scholarly journals Improving stability of cerium oxide nanoparticles by microbial polysaccharides coating

2018 ◽  
Vol 83 (6) ◽  
pp. 745-757 ◽  
Author(s):  
Ivana Milenkovic ◽  
Ksenija Radotic ◽  
Branko Matovic ◽  
Marija Prekajski ◽  
Ljiljana Zivkovic ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Cerium Oxide ◽  
Aqueous Media ◽  
Suspension Stability ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Ft Ir ◽  
Microbial Exopolysaccharides ◽  
The Stability

Cerium oxide (CeO2) nanoparticles (CONPs) are interesting biomaterials with various applications in biomedicine, cosmetics and the pharmaceutical industry, but with limited practical application because of their low stability in aqueous media. The aim of this study was to obtain CONPs with increased stability by coating the particles. Microbial exopolysaccharides (levan, pullulan) and glucose were used to prepare CONPs under different synthesis conditions. Coating was attempted by adding the carbohydrates during (direct coating) or after (subsequent coating) the synthesis of CONPs. The obtained nanoparticles were characterized by X-Ray diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The suspension stability of the uncoated and coated CONPs in aqueous media was evaluated by measuring the hydrodynamic size, zeta potential and turbidity. The FT-IR spectra revealed the differences between coated CONPs and showed the success of subsequent coating with carbohydrates. Coating with carbohydrates improved the stability the CONP suspension by decreasing the size of aggregated particles. The suspensions of levan- and glucose-coated CONPs had the best stability. In this study, CONPs were prepared using non-toxic materials, which were completely environmentally friendly. The obtained results open new horizons for CONP synthesis, improving their biological applications.

scholarly journals Hydrothermal Synthesis, Characterization and Exploration of Photocatalytic Activities of Polyoxometalate: Ni-CoWO4 Nanoparticles

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 456
Author(s):  
Fahad A. Alharthi ◽  
Hamdah S. Alanazi ◽  
Amjad Abdullah Alsyahi ◽  
Naushad Ahmad
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Photocatalytic Reactions ◽  
Cobalt Tungstate

This study demonstrated the hydrothermal synthesis of bimetallic nickel-cobalt tungstate nanostructures, Ni-CoWO4 (NCW-NPs), and their phase structure, morphology, porosity, and optical properties were examined using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman instruments. It was found that as-calcined NCW-NPs have a monoclinic phase with crystal size ~50–60 nm and is mesoporous. It possessed smooth, spherical, and cubic shape microstructures with defined fringe distance (~0.342 nm). The photocatalytic degradation of methylene blue (MB) and rose bengal (RB) dye in the presence of NCW-NPs was evaluated, and about 49.85% of MB in 150 min and 92.28% of RB in 90 min degraded under visible light. In addition, based on the scavenger’s study, the mechanism for photocatalytic reactions is proposed.

Effect of Synthesis Temperature on Particles Size and Morphology of Zirconium Oxide Nanoparticle

2017 ◽  
Vol 50 ◽  
pp. 18-31 ◽  
Author(s):  
Rudzani Sigwadi ◽  
Simon Dhlamini ◽  
Touhami Mokrani ◽  
Patrick Nonjola
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Thermo Gravimetric Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Crystallite Sizes ◽  
Ft Ir

The paper presents the synthesis and investigation of zirconium oxide (ZrO2) nanoparticles that were synthesised by precipitation method with the effects of the temperatures of reaction on the particles size, morphology, crystallite sizes and stability at high temperature. The reaction temperature effect on the particle size, morphology, crystallite sizes and stabilized a higher temperature (tetragonal and cubic) phases was studied. Thermal decomposition, band structure and functional groups were analyzed by Brunauer-Emmett-Teller (BET), Scanning Electron Microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Thermo-gravimetric analysis (TGA) and Fourier transform infrared (FT-IR). The crystal structure was determined using X-ray diffraction. The morphology and the particle size were studied using (SEM) and (TEM). The shaped particles were confirmed through the SEM analysis. The transmission electron microscopic analysis confirmed the formation of the nanoparticles with the particle size. The FT-IR spectra showed the strong presence of ZrO2 nanoparticles.

Study on Nano- and Microcrystallites in Urines of Uric Acid Stone Patients

2013 ◽  
Vol 655-657 ◽  
pp. 1927-1930 ◽  
Author(s):  
Guang Na Zhang ◽  
Zhi Yue Xia ◽  
Jian Ming Ouyang ◽  
Li Kuan
Keyword(s):  
Electron Microscopy ◽  
Uric Acid ◽  
X Ray Diffraction ◽  
Uric Acid Stone ◽  
Urine Ph ◽  
Stone Formers ◽  
Transmission Electron ◽  
Close Relationship ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

The presence of crystallites in urine is closely related to stones formation. In this article, the components, morphology of nano- and micro-crystallites in urines of 20 uric acid (UA) stone formers as well as their relationship with the formation of UAstones were comparatively studied using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The main constituent of urinary crystallites was uric acid. Their particle size distribution was highly uneven, ranging from several nanometers to several tens of micrometers, and obvious aggregation was observed. These results showed that there was close relationship among stone components, urinary crystallites composition and urine pH.

