scholarly journals Reactivity of Coke. II. Effects of Heat Treatment of Cokes on Their Specific Surface Areas and Absolute Specific Reaction Rates with Carbon Dioxide at 950°C

1954 ◽  
Vol 27 (6) ◽  
pp. 334-339 ◽  
Author(s):  
Yoshio Kawana
Keyword(s):  
Carbon Dioxide ◽  
Heat Treatment ◽  
Specific Surface ◽  
Reaction Rates ◽  
Specific Reaction ◽  
Surface Areas ◽  
Specific Surface Areas

scholarly journals Construction of Oxygen-Rich Carbon Foams for Rapid Carbon Dioxide Capture

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 173
Author(s):  
Cheng Duan ◽  
Wei Zou ◽  
Zhongjie Du ◽  
Jianguo Mi ◽  
Jiaxi Han ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Oxygen Content ◽  
Total Pore Volume ◽  
Micropore Volume ◽  
Surface Areas ◽  
Oil In Water ◽  
Carbon Foams ◽  
Specific Surface Areas ◽  
Carbon Dioxide Co2

As carbon dioxide (CO2) adsorbents, porous materials with high specific surface areas and abundant CO2-philic groups always exhibit high CO2 capacities. Based on this consensus, a category of oxygen-rich macroporous carbon foams was fabricated from macroporous resorcinol-formaldehyde resins (PRFs), which were obtained via an oil-in-water concentrated emulsion. By the active effect of potassium hydroxide (KOH) at high temperatures, the resultant carbon foams (ACRFs) possessed abundant micropores with rich oxygen content simultaneously. At the same time, most of the ACRFs could retain the marcoporous structure of their precursor. It is found that porosity of ACRFs was mainly determined by carbonization temperature, and the highest specific surface areas and total pore volume of ACRFs could reach 2046 m2/g and 0.900 cm3/g, respectively. At 273 K, ACRFs showed highest CO2 capacity as 271 mg/g at 1 bar and 91.5 mg at 15 kPa. Furthermore, it is shown that the ultra-micropore volume was mainly responsible for the CO2 capacities of ACRFs at 1 bar, and CO2 capacities at 15 kPa were mainly affected by the oxygen content. It is also found that the presence of macropores would accelerate ACRFs adsorbing CO2. This study provides ideas for designing a porous CO2 adsorbent.

scholarly journals Ultrafine porous boron nitride nanofibers synthesized via a freeze-drying and pyrolysis process and their adsorption properties

RSC Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 1253-1259 ◽  
Author(s):  
Jing Lin ◽  
Lulu Xu ◽  
Yang Huang ◽  
Jie Li ◽  
Weijia Wang ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Specific Surface ◽  
Freeze Drying ◽  
Adsorption Properties ◽  
Pyrolysis Process ◽  
Surface Areas ◽  
Aspect Ratios ◽  
Large Pore ◽  
Specific Surface Areas

Ultrafine porous boron nitride nanofibers with high aspect ratios, high specific surface areas and large pore volumes has been synthesized in large quantity via a freeze-drying and post pyrolysis process.

scholarly journals Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Gang Zhou ◽  
Han Qiu ◽  
Qi Zhang ◽  
Mao Xu ◽  
Jiayuan Wang ◽  
...  
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Specific Surface ◽  
Coal Dust ◽  
Single Point ◽  
Contact Angles ◽  
Critical Surface ◽  
Volume Percentage ◽  
Surface Areas ◽  
Specific Surface Areas

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

Facile Method To Synthesize Mesoporous Multimetal Oxides (ATiO3, A = Sr, Ba) with Large Specific Surface Areas and Crystalline Pore walls

2010 ◽  
Vol 22 (4) ◽  
pp. 1276-1278 ◽  
Author(s):  
Xiaoxing Fan ◽  
Ying Wang ◽  
Xinyi Chen ◽  
Ling Gao ◽  
Wenjun Luo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Areas ◽  
Specific Surface Areas

Carbon Microspheres Prepared by High Internal Phase Emulsion Polymerization

2011 ◽  
Vol 239-242 ◽  
pp. 3105-3108
Author(s):  
Ming Xian Liu ◽  
Li Hua Gan ◽  
Jun Hu ◽  
Hong Lai Liu ◽  
Long Wu Chen
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Aqueous Phase ◽  
Apparent Density ◽  
Tween 80 ◽  
Carbon Microspheres ◽  
High Internal Phase Emulsion ◽  
Surface Areas ◽  
Internal Phase ◽  
Specific Surface Areas

In this paper, we present a novel approach for the synthesis of carbon microspheres via the polymerization of a high internal phase emulsion (HIPE). By using Span 80 and Tween 80 as emulsifiers, 1iquid paraffin as oil phase, and the mixture of resorcinol/formaldehyde (R/F) solution as aqueous phase, an O/W emulsion was obtained. This emulsion phase inverted to a W/O HIPE induced by ammonia which served as the polymerization catalyst. Carbon microspheres (CMs) were prepared by polymerization of the HIPE, followed by drying and carbonization. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) analyzer were used to characterize as-prepared CMs. The results indicate that, in case of 0.25 wt% ammonia of the HIPE, the diameters of CMs decreased from about 2 to 1 μm when the mass fraction of aqueous R/F decreased from 0.714 to 0.357; the apparent density and the specific surface areas of the CMs, however, did not change obviously, which are about 0.6 g/cm3and 200 m2/g, respectively. The dosage of ammonia has a significant influence on the morphology and properties of CMs. With increasing of the ammonia mass to 1 wt% of the HIPE, the resultant carbon materials comprise not only CMs, but also some carbon sheets; the apparent density of which increased to 0.9 g/cm3and the specific surface areas of which decreased to below 100 m2/g. In addition, the other parameters for CMs preparation were also investigated. It was found that the proper conditions were controlling the temperature of 303-333 K and the oil/aqueous phase mass ratio of 2.5:7.

