Scaling and fouling in membrane distillation for desalination applications: A review

Membrane distillation (MD) has become an area of rapidly increasing research and development since the 1990s, providing a potentially cost effective thermally-driven desalination technology when paired with waste heat, solar thermal or geothermal heat sources. One principal challenge for MD is scaling and fouling contamination of the membrane, which has gained growing attention in the literature recently as well. The present paper surveys the published literature on MD membrane fouling. The goal of this work is to synthesize the key fouling conditions, fouling types, harmful effects, and mitigation techniques to provide a basis for future technology development. The investigation includes physical, thermal and flow conditions that affect fouling, types of fouling, mechanisms of fouling, fouling differences by sources of water, system design, effects of operating parameters, prevention, cleaning, membrane damage, and future trends. Finally, numerical modeling of the heat and mass transfer processes has been used to calculate the saturation index at the MD membrane interface and is used to better understand and explain some of trends reported in literature. © 2014 Elsevier B.V. All rights reserved.

Scaling and fouling in MD are found to be pervasive, but design and mitigation methods have proven effective at making MD technology resistant to scaling and fouling. Four principal types of fouling and membrane damage have been found in MD: inorganic salt scaling or precipitation fouling, biofouling, particulate fouling, and chemical Table 2 Common cleaning methods used in MD and reported flux recovery. S No Ref Membrane material Solution type [121] PTFE