Membrane distillation (MD) is a thermally driven separation process in which separation is driven by phase change. A hydrophobic membrane presents a barrier for the liquid phase, allowing the vapour phase (e.g. water vapour) to pass through the membrane's pores.
Membrane Distillation (MD) is a relatively new and promising separation technology that is an alternative to more energy intensive methods such as reverse osmosis or distillation. MD is a thermally driven process where only vapor molecules transfer through a hydrophobic (water repellent), microporous membrane.
A typical membrane distillation technique features a membrane filter sandwiched between cold solution on one side and hot solution on the other side. The driving force of the MD process is the partial vapor pressure difference induced by the temperature difference across the hydrophobic membrane. The vapor then condenses on the cold side to produce the distillate
MD membranes are suited for applications where water is the major component, including desalination, purification, and treatment of process water or for temperature-sensitive industrial products such as the following:
Compared to conventional membrane processes, MD has the following benefits: