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Permeation evaporation film for dehydration purification

Permeation evaporation film for dehydration purification is generally made of hydrophilic film material, and the composite film type separation film made of hydrophilic thin activation layer on a microporous support is most popular. In order to make this layer, first of all microporous support using polysulfone or polyetherimide is manufactures, which is then coated with hydrophilic polymer material. The coated layer is crosslinked by various methods in order to make it water insoluble. The hydrophilic polymers for this purpose are poly(vinyl alcohol) and various ionic polymers. The compounds with aldehyde ligands are used for their crosslinking. The hydrophilic polymer in this study can absorb water selectively in a mixed solvents, and the absorbed water can easily pass through a microporous supports. The performance of separation layer is affected by material, thickness of activation layer, crosslinking, and the shape of separation layer.The characteristics of the separation layer is it can separate azeotropic mixtures with small energy, which is difficult to separate by a distillation method. This is a very strong point of this separation layer. Also, the separation process using this separation layer is very simple, so that facility investment is minimized, and is highly economical. This separation layer has very high separation factor and high permeability, so the separation efficiency is high.