Effect of Graphene Oxide on the Crystallization of Calcium Carbonate by C3S Carbonation

The effect of graphene oxide (GO) on the crystallization of calcium carbonate (CaCO3) is explored in this paper. Precipitation of CaCO3 was carried out by bubbling carbon dioxide (CO2) through tricalcium silicate (C3S) hydration solution with different graphene oxide admixture contents (0.2%, 1% and 2% mass ratios based on C3S). The polymorph, morphology, crystal size and particle size of CaCO3 were evaluated using X-ray diffraction (XRD), an environmental scanning electronic microscope (ESEM), and laser particle size analysis. The results showed that addition of GO was able to promote the conversion of CaCO3 to a calcite crystal phase with higher thermal stability and crystallinity than the control. However, as the dosage of GO increased, the growth of the calcite crystal particles was somewhat suppressed, resulting in a decrease in the crystal particle size and a narrow particle size distribution. When the amount of GO was 0.2%, 1% and 2%, the crystal size of the calcite was 5.49%, 12.38%, and 24.61% lower than that of the sample without GO, respectively, while the particle size of the calcite also decreased by 17.21%, 39.26%, 58.03%, respectively.

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Dextran-induced modifications of calcium carbonate particles precipitated during carbonatation

Sugar Industry ◽

10.36961/si23369 ◽

2019 ◽

pp. 382-391

Author(s):

Karin Abraham ◽

Liza Splett ◽

Eckhard Flöter

Keyword(s):

Particle Size ◽

Image Analysis ◽

Calcium Carbonate ◽

Filter Cake ◽

Particle Size Analysis ◽

Size Analysis ◽

Shape Parameters ◽

Size And Shape ◽

Static Image ◽

Particle Size And Shape

The effects of high and low molecular mass dextran (T2000 and T40) on the size and shape of particles precipitated during carbonatation and their correlation with filtration performances were key to this study. Varying contents of T2000 and T40 dextran in sugar solutions corresponding to DS contents of thin juice were investigated. For particle size and shape analysis, static image analysis and laser particle size analysis were used. Both methods, static image analysis and laser diffraction, revealed that the presence of T2000 and T40 dextran leads to a higher amount of large-sized particles at the expense of small-sized particles, indicating pronounced agglomeration. The additional evaluation of shape parameters (circularity, roundness, solidity) obtained from static image analysis indicates that the agglomeration is oriented in the absence and in the presence of lower T40 dextran levels. Besides, non-oriented agglomeration, resulting in more round agglomerates with smoother surfaces, was found for samples loaded with T2000 dextran and high T40 dextran levels. Only the latter samples have shown to negatively affect the filtration performance. Thus, in the presence of T2000 dextran and high T40 dextran levels, the filtration was hampered. This appears to be mainly caused by a tighter packing of more round calcium carbonate agglomerates in the porous structure of the filter cake.

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Magnetite (Fe3O4) nanoparticles for chromium removal

Bangladesh Journal of Scientific and Industrial Research ◽

10.3329/bjsir.v53i3.38269 ◽

2018 ◽

Vol 53 (3) ◽

pp. 219-224 ◽

Cited By ~ 2

Author(s):

MT Hossain ◽

MM Hossain ◽

MHA Begum ◽

M Shahjahan ◽

MM Islam ◽

...

Keyword(s):

Particle Size ◽

Fe3o4 Nanoparticles ◽

Crystal Size ◽

Sol Gel ◽

Particle Size Analysis ◽

Wave Number ◽

Size Analysis ◽

Ferric Nitrate ◽

X Ray Diffraction ◽

Magnetite Fe3o4

Magnetite (Fe3O4) nanoparticles were synthesized by sol-gel method using ferric nitrate and ethylene glycol as precursors at 250ºC and 300ºC. X-ray diffraction (XRD) study was used to determine the particle size and structural properties. The microstructural and particle size analysis were carried out using scanning electron microscope (SEM). Magnetite (Fe3O4) nanoparticles were annealed at 250ºC obtained as smaller crystal size than that of 300ºC. Fourier Transform Infrared (FTIR) spectroscopy was used to identify the functional groups of active compound in synthesized magnetite nanoparticles and their corresponding bands were observed in the region between 500cm-1 and 4000cm-1 of infrared radiation. The observed peaks at wave number 574cm-1 and 424cm-1 due to the vibration of tetrahedral and octahedral sites which is indicative the formation of spinel structure of magnetite (Fe3O4). Removal of Cr was found 80% by the synthesized magnetite (Fe3O4) nanoparticles 25g/L at pH 4.0 and contact time was 250 minutes. The results showed that prepared magnetite (Fe3O4) nanoparticles can be used for the treatment of wastewater containing chromium.Bangladesh J. Sci. Ind. Res.53(3), 219-224, 2018

