THERMODYNAMIC PROPERTIES OF HYDROCARBONS ADSORBED ON RUTILE II

1955 ◽  
Vol 33 (2) ◽  
pp. 259-267 ◽  
Author(s):  
H. P. Schreiber ◽  
R. McIntosh
Keyword(s):  
Thermodynamic Properties ◽  
Heat Of Adsorption ◽  
The State ◽  
Molar Entropy ◽  
Adsorption Sites ◽  
Adsorbed Methane ◽  
Entropy Of Adsorption ◽  
Adsorption Curve ◽  
Adsorption Of Methane

Integral molar heats and entropies of adsorbed methane and propane on rutile have been computed from data of isotherms at 103.2 ° and 110.2°K. for methane and 166.3° and 224.6°K. for propane. Some resemblance has been found between these functions and those for argon, nitrogen, and oxygen adsorbed on rutile, reported by Drain and Morrison. The integral molar entropy of adsorption made possible a test of the model of a localized film without interactions on a heterogeneous substrate. The model was found to be a reasonable representation of the state of adsorbed methane up to about 0.5 of the monolayer and of propane up to about 0.3 of the monolayer. A unique heat of adsorption curve for the adsorption of methane, ethane, propane, and n-butane has been derived and its significance is briefly discussed. The curve has been employed to derive functions for the distribution of energies among the adsorption sites of the substrate.

scholarly journals The adsorption of vapours on mercury. II. The entropy and heat of adsorption of non-polar substances

1946 ◽  
Vol 187 (1008) ◽  
pp. 73-87 ◽  
Keyword(s):  
Heat Of Adsorption ◽  
Attractive Potential ◽  
Intermolecular Distance ◽  
The Third ◽  
Striking Result ◽  
Surface Mobility ◽  
Repulsive Potentials ◽  
Benzene Toluene ◽  
Entropy Of Adsorption ◽  
Rotational Freedom

An attempt has been made to interpret the entropy of adsorption of benzene, toluene and n -heptane on mercury. These investigations have indicated with fair accuracy the amount of translational and rotational freedom possessed by the substances on the surface of mercury. The most striking result was obtained with benzene, where by denying all rotation except in the plane of the ring and denying the third degree of translational freedom, the calculated entropy of adsorption agreed closely with the experimental value. The surface mobility of toluene was found to be considerably hindered, and the entropy of adsorption of n -heptane confirmed the view that the molecules were partially rolled up. An attempt has been made to derive the theoretical heat of adsorption of benzene from various relations for the attractive and repulsive potentials for the van der Waals forces near a metal surface. The values obtained were of the same magnitude as the experimental value. The calculations gave some evidence of the ranges of intermolecular distance over which the different equations for the attractive potential were accurate.

scholarly journals Adsorption Equilibrium of 1, 1-Dichloro-1-fluoroethane (HCFC-141b) on a Hydrophobic Zeolite

1998 ◽  
Vol 16 (2) ◽  
pp. 67-75 ◽  
Author(s):  
Wen-Tien Tsai ◽  
Ching-Yuan Chang ◽  
Chih-Yin Ho
Keyword(s):  
Experimental Data ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Adsorption Isotherms ◽  
Ozone Depletion ◽  
Adsorption Equilibrium ◽  
Stratospheric Ozone ◽  
Stratospheric Ozone Depletion ◽  
Equilibrium Isotherms ◽  
Entropy Of Adsorption

Of the major replacements for chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) are now accepted as being prime contributors to stratospheric ozone depletion. As a consequence, the development of adsorbents capable of adsorbing and recovering specific HCFCs has received great attention. This paper describes an investigation of the adsorption equilibrium of 1, 1-dichloro-1-fluoroethane (HCFC-141b) vapour on a commercial hydrophobic zeolite. The corresponding Henry, Freundlich and Dubinin–Radushkevich (D–R) equilibrium isotherms have been determined and found to correlate well with the experimental data. Based on the Henry adsorption isotherms obtained at 283, 303 and 313 K. thermodynamic properties such as the enthalpy, free energy and entropy of adsorption have been computed for the adsorption of HCFC-141b vapour on the adsorbent. The results obtained could be useful in the application of HCFC adsorption on the hydrophobic zeolite studied.

