THE PORE STRUCTURE AND ADSORPTIVE PROPERTIES OF SOME ACTIVATED CHARCOALS: I. THE ADSORPTION OF WATER VAPOUR AND ITS DEPENDENCE ON PORE SIZE

1946 ◽  
Vol 24b (4) ◽  
pp. 109-123 ◽  
Author(s):  
M. N. Fineman ◽  
R. M. Guest ◽  
R. McIntosh
Keyword(s):  
Adsorption Isotherm ◽  
Water Vapour ◽  
Pore Volume ◽  
Water Adsorption ◽  
Capillary Condensation ◽  
Total Pore Volume ◽  
Relative Pressure ◽  
Surface Areas ◽  
Adsorption Of Water ◽  
Adsorptive Properties

An examination of the influence of the structure of charcoal adsorbents on the form of the water adsorption isotherm has been attempted by determinations of (1) surface areas of a series of charcoals of varying degrees of activation using nitrogen and butane as adsorbates; (2) total pore volume of each adsorbent sample by density measurements in helium and in mercury; (3) density of adsorbents when immersed in water; (4) adsorption isotherms for water vapour; and (5) surface areas of charcoals partly saturated with water vapour.The evidence appears to suggest that certain very small and certain very large voids in charcoal are not occupied by water vapour at any value of the relative pressure. The former, 10% by volume, are important in terms of surface area; the latter, 30% by volume, influence pore volume calculations. An explanation of the shape of the water adsorption isotherm is attempted in the light of these facts. Estimates of the submicro, micro, and macro pore sizes show fair agreement when these are based upon either the capillary condensation theory or measurements of the total area and volume of the charcoal pores.

scholarly journals Some Surface Properties of Activated Carbons Prepared by Gasification with Different Gases

1997 ◽  
Vol 15 (9) ◽  
pp. 707-715 ◽  
Author(s):  
Amina A. Attia
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
Water Vapour ◽  
Pore Volume ◽  
Activated Carbons ◽  
Total Pore Volume ◽  
Surface Areas ◽  
Adsorption Of Nitrogen ◽  
Adsorption Of Water ◽  
Different Gases

A non-activated carbon ‘D’ was obtained by carbonizing date pits at 773 K in a limited supply of air. Activated carbons were obtained by gasifying portions of ‘D’ with air at 773 K, carbon dioxide at 1123 K, or steam at 1173 K, all to different burn-offs between 15% and 60%. The adsorption of nitrogen at 77 K and of carbon dioxide at 298 K was investigated using a volumetric adsorption apparatus of a conventional type. The adsorption of water vapour at 298 K and the chemisorption of pyridine at 423 K was followed by means of quartz spring balances. Gasification with oxidizing gases increased the surface area and total pore volume, as measured by nitrogen or carbon dioxide adsorption. In most cases, comparable surface areas were measured by nitrogen and carbon dioxide. The adsorption of water vapour depended on the percentage burn-off and the gasification conditions. Chemisorption of pyridine at 423 K was found to be related to the chemistry of the surface rather than to the surface area or total pore volume.

Physical adsorption of gases on porous solids. I. Comparison of loose powders and porous plugs

1951 ◽  
Vol 209 (1096) ◽  
pp. 59-69 ◽  
Keyword(s):  
Pore Volume ◽  
Capillary Condensation ◽  
Physical Adsorption ◽  
Particle Surface ◽  
Total Pore Volume ◽  
Internal Surface ◽  
Porous Solids ◽  
Porous Plug ◽  
Surface Areas ◽  
Total Particle

For the first time, comparison has been made of adsorption on a given surface both as a free surface and as the internal surface of a porous plug. In this way it has been possible to provide direct evidence both for capillary condensation and for blockage of capillaries with adsorbed layers in porous solids. Blockage produced well-marked effects only where the surface was of the order of 1000 m. 2 /g. and the porosity was less than 0·6. Where it was observed, it was to be noted that (i) molecules tended to be attracted into blocked capillaries, producing swelling, (ii) monolayer capacities and hence surface areas determined by the B. E. T. method were values which corresponded only to the unblocked surface area when the monolayer is nearly complete. At the low-pressure end of adsorption isotherms, plug and powder gave identical results within the limits of experimental error, i. e. better than 1%, so that, until blockage or capillary condensation was manifested, the total particle surface was accessible to adsorption. In agreement with this, the total pore volume was also accessible, since the volume adsorbed at saturation was not less than the pore volume.

scholarly journals Microporous Materials Based on Norbornadiene-Based Cross-Linked Polymers

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1382 ◽  
Author(s):  
Dmitry Alentiev ◽  
Dariya Dzhaparidze ◽  
Natalia Gavrilova ◽  
Victor Shantarovich ◽  
Elena Kiseleva ◽  
...  
Keyword(s):  
Pore Volume ◽  
Total Pore Volume ◽  
Amorphous Polymers ◽  
Co2 Uptake ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Pd Catalysts ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Surface Areas

