Effects of Wet Grinding Process on the Properties of the Ground Diatomite Particles

Wet grinding of diatomite was carried out in a stirred mill. The changes in particle size, specific surface area and structure or the particle shape in the wet grinding process were investigated. The adsorption of methylene blue from aqueous solution by the ground diatomite was also studied. X-ray diffraction (XRD), scanning electron microscopy (SEM) and IR spectra were employed to characterize the ground diatomite. The median particle size decreased and the specific surface area increased with the grinding time, an agglomeration phenomenon was not observed during the experimental grinding time. The X-ray diffraction patterns versus grinding time showed that a peak intensity reduction of opal. The results of adsorption of methylene blue onto diatomite indicated the adsorption capacity increases with the increase of grinding time until eventually reaches a constant value.

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Effects of dry grinding on pyrophyllite

Clay Minerals ◽

10.1180/claymin.1988.023.4.07 ◽

1988 ◽

Vol 23 (4) ◽

pp. 399-410 ◽

Cited By ~ 40

Author(s):

J. L. Pérez-Rodríguez ◽

L. Madrid Sánchez del Villar ◽

P.J. Sánchez-Soto

Keyword(s):

Electron Microscopy ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Grinding Process ◽

X Ray Diffraction ◽

X Ray ◽

Dry Grinding ◽

Scanning Electron ◽

Area Data

AbstractDry grinding of pyrophyllite (Hillsboro, USA) has been studied by X-ray diffraction (XRD), specific surface area measurements (BET) and scanning electron microscopy (SEM). At the beginning of the grinding process, some effects such as delamination, gliding and folding of the layers, and decrease in particle size were detected by SEM and XRD, resulting in a large increase in specific surface area, up to a maximum of ∼60 m2·g−1. Marked changes in the structure take place between 30 and 32 mins grinding. Longer grinding times increase the degree of disorder and SEM and specific surface area data suggest that aggregation occurs. XRD results indicate that some residual order persists in the degraded structure.

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MECHANOCHEMICAL SYNTHESIS OF CALCIUM TITANATE AND RESEARCH OF ITS PHOTOCATALYTIC ACTIVITY

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/tcct.20165906.5384k ◽

2018 ◽

Vol 59 (6) ◽

pp. 83 ◽

Cited By ~ 1

Author(s):

Konstantin V. Ivanov ◽

Alexandr V. Agafonov ◽

Olyga V. Alexeeva

Keyword(s):

Particle Size ◽

Photocatalytic Activity ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Biological Tissues ◽

Calcium Titanate ◽

Ceramic Technology ◽

X Ray Diffraction ◽

X Ray

Recently much attention is paid to the synthesis and study of the properties of inorganic materials, based on alkaline earth titanates with a perovskite structure that have various polymorphic forms depending on the temperature. Calcium titatanat (CaTiO3) can be selected from the variety of perovskites because of its relatively high dielectric constant, unique photochemical properties, chemical stability, and compatibility with biological tissues, which leads to its application in microelectronics, photocatalysis and biomedicine as bone implants. In this paper, a solid-phase synthesis of calcium titanate was carried out by ceramic technology using mechanochemistry methods. This method allows to obtain calcium titanate directly by mechanochemical activation from the initial mixture of Ca (OH)2 and TiO2, which significantly reduces the energy consumption for its production. Structural changes in the synthesized material during calcination at 120 °C, 200 °C, 400 °C, 600 °C, and 800 °C were studied. The particle size and specific surface area of powders synthesized and calcined at 800 °C was measured by laser diffraction ("Analysette 22") and the low temperature (77K) nitrogen adsorption-desorption vapor, respectively. The phase composition of the obtained materials was studied by X-ray diffraction. It was found on the basis of studies of the particle size distribution that synthesized and calcined powders contain nanoparticles with sizes of 377 and 422 nm. The samples of CaTiO3 calcined at 120 °C and 800 °C have a mesoporous structure, the specific surface area was 46 and 7 m2/g, respectively, and average pore size in powders was 4 nm. It was found by the X-ray diffraction technique that the uncalcined sample contains admixtures of CaCO3 and TiO2 that can be removed completely at 600 °C.The photocatalytic activity of the synthesized material has been studied by the example of Rhodamine B dye decoloration on the calcium titanate calcined at 800°C. It was found that the decomposition degree of dye in solution was 77% for 80 min at a 6.7% shadow adsorption.

