Environmentally Friendly Aqueous Solution Synthesis of Hierarchical CaWO4 Microspheres at Room Temperature

2008 ◽  
Vol 8 (3) ◽  
pp. 1288-1294 ◽  
Author(s):  
Wenshou Wang ◽  
Liang Zhen ◽  
Chengyan Xu ◽  
Baoyou Zhang ◽  
Wenzhu Shao
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Large Scale ◽  
Room Temperature ◽  
Blue Emission ◽  
Environmentally Friendly ◽  
Average Diameter ◽  
Solution Synthesis ◽  
Chemical Route ◽  
Hierarchical Microspheres

An environmentally friendly route for the synthesis of hierarchical CaWO4 microspheres with novel morphology at room temperature has been successfully developed. CaCl2 and Na2WO4 were used as reaction regents, and distilled water was used as an environmentally friendly solvent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy. This green wet-chemical route provides a simple, one-step, low-cost approach for the large-scale synthesis of hierarchical CaWO4 microspheres with relatively uniform diameters of 3–6 μm. The hierarchical microspheres are built up with numerous nanorods with an average diameter of 50 nm, which are radially oriented to the microsphere center. SEM observations of different intermediates indicate the possible growth process, in which the hierarchical structure growth is from nuclei through kayak-like, rod-like, peanut-like, dumbbell-like, and peach-like structures to final microspheres, via "self-assembled preferential end growth" of kayak-like particles in aqueous solution. The hierarchical CaWO4 micro-spheres exhibit a strong, broad blue emission peak of 412 nm.

SYNTHESIS OF CaWO4 AND CaWO4:Eu MICROSPHERES BY PRECIPITATION

NANO ◽  
2014 ◽  
Vol 09 (01) ◽  
pp. 1450008 ◽  
Author(s):  
YUGUO YANG ◽  
XUPING WANG ◽  
BING LIU
Keyword(s):  
Electron Microscopy ◽  
Emission Band ◽  
Large Scale ◽  
Blue Emission ◽  
Average Diameter ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Blue Emission Band ◽  
Transmission Electron ◽  
Cetyltrimethyl Ammonium

Nearly monodisperse CaWO 4 and CaWO 4: Eu 3+ microspheres have been synthesized in large scale by a surfactant-assisted solution route, in which cetyltrimethyl ammonium bromide (CTAB) is used. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) were used to characterize the resulting samples. The results of XRD indicate that the CaWO 4 and CaWO 4: Eu 3+ samples have the scheelite structures. The growth process of these nearly monodisperse spheres with an average diameter around 3.2 μm has been examined. The results of FTIR indicate that CTAB plays an important role in the formation of microspheres. The CaWO 4 microspheres exhibit a blue emission band with a maximum at 423 nm. But the CaWO 4: Eu 3+ microspheres exhibit a red emission band with a maximum at 623 nm.

scholarly journals Synthesis of cobalt nanowires in aqueous solution under an external magnetic field

2016 ◽  
Vol 7 ◽  
pp. 990-994 ◽  
Author(s):  
Xiaoyu Li ◽  
Lijuan Sun ◽  
Hu Wang ◽  
Kenan Xie ◽  
Qin Long ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Aqueous Solution ◽  
External Magnetic Field ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Chemical Reduction ◽  
Average Diameter ◽  
Firm Structure ◽  
Cobalt Nanowires ◽  
First Time

In contrast to the majority of related experiments, which are carried out in organic solvents at high temperatures and pressures, cobalt nanowires were synthesized by chemical reduction in aqueous solution with the assistance of polyvinylpyrrolidone (PVP) as surfactant under moderate conditions for the first time, while an external magnetic field of 40 mT was applied. Uniform linear cobalt nanowires with relatively smooth surfaces and firm structure were obtained and possessed an average diameter of about 100 nm with a coating layer of PVP. By comparison, the external magnetic field and PVP were proven to have a crucial influence on the morphology and the size of the synthesized cobalt nanowires. The prepared cobalt nanowires are crystalline and mainly consist of cobalt as well as a small amount of platinum. Magnetic measurements showed that the resultant cobalt nanowires were ferromagnetic at room temperature. The saturation magnetization (M s) and the coercivity (H c) were 112.00 emu/g and 352.87 Oe, respectively.