Comparison of the Two Methods to Determine State Parameters of Wet Saturated Steam

2014 ◽  
Vol 904 ◽  
pp. 330-334
Author(s):  
Ya Rong Wang ◽  
Pei Rong Wang
Keyword(s):  
Thermodynamic Properties ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
The State ◽  
Saturated Steam ◽  
Steam Turbines ◽  
Water Steam ◽  
Working Medium

Water steam is widely used in steam turbines, steam engines, nuclear power plants and many other places. As a kind of working medium, it has many advantages, such as proper thermodynamic properties, non-toxic, odorless ,cheap, and so on. So it is very important how to determine the state parameters of water steam. In this paper we describe the two methods to determine state parameters of wet saturated steam, and the two methods are compared.

scholarly journals Thermodynamics of Chemical and Electrochemical Stability of Fe – Ge System Alloys

2019 ◽  
Author(s):  
Aleksandr Georgievich Tyurin ◽  
Pavel Anatolyevich Nikolaychuk ◽  
Irina Igorevna Kanatyeva
Keyword(s):  
Thermodynamic Properties ◽  
Electrochemical Behaviour ◽  
State Diagram ◽  
Electrochemical Stability ◽  
The State ◽  
Gibbs Energies

The standard Gibbs energies of formation of intermatallides Fe<sub>6</sub>Ge<sub>5</sub>, FeGe, FeGe<sub>2</sub> were estimated. Thermodynamic properties of α- and β- solid metallic solutions of Fe – Ge system and spinel solutions of Fe<sub>3</sub>O<sub>4</sub> – Fe<sub>2</sub>GeO<sub>4</sub> system were determined. The state diagram of Fe – Ge – O system and the potential – рН diagram of Fe – Ge – H<sub>2</sub>O system at 25ºС were plotted. The thermodynamic features of the corrosion-electrochemical behaviour of Fe – Ge system was discussed

scholarly journals IGE Model: An Extension of the Ideal Gas Model to Include Chemical Composition as Part of the Equilibrium State

2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Christopher P. Paolini ◽  
Subrata Bhattacharjee
Keyword(s):  
Thermodynamic Properties ◽  
Equilibrium State ◽  
Major Change ◽  
Equilibrium Composition ◽  
Ideal Gas ◽  
The State ◽  
State Evaluation ◽  
Pure Substances ◽  
Ideal Gas Model ◽  
The Ideal

The ideal gas (IG) model is probably the most well-known gas models in engineering thermodynamics. In this paper, we extend the IG model into an ideal gas equilibrium (IGE model) mixture model by incorporating chemical equilibrium calculations as part of the state evaluation. Through a simple graphical interface, users can set the atomic composition of a gas mixture. We have integrated this model into a thermodynamic web portal TEST (http://thermofluids.sdsu.edu/) that contains Java applets for various models for properties of pure substances. In the state panel of the IGE model, the known thermodynamic properties are entered. For a given pressure and temperature, the mixture's Gibbs function is minimized subject to atomic constraints and the equilibrium composition along with thermodynamic properties of the mixture are calculated and displayed. What is unique about this approach is that equilibrium computations are performed in the background, without requiring any major change in the familiar user interface used in other state daemons. Properties calculated by this equilibrium state daemon are compared with results from other established applications such as NASA CEA and STANJAN. Also, two different algorithms, an iterative approach and a direct approach based on minimizing different thermodynamic functions in different situation, are compared.

scholarly journals Kinetics of water sorption of damaged bean grains: Thermodynamic properties

2017 ◽  
Vol 21 (8) ◽  
pp. 556-561 ◽  
Author(s):  
Paulo C. Corrêa ◽  
Fernanda M. Baptestini ◽  
Jaime D. B. Vanegas ◽  
Rafael Leite ◽  
Fernando M. Botelho ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Adsorption Process ◽  
Initial Moisture Content ◽  
Mechanical Damage ◽  
Climatic Chamber ◽  
Desorption Process ◽  
Adsorption Sites ◽  
Differential Enthalpy ◽  
Kinetics Of

