scholarly journals Investigations of Latvian Illite/Kaolinite Clays Irradiated Under Action of Accelerated Electrons

2019 ◽  
Vol 26 (1) ◽  
pp. 99-102
Author(s):  
Dāvis CONKA ◽  
Līga AVOTINA ◽  
Ruta SVINKA ◽  
Visvaldis SVINKA ◽  
Laris BAUMANE ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Absorbed Dose ◽  
Free Fraction ◽  
Natural Clay ◽  
Ir Spectrometry ◽  
Accelerated Electrons ◽  
Ft Ir

Natural clay is a perspective material for application as sorbents for wastewater treatment as well as for sorption of radionuclides, where the properties of the clays can be changed under influence of ionizing radiation. For application of Latvian illite/kaolinite clays for isotope sorption it is important to characterize the physic-chemical properties of pre-prepared air dried clays. Two fractions of the illite clays were selected. A fraction with grain size 100 μm (SiO2 content 60.9 ± 1.5 wt.%, specific surface area 35 m2/g) and a sand free fraction – 2 μm (SiO2 47.7 ± 1.9 wt.%, specific surface area 38 m2/g). Selected fractions were irradiated with accelerated electrons (5 MeV, ELU-4, Salaspils, absorbed dose up to 500 kGy). Non-irradiated and irradiated clays were analysed with means of Fourier transform infrared (FT-IR) spectrometry.  

scholarly journals Optimization of compositions and technology of production of small-clinker floured cements using the most effective fillers

2021 ◽  
Vol 136 (3) ◽  
pp. 46-55
Author(s):  
N.B. Sarsenbayev ◽  
◽  
B.K. Sarsenbayev ◽  
Zh.T. Aimenov ◽  
A.Zh. Aimenov ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Crystalline Structure ◽  
Specific Surface Area ◽  
Chemical Properties ◽  
Surface Layers ◽  
Fine Powders ◽  
Energy Demands ◽  
Actual Evaluation ◽  
Technology Of Production

Considering the physical chemistry of grinding it is worth quoting the grinding of mineral building material as “the change of physical-chemical properties of finely ground materials can not only be due to the reducing the particle sizes, at mechanical grinding significant changes of the crystalline structure of their surface layers (thickness 15-20 microns) take place, in many cases the technological properties of fine powders are not so much due to dispersability but are namely due to the structure rupture”, at that the energy costs for this are “significantly greater than for the exposal of surfaces with a clean cleavage”. The speed of heterogeneous chemical processes involving fine powders is determined primarily not by the magnitude of their specific surface area, as commonly is believed, but by the decrease of energy of activation as the result of crystalline structure rupture and amorphization. However, both specific surface area and energy demands to achieve are actual evaluation of the effectiveness of any material grinding at a particular unit. The main factor of the production process of cements of low water demand is the grinding, characterized by grindability.

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.

Ultrasonic-Microwave Synergistic Synthesis of RGO–Bi2WO6 Photocatalyst with High Photoactivity for Basic Nitrogen Compounds in Light Oil

NANO ◽  
2016 ◽  
Vol 11 (05) ◽  
pp. 1650052 ◽  
Author(s):  
Ying Chen ◽  
Shenglun Ji ◽  
Tengfei Qiao ◽  
Shuang Miao ◽  
Yu Zhao
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Composite Catalyst ◽  
Photogenerated Carrier ◽  
X Ray Diffraction ◽  
Composite Photocatalyst ◽  
Photocatalytic Activities ◽  
Light Oil ◽  
Ft Ir

Graphene–Bi2WO6 composite photocatalyst with excellent photocatalytic properties were synthetized by ultrasonic-microwave synergistic method. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier infrared (FT-IR) spectrum, specific surface area analyzer (BET) and UV-Vis diffuse reflectance spectra. The photocatalytic activities of as-prepared samples were evaluated by degradation of pyridine in light oil under visible light irradiation. The results show that graphene changed appearance structure of Bi2WO6, which prevented the Bi2WO6 nanosheets reunion arrangement, and increased specific surface area of the catalyst. It can also reduce the recombination probability of photogenerated carrier, so as to improve the photocatalytic activity of the composite catalyst. The optimal amount of graphene is 2%, with the denitrification rate as high as 89.28%, much higher than that of pure Bi2WO6.

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.

Property of Nanoporous Metal-Organic Frameworks at Different Synthesis Temperature

2012 ◽  
Vol 427 ◽  
pp. 123-127
Author(s):  
Yuan Hui Ma ◽  
Lei Zhang ◽  
Cheng Chun Tang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reaction Temperature ◽  
Metal Organic Frameworks ◽  
Synthesis Temperature ◽  
Structure Stability ◽  
Nanoporous Metal ◽  
Metal Organic ◽  
Ft Ir

The nanoporous metal-organic frameworks were synthesized under solvothermal conditions using organic solvent dimethylformamide. The samples were characterized by XRD, SEM, TGA, FT-IR and specific surface area for their properties difference. When the reaction temperature rises, the particle size becomes larger. All TGA curves are the basically same, the framework structure begins to be destroyed from 500°C up to around 600°C. The metal-organic frameworks accepted at reaction temperature 190°C have larger specific surface area and better structure stability.

