scholarly journals Anomalous Isosteric Enthalpy of Adsorption of Methane on Zeolite-Templated Carbon

2013 ◽  
Vol 135 (3) ◽  
pp. 990-993 ◽  
Author(s):  
Nicholas P. Stadie ◽  
Maxwell Murialdo ◽  
Channing C. Ahn ◽  
Brent Fultz
Keyword(s):  
Enthalpy Of Adsorption ◽  
Isosteric Enthalpy Of Adsorption ◽  
Adsorption Of Methane ◽  
Templated Carbon

scholarly journals Isosteric Enthalpy Behavior of CO2 Adsorption on Micro-Mesoporous Materials: Carbon Microfibers (CMFs), SBA-15, and Amine-Functionalized SBA-15

2021 ◽  
Vol 5 (4) ◽  
pp. 102
Author(s):  
Reyna Ojeda-López ◽  
Armando Domínguez-Ortiz ◽  
Carlos Felipe ◽  
A. Cervantes-Uribe ◽  
Isaac J. Pérez-Hermosillo ◽  
...  
Keyword(s):  
Mesoporous Materials ◽  
Mesoporous Material ◽  
Reference Value ◽  
Santa Barbara ◽  
Microporous Material ◽  
Clapeyron Equation ◽  
Enthalpy Of Adsorption ◽  
Amine Functionalized ◽  
Isosteric Enthalpy Of Adsorption ◽  
Carbon Microfibers

The isosteric enthalpy of adsorption (∆adsh ) of CO2 in three different micro and mesoporous materials was evaluated in this work. These materials were a microporous material with functional groups of nitrogen and oxygen (CMFs, carbon microfibers), a mesoporous material with silanol groups (SBA-15, Santa Barbara Amorphous), and a mesoporous material with amine groups (SBA-15_APTES, SBA-15 amine-functionalized with (3-Aminopropyl)-triethoxysilane). The temperature interval explored was between 263 K and 303 K, with a separation of 5 K between each one, so a total of nine CO2 isotherms were obtained. Using the nine isotherms and the Clausius–Clapeyron equation, the reference value for ∆adsh was found. The reference value was compared with those ∆adsh obtained, considering some arrangement of three or five CO2 isotherms. Finally, it was found that at 298 K and 1 bar, the total amount of CO2 adsorbed is 2.32, 0.53, and 1.37 mmol g−1 for CMF, SBA-15, and SBA-15_APTES, respectively. However, at a coverage of 0.38 mmol g−1, ∆adsh is worth 38, 30, and 29 KJ mol−1 for SBA-15_APTES, CMFs, and SBA-15, respectively. So, physisorption predominates in the case of CMF and SBA-15 materials, and the ∆adsh values significantly coincide regardless of whether the isotherms arrangement used was three or five. Meanwhile, in SBA-15_APTES, chemisorption predominates as a consequence of the arrangements used to obtain . This happens in such a way that the use of low temperatures (263–283 K) tends to produce higher ∆adsh values, while the use of high temperatures (283–303 K) decreases the ∆adsh values.

Adsorption Isotherms and Isosteric Enthalpy of Adsorption for Assorted Refrigerants on Activated Carbons

2012 ◽  
Vol 57 (10) ◽  
pp. 2766-2773 ◽  
Author(s):  
Wai Soong Loh ◽  
Azhar Bin Ismail ◽  
Baojuan Xi ◽  
Kim Choon Ng ◽  
Won Gee Chun
Keyword(s):  
Adsorption Isotherms ◽  
Activated Carbons ◽  
Enthalpy Of Adsorption ◽  
Isosteric Enthalpy Of Adsorption

Predicting Neopentane Isosteric Enthalpy of Adsorption at Zero Coverage in MCM-41

Langmuir ◽  
2011 ◽  
Vol 27 (11) ◽  
pp. 6738-6743 ◽  
Author(s):  
Carmelo Herdes ◽  
Carlos Augusto Ferreiro-Rangel ◽  
Tina Düren
Keyword(s):  
Enthalpy Of Adsorption ◽  
Isosteric Enthalpy Of Adsorption ◽  
Mcm 41

Adsorption of Vapours of Some Organic Compounds on Surface of Iron-Substituted Layered Vanadyl Phosphate

2000 ◽  
Vol 65 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Pavel Hradil ◽  
Jiří Votinský ◽  
Karel Komárek ◽  
Vítězslav Zima ◽  
Jaroslava Kalousová ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Organic Molecules ◽  
Ferric Ions ◽  
Vanadyl Phosphate ◽  
Enthalpy Of Adsorption ◽  
Adsorbent Surface ◽  
Specific Retention Volumes ◽  
Specific Retention ◽  
Retention Volumes ◽  
Chromatographic Measurement

