International Journal of Nano Dimension
Volume:5 Issue: 1, Winter 2014

A set of multicomponent perovskite oxide nanoparticles based on La1-xSrxCo1-yFeyO3-δ(LSCF) were prepared by a simple chemical precipitation method for application in low temperature solid oxide fuel cells (LT-SOFC) as cathode materials. The precursor materials used in this synthesis were lanthanum nitrate hexahydrate [La(NO3)3.6H2O], strontium nitrate [Sr(NO3)2], cobalt nitrate hexahydrate [Co(NO3)2.6H2O], ferric nitrate nonahydrate [Fe(NO3)3.9H2O] [as basic materials] and sodium hydroxide [as precipitator material] and PVA [as surfactant]. Throughout the experiment, pH was maintained as pH > 9 by the addition of alkali (NaOH). A mixture of metal hydroxides (brown coloured) was formed when the aqueous mixture of basic materials mixed with the aqueous precipitant (NaOH) solution in proper stoichiometric compositions. The resultant hydroxide mixture was washed with ethanol and water mixture (1:9 volume %) to remove any unwanted impurities present along with the precipitate. The purified precipitate was dried at 50 – 100oC and heat treated at 300oC, 450oC, 600oC and 750oC for 2 hours each to get phase pure composite oxide powder. The resultant powder was characterized with TGA / DTA, XRD, FT-IR, Particle Size analysis and SEM. From the results, it was found that the chemical precipitation can be used effectively to prepare phase pure multicomponent perovskite oxides for application in SOFCs.

In this study, an efficient and facile technique for preparing graphene oxide in suspension and powder forms was presented based on a modification on Hummers'' method followed by an additional ultrasonic process. The method involved the provision of graphene oxide from graphite by reaction of potassium permanganate and sulfuric acid with stabilizing the medium complex. Furthermore, this study evaluated the functionality of graphene oxide in powder form in comparison with suspension using Fourier transform infrared spectroscopy. In addition, prepared graphene oxide powder was characterized using X-ray diffraction method for investigating the exfoliation of graphite to graphene nanosheets. Moreover, transmission electron microscopy and atomic force microscopy techniques were employed to demonstrate the structure of resulting graphene oxide in suspension form. The presence of graphene oxide nanosheets including an average thickness of about 2-4 nm was proved via microscopy observation of the prepared nanosheets.

Hospital wastewater has special importance since having pathogens, radioactive materials, pharmaceutical wastes and heavy metals. Removing them into environment without any treatment may cause serious problems for the public health. Membrane Biological Reactor is the combination of the activated sludge and membrane filters. This research has investigated the performance of the Nano-Filtration in a Membrane Biological Reactor (NF-MBR) in the pilot scale in comparison to the activated sludge system which is very common in hospitals and has been utilized in the Babol hospital`s wastewater treatment plant. NF-MBR pilot make the chance for the biological process to act in long SRT (in this case 62 days). Therefore the MLSS concentration in the aeration tank reach to over 6000 mg/l. TDS and EC removal is obtained 60% and turbidity and TSS removal is obtained up to 99%. The advantageous of this system were having no sludge removal in the experimental period, no chemical backwash of the nano-membranes and excellent and nearly constant quality of the effluent.

Nanostructured alumina thin films were coated on stainless steel by Sol-Gel dip coating method. In order to prevent crack formation, Al2O3 films were kept in a solvent bath immediately after coating to reduce the rate of drying. Effects of calcination temperature and withdrawal speed on structural properties were analyzed using XRD and SEM. Topography and thickness of coatings were analyzed by AFM. Effects of the above parameters on anticorrosion performance of coats have been evaluated through electrochemical polarization technique. The results indicated that the optimum calcination temperature to achieve the best corrosion protection was 400ºC. The thickness of one time coating with 1mm/s withdrawal speed was about 146 nm.

Copper (II) phthalocyanine and 2,9,16,23 tetrakis nitro copper (II) phthalocyaninehas been synthesized respectively from phthalonitrile and 4-nitro phthalonitrile under solvent-free condition using two different catalystsovernanodimensionalzeolites. 4-Nitro phthalonitrile synthesized from phthalimide in three steps. The newly prepared compounds have been characterized by IR, UV-Vis, 1HNMR and MS spectra.

B1-xLaxFeO3 (x = 0.0, 0.025) crystallites were prepared by chemical solution route. XRD analysis confirmed the phase formation of the materials. Thermal characterization was done by DSC-TGA to confirm crystallization and thermal behavior for phase development. Morphological studies by FESEM showed the agglomerated nature of the ferrite and EDX analysis confirmed the degree of doping. FTIR studies were done to determine the molecular signature of both undoped and doped sample.

Statistical methods، and especially machine learning، have been increasingly used in nanofluid modeling. This paper presents some of the interesting and applicable methods for thermal conductivity prediction and compares them with each other according to results and errors that are defined. The thermal conductivity of nanofluids increases with the volume fraction and temperature. Machine learning models were proposed to represent the thermal conductivity as a function based on the temperature، nanoparticles volume fraction and the thermal conductivity of the nanoparticles. The results of models were in appropriate agreement with the experimental data. This work represents 8 machine learning models for the predicting the thermal conductivity of water-based nanofluids. The models have been trained and tested on two separate sets of data. Three metrics have been employed to evaluate the performance of the models. The best method for each system is selected using results.