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.

scholarly journals Preparation and photocatalytic activity of the layered titanates

2010 ◽  
Vol 4 (2) ◽  
pp. 69-73 ◽  
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. .

scholarly journals Investigation of Nickel Ion Removal by Means of Activated Clay

1992 ◽  
Vol 9 (4) ◽  
pp. 244-257 ◽  
Author(s):  
S. Hawash ◽  
J.Y. Farah ◽  
M.S. El-Geundi
Keyword(s):  
Activated Carbon ◽  
Economic Analysis ◽  
Specific Surface ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Specific Surface Area ◽  
Wastewater Analysis ◽  
Natural Clay ◽  
Nickel Ion ◽  
Ion Removal

Natural and activated clays have been investigated as adsorbents for the removal of nickel from wastewater. Analysis of the natural clay under test showed that it was composed, approximately of 51% kaolinite, 46% montmorillonite and 3% illite, having a specific surface area of 65 m2/g. The natural clay was treated with different activators (HCl, NaCl and H2O2) to enhance its adsorption capacity towards nickel. The efficiency of such activation was greater by 16.0% and 23.2% in the case of NaCl and H2O2, respectively, relative to untreated clay. No significant increase in the adsorption capacity was brought about by HCl treatment. A limited comparison has been made between clay and activated carbon by performing isotherm studies under similar conditions. The results indicate that the adsorption capacity of clay activated with H2O2, clay activated with NaCl and natural clay is 216.9%, 204.2% and 176.1% that of activated carbon, respectively. Based solely on the adsorption capacity, an economic analysis demonstrates that natural clay is the cheapest material, followed by clay activated with NaCl and clay activated with H2O2. The relative costs of removing nickel using natural clay, clay activated with NaCl and clay activated with H2O2 were found to be 2.8%, 5.4% and 25.4%, respectively, that of activated carbon.

Sintesis Zeolit Terlapis Cupferron dan Aplikasinya Sebagai Adsorben Cu(II)

2019 ◽  
Vol 2 (2) ◽  
Author(s):  
Ngatijo ◽  
Faizar Farida ◽  
Purmaida S Sihombing ◽  
Rahmat Basuki
Keyword(s):  
Specific Surface ◽  
Pore Size ◽  
Surface Area ◽  
Specific Surface Area ◽  
Ft Ir ◽  
Ir Analysis

Zeolit-cupferron berhasil disintesis yang dikonfirmasi dengan data FT-IR, XRD dan SSA. Zeolit-cupferron disintesis dengan teknik pencampuran antara zeolite teraktivasi dan cupferron dengan rasio 0,5; 1,0; dan 1,5 : 10 (g :mL) selama 2 jam dan campuran yang dipeorleh dipisahkan dengan teknik sentrifugasi dan dikeringkan pada 50oC. Berdasarkan hasil analisis, luas permukaan spesifik zeolite pasca pelapisan dengan cupferron mengalami penurunan, namun ukuran pori mengalami peningkatan. Kristalinitas zeolite pasca pelapisan tidak mengalami perubahan yang signifikan tetapi berdasarkan analisis FT-IR keberadaan cupferron pada permukaan zeolite dapat dikonfirmasi. Rasio terbaik antara zeolite dan cupferron adalah 1,5 : 10. Kondisi optimum untuk aplikasi material zeolite-cupferron sebagai adsorben untuk Cu (II) adalah pada pH 5.   Zeolite-cupferron was successfully synthesized based on FT-IF, XRD, and SSA analysis. Zeolite-cupferron was synthesized by mixing technique by mixing the activated zeolite and cupferron at ratio 0,5, 1,0, and 1,5 : 10 (g:mL) for 2 h stir and then the mixture was centrifuged and dried at 50 °C. The result was the specific surface area of zeolite after coating by cupferron was decrease, hoever the pore size was increasing. Crystallinity after coating was not changed significantly but from FT-IR analysis reinforce the presumption that cupferron coated on zeolite. The best ratio of zeolite (g) and cupferron (mL) was 1,5:10. Application of zeolite-cupferron in adsorption Cu(II) onto this material optimum at pH = 5.

Producing biochars with enhanced surface activity through alkaline pretreatment of feedstocks

Soil Research ◽  
2010 ◽  
Vol 48 (7) ◽  
pp. 606 ◽  
Author(s):  
K. Hina ◽  
P. Bishop ◽  
M. Camps Arbestain ◽  
R. Calvelo-Pereira ◽  
J. A. Maciá-Agulló ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Sink ◽  
Bet Specific Surface Area ◽  
Carbon Recovery ◽  
Ft Ir ◽  
Low Temperature Pyrolysis ◽  
Enhanced Surface ◽  
Cp Mas 13C Nmr

Surface-activated biochars not only represent a useful carbon sink, but can also act as useful filtering materials to extract plant nutrients (e.g. NH4+) from wastes (e.g. animal or municipal waste streams) and added thereafter to soils. Biochars produced by low-temperature pyrolysis of fibrous debarking waste from pine (PI) and eucalyptus (EU) were pre-treated with either diluted (L) or undiluted (S) alkaline tannery waste (L-PI, S-PI, L-EU, S-EU). Biochars produced from untreated feedstock were used as controls. Samples were characterised by FT-IR, solid-state CP MAS 13C NMR, XPS, SEM microphotographs, and BET specific surface area. Elemental composition, carbon recovery, yield, surface charge, and NH4+ sorption/desorption properties were also studied. Carbon recovery was lower in biochars prepared from L-EU and S-EU (43 and 42%, respectively) than in control EU (45%) but these biochars showed greater changes in their chemical characteristics than those made from L-PI and S-PI, which showed minimal decrease in recovered carbon. The specific surface area of the biochars decreased with treatments, although acidic surface groups increased. In subsequent sorption experiments, treated biochars retained more NH4+ from a 40 mg N/L waste stream (e.g. 61% retention in control EU and 83% in S-EU). Desorption was low, especially in treated biochars relative to untreated biochars (0.1–2% v. 14–27%). The results suggest that surface activated biochars can be obtained with negligible impairment to the carbon recovered.

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