فهرست مطالب

Nano Structures - Volume:8 Issue: 1, Winter 2018

Journal of Nano Structures
Volume:8 Issue: 1, Winter 2018

  • تاریخ انتشار: 1396/12/21
  • تعداد عناوین: 12
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  • Zahra Sahebnazar, Dariush Mowla *, Gholamreza Karimi Pages 1-10
    The application of iron-silica (Fe-Si) nanoparticles for the enhancement of the Pseudomonas aeruginosa growth and rhamnolipid production in molasses medium was studied. The experiments were designed based on the response surface method (RSM) to optimize growth and rhamnolipid production. The concentration of nanoparticles and the time required to add nanoparticles to culture medium were considered as independent variables. The dry weight of cell, the dry weight of rhamnolipid and the surface tension were measured as response variables. In addition, to determine a basic and low-cost medium, the concentrations of molasses and NaCl as components of medium were optimized by RSM. The optimum medium was estimated to include 15% of molasses without NaCl. The results showed that the highest increase in the growth of P. aeruginosa is 25% which occurred at 600 mg/L of nanoparticles and 18 h of addition time compared to the free-nanoparticles experiment. In the same way, the highest increase in rhamnolipid production was 57% at 1 mg/L of nanoparticles and 6 h of addition time compared to blank experiment. TEM images of the morphology changes of bacteria demonstrated the permeation of nanoparticles into the inbound cells. Results of this study reveal the great potential of Fe-Si nanoparticles to overcome the difficulties of the rhamnolipid production in industrial scale.
    Keywords: Addition time, Bacteria growth, Biosurfactant production, Nanoparticles concentration, Rhamnolipid
  • Dhanashri Patil, Vinita Deo, Shanabhau Bagul, Priyanka Patil, Prabhakar Sonawane, Madhav Wagh * Pages 11-20
    ZnO nanorods were prepared using dimethylamine (DMA) controlled Sol-Gel process. Dimethylamine was added as an additive to control the sol-gel process for growing ZnO nanorods. DMA would exhibit stabilizing effect, promote dissolution of precursor and control the rate of sol-gel reactions because of its basic nature and significant miscibility. The Structural and microstructural properties of the powders were characterized by X-Ray Diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). FESEM and TEM analysis revealed that the ZnO powder prepared were nanorods in nature. The optical properties of powders were characterized by UV-Visible and Photoluminescence (PL) spectroscopy. The Structural, morphological, optical and photoluminescence properties of so obtained ZnO powders consisting of nanorods were studied. DMA is simple amine but found to be very effective to control the aspect ratio of nanorods. The role of DMA in growing wurtzite structured hexagonal ZnO nanorods with [0001] orientation was interpreted and growth mechanism of ZnO nanorods was explained.
    Keywords: Nanostructures, Nucleation, Sol-gel growth, ZnO nanorods
  • Mohammad Hasanzadeh *, Ayub Karimzadeh, Nasrin Shadjou Pages 21-30
    L-Tryptophan (L-Trp) is of great importance in the biochemical, pharmaceutical and dietetic fields as it is precursor molecule of some hormones, neurotransmitters and other relevant biomolecules. So, determination of this amino acid has important role in detection of some neuron based disease. The main purpose of this report was to develop application of Fe3O4 magnetic nanoparticles/graphene quantum dots (Fe3O4 MNP-GQDs)) as a nanosensor towards electrooxidation and determination of L-Trp and also the evaluation its kinetic parameters. In continuation of our efforts to use Fe3O4 MNP-GQDs for amino acids detection, our objective in the present work was to expand application of this sensor for the determination of L-Trp which is very sensitive. Decrease in oxidation overpotential and enhancement in current proved the electrocatalytic activity of Fe3O4 MNPs-GQDs-GCE as a sensor. Importantly, by this simple method of fabrication a much lower detection limit was achieved without involving any pre-treatment or activation steps. The analytical applicability of the modified electrode has been evaluated by successfully employing it for the determination of L-Trp in the standard solution.
    Keywords: Amino acid, Graphene quantum dot, L-Tryptophan, Magnetic nanoparticle
  • Hossein Ghasemi Mobtaker *, Taher Yousefi, Masoud Arabieh Pages 31-36
    Metal doped TiO2 catalysts were synthesized by sol-gel method and their activities were determined for degradation of methyl orang as a pollutant. Nd-doped TiO2 showed the maximum activity comparing with others. Colloidal SiO2 was used as a support to increase the surface area and also the activity. Nano-TiO2/SiO2/Nd was synthesized by sol-gel method and it was characterized using XRD, XRF, SEM, TEM and BET methods. The major phase of synthesized catalyst was anatase and the crystal size estimated about 30 nm which was confirmed by TEM. BET analysis showed that deposition of catalyst on colloidal silica, enhanced the surface area significantly. It was found that the solution pH has great effect on kinetic and efficiency of the degradation process. At low pHs the degradation rate was faster comparing with alkaline solutions. Applying various fields to enhance the kinetic and efficiency of the photochemical process was studied. It was found that electric field (EP) has the most significant effect. Ultrasonic (UP) and magnetic (MP) fields were also effective in some cases. LC MS analysis showed that mineralization could be completed at the end of process.
