Pervaporation Purification of Ethylene Glycol Using the Highly Permeable PIM-1 Membrane

Ethylene glycol (EG) is an essential chemical and forms mixtures with water or methanol in the production processes. Its purification is imperative in the production of pure EG from its water/methanol mixtures. Conventionally, distillation is employed in this separation process at the expense of massive energy consumption. Here water/methanol–EG mixtures are separated by the highly permeable PIM-1 membrane via pervaporation to produce the pure EG product. PIM-1 is one of most representative polymers of intrinsic microporosity (PIMs) that are attractive membrane materials. The overall separation performances for water/methanol–EG mixtures are investigated systematically. The membrane shows good separation performances as well as high purifying efficiency. Typically, the membrane has a high flux of 10.40 kg μm m–2 h–1 and separation factor of 24.2 in the pervaporation of methanol (18.50 wt %)–EG mixtures at 30 °C. In addition, effects of feed composition and temperature are investigated respectively on the separation performances. The flux and separation factor increases simultaneously with the water/methanol content in feed, whereas the separation factor decreases with increasing feed temperature for the methanol–EG mixture and the opposite for the water–EG mixture. The PIM-1 membrane shows a great potential in the EG purification industries.