Synthesis of Indole Derivatives Using Biosynthesized ZnO-CaO Nanoparticles as an Efficient Catalyst

2021 ◽  
Vol 66 ◽  
pp. 61-71
Author(s):  
Tahereh Heidarzadeh ◽  
Navabeh Nami ◽  
Daryoush Zareyee
Keyword(s):  
Electron Microscopy ◽  
Indole Derivatives ◽  
X Ray Diffraction ◽  
Efficient Catalyst ◽  
X Ray ◽  
Transmission Electron ◽  
Solvent Free Conditions ◽  
Ft Ir ◽  
Eggshell Waste ◽  
Aromatic And Aliphatic Amines

The principal aim of this research is using biosynthesized ZnO-CaO nanoparticles (NPs) for preparation of indole derivatives. ZnO-CaO NPs have been prepared using Zn(CH3COO)2 and eggshell waste powder in solvent-free conditions. Morphology and structure of NPs were determined by FT-IR, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive spectra (EDS). It was used as a highly efficient catalyst for the synthesis of indole derivatives. Some indole derivatives were synthesized by the reaction of indole, formaldehyde, aromatic and aliphatic amines in the presence of ZnO-CaO NPs (5 mol%) in ethanol under reflux conditions. The assigned structure was further established by CHN analyses, NMR, and FT-IR spectra. Because of excellent capacity, the exceedingly simple workup and good yield, eco-friendly catalyst ZnO-CaO NPs were proved to be a good catalyst for this reaction.

scholarly journals An Efficient and Novel Ammonia Sensor Based on Polypyrrole/Tin Oxide/MWCNT Nanocomposite

2020 ◽  
Vol 32 (6) ◽  
pp. 1505-1510
Author(s):  
Ahmad Husain ◽  
Mohd Urooj Shariq ◽  
Anees Ahmad
Keyword(s):  
Electron Microscopy ◽  
Tin Oxide ◽  
Charge Carriers ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Ammonia Sensing ◽  
Transmission Electron ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

In present study, the synthesis and characterization of a novel polypyrrole (PPy)/tin oxide (SnO2)/MWCNT nanocomposite along with pristine polypyrrole is reported. These materials have been studied for their structural and morphological properties by FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. PPy/SnO2/MWCNT nanocomposite has been converted into a pellet-shaped sensor, and its ammonia sensing studies were carried out by calculating the variation in the DC electrical conductivity at different concentration of ammonia ranging from 10 to 1500 ppm. The sensing response of the sensor was determined at 1500, 1000, 500, 200, 100 and 10 ppm and found to be 70.4, 66.1, 62.2, 55.4, 50.8 and 39.7%, respectively The sensor showed a complete reversibility at lower concentrations along with excellent selectivity and stability. Finally, a sensing mechanism was also proposed involving polarons (charge carriers) of polypyrrole and lone pairs of ammonia molecules

Preparation and characterization emulsion of PANI-TiO2 nanocomposite and its application as anticorrosive coating

2015 ◽  
Vol 35 (6) ◽  
pp. 597-603 ◽  
Author(s):  
Mohsen Khademian ◽  
Hossein Eisazadeh
Keyword(s):  
Electron Microscopy ◽  
Colloidal Particles ◽  
Aqueous Media ◽  
Corrosion Current ◽  
Ammonium Persulfate ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Definition Of

Abstract Emulsion nanoparticles of polyaniline (PANI) were synthesized in the aqueous media by using hydroxylpropylcellulose (HPC) as a stabilizer and ammonium persulfate as an oxidant in the presence of TiO2 with nanometer size. New poly(vinyl acetate) (PVAc) coating over carbon steel was prepared by addition of emulsion nanoparticles in different concentrations (1%, 2% and 1.5%) in PVAc as the major matrix. The Tafel plot records were used for the definition of potential and corrosion current (Icorr). Nanoparticles were characterized and compared by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By adding TiO2, the thermal stability of the nanocomposite increased. A small size of colloidal particles prevented the precipitation of conducting polymer particles and led to better dispersion of nanocomposites in the matrix of the PVAc binder; therefore, the paint was homogeneous and anticorrosion properties of the coating increased. According to the results, 1.5% of PANI-TiO2 nanocomposite in PVAc has a much lower Icorr in NaCl aqueous solution and 2% of PANI-TiO2 nanocomposite in PVAc has the best corrosion protection in HCl.

