Research on Obtaining Silica Xerogels from Nepheline and Study of some of their Physical and Chemical Properties

2020 ◽  
Vol 989 ◽  
pp. 121-126
Author(s):  
Yuriy Velyaev ◽  
Dmitry Maiorov ◽  
Ilona Kometiani
Keyword(s):  
Specific Surface ◽  
Chemical Properties ◽  
Mesoporous Structure ◽  
Silica Gels ◽  
Silica Xerogels ◽  
Nepheline Concentrate ◽  
Concentrate Acid ◽  
Chemical Purity ◽  
Physical And Chemical ◽  
Low Solubility

The article presents a method to obtain silica xerogels with developed specific surface based on nepheline concentrate acid decomposition in C2H5OH-H2SO4 system. It was found that the use of ethanol instead of water produces stable and steady silica gels. It is proved that the use of ethanol results in almost complete deposition of soda alum and aluminum potassium sulphate out of nepheline decomposition solution without its additional cooling, due to their extremely low solubility in alcohol solution. The morphology, structural and surface properties of synthesized xerogel sample with ~600 m2/g specific surface area (based on the analysis) were investigated; its mixed micro-and mesoporous structure was established. Electron probe microanalysis showed chemical purity of the resulting SiO2.

scholarly journals Influence of the Calcination Temperature on the properties of The Alumina as Catalyst Support for Catalysis

Paliva ◽  
2020 ◽  
pp. 155-161
Author(s):  
Tomáš Hlinčík ◽  
Veronika Šnajdrová ◽  
Veronika Kyselová
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Catalyst Support ◽  
Chemical Properties ◽  
Total Pore Volume ◽  
Temperature Range ◽  
Calcination Temperatures ◽  
Physical And Chemical

Alumina is commonly used in industrial practice as a catalyst support and it is made from boehmite. Depending on the calcination temperature, this mineral is transformed into various crystalline modifications which have different physical and chemical properties. For this reason, the following parameters were determined at different calcination temperatures: length, width, material hardness, specific surface area and total pore volume. The results show that with increasing calcination temperature there have been significant changes which may be important when using the material as a catalyst support, e.g. in the preparation of catalysts or in the design of cat-alytic reactors. The specific surface area, which decreases in the temperature range 450–800 °C, is an important parameter for the preparation of catalysts, so it is appropriate to choose a temperature of 600 °C, when the specific surface area is above 200 m2·g-1. The effect of calcination temperature on the structural transitions of boehmite was also monitored. The results showed that γ-Al2O3 has the most suitable properties as a catalyst sup-port in the temperature range 450–800 °C.

Some Physical, Chemical and Mineralogical Properties of Some Canadian Fly Ashes

1986 ◽  
Vol 86 ◽  
Author(s):  
R. C. Joshi ◽  
B. K. Marsh
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Water Soluble ◽  
Pozzolanic Activity ◽  
Unburned Carbon ◽  
Magnetic Fraction ◽  
Fly Ashes ◽  
Physical And Chemical

ABSTRACTThis paper gives physical and chemical properties of some Canadian fly ashes. Specific surface area, magnetic fraction, water soluble fraction and fraction finer than 45 μm were determined as part of the physical tests. Thermo-gravimetric analyses (TGA) in oxygen and nitrogen were conducted on raw ash samples. The change of pH with time in suspensions of the different ashes in water was also determined. Pozzolanic activity of the ashes with lime for all the ashes was evaluated to measure ash reactivity.The ash activity seems to be related to fineness of the ash measured by the Blaine air permeability method, but not to the fineness measured by nitrogen sorption. Generally the greater the specific surface area, the higher the reactivity of the ash. The correlation was, however, not strong and no other physical or chemical parameter measured in this investigation seems to be related to pozzolanic activity.The results of pH and TGA tests indicated that the ashes differ in many respects from each other. The TGA data suggest that loss on-ignition in many of the ashes is not entirely due to the presence of unburned carbon. Specific surface area determined by various methods seems to provide different values. No characterization parameter was found that was uniquely related to coal type.

