جستجوی مقالات مرتبط با کلیدواژه « co-precipitation » در نشریات گروه « شیمی »

In this work, La2MnFe2O7 and La2CuFe2O7 photocatalysts were synthesized using a co-precipitation method. The surface morphology, structure, crystalline phase and magnetic behavior of the catalysts were investigated by TEM, FT-IR, XRD, DRS, and VSM. The photocatalytic activity of the La2MnFe2O7 and La2CuFe2O7 nanocomposites were appraised using the optical decomposition of malachite green oxalate (MG), methyl violet (MV), and Eriochrome Black T (EBT) beneath ultraviolet (UV) beam irradiance at different factors like the solution pH, dyes’ concentration, catalysts’ amount, temperature and time of UV light radiation. This research provided the synthesis of new composite magnetic photocatalysts and the study of their effectual in the field of photodegradation of dye pollutants.

In this study, ZnWO4:Er3+ nanocrystals were synthesized using a simple co-precipitation method. The structural properties of the prepared powders were characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM). The synthesized nanopowders exhibited a monoclinic wolframite crystal structure. Using the Williamson-Hall method, the lattice strain and crystal size of the synthesized powders were estimated. ZWO nanopowders with a 1 at.% concentration of Er dopant showed the lowest strain and crystallite size. FE-SEM results revealed that the prepared nanoparticles have a spherical morphology with an average size of 140 nm. The FTIR analysis confirmed the presence of Zn-O, Zn-O-W, and W-O vibrations in the synthesized structure. The transmittance percentage in the doped sample changed concerning the pure one, indicating that interstitial Er3+ ions affected the number of W-O, Zn-O, and Zn-O-W bonds. The facilely synthesized Erbium-doped ZnWO4 nanocrystals showed promise for a range of practical applications.

The co-precipitation method synthesized the synthetic anionicMg–Al and Ni-Al clays with three molar ratios (Mg/Al, Ni/Al). The samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). No other crys talline phases were detected in the powder XRD patterns of the co-precipitated samples. The infrared spectra obtained all the functional groups that characterize these two types of anionic clays. SEM micrographs indicate the presence of particles and aggregates. The particles, or aggregates, are in the form of plates, supported by particles of acceptable sizes. The optimal pH for maximum lead adsorption is about 6.5 for both clays. The optimal adsorbent masses for the maximum percentages of lead removal are 0.2 g for Mg3AlCO3 and 0.25 g for Ni3AlCO3. The Mg3AlCO3 has a maximum adsorption capacity of lead, where qm=73.42 mg g-1. The adsorbed amount increases with increasing temperature for both types of clays s tudied. The equilibrium time of Pb2+ adsorption is reached after 5 min for both clays. The mos t appropriate models to describe the experimental data of adsorption kinetics and isotherms are pseudo-second-order and Langmuir. The detection limit (LOD) was 0.272 mg L-1. The linearity range was 1 to 5 mg L-1; the correlation coefficient in this range was 0.9997.

A novel route for the synthesis of pure and nickel (Ni) doped copper oxide (CuO) nanoparticles via a simple co-precipitation process has been presented. The effect of the concentration of the dopant Ni (0, 2, and 4 mol %) on its properties has been carefully investigated. It has been reported that Ni doping is successfully achieved through the synthesis route. The structure and morphology were analyzed by using X-ray diffraction, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy. X-ray diffraction analysis proved that prepared nanoparticles are highly pure and crystalline having a monoclinic structure and the crystallite size increases (13 nm to 17 nm) with Ni doping. Fourier transform infrared spectrum show successful Ni doping in the CuO system. Optical properties were investigated using UV-vis spectroscopy and the calculated band gap energies are 4.64 and 4.71 eV for pure and doped CuO, respectively. Electrical properties (dielectric constant (</em> ), dielectric loss (tan δ), and AC conductivity (</em> ) were studied using room temperature impedance spectroscopy. Energy dispersive X-ray spectrum of undoped and Ni-doped CuO to confirm the prepared sample composition has also been presented and discussed.</em>

In this work, pure copper oxide and Fe-doped copper oxide nanostructures [Cu1-x FexO where 0 ≤ x ≤ 0.08 in steps of 0.02] were synthesized using the co-precipitation method. Iron nitrate nano-hydrate and copper nitrate trihydrate were used as precursors and NaOH was used as precipitating agent. The samples were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and UV-Visible spectroscopy for their structural, morphological, and optical properties, respectively. The effect of iron concentration on antibacterial activity and hemolysis was also investigated for Escherichia coli and Bacillus Subtilis. The XRD pattern showed a single-phase monoclinic structure of CuO nanoparticles. The average crystallite size of pure copper oxide was found 39 nm whereas the average crystallite size of Fe-doped CuO was found in the range 39-44 nm. It was observed that average crystallite size was increased with an increasing iron concentration in CuO. Scanning electron microscopy analysis showed spherical-like morphology and EDS confirmed the presence of iron and copper with proper composition. UV-vis spectroscopy results showed that the band gap was decreased with increasing iron concentration. Samples prepared with higher concentrations of iron exhibited high E. coli and B. subtilis antibacterial activity. Low hemolytic is safer to be used in various applications such as drug delivery.

