Prediction of methane diffusion coefficient in water using molecular dynamics simulation

Hojatollah Moradi; Hedayat Azizpour; Hossein Bahmanyar; Mohammad Mohammadi; Mahdi Akbari

doi:10.1016/j.heliyon.2020.e05385

Prediction of methane diffusion coefficient in water using molecular dynamics simulation

Heliyon. 2020 Nov 2;6(11):e05385. doi: 10.1016/j.heliyon.2020.e05385. eCollection 2020 Nov.

Authors

Hojatollah Moradi¹, Hedayat Azizpour^{1

2}, Hossein Bahmanyar¹, Mohammad Mohammadi¹, Mahdi Akbari¹

Affiliations

¹ Surface Phenomenon and Liquid-Liquid Extraction Research Lab, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran.
² Department of Chemical Engineering, Fouman Faculty of Engineering, College of Engineering, University of Tehran, Iran.

Abstract

Diffusion coefficient is one the most effective factors in mass transfer calculation, which plays an important role in study at the molecular scale. In this study, Material Studio software was used to simulate the diffusion coefficient of methane in water through molecular dynamics. COMPASS force field was also used for optimization of atomic structures of methane and water, and Group-Based method was applied to model to calculate both van der Waals and electrostatic forces. In addition, Universal force field was used to optimize of amorphous cell, while Ewald and Atom-Based methods were applied for modeling and calculation of van der Waals and electrostatic potential energy at constant temperatures. The simulation duration for equilibrium of amorphous cell in both state of NVT and NVE was assumed 5ps. The impact of temperature as well as concentration on diffusion coefficient were investigated and results showed that the diffusion coefficient had linear relationship with temperature and third-degree polynomial relationship with concentration. As a result, of the simulation, the diffusion coefficient function versus temperature and concentration was developed.

Keywords: Chemical engineering; Diffusion coefficient; Mechanical engineering; Methane; Molecular dynamics simulation; Organic chemistry; Petroleum engineering; Theoretical chemistry.