PERVAPORATION SEPARATION OF ETHYLENE GLYCOL-WATER MIXTURES USING CROSS-LINKED PVA-PES COMPOSITE MEMBRANES .1. EFFECTS OF MEMBRANE PREPARATION CONDITIONS ON PERVAPORATION PERFORMANCES

A composite membrane with a crosslinked PVA dense active layer dip coa ted on a polyethersulfone support membrane was prepared and evaluated with a pervaporation setup for the separation of a water-ethylene glyc ol mixture. The effects of preparation conditions including heat-curin g temperature and time, dehydration rate, cooling rate, structure of s upport and crosslinking density of the crosslinked PVA active layer on the separation factor and permeate flux are discussed. Optimum result s were obtained with crosslinked PVA membranes containing 3.7 wt% cros slinking agent and 0.05 wt% catalyst, giving a separation factor of 23 1 and a permeation rate of 383 g/(m(2) h) for a 82.5 wt% ethylene glyc ol aqueous solution at 80 degrees C.