Factors Affecting Membrane Distillation Process for Seawater Desalination

Membrane distillation (MD), a process based on the thermal principle, is a combination of distillation and membrane separation in the same unit. There are many factors that can affect the MD performance, but the membrane characteristics are the most important in this process. The changes in the membrane properties affect the process efficiency, the permeate flux as well as the membrane lifetime. Some of the membrane properties mentioned in this paper include liquid entry pressure (LEP), contact angle, pore size, porosity, thickness, thermal conductivity, support layer, tortuosity, etc. This review paper aims to evaluate the membrane properties in order to reduce membrane wetting and to improve desalination efficiency. From this review, it can be seen that the LEP and contact angle are the important factors which directly affect the hydrophobicity of the membrane. When LEP and the contact angle increase, the hydrophobicity of the membrane increases. Thus, the membrane is durable and the MD system works efficiently. The remaining factors indirectly affect the operation of the MD system through LEP and contact angle (hydrophobicity).