BACKGROUNDIn this study, a polyethersulfone composite hollow fiber membrane was used for the separation of water vapor from mixed gas. For improvement of the separation properties, the fabricated membrane was coated with cellulose acetate (CA) and polyethylene glycol (PEG). RESULTSExperiments on the permeation of water vapor and N-2 gas mixture were performed to observe membrane behavior as a function of the coating conditions, such as the composition and molecular weight of PEG. The water vapor permeance and selectivity of water vapor/N-2 improved from 68.5 GPU to 444.1 GPU and from 76.1 to 175.5, respectively, using 5 wt% PEG 2000 blended coating solution. CONCLUSIONAn increase in the PEG content and molecular weight of the coating solution affected the permeance and selectivity due to the hydrophilicity of PEG and the structural changes of the coating layer. (c) 2014 Society of Chemical Industry