scholarly journals Enhanced fluorescence of selected cationic dyes adsorbed on reduced-charge montmorillonite

Clay Minerals ◽  
2011 ◽  
Vol 46 (1) ◽  
pp. 93-103 ◽  
Author(s):  
P. Pustková ◽  
Z. Klika ◽  
J. Preclíková ◽  
T. M. Grygar
Keyword(s):  
Methylene Blue ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Nile Blue ◽  
Cationic Dyes ◽  
X Ray Diffraction ◽  
Enhanced Fluorescence ◽  
Visible Absorption ◽  
X Ray ◽  
Diffraction Patterns

AbstractThe aggregation of three cationic dyes (CD), crystal violet (CV), Nile blue (NB) and rhodamine B (RB) in aqueous solution was studied by visible absorption spectrophotometry and compared with methylene blue (MB). The distribution of the dye species (monomers, dimers, trimers, and tetramers) in aqueous solutions with different concentrations of dye was calculated using equilibrium stepwise aggregation constants Kn. These cationic dyes were intercalated into montmorillonite (SAz-1) and its reduced charge form (RC-SAz(210)) prepared by heating lithium montmorillonite (Li/SAz-1) at 210ºC. The fluorescence of fully saturated CD/SAz and low-CD loaded CD/RC-SAz(210) complexes was studied. Visible absorption spectra of CD aqueous solutions and visible absorption spectra and X-ray diffraction patterns (d001) of the CD/SAz and CD/RC-SAz( 210) solid complexes were obtained and evaluated. Large fluorescence intensities were found for CV/RC-SAz(210) and NB/RC-SAz(210) complexes in the same way as for the complex of methylene blue with reduced-charge montmorillonite MB/RCM(210) described previously.

Structural and optical properties of Ba(Co1−xZnx)SiO4 (x = 0.2, 0.4, 0.6, 0.8)

2019 ◽  
Vol 34 (3) ◽  
pp. 242-250 ◽  
Author(s):  
J. Anike ◽  
R. Derbeshi ◽  
W. Wong-Ng ◽  
W. Liu ◽  
D. Windover ◽  
...  
Keyword(s):  
Lattice Parameter ◽  
X Ray Diffraction ◽  
Powder Diffraction File ◽  
Visible Absorption ◽  
X Ray ◽  
Lattice Volume ◽  
Uv Visible ◽  
Diffraction Patterns ◽  
Pattern Determination ◽  
Bright Blue

Structural characterization and X-ray reference powder pattern determination have been conducted for the Co- and Zn-containing tridymite derivatives Ba(Co1−xZnx)SiO4 (x = 0.2, 0.4, 0.6, 0.8). The bright blue series of Ba(Co1−xZnx)SiO4 crystallized in the hexagonal P63 space group (No. 173), with Z = 6. While the lattice parameter “a” decreases from 9.126 (2) Å to 9.10374(6) Å from x = 0.2 to 0.8, the lattice parameter “c” increases from 8.69477(12) Å to 8.72200(10) Å, respectively. Apparently, despite the similarity of ionic sizes of Zn2+ and Co2+, these opposing trends are due to the framework tetrahedral tilting of (ZnCo)O4. The lattice volume, V, remains comparable between 626.27 Å3 and 626.017 (7) Å3 from x = 0 to x = 0.8. UV-visible absorption spectrum measurements indicate the band gap of these two materials to be ≈3.3 and ≈3.5 eV, respectively, therefore potential UV photocatalytic materials. Reference powder X-ray diffraction patterns of these compounds have been submitted to be included in the Powder Diffraction File (PDF).

scholarly journals Ag/AgCl/MIL-101(Fe) Catalyzed Degradation of Methylene Blue under Visible Light Irradation

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1453 ◽  
Author(s):  
Yun Liu ◽  
Yuanhong Xie ◽  
Mingjin Dai ◽  
Qingjiao Gong ◽  
Zhi Dang
Keyword(s):  
Methylene Blue ◽  
Catalytic Activity ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Box Behnken Design ◽  
X Ray ◽  
Plasmonic Material ◽  
Fenton Catalyst ◽  
Diffraction Patterns