New microporous homopolymers were readily prepared from norbornadiene-2,5, its dimer and trimer by addition (vinyl) polymerization of the corresponding monomers with 60–98% yields. As a catalyst Pd-N-heterocyclic carbene complex or Ni(II) 2-ethylhexanoate activated with Na+[B(3,5-(CF3)2C6H3)4]− or methylaluminoxane was used. The synthesized polynorbornenes are cross-linked and insoluble. They are glassy and amorphous polymers. Depending on the nature of the catalyst applied, BET surface areas were in the range of 420–970 m2/g. The polymers with the highest surface area were obtained in the presence of Pd-catalysts from the trimer of norbornadiene-2,5. The total pore volume of the polymers varies from 0.39 to 0.79 cm3/g, while the true volume of micropores was 0.14–0.16 cm3/g according to t-plot. These polymers gave CO2 uptake from 1.2 to 1.9 mmol/g at 273 K and 1 atm. The porous structure of new polymers was also studied by means of wide-angle X-ray diffraction and positron annihilation lifetime spectroscopy.

XI.—The Adsorption of Sulphur Dioxide by Charcoal at –10° C

1918 ◽  
Vol 37 ◽  
pp. 161-172 ◽  
Author(s):  
A. M. Williams
Keyword(s):  
Adsorption Isotherm ◽  
Water Vapour ◽  
Sulphur Dioxide ◽  
Heat Of Adsorption ◽  
Constant Volume ◽  
Vapour Adsorption ◽  
Adsorption Of Water ◽  
University College London ◽  
Tentative Explanation ◽  
Adsorption Curve

SUMMARY(1) The adsorption of sulphur dioxide by blood charcoal at –10° C. was studied, and measurements were taken of the amount adsorbed, the pressure, and the isothermal heat of adsorption at constant volume.(2) The adsorption isotherm is a typical vapour adsorption curve, and runs the same course as that found by Trouton for the adsorption of water vapour.(3) The heat of adsorption curve passes through a minimum and a maximum, and finally runs parallel to the adsorption axis. A tentative explanation of this is offered.In conclusion, the author would seek to express his thanks to Professor F. G. Donnán, F.R.S., for his advice given in the course of these experiments which were performed in 1913–14 in the Chemical Laboratories, University College, London.

scholarly journals On mineral dust aerosol hygroscopicity

2020 ◽  
Author(s):  
Lanxiadi Chen ◽  
Chao Peng ◽  
Athanasios Nenes ◽  
Wenjun Gu ◽  
Hanjing Fu ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
Relative Humidity ◽  
Water Adsorption ◽  
Mineral Dust ◽  
Adsorbed Water ◽  
Dust Aerosol ◽  
Sample Mass ◽  
Surface Areas ◽  
The World ◽  
Aerosol Hygroscopicity

Abstract. Despite its importance, hygroscopicity of mineral dust aerosol remains highly uncertain. In this work, we investigated water adsorption and hygroscopicity of different mineral dust samples at 25 °C, via measuring sample mass at different relative humidity (RH, up to 90 %) using a very sensitive balance. Mineral dust samples examined (twenty one in total) included seven authentic mineral dust samples from different regions in the world and fourteen major minerals contained in mineral dust aerosol. At 90 % RH, mass ratios of adsorbed water to the dry mineral ranged from 0.0011 to 0.3080, largely depending on the BET surface areas of mineral dust samples. The surface coverages of adsorbed water were determined to vary between 1.26 and 8.63 at 90 % RH, and it was found that the Frenkel-Halsey-Hill (FHH) adsorption isotherm could well describe surface coverages of adsorbed water as a function of RH, with AFHH and BFHH parameters in the range of 0.15–4.39 and 1.10–1.91, respectively. The comprehensive and robust data obtained would largely improve our knowledge of hygroscopicity of mineral dust aerosol.

scholarly journals On mineral dust aerosol hygroscopicity

2020 ◽  
Vol 20 (21) ◽  
pp. 13611-13626
Author(s):  
Lanxiadi Chen ◽  
Chao Peng ◽  
Wenjun Gu ◽  
Hanjing Fu ◽  
Xing Jian ◽  
...  
Keyword(s):  
Adsorption Isotherm ◽  
Water Adsorption ◽  
Mineral Dust ◽  
Adsorbed Water ◽  
Dust Aerosol ◽  
Vapor Sorption ◽  
Surface Areas ◽  
The World ◽  
Aerosol Hygroscopicity ◽  
Fractional Surface

