Reaction products of organic dye molecules with acid-treated montmorillonite

Clay Minerals ◽  
1983 ◽  
Vol 18 (4) ◽  
pp. 447-458 ◽  
Author(s):  
R. Fahn ◽  
K. Fenderl
Keyword(s):  
Electron Microscopy ◽  
Amorphous Silica ◽  
Acid Treatment ◽  
Organic Dye ◽  
Dye Molecules ◽  
Reaction Products ◽  
Acid Attack ◽  
Colour Intensity ◽  
Transmission Electron ◽  
Octahedral Cations

AbstractDuring the reaction of solutions of the leuco dyes crystal violet lactone and N-benzoyl leuco methylene blue with acid-treated montmarillonite (as occurs with carbonless copying papers), most of the offered dye is intercalated within the interlayers of the montmorillonite structure remaining after acid attack. This phenomenon was demonstrated by XRD and also by high-resolution transmission electron microscopy. During acid treatment, octahedral cations are dissolved from exposed edges of the montmorillonite lamellae and amorphous silica builds up in these areas. As a result, the BET(N2) specific surface area increases from ∼60 m2/g to ∼300 m2/g and, consequently, the theoretical reactivity towards leuco dyes. Nevertheless, only small quantities of the dye molecules are adsorbed onto the amorphous silica. The excellent colour intensity and, in particular, the resistance to fading in the light of the montmorillonite dye complexes may be explained by the protected position of the dye molecules within the interlayers of the montmorillonite.

Microtexture of shock reaction products of niobium and silica mixtures

1999 ◽  
Vol 14 (7) ◽  
pp. 3169-3174 ◽  
Author(s):  
Reiko Murao ◽  
Masae Kikuchi ◽  
Kiyoto Fukuoka ◽  
Eiji Aoyagi ◽  
Toshiyuki Atou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Shock Compression ◽  
Pressure Range ◽  
Reaction Products ◽  
Small Particles ◽  
Powder Mixtures ◽  
X Ray ◽  
Transmission Electron

Shock compression experiments on powder mixtures of niobium metal and quartz were conducted for the pressure range of 30–40 GPa by a 25-mm single-stage propellant gun. Chemical reaction occurred above 35 GPa, and products were found to be mainly so-called “Cu3Au-type” Nb3Si, which contained a small amount of oxygen. Microtextures of the specimen were examined by scanning and transmission electron microscopy. A field-emission transmission electron microscope was used for energy-dispersive x-ray analysis of microtextures in small particles found in the SiO2 matrix, and various species with different Nb/Si ratio and oxygen content were shown to be produced through the nonequilibrium process of shock compression.

Electron microscopy study of interfacial structure and reaction of Yba2Cu3O7/Y-ZrO2 films on LaAlO3 substrates

1998 ◽  
Vol 13 (6) ◽  
pp. 1485-1491 ◽  
Author(s):  
J. Y. Dai ◽  
F. H. Kaatz ◽  
P. R. Markworth ◽  
D. B. Buchholz ◽  
X. Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Interfacial Reaction ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Interfacial Structure ◽  
Reaction Products ◽  
Transmission Electron

The detailed structure and interfacial reaction of epitaxial Yba2Cu3O7/Y-ZrO2 (YBCO/YSZ) films grown by chemical vapor deposition (CVD) on LaAlO3 (LAO) substrates are investigated by means of high-resolution electron microscopy (HREM), analytical transmission electron microscopy, and scanning transmission electron microscopy (STEM). The epitaxial relations of YBCO/YSZ/LAO are [100]YBCO // [110]YSZ // [100]LAO and (001)YBCO // (001)YSZ // (001)LAO. The optimum atomic configuration at the YSZ/LAO interface, in which oxygen is the first atomic layer on LAO, is proposed by using HREM combined with image simulation based on the atomic structure models of the interface. Near the YBCO/YSZ interface, two localized interfacial reaction products are formed: (i) a Y-rich modulated ZrO2 structure at the surface of the YSZ film, which may be caused by the diffusion of Y into the YSZ grains; (ii) an intergranular BaZrO3 phase formed by the diffusion of Ba along the columnar grain boundaries of the YSZ film during YBCO growth.

scholarly journals The Formation Mechanism of a Self-Organized Periodic-Layered Structure at the Solid-(Cr, Fe)2B/Liquid-Al Interface

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3869
Author(s):  
Mengmeng Wang ◽  
Jiang Ju ◽  
Jingjing Li ◽  
Yang Zhou ◽  
Haiyang Lv ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Formation Mechanism ◽  
Layered Structure ◽  
Electron Backscatter Diffraction ◽  
Reaction Products ◽  
Phase Layer ◽  
Transmission Electron ◽  
Potential Formation ◽  
Backscatter Diffraction ◽  
Periodic Layered Structure