Physical and Chemical Properties of CaCl2/H2O and LiBr/H2O Systems Confined to Nanopores of Silica Gels

1996 ◽  
Vol 457 ◽  
Author(s):  
Yurii I. Aristov ◽  
Mikhail M. Tokarev ◽  
Gaetano Cacciola ◽  
Giovanni Restuccia ◽  
Gaetano DiMarco ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Partial Pressure ◽  
Specific Heat ◽  
Chemical Properties ◽  
Silica Gels ◽  
Physical And Chemical Properties ◽  
Sorbed Water ◽  
Vapor Partial Pressure ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTHere we present physical and chemical properties of CaCl2/H2O and LiBr/H2O systems confined to nanopores of silica gels. Sorption isobars, isosters and isotherms were measured at temperature 293 – 423K and vapor partial pressure 8–133 mbar. Specific heat of the systems was found as a function of temperature (300 – 400K) and sorbed water content (0 – 53 wt.%). Solidification/melting diagrams were measured over 170 – 320K temperature range at salt concentrations 0–50 wt.%. The results obtained evidenced a significant change in the thermodynamic properties of CaCl2/H2O and LiBr/H2O systems due to confinement to the silica gel micropores.

scholarly journals Characterization of Samarium Doped Ceria Powders Having High Specific Surface Area Synthesized by Carbon-Assisted Spray Pyrolysis

2011 ◽  
Vol 485 ◽  
pp. 137-140 ◽  
Author(s):  
Kenichi Myoujin ◽  
Hiroki Ichiboshi ◽  
Takayuki Kodera ◽  
Takashi Ogihara
Keyword(s):  
Specific Surface ◽  
Relative Density ◽  
Spray Pyrolysis ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Sources ◽  
Chemical Properties ◽  
High Specific Surface Area ◽  
Doped Ceria ◽  
Physical And Chemical

Spherical samarium doped ceria (Ce0.8Sm0.2O1.9, SDC) powders having high specific surface area (SSA) were successfully synthesized by carbon-assisted spray pyrolysis (CASP). Saccharides, such as monosaccharides and disaccharides, or organic acids were used as carbon sources. The physical and chemical properties of these powders were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Thermo gravimetry-Differential Thermal Analysis (TG-DTA), and BET. Decarbonized powders obtained by this method exhibit spherical morphologies and nano- and submicron-sizes. The SSA of SDC obtained from CASP was more than seven times higher than that obtained from conventional spray pyrolysis (CSP). The SSA of the decarbonized SDC powders obtained by calcination at 900 °C was estimated to be approximately 70 m2/g by using the BET method. The relative density of SDC obtained from CASP was higher than that obtained from CSP. The relative density of the SDC pellet was highest (96 %) when it was sintered at 1400 °C.

The Progress and Application of High Specific Surface Materials in Environmental Protection

2012 ◽  
Vol 518-523 ◽  
pp. 898-902
Author(s):  
Ting Ting Fu ◽  
Ning Zhang ◽  
Yong Hui Zhou ◽  
Hong Min Kan ◽  
Xiao Yang Wang
Keyword(s):  
Specific Surface ◽  
Environmental Protection ◽  
Pollution Control ◽  
Chemical Properties ◽  
Activated Carbon Fiber ◽  
Adsorptive Capacity ◽  
Air Pollution Control ◽  
Surface Materials ◽  
Physical And Chemical ◽  
Redox Characteristic

High specific surface materials were widely applied in water pollution control, air pollution control and recycling of organic solvents due to their excellent physical and chemical properties such as large specific surface area, redox characteristic, high adsorption and desorption speed and large adsorptive capacity. The characteristics of activated carbon fiber, nanometer titanium dioxide and their applications in environmental protection such as air purification, the treatment of drinking water and industrial wastewater and the recycling of organic solvent were investigated in present work.

scholarly journals Pt Nanoparticles Supported on Nitrogen doped Carbon as an Efficient Catalyst for Decalin Dehydrogenation

