JOURNAL OF NANOSTRUCTURES
Year:2016 | Volume:6 | Issue:3|Papers Count:10

Introduction of the nanoparticles in the bulk glass received a large interest due to their versatile application. The composition of Er+3-doped Zinc-Lead-Phosphate glass samples are prepared by melt-quenching technique. The structural and optical properties of phosphate glass have been examined by x-ray diffraction, field emission scanning electron microscopy, photoluminescence spectroscopy and UV-Vis-NIR scanning spectrophotometer. The x-ray diffraction pattern has confirmed their amorphous nature and the field emission scanning electron microscopy micrograph showed the distribution of nanoparticles in glass. The study indicates that doped SnO2 nanoparticles have an influence on the band gap energy that decreases with the increasing amount of nanoparticles.The photoluminescence spectra showed three peaks at the green-orange region of the visible spectrum and four times enhancement for doped 0.25% SnO2 nanoparticles. The enhancement in the luminescence intensity of the green-orange region is found to be due to the effective local field of nanoparticles. The optical properties motivate to use these glassed as novel luminescent optical materials.

In this experimental work, PbS/ZnS/ZnO nanocomposite was synthesized via a simple co-precipitation method. The effect of Zn2+/Pb2+mole ratio was investigated on the product size and morphology. The products were characterized via scanning electron microscopy to obtain product size and morphology. The optical properties of the nanocomposites were studied by ultra violet-visible spectroscopy. Photocatalytic activity of the product was examine by decomposition of acid black 1 as dye. To investigation of the effect of as synthesized nanocomposite on the water treatment, the influences of the nanocomposite to remove heavy ions was studied by atomic absorption spectroscopy. The results showed that the synthesized nanocomposite has well optical properties, photocatalytic and water treatment activities.

In the present study, ZnO nanostructure has been synthesized by different methods, namely coprecipitation, hydrothermal and sonochemical methods. After comparison of the morphology and photocatalytic activity of ZnO samples prepared via different methods, the best method (sonochemical method) was used for synthesis of Ni-ZnO nanoparticles with different concentrations of nickel. Furthermore, structural and optical properties were investigated by Fourier Transform Infrared spectroscopy, UV–Vis spectroscopy, Field Emission Scanning Electron Microscopy, X-Ray Diffraction, and Photoluminescence spectroscopy methods.Morphology of nanoparticles prepared via sonochemical method were obtained small granular shape. In addition, the direct band gap has been calculated by Tauc's approach. Compared with pure ZnO, the band gap of the Ni-ZnO NPs is smaller and depends on the content of dopants.Moreover, photocatalytic activity of all samples has been investigated under UV irradiation in an aqueous medium. In addition, photocatalytic activity is improved in the presence of an appropriate amount of nickel dopant.

In the present study, the application for the removal of phenylalanine by using two nano sorbents, namely, cetyltrimethylammonium bromide –Coated and BKC (benzal-conium chloride) -Coated Fe3O4 nanoparticles was investigated. Solid-phase extraction (SPE) and ultra violet–visible spectroscopy were used for studying the removal ability of each nanosorbent in this study. Scanning Electron Microscopy, X-ray diffraction and Fourier infrared were used to characterize the synthesized magnetite nanoparticles. Batch adsorption studies were carried out to study the effect of various parameters, such as contact time, solution pH and concentration of phenylalanine. The equilibrium adsorption data of phenylalanine onto Fe3O4 nanoparticles (non-functionalized sample), cetyltrimethylammonium bromide -Coated and BKC -Coated were analyzed using Freundlich and Langmuir adsorption isotherms. The results indicated that adsorption of phenylalanine increased with increasing solution pH and maximum removal of phenylalanine was obtained at pH=9.0. Correlation coefficient were determined by analyzing each isotherm. It was found that the Freundlich equation showed better correlation with the experimental data than the Langmuir.

In this research zinc sulfide (ZnS) nanoparticles and nanocomposites powders were prepared by chemical precipitation method using zinc acetate and various sulfur sources. The ZnS nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible and fourier transform infra-red. The structure of nanoparticles was studied using X-ray diffraction pattern. The crystallite size of ZnS nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the scanning electron microscopy. The grain size of zinc sulfide nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. The optical properties of particles were studied with ultraviolet-visible absorption spectrum.

Up to now, researchers have proposed several synthesis methods for the preparation of b -nickel (II) hydroxide nanostructures. Most of these approaches contain harsh synthetic conditions such as multi-step processes, high temperatures and long reaction time. In this work, a novel, facile and low cost method is introduced to produce of b-Ni (OH)2 nanostructures using the gas-solution precipitation from nickel (II) sulfate solution in the presence of anionic or cationic surfactant upon exposure to ammonia gas at room temperature. Herein, no other additive is needed and the method is suited for large-scale preparation. The structural characterizations were carefully investigated by the powder X-ray diffraction technique and Fourier transformation infrared spectroscopy. Further, the scanning electron microscopy results showed the important roles of the sodium dodecylsulfate and cetyltrimethylammonium bromide on the morphology and size of the products. The calcination process of hydroxide samples was also conducted to synthesize nickel (II) oxide nanostructures.