A novel photo-Fenton catalyst named Ag/AgCl/MIL-101(Fe) was synthesized by the method of precipitation and photo reduction and characterized by X-ray diffraction patterns (XRD), Brunauer-Emmett-Teller (BET) measurements, Fourier transform infrared spectra (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra. Moreover, the catalytic activity of the synthesized catalyst was tested using methylene blue (MB) as the target pollutant. The obtained results illustrated that the plasmonic material Ag/AgCl was successfully loaded on MIL-101(Fe) and the obtained catalyst exhibited an excellent catalytic activity under visible light at the neutral pH. According to the analyses of Plackett-Burman and Box-Behnken design, the optimum conditions for MB degradation were obtained. Under these conditions, the MB decolorization and mineralization efficiencies could reach to 99.75% and 65.43%, respectively. The recycling experiments also showed that the as-prepared catalyst displayed good reusability. In addition, the possible reaction mechanisms for the heterogeneous photo-Fenton system catalyzed by Ag/AgCl/MIL-101(Fe) were derived. The synthesized catalyst provides a promising approach to degrade organic pollutants in waste water.

Decolorization of Methylene Blue by Photocatalyst in the Ag3PO4-AgI System

2014 ◽  
Vol 970 ◽  
pp. 29-32 ◽  
Author(s):  
Pongsaton Amornpitoksuk ◽  
Sumetha Suwanboon
Keyword(s):  
Methylene Blue ◽  
Mixed Phase ◽  
Photocatalytic Properties ◽  
Precipitation Method ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Co Precipitation

The co-effect of PO43- and I- on the formation of a heterosturucture photocatalyst in the Ag3PO4-AgI system was studied by the co-precipitation method between AgNO3 and the precipitating agent. The precipitating agent was prepared by varying the mole ratios between Na2HPO4 and KI. At 10 mol.% KI, the product showed the mixed phase between Ag3PO4 and un-identified phase. For 30 - 90 mol.% KI, the un-identified phase and AgI were detected in the x-ray diffraction patterns. The un-identified phase strongly adsorbed the methylene blue dye. The product prepared from 30 mol.% KI had the highest content of un-identified phase and also showed the highest degree of decolorization in the dark. The photocatalytic properties of products in this system were confirmed by the decolorization of methylene blue under visible illumination.

Study of Electroluminescence in Cadmium Sulfide Polymer Nanocomposite Films

2017 ◽  
Vol 49 ◽  
pp. 181-189 ◽  
Author(s):  
Vikas Lahariya
Keyword(s):  
Composite Film ◽  
Cadmium Sulfide ◽  
Absorption Spectra ◽  
Polymer Matrix ◽  
Light Emission ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
Zinc Blend ◽  
X Ray ◽  
Uv Visible

Nanocrystalline cadmium sulfide/Polyvinyl alcohol composite films were prepared by chemical route using Cadmium acetate and hydrogen sulfide gas as cadmium and sulfur source respectively. Poly vinyl Alcohal (PVA) used as polymer matrix. The initially loading of cadmium precursor influences the size as well as photoluminescence and electroluminescence properties of the Composite film. The films were characterized by X Ray Diffraction (XRD), Atomic Force Microscopy (AFM) and UV-Visible Absorption spectra. The X-ray Diffraction result showed that CdS nanocrystals embedded in polymer matrix were in a zinc blend cubic structure. The UV-Visible absorption spectra of composite film reveal the blue shift in the band gap energy with respect to CdS bulk (2.42eV) material owing to quantum confinement effect. The Photoluminescence emission spectra show the green light emission at 510 nm arising from the defects states due to excess of cadmium or sulfur anion vacancies. Electroluminescence study indicates enhanced emission with low turn on voltage for higher loading of cadmium in polymer matrix due to increased oscillator strength. When higher electric field is applied, light emission start due to acceleration collision mechanism by charge carries inside the composite film.

The Redistribution of Electrons in La1-xSrxCoO3 Induced by Distortion of CoO6 Octahedron

2013 ◽  
Vol 815 ◽  
pp. 845-853
Author(s):  
Hao Liu ◽  
Hong Guang Zhang ◽  
Yong Tao Li ◽  
Xue Guang Dong ◽  
Yuan Yuan Chen ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Local Structure ◽  
Solid State Reaction Method ◽  
Diffraction Peak ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Types ◽  
Diffraction Patterns ◽  
X Ray Absorption ◽  
Plane Diffraction

