Pervaporation membranes: Preparation, characterization, and application

Pervaporation (PV) is applied in liquid mixtures separation by using non-porous membranes. The feed liquid is directly in contact with one side of the membrane and the permeation of target compounds through the membrane, in a vapour phase, is achieved by the difference in chemical potential gradient established by a difference in the partial pressure. The present chapter will focus on the membrane material and their application in PV. Organic and inorganic membranes can be both used in PV, and the choice of the most suitable membrane material is of fundamental interest for the success of the separation. Therefore, a paragraph is devoted to the investigation of the proper material, on the basis of its chemical-physical properties, that has to be selected for making membranes with the best performances in terms of selectivity and permeability. Then, the most common techniques applied for PV membrane characterization as well as the different module configurations, employed both at lab and industrial scale, are also discussed. Finally, the different types of membranes, on the basis of their application, hydrophilic PV, organophilic PV and organic/organic PV, are evaluated and the performances reported. The future trends and innovation of PV membranes is also foreseen and contextualised in the continuing growing membrane scenario.