Membrane Distillation. Materials and Processes

Desalination is imperative to mitigate the global water scarcity as it produces drinking water from unpotable water. Currently, reverse osmosis membrane processes are widely used and account for 60% of desalination plants globally as they have lower energy requirements than other techniques, such as thermal desalination. Another promising alternative to desalination is membrane distillation (MD), which has been highlighted as one of the most promising and cost-effective desalination technologies over the last five decades. MD is a thermally driven desalination process that uses microporous and hydrophobic membranes through which only vapor can pass. Because non-volatile ions cannot pass through the membrane, MD theoretically achieves 100% salt rejection. In addition, MD is superior to other techniques as it is conducted at relatively low temperature and pressure, and is less sensitive to the feed concentration. MD is a desalination process that uses the vapor pressure difference between the feed and permeate as the driving force through the membranes