Gas chromatographic measurement of specific retention volumes of vapours of selected groups of organic compounds has been used to determine differential molar enthalpy of adsorption of their molecules on the surface of layered vanadyl phosphate substituted with ferric ions having the composition of [Fe(H2O)]0.20(VO)0.80PO4. Various types of bonds of the molecules to the surface of the layered adsorbent including their probable orientation with respect to the layers have been discussed. It was observed a dependence of the specific peak elution volume and shape of chromatographic peak on the sample size in the cases of those compounds whose molecules are chemically bound to the adsorbent surface. A connection is pointed out between the adsorption strength of the organic molecules on the layered adsorbent and the tendency of the system to undergo intercalation reaction.

scholarly journals Clay-Based Affinity Probes for Selective Cleanup and Determination of Aflatoxin B1 Using Nanostructured Montmorillonite on Quartz

2003 ◽  
Vol 86 (3) ◽  
pp. 534-539 ◽  
Author(s):  
Henry J Huebner ◽  
Timothy D Phillips
Keyword(s):  
Aflatoxin B1 ◽  
Composite Media ◽  
Enthalpy Of Adsorption ◽  
Composite Columns ◽  
High Affinity ◽  
Composite Adsorbents ◽  
Immunoaffinity Columns ◽  
Affinity Probes ◽  
Linear Trends

Abstract A study was conducted to investigate the selective cleanup and determination of aflatoxin B1 (AfB1) from contaminated media. Composite adsorbents were formulated from calcium montmorillonite clay, which possesses a high affinity and enthalpy of adsorption for AfB1. Nanostructuring techniques were used to construct various formulations of the clay-based composite media. In AfB1 adsorption studies with prototypical affinity columns, these composites offered narrowly defined, reproducible capacity ranges. Composite recoveries of AfB1 from spiked grains exhibited linear trends that correlated well with the range of spike levels. Composite columns provided lower recoveries of AfB1 from naturally contaminated corn than did immunoaffinity columns; however, recoveries were consistent and purified extracts were free of inter-fering compounds, as determined by liquid chro-matography with fluorescence detection.

The adsorption of lower trialkylphosphates at the dodecane – water interface

1980 ◽  
Vol 58 (24) ◽  
pp. 2789-2795 ◽  
Author(s):  
Norman H. Sagert ◽  
Woon Lee
Keyword(s):  
Equation Of State ◽  
Chain Length ◽  
Water Interface ◽  
Two Dimensional ◽  
Free Energies ◽  
Dimensional Solution ◽  
Interfacial Tensions ◽  
Enthalpy Of Adsorption ◽  
Solution Models ◽  
Methylene Group

The adsorption of tripropylphosphate, triethylphosphate, and trimethylphosphate at the dodecane–water interface has been studied at temperatures from 293 to 313 K. Standard free energies of adsorption were obtained from the lowering of interfacial tensions in the low (< 10−4) solute mole fraction region. Standard enthalpies and entropies of adsorption were then obtained from the temperature variation of the standard free energies of adsorption.Standard free energies of adsorption from dodecane showed little variation with solute chain length, with the exception of trimethylphosphate. On the other hand, free energies of adsorption from water decreased by 3.45 kJ/mol for each methylene group added, again with the exception of trimethylphosphate. Enthalpies of adsorption increased linearly with increasing solute chain length for adsorption from either phase. For each methylene group added, the enthalpy of adsorption from dodecane increased by 2.9 kJ/mol, while that from water increased by 2.4 kJ/mol.Results for tripropylphosphate adsorption and for triethylphosphate adsorption at higher temperatures could be adequately described by the Schofield–Rideal equation of state, but not by simple two-dimensional solution models. Results for trimethylphosphate adsorption and for triethylphosphate adsorption at lower temperatures could not be fitted adequately by either type of equation of state.

Experimental Study on Adsorption of Carbon Dioxide on 13X Molecular Sieve for Coolant Helium Purification

2013 ◽  
Author(s):  
Hua Chang ◽  
Tao Ma ◽  
Ling Liu ◽  
Hua-Qiang Yin ◽  
Xue-Dong He
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Capacity ◽  
Molecular Sieve ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Carbon Dioxide Partial Pressure ◽  
Zone Model ◽  
Low Carbon ◽  
Enthalpy Of Adsorption ◽  
Operation Conditions

The adsorption capability of carbon dioxide on 13X molecular sieve (13XMS) was investigated in a fixed-bed apparatus with two-road gas mixing system by dynamic column breakthrough method with helium as carrier gas at helium purification conditions of high-temperature gas-cooled reactor (HTGR). Experiments were performed at temperatures of 5°C ∼35 °C and low carbon dioxide partial pressure range of 10∼150Pa. By analyzing the breakthrough curve, both equilibrium adsorption capacity and kinetic adsorption capacity at breakthrough point were determined. Based on mass-transfer zone model, the experimental breakthrough curves at different operation conditions were analyzed. The carbon dioxide isotherm on 13XMS was fitted well by Langmuir model and the enthalpy of adsorption of carbon dioxide was estimated.

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