scholarly journals Silane coupling and mordanting as attachment techniques for pyridylazo and thiazolylazo ligands in the synthesis of adsorbents for uranium in seawater

2018 ◽  
Vol 36 (3-4) ◽  
pp. 1144-1159
Author(s):  
Grace M Pooley ◽  
Mohammad A Adel-Hadadi ◽  
Weixing Li ◽  
Travis C Dietz ◽  
Aaron Barkatt
Keyword(s):  
Cellulose Fibers ◽  
Azo Compounds ◽  
Carbon Adsorbents ◽  
X Ray ◽  
Silica Fibers ◽  
Silane Coupling ◽  
High Concentrations ◽  
Derivatives Of ◽  
Aluminum Acetate ◽  
Scanning Electron

Activated carbon adsorbents modified with azo compounds (4-(2-pyridylazo)resorcinol, 1-(2-pyridylazo)-2-naphthol, 4-(2-thiazolylazo)resorcinol), or with allyl and vinylbenzyl derivatives of 4-(2-thiazolylazo)resorcinol, were observed to be highly effective in removing uranium from seawater and providing high loadings. Adsorbents consisting of azo compounds attached to fiber fabrics were prepared using silane coupling to attach azo reagents to silica fibers or mordanting agents such as tannic acid or aluminum acetate to attach them to cellulose fibers. Loadings of 15–45 mg U g−1 adsorbent were obtained. Scanning electron microscopy/energy dispersive X-ray spectroscopy measurements confirmed the presence of high concentrations of uranium on the surface of the silica-based and cellulose-based fibers.

scholarly journals Structural and Optical Investigations of Heterostructures Based on AlxGa1-xAsyP1-y:Si Solid Solutions Obtained by MOCVD

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
P. V. Seredin
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Epitaxial Films ◽  
X Ray Diffraction ◽  
Energy Characteristics ◽  
X Ray ◽  
Epitaxial Heterostructures ◽  
High Concentrations ◽  
Scanning Electron

We investigated MOCVD epitaxial heterostructures based on AlxGa1−xAs ternary solid solutions, obtained in the range of compositions x~0.20–0.50 and doped with high concentrations of phosphorus and silicon atoms. Using the methods of high-resolution X-ray diffraction, scanning electron microscopy, X-ray microanalysis, Raman spectroscopy, and photoluminescence spectroscopy we have shown that grown epitaxial films represent five-component (AlxGa1−xAs1−yPy)1−zSiz solid solutions. The implementation of silicon in solid solution with a concentration of ~ 0.01 at.% leads to the formation of the structure with deep levels, DX centers, the occurrence of which fundamentally affects the energy characteristics of received materials.

Preparation and Surface Modification of Fe3O4@Sio2 Composite Microspheres

2012 ◽  
Vol 455-456 ◽  
pp. 115-120
Author(s):  
Kui Zhou ◽  
Ming Yang ◽  
Qian Sun ◽  
Zhi Zuo Yang
Keyword(s):  
Fourier Transform ◽  
Silane Coupling Agent ◽  
Magnetic Particles ◽  
Composite Particles ◽  
Magnetic Response ◽  
X Ray ◽  
Composite Microspheres ◽  
Silane Coupling ◽  
Magnetic Fe3o4 ◽  
Scanning Electron

Magnetic Fe3O4@SiO2 composite microspheres were prepared using hydrolyzation of tetraethoxysilane and Fe3O4 nanoparticles as seeds, and then the resultant composite particles were modified with silane coupling agent 3-methacryloxypropyltrimethoxy silane. The products were characterized by scanning electron microscope, X-ray powder diffraction, fourier transform infrared spectroscopy, and vibrating-sanple magnetometry, respectively. The results clearly show that the magnetic particles have favorable superparamagnetism and remain strong magnetic response. Moreover, the duplex bonds of carbon functional groups from 3-methacryloxypropyltrimethoxy silane was introduced onto the suface of Fe3O4@SiO2 composite particles.

scholarly journals Influence of Strong Acid Hydrolysis Processing on the Thermal Stability and Crystallinity of Cellulose Isolated from Wheat Straw

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Chemar J. Huntley ◽  
Kristy D. Crews ◽  
Mohamed A. Abdalla ◽  
Albert E. Russell ◽  
Michael L. Curry
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Scanning Electron Microscopy ◽  
Acid Hydrolysis ◽  
Wheat Straw ◽  
Cellulose Fibers ◽  
Drying Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Cellulose extractions from wheat straw via hydrochloric, nitric, and sulfuric acid hydrolysis methods were carried out. X-ray diffraction spectral analyses reveal that depending on the acid conditions used the structure of the cellulose exhibited a mixture of polymorphs (i.e., CI and CIII cellulose phases). In addition, the percent crystallinity, diameter, and length of the cellulose fibers varied tremendously as determined by X-ray diffraction and scanning electron microscopy. Thermal gravimetric analysis measurements revealed that the thermal stability of the extracted cellulose varied as a function of the acid strength and conditions used. Scanning electron microscopy analysis revealed that the aggregation of cellulose fibers during the drying process is strongly dependent upon the drying process and strength of the acids used.

Synthesis of MoO3 Nanostructures by a Solution Method

2012 ◽  
Vol 554-556 ◽  
pp. 494-497
Author(s):  
Kai Du ◽  
Rong Hui Wei ◽  
Ya Nan Bai ◽  
Yadi Gu ◽  
Li Ben Li
Keyword(s):  
Silane Coupling Agent ◽  
Solution Method ◽  
Orthorhombic Phase ◽  
Ammonium Molybdate ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Transmission Electron ◽  
Silane Coupling ◽  
Scanning Electron

Synthesis and characterization of microsheets, microrods, microflowers and microspheres of orthorhombic phase molybdenum oxide (MoO3) were reported. The reaction between ammonium molybdate and hydrochloric acid was used to prepare MoO3microstructures and followed by annealing in air at 400oCfor 2h. The combined techniques of X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy were used to investigate the effect of pH and additives on the as-prepared samples. Results indicated that they were of microsize. With alcohol as an additive, the sample was plate-like MoO3at pH=2.5, and it was a mixture of MoO3and MoO3•0.55H2O of irradiative corolla at pH=1. The sample obtained by hydrothermal was MoO3flowers. Meanwhile, when silane coupling agent was introduced as the additive, the sample was MoO3spheres.

A Malpighian Tubule Lime Gland in an Insect Inhabiting Alkaline Salt Lakes

1989 ◽  
Vol 145 (1) ◽  
pp. 63-78 ◽  
Author(s):  
DAVID B. HERBST ◽  
TIMOTHY J. BRADLEY
Keyword(s):  
Malpighian Tubule ◽  
Cell Types ◽  
Chemical Precipitation ◽  
Malpighian Tubules ◽  
Salt Lakes ◽  
Alkaline Salt ◽  
X Ray ◽  
Posterior Pair ◽  
High Concentrations ◽  
Scanning Electron

The alkali fly, Ephydra hians Say, inhabits alkaline salt lakes which can contain concentrations of dissolved carbonate and bicarbonate as high as 500 mmol l−1. Larvae of the alkali fly possess two pairs of Malpighian tubules. The posterior pair has a morphology similar to that of the tubules of most other insects, but the anterior pair is modified into an enlarged gland containing white microsphere concretions. We describe the ultrastructure of all cell types in both pairs of tubules. Using scanning electron microscope (SEM) X-ray microanalysis and chemical CO2 quantification, we demonstrate that the concretions in the lime glands are composed of nearly pure calcium carbonate. Isolated preparations of lime gland tubules accumulate 45Ca significantly more rapidly than do normal tubules. Although similar to the rime concretions found in the Malpighian tubules of other Diptera, the lime glands of this insect may function to regulate the high concentrations of carbonate and bicarbonate encountered in their aquatic environment. It is proposed that the mechanism of this regulation may be chemical precipitation of carbonate/bicarbonate with calcium in the lumen of these specialized lime gland tubules.

Al-Doped ZnO Nanoparticles Synthesized by Sonochemical-Assisted Method

2013 ◽  
Vol 770 ◽  
pp. 354-357
Author(s):  
Krisana Chongsri ◽  
N. Wongpisutpaisan ◽  
A. Sungthong ◽  
Naratip Vittayakorn ◽  
Wisanu Pecharapa
Keyword(s):  
Electron Microscope ◽  
Calcination Temperature ◽  
Zno Nanoparticles ◽  
Sonochemical Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doped Zno ◽  
Surface Morphologies ◽  
Aluminum Acetate ◽  
Scanning Electron

Al-doped ZnO nanoparticles were synthesized by sonochemical method from zinc acetate dehydrate and aluminum acetate as starting precursors. The deionized (DI) water was selected as the solvent. Sonication of the precursor was performed by a Sonics Model VCX 750 for 30 minutes until precipitated product was finally obtained. The as-precipitated powders were calcined at different temperature range of 550-1100 °C for 2 hr. For all samples, their crystal structures were investigated by X-ray diffraction (XRD) and surface morphologies were observed by scanning electron microscope (SEM). The XRD results revealed that, the purity of as-synthesized powders increases when the calcination temperature increases. Moreover, it is noticed that the AlZnO partial peaks will appear when the as-synthesized powders were calcined at 800 – 1000 °C. In addition, SEM micrographs show the increase of agglomeration and the particles when the calcination temperature increases.

scholarly journals Comparative Study of Carbon Nanosphere and Carbon Nanopowder on Viscosity and Thermal Conductivity of Nanofluids

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 608
Author(s):  
Thong Le Ba ◽  
Marcell Bohus ◽  
István Endre Lukács ◽  
Somchai Wongwises ◽  
Gyula Gróf ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Fourier Transform ◽  
Photoelectron Spectroscopy ◽  
Comparative Research ◽  
Base Fluid ◽  
X Ray ◽  
Ft Ir ◽  
High Concentrations ◽  
Scanning Electron

A comparative research on stability, viscosity (µ), and thermal conductivity (k) of carbon nanosphere (CNS) and carbon nanopowder (CNP) nanofluids was performed. CNS was synthesized by the hydrothermal method, while CNP was provided by the manufacturer. Stable nanofluids at high concentrations 0.5, 1.0, and 1.5 vol% were prepared successfully. The properties of CNS and CNP nanoparticles were analyzed with Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), specific surface area (SBET), X-ray powder diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA), and energy dispersive X-ray analysis (EDX). The CNP nanofluids have the highest k enhancement of 10.61% for 1.5 vol% concentration compared to the base fluid, while the CNS does not make the thermal conductivity of nanofluids (knf) significantly higher. The studied nanofluids were Newtonian. The relative µ of CNS and CNP nanofluids was 1.04 and 1.07 at 0.5 vol% concentration and 30 °C. These results can be explained by the different sizes and crystallinity of the used nanoparticles.

Effect of MgO and NH4OH on Formation of 5Mg(OH)2·MgSO4·3H2O Whiskers

2012 ◽  
Vol 512-515 ◽  
pp. 91-94 ◽  
Author(s):  
Ri Yu ◽  
Jae Hwan Pee ◽  
Hyung Tae Kim ◽  
Kyung Ja Kim ◽  
Young Woong Kim ◽  
...  
Keyword(s):  
Molar Ratio ◽  
X Ray Diffraction ◽  
High Quality ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Practical Applications ◽  
Thermo Gravimetric Analyzer ◽  
High Concentrations ◽  
Sulfate Hydrate ◽  
Scanning Electron

The Magnesium hydroxide sulfate hydrate whiskers (5Mg(OH)2.MgSO4.3H2O, abbreviated 513MHSH) have attracted much attention due to its practical applications as filler and reinforcement. However, it is difficult to produce high quality MHSH because plate-like Mg(OH)2 impurities were formed in high concentrations of OH- and interaction between Mg2+ and OH-. In this work, to reduce formation Mg(OH)2, molar ratio ofSuperscript text magnesium oxide (MgO) and magnesium sulfate (MgSO4.7H2O) were controlled. As a result, when low concentration of SO42-, MHSH whiskers co-existed with hexagonal plate Mg(OH)2. The molar ratio of MgSO4.7H2O/MgO was high, uniform MHSH whiskers were formed without Mg(OH)2. In addition, appropriate amount of NH4OH has affected formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA)

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

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