scholarly journals Barium-Encapsulated Biodegradable Polycaprolactone for Sulfate Removal

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1789
Author(s):  
Changseok Han ◽  
Mallikarjuna Nadagouda
Keyword(s):  
Electron Microscopy ◽  
Barium Carbonate ◽  
High Capacity ◽  
Small Scale ◽  
Ohio River ◽  
Sulfate Removal ◽  
Transmission Electron ◽  
Before And After ◽  
High Resolution Tem ◽  
The Media

Various compositions of barium carbonate (BaCO3) loaded polycaprolactone (PCL) composites were prepared, including 2.5/97.5, 10/90, 30/70, 50/50 and 90/10 (PCL/BaCO3), via re-precipitation technique. Small-scale column tests were conducted to study the efficiency of sulfate removal using the PCL/BaCO3 composites. The composites before and after their use to remove sulfate were extensively characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and thermogravimetric analysis (TGA). As PCL is a biodegradable polymer, these composites are environmentally friendly and have several advantages over barium sulfate precipitation in overcoming clogging issues in filters or resins due to collection of natural organic matter (NOM). The media used in this study exhibited high capacity and was able to remove more than 90% sulfate from synthetic sulfate containing waters and NOM samples collected from the Ohio River.

Synthesis of calcium carbonate capsules in water-in-oil-in-water double emulsions

2008 ◽  
Vol 23 (1) ◽  
pp. 140-149 ◽  
Author(s):  
G.X. Wu ◽  
J. Ding ◽  
J.M. Xue
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
High Capacity ◽  
Hollow Structure ◽  
Double Emulsion ◽  
Guest Molecules ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Size Uniformity ◽  
Capsule Size

Hollow capsules have been intensively investigated due to their high capacity of encapsulating large quantities of guest molecules, making them promising candidate materials for various encapsulation applications. In this work, CaCO3 hollow capsules were successfully synthesized via an emulsion route. The interior hollow structure of the capsules was confirmed by using scanning electron microscopy and transmission electron microscopy (TEM). The vaterite polymorph of the as-synthesized CaCO3 capsules was determined by using x-ray diffraction, high-resolution TEM, and Fourier transform infrared spectroscopy. A self-assembly model was proposed to explain the formation mechanism of the vaterite capsules. By adjusting experimental parameters such as the internal solution amount and the surfactant amount of the double-emulsion system, the average capsule size could be adjusted accordingly. However, the increase in capsule size was at a compensation of size-uniformity degradation. The capsule size uniformity was then further optimized by increasing the magnetic stirring rate. The resultant vaterite capsules demonstrated biodegradability behavior after immersion in phosphate-buffered saline solution, leading to their promising applications in the area of controlled drug delivery.

Structure of Shear Bands in Zirconium-Based Metallic Glasses Observed by Transmission Electron Microscopy

2002 ◽  
Vol 754 ◽  
Author(s):  
Xiaofeng Gu ◽  
Kenneth J. T. Livi ◽  
Todd C. Hufnagel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Metallic Glasses ◽  
Defect Structure ◽  
Shear Bands ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Before And After ◽  
High Resolution Tem ◽  
Band Spacing

ABSTRACTWe have used transmission electron microscopy (TEM) to investigate the structure of shear bands produced by bending electron-transparent Zr52.5Cu17.9Ni14.6Al10Ti5 metallic glass specimens. Shear bands were located by comparing the structure of the specimens before and after deformation. The shear band spacing is influenced by the structure of the specimen; portions of the specimen with a significant population of nanocrystals show a smaller separation between shear bands. Quantitative high resolution TEM analysis based on ratio technique has been used to explore the defect structure in shear bands. High density and void-like defects with size of about 1 nm were found in shear bands formed in both amorphous and nanocrystalline areas. A simple model was proposed to explain the formation of these defects.

Characterization of BN Rich Layer on Ammonia Treated Nextel™312 Fibers

1994 ◽  
Vol 365 ◽  
Author(s):  
N.R. Khasgiwale ◽  
E.P. Butler ◽  
L. Tsakalakos ◽  
D.A. Hensley ◽  
W.R. Cannon ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Layer Thickness ◽  
Photoelectron Spectroscopy ◽  
Fiber Surface ◽  
Ammonia Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Before And After ◽  
High Resolution Tem

ABSTRACTA BN rich layer grown on Nextel™312 fibers by appropriate ammonia treatments was evaluated using various complimentary techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM)/ Parallel Electron Energy Loss Spectroscopy (PEELS in TEM). Three different ammonia treatments were studied. Ammonia treatment resulted in crystallization of the Nextel™312 fiber. The BN rich surface layer formed due to ammonia treatment was clearly detected in XPS and PEELS both before and after oxidation. The layer thickness was estimated to be between 5–10 nm. The layer was stable after oxidation treatment at 600°C for 100 hours. High resolution TEM observations of the fiber surface revealed a variable BN rich layer thickness. Patches of turbostratic BN were observed under certain conditions, however mostly the layer appeared to be amorphous.

A novel additive-free oxides–hydrothermal approach for monazite-type LaPO4nanomaterials with controllable morphologies

2010 ◽  
Vol 43 (5) ◽  
pp. 990-997 ◽  
Author(s):  
Jie Ma ◽  
Qingsheng Wu
Keyword(s):  
Electron Microscopy ◽  
Treatment Time ◽  
Synthesis Temperature ◽  
Molar Ratio ◽  
Hydrothermal Conditions ◽  
Typical Sample ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Hydrothermal Approach

A facile oxides–hydrothermal (O–HT) method is demonstrated to prepare high-purity monazite-type LaPO4nanomaterials. In this approach, La2O3and P2O5powder are first directly used as precursors under additive-free hydrothermal conditions. The as-prepared samples are characterized with X-ray diffraction, Fourier transform IR spectroscopy, thermogravimetry, scanning electron microscopy, transmission electron microscopy (high-resolution TEM, energy dispersive spectroscopy) and selected-area electron diffraction. The typical sample obtained at 433 K in 24 h comprises uniform single-crystal nanofibres with a diameter of ∼15–28 nm and an aspect ratio of 30–50. The influences of treatment time, synthesis temperature and P/La molar ratio are investigated. The phase transition from hexagonal hydrate to monoclinic anhydrous lanthanum phosphate and the growth process of nanofibres are revealed by the experimental results. The formation mechanism of the monoclinic LaPO4is discussed. The result indicates that the P/La ratio does not influence the composition and crystal phase but changes the morphology of the product in the O–HT system.

The Evaporative Decomposition of Solutions Method (Eds) for the Production of Ultrafine Y1Ba2Cu3O7 from Nitrate and Mixed Anion Precursor Solutions

1989 ◽  
Vol 169 ◽  
Author(s):  
Rollin E. Lakis ◽  
Sidney R. Butler
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Barium Carbonate ◽  
Hollow Spheres ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

AbstractY1Ba2Cu3O7 has been prepared by the evaporative decomposition of solutions method. Nitrate and mixed anion solutions were atomized and decomposed at temperatures ranging from 300°C to 950°C. The resulting materials have been characterized using x-ray powder diffraction, Thermal Gravimetric Analysis (TGA), particle size analysis, Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The powder consists of 0.3 micron agglomerated hollow spheres with a primary particle size of 0.06 micron. TGA and x-ray diffraction indicate the presence of barium nitrate and barium carbonate due to incomplete decomposition and/or product contamination by the process environment.

scholarly journals Polystyrene/Montmorillonite Nanocomposites: Study of the Morphology and Effects of Sonication Time on Thermal Stability

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mashael Alshabanat ◽  
Amal Al-Arrash ◽  
Waffa Mekhamer
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Solution Method ◽  
Sonication Time ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Polystyrene Matrix ◽  
Before And After ◽  
Silicate Layers ◽  
Thermal Stability Of

Polymer nanocomposites of polystyrene matrix containing 10% wt of organo-montmorillonite (organo-MMT) were prepared using the solution method with sonication times of 0.5, 1, 1.5, and 2 hours. Cetyltrimethylammonium bromide (CTAB) is used to modify the montmorillonite clay after saturating its surface with Na+ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the montmorillonite before and after modification by CTAB. The prepared nanocomposites were characterized using the same analysis methods. These results confirm the intercalation of PS in the interlamellar spaces of organo-MMT with a very small quantity of exfoliation of the silicate layers within the PS matrix of all samples at all studied times of sonication. The thermal stability of the nanocomposites was measured using thermogravimetric analysis (TGA). The results show clear improvement, and the effects of sonication time are noted.

scholarly journals Modification of Titanium Dioxide Nanoparticles with 3-(Trimethoxysilyl)propyl Methacrylate Silane Coupling Agent

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Thuy-Chinh Nguyen ◽  
Tien-Dung Nguyen ◽  
Duc-Toan Vu ◽  
Duc-Phuong Dinh ◽  
Anh-Hiep Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Tio2 Nanoparticles ◽  
Coupling Agent ◽  
Titanium Dioxide Nanoparticles ◽  
X Ray Diffraction ◽  
Nano Tio2 ◽  
Propyl Methacrylate ◽  
Transmission Electron ◽  
Before And After ◽  
Modification Of Titanium