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Study of Heating Effect on Specific Surface Area, and Changing Optical Properties of ZnO Nanocrystals

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.403-408.1205 ◽

2011 ◽

Vol 403-408 ◽

pp. 1205-1210

Author(s):

Jaleh Babak ◽

Ashrafi Ghazaleh ◽

Gholami Nasim ◽

Azizian Saeid ◽

Golbedaghi Reza ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Energy Gap ◽

Sol Gel ◽

X Ray Diffraction ◽

X Ray ◽

Zno Nanocrystals ◽

Transmission Electron ◽

Zno Nanocrystal

In this work ZnO nanocrystal powders have been synthesized by using Zinc acetate dehydrate as a precursor and sol-gel method. Then the products have been annealed at temperature of 200-1050°C, for 2 hours. The powders were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence (PL) spectroscopy. The morphology of refrence ZnO nanoparticles have been studied using Transmission Electron Microscope (TEM). During the annealing process, increase in nanocrystal size, defects and energy gap quantitative, and decrease in specific surface area have been observed.

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Study of Gamma Alumina Synthesis – Analysis of the Specific Surface Area

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.87.54 ◽

2014 ◽

Vol 87 ◽

pp. 54-60 ◽

Cited By ~ 2

Author(s):

A.H. Munhoz ◽

H. de Paiva ◽

L. Figueiredo de Miranda ◽

E.C. de Oliveira ◽

Raphael Cons Andrades ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Ageing Time ◽

Precursor Solution ◽

Specific Area ◽

Gamma Alumina ◽

X Ray Diffraction ◽

X Ray ◽

Dta And Tg

Different samples of pseudoboehmite (PB) were synthesized through the sol-gel process, using aluminum nitrate as precursor. The influence of variables on the synthesis and calcinations of the PB on the specific area of the obtained gamma-Alumina were studied. The variables were the ageing temperature (25 and 130o C), addition or not of polyvinyl alcohol to the precursor solution and the ageing time of the PB. The pH adjustment of the precursor solution was made by using ammonium carbonate. The products, which were obtained on different conditions, were then characterized by x-ray diffraction, specific area measurements through the BET process, and by thermal analysis (DTA and TG). After characterization, the synthesis products were calcined at 500°C; during this process the gamma-Alumina transformation was observed. The calcination products were characterized by the same methods (x-ray diffraction, BET, DTA and TG) and the desorption-absorption curves were obtained as well, in order to measure the pore volume of the samples. Finally, the results were analyzed through an experimental factorial planning, which showed that high specific surface area gamma-Al2O3 (around 330m²/g) can be obtained through this process.

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Preparation and photocatalytic activity of the layered titanates

Processing and Application of Ceramics ◽

10.2298/pac1002069m ◽

2010 ◽

Vol 4 (2) ◽

pp. 69-73 ◽

Cited By ~ 12

Author(s):

Marija Milanovic ◽

Ivan Stijepovic ◽

Ljubica Nikolic

Keyword(s):

Photocatalytic Activity ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

High Photocatalytic Activity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Bet Method ◽

Ft Ir

Titanate structures were synthesized in highly alkaline solution using hydrothermal procedure. As-prepared powders were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). A specific surface area of the powders was measured by BET method. Results confirmed formation of layered trititanates, already after one hour of hydrothermal synthesis. To examine the photocatalytic activity of the as-prepared layered titanates, methylene blue (MB) was employed as a target compound in response to visible light at ambient temperature. It was observed that the specific surface area, size distribution and crystallinity are important factors to get high photocatalytic activity for the decomposition of MB. .

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W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽

10.3390/proceedings2130836 ◽

2018 ◽

Vol 2 (13) ◽

pp. 836

Author(s):

Ambra Fioravanti ◽

Sara Morandi ◽

Alessia Amodio ◽

Mauro Mazzocchi ◽

Michele Sacerdoti ◽

...

