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How does pervaporation membrane work?

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The separation mechanism of pervaporation membranes is mainly a dissolution diffusion process, which is a membrane technology that uses dense polymer membranes to separate the components of liquid mixtures and dissolve diffusion properties.
In fact, the mass transfer process of pervaporation membranes can be divided into three parts: (1) small molecules are dissolved by permeation on the surface of the side membrane; (2) Diffusion through a membrane under gradient action; (3) Evaporation on the surface of the permeation side membrane.
In a typical operating environment, the third step (vaporization process) is very fast and has almost no impact on the entire mass transfer process, while the first step (dissolution process) and second step (diffusion process) not only depend on the polymer film. The properties and states are also closely related to the properties of permeable molecules, as well as the interactions between permeable molecules and polymer materials. Therefore, the pervaporation membrane evaporation process is actually a study of the dissolution diffusion process.
After heating the organic mixture to a certain temperature, it is placed in contact with the membrane on one side of the pervaporation membrane at atmospheric pressure, and the other side (downstream side) of the membrane is evacuated or the carrier gas is blown to maintain low pressure. Therefore, the osmotic components dissolve and diffuse through the membrane under the vapor partial pressure difference (or chemical gradient) on both sides of the membrane, evaporate on the surface of the permeate side of the membrane, and the vapor is directly discharged or cooled. The condenser is then converted into a liquid state, and the residue that does not pass through the membrane flows directly out of the membrane separator, thereby achieving the purpose of concentration and separation.