scholarly journals Effect of crosslinking with riboflavin and ultraviolet a (UVA) on the scleral tissue structure

2017 ◽  
Vol 10 (2) ◽  
pp. 6-12
Author(s):  
Mukharram M Bikbov ◽  
Valentina K Surkova ◽  
Emin L Usubov ◽  
Nikolaj A Nikitin ◽  
Mikhail Nikolaevich Astrelin
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Average Diameter ◽  
Tissue Structure ◽  
In Vitro Experiments ◽  
Pathological Changes ◽  
Ultraviolet A ◽  
Intermediate Space ◽  
Special Software

Purpose. To evaluate the effect of the scleral crosslinking with riboflavin and ultraviolet A (UVA) on the scleral tissue structure in vitro experiments. Material and methods. The study was conducted on 7 porcine cadaver eyes. Two parallel scleral strips were excised from each eyeball, one of which was subjected to crosslinking procedure (instillation of 0.1% aqueous solution of riboflavin mononucleotide for 20 minutes, ultraviolet irradiation of 3 mW /cm2 for 30 minutes), second was used as control. Scleral structure was evaluated by light (Van Gieson’s stain) and electron microscopy. Morphometric analysis of the microphotographs was performed using special software. Results. As a result of crosslinking, the average packing density of collagen fibers increased by 8.2%, the area of the intermediate space decreased by 5.2%, the average diameter of collagen fibrils increased by 12%. There were no pathological changes in scleral structures. Conclusion. Obtained results confirm the efficacy of scleral crosslinking with riboflavin/UVA in the formation of additional crosslinks, and the procedure safety for the scleral tissue.

scholarly journals Facile and Clean Solution Synthesis of Large-Scale ZnO Nanorods Assisted with Aliquat 336

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qiang Huang ◽  
Jianping Liu
Keyword(s):  
Raman Spectroscopy ◽  
Optical Properties ◽  
Large Scale ◽  
Chemical Method ◽  
Room Temperature ◽  
Zno Nanorods ◽  
Aliquat 336 ◽  
Photoluminescence Spectra ◽  
Solution Synthesis ◽  
Room Temperature Photoluminescence

A facile and clean fabrication of large-scale ZnO nanorods assisted with Aliquat 336 using aqueous chemical method is reported. As prepared, samples were characterized using XRD, EDS, SEM, TEM, and HRTEM. The optical properties were measured by Raman spectroscopy and room temperature photoluminescence spectra.

PHOTOLUMINESCENCE SPECTRA AND MAGNETIC PROPERTIES OF HYDROTHERMALLY SYNTHESIZED MnO2 NANORODS

2013 ◽  
Vol 27 (29) ◽  
pp. 1350211 ◽  
Author(s):  
ARBAB MOHAMMAD TOUFIQ ◽  
FENGPING WANG ◽  
QURAT-UL-AIN JAVED ◽  
QUANSHUI LI ◽  
YAN LI
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Blue Emission ◽  
Green Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Uv Emission ◽  
Transmission Electron

In this paper, single crystalline tetragonal MnO 2 nanorods have been synthesized by a simple hydrothermal method using MnSO 4⋅ H 2 O and Na 2 S 2 O 8 as precursors. The crystalline phase, morphology, particle sizes and component of the as-prepared nanomaterial were characterized by employing X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). The photoluminescence (PL) emission spectrum of MnO 2 nanorods at room temperature exhibited a strong ultraviolet (UV) emission band at 380 nm, a prominent blue emission peak at 453 nm as well as a weak defect related green emission at 553 nm. Magnetization (M) as a function of applied magnetic field (H) curve showed that MnO 2 nanowires exhibited a superparamagnetic behavior at room temperature which shows the promise of synthesized MnO 2 nanorods for applications in ferrofluids and the contrast agents for magnetic resonance imaging. The magnetization versus temperature curve of the as-obtained MnO 2 nanorods shows that the Néel transition temperature is 94 K.