The Experimental Study on Grinding Properties of Gas Quenching Steel Slag

2011 ◽  
Vol 189-193 ◽  
pp. 612-617
Author(s):  
Hong Wei Xing ◽  
Yue Long ◽  
Xiu Li ◽  
Gao Liang Li ◽  
Yu Zhu Zhang ◽  
...  
Keyword(s):  
Specific Surface ◽  
New Technology ◽  
Steel Slag ◽  
Economic Benefits ◽  
Surface Areas ◽  
Mineral Phases ◽  
Quenching Process ◽  
Gas Quenching ◽  
Specific Surface Areas ◽  
Better Than

A gas quenching process to deal with steel slag and its characteristics of the new technology was briefly introduced. The grinding characteristics, mineral phases of gas quenching steel slag and the potential economic benefits of using it as cement mixing material was studied by compared to heat-stew steel slag. The results indicated that the specific surface areas (S) and grinding times (t) of the gas quenching steel slag showed a first order exponential decay relationship. With the extension of time, the specific surface areas of heat-stew steel slag was tending to balance earlier than that of gas quenching steel slag; The energy consumption of gas quenching steel slag was much lower than that of heat-stew steel slag. Gas quenching steel slag was comprised of C2S, C3S, a certain amount of (Ca2(Al, Fe)2O5）and RO phase, but the content of RO phase was relatively low, which increased the grindability of the quenching steel slag, so that the grindability of gas quenching steel slag was much better than that of heat-stew steel slag. Gas quenching steel slag prepared for cement addictives would bring great economic benefits.

scholarly journals Photocatalytic activity of CaTaO2N nanocrystals obtained from a hydrothermally synthesized oxide precursor

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Specific Surface ◽  
Morphological Properties ◽  
Soft Chemistry ◽  
Co Catalyst ◽  
Surface Areas ◽  
Oxide Precursor ◽  
Photocatalytic Activities ◽  
Specific Surface Areas

Highly crystalline CaTaO2N nanoparticles possessing large specific surface areas were investigated as photocatalysts for the decomposition of methyl orange. Two different Ca2Ta2O7 precursors were synthesized by classical solid state synthesis and a hydrothermal soft-chemistry approach, respectively. In both cases, nitridation was carried out by thermal ammonolysis. The obtained CaTaO2N samples were compared with respect to their optical, thermal and morphological properties as well as their photocatalytic activities. In particular, the influence of ammonolysis temperature on the photocatalytic properties was studied. Using hydrothermally synthesized Ca2Ta2O7, phase pure CaTaO2N was obtained already at a relatively low ammonolysis temperature of 860 °C. Morphological investigations show that the CaTaO2N samples from the hydrothermally synthesized precursor consist of single-crystalline particles of 45 to 70 nm diameter with high specific surface areas between 12 and 19 m2 g-1, depending on ammonolysis temperature. A considerable photocatalytic activity for methyl orange degredation was found for the nanoscaled CaTaO2N particles prepared at lower ammonolysis temperatures. Using CoOx as co-catalyst, a further strong enhancement of the methyl orange decomposition by a factor 5-10 was achieved.

scholarly journals Catalytic Decomposition of H2O2 over Pure and Li2O-Doped Co3O4 Solids

1998 ◽  
Vol 16 (9) ◽  
pp. 733-746 ◽  
Author(s):  
Gamil A. El-Shobaky ◽  
Nagi R.E. Radwan ◽  
Farouk M. Radwan
Keyword(s):  
Heat Treatment ◽  
Specific Surface ◽  
Catalytic Decomposition ◽  
Nitrogen Adsorption ◽  
Progressive Increase ◽  
Lithium Oxide ◽  
Lithium Nitrate ◽  
Surface Areas ◽  
Catalytically Active ◽  
Cobaltic Oxide

Pure and doped Co3O4 samples were prepared by the thermal decomposition at 500–900°C of pure and lithium nitrate-treated basic cobalt carbonate. The amounts of dopant added were varied in the range 0.75–6 mol% Li2O. The effects of this treatment on the surface and catalytic properties of cobaltic oxide solid were investigated using nitrogen adsorption at −196°C and studies of the decomposition of H2O2 at 30–50°C. The results obtained revealed that Li2O doping of Co3O4 followed by heat treatment at 500°C and 600°C resulted in a progressive increase in the value of the specific surface area, SBET, to an extent proportional to the amount of dopant present. However, the increase was more pronounced in the case of solid samples calcined at 500°C. This increase in the specific surface areas has been attributed to the fixation of a portion of the dopant ions on the uppermost surface layers of the solid leading to outward growth of the surface lattice. The observed increase in SBET due to Li2O doping at 500°C might also result from a narrowing of the pores in the treated solid as a result of the doping process. Lithium oxide doping of cobaltic oxide followed by heat treatment at 700–900°C resulted in a significant decrease in the SBET, Vp and r̄ values. Pure and doped solids precalcined at 500°C and 600°C exhibited extremely high catalytic activities which were not much affected by doping with Li2O. On the other hand, doping followed by calcination at 700–900°C brought about a considerable and progressive increase in the catalytic activity of the treated solids. This treatment did not modify the activation energy of the catalysed reaction, i.e. doping of Co3O4 solid followed by heating at 700°C and 900°C did not alter the mechanism of the catalytic reaction but increased the concentration of catalytically active constituents taking part in the catalytic process without altering their energetic nature.

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