In this work, Pt, Fe and Co nanoparticles were prepared by chemical reduction of the metal salts in chitosan as the support. NaBH4 was used as the reducing agent Pt-Fe, Pt-Co and Pt-Fe-Co-chitosan nanocomposites were synthesized and characterized by UV–Vis spectra and Transmission electron microscopy images. GC/Pt-chitosan, GC/Pt-Co-chitosan, GC/ Pt-Fe-chitosan and GC/Pt-Co-Fe-chitosan electrodes were prepared.The performances of these electrodes for methanol electrooxidation were investigated through cyclic voltammetric and chronoamperometric curves. The effect of some experimental factors such as the amounts of Fe and Co nanoparticles dispersed in chitosan, methanol concentration and scan rate were studied and the optimum conditions were determined.The effect of temperature was also investigated and the activation energies were calculated. The performance of Pt-Fe-Co-chitosan nanocomposites was determined in a direct methanol fuel cell in different conditions.The electrochemical and fuel cell measurements showed that Pt-Fe-Cochitosan nanocatalyst has the best activity for electrooxidation of methanol among all different compositions electrodes.

Over the past years, DNA biosensors have been developed to analyze DNA interaction and damage that have important applications in biotechnological researches. The immobilization of DNA onto a substrate is one key step for construction of DNA electrochemical biosensors. In this report, a direct approach has been described for immobilization of single strand DNA onto carboxylic acid-functionalized carbon nanotubes modified glassy carbon electrode. To do this, we first modified the glassy carbon electrode surface with MWCNT-COOH. The immersion of MWCNT-COOH/ GCE in ss-DNA probe solution, with different pH and ionic strength, was followed by suitable interaction between amine group of ss-DNA bases and carboxylic groups of MWCNT-COOH. This interaction leads to successful ss-DNA immobilization on MWCNT-COOH that was confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and atomic force microscopy. Immobilization of ss-DNA on the modified electrode increased the charge transfer resistant but decreased the peak current of redox probe ([Fe (CN)6] 3-/4-). The result of cyclic voltammograms implicates that enhancements in the DNA immobilization are possible by adroit choice of low pH and high ionic strength. The standard free-energy of adsorption ( DGoads) was calculated from electrochemical impedance spectroscopy data (-47.75 kJ mol-1) and was confirmed covalent bond formation. atomic force microscopy topographic images demonstrate increased surface roughness after ss-DNA immobilization. Results offer a simple, rapid and low-cost of DNA immobilization strategy can be opportunities to design of novel nucleic acid biosensors.

In this study, molecularly imprinted polymers were synthesized for dibutyl phthalate as a bioactive chemical compound with antifungal activity which produced by Trichoderma Harzianum (JX1738521). The molecularly imprinted polymers were synthesized via precipitation polymerization method from methacrylic acid, dibutyl phthalate and trimetylolpropantrimethacrylate as a functional monomer, template and cross-linker, respectively. After removal of the template by the eluent from the MIPs, the leached nanoparticles of the MIPs had a good binding capacity as equal 830 mg/g. The polymer particles have been evaluated by field emission scan electron microscopy and Brunauer–Emmett–Teller techniques. The excellent specific surface area in the molecularly imprinted polymers as equal to 690.301 m2/g comparatively to nonimprinted polymers (ca.89.894 m2/g), confirms that the nanoporous MIPs were synthesized, successfully. The results indicated that the nanoporous MIPs can be used in solid phase extraction. This is a novel method for separation of the bioactive compounds from fungi secondary metabolites in biological control.

In this present study reports the green synthesis of zinc oxide nanoparticles using Betel leaf extracts and zinc acetate. The functionalization of ZnO particles through Betel leaf extract mediated bio reduction of ZnO was investigated through X-ray diffraction, Field emission scanning electron microscopy, photoluminescence, thermal gravimetric-differential thermal analysis, hexagonal shaped ZnO-nanoparticles with size about 50 nm were synthesized and characterized using X-ray diffraction analysis.The diameter of the nanoparticles in the range of 50 nm was found from scanning electron microscopy study. Photo luminescence study reveals the blue emission at 463nm respectively. hermal gravimetricdifferential thermal analysis show that the observed at 480oC, indicating that no decomposition occurs above this temperature. The photocatalytic degradation of methylene blue dye was examined using ZnO nanoparticles under solar as well as ultra violet light irradiation of the MB dye. The method stands out primarily due to the fact that it is eco-friendly and shuts down the demerits of conventional physical and chemical methods.These particles are anticipated to have extensive applications in various industries.