2020 ◽  
Vol 194 ◽  
pp. 02025
Author(s):  
Huiru Yun ◽  
Zhuo Li ◽  
Shiguang Fan ◽  
Jian Wang ◽  
He Liu
Keyword(s):  
Chemical Properties ◽  
Pt Nanoparticles ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Efficient Catalyst ◽  
Transmission Electron ◽  
Mean Size ◽  
Nitrogen Doped Carbon ◽  
Physical And Chemical

A novel Pt/CN catalyst was synthesized by sodium borohydride treatment. The physical and chemical properties of Pt/CN catalyst were characterized by X-ray diffraction (XRD), brunner-emmet-teller (BET), transmission electron microscope (TEM) and High-resolution transmission electron microscopy (HRTEM). The characterized results showed that the catalyst has a high specific surface area, mesoporous structure and the mean size of Pt nanoparticles is 2.59 nm. Subsequently, the catalytic performance of Pt/CN catalyst for decline dehydrogenation was studied. Pt/CN catalyst exhibited excellent performance in decalin dehydrogenation with the conversion of decalin was 30.70%, and the selectivity of naphthalene was 90.86% at 200 ℃ for 150 minutes. When the reaction temperature increased to 210 ℃, the conversion of catalyst increased to 52.02%, and the selectivity of naphthalene reduced to 90.21%. The possible reason may be attributed to the difficulty in converting decalin to tetralin. This paper would provide a novel method for the synthesis of efficient dehydrogenation catalyst of decalin..

scholarly journals High Bulk Modulus of Ionic Liquid and Effects on Performance of Hydraulic System

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Milan Kambic ◽  
Roland Kalb ◽  
Tadej Tasner ◽  
Darko Lovrec
Keyword(s):  
Ionic Liquid ◽  
Bulk Modulus ◽  
Chemical Properties ◽  
Dynamic Responses ◽  
Hydraulic Fluid ◽  
Hydraulic Systems ◽  
Mineral Oils ◽  
Physical And Chemical ◽  
High Bulk ◽  
Low Solubility

Over recent years ionic liquids have gained in importance, causing a growing number of scientists and engineers to investigate possible applications for these liquids because of their unique physical and chemical properties. Their outstanding advantages such as nonflammable liquid within a broad liquid range, high thermal, mechanical, and chemical stabilities, low solubility for gases, attractive tribological properties (lubrication), and very low compressibility, and so forth, make them more interesting for applications in mechanical engineering, offering great potential for new innovative processes, and also as a novel hydraulic fluid. This paper focuses on the outstanding compressibility properties of ionic liquid EMIM-EtSO4, a very important physical chemically property when IL is used as a hydraulic fluid. This very low compressibility (respectively, very high Bulk modulus), compared to the classical hydraulic mineral oils or the non-flammable HFDU type of hydraulic fluids, opens up new possibilities regarding its usage within hydraulic systems with increased dynamics, respectively, systems’ dynamic responses.

Relationship Between Particle Size Distribution and Specific Surface Area of Urban Roadway Stormwater Solids

1997 ◽  
Vol 1601 (1) ◽  
pp. 95-108 ◽  
Author(s):  
John J. Sansalone ◽  
Steven G. Buchberger ◽  
Joseph M. Koran ◽  
Joseph A. Smithson
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Particle Surface ◽  
Chemical Properties ◽  
Spherical Particles ◽  
Particle Surface Area ◽  
Surface Areas ◽  
Physical And Chemical ◽  
And Chemical Properties

Surface area is a primary factor in determining many physical and chemical properties of solids, especially particles. In urban and highway runoff, solids can mediate the partitioning between the dissolved and particulate-bound phases of metal elements and organic compounds. Solids are also capable of adversely affecting roadway drainage appurtenances through sedimentation and clogging. Solids characteristics of primary importance for both solute adsorption and clogging and sedimentation are particle size distributions (PSDs), specific surface areas (SSAs), and mass loadings. PSD and SSA results are presented for rainfall and snowmelt solids from a heavily traveled urban roadway in Cincinnati. Integration of the PSD and SSA results indicates that particle surface area is greatest for the midrange (> 100 μm) to the coarser end (<2000 μm) of the gradation. SSA results determined using the assumption of smooth spherical particles are indicated to grossly underestimate actual SSA values.

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