In this paper, the spherical CuO/Cu2O nanocomposites were synthesized using co-precipitation accompanied by annealing at 500 and 600 ºC. The as-synthesized CuO/Cu2O nanocomposites were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and transmission electron microscope (TEM). The XRD and FT-IR results predicts the successfully synthesized of CuO/Cu2O nanocomposite. Spherical shapes of samples confirmed by TEM images with narrow particle size distribution. The average size of nanocomposites synthesized at 600 °C (39 nm) is smaller than the nanocomposites synthesized at 500 °C (46 nm). In addition, the samples were chemically activated using H2O2 and used as new adsorbents to remove of Pb(II) ion from aqueous solution. The effect of solution pH, sorbent dose, initial Pb(II) concentration and the contact time were studied and showed that the highest efficiency (85% for nanocomposites synthesized at 500°C and 92% for nanocomposites synthesized at 600 °C) is obtained at pH 6, 90 min contact time, 30 ppm Pb(II) solution and 0.02 g of sorbent. The Pb(II) adsorption equilibrium data are best fitted to the Langmuir model.

The main purpose of this study was to find a simple reaction condition for reproducible synthesis of water-soluble superparamagnetic iron oxide nanoparticles (SPIONs) through the co-precipitation method. For this purpose, the effect of alkali solution, working atmosphere and final reaction temperature on type, size and magnetic properties of synthesized particles were examined. The results reveal that from two different tested alkali precipitants including ammonia and 1M NaOH, samples synthesized using ammonia demonstrate proper magnetic properties, while the latter agent leads to production of nonmagnetic brown suspensions in all reaction conditions. UV-Vis and XRD showed the typical magnetite pattern for samples synthesized using ammonia as the alkali precipitant. In addition, the results show that higher reaction temperatures lead to the production of smaller size black particles with lower oxidation level, better crystallization, and higher saturation magnetization. The optimal results were obtained when the ammonia was used as an alkali precipitant and the reaction temperature was set to 80 ̊C under N2 atmosphere. Furthermore, particles which were made under the air condition at 80 ̊C using 25% ammonia, showed satisfactory dimensional and magnetic properties. The simple reaction condition used in this study could be applicable for large scale synthesis of stable SPIONs.

We prepared samples including nanoparticles of ZnS via co-precipitation method in room temperature and with microwave heating using water as a “green” solvent. The procedure was repeated with various natural surfactants. XRD and SEM analysis was performed to determine the nanostructural and morphologic characteristics of nanoparticles. The mean diameter less than 100 nm for ZnS particles showed that there was well-formed pure nanostructure. SEM analysis disclosed that temperature and type of surfactant will affect the nanostructures and so we can control the nanostructure and particle size with changing such parameters. With combining of pure Carbon and ZnS nanoparticles in various proportions, Carbon - ZnS nanocomposites was prepared using microwave heating. SEM and FT-IR analysis was performed on these nanocomposites to compare them with pure Carbon and ZnS nanoparticles. We also assessed the photocatalytic potential of prepared nanocomposites using acidic and neutral pH methyl orange and Congo red solutions under UV- IR radiation. This study confirms that these nanocomposites can be used as photo-catalysts for water refinery in home and industries.

In this work, a Co-Fe-Ni catalyst was prepared and the effect of a range of operational variables such as gas hourly space velocity (GHSV), calcination temperature, calcination time and agent on its catalytic performance for green-fuels production was investigated. By application of different characterization techniques such as XRD, BET, TGA/DSC, and SEM, it was found that these parameters have great effects on the structure, porosity, morphology and physic-chemical properties of this catalyst. The optimum conditions were found for the samples which were calcined at 550 ℃ in air for 6 hours, and operated at 300 ℃ and 4800h-1 as the reaction temperature and GHSV respectively. Results also revealed that any increase in the calcination temperature promotes the product shifting towards heavier hydrocarbons (more C5+ production). Calcination in air atmosphere was more effective than calcination in N2 atmosphere.