    Keywords: Doping, Electro-Photochemical, Magnetic-Photochemical, TiO2, Ultrasonic-Photochemical
  • Sadaf Samiei, Fatemeh Pakpour *, Davood Ghanbari Pages 37-46
    In this research we first synthesized MgFe2O4 nanostructures via hydrothermal method using (Mg(NO₃)₂.6H₂O) and (Fe(NO₃)₃.9H₂O). The influence of concentration, surfactant, precipitating agent and temperature on the particle size and magnetic properties of the synthesised nanoparticles were examined. Then MgFe2O4-Ag nanocomposites were prepared by a simple chemical precipitation. The structural characteristics of samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR). Spectroscopy vibrating sample magnetometer showed that the prepared ferrite nanostructures had ferromagnetic property. The photocatalytic aspects of MgFe2O4-Ag nanoparticles and nanocomposites were measured using the degradation of three azo dyes (acid red, acid violet and methyl orange) under ultraviolet irradiation. Our results confirm the successful formation of MgFe2O4 nanoparticles and MgFe2O4-Ag nanocomposite. It was also shown that the prepared nanostructures had appropriate magnetic properties and photocatalytic performance.
    In this research we first synthesized MgFe2O4 nanostructures via hydrothermal method using (Mg(NO₃)₂.6H₂O) and (Fe(NO₃)₃.9H₂O). The influence of concentration, surfactant, precipitating agent and temperature on the particle size and magnetic properties of the synthesised nanoparticles were examined. Then MgFe2O4-Ag nanocomposites were prepared by a simple chemical precipitation.
    Keywords: Magnesium Ferrite, Magnetic, Nanostructure, Nanocomposite, Photo-catalyst
  • Rahim Molaei, Khalil Farhadi *, Mehrdad Forough, Salaheddin Hajizadeh Pages 47-54
    The development of green and safe processes for the synthesis of nanomaterials is one of the main aspects of nanotechnology. In this study, a biological, inexpensive and rapid process for the fabrication of palladium nanoparticles using the aqueous broth of Pistacia Atlantica fruit as a novel biomass product is reported without using extra surfactant, capping agent, and template. The synthesized palladium nanoparticles were confirmed and characterized by various spectroscopic techniques including UV-Visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer, Fourier transform infrared spectroscopy and Zeta-potential measurement. The results indicate that the spherically shaped Pd nanoparticles were successfully prepared in aqueous media in accordance with the principles of green chemistry with desired stability and crystalline in nature with face centered cubic geometry. Also, the results of transmission electron microscopy (TEM) confirmed preparation of very stable nanoparticles with the small diameter below 15 nm.
    Keywords: Aqueous broth, Biological fabrication, Green, Palladium nanoparticles, Pistacia Atlantica
  • Sijo Francis, Ebey Koshy, Beena Mathew* Pages 55-66
    Here we reported the extremely simple one-pot synthesis of silver and gold nanoparticles in a rapid manner. Aqueous leaf extract of the most admired energy plant Jatropha curcas is used as reducing agent here. An alternate and safe energy source, house-hold microwave oven constituted the reaction chamber. Silver and gold nanoparticles were characterized by UV-visible, FT-IR, Powder XRD techniques. Surface plasmon resonance peaks corresponding to silver and gold nanoparticles were 428 nm and 543 nm respectively. The XRD patterns were indexed to reflections originated from (111), (200), (220) and (311) faces of FCC nanosilver and nanogold. Microscopic analysis revealed spherical geometry of silver nanoparticles with an average diameter 20.42±12.2 nm. Gold nanometals exhibited uneven shapes with average size 17.12±2.9 nm. In-vitro antioxidant potential assessment by DPPH model gave IC50 values 19.37±0.63 and 16.59±0.29 µg/ mL for silver and gold nanoparticles. The nanometals showed excellent bactericidal activity in agar well diffusion towards microorganisms namely Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Aspergillus nidulans and Aspergillus flavus. Degradation of methylene blue and rhodamine B by NaBH4 happened within 10 minutes in the catalytic presence of silver/gold nanoparticles offered a new means for purification of industrial dye effluents. Hydrogenation of 4-nitrophenol in presence of the prepared nanoparticles validated their catalytic utility. The reaction followed pseudo-first order kinetics with respect to reactant concentration.
    Keywords: Jatropha curcas, metal nanoparticles, Green synthesis, DPPH, well diffusion, dye degradation
  • Mustafa Aghazadeh* Pages 67-74
    Electrochemical synthesis followed by heat-treatment is a facile and easy method for preparation of nanostructured metal oxides. Herein we report nanostructured Mn5O8 prepared through pulse cathodic deposition followed by heat-treatment for the first time. For the preparation of Mn5O8 nanorods, pulse cathodic electrodeposition was first done from 0.005M Mn(NO3)2 at the current density of 5 mA cm-2 which yield Mn3O4 precursor. Then, heat-treatment of the deposited precursor was performed to obtain final Mn5O8 product. The structural and morphological properties of the prepared product were investigated by XRD, FT-IR, SEM and TEM techniques. The analysis results revealed that the prepared sample has pure Mn5O8 composition with rod morphology at nanoscale. Mechanism of deposit formation during pulse deposition was proposed and discussed. The formation of Mn5O8 nanorods via calcination of Mn3O4 precursor was also studied by thermogravimetric analysis. The results suggested that the cathodic electrodeposition-heat treatment method can be considered as simple and facile route for preparation of Mn5O8 nanorods.
