scholarly journals Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
V. Garcia-Cuello ◽  
J. C. Moreno-Piraján ◽  
L. Giraldo-Gutiérrez ◽  
K. Sapag ◽  
G. Zgrablich
Keyword(s):  
Stainless Steel ◽  
Adsorption Isotherms ◽  
Heat Conducting ◽  
Differential Heat ◽  
Adsorption Calorimetry ◽  
Differential Enthalpy ◽  
Type Zeolite ◽  
Differential Heat Of Adsorption ◽  
Commercial Equipment

An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsorption microcalorimeter is used to obtain adsorption isotherms and the corresponding differential heats for the adsorption of CO2 on a reference solid, such as a NaZSM-5 type zeolite. Results for the behavior of this system are compared with those obtained with commercial equipment and with other studies in the literature.

Moisture adsorption thermodynamics of wood from fractal-geometry approach

Holzforschung ◽  
2004 ◽  
Vol 58 (3) ◽  
pp. 274-279 ◽  
Author(s):  
J. Cao ◽  
D.P. Kamdem
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Adsorption Isotherms ◽  
Fractal Geometry ◽  
Moisture Sorption ◽  
Fractal Dimensions ◽  
Future Research ◽  
Differential Heat ◽  
Internal Surfaces ◽  
Differential Heat Of Adsorption

Abstract The fractal-geometry approach was used to calculate the thermodynamic properties of moisture sorption by wood from the adsorption isotherms in this study. The results were compared with those from an isosteric approach and a calorimetric approach. The adsorption isotherms of Southern yellow pine (Pinus spp.) were measured at 4, 15, 30, and 40°C to provide source data for the calculation of both fractal-geometry and isosteric approaches. The results show that the fractal dimensions of the internal surfaces of wood vary between 2.4 and 2.5. The curves of the differential heat of adsorption −∆H against moisture content from the fractal-geometry approach are similar to those from calorimetric measurements in previous research. The −∆H values from the isosteric approach increased with moisture content within a moisture content range up to 3%. And, at moisture contents higher than 3%, the −∆H values from this method are much higher than those from the fractal-geometry approach and calorimetric approach. As a result, the fractal-geometry approach is applicable to calculate the differential thermodynamic properties of moisture sorption by wood in future research.

Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

2011 ◽  
pp. 133-139
Author(s):  
V Garcia-Cuello ◽  
J Moreno-Piraján ◽  
L Giraldo-Gutierrez ◽  
K Sapag ◽  
G Zgrablich
Keyword(s):  
Adsorption Calorimetry ◽  
Differential Enthalpy

scholarly journals Adsorption of Carbon Dioxide on Mesoporous Silicas near the Critical Temperature

2005 ◽  
Vol 23 (9) ◽  
pp. 763-776 ◽  
Author(s):  
Narihito Tatsuda ◽  
Yasutomo Goto ◽  
Norihiko Setoyama ◽  
Yoshiaki Fukushima
Keyword(s):  
Carbon Dioxide ◽  
Critical Temperature ◽  
Adsorption Isotherms ◽  
Capillary Condensation ◽  
Mesoporous Silicas ◽  
Unit Surface Area ◽  
Slab Model ◽  
Inverse Slope ◽  
Differential Heat ◽  
Differential Heat Of Adsorption

The adsorption of carbon dioxide on mesoporous silicas was studied near the critical temperature (Tc) of CO2, i.e. 304.2 K. The critical temperature in the mesopores at which the first-order phase transition (capillary condensation) was observed (Tcp) was estimated from the inverse slope of the adsorption isotherms and the behaviour of the adsorption isotherms per unit surface area. The values of Tcp for CO2 in mesopores whose radii, rp, were 3.02 and 2.14 nm were higher than those estimated using a slab model in which the adsorbing parts of layer were clearly separated from the non-adsorbing regions. The differential heat of adsorption decreased with increasing pore size of the mesoporous adsorbent. This result also suggested a deviation from the slab model.

Determination of the degree of adsorption and the heat of adsorption for 1-butylamine and ammonia on NaHY zeolites

1984 ◽  
Vol 49 (12) ◽  
pp. 2739-2743 ◽  
Author(s):  
Miloslav Křivánek ◽  
Pavel Jírů
Keyword(s):  
Lewis Acid ◽  
Adsorption Isotherms ◽  
Heat Of Adsorption ◽  
Brønsted And Lewis Acid

The degree and heat of adsorption of 1-butylamine and ammonia were measured on samples of NaHY zeolites activated at 400-600°C. The adsorption isotherms and calorimetric curves were compared for the two bases, and the amount of Bronsted and Lewis acid centres was determined from the calorimetric curves.

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