluate the crystalline sizes and lattice strain by the Williamson-Hall (W-H) analysis. All other relevant physical parameters such as strain, stress, and energy density values were also calculated using W-H analysis with different models, viz, uniform deformation model, uniform deformation stress model and uniform deformation energy density model. The root mean square strain was determined from the interplanar spacing and strain estimated from the three models. The three models yield different strain values; it may be due to the anisotropic nature of the material. The mean particle size of ZnO nanoparticles estimated from TEM analysis, Scherrers formula and W-H analysis is highly intercorrelated.

Effect of annealing temperature and pH on morphology and optical property of highly dispersible ZnO nanoparticles

Highly dispersible zinc oxide nanoparticles were produced in large quantity via a simple solution method. The effect of temperature and pH impact on as-prepared ZnO nanoparticles with respect to the morphological and optical characteristics has been investigated. The average particle size of ZnO nanoparticles increased with increasing annealing temperature. A sharp UV band-edge emission was observed in as-prepared ZnO nanoparticles with negligibly less intense deep level emission. However, upon annealing at high temperature in air, UV band-edge emission disappears with an evolution of a broad deep level emission in photoluminescence spectra. Similarly, by adjusting the pH of reaction medium from 4 to pH = 8 using ammonium hydroxide solution, particle size gets bigger and bigger leads to red-shift in UV band-edge emission and an appearance of deep level emission peak. At pH = 8, well resolved sharp X-ray diffraction peaks were observed with lower FWHM values due to higher crystallite sizes.