scholarly journals Influence of different synthesis conditions on properties of oleic acid-coated-Fe3O4 nanoparticles

2015 ◽  
Vol 33 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Atieh Aliakbari ◽  
Majid Seifi ◽  
Sharareh Mirzaee ◽  
Hoda Hekmatara
Keyword(s):  
Oleic Acid ◽  
Room Temperature ◽  
Magnetic Measurement ◽  
Precursor Solution ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Ft Ir

AbstractIn the present paper, iron oxide nanoparticles coated by oleic acid have been synthesized in different conditions by coprecipitation method. For investigating the effect of time spent on adding the oleic acid to the precursor solution, two different processes have been considered. The as synthesized samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). Magnetic measurement was carried out at room temperature using a vibrating sample magnetometer (VSM). The results show that the magnetic nanoparticles decorated with oleic acid decreased the saturation of magnetization. From the data, it can also be concluded that the magnetization of Fe3O4/oleic acid nanoparticles depends on synthesis conditions.

Preparation and application of fluorinated-siloxane protective surface coating material for stone inscriptions

2015 ◽  
Vol 35 (6) ◽  
pp. 511-522 ◽  
Author(s):  
Pengling Li ◽  
Fengxian Qiu ◽  
Xiaoying Zhang ◽  
Lili Wang ◽  
Qian Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Surface Coating ◽  
Coating Material ◽  
Artificial Ageing ◽  
X Ray Diffraction ◽  
Coating Materials ◽  
Ageing Test ◽  
Transmission Electron ◽  
Ft Ir ◽  
Similar Appearance

Abstract A series of fluorinated-siloxane protective surface coating materials (FPA/SiO2) were prepared with different contents of dodecafluoroheptyl methacrylate (DFMA) and fixed content of siloxane. The properties of FPA/SiO2 protective materials were investigated by the methods of Fourier transform infrared spectroscopy (FT-IR) spectra, UV-Vis spectrum, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The surface morphology and mineralogical analysis of the fresh and weathered stone samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The artificial ageing test, which was commonly used as a criterion for the evaluation of the protective ability of FPA/SiO2 coating material, was performed. The results indicate that when the content of DFMA is 30 wt.% and the content of SiO2 is 10 wt.%, the prepared coating material has good comprehensive performances. The artificial ageing test shows that the protective surface coating material has good compatibility with and similar appearance to stone relics. The effect of FPA/SiO2 protective coating material for protection of Jiaoshan Steles Grove (China) is noticeable and it can be widely applied to the protection of stone relics.

Characterization, Optical and Impedance Study of ZnSe Nanostructure

2013 ◽  
Vol 699 ◽  
pp. 490-495
Author(s):  
Ramna Tripathi ◽  
Akhilesh Kumar
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Impedance Spectroscopy ◽  
Zinc Selenide ◽  
Relaxation Times ◽  
Complex Impedance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Stability

Zinc selenide nanoparticle has been synthesized using soft chemical routes. The particles were capped using 2-mercaptoethanol to achieve the stability and avoid the coalescence. The as-obtained particles were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV–VIS absorption and photoluminescence (PL) spectra. The impedance studies were carried out as a function of frequency (100 Hz–1 MHz) and temperature (298–373 K) by impedance spectroscopy. An analysis of the complex impedance (z' and z") with frequency is performed assuming a distribution of relaxation times.

Luminescent properties of Y2O3:Eu3+ nanophosphor prepared from urea added precursor using flame spray pyrolysis

2009 ◽  
Vol 24 (8) ◽  
pp. 2584-2588 ◽  
Author(s):  
Jae Seok Lee ◽  
Se Jin Kim ◽  
Tae Kon Kim ◽  
Rajiv K. Singh ◽  
Madhav B. Ranade
Keyword(s):  
Electron Microscopy ◽  
Spray Pyrolysis ◽  
Red Light ◽  
Luminescent Properties ◽  
Flame Spray Pyrolysis ◽  
Cubic Phase ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Transmission Electron

Y2O3:Eu3+ nanophosphor was synthesized by flame spray pyrolysis (FSP) from urea added nitrate based liquid precursor. In this study, urea serves as fuel and subsequently provides additional heat in the flame zone during the synthesis of phosphor particles. The end product shows cubic phase Y2O3:Eu3+ nanophosphor successfully prepared by FSP without heat treatment. The influence of synthesis conditions such as different mol of urea and nitrate source materials in aqueous solution, and doping concentration on luminescent properties, were investigated. The characteristics of nanophosphor such as crystallinity and morphology under various experiments of conditions were carried out by x-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). The particle size of product was found to be in the range of 20–30 nm from transmission electron microscopy (TEM). In photoluminescence (PL) properties, Y2O3:Eu3+ nanophosphor emitted red light with a peak wavelength of 609 nm when excited with 398 nm wavelength photons.

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