    Keywords: Heat-treatment, Mn5O8 nanorods, Pulse electrodeposition
  • Faezeh Soofivand, Mohammad Sabet, Hamideh Seyghalkar, Masoud Salavati-Niasari * Pages 75-81
    Cobalt sulfide (CoS2) nanostructures were synthesized via a simple thermal decomposition method using [Co(oct)2] as a new precursor. Using the organometallic compound as precursor could synthesize materials in nano-scale because of having the massive structure that acted as capping agent. The products were characterized by various analyses such as X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FT-IR) spectroscopy. Also, the optical properties of this product was investigated by photoluminescence spectroscopy (PL). However, band gap of CoS2 nanostructures was estimated about 2.2 eV in this work but CoS2 was considered as a metallic product in the former work. This difference may be related to quantum effects in nanomaterials. The photocatalytic activity of CoS2 nanoparticles was examined by decolorization of Erythrosine as an organic pollutant under UV irradiation and degradation percent of this dye was reported about 84 %. According to the kinetics studies, the photocatalytic reactions are following the Pseudo first-order model.
    Keywords: [Co(oct)2], CoS2, Nanostructures, Photocatalyst, Pseudo first-order model, Thermal decomposition
  • Atena Alaghemand, Shahab Khaghani *, Mohammad Reza Bihamta, Masoud Gomarian, Mansour Ghorbanpour Pages 82-88
    zinc oxide nanoparticles have been synthesized using nigella sativa L. seed extract. Nigella sativa L. is an annual herbaceous plant belonging to the Ranunculaceae family. Concentration of plant extract plays a vital role in the synthesis of nanoparticles zinc oxide. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). This experiment was conducted in Arak University in an experiment based on randomized complete block design with four replications. Each replication consisted of one fertilizer levels including 2 per thousand of Zn-nanoparticles in one stages of growth (8 or 12 leaves). During the experiment, the height of plant, number of branches was investigated. This study showed that using spraying had significant differences in the factors like plant height number of branches. Also, using all microelement treatments had significant effects to the level of 1%. In case of using spraying treatments, the best results for number of branches and height were related to 2.perthousand of Zn- nanoparticles and the least were related to control. This formulation can be used for increasing yield, enhancing the products and removing food deficiencies.
    Keywords: Extract, Height, Nanoparticles, Nigella sativa L, ZnO
  • Ali Abbasi *, Mazyar Ahmadi Golsefidi, Mehdi Mohammad Beigi, Nazanin Sadri, Mehdi Abroudi Pages 89-96
    Co3O4 nanoparticles were synthesized via a simple Co-precipitation reaction between precursors of cobalt and NH3. The effect of different parameters such as concentration of NH3 and precursors of cobalt on the size and photocatalytic activity of the products was investigated. The achieved nanoparticles were characterized by X-ray powder diffraction analysis, field emission scanning electron microscopy, energy-dispersive spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS). The photocatalytic behavior of Co3O4 nanoparticles was evaluated using the degradation of various organic pollutants (rothamine B and methyl orange) under visible irradiation. Also effect of pH on the photocatalytic performance of Co3O4 nanostructures was investigated. Best concentration of NH3 for degradation of methyl orange and rhodamine B is 3 mol, and most appropriate precursor of cobalt for the demolition of dyes is Co(Hsal)2. Photo-degradation of Rhodamine B and methyl orange (89%) was performed using Co3O4 nanoparticle (band gap 1.7 eV) synthesized by Co(Hsal)2 as precursor of cobalt under visible light irradiation for 4h.
    Keywords: Co3O4, Methyl orange, Nanoparticle, Photocatalytic activity, Rhodamine B
  • Mohammad Hassanpour, Masoud Salavati-Niasari *, Seyed Alireza Mousavi, Hossein Safardoust-Hojaghan, Masood Hamadanian Pages 97-106
    CeO2/ZnO nanocomposites were synthesized by microwave method that is the fast process. One of an eco-friendly solvent, ethylene glycol were used the effect of time and power of irradiation were investigated on morphology and size of nanoparticle. Prepared CeO2/ZnO nanocomposites are characterized with X-ray diffraction (XRD) analysis, Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM) and UV–Visible absorption spectroscopy. For this nanocomposites photocatalyst test were applied against four colors, Methyl violet, Methylene blue, Rhodamin b and Erythrosine. the percent of decolorization for each color under UV light after 120 min were 92% and 60% were obtained respectively.
    Keywords: CeO2 - ZnO_Nanostructures_Microwave_Nanocomposites_Photocatalyst