In this work, we report, optical properties of Cd1-xSnxTe quantum dots (x= 0.05, 0.10 and 0.15) synthesized in water using thioglycolic acid (TGA) as a modifier agent. The optical characterization of the samples was performed through absorption (UV) and photoluminescence spectra (PL). A red shift absorption and fluorescent emission peaks was observed which can be related to the increase of nanocrystals diameter with pass the reaction time. This size dependent phenomenon is concerned to the known “quantum confinement” effect and the highest quantum yield has been achieved under our experimental conditions (using thioglycolic acid (TGA) as a modifier agent) when the processing time reached to 150 min.

By employing the theoretical method based on tight-binding, we study electronic band structure of single-wall carbon nanotube (CNT) superlattices, which the system is the made of the junction between the zigzag and armchair carbon nanotubes. Exactly at the place of connection, it is appeared the pentagon–heptagon pairs as topological defect in carbon hexagonal network. The calculations are based on the tight binding model in the nearest-neighbor approximation. We seek to describe electronic band structure in the presence of the pentagon-heptagon pairs. Our calculation show that the pentagon–heptagon pairs defect in the nanotube structures is not only responsible for a change in a nanotube diameter, but also governs the electronic behaviour around Fermi level. Also, we obtain the Fermi energy of the system via integration of the density of states and matching it to the number of electron in the unit cell. The numerical results may be useful to design of electronic devices based on CNTs.

Zeolites due to their structures can be used as molecular sieves for purification of materials and solutions. Zeolites with PHI and SOD structure are so common and applicable for this purpose. Hydroxy sodalite and phillipsite are the more abundant members of zeolites which display good selectivity for very small molecules and some ions such as Sr, Pb, Zn, Cu and Rb. There is not any pure natural deposit of these zeolites and purify methods are not cost-effective. Therefore, introducing an effective method to prepare these zeolites is necessary. In this study, hydroxy sodalite and phillipsite have been synthesized respectively from clinoptilolite and volcanic ash at hydrothermal conditions in the presence of alkaline solutions. Mineralogical studies show that K, Na and Cl ions are necessary in SOD and PHI structure. The effect of K+ concentrations and temperature in the presence of constant value of Na+ and Cl-are being considered as the variable parameters in the present experiment. NaCl used as source of Na+ and Cl- ions. Alkaline solutions were prepared by using 2 to 12 grams KOH powder and synthesize mixture were heated at temperatures of 100 and 150˚C. Results of this study show that phillipsite is synthesized at 100 and 150˚C in all runs. Hydroxy sodalite is appeared just in 150˚C by using clinoptilolite as initial material. Analcime formed as by-product of volcanic ash phase transition at 150˚C.

The present work is focused on the degradation of 4-chloro-2-nitrophenol in aqueous solution containing nano titanium dioxide, hydrogen peroxide and the combination of nano-TiO2/H2O2. The effect of experimental parameters, such as the amount of nano- TiO2 concentration of H2O2, initial concentration of 4-chloro-2-nitrophenol and pH on the reaction was investigated. Experimental data obtained under different conditions describe the dependency of degradation rate on the above mentioned parameters. The optimum conditions of the degradation treatment were: [H2O2]=100 mg/L; [nano- TiO2]=0.004 g/250 mL; initial pH=10 and initial 4-chloro-2-nitrophenol concentration=15 mg/L. Consequently, kinetic parameters were experimentally determined and a pseudo-first-order kinetic was observed.

A PEBAX-nano zeolite X mixed matrix membrane was fabricated and operationally characterized using single gas (CO2) permeation. X-ray diffraction (XRD) analysis was used to study the arrangement of polymer chains of mixed matrix membrane. The membranes were characterized by scanning electron microscopy (SEM) to study cross-sectional morphology. The single gas permeability were carried out for neat PEBAX and PEBAX-nano zeolite X (10 wt. %) membranes. Operating pressures varied from 6 to 14 bars. CO2 permeability for the nano-composite membrane was higher than the neat polymer membrane and increased with pressure. Adding 10 wt.% of nanozeolite X into the polymeric matrix caused CO2 permeability to increase. Both structurally and operationally characterizations revealed the defect-free structure of the nano composite membrane.

Zeolite FAU type-Y is one of the most studied framework of all zeolites, and has been used as catalysts for number of reactions in the refinery and petrochemical industry. In this research, nanocrystalline zeolite Y was synthesized by hydrothermal method. The crystal size of zeolite Y is influenced by temperature, aging time, alkalinity, and water content. The synthesized zeolite NaY is identified and characterized by Brunauer-Emmett-Tell (BET), Fourier Transmission Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). The mean crystallites size was measured by transmission electron microscopy (TEM) and it was determined also by Rietveld''s method using Scherrer''s equation; with similar results estimated was about 50 nm.