scholarly journals Possibility of Using t-Plots, Obtained from Nitrogen Adsorption for the Valuation of Zeolites

1986 ◽  
Vol 3 (3) ◽  
pp. 159-166 ◽  
Author(s):  
P. Hudec ◽  
J. Novanský ◽  
S. Silhár ◽  
T. N. Trung ◽  
M. Zúbek ◽  
...  
Keyword(s):  
Specific Surface ◽  
Quantitative Estimation ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Bet Analysis ◽  
Zeolite Content ◽  
Synthetic Zeolites ◽  
Specific Surface Areas ◽  
Specific Volumes

Data of adsorption isotherms of nitrogen adsorption at 77 K on various samples of zeolites were measured. Besides derivation of specific surface area by BET analysis, samples were characterised by values obtained by t-plots; specific surface areas of mesopores and specific volumes of micropores are also calculated. Results show the value of the use of t-plot method for the characterization of microporosity changes in zeolites after various treatments, and also for quantitative estimation of zeolite content in natural zeolites and the crystallinity of synthetic zeolites.

scholarly journals Study of sepiolite from Goles (Kosovo, Yugoslavia). II. Acid activation

2002 ◽  
Vol 67 (7) ◽  
pp. 499-506 ◽  
Author(s):  
Marina Radojevic ◽  
Vidojko Jovic ◽  
Dragomir Karaulic ◽  
Dragomir Vitorovic
Keyword(s):  
Specific Surface ◽  
Chemical Treatment ◽  
Acid Treatment ◽  
Nitrogen Adsorption ◽  
Adsorption Properties ◽  
Acid Activation ◽  
Surface Areas ◽  
Bet Method ◽  
Specific Surface Areas ◽  
Enhanced Adsorption

The changes in the pore structure and adsorption properties of sepiolite from Goles resulting from treatment with 4MHCl for various periods of time were investigated. The BET method specific surface areas, pore volumes and f ? plots were determined by nitrogen adsorption. The surface area progressively increased during the 70 hours of acid treatment, when a maximum was attained. The differences in the adsorption properties of the original and the acid treated sepiolite were evaluated by comparison of adsorption isotherms obtained with benzene, n-hexane, methanol and isooctane. The enhanced adsorption of isooctane was of great interest, since the sorption of this compound on natural sepiolites is generally very limited. The results suggest that chemical treatment of sepiolite with 4MHCl for 70 h produces an adsorbent of optimal porosity and other adsorption properties.

Nitrogen adsorption on synthetic akaganeite and its structural implications

Clay Minerals ◽  
1977 ◽  
Vol 12 (4) ◽  
pp. 345-352 ◽  
Author(s):  
E. Paterson ◽  
J. M. Tait
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Nitrogen Adsorption ◽  
Structural Scheme ◽  
Qualitative And Quantitative ◽  
Surface Areas ◽  
Two Samples ◽  
Specific Surface Areas ◽  
Adsorptive Properties ◽  
Quantitative Assessments

AbstractComparison of the adsorptive properties of two samples of akaganéite prepared by different methods shows that a structural scheme based upon solid rods is much more likely than a previously proposed scheme involving tubes. Specific surface areas, qualitative and quantitative assessments of porosity' and electron micrographs strongly support this structure.

Preparation and characterization of titanium oxynitrides with high specific surface areas

1991 ◽  
Vol 95 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Chae Ho Shin ◽  
Guy Bugli ◽  
Gerald Djega-Mariadassou
Keyword(s):  
Specific Surface ◽  
Surface Areas ◽  
Specific Surface Areas

scholarly journals Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

2018 ◽  
Vol 32 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Jolanta Cieśla ◽  
Zofia Sokołowska ◽  
Barbara Witkowska-Walczak ◽  
Kamil Skic
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Water Vapour ◽  
Specific Surface Area ◽  
Nitrogen Adsorption ◽  
Total Carbon ◽  
Arctic Zone ◽  
Surface Areas ◽  
Arctic Soils ◽  
Specific Surface Areas

AbstractWater vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0−1range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

Synthesis and Characterization of Hydrotalcites: [Zn1−xAlx(OH)2](CO3)x/2·mH2O; x=0.25−0.66