This paper presents some characteristics, properties, and morphology of TiO2 nanoparticles (nano-TiO2) modified with various contents of 3-(trimethoxysilyl)propyl methacrylate (TMSPM) coupling agent. The treatment process was carried out in ethanol solvent at 50oC using ammonia as a catalyst for hydrolysis reaction of silane to silanol. Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, field emission scanning electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy, and X-ray diffraction methods were used for determination of the characteristics, properties of nano-TiO2 before and after treatment. In addition, the contact angle and grafting efficiency of TMSPM on the surface of TiO2 nanoparticles was also evaluated. The obtained results confirmed that TMSPM was grafted to the TiO2 nanoparticles, the agglomeration of nano-TiO2 was decreased, and surface of TiO2 nanoparticles became hydrophobic after modification by TMSPM.

scholarly journals Characterization of small-scale surface topography using transmission electron microscopy

2018 ◽  
Vol 6 (4) ◽  
pp. 045004 ◽  
Author(s):  
Subarna R Khanal ◽  
Abhijeet Gujrati ◽  
Sai Bharadwaj Vishnubhotla ◽  
Pawel Nowakowski ◽  
Cecile S Bonifacio ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Surface Topography ◽  
Small Scale ◽  
Transmission Electron ◽  
Scale Surface

Study on Microstructure Differences of Coal Samples before and after Loading

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jiajia Liu ◽  
Yingxiang Fang ◽  
Gaini Jia ◽  
Shouqi Chen ◽  
Jianmin Hu
Keyword(s):  
Electron Microscopy ◽  
Coal Seam ◽  
Coal Sample ◽  
Coal Seam Gas ◽  
Adsorbed Gas ◽  
Transmission Electron ◽  
Parallel Layer ◽  
Before And After ◽  
Spectrum Area ◽  
Nmr Techniques

The microscopic pore structure of coal affects the content of adsorbed gas. The microstructure of coal sample before and after loading is different, which will affect the adsorption and permeability of coal seam gas. In order to study this difference, the authors carried out mercury intrusion experiments on coal containing different coal samples and used nondestructive nuclear magnetic resonance (NMR) techniques, scanning electron microscopy, and transmission electron microscopy, to study the microstructure of coal samples before and after loading. The experimental results show that the pores of coal samples are mainly micropores and small pores, and the mesopores and macropores are relatively few. The T2 spectrum area of the coal sample is significantly increased after loading, and the parallel-layer coal samples’ T2 spectrum area is 46735, which is 9112 more than the vertical layer coal samples. The T2 spectrum of the vertical coalbed of saturated water samples shows a three-peak shape, the peak of the T2 spectrum is 12692, and the parallel bedding shows a bimodal morphology. The peak area of the T2 spectrum is 11277. The permeability of the parallel bedding coal sample is good, and the coal sample exhibits anisotropic properties. The pores and cracks of the coal samples increased after loading, and the localized area of the coal sample collapsed and formed a fracture zone, which was not conducive to the occurrence of coal seam gas. Further explanation of the changes in the permeability of the coal sample before and after loading will affect the gas storage and transportation.

Development of a Double Tilt Specimen Heating Holder and its Application for the Study of Phase Transformation of Si3N4 During Sintering

1997 ◽  
Vol 3 (S2) ◽  
pp. 1085-1086
Author(s):  
T. Kamino ◽  
T. Yaguchi ◽  
M. Tomita ◽  
Y. Yasutomi ◽  
K. Hidaka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Elevated Temperatures ◽  
Heating Element ◽  
High Melting ◽  
High Melting Point ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Metal Wires ◽  
Very High

The results of our previous studies revealed that the specimen heating holder with the heating elements of spiral shaped fine metal wires of high melting point enable us to observe high resolution transmission electron microscopy(TEM) images at elevated temperatures.In fact, the holder was applied for high resolution TEM study of a formation of SiC crystal at 1500°C and a surface reconstruction of Au deposited Si particle at 1000°C successfully. However, because the heating holder was single tilt type, there was a certain limitation in its application.In this paper, development of a double tilt specimen heating holder with a heating element of spiral shaped fine metal wire and its application for the study of microstructural changes of Si3N4 during sintering at very high temperature.Photograph of the newly developed double tilt specimen heating holder is shown in Fig. 1. The heating element is mounted on the electrically isolated tilting frame of the holder and the heating current is supplied via tilting rod which is also electrically isolated from other parts of the holder.

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