Effects of organic additives and temperature on the structures and morphologies of calcium carbonate crystals in the presence of cetyltrimethylammonium bromide

2008 ◽  
Vol 23 (3) ◽  
pp. 200-203
Author(s):  
Yinxiao Du ◽  
Haixing Hou ◽  
Fanguang Zeng
Keyword(s):  
Calcium Carbonate ◽  
Organic Solvents ◽  
Cetyltrimethylammonium Bromide ◽  
Precipitation Reaction ◽  
Organic Additives ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Structure And Morphology ◽  
Effects Of Temperature ◽  
Diffraction Patterns

Calcium carbonate crystals were prepared via a simple precipitation reaction of sodium carbonate with calcium chloride from mixed solutions of various amphiphilic organic solvents and water in the presence of cetyltrimethylammonium bromide at 25 and 60 °C. Our analysis shows that amphiphilic organic solvents and temperature have large influences on the structure and morphology of CaCO3. X-ray diffraction patterns show that single-phase hexahedral calcite was formed at 25 °C, and orthorhombic aragonite was obtained at 60 °C. Mixtures of major amounts of long aragonite crystals and minor amounts of calcite particles were also obtained at 60 °C in the methanol and the acetone solutions. Scanning electron microscopy images show that CaCO3 particles and aggregates with various morphologies, such as large solid and hollow hexahedral crystals and small round granules of calcite as well as glass-like and wheat-like aggregates of aragonite, were obtained depending on the experimental conditions. Based on the experimental results, a conclusion on the effects of temperature and amphiphilic organic solvents on the crystal structure and morphology are made.

Cetyltrimethylammonium bromide- and ethylene glycol-assisted preparation of mono-dispersed indium oxide nanoparticles using hydrothermal method

2014 ◽  
Vol 68 (8) ◽  
Author(s):  
Selvakumar Dhanasingh ◽  
Dharmaraj Nallasamy ◽  
Saravanan Padmanapan ◽  
Vinod Padaki
Keyword(s):  
Ethylene Glycol ◽  
Hydrothermal Method ◽  
Indium Oxide ◽  
Cetyltrimethylammonium Bromide ◽  
Oxide Nanoparticles ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractThe influence of cetyltrimethylammonium bromide and ethylene glycol on the size and dispersion of indium oxide nanoparticles prepared under hydrothermal conditions was investigated. The precursor compound, indium hydroxide, obtained by the hydrothermal method in the absence as well as the presence of cetyltrimethylammonium bromide, was converted to indium oxide by sintering at 400°C. The formation of nanoscale indium oxide upon sintering was ascertained by the characteristic infrared adsorption bands and X-ray diffraction patterns of indium oxide. Transmission electron microscopy and band gap values confirmed that the cetyltrimethylammonium bromide facilitated the formation of indium oxide nanoparticles smaller in size and narrower in distribution than those prepared without the assistance of cetyltrimethylammonium bromide.

scholarly journals Experimental and Theoretical Studies of Carboxylic Polymers with Low Molecular Weight as Inhibitors for Calcium Carbonate Scale

Crystals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 406 ◽  
Author(s):  
Yuwei Zuo ◽  
Wenzhong Yang ◽  
Kegui Zhang ◽  
Yun Chen ◽  
Xiaoshuang Yin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Calcium Carbonate ◽  
Normal Growth ◽  
Dynamics Simulation ◽  
Low Molecular Weight ◽  
X Ray Diffraction ◽  
Crystal Surfaces ◽  
Molecular Weight Range ◽  
Scale Inhibition ◽  
Diffraction Patterns

Poly acrylic acid (PAA) and polyepoxysuccinic acid (PESA) were investigated as scale inhibitors. The static experiments certified that PAA was superior to PESA for the inhibition of calcium carbonate in the low molecular weight range. The X-ray diffraction patterns suggest that the effect of PAA on the calcite (1 0 4) and (1 1 0) crystal plane was more obvious. Scanning electron microscopy was used to study the surface morphology of the depositions, which indicated that the addition of scale inhibitors could disturb the normal growth of CaCO3 scale. The transmittance ratio of ferric oxide demonstrated that PAA had a better dispersion performance than PESA. The molecular dynamics simulation and quantum calculation were selected to theoretically explore the mechanism and structure of scale inhibitors, indicating that the interaction of PAA with (1 0 4) and (1 1 0) calcite crystal surfaces was stronger than PESA. In addition, the results indicated that the PAA with negative charge more easily adsorbed free Ca2+ in the aqueous phase. Based on these observations, PAA exhibited better scale inhibition and dispersion effects than PESA in the case of low molecular weight.

The Effect of Alcoholic Reducing Agent on Morphology and Structure of VO2 (B) Nano-Particles

2011 ◽  
Vol 306-307 ◽  
pp. 1225-1228 ◽  
Author(s):  
Ji Qi ◽  
Chen Niu
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Raw Materials ◽  
Thermal Reduction ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
Morphology And Structure ◽  
Properties Of Materials ◽  
Scanning Electron

Vanadium dioxides (VO2) is synthesized by hydrothermal method. In this process,V2O5 powder is used as raw materials,cetyltrimethylammonium bromide (CTAB) is used as template and different alcohols such as methanol, ethanol, propanol and butanol are used as reductants. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to test the properties of VO2 nanoparticles. The results show that VO2(B) nano-particles were succsessfully synthesized under the conditions of thermal reduction temperature 180°C, reaction time 24h and drying temperature 60°C. The variety of alcoholic reducing agents plays an important role in the structure and morphology of the product VO2(B), which relates closly to the electric properties of materials.