The La1-xSrxCoO3(x=0.0, 0.1, 0.2 and 0.3) samples were prepared by solid-state reaction method. The X-ray diffraction patterns show that the samples are ofR-3cspacegroup and the relative intensity of (024) plane diffraction peak increases with the increase of Sr concentration. The x-ray absorption fine structure data of Co ions can be fitted with 2 and 3 different scattering paths for the samples withx=0, 0.1 and forx=0.2 and 0.3, respectively. A new peak arises in x-ray absorption spectra of O ions. These results suggest a relationship between the variations of electron densities and local structure distortion. Both the valence band photoemission and x-ray absorption spectra indicate the existence of possible phase separation scenario that comes from the different types of Co-O bonds which coexist in one sample.

scholarly journals Effect of Molar Ratio on Structural and Size of ZnO/C Nanocomposite Synthesized Using a Colloidal Method at Low Temperature

2019 ◽  
Vol 19 (2) ◽  
pp. 422
Author(s):  
Siham Lhimr ◽  
Saidati Bouhlassa ◽  
Saidati Bouhlassa ◽  
Saidati Bouhlassa ◽  
Bouchaib Ammary ◽  
...  
Keyword(s):  
Room Temperature ◽  
Optical Band Gap ◽  
Hexagonal Wurtzite Structure ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Colloidal Method ◽  
Uv Visible ◽  
Diffraction Patterns

In this paper we study the effects of different molar ratio R of Zn2+ to OH– (R= nOH–/nZn(II) of the precursor was investigated by varying the amount of NaOH. Samples have been synthesized by the colloidal method at room temperature using (ZnCl2), citric acid (C6H8O9·H2O) and sodium hydroxide (NaOH). The formation of ZnO/C composite was characterized by The X-ray diffraction patterns indicated a high crystallinity and nanocrystalline size of ZnO with hexagonal wurtzite structure. The morphologies of the particles have been studied with a scanning electronic microscopy (SEM). The existence of carbon into the composite was detected by FTIR and EDS. The optical band gap of various ZnO/C composite was calculated from UV-Visible absorption measurement varied in the range 3.301 to 3.282 eV according to R values.

Ambient Condition Synthesis of Ag Submicron Crystallites from AgNO3, H2O2 and NH3•H2O

2011 ◽  
Vol 391-392 ◽  
pp. 1392-1395
Author(s):  
Jing Li ◽  
Yong Cai Zhang
Keyword(s):  
Aqueous Solutions ◽  
Atmospheric Pressure ◽  
Cost Effective ◽  
Cubic Phase ◽  
Present System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cost Effective Method ◽  
Diffraction Patterns ◽  
Microscopy Images

A simple and cost-effective method based on the reduction of AgNO3 by H2O2 (5 vol.%) in 2.5–5 vol.% NH3•H2O aqueous solutions at room temperature and under atmospheric pressure was developed for the synthesis of Ag submicron crystallites. X-ray diffraction patterns demonstrated that the resultant products were pure cubic phase Ag powders. Field emission scanning electronic microscopy images showed that the Ag powders synthesized in 2.5 and 5 vol.% NH3•H2O aqueous solutions comprised submicron crystallites with the sizes of about 355–580 and 200–650 nm, respectively. Besides, the possible formation mechanism of Ag powders in the present system was also proposed.

scholarly journals Optical properties for TiO2 / PMMA nanocomposite thin films prepared by plasma jet

2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Titanium Oxide ◽  
Absorption Spectra ◽  
Plasma Jet ◽  
X Ray Diffraction ◽  
Visible Absorption ◽  
X Ray ◽  
Nanocomposite Thin Films ◽  
Uv Visible

PMMA/TiO2 homogeneous thin films were deposited by using plasma jet system under normal atmospheric pressure and room temperature. PMMA/TiO2 nanocomposite thin film synthesized by plasma polymerization. Titanium oxide was mixed with Methyl Methacrylate Monomer (MMA) with specific weight ratios (1, 3 and 5 grams of TiO2 per 100 ml of MMA). Optical properties of PMMA/TiO2 nanocomposite thin films were characterized by UV-Visible absorption spectra using a double beam UV-Vis-NIR Spectrophotometer. The thin films surface morphological analysis is carried out by employing SEM. The structure analysis are achieved by X-ray diffraction. UV-Visible absorption spectra shows that the increasing the concentration of titanium oxide added to the polymer leads to shift the peak position (λmax) toward the infrared region of the electromagnetic spectrum. Also the peak width increases when the concentration of TiO2 increases. It can be controlled optical energy band gap of PMMA/TiO2 nanocomposite thin films by changing concentration of TiO2. SEM indicate a uniform distribution of titanium oxide particles in PMMA matrix. The x-ray diffraction pattern indicated that the thin films have amorphous structure.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

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