Keyword(s):

Zinc Oxide ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Mixed Oxides ◽

Gas Sensing ◽

Molar Fraction ◽

Functional Materials ◽

X Ray Diffraction ◽

X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

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CO2 utilization by dry reforming of CH4 over mesoporous Ni/KIT-6 catalyst

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2021-0006 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Congming Tang ◽

Juan Huang ◽

Dong Zhang ◽

Qingqing Jiang ◽

Guilin Zhou

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Photoelectron Spectroscopy ◽

Pore Diameter ◽

Co2 Utilization ◽

X Ray Diffraction ◽

X Ray ◽

Catalytic Performances

Abstract The mesoporous Ni/KIT-6 catalysts with different composition were prepared by altering reduction temperatures. In addition, their physicochemical properties were characterized by X-ray diffraction, in-situ X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller techniques. The results shown that the specific surface area, composition and metallic Ni crystallinity of the Ni/KIT-6 catalyst were significantly affected by reduction temperatures. The catalytic performances of the prepared Ni/KIT-6 catalysts were evaluated via the CO2 reforming of CH4 into syngas and followed the order: RT0 < RT250 < RT300 < RT350 < RT400 < RT450 ≈ RT500. The specific surface area, pore volume, pore diameter, and Ni0 content of the most representative RT450 catalyst among of them were 646.7 m2 g−1, 0.92 cm3 g−1, 6.5 nm, and 30.9%, respectively. The CH4 and CO2 conversions of RT450 catalyst reached to 69.0 and 39.4% under a reaction temperature of 600 °C, respectively. The CO selectivity was greater than 49% and the RT450 catalyst had good stability.

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Synthesis of micro-mesopores flowerlike γ-Al2O3 nano-architectures

Journal of the Serbian Chemical Society ◽

10.2298/jsc130903007a ◽

2014 ◽

Vol 79 (8) ◽

pp. 1007-1017 ◽

Cited By ~ 18

Author(s):

Mozaffar Abdollahifar ◽

Reza Zamani ◽

Ehsan Beiygie ◽

Hosain Nekouei

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Pore Volume ◽

Total Pore Volume ◽

High Specific Surface Area ◽

X Ray Diffraction ◽

N2 Adsorption ◽

X Ray ◽

Adsorption Desorption

The micro-mesopores flowerlike ?-Al2O3 nano-architectures have been synthesized by thermal decomposition method using the synthesized AlOOH (boehmite) as precursor. After calcination at 500?C for 5 h, the obtained flowerlike ?-Al2O3 has similar structure like the AlOOH precursor. X-ray diffraction (XRD), FTIR, TG, FESEM and TEM techniques were used to characterize morphology and structure of the synthesized samples. The specific surface area (BET), pore volume and pore-size distribution of the products were determined by N2 adsorption-desorption measurements. The flowerlike ?-Al2O3 showed BET high specific surface area 148 m2 g-1 with total pore volume 0.59 cm3 g-1.

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Fabrication of Porous MoS2 with Controllable Morphology and Specific Surface Area for Hydrodeoxygenation

NANO ◽

10.1142/s1793292017501168 ◽

2017 ◽

Vol 12 (09) ◽

pp. 1750116 ◽

Cited By ~ 3

Author(s):

Zhenwi Zhang ◽

Chuanjun Yue ◽

Jianhen Hu

Keyword(s):

Electron Microscopy ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Smooth Surface ◽

High Selectivity ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Large Sheet

SiO2 nanoparticles modified with aminopropyl-triethoxysilane (APTES) were used as hard templates for preparing porous MoS2. The method offers the advantages of simple steps, convenient operation, controllable pore size, and a specific surface area. Two morphologies of MoS2 were obtained by using thiourea and L-cysteine as sulfur sources, respectively. Porous MoS2 prepared by using thiourea had a smooth surface, whereas the surface of porous MoS2 prepared with L-cysteine had many burrs. The MoS2 nanomaterials with the respective morphologies were used to catalyze the hydrodeoxygenation (HDO) reaction. The activity of MoS2 prepared with L-cysteine was lower than that prepared with thiourea. Transmission electron microscopy and X-ray diffraction analyses showed that MoS2 had a large sheet-shaped structure and high crystallinity, leading to high reaction activity and high selectivity for cyclohexane. The reaction temperature also influenced the HDO significantly. The mechanism of hydrogenation of phenol was discussed.

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