Paper title: Molecular Dynamics Simulations of Osmosis and Reverse Osmosis in Solutions
Journal: Adsorption 2, 95-101 (1996)

Author: S. Murad
Chemical Engineering Department, University of Illinois in Chicago, Chicago IL 60607, USA

Summary: 
Using molecular dynamics, the paper investigated what happens during osmosis, reverse osmosis and the transition between them. 

By manipulating the solution concentration, and, density difference between solvent and solution compartments, Murad was able to achieve a smooth transition from an impermeable membrane to a semi-permeable one, then finally, to a totally permeable membrane.

Using two setups that have different distances between two membranes, Murad was also able to study the wall effects for the system. As a consequence, the simulation gave more opportunities to elucidate adsorption effects of particles on the membrane.

Aside from adsorption, the simulations done were able to calculate other quantities for the system. The diffusion coefficients of both solute and solvent particles were measured by utilizing the mean squared displacements. In addition, density profiles for both solute and solvent were obtained. Osmotic pressure was also found to vary linearly with the number of solute molecules in the solution compartment.


Contribution and application:

This paper gives an example of applying MD simulations in gaining deeper understanding of membrane processes. By modifying the general MD procedure, computer simulations may also be applied in studying the membranes and processes of forward osmosis, membrane distillation, MBR, etc.

 

By: Hannah Ebro

hannah@gist.ac.kr