Use of membrane distillation for selective recovery of chemicals like ethyl alcohol: a critical review

Abstract Separation, purification and recovery of chemicals has become an essential attribute of process industries. Process intensifications (PI) like reactive separations (RS), membrane reactors (MR) and advanced membrane separation techniques can be effectively used for this purpose. Membrane distillation (MD) has been used in applications like desalination of sea water, brackish water treatment and brine treatment. MD can also be used for recovery of volatile, nonvolatile chemicals with greater effectiveness and better economics. This review critically adjudges the application of MD for recovery of chemicals especially ethyl alcohol (ethanol, EtOH). Technical aspects like membrane configurations, membrane materials, comparison with other membrane separations, economic aspects and industrial applications are some of the key features of this review. Interplay of parameters and membrane performance is discussed. Challenges like long term sustainability, membrane fouling, scale up, hybrid processes are reviewed in considerable detail. Directions for further research are indicated.