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

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.

Download Full-text

Freeze drying as a rapid method of disaggregating silts and clays for dry particle size analysis

Journal of Sedimentary Research ◽

10.1306/74d717fd-2b21-11d7-8648000102c1865d ◽

1967 ◽

Vol 37 (3) ◽

pp. 970-971 ◽

Cited By ~ 3

Author(s):

W. B. Charm

Keyword(s):

Particle Size ◽

Rapid Method ◽

Freeze Drying ◽

Particle Size Analysis ◽

Size Analysis

Download Full-text

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

Materials ◽

10.3390/ma12132045 ◽

2019 ◽

Vol 12 (13) ◽

pp. 2045 ◽

Cited By ~ 2

Author(s):

Dapeng Zheng ◽

Haibin Yang ◽

Feng Yu ◽

Bo Zhang ◽

Hongzhi Cui

Keyword(s):

Particle Size ◽

Graphene Oxide ◽

Calcium Carbonate ◽

Crystal Size ◽

Particle Size Analysis ◽

Narrow Particle Size Distribution ◽

Size Analysis ◽

Environmental Scanning ◽

Calcite Crystal ◽

Carbon Dioxide Co2

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.

Download Full-text

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.

Download Full-text