Suggested improvements in the parameters used for describing the low relative pressure region of the water vapour isotherms of activated carbons

Carbon ◽  
2013 ◽  
Vol 60 ◽  
pp. 556-558 ◽  
Author(s):  
Peter Lodewyckx ◽  
Encarnación Raymundo-Piñero ◽  
Miroslava Vaclavikova ◽  
Inna Berezovska ◽  
Matthias Thommes ◽  
...  
Keyword(s):  
Water Vapour ◽  
Activated Carbons ◽  
Relative Pressure ◽  
Pressure Region

scholarly journals Changes in the Adsorption Properties of Activated Carbon due to Partial Oxidation of the Surface

1995 ◽  
Vol 12 (3) ◽  
pp. 211-219 ◽  
Author(s):  
A.M. Youssef ◽  
A.A. El-Khouly ◽  
A.I. Ahmed ◽  
E.I. El-Shafey
Keyword(s):  
Water Vapour ◽  
Surface Coverage ◽  
Activated Carbons ◽  
Textural Properties ◽  
Isosteric Heat ◽  
Adsorption Properties ◽  
Adsorption Of Water ◽  
Oxygen Groups ◽  
Initial Adsorption ◽  
Entropy Of Adsorption

The textural properties (surface area and porosity) of activated carbons change upon treatment with oxidizing solutions. The extent of this change is related to the strength of the oxidizing agent. Oxidation also changes the chemistry of the surface by forming carbon–oxygen groups which are the sites upon which the initial adsorption of water vapour takes place. The adsorption of water vapour at 300–320 K is mainly physical and the isosteric heat of adsorption decreases continuously as the surface coverage increases. The entropy of adsorption of water vapour on untreated and oxidized carbons, at different adsorption temperatures, has been calculated.

scholarly journals Impact on CO2 Uptake of MWCNT after Acid Treatment Study

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Michal Zgrzebnicki ◽  
Nikola Krauze ◽  
Andżelika Gęsikiewicz-Puchalska ◽  
Joanna Kapica-Kozar ◽  
Ewa Piróg ◽  
...  
Keyword(s):  
Greenhouse Effect ◽  
Photoelectron Spectroscopy ◽  
Acid Treatment ◽  
Activated Carbons ◽  
Area Measurement ◽  
Co2 Uptake ◽  
Relative Pressure ◽  
Earth’S Atmosphere ◽  
Average Temperature ◽  
Earth's Atmosphere

Greenhouse effect is responsible for keeping average temperature of Earth’s atmosphere at level of about 288 K. Its intensification leads to warming of our planet and may contribute to adverse changes in the environment. The most important pollution intensifying greenhouse effect is anthropogenic carbon dioxide. This particular gas absorbs secondary infrared radiation, which in the end leads to an increase of average temperature of Earth’s atmosphere. Main source of CO2 is burning of fossil fuels, like oil, natural gas, and coal. Therefore, to reduce its emission, a special CO2 capture and storage technology is required. Carbonaceous materials are promising materials for CO2 sorbents. Thus multiwalled carbon nanotubes, due to the lack of impurities like ash in activated carbons, were chosen as a model material for investigation of acid treatment impact on CO2 uptake. Remarkable 43% enhancement of CO2 sorption capacity was achieved at 273 K and relative pressure of 0.95. Samples were also thoroughly characterized in terms of texture (specific surface area measurement, transmission electron microscope) and chemical composition (X-ray photoelectron spectroscopy).

The importance of outgassing conditions when using water vapour to characterize activated carbons

Carbon ◽  
2019 ◽  
Vol 152 ◽  
pp. 409-415 ◽  
Author(s):  
Leticia F. Velasco ◽  
Anneleen Devos ◽  
Peter Lodewyckx
Keyword(s):  
Water Vapour ◽  
Activated Carbons

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.

A significant enhancement of water vapour uptake at low pressure by amine-functionalization of UiO-67

2015 ◽  
Vol 44 (5) ◽  
pp. 2047-2051 ◽  
Author(s):  
Nakeun Ko ◽  
Jisu Hong ◽  
Siyoung Sung ◽  
Kyle E. Cordova ◽  
Hye Jeong Park ◽  
...  
Keyword(s):  
Water Vapour ◽  
Water Uptake ◽  
Metal Organic Framework ◽  
Significant Enhancement ◽  
Relative Pressure ◽  
Amine Functionalization ◽  
Uptake Capacity ◽  
Water Uptake Capacity ◽  
Metal Organic ◽  
Water Vapour Uptake

The functionalization of the metal–organic framework, UiO-67, with –NH2 groups is proven effective for increasing the water uptake capacity at low relative pressure at 298 K.

scholarly journals A Modified BET Equation for Polylayer Adsorption

1998 ◽  
Vol 16 (4) ◽  
pp. 257-262 ◽  
Author(s):  
B.M. Kats ◽  
V.V. Kutarov
Keyword(s):  
Water Vapour ◽  
Adsorption Isotherms ◽  
Pressure Range ◽  
Cluster Formation ◽  
Relative Pressure ◽  
Bet Theory ◽  
Theory Framework ◽  
Adsorption Systems ◽  
Polylayer Adsorption ◽  
Bet Equation

A three-parameter equation was obtained in the BET theory framework taking into account the correction suggested by the authors. This equation allows the description of adsorption isotherms in the range of polylayer adsorption as well as in the range of cluster formation. This equation was demonstrated as true for a number of adsorption systems in the relative pressure range 0.05 ≤ x ≤ 0.97 for nitrogen, benzene and water vapour.

Water vapour adsorption on lignin-based activated carbons

2007 ◽  
Vol 82 (6) ◽  
pp. 548-557 ◽  
Author(s):  
Jorge Bedia ◽  
José Rodríguez-Mirasol ◽  
Tomás Cordero
Keyword(s):  
Water Vapour ◽  
Activated Carbons ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption

scholarly journals Factors Influencing the Kinetics of Water Vapour Adsorption on Activated Carbons

2021 ◽  
Vol 23 (3) ◽  
pp. 191
Author(s):  
Y. Boutillara ◽  
L. Richelet ◽  
L.F. Velasco ◽  
P. Lodewyckx
Keyword(s):  
Water Vapour ◽  
Activated Carbons ◽  
Kinetic Constant ◽  
Ambient Conditions ◽  
Experimental Conditions ◽  
Adsorption Mechanisms ◽  
Vapour Adsorption ◽  
Water Vapour Adsorption ◽  
The Impact ◽  
Kinetics Of

The performance of porous carbon materials as sorbents is often compromised by the presence of humidity. Studying the kinetics of water vapour adsorption on activated carbons will undeniably help to overcome this issue. This has been approached in this work by evaluating the influence of several operational factors on the dynamic adsorption of water vapour in these materials. Specifically, different carbon types, particle sizes, air flows and ambient conditions (temperature and relative humidity (RH)) were systematically investigated. The impact of each isolated parameter on both the maximum water uptake and the uptake rate was analyzed by fitting the experimental data to the Linear Driving Force (LDF) kinetic model. The results show that except for the particle size, the studied variables play a role in the water sorption kinetics, although to a different extent. It was also confirmed that the LDF model can adequately describe the kinetics of water vapour adsorption independently of the experimental conditions. Finally, the complete water vapour adsorption process can be described by this model, obtaining a different value of the kinetic constant for the sequential stages, involving different adsorption mechanisms.

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