Computational Molecular Modeling of Transport Processes in Nanoporous Membranes

Abstract

Abstract:In this report we have discussed the important role of molecular modeling, especially the use of the molecular dynamics method, in investigating transport processes in nanoporous materials such as membranes. With the availability of high performance computers, molecular modeling can now be used to study rather complex systems at a fraction of the cost or time requirements of experimental studies. Molecular modeling techniques have the advantage of being able to access spatial and temporal resolution which are difficult to reach in experimental studies. For example, sub-Angstrom level spatial resolution is very accessible as is sub-femtosecond temporal resolution. Due to these advantages, simulation can play two important roles: Firstly because of the increased spatial and temporal resolution, it can help understand phenomena not well understood. As an example, we discuss the study of reverse osmosis processes. Before simulations were used it was thought the separation of water from salt was purely a coulombic phenomenon. However, by applying molecular simulation techniques, it was clearly demonstrated that the solvation of ions made the separation in effect a steric separation and it was the flux which was strongly affected by the coulombic interactions between water and the membrane surface. Additionally, because of their relatively low cost and quick turnaround (by using multiple processor systems now increasingly available) simulations can be a useful screening tool to identify membranes for a potential application. To this end, we have described our studies in determining the most suitable zeolite membrane for redox flow battery applications. As computing facilities become more widely available and new computational methods are developed, we believe molecular modeling will become a key tool in the study of transport processes in nanoporous materials.

Xenon Recovery by DD3R Zeolite Membranes: Application in Anaesthetics

“…[44] Thesystem set-up is shown in Figure 4a,w hich results in ad riving force perpendicular to the membrane surface. [45] All simulations are carried out under non-equilibrium conditions using the LAMMPS simulation package. [46] Thes ystem volume was kept constant and Nose-Hoover style non-Hamiltonian NVT ensemble was used to maintaint he temperature at 300 K. [47] Time integration allowed us to monitor the time evolutiono ft he position and velocities of all moleculesi nt he system.…”

Interfacial Thermal Conductivity and Its Anisotropy

“…We investigated three working fluids confined within copper walls [5]. This special design also facilitated the equilibration by increasing interfacial surface area, which had been documented in our previous studies [28][29][30][31], and proved effective in investigating solid-fluid interfacial thermal conductivities [2][3][4]. Figure 1 shows a schematic Processes 2020, 8,27 3 of 18 sketch of a system set-up with a size of 130.14 × 65.07 × 28.92 Å in the x, y, z dimensions, respectively, that contains a liquid between solid walls.…”

Textile Wastewater Treatment for Water Reuse: A Case Study

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