1996 ◽  
Vol 454 ◽  
Author(s):  
M. A. Valenzuela ◽  
E. López-Salinas ◽  
B. Zapata ◽  
J. A. Montoya
Keyword(s):  
Thermal Treatment ◽  
Specific Surface ◽  
Calcination Temperature ◽  
Layered Structure ◽  
Synthesis And Characterization ◽  
Surface Areas ◽  
Constant Ph ◽  
Specific Surface Areas ◽  
Pure Phases

ABSTRACTIn this work a series of [Zn1−xAlx(OH)2](CO3)x/2·mH2O; x=0.25−0.66 were prepared at constant pH in order to study the effect of the thermal treatment on their crystalline srtucture. It was found that is possible to obtain pure Zn-Al hydrotalcite materials within a x = 0.25−0.50 range in comparison with Mg-Al hydrotalcites which yield pure phases in more restricted x ranges (0.25−0.33). All Zn-Al hydrotalcites lost their layered structure at temperatures above 473 K being less stable than their parental Mg-Al hydotalcite (623 K). Specific surface areas of these materials depended strongly on the Zn/Al ratio and calcination temperature, ranging from 280 to 20 m2/g. ZnO and ZnAl2O4 compounds were detected as the calcination products at temperatures higher than 873 K.

scholarly journals Effect of Imposed Shear Strain on Steel Ring Surfaces during Milling in High-Speed Disintegrator

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2234 ◽  
Author(s):  
Karel Dvořák ◽  
Adéla Macháčková ◽  
Simona Ravaszová ◽  
Dominik Gazdič
Keyword(s):  
Specific Surface ◽  
High Speed ◽  
Relative Increase ◽  
Coarse Particles ◽  
Cement Sample ◽  
Surface Areas ◽  
Original Mass ◽  
Specific Surface Areas ◽  
Ground Material

This contribution characterizes the performance of a DESI 11 high-speed disintegrator working on the principle of a pin mill with two opposite counter-rotating rotors. As the ground material, batches of Portland cement featuring 6–7 Mohs scale hardness and containing relatively hard and abrasive compounds with the specific surface areas ranging from 200 to 500 m2/kg, with the step of 50 m2/kg, were used. The character of the ground particles was assessed via scanning electron microscopy and measurement of the absolute/relative increase in their specific surface areas. Detailed characterization of the rotors was performed via recording the thermal imprints, evaluating their wear by 3D optical microscopy, and measuring rotor weight loss after the grinding of constant amounts of cement. The results showed that coarse particles are ground by impacting the front faces of the pins, while finer particles are primarily milled via mutual collisions. Therefore, the coarse particles cause higher abrasion and wear on the rotor pins; after the milling of 20 kg of the 200 m2/kg cement sample, the wear of the rotor reached up to 5% of its original mass and the pins were severely damaged.

scholarly journals Preparation Method of Co3O4Nanoparticles Using Degreasing Cotton and Their Electrochemical Performances in Supercapacitors

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hongyan Xu ◽  
Libo Gao ◽  
Qiang Zhang ◽  
Junyang Li ◽  
Jiangtao Diwu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Specific Surface ◽  
Photoelectron Spectroscopy ◽  
Nitrogen Adsorption ◽  
Electrochemical Performances ◽  
X Ray ◽  
Surface Areas ◽  
Synthetic Strategy ◽  
Different Temperatures ◽  
Specific Surface Areas

Co3O4nanoparticles were fabricated by a novel, facile, and environment-friendly carbon-assisted method using degreasing cotton. Structural and morphological characterizations were performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The component of the sample obtained at different temperatures was measured by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Nitrogen adsorption and desorption isotherms were utilized to reveal the specific surface areas. The formation mechanism of Co3O4nanoparticles was also proposed, demonstrating that the additive degreasing cotton played an indispensable role in the process of synthesizing the sample. The resultant Co3O4sample calcined at 600°C exhibited superior electrochemical performance with better specific capacitance and long-term cycling life, due to its high specific surface areas and pores structures. Additionally, it has been proved that this facile synthetic strategy can be extended to produce other metal oxide materials (e.g., Fe3O4). As a consequence, the carbon-assisted method using degreasing cotton accompanied a promising prospect for practical application.

