Due to distinguishing characteristics of nanoparticles (NPs) in terms of size, shape, chemical composition, transmittal and different applications, nanotechnology is considered as an interesting domain of research. Application of metallic NPs is important because of the diminution of dimensions and thus the unique thermal, optical and electronic properties. This research attempts to explore the synthesis of zinc oxide NPs. Zinc oxide NPs have been synthesized using cherry extract under different pH, temperature and concentration and then optimum conditions for the synthesis of them were determined. For further investigations, UV-Vis spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier infrared transformation spectroscopy (FTIR) were used. The solution containing zinc oxide NPs showed a major absorbance of 378 nm which confirmed the synthesis of zinc oxide NPs, and spherical morphology of NPs was observed in SEM images. Zinc oxide NP sizes were 6.5 and 20.18 nm which are obtained by UV-Vis spectra and XRD spectrum, respectively. Also, based on the FTIR spectra of the extract obtained before and after the synthesis, the existence of the reducing agents in herbal extract was confirmed. According to this study, the biological synthesis of NPs using plant extracts can be considered as a cost-effective and efficient method of biological synthesis of NPs and it could be an appropriate replacement to typical chemical methods for the synthesis of NPs.

ZnO plays an important role in many technological aspects of semiconductors. Because of its interesting properties, it has attracted a great deal of attention for a wide range of applications. In this work, the direct precipitation method was employed for the synthesis of ZnO nanoparticles to study the role of different concentration ratios of reactants on the crystal structure, size, and morphology of the prepared ZnO nanoparticles. The reactant raw materials used in this experiment were zinc acetate dihydrate as a zinc source and NaOH. ZnO nanoparticles were synthesized by calcination of the ZnO precursor precipitates at 250°C for 3 h. These calcinated ZnO nanoparticles and their properties were characterized using X-ray diffraction, a scanning electron microscope equipped with an energy dispersive X-ray spectrometer, and transmission electron microscopy. We present the experiment conditions, including result on the different reactant concentration ratios, which affect the control of the size and morphology of the ZnO nanoparticles. The mean size of the ZnO nanoparticles was 18 nm.

In this study, direct precipitation technique was used to synthesize Ag nanoparticles supported by carbon nanotubes. After distinguishing the best situation in the synthesis of Ag nanoparticles, carbon nanotubes as the support were used to control the Ag nanoparticle size. The prepared carbon nanotubes and Ag nanoparticles were investigated by using X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. The results showed that carbon nanotubes can play an important role in controlling the morphology and size of the obtained powders, and the size of Ag nanoparticles synthesized on the carbon nanotubes is smaller.

We propose chlorpromazine (CHP) as a new mediator for the rapid, sensitive, and highly selective voltammetric determination of homocysteine (Hcy) using multiwall carbon nanotube paste electrode (MWCNTPE). The experimental results showed that the carbon nanotube paste electrode has a highly electrocatalytic activity for the oxidation of Hcy in the presence of CHP as a mediator. Cyclic voltammetry, double potential step chronoamperometry, and square wave voltammetry (SWV) are used to investigate the suitability of CHP at the surface of MWCNTPE as a mediator for the electrocatalytic oxidation of Hcy in aqueous solutions. The kinetic parameters of the system, including electron transfer coefficient, and catalytic rate constant were also determined using the electrochemical approaches. In addition, SWV was used for quantitative analysis. SWV showed wide linear dynamic range (0.1–210.0 μM Hcy) with a detection limit of 0.08 μM Hcy. Finally, this method was also examined as a selective, simple, and precise electrochemical sensor for the determination of Hcy in real samples.

In this study, the efficiency of nickel oxide/carbon nanotube (NiO/CNT) nanocomposite to remove Pb 2? from aqueous solution is investigated. NiO/CNT nanocomposite was prepared using the direct coprecipitation method in an aqueous media in the presence of CNTs. Samples were characterized using simultaneous thermal analysis (STA), X-ray diffraction (XRD), filed emission scanning electron microscopy (FESEM), and BrunauerEmmett-Teller (BET). To optimize the adsorption of Pb 2?ions on NiO/CNT nanocomposite, the effects of different parameters including pH, contact time, initial concentration of Pb 2? , and adsorbent mass-were also investigated. The optimum Pb 2? removal efficiency on NiO/CNT nanocomposite is achieved under experimental conditions of pH 7, contact time of 10 min, initial Pb 2? concentration of 20 ppm, and adsorbent mass of 0.1 g. The experimental data showed that the Pb 2? ions adsorption of NiO/CNT nanocomposite was through a Freundlich isotherm model rather than a Langmuir model. The kinetic data of adsorption of Pb 2? ions on the adsorbent was perfectly shown by a pseudo-second-order equation, to indicate their chemical adsorption. Thermodynamic parameters such as DG°, DH°, and DS°were also measured; the obtained values showed that the adsorption was basically spontaneous and endothermic.