Morphology Controllable Preparation of Gold Nanoplates through an Eco-Friendly Wet-Chemical Route

2014 ◽  
Vol 887-888 ◽  
pp. 108-111
Author(s):  
Zao Yi ◽  
Jiang Shan Luo ◽  
Xi Bo Li ◽  
Yong Yi ◽  
Xi Bin Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Molar Ratio ◽  
Chemical Route ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Wet Chemical Route ◽  
Controllable Preparation

In this paper a simple eco-friendly wet-chemical way was mentioned to synthesize gold nanoplates. The prepared of the gold nanoplates was a seedless process that carried out by mixing HAuCl4 aqueous solution and Tannic acid (TA) solution at room temperature without the other surfactant and capping agents. The scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) have been used to characterize the shape and composition the prepared gold nanoplates. The molar ratio of HAuCl4 and TA can control the shape and the size of gold nanoplates effectively. This research can provide a simple and eco-friendly way for the prepared gold nanoplates in aqueous solution.

scholarly journals Size-Controlled Synthesis of Fe3O4Magnetic Nanoparticles in the Layers of Montmorillonite

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Katayoon Kalantari ◽  
Mansor B. Ahmad ◽  
Kamyar Shameli ◽  
Mohd Zobir Bin Hussein ◽  
Roshanak Khandanlou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Average Diameter ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Interlamellar Space ◽  
Size Controlled ◽  
Chemical Coprecipitation Method

Iron oxide nanoparticles (Fe3O4-NPs) were synthesized using chemical coprecipitation method. Fe3O4-NPs are located in interlamellar space and external surfaces of montmorillonite (MMT) as a solid supported at room temperature. The size of magnetite nanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium. The interlamellar space changed from 1.24 nm to 2.85 nm and average diameter of Fe3O4nanoparticles was from 12.88 nm to 8.24 nm. The synthesized nanoparticles were characterized using some instruments such as transmission electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and Fourier transform infrared spectroscopy.

scholarly journals Preparation and characterization of self-reinforced paper using NaOH/thiourea aqueous solution at room temperature

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8191-8201
Author(s):  
Fuqiang Hu ◽  
Yucheng Hu ◽  
Lingling Zhang ◽  
Meixue Gan ◽  
Shangjun Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Room Temperature ◽  
Paper Strength ◽  
X Ray Diffraction ◽  
Fixed Temperature ◽  
Crystallinity Degree ◽  
X Ray ◽  
Scanning Electron

The aim of this paper was to enhance paper strength in NaOH/thiourea aqueous solution at room temperature. Paper from cotton pulp was saturated with room temperature NaOH/thiourea aqueous solution and placed at a fixed temperature (8, 15, and 20 °C) for a period of time (1 h, 2 h, 4 h, and 6 h). The morphology, X-ray diffraction (XRD), mechanical properties, and density of paper were characterized. The results indicated the paper was self-reinforced. Scanning electron microscopy (SEM) photographs indicated that the structure of the treated papers was increasingly compact with decreasing temperature. The XRD results showed that the crystallinity degree of the paper decreased from 80.0% to 60.0%. The stress at break of the treated papers increased by more than fivefold. The wet tensile strength of the treated papers increased remarkably.

Coprecipitation of barium sulfate and barium carbonate at 80°C

1987 ◽  
Vol 45 ◽  
pp. 352-353
Author(s):  
K. Takiyama
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Barium Sulfate ◽  
Room Temperature ◽  
Barium Carbonate ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Orthorhombic System ◽  
X Ray ◽  
Lattice Constants

The coprecipitation of two sparingly soluble compounds in the aqueous solution has been studied by means of electron microscopy and x-ray diffraction techniques, and the properties of the particles produced by the coprecipitation were discussed as an issue in crystal chemistry. In the present investigation the coprecipitation of barium sulfate and barium carbonate was studied. Both crystals belong to the orthorhombic system. The lattice constants of barium sulfate are ao=8.878, bo=5.450 and co=7.152 Å. Those of barium carbonate are ao=5.314, bo=8.902 and co=6.430 Å. The ratio of the lattice constants of barium sulfate is different from that of barium carbonate. In this investigation, the relation of the morphological properties of the particles with the crystallographic properties of the component compounds was discussed. As the particles became very small when the precipitation was carried out at room temperature, in the present investigation the coprecipitation was done at 80°C to produce larger particles to study the morphological properties of the particles.

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