ABSTRACT This study aims to determine the thermodynamic properties of damaged beans. Grains with initial moisture content of 53.85% (d.b.) were used. A part of the grains was used to obtain the desorption isotherms, while another part was subjected to drying until a moisture content of 5.26% (d.b.) was achieved; therefore, it was subjected to the adsorption process. To induce damage, a Stein breakage tester was used. To obtain the equilibrium moisture content, grains were placed in a climatic chamber whose temperatures were 20, 30, 40, and 50 ± 1 °C combined with a relative humidity of 30, 40, 50, 70, and 90 ± 3%. Although in the desorption process, damaged grains had a lower differential enthalpy compared with the control, the reverse behavior was observed in the adsorption process. Mechanical damage caused the formation of a greater number of available adsorption sites, resulting in higher differential entropy values in adsorption and lower values in desorption compared with the control. The mechanical damage had no effect on the Gibbs free energy.

The chemisorption of hydrogen on nickel

1960 ◽  
Vol 257 (1290) ◽  
pp. 291-301 ◽  
Keyword(s):  
Progressive Increase ◽  
Heat Of Adsorption ◽  
Adsorbed Hydrogen ◽  
Adsorption Potential ◽  
Complete Coverage ◽  
Fractional Coverage ◽  
Heats Of Adsorption ◽  
Molar Entropy ◽  
Ionization Gauge ◽  
Instantaneous Position

The pressure of hydrogen in equilibrium with hydrogen adsorbed on nickel films produced by evaporation was measured by means of an ionization gauge. Observations were made at tem­peratures up to 200 °C and included a previously unexplored range of surface coverages, θ , down to about θ ═ 0⋅005. From the results the molar and differential entropies of the adsorbed hydrogen at 25 °C and the integral and isosteric heats of adsorption were calculated. The molar entropy in the range θ ═ 0 to 0⋅4, agreed satisfactorily with the view that the adsorbed hydrogen was localized on sites which were energetically homogeneous. However, the entropy and the heat of adsorption indicated that there were sites of higher adsorption potential which amounted to about 1⋅5 % of the surface. As θ increased from 0⋅4 to 1⋅0 the observed molar entropy at 25 °C indicated a progressive increase in the proportion of the adsorbed hydrogen which, at any moment, was migrating over the surface. This proportion, and the activation energy for migration, were calculated by comparison with the entropies of ideal systems. Near complete coverage the adsorbed hydrogen exhibited the behaviour of a two-dimensional gas. Indeed, over the range θ ═ 0⋅5 to 1⋅0 the strength of the hydrogen-metal bond was but little influenced by the instantaneous position of the hydrogen atom relative to the surface nickel atoms. In the range θ ═ 0 to 0⋅77 it was found that at a fixed fractional coverage the heat of adsorption was independent of temperature.

scholarly journals Molecular Simulation of Hydrogen Storage in Ion-Exchanged X Zeolites

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Xiaoming Du
Keyword(s):  
Adsorption Capacity ◽  
Hydrogen Adsorption ◽  
Isosteric Heat ◽  
Heat Of Adsorption ◽  
Adsorption Sites ◽  
Hydrogen Molecules ◽  
Adsorption Temperature ◽  
X Zeolites ◽  
Cation Type ◽  
Simulated Distribution

Grand Canonical Monte Carlo (GCMC) method was employed to simulate the adsorption properties of molecular hydrogen on ion-exchanged X zeolites at 100–293 K and pressures up to 10 MPa in this paper. The effect of cation type, temperature, and pressure on hydrogen adsorption capacity, heat of adsorption, adsorption sites, and adsorption potential energy of ion-exchanged X zeolites was analyzed. The results indicate that the hydrogen adsorption capacity increases with the decrease in temperatures and the increase in pressures and decreases in the order ofKX<LiX<CaX. The isosteric heat of adsorption for all the three zeolites decreases appreciably with the increase in hydrogen adsorption capacity. The hydrogen adsorption sites in the three zeolites were determined by the simulated distribution of hydrogen adsorption energy and the factors that influence their variations were discussed. Adsorption temperature has an important effect on the distribution of hydrogen molecules in zeolite pores.

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