Pervaporation dehydration of aqueous ethanol and isopropanol mixtures through alginate/chitosan two ply composite membranes supported by poly(vinylidene fluoride) porous membrane

Composite membranes consisting of an active alginate layer and supporting c hitosan layer on top of the base porous blended polyvinylidene fluoride (PV DF) membrane were prepared and tested for pervaporation dehydration applica tions. Efforts to enhance the surface properties of PVDF by blending with r elatively hydrophilic polymethyl methacrylate (PMMA) were carried out and e valuated by contact angle measurements. Various modifications for the algin ate/chitosan composite membranes such as converting to the free acid form a nd cross-linking with cobalt ion;were investigated. They were then compared for the pervaporation dehydration of ethanol/water and isopropanol/water m ixtures and the temperature effect on the permeation flux was also investig ated. (C) 2000 Elsevier Science B.V. All rights reserved.