Pervaporation separation of water/ethanol mixture by TGN/PSF blending membrane

The separation performance of plasticizer/polysulfone (TGN/PSF) pervaporation membrane was studied. The optimum amount of plasticizer (TGN) in PSF membranes improved the diffusion selectivity of water to ethanol, which was due to the increase in the permeate diffusion rate difference between water to ethanol molecules. On the other hand, the solubility selectivity of water to ethanol in PSF membrane showed a minor change with increasing the plasticizer content in TGN/PSF membrane. The feed ethanol concentration showed a significant influence on the degree of swelling as well as the separation performance of TGN/PSF membrane. It was found that the dominant factor of permeate transport through membranes was the diffusion rate difference, especially at high ethanol concentrations in feed. This study indicated that a good separation performance could be achieved at high ethanol concentrations in feed. This investigation also proves that the flexible polymer chain mobility, which was due to both the addition of TGN in the membrane and the swelling effect of the membrane at the high ethanol concentration in feed solution, strongly influences the separation properties of TGN/PSF membrane. (C) 2003 Elsevier Ltd. All rights reserved.