Here in, CeMoO4 nanostructure were successfully prepared by a co-precipitation route without capping agent. The characterization and morphological of as-prepared samples were examined by Fourier transform infrared spectroscopy, filed emission scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. SEM and XRD results show that CeMoO4 nanostructure obtained with average nano-plate thickness 30 nm and average crystal size of 10 nm. The evaluations on CeMoO4-based electrodes revealed the material to have a specific capacitance (SC) of 327 F g-1 at a scan rate of 2 mV s-1, an energy density of 24.5 W h kg-1, and a high rate capability. Continues cyclic voltammetry evaluations using CeMoO4-based electrodes proved the electrodes to be capable of maintaining almost 96.3% of its initial SC after 4000 cycles. To the best of our knowledge, this study is considered as the start point of using lanthanide molybdates as an electrode materials for supercapacitors and the results obviously consent to outstanding properties of CeMoO4 for the mentioned application.

A simple co-presipitation method has been developed to synthesize SrWO4 and Ag°-SrWO4 micro/nanostructures with different morphologies, including platelet-, star- and flower-like, in the presence of Na(B(C6H5)) as surfactant. The formation of platelet-, star- and flower-like shapes of particulate system was examined by electron microscopy technique. The products were characterized by X-ray diffraction, scanning electron microscope, UV-vis absorption, energy dispersive X-ray and fourier transform infrared spectra. The scheelite type tetragonal structure of all the synthesized compounds was revealed by powder X-ray diffraction analysis. The influence of surfactant concentration (sodium tetraphenylborate as new surfactant) on the size and morphology of products was investigated. Finally, a good photocatalytic activity was first discovered of the Ag°-SrWO4 microcrystals for the degradation of methyl orange dye after 100 min under UV-vis light. Hence, from the present investigation it was observed that the doping of Ag in SrWO4 will yield a new kind of multifunctional material for fabricating electronic devices.

Spherical-like hydroxyapatite (HA, Ca10(PO4)6(OH)2) particles were prepared by the co-precipitation method in a simulated physiological environment. The effect of calcining temperature, calcining time and the Ca/P ratio of the initial feeding on the morphology and crystallinity of HA were investigated in detail. Interestingly, while the Ca/P ratio of the initial feeding is 1.80, the obtained HA powders calcined at 800 °C for 2 h contain trace amounts of Na and Mg ions, and the (Ca+Na+Mg)/P ratio is equal to 1.66, which is close to the stoichiometric ratio 1.67 of HA. And a better route with shorter reaction time for the synthesis of HA containing trace amounts of Na and Mg elements was acquired.

FeCe nanoparticles were synthesized by simple co-precipitation method using Iron chloride hexahydrate (FeCl3.6H2O) and cerium chloride (CeCl2•5H2O) as precursors in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The samples were characterized by high resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), vibration sampling magnetometer (VSM), electron dispersive spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) at different temperatures. The XRD results showed that Fe-doped CeO2 was single-phased with a cubic structure. SEM images showed the rod-shaped particles of as-prepared sample in the range size of 40-80 nm and annealed smallest one around 15 nm in diameter at 500oC for 3 h. The TEM studies revealed the squared-like shaped nanosized particles. The sharp peaks in the FTIR spectrum determined the element of Fe-Ce nanoparticles. The EDS spectra showed peaks of iron and cerium with less impurity in the prepared samples. The result of magnetic measurements showed a coercive field and saturated magnetization around 1650 G and 0.04 emu/g for as-prepared samples, respectively.

The presented study investigates application of polyethylene glycol (PEG)-coated Fe3O4 nanoparticles as an magnetic nanoadsorbent for magnetic solid-phase extraction (SPE) and the selective removal of toxic heavy metals such as mercury (II) from aqueous solutions and their determination using graphite furnace atomic absorption spectrometry (GF-AAS). The Fe3O4 magnetic nanoparticles were synthesized using co-precipitation and characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and vibrating-sample magnetometer(VSM). The influences of analytical parameters including pH andeluent type, concentration and volume have been studied and optimized. The optimum pH required for maximum adsorption was found to be 6 for mercury. SEM images showed that the particle- size was about 24 nm and no marked aggregation occurred. XRD indicated the sole existence of inverse cubic spinel phase of Fe3O4 magnetic nanoparticles. VSM patterns indicate superparamagnetic of Fe3O4 magnetic nanoparticles. The results obtained from the recovery test showed the capability and reliability of the method for the removing mercury (II) from wastewater.