Water/Ethanol Selectivity of New Organic‐Inorganic Hybrid Membranes Fabricated from Poly(vinyl alcohol) and an Oligosilane

Abstract

To control the swelling of PVA membranes, mixtures of PVA and an inorganic oligosilane were prepared using sol‐gel reactions to yield new PVA/oligosilane hybrid membranes. In the separation of an ethanol/water azeotropic mixture during pervaporation, the effect of the oligosilane content on the water/ethanol selectivity of PVA/oligosilane hybrid membranes was investigated. The water/ethanol selectivity of PVA/oligosilane hybrid membranes was higher than that of PVA membranes, but the water/ethanol selectivity of hybrid membranes decreased with increasing oligosilane content. In order to increase the water/ethanol selectivity, PVA/oligosilane hybrid membranes were annealed. The water/ethanol selectivity of annealed PVA/oligosilane hybrid membranes was greater than un‐annealed hybrid membranes, and significantly governed by the oligosilane content, which could be attributed to both sorption and diffusion selectivities. The relationship between the structure of un‐annealed and annealed PVA/oligosilane hybrid membranes along with permeation and separation characteristics of an ethanol/water azeotropic mixture during pervaporation are discussed in detail.magnified image

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