scholarly journals Preparation of silicon and alumosilicic aerogels based on the decomposition of nepheline with an alcoholic solution of sulfuric acid

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 54-59
Author(s):  
Yu. O. Velyaev ◽  
◽  
D. V. Maiorov ◽  
I. B. Kometiani ◽  
◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Specific Surface ◽  
Elemental Analysis ◽  
Pore Volume ◽  
Average Pore Size ◽  
Alcoholic Solution ◽  
Average Pore ◽  
Skeletal Density ◽  
X Ray ◽  
Chemical Purity

The results of studies on the production of silicon and aluminum-silicon aerogels from nepheline are presented. The morphology of the obtained samples was studied. Their chemical purity was proved by the method of X-ray elemental analysis. The structural and surface properties of the resulting aerogel are presented, such as: specific surface area (843.62 и 503.99 m2/g) and pore volume (0.396 и 0.237 cm3/g), average pore size (1.870 nm). Data on the skeletal density of the obtained samples are given

Preparation and Structural Analysis of Magnesium Oxide Aerogels

MRS Advances ◽  
2017 ◽  
Vol 2 (57) ◽  
pp. 3505-3510
Author(s):  
Jiankai Zhang ◽  
Xiaohong Chen ◽  
Ran Liu ◽  
Huaihe Song ◽  
Zhihong Li
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Magnesium Oxide ◽  
Specific Surface Area ◽  
Average Pore Size ◽  
Sol Gel ◽  
Average Pore ◽  
X Ray ◽  
Water As Solvent ◽  
Saxs Analysis

ABSTRACTMagnesium oxide aerogels were made by sol-gel process using magnesium methoxide as precursor, methanol and deionized water as solvent with ethanol supercritical fluid drying. The influences of the different factors on the gel time and the specific surface area of magnesium oxide aerogels were studied, and the structure and morphology were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscope (TEM) and X-ray diffraction (XRD), and the Small Angle X-ray Scatter (SAXS) was utilized to determine the fractural structure of the magnesium oxide aerogels. The results show that MgO aerogels belong to the typical mesoporous materials with rich network and highly developed pore structure, and the specific surface area is 904.9 m2/g, the apparent density is 0.055 g/cm3, the average pore size is 19.6 nm. The results of SAXS analysis show that the fractal dimension of the MgO aerogels is 2.32 in high q area which proves the existence of rough surface and pore fractal structure.

scholarly journals INFLUENCE OF SYNTHESIS TECHNO-CHEMICAL PARAMETERS ON PHYSICOCHEMICAL CHARACTERISTICS OF BIOMIMETIC CALCIUM-PHOSPHATE NANOCOMPOSITE DOPED BY SILICATE AND CARBONATE ANIONS

2020 ◽  
Vol 5 (10) ◽  
pp. 47-56
Author(s):  
M. Troubitsin ◽  
Viet Hung Hoang ◽  
L. Furda
Keyword(s):  
Calcium Phosphate ◽  
Specific Surface ◽  
Crystallite Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Average Pore Size ◽  
Average Crystallite Size ◽  
Average Pore ◽  
The Impact

The object of our investigation is a biomimetic calcium-phosphate nanocomposite doped by silicate and carbonate anions (BMHAP) synthesized by chemical deposition from aqueous solutions. The obtained samples are investigated using X-ray phase analysis (XRD), FTIR spectroscopy, and low-temperature nitrogen adsorption (BET method). The influence of the techno chemical synthesis parameters on the products characteristics (including phase composition, crystal lattice parameters, average crystallite size, specific surface area) is evaluated. The study on the effect of the synthesis temperature shows that with increasing in temperature from 22°C to 80°C, reveals a slight increase in the parameters of unit cells a and c, which leads to an increase in its volume. There is also a tendency towards a decrease in the average size of coherent scattering regions of crystallites (from 7,52 to 4,65 nm) and specific surface area (from 192,51 to 74,72 m2/g), but the pore volume and average pore diameter of the synthesized powders increases. The effect of the aging time of the sediment in the mother liquor is studied from 0,5 to 24 hours. It is found that with an increase in the maturation time of the sediment, the percent crystallinity of the powders improves by 1,7 times, an increase in the specific surface area from 163,43 to 192,51 m2/g and a slight decrease in the pore volume and average pore size of the samples are observed. The impact of the stirring rate of the reagents is investigated. An increase in speed from 300 to 1300 rpm has been shown to decrease the average crystallite size from 8,80 to 6,41 nm, and as a result, to increase the specific surface area of the synthesized samples from 178,58 to 192,51 m2/g, respectively.

Fuels Desulphurisation by Adsorbtion on Fe / Bentonite

2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Pore Diameter ◽  
Adsorption Process ◽  
Continuous System ◽  
Gas Oil ◽  
Average Pore ◽  
Atmospheric Distillation

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.

