scholarly journals Carboxylic acids: effective inhibitors for calcium sulfate precipitation?

2014 ◽  
Vol 78 (6) ◽  
pp. 1465-1472 ◽  
Author(s):  
Taher Rabizadeh ◽  
Caroline L. Peacock ◽  
Liane G. Benning
Keyword(s):  
Electron Microscopy ◽  
Carboxylic Acids ◽  
Calcium Sulfate ◽  
Mineralogical Composition ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron ◽  
Better Than

Results are reported here of an investigation into the effects of three carboxylic acid additives (tartaric, maleic and citric acids) on the precipitation of calcium sulfate phases. Precipitation reactions were followed at pH 7 in the pure CaSO4 system and in experiments with 0–20 ppm carboxylic acids added using in situ UV-VIS spectrophotometry (turbidity). The solid products were characterized in terms of their mineralogical composition, using X-ray diffraction, during and at the end of each reaction, and in terms of their morphological features, by scanning electron microscopy. All additives increased the time needed for turbidity to develop (induction time, start of precipitation) and the comparison between additive and additive-free experiments showed that, at equivalent concentrations, citric acid performed far better than the other two carboxylic acids. In all cases bassanite precipitated first and with time it transformed to gypsum. The addition of citrate stabilized bassanite and changed the final gypsum habit from typical needle-like crystals in the pure CaSO4 system to plates in the citrate-additive experiments.

scholarly journals Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method

2017 ◽  
Vol 62 (2) ◽  
pp. 1005-1010 ◽  
Author(s):  
Peyala Dharmaiah ◽  
C.H. Lee ◽  
B. Madavali ◽  
Soon-Jik Hong
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Figure Of Merit ◽  
Bulk Sample ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coarse Grains ◽  
Scanning Electron ◽  
Nanostructured Sample

AbstractIn the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.

Morphology of Polyethylene/Montmorillonite Nanocomposites Prepared by In Situ Polymerization

2013 ◽  
Vol 457-458 ◽  
pp. 244-247
Author(s):  
Min Li ◽  
Li Guang Xiao ◽  
Hong Kai Zhao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflection Peak ◽  
Basal Reflection ◽  
Scanning Electron

Polyethylene/montmorillonite (PE/MMT) nanocomposites were prepared by in situ polymerization. The morphology of MMT/MgCl2/TiCl4 catalyst and PE/MMT nanocomposites was investigated by scanning electron microscopy (SEM). It can be seen that MMT/MgCl2/TiCl4 catalyst remained the original MMT sheet structures and many holes were found in MMT and the morphology of PE/MMT nanocomposites is part of the sheet in the form of existence, as most of the petal structure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were carried out to characterize all the samples. XRD results reveal that the original basal reflection peak of PEI1 and PEI2 disappears completely and that of PEI3 become very weak. MMT/MgCl2/TiCl4 catalyst was finely dispersed in the PE matrix. Instead of being individually dispersed, most layers were found in thin stacks comprising several swollen layers.

Fabrication of TiAl/Ti2AlC Composite by Reaction Hot Pressing

2011 ◽  
Vol 52-54 ◽  
pp. 842-845 ◽  
Author(s):  
Jian Feng Zhu ◽  
Wen Wen Yang ◽  
Yi Ping Gong
Keyword(s):  
Electron Microscopy ◽  
Reaction Process ◽  
Hot Press ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Composite ◽  
The Matrix ◽  
Morphology Characteristics ◽  
Scanning Electron

TiAl/Ti2AlC in situ composite was successfully fabricated by hot-press-assisted reaction process from the mixture of Ti, Al and carbon black. The phase formation and transformation were investigated in detail by X-ray diffraction (XRD) and the morphology characteristics were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that when the mixed powders were hot pressed at 1300 °C for 1 h, full dense and highly pure TiAl/Ti2AlC composite was synthesized. The TiAl was the matrix phase and the in situ synthesized Ti2AlC was reinforcing phase. The reaction process was also discussed.

Microstructure of In Situ Reaction TiB2/Zn-30Al-1Cu Composites Prepared by Spray Deposition Process

2015 ◽  
Vol 1120-1121 ◽  
pp. 572-575
Author(s):  
Hong Wei Liu ◽  
Feng Wang ◽  
Qiang Zhang ◽  
Xi Wu Li ◽  
Zhi Hui Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spray Deposition ◽  
Deposition Process ◽  
Deposition Technique ◽  
X Ray Diffraction ◽  
X Ray ◽  
Α Phase ◽  
Scanning Electron

An innovative spray deposition technique has been applied to produce in situ TiB2/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using optical microscopy, scanning electron microscopy, and X-ray diffraction. Both theoretical and experimental results have shown that the TiB2particulates are formed in the microstructure. It was found that the TiB2particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB2particles are about 2 μm in size. Moreover, the presence of the TiB2particles was led to increasing of α’ phase with less 2 μm size in the composites which have a tendency to decompose to α+η structure.

Electrical Porcelain Containing Ornamental Rock Waste: Microstructural Development

2010 ◽  
Vol 660-661 ◽  
pp. 692-696 ◽  
Author(s):  
M.A. Silva ◽  
J.N.F. Holanda
Keyword(s):  
Electron Microscopy ◽  
The Other ◽  
Electrical Porcelain ◽  
Microstructural Development ◽  
Chemical Transformations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminous Porcelain ◽  
Physical And Chemical ◽  
Scanning Electron

Aluminous electrical porcelains are used in the production of materials of high voltage insulators. The microstructure plays an important role in the performance of electrical porcelain. On the other hand, the porcelain materials undergo a series of physical and chemical transformations during firing. This makes the understanding of their microstructures rather complex. In this work was studied the microstructural development of electrical porcelain containing up to 35 wt.% of ornamental rock waste. The pieces ceramics were pressed at 50 MPa and sintered at 1300 °C. The porcelain pieces were characterized via X-ray diffraction and scanning electron microscopy. The results indicate that the presence of the ornamental rock waste influenced the microstructural development of the pieces of electrical aluminous porcelain.