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Iron (III) oxide fabrication from natural clay with reference to phase transformation γ- → α-Fe2O3

Science of Sintering ◽

10.2298/sos1702197s ◽

2017 ◽

Vol 49 (2) ◽

pp. 197-205

Author(s):

Aleksandra Saponjic ◽

Djordje Saponjic ◽

Violeta Nikolic ◽

Maja Milosevic ◽

Milena Marinovic-Cincovic ◽

...

Keyword(s):

Thermal Analysis ◽

Particle Size ◽

Differential Thermal Analysis ◽

Freeze Drying ◽

Magnetic Behavior ◽

Particle Size Analysis ◽

Oxide Powder ◽

Narrow Particle Size Distribution ◽

Size Analysis ◽

Cubic Form

Amorphous iron (III) oxide was obtained from clay, using ammonium hydroxide as a precipitating agent. Influence of freeze drying under vacuum, as a drying method, on particle size, chemical composition, and crystallinity of obtained iron (III) oxide powder was investigated. After freeze drying, precipitate was annealed in air at 500?C and 900?C. X-ray diffraction, particle size analysis, scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis were used to characterize obtained iron (III) oxide powder. All of three powders obtained by freeze drying and annealing, have low crystallinity and particles with irregular layered shape. Narrow particle size distribution was given by an average diameter value of around 50 ?m for all observed powders. Iron-bearing materials like ?-Fe2O3 and ?- Fe2O3 are obtained. Differential thermal analysis curve of obtained samples showed endothermic reaction at 620?C which could be ascribed to phase transition from cubic form ?- ? ?- Fe2O3. Thermal transformations of iron (III) oxide, obtained from clay as a natural source, is suitable to explore in the framework of materials chemistry, and opens the possibility to synthesize materials based on Fe2O3 with specific magnetic behavior.

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Effect of pH, Acid and Thermal Treatment Conditions on Co/CNT Catalyst Performance in Fischer–Tropsch Reaction

Symmetry ◽

10.3390/sym11010050 ◽

2019 ◽

Vol 11 (1) ◽

pp. 50 ◽

Cited By ~ 5

Author(s):

Omid Akbarzadeh ◽

Noor Asmawati Mohd Zabidi ◽

Nor Aliya Hamizi ◽

Yasmin Abdul Wahab ◽

Zulkifli Merican Aljunid Merican ◽

...

Keyword(s):

Particle Size ◽

Thermal Treatment ◽

Fixed Bed ◽

Particle Size Analysis ◽

Treatment Temperature ◽

Bet Surface Area ◽

Narrow Particle Size Distribution ◽

Size Analysis ◽

Fischer Tropsch ◽

Multiwalled Carbon

Multiwalled carbon nanotubes (CNT) supported cobalt oxide was prepared as a catalyst by strong electrostatic adsorption (SEA) method. The CNT support was initially acid- and thermal-treated in order to functionalize the support to uptake more Co clusters. The Co/CNT were characterized by a range of analytical methods including transmission electron microscopy (TEM), temperature programmed reduction with hydrogen (H2-TPR), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic absorption spectroscopy (AAS), Zeta sizer particle size analysis and Brunauer–Emmett–Teller (BET) surface area analysis. TEM images showed cobalt particles were highly dispersed and impregnated at both exterior and interior walls of the CNT support with a narrow particle size distribution of 6–8 nm. In addition, the performance of the synthesized Co/CNT catalyst was tested using Fischer–Tropsch synthesis (FTS) reaction which was carried out in a fixed-bed micro-reactor. H2-TPR profiles indicated the lower reduction temperature of 420 °C was required for the FTS reaction. The study revealed that cobalt is an effective metal for Co/CNT catalysts at pH 14 and at 900 °C calcination temperature. Furthermore, FTS reaction results showed that CO conversion and C5+ selectivity were recorded at 58.7% and 83.2% respectively, which were higher than those obtained using a Co/CNT catalyst which pre-treated at a lower thermal treatment temperature and pH.

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