Investigate on Pore Structure Characteristics of Reactive Powder Concrete after High Temperatures

2012 ◽  
Vol 174-177 ◽  
pp. 1010-1014 ◽  
Author(s):  
Hong Bin Liu ◽  
Yang Ju ◽  
Kai Pei Tian ◽  
Jin Hui Liu ◽  
Li Wang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Pore Size ◽  
Pore Volume ◽  
Average Pore Size ◽  
Reactive Powder Concrete ◽  
Characteristic Parameters ◽  
Average Pore ◽  
Structure Characteristics ◽  
Temperature Levels ◽  
Reactive Powder

The pore structure characteristics of reactive powder concrete (RPC) were investigated by means of the mercury injection method at seven temperature levels, namely, 20°C, 100°C, 150°C, 200°C, 250°C, 300°C, 350°C, respectively. The characteristic parameters such as porosity, pore volume, average pore size and threshold aperture varied with temperatures were analyzed. The results indicate that the porosity, pore volume, threshold aperture and other characteristic parameters of RPC increased with the temperature increasing.

Effects of Sintering Temperature on the Properties of Stainless Steel Foam

2015 ◽  
Vol 1087 ◽  
pp. 232-235
Author(s):  
Fazimah Mat Noor ◽  
N.I. Mad Rosip ◽  
Khairur Rijal Jamaludin ◽  
Sufizar Ahmad
Keyword(s):  
Stainless Steel ◽  
Average Pore Size ◽  
Vacuum Furnace ◽  
Stainless Steel 316L ◽  
Average Pore ◽  
X Ray ◽  
Replication Method ◽  
Pore Dimension ◽  
Steel Foam ◽  
Highly Porous

Foam replication method is capable of producing foams with a highly porous structure with adjustable pore dimension, shape and size. In this work, this method has been used to prepare stainless steel 316L foam and sintered at 1200°C, 1250°C and 1300°C in a vacuum furnace. The microstructure and elemental analysis of the sample were examined using scanning electron microscope (SEM) and Energy Dispersive X–Ray (EDX), while the mechanical properties of the samples was determined by using compression test. It was found that the average pore size was in the range of 330µm-350µm. The yield strength and elastic modulus are in the range of 58-66 GPa and 0.46-0.50GPa respectively.

scholarly journals Evaluation of dolomite as catalyst in the transesterification reaction using palm oil (RBD)

DYNA ◽  
2019 ◽  
Vol 86 (209) ◽  
pp. 180-187
Author(s):  
Stephanie Alexa Ñústez Castaño ◽  
Duvan Oswaldo Villamizar Castro ◽  
Edgar Mauricio Vargas Solano
Keyword(s):  
Palm Oil ◽  
Batch Reactor ◽  
Methyl Esters ◽  
Average Pore Size ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Average Pore ◽  
X Ray ◽  
Rbd Palm Oil ◽  
Methyl Ester Content

In this study, the catalytic activity of dolomite was evaluated for the transesterification of Colombian RBD palm oil with methanol, carried out in a batch reactor at 333,15K and 600rpm. The activated dolomites (calcined at 1073.15K for 2h) were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Hammett indicators method, and quantification of the surface area, average pore size and average pore volume BET. The influence of reaction variables such as catalyst amount (%wt /wt) and methanol / palm oil molar ratio (mole/mole) was investigated. Under the suitable reaction conditions, the amount of calcined dolomite equal to 4% (wt /wt) based on the weight of oil, the methanol-oil molar ratio equal to 9:1, and the reaction time = 1h, the methyl ester content of 82.67% of fatty acid methyl esters (FAME) can be achieved.

scholarly journals Acid Modification of the Unsupported NiMo Catalysts by Y-Zeolite Nanoclusters

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 344
Author(s):  
Chengwu Dong ◽  
Changlong Yin ◽  
Tongtong Wu ◽  
Zhuyan Wu ◽  
Dong Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Average Pore Size ◽  
Y Zeolite ◽  
Active Components ◽  
Acid Modification ◽  
Total Acid ◽  
Average Pore ◽  
Nimo Catalysts

Unsupported NiMo catalyst has high hydrogenation activity due to its high active site distribution. However, low specific surface area and pore distribution greatly limit the efficient utilization of the active components. The Y-zeolite nanoclusters were hydrothermally synthesized and introduced into the unsupported NiMo catalysts from a layered nickel molybdate complex oxide. The XRD, N2 adsorption-desorption, FT-IR, Py-IR, SEM, NH3-TPD, and TEM were used to characterize all catalysts. The dibenzothiophene (DBT) hydrodesulfurization (HDS) reaction was performed in a continuous high pressure microreactor. The results showed that the specific surface area, pore volume, and average pore size of the unsupported NiMo catalysts were greatly increased by the Y-zeolite nanoclusters, and a more dispersed structure was produced. Furthermore, the Lewis acid and total acid content of the unsupported NiMo catalysts were greatly improved by the Y-zeolite nanoclusters. The HDS results showed that the unsupported NiMo catalysts modified by the nanoclusters had the same high desulfurization efficiency as the unmodified catalyst, but had more proportion of direct desulfurization (DDS) products. The results offer an alternative to reducing hydrogen consumption and save cost in the production of ultra clean diesel.

