Pervaporation is an emerging membrane separation
process. Recent developments in pervaporation membranes
and pervaporation processes are reviewed in this
paper, and some important questions involved in membrane
pervaporation are discussed. In particular, the
following issues are emphasized: mass transport in the
membrane, membrane material selection, concentration
polarization in the boundary layer, pressure buildup in
hollow fiber membranes, asymmetric and composite
membranes, and the activation energy for permeation.
Applications of pervaporation in industrial separations
are briefly addressed. It is difficult, if not impossible,
to give a complete in-depth review of all aspects of
pervaporation, whose technology is still developing very
rapidly. This paper attempted to provide an insight into
this dynamic field and to highlight some of the key
problems yet to be solved or clarified.