Optimization of Calcium Carbonate Precipitation for Bacillus pasteurii

2012 ◽  
Vol 178-181 ◽  
pp. 676-679 ◽  
Author(s):  
Tao Duan ◽  
Wen Kun Zhu
Keyword(s):  
Calcium Carbonate ◽  
Crystal Formation ◽  
Carbonate Precipitation ◽  
X Ray Diffraction ◽  
Calcium Carbonate Precipitation ◽  
Electron Microscopic ◽  
Bacillus Pasteurii ◽  
Scanning Electron Microscopic ◽  
External Conditions ◽  
Effects Of Temperature

The effects of temperature, pH, precipitation time, reactant concentration, the crystal formation additive on the yield of calcium carbonate precipitation induced by bacillus pasteurii were investigated through orthogonal test. The morphology and structure of the calcium carbonate were characterized by scanning electron microscopic (SEM), Fourier transform infrared spectroscopy (IR) and powder X-ray diffraction (XRD). The results showed that the optimum conditions of calcium carbonate precipitation induced by bacillus pasteurii were temperature of 40oC, pH of 8, precipitation time of 3 d, Ca2+ of 1.5 mol/L, and Mg2+ of 0.05 mol/L. The crystal of calcium carbonate was calcites or mixture of calcites and vaterite. Its morphology and packing density were changed by different external conditions.

Comparative Crystallinity and Morphology of Enamel, Dentine, Bone and Amorphous Concretions

1970 ◽  
Vol 28 ◽  
pp. 152-153
Author(s):  
Racquel Z. LeGeros ◽  
John P. LeGeros ◽  
Otto R. Trautz ◽  
W. Paul Shirra
Keyword(s):  
Calcium Carbonate ◽  
Amorphous Material ◽  
Apatite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Enamel ◽  
Diffraction Patterns ◽  
Calcified Tissues ◽  
Human Ear

The inorganic phase of calcified tissues of vertebrates he an apatite structure [Ca10(PO4)6(OH)2] while the inorganic phase of the invertebrates such as crustaceans is well crystallized calcium carbonate [CaCO3] in the form of either calcite, aragonite, and sometimes, vaterite. In rare cases, “amorphous” deposits are found such as in the concretions of tapeworm (Saginata Marginata), in the tendon of lobster claw, and in the statoconia of the human ear.Considerable differences in the “crystallinity” of human enamel, bone or dentine, and tapeworm concretions are demonstrated in the size and/or strain broadening of their x-ray diffraction patterns (Fig.1). The pattern of human enamel (1A) demonstrates that it is very well crystallized apatite; whereas the pattern of bone or dentine suggest that it is poorly crystallized (1B); and the pattern of tapeworm concretions (no discernible peaks) indicate an amorphous material (1C).

Low Surface Energy and pH Effect on SnO2 Nanoparticles Formation for Supercapacitor Applications

2019 ◽  
Vol 19 (6) ◽  
pp. 3429-3436
Author(s):  
B Saravanakumar ◽  
G Ravi ◽  
V Ganesh ◽  
S Ravichandran ◽  
A Sakunthala ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Sno2 Nanoparticles ◽  
Ph Effect ◽  
High Specific Capacitance ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Low Surface Energy ◽  
Supercapacitor Applications ◽  
A Current

The SnO2 nanoparticles formation by hydrothermal method at different experimental conditions such as temperature, pH, reaction time, and capping agent (cetyltrimethylammonium bromide), was studied. X-ray diffraction results confirmed regular rutile crystal structure of SnO2. The characteristic Raman peak observed at 635 cm−1 corresponded to A1g modes of Sn–O vibrations. The study of optical property using photoluminescence confirmed the emissive spectra of SnO2. The infrared peak observed at 618 cm−1 corresponded to Eu modes of Sn–O vibrations of TO phonon because of E⊥ to c-axis. Scanning electron microscope images clearly revealed the formation of complete SnO2 nanoparticles. The unique SnO2 nanoparticles stacked together to form microspheres at pH-5 showed high specific capacitance of 274.8 F/g at a current density of 0.5 A/g. The observed results confirmed the feasibility of SnO2 nanoparticles being used as appropriate positive electrode candidate for supercapacitor applications.

Comments on determining X-ray diffraction-based volume fractions of retained austenite in steels

2001 ◽  
Vol 16 (4) ◽  
pp. 198-204 ◽  
Author(s):  
C. K. Lowe-Ma ◽  
W. T. Donlon ◽  
W. E. Dowling
Keyword(s):  
Retained Austenite ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Profile Fitting ◽  
Diffraction Peaks ◽  
Diffraction Patterns ◽  
Heat Treatment Regimes ◽  
Integrated Intensities

Retained austenite is an important characteristic of properly heat-treated steel components, particularly gears and shafts, that will be subjected to long-term use and wear. Normally, either X-ray diffraction or optical microscopy techniques are used to determine the volume percent of retained austenite present in steel components subjected to specific heat-treatment regimes. As described in the literature, a number of phenomenological, experimental, and calculation factors can influence the volume fraction of retained austenite determined from X-ray diffraction measurements. However, recent disagreement between metallurgical properties, microscopy, and service laboratory values for retained austenite led to a re-evaluation of possible reasons for the apparent discrepancies. Broad, distorted X-ray peaks from un-tempered martensite were found to yield unreliable integrated intensities whereas diffraction peaks from tempered samples were more amenable to profile fitting with standard shape functions, yielding reliable integrated intensities. Retained austenite values calculated from reliable integrated intensities were found to be consistent with values obtained by Rietveld refinement of the diffraction patterns. The experimental conditions used by service laboratories combined with a poor choice of diffraction peaks were found to be sources of retained austenite values containing significant bias.

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