Robust and high selective chitosan asymmetric Membranes: Relation between microporous structure and pervaporative efficiency in ethanol dehydration

•Asymmetric membranes are prepared in the presence of ethanol in chitosan solution.•Fabricated membrane is used for ethanol dehydration via pervaporation.•Changes of membrane structure during pervaporation process are extensively analyzed.•Analysis of transport parameters for transient and quasi-stationary state is provided.