Determination of the surface area of single particles from high-pressure carbon dioxide adsorption-desorption measurements in an electrodynamic chamber

1991 ◽  
Vol 5 (1) ◽  
pp. 227-228 ◽  
Author(s):  
Ezra Bar-Ziv ◽  
John P. Longwell ◽  
Adel F. Sarofim
2015 ◽  
Vol 36 (4) ◽  
pp. 3-6 ◽  
Author(s):  
Ewa Koszela-Marek

Abstract The paper presents the results of laboratory studies of the 200 MPa pressure effect on specific surface area of clay. The original high-pressure investigation stand was used for the pressure tests. Determination of the specific surface area was performed by the methylene blue adsorption method. The results of the specific surface area test were compared for non-pressurized clays and for clays pressured in a high-pressure chamber. It was found that the specific surface area of pressurized soil clearly increased. This shows that some microstructural changes take place in the soil skeleton of clays.


Author(s):  
Nikolay I. Kol'tsov ◽  
Vladislav Kh. Fedotov

Investigation of the regularities of chemical processes, not only near but also far from the stationary state, gives additional information on their mechanisms. In this paper, we present a new method for estimating rate constants of adsorption-desorption processes from the experimentally measured values of the nonstationary concentrations of an adsorbed substance, based on calculating the instantaneous rates of the adsorption (or desorption) process. This method allows to connect unknown kinetic parameters of adsorption (desorption) of a substance on the catalyst surface for various most probable assumed mechanisms with the calculated values of the instantaneous rates of adsorption-desorption processes. As a consequence, the method makes it possible to solve two types of inverse problems of chemical kinetics: calculate point and interval values of rates constants of adsorption and desorption; determine the most likely mechanism from several proposed mechanisms of implementation of these processes. Using this method, point and interval values of the rates constants of adsorption and desorption of carbon dioxide were determined on the base of nonstationary experimental data on adsorption on the assumption of carbon dioxide adsorption on a chromoxide catalyst to three proposed mechanisms: linear, bimolecular and dissociative. Based on the results of calculations, the corresponding non-stationary dependences of carbon dioxide adsorption were restored, which were compared with the experimental data. The obtained results confirm that the previously established dissociative mechanism of adsorption of carbon dioxide on the chromoside catalyst is the most probable. The developed simple method does not require the use of complex optimization calculations and can be used to solve the inverse problem of chemical kinetics associated with the determination of mechanisms and the estimation of the rates constants of adsorption and desorption of substances on various catalysts.Forcitation:Kol’tsov N.I., Fedotov V.Kh. Study of carbon dioxide adsorption on chromoxide catalyst on non-stationary concentrations. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 37-42


2014 ◽  
Vol 1049-1050 ◽  
pp. 101-104 ◽  
Author(s):  
De Zhu Cheng ◽  
Ai Ling Du ◽  
Ai Qin Du

Methane and carbon dioxide of different pressures were absorbed by the anthracite coal for 5 hours in high pressure reactor. When adsorption experiment was completed, pressure is reduced quickly. The content of pulverized coal which was produced by releasing gas quickly, was used to reflect capacity of gas adsorption. The result showed that the content of pulverized coal which was produced by adsorbing CH4 was higher than that was produced by adsorbing CO2 on the same coal under the same pressure. Langmuir isotherm and Freundlich isothermal can describe coal methane adsorption. Freundlich isothermal can be a good description of coal carbon dioxide adsorption.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2361 ◽  
Author(s):  
Xuyan Song ◽  
Jialin Yu ◽  
Min Wei ◽  
Ran Li ◽  
Xi Pan ◽  
...  

Ionic-liquid-functionalized zeolitic imidazolate frameworks (ZIF) were synthesized using the co-ligands of 2-methylimidazole and amine-functionalized ionic liquid during the formation process of frameworks. The resulting ionic-liquid-modified ZIF had a specific surface area of 1707 m2·g−1 with an average pore size of about 1.53 nm. Benefiting from the large surface area and the high solubility of carbon dioxide in ionic-liquid moieties, the synthesized materials exhibited a carbon dioxide adsorption capacity of about 24.9 cm3·g−1, whereas it was 16.3 cm3·g−1 for pristine ZIF at 25 °C under 800 mmHg. The results demonstrate that the modification of porous materials with ionic liquids could be an effective way to fabricate solid sorbents for carbon dioxide adsorption.


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