Gas Separation Membrane: An Overview

摘要

Gas separation through a membrane is a pressure-driven process where the driving force can be called as the pressure difference between the raw material inlet and the product outlet. The membrane technique is generally used in non-porous sheet such that there is no gas leakage through the membrane. Membrane performance depends on the permeability and selectivity. Permeability is affected by the size of the penetrant and large gas molecules have a low diffusion co-efficient. The flexibility of the polymer chain and the free volume in the polymer of the membrane material affect the diffusion co-efficient, as the space inside the permeable membrane must be large enough for gas molecules to diffuse. The solubility is expressed as the ratio between the concentration of the gas in the polymer and the pressure of the gas in contact with it.