Polymer Embedded Nanocrystalline Titania Sorbent for 99Mo-99mTc Generator

2008 ◽  
Vol 8 (9) ◽  
pp. 4447-4452 ◽  
Author(s):  
Rubel Chakravarty ◽  
Rakesh Shukla ◽  
Shyamla Gandhi ◽  
Ramu Ram ◽  
Ashutosh Dash ◽  
...  
Keyword(s):  
Saline Solution ◽  
Average Pore Size ◽  
Average Crystallite Size ◽  
Activity Level ◽  
X Ray Diffraction ◽  
Average Pore ◽  
X Ray ◽  
Nano Crystalline ◽  
99Mtc Generator

A new sorbent material, polymer embedded nano crystalline titania (Titanium Polymer-TiP) has been developed, from titanium (IV) chloride and isopropyl alcohol, for the adsorption of 99Mo, which is a precursor to 99mTc, a workhorse in radio-pharmaceuticals. The infrared absorption spectra of the TiP showed peaks corresponding to Ti-O groups. X-ray diffraction pattern of the adsorbent corresponded to rutile TiO2. The surface area of this polymer was 30 m2/g with an average pore size of 40 nm. The average crystallite size of TiO2, embedded in polymer, was found to be 5 nm. TEM micrograph of the adsorbent revealed the networkof polymer with dispersed titania phase. Potential of this adsorbent for the preparation of 99Mo-99mTc generator has been explored. 99Mo could be adsorbed on to the adsorbent column containing TiP at pH 1 from which 99mTc could be eluted with normal (0.9%) saline solution with an elution yield of ∼80%. The quality of the 99mTcO−4 obtained was in accordance with the international specifications applicable for radiopharmaceutical use. A process demonstration run was carried out with 1.1 GBq (30 mCi) 99Mo activity level making use of the above adsorbent and consistent results were obtained over a period of one week, which is generally the shelf life of 99Mo-99mTc generator.

Preparation of Iron Catalysts Generated from Fe-Coagulated Sludge Produced by Ferric Chloride Coagulation of Wastewater

2014 ◽  
Vol 1025-1026 ◽  
pp. 645-650
Author(s):  
Supranee Foowut ◽  
Tawanrat Palothaisit ◽  
Natthadabhorn Boonlor ◽  
Panida Prompinit ◽  
Pinsuda Viravathana
Keyword(s):  
Specific Surface ◽  
Pore Volume ◽  
Total Pore Volume ◽  
Iron Catalysts ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Precipitation ◽  
X Ray Absorption ◽  
Xanes Analysis

In this work, the FexOy catalysts were prepared by the co-precipitation method. The catalysts were characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and Brunauer-Emmett-Teller (BET) surface analysis. From XRD results, the FexOy with the wastewater to coagulant ratio of 1:2 catalyst (FexOy-1:2) calcined at 600 °C for 6 h showed the presence of the wustite (FeO) form. XANES analysis showed the phase of FeO in FexOy-1:2 calcined at 600 °C for 6 h which corresponded to the result from XRD. The FexOy 1:1 catalyst had higher specific surface area and larger total pore volume compared to the FexOy 1:2 catalyst.

scholarly journals Biodiesel Processing Using Sodium and Potassium Geopolymer Powders as Heterogeneous Catalysts

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2839 ◽  
Author(s):  
Renata F. Botti ◽  
Murilo D.M. Innocentini ◽  
Thais A. Faleiros ◽  
Murilo F. Mello ◽  
Danilo L. Flumignan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Heterogeneous Catalysts ◽  
Average Pore Size ◽  
Thermal Shrinkage ◽  
Average Pore ◽  
Base Catalysts ◽  
Sodium And Potassium

This work investigates the catalytic activity of geopolymers produced using two different alkali components (sodium or potassium) and four treatment temperatures (110 to 700 °C) for the methyl transesterification of soybean oil. The geopolymers were prepared with metakaolin as an aluminosilicate source and alkaline activating solutions containing either sodium or potassium in the same molar oxide proportions. The potassium-based formulation displayed a higher specific surface area and lower average pore size (28.64–62.54 m²/g; 9 nm) than the sodium formulation (6.34–32.62 m²/g; 17 nm). The reduction in specific surface area (SSA) after the heat treatment was more severe for the sodium formulation due to the higher thermal shrinkage. The catalytic activity of the geopolymer powders was compared under the same reactional conditions (70–75 °C, 150% methanol excess, 4 h reaction) and same weight amounts (3% to oil). The differences in performance were attributed to the influences of sodium and potassium on the geopolymerization process and to the accessibility of the reactants to the catalytic sites. The Na-based geopolymers performed better, with FAME contents in the biodiesel phase of 85.1% and 89.9% for samples treated at 500 and 300 °C, respectively. These results are competitive in comparison with most heterogeneous base catalysts reported in the literature, considering the very mild conditions of temperature, excess methanol and catalyst amount and the short time spent in reactions.

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