A periodic-layered structure was observed in solid-(Cr, Fe)2B/liquid-Al diffusion couple at 750 °C. The interface morphology, the reaction products, and the potential formation mechanism of this periodic-layered structure were investigated using an electron probe microanalyzer (EPMA), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and energy-dispersive spectroscopy (EDS). The results indicate that the reaction between (Cr, Fe)2B and liquid Al is a diffusion-controlled process. The formation of intermetallics involves both the superficial dissolution of Fe and Cr atoms and the inward diffusion of Al at the interface. The layered structure, as characterized by various experimental techniques, is alternated by a single FeAl3 layer and a (FeAl3 + Cr3AlB4) dual-phase layer. A potential mechanism describing the formation process of this periodic-layered structure was proposed based on the diffusion kinetics based on the experimental results.

Detection of Amorphous Silica in Air-Oxidized Ti3SiC2 at 500–1000°C by NMR and SIMS

2010 ◽  
Vol 434-435 ◽  
pp. 169-172 ◽  
Author(s):  
Wei Kong Pang ◽  
It Meng Low ◽  
J.V. Hanna
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Transmission Electron Microscopy ◽  
Amorphous Silica ◽  
Direct Evidence ◽  
Secondary Ion Mass Spectrometry ◽  
Amorphous Sio2 ◽  
Transmission Electron ◽  
First Time ◽  
Secondary Ion

The use of secondary-ion mass spectrometry (SIMS), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti3SiC2 oxidised at 500–1000°C is described. The formation of an amorphous SiO2 layer and its growth in thickness with temperature was monitored using dynamic SIMS. Results of NMR and TEM verify for the first time the direct evidence of amorphous silica formation during the oxidation of Ti3SiC2 at 1000°C.

scholarly journals A novel and facile method for silica nanoparticles synthesis from high temperature vulcanization (HTV) silicon

10.30544/134 ◽  
2016 ◽  
Vol 22 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Mohammad Senemar ◽  
Ali Maleki ◽  
Behzad Niroumand ◽  
Alireza Allafchian
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Silica Nanoparticles ◽  
Amorphous Silica ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Nanoparticles Synthesis ◽  
Novel Method ◽  
Scanning Electron

This study is introducing a facile and novel method for synthesis of amorphous silica nanoparticles. Silica nanoparticles were synthesized by pyrolysis and combustion of high temperature vulcanization (HTV) silicone at 700 oC for 1 h. The products were investigated employing transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD), Brunauer Emmett and Teller (BET) test and Fourier Transform Infrared (FTIR) Spectroscopy. The results indicated that the method is capable of synthesis of amorphous silica nanoparticles with sizes of mostly between 10 and 50 nm.

scholarly journals Green Synthesis of High Temperature Stable Anatase Titanium Dioxide Nanoparticles Using Gum Kondagogu: Characterization and Solar Driven Photocatalytic Degradation of Organic Dye

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1002 ◽  
Author(s):  
Kothaplamoottil Sivan Saranya ◽  
Vinod Vellora Thekkae Padil ◽  
Chandra Senan ◽  
Rajendra Pilankatta ◽  
Kunjumon Saranya ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Green Synthesis ◽  
Organic Dye ◽  
Bet Surface Area ◽  
Tio2 Nps ◽  
X Ray ◽  
Transmission Electron

The present study reports a green and sustainable method for the synthesis of titanium dioxide (TiO2) nanoparticles (NPs) from titanium oxysulfate solution using Kondagogu gum (Cochlospermum gossypium), a carbohydrate polymer, as the NPs formation agent. The synthesized TiO2 NPs were categorized by techniques such as X-Ray Diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy analysis, Raman spectroscopy, scanning electron microscope- Energy-dispersive X-ray spectroscopy (SEM-EDX), Transmission electron microscopy (TEM), High-resolution transmission electron microscopy (HR-TEM), UV-visible spectroscopy, Brunauer-Emmett-Teller (BET) surface area and particle size analysis. Additionally, the photocatalytic actions of TiO2 NPs were assessed with regard to their ability to degrade an organic dye (methylene blue) from aqueous solution in the presence of solar light. Various parameters affecting the photocatalytic activity of the TiO2 NPs were examined, including catalyst loading, reaction time, pH value and calcination temperature of the aforementioned particles. This green synthesis method involving TiO2 NPs explores the advantages of inexpensive and non-toxic precursors, the TiO2 NPs themselves exhibiting excellent photocatalytic activity against dye molecules.