Electro-Less Ni-P Plating Coating of In Situ TiCp/Al-4.5wt.%Cu Vomposites

2015 ◽  
Vol 817 ◽  
pp. 593-598
Author(s):  
Yan Feng Liang ◽  
Sheng Quan Dong ◽  
Gao Hong Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Citric Acid ◽  
Optical Microscopy ◽  
X Ray Diffraction ◽  
Citric Acid Concentration ◽  
X Ray ◽  
In Situ Tic ◽  
Scanning Electron

In situ TiCp/Al-4.5wt.%Cu composites have been coated using an electro-less Ni-P plating technique. The morphology and composition of the plating coating have been examined by scanning electron microscopy, optical microscopy, and X-ray diffraction. The results indicated that the coating had a high-phosphorus amorphous microstructure. The coatings microstructures showed significantly changes when the citric acid concentration in the chemical bath was varied in the range 16-20g/L.

Spray dried hydroxyapatite-polyvinyl alcohol biocomposites

2016 ◽  
Vol 36 (8) ◽  
pp. 795-804 ◽  
Author(s):  
Tuğba Başargan ◽  
Nalan Erdöl-Aydın ◽  
Gülhayat Nasün-Saygılı
Keyword(s):  
Electron Microscopy ◽  
Polyvinyl Alcohol ◽  
Spray Dryer ◽  
Drying Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pva Solutions ◽  
Spray Dried ◽  
Scanning Electron

Abstract In this study, hydroxyapatite/polyvinyl alcohol (HAp-PVA) biocomposites were prepared using a spray drying method. HAp-PVA solutions fed to spray dryer were prepared by two different routes, namely, physical and in situ biomimetric methods. In the former method, HAp was synthesized without the presence of polymer and then HAp particles were incorporated into a PVA solution. In the second one, hydroxyapatite was in situ synthesized in the presence of PVA. Experiments were also run to investigate the effect of the molecular weight of PVA on the structure of spray-dried biocomposites. Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and particle size analyses were performed to characterize the produced HAp-PVA composites.

Microstructure Evolution of In Situ Synthesized VC Reinforced Iron Matrix Composites

2012 ◽  
Vol 217-219 ◽  
pp. 71-74
Author(s):  
Jing Wang ◽  
Si Jing Fu ◽  
Shu Yong Jiang ◽  
Hong Cheng
Keyword(s):  
Electron Microscopy ◽  
In Situ Synthesis ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
Iron Matrix ◽  
X Ray ◽  
Matrix Microstructure ◽  
The Matrix ◽  
Scanning Electron

Iron matrix composite reinforced with VC reinforcements was produced by in situ synthesis technique. The microstructure of the composites was characterized by X-ray diffraction and scanning electron microscopy. The micrographs revealed the morphology and distribution of the reinforcements. The results show that the composite consists of VC carbide as the reinforcing phase and α-Fe as the matrix. The distribution of spherical VC particulates in iron matrix is uniform, and the matrix microstructure of Fe-VC composite is pearlite.

scholarly journals Synthesis of Zeolite A employing Amazon kaolin waste

Cerâmica ◽  
2015 ◽  
Vol 61 (360) ◽  
pp. 409-413 ◽  
Author(s):  
S. H. da Silva Filho ◽  
L. Bieseki ◽  
A. R. da Silva ◽  
A. A. B. Maia ◽  
R. A. S. San Gil ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Amorphous Materials ◽  
Mas Nmr ◽  
The Other ◽  
Zeolite A ◽  
X Ray Diffraction ◽  
X Ray ◽  
27Al Mas Nmr ◽  
Scanning Electron

Abstract The synthesis of zeolite A employing kaolin waste from paper coating was studied. The kaolin waste was pre-treated at 550 to 800 ºC. For comparison purposes, a sample of zeolite A was also prepared using the IZA procedure. The materials were characterized by 27Al MAS NMR, X-ray diffraction and scanning electron microscopy using a microprobe. Pretreatment was necessary, and the best temperatures were between 600 and 700 ºC. The zeolite A formation was observed in all the prepared materials, reaching 52% crystallinity. On the other hand, the sodalite phase and amorphous materials were also formed.

Template-Free Synthesis of α-Fe2O3 Hollow Spheres and Nanocubes

2011 ◽  
Vol 361-363 ◽  
pp. 2012-2015
Author(s):  
Chang Yun Chen ◽  
Feng Zhou ◽  
Chun Hua ◽  
Zhao Hui Li ◽  
Huan Pang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hollow Spheres ◽  
Magnetic Characteristic ◽  
The Other ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Template Free ◽  
Scanning Electron

A facile hydrothermal method without any templates has been developed for the preparation of α- Fe2O3nanocubes and hollow spheres. The as-synthesized products is then characterized using X-ray diffraction(XRD), scanning electron microscopy(SEM). The nanocubes have extraordinary unity and we can anticipate its unique magnetic characteristic. On the other hand, the hollow sphere structure has a promising future in the application as carriers for targeting drug delivery. In our opinions, the method is not only very simple, but also is very friendly to the environment.

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