Abstract. Despite its importance, hygroscopicity of mineral dust aerosol remains highly uncertain. In this work, we investigated water adsorption and hygroscopicity of different mineral dust samples at 25 ∘C, via measurement of sample mass at different relative humidity (RH, up to 90 %) using a vapor sorption analyzer. Mineral dust samples examined (21 in total) included seven authentic mineral dust samples from different regions in the world and 14 major minerals contained in mineral dust aerosol. At 90 % RH, the mass ratios of adsorbed water to the dry mineral ranged from 0.0011 to 0.3080, largely depending on the BET surface areas of mineral dust samples. The fractional surface coverages of adsorbed water were determined to vary between 1.26 and 8.63 at 90 % RH, and it was found that the Frenkel–Halsey–Hill (FHH) adsorption isotherm could describe surface coverages of adsorbed water as a function of RH well, with AFHH and BFHH parameters in the range of 0.15–4.39 and 1.10–1.91, respectively. The comprehensive and robust data obtained would largely improve our knowledge of hygroscopicity of mineral dust aerosol.

scholarly journals Interaction of Ethanol Vapour with Silane-Modified Surface of Corning Porous Glass CPG-10

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Misael Silas Nadiye-Tabbiruka
Keyword(s):  
Adsorption Isotherm ◽  
Porous Glass ◽  
Capillary Condensation ◽  
Type Ii ◽  
Ethanol Vapour ◽  
Surface Areas ◽  
Type Iv ◽  
Similar Dependence ◽  
Modified Surface ◽  
Ethanol Adsorption

The interaction of ethanol vapour at 293 K with modified Corning controlled porous glass (CPG-10) samples of various pre-silylation is reported. Ethanol adsorption on CPG-10 was greatly reduced by silylation to extents largely depending on the silylation extent, type of silane used, and on the concentration and accessibility of residual silanols. The obtained adsorption isotherms, BET surface areas, as well as the observed changes at the various stages during the sorption particularly in the capillary condensation region also showed similar dependence. In the capillary condensation region, in the case of the dimethyl dichlorosilane-modified sample, hysteresis type was changed from H3 to H1. On the triethyl chlorosilane-modified sample an unexpected suppression of hysteresis effects occurred with a consequent transformation of type IV to type II adsorption isotherm.

Adsorption of Water as a Means to Remove Bulk Metastability of CsHSO4 and RbH2PO4

1987 ◽  
Vol 42 (6) ◽  
pp. 565-571 ◽  
Author(s):  
Bogdan Baranowski ◽  
Milan Friesel ◽  
Arnold Lundén
Keyword(s):  
Phase Transitions ◽  
Water Vapour ◽  
Vapour Pressure ◽  
Water Adsorption ◽  
Surface Adsorption ◽  
Stable State ◽  
Solid Matrix ◽  
Water Vapour Pressure ◽  
Scanning Calorimetry ◽  
Adsorption Of Water

Differential scanning calorimetry (DSC) and thermogravimetry (TG) are applied to study the conditions required for CsHSO4 and RbH2PO4 to undergo phase transitions at 333 ± 1 K and 352 ± 3 K, respectively. It is demonstrated that water adsorption on the surface of metastable polycrystalline samples triggers their transition to the stable state. It is further shown that the transition of CsHSO4 only occurs if the water vapour pressure is sufficiently high. If the sample is prepared at 293 K this threshold is 6.3 ± 0.7 mm Hg. A correlation is found between the transition temperature and the water vapour pressure. While it has been reported recently that adsorbed molecules can cause phase transitions in the surface layer of a solid matrix, our results are the first well-established examples of a direct correlation between surface adsorption and bulk phenomena. There is a relation to an early idea of Schwab.

On mineral dust hygroscopicity

2021 ◽  
Author(s):  
Mingjin Tang ◽  
Lanxiadi Chen ◽  
Chao Peng ◽  
Wenjun Gu
Keyword(s):  
Adsorption Isotherm ◽  
Relative Humidity ◽  
Water Adsorption ◽  
Mineral Dust ◽  
Adsorbed Water ◽  
Dust Aerosol ◽  
Vapor Sorption ◽  
Surface Areas ◽  
The World ◽  
Fractional Surface

<p>Despite its importance, hygroscopicity of mineral dust aerosol remains highly uncertain. In this work, we investigated water adsorption and hygroscopicity of different mineral dust samples at 25 ∘C, via measurement of sample mass at different relative humidity (RH, up to 90 %) using a vapor sorption analyzer. Mineral dust samples examined (21 in total) included seven authentic mineral dust samples from different regions in the world and 14 major minerals contained in mineral dust aerosol. At 90 % RH, the mass ratios of adsorbed water to the dry mineral ranged from 0.0011 to 0.3080, largely depending on the BET surface areas of mineral dust samples. The fractional surface coverages of adsorbed water were determined to vary between 1.26 and 8.63 at 90 % RH, and it was found that the Frenkel–Halsey–Hill (FHH) adsorption isotherm could describe surface coverages of adsorbed water as a function of RH well, with AFHH and BFHH parameters in the range of 0.15–4.39 and 1.10–1.91, respectively. The comprehensive and robust data obtained would largely improve our knowledge of hygroscopicity of mineral dust aerosol.</p>

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