Transmission electron microscopy of pyrometamorphic breakdown of phengite and chlorite

1987 ◽  
Vol 51 (359) ◽  
pp. 107-121 ◽  
Author(s):  
R. H. Worden ◽  
P. E. Champness ◽  
G. T. R. Droop
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microprobe Analysis ◽  
Chemical Interaction ◽  
Reaction Products ◽  
Orientation Relationships ◽  
Fine Grained ◽  
Transmission Electron ◽  
Significant Chemical ◽  
Diagram Analysis

AbstractPhengite and chlorite have undergone decomposition during pyrometamorphism caused by the intrusion of a dolerite feeder pipe into Dalradian greenschists in Argyllshire, Scotland. All reaction products are extremely fine grained. Transmission electron microscopy has revealed that phengite pseudomorphs consist of biotite, spinel, mullite, sanidine and phengite, and that chlorite pseudomorphs consist of combinations of chlorite, spinel, orthopyroxene, magnetite, cordierite and biotite. Although the reactions were short-lived and did not go to completion, microprobe analysis and phase diagram analysis have revealed that there has been significant chemical interaction between the phyllosilicates and the surrounding rock. Numerous orientation relationships exist between the original minerals and their reaction products; the close-packed planes in the precursor phyllosilicates were inherited by their reaction products.

Kinetic controls on the formation of metastable phases during the experimentally induced breakdown of chlorite

1993 ◽  
Vol 57 (386) ◽  
pp. 141-156 ◽  
Author(s):  
K. A. Waldron ◽  
G. T. R. Droop ◽  
P. E. Champness
Keyword(s):  
Electron Microscopy ◽  
Grain Boundaries ◽  
Reaction Mechanisms ◽  
Experimental Studies ◽  
Contact Metamorphism ◽  
Reaction Products ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
Chlorite Schist

AbstractThe kinetics and reaction mechanisms of chlorite breakdown have been studied in a series of experiments at conditions similar to those achieved during contact metamorphism (T = 600-725°C P = 1 kbar). Cores of chlorite schist were used as starting material in order to simulate natural metamorphic systems and preserve reaction textures. Reaction products were analysed by electron microprobe, scanning- and transmission-electron microscopy (SEM, TEM). Although the texture of the original chlorite was preserved in experiments run below 680°C talc had replaced chlorite. Olivine and spinel formed along grain boundaries, indicating long-range diffusion of aluminium. Above 680°C the chlorite was replaced by patches of disordered, aluminous pyroxene. Olivine and spinel grew both within the pyroxene and along what are believed to be former chlorite grain-boundaries. Reactions relevant to the observed textures and assemblages are:Thermodynamic calculations show that both of these reactions are metastable in the FeO-MgO-Al2O3-SiO2-H2O system in the P-T range of our experiments. In addition, previous experimental studies and our calculations indicate that the stable reaction is:The absence of cordierite in the run products, and the formation of talc and orthopyroxene while thermodynamically metastable, show that the ease of nucleation of these phases controlled the reaction mechanisms in the early stages.

Determination of reversible hydrogen adsorption site in Ni-nanoparticle-dispersed amorphous silica for hydrogenseparation at high temperature

2010 ◽  
Vol 25 (10) ◽  
pp. 2008-2014 ◽  
Author(s):  
Yumi H. Ikuhara ◽  
Tomohiro Saito ◽  
Yukichi Sasaki ◽  
Seiji Takahashi ◽  
Tsukasa Hirayama
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Area ◽  
Amorphous Silica ◽  
Hydrogen Adsorption ◽  
Total Surface Area ◽  
Dark Field ◽  
Adsorbed Hydrogen ◽  
Ni Nanoparticles ◽  
Transmission Electron

The reversible hydrogen adsorption site in Ni-nanoparticle-dispersed amorphous silica (Si-O) was identified by analyzing the hydrogen adsorption behavior and the microstructure. The total amount of reversibly adsorbed hydrogen was evaluated from the total surface area of Ni and the Ni concentration in the composite. The total surface area of the Ni nanoparticles in each sample powder was calculated from the mean particle size of the Ni nanoparticles in the Si-O matrix using dark field images taken by transmission electron microscopy and high-angle annular dark-field images by scanning transmission electron microscopy. The estimated amount of reversibly adsorbed hydrogen was highly consistent with that obtained experimentally by hydrogen adsorption analysis, which suggested that reversible hydrogen adsorption occurred at the Ni/Si-O interface.

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