Pervaporation separation of water and dioxane mixtures with sodium alginate-g-polyacrylamide copolymeric membranes

Polyacrylamide (pAAm)-grafted sodium alginate (NaAlg) copolymeric membranes have been prepared and used in the pervaporation separation of dioxane mixtures containing10-70 mass % water. Three different polymeric membranes have been prepared: neat NaAlg, 46% grafted pAAm-g-NaAlg, and 93% grafted pAAm-g-NaAlg. For reduced brittleness and increased flexibility of the membranes, 10 mass % poly(ethylene glycol) and 5 mass % poly(vinyl alcohol) were added to all three membranes. With the transport data for the mixtures through the membranes, the permeation flux, selectivity, pervaporation separation index, swelling index, and diffusion coefficients have been calculated at 30degreesC. The Arrhenius activation parameters for the transport processes have been calculated for 10 mass % water in the feed mixture with flux and diffusion data obtained at 30, 40, and 50degreesC. (C) 2003 Wiley Periodicals, Inc.