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.

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.

Elimination of Chromium (VI) by Adsorption onto Natural and/or Modified Kaolinite

2018 ◽  
Vol 18 ◽  
pp. 106-112 ◽  
Author(s):  
Nouel Hezil ◽  
Mamoun Fellah ◽  
Omar Assala ◽  
Mohamed Zine Touhami ◽  
Kamel Guerfi
Keyword(s):  
Specific Surface ◽  
Cationic Surfactant ◽  
Interlayer Space ◽  
Nitrogen Adsorption ◽  
Surface Areas ◽  
Chromium Vi ◽  
Two Samples ◽  
Modification Method ◽  
Aqueous Effluents ◽  
Chromate Ion

The purpose of this study is to compare the effectiveness of a natural and / or modified kaolinite to adsorb chromium-containing aqueous effluents in its most toxic form (the hexavalent chromate ion (Cr (VI)). Adsorbant used in the present study is a kaolinite of hydrothermal origin. The modified kaolinite has been prepared by insertion of a cationic surfactant DTAC in interlayer space of this clay. The modification method is generally performed by the cation exchange reaction in the liquid state. The specific surface areas determined by nitrogen adsorption at 77 K for the two samples of kaolinite (natural and modified) are succinctly 48.75 and 63.72 m2/g. Scanning electron microscopy has shown that the used clay is in tubular form. The treatment of natural kaolin by the intercalation of cationic surfactant increased its specific surface of about 18 %. Therefore its power sorptif increased which was found by a comparative study of adsorption of Cr (VI) on natural kaolin and / or modified.

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.

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 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 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.

Acid activation of a Spanish sepiolite: physico-chemical characterization, free silica content and surface area of products obtained

Clay Minerals ◽  
1994 ◽  
Vol 29 (3) ◽  
pp. 361-367 ◽  
Author(s):  
M. A. Vicente Rodriguez ◽  
J. DE D. Lopez Gonzalez ◽  
M. A. Bañares Muñoz
Keyword(s):  
Specific Surface ◽  
Thermal Analyses ◽  
Chemical Characterization ◽  
Nitrogen Adsorption ◽  
Silica Content ◽  
Acid Activation ◽  
Surface Areas ◽  
Free Silica ◽  
Specific Surface Areas ◽  
Sudden Decrease

AbstractA sepiolite from Vallecas (Spain) was treated with solutions of HC1 (1.25, 2.5, 5.0, 10.0 and 20.0 wt%) at 25°C for 2, 6, 24 and 48 h, respectively. The resulting solids were characterized by XRD, FT-IR and thermal analyses, along with SEM, TEM and nitrogen adsorption isotherms at 77 K. The free silica was digested and determined in all samples. Several samples were seen to have specific surface areas up to 450 m2/g, with a maximum value of 549 m2/g in the sample treated with 1.25 wt% HCl for 48 h. A sudden decrease in specific surface areas was observed when free silica was digested.

scholarly journals Adsorption of Aliphatic Alcohols on Yttria-Stabilized Zirconia

2005 ◽  
Vol 23 (2) ◽  
pp. 115-133 ◽  
Author(s):  
I. Faeza ◽  
Mohammad S. Subhani ◽  
Khalil A. Qureshi ◽  
Pervez K. Butt ◽  
A. Riaz
Keyword(s):  
Specific Surface ◽  
Capillary Condensation ◽  
Nitrogen Adsorption ◽  
Yttria Stabilized Zirconia ◽  
Initial Increase ◽  
Relative Pressure ◽  
Stabilized Zirconia ◽  
Surface Areas ◽  
Specific Surface Areas ◽  
Isotherm Equations

Yttria-stabilized zirconia powders with 3, 5, 8 and 10 mol% yttria added (Z3Y, Z5Y, Z8Y and Z10Y, respectively) were prepared. XRD studies indicated that the Z3Y and Z5Y samples were tetragonal whereas Z8Y and Z10Y were found to be cubic in shape. The specific surface areas of the various samples were obtained from nitrogen adsorption isotherms. These showed that as the mol% Y2O3 increased in the samples, an initial increase in surface area occurred up to 5 mol% Y2O3 but thereafter started to decrease. The microporosity of the powders was calculated by applying the Dubinin—Radushkevich (D—R) equation to the data obtained from the nitrogen adsorption studies. D—R plots were found to be linear over the low relative pressure region, followed by an upward deviation at higher relative pressures for all five systems examined. This deviation from linearity corresponded to the existence of a heterogeneous system of micropores, capillary condensation in the transitional pores or multilayer formation on the macropore walls. The adsorption of methanol (MeOH), ethanol (EtOH), n-propanol (PrOH) and n-butanol (BuOH) on pure and yttria-stabilized zirconia was undertaken at temperatures between 273 K and 303 K. The corresponding isotherms obtained were all of type II in the BDDT classification. Specific surface areas were calculated from these isotherms using the Langmuir and BET adsorption isotherm equations and found to be a maximum for the Z5Y powder.

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