scholarly journals Assessment of H2O Adsorption Characteristics Based on Zeolite Type

2020 ◽  
Vol 58 (7) ◽  
pp. 501-506
Author(s):  
Kwangbae Kim ◽  
Yesol Lim ◽  
Eunseok kim ◽  
Saera Jin ◽  
Hyunjun Lee ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Inert Gases ◽  
Gas Purification ◽  
Characteristic Analysis ◽  
Adsorption Characteristics ◽  
Surface Areas ◽  
Bet Analysis ◽  
Specific Surface Areas

The properties and H2O adsorption characteristics of two types of zeolites (3A and 13X) with the same shape but different element composition were identified. These zeolites are used in gas purification processes to manufacture 9N ultra-pure inert gases for semiconductor process applications. To analyze the shape and microstructure of the zeolites, an optical microscope and FE-SEM were used. EDS, micro-Raman, and XRD analysis were conducted to analyze their compositions and properties. BET analysis was performed to identify their specific surface areas. Finally, a breakthrough analysis was conducted at room temperature. Based on the results of the optical and microstructure analyses, the cylindrical shaped 3A and 13X were determined to be composed of 2.5-um polyhedrons and 1.4-um massive shapes, respectively. The results of the compositional analysis showed that the main components of both zeolites were Si and Al, whereas K and Na existed in 3A and 13X, respectively. The results of the specific surface area analysis demonstrated that the surface area of 13X was 32 times larger than that of 3A. Specifically, the total specific surface areas were 22.42 and 720.33 m<sup>2</sup>/g for 3A and 13X, respectively. The results of the H2O adsorption characteristic analysis showed that the H2O concentration of 13X was 1.33 times higher than that of 3A. Therefore, with respect to using zeolite for gas purification process applications, 13X might be more suitable to achieve excellent specific surface area and remarkable H2O adsorption.

scholarly journals Textural properties of V2O5/TiO2 catalysts obtained from VOCl3

1985 ◽  
Vol 2 (4) ◽  
pp. 241-251 ◽  
Author(s):  
C. Martin ◽  
V. Rives
Keyword(s):  
Specific Surface ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Monolayer Coverage

V2O5/TiO2 systems have been obtained by reacting TiO2 (P-25 from Degussa, ca 55% anatase, or a rutilised modification, ca 3% anatase) with gaseous VOCl3. The samples have been characterised by X-ray diffraction, UV–Vis spectrophotometry and nitrogen adsorption at 77 K. For the anatase carrier, a monolayer coverage of V2O5 is achieved, but only 0·46 monolayers are formed with the rutilised support. The specific surface areas decrease upon incorporation of V2O5, and that seems to be well dispersed without forming crystallites.

The Formation and Characterization of Poly (p-phenylene benzobisoxazole) Pulps via Stirred Solutions

2015 ◽  
Vol 1120-1121 ◽  
pp. 620-623
Author(s):  
Rong Biao Liu ◽  
Xin Xin Li ◽  
Jun Qian ◽  
Zhe Wen Han
Keyword(s):  
Specific Surface ◽  
Electron Micrographs ◽  
Methanesulfonic Acid ◽  
Scanning Electron Micrographs ◽  
Short Fibers ◽  
Surface Areas ◽  
Stirring Time ◽  
Specific Surface Areas ◽  
Scanning Electron

PBO (p-phenylene benzobisoxazole) short fibers, attached fine fibrils that are called PBO pulp, may precipitate directly from stirred PBO/methanesulfonic acid (MSA) solution by the use of water coagulant in fibrous pulp form. Scanning electron micrographs show that the precipitated PBO pulps have a ribbon-like structure similar to Kevlar pulps. The thermalgravimetric analysis (TGA) show there were no appreciable mass changes until 550 °C in the air. The process yields PBO pulps with different specific surface areas (SSA) depending on the stirring speed, stirring time and the concentration of the PBO/MSA solution. High SSA PBO pulps can be produced by increasing the stirring speed, prolonging the stirring time and reducing the concentration of the PBO/MSA solution.

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