(159g) Simulation of the Gas Separation in Hybrid Inorganic-Organic Membrane

Membrane separation is widely used
in the energy industry for gas mixtures. For decades, experimentalists have
invested a significant amount of time to develop novel membranes with better
efficiency and selectivity. Understanding the mechanistic steps in the
separation can lead to better membrane designs and shorter development.

The gas separation process is
simulated with the hybrid inorganic-organic membrane model constructed from our
previous study, which used MD with BKS force field to generate amorphous silicon
dioxide and followed by MD with Dreiding force field
to optimize the hybrid membrane structure. To obtain the permeability and
selectivity of the membrane, non-equilibrium molecular dynamics must be applied
to vary the number of molecules. Thus the dual control volume grand canonical
MD (DCV-GCMD) method is used with Dreiding force field.
At 400K with the feed pressure of 4MPa, the permeability of CO²
 is  3.05×10^-7 mol m^-2 s^-1
Pa^-1 and that of CH⁴ is  5.00×10^-8 mol m^-2 s^-1
Pa^-1. The calculated properties are compared with the experimental
data of the specific membrane.

We are currently investigating the
relation between the ability for separation of the membrane and the characters
of the structure of the membrane, the size of the pore, the number of phenyl
group in the structure, etc. Also we are studying to improve the simulation
result by using different force field.