scholarly journals Adsorption And Diffusion of The H2/CO2 /CO /MeOH /EtOH Mixture Into The ZIF-7 Using Molecular simulation

Author(s):  
Zahra Keyvanloo ◽  
Ali Nakhaei Pour ◽  
Fatemeh Moosavi

Abstract The adsorption and diffusion of synthesis gas components (methanol, ethanol, H2, CO2, and CO molecules) in ZIF-7 by grand canonical Monte Carlo and molecular dynamics simulation were investigated. The initial diffusion coefficient at the beginning of the process depends on the kinetic diameter of the guest molecules. Also, the diffusion coefficient at equilibrium conditions probably depends on the interaction between the guest molecules with the ZIF-7 framework. The radial distribution function results indicate that the distribution of guest molecules in the framework is affected by the interaction between the guest molecules. These results also demonstrate that the Zn atom and the organic linker are favorable sites for CO2, CO, and H2. In contrast, the organic linker is the most favorable adsorption site for methanol and ethanol guest molecules. In addition, the diffusion coefficient of guest molecules in binary mixtures is related to the attraction or repulsion between the guest molecules.

2015 ◽  
Vol 1095 ◽  
pp. 363-366
Author(s):  
Guo Cai Tian ◽  
Ding Wang

The molecular dynamics simulation method is used to study volume properties and diffusion of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])/ethanol mixture with different molar fractions of ethanol. It is found that the density of the mixture decrease with the increasing of the mole fraction of ethanol, whereas the diffusion coefficient increases. The excess molar volume all appear negative over the entire mole fraction of ethanol which agree well with experimental results.


2006 ◽  
Vol 51 ◽  
pp. 140-144 ◽  
Author(s):  
E. Semprini ◽  
G. Perez ◽  
Ferdinanda Stefani ◽  
Patrizia Cafarelli ◽  
A. De Stefanis ◽  
...  

Experimental results indicate that conformational changes of organic molecules occurring in the gaseous and in the liquid phase are hindered or lowered in constrained environments like zeolite pores. A successful understanding of the processes occurring in this type of materials requires a good description of the equilibrium properties, which can be calculated by the Grand Canonical Monte Carlo method. In particular, in the present work conformational changes, such as boat → chair for cyclohexane, are studied by molecular dynamics simulation, as a function of pore size and temperature.


2020 ◽  
Vol 11 (1) ◽  
pp. 282
Author(s):  
Yogeshwaran Krishnan ◽  
Mohammad Reza Ghaani ◽  
Arnaud Desmedt ◽  
Niall J. English

The inter-cage hopping in a type II clathrate hydrate with different numbers of H2 and D2 molecules, from 1 to 4 molecules per large cage, was studied using a classical molecular dynamics simulation at temperatures of 80 to 240 K. We present the results for the diffusion of these guest molecules (H2 or D2) at all of the different occupations and temperatures, and we also calculated the activation energy as the energy barrier for the diffusion using the Arrhenius equation. The average occupancy number over the simulation time showed that the structures with double and triple large-cage H2 occupancy appeared to be the most stable, while the small cages remained with only one guest molecule. A Markov model was also calculated based on the number of transitions between the different cage types.


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