Membrane Fouling in Desalination

Clean and safe water scarcity due to population growth and industries development is a very important challenge, worldwide. As the demand for clean water increases, policies such as seawater desalination and wastewater reuse have been implemented in some countries. Membrane-based desalination is recognized as one of the promising ways to address the global challenge of water scarcity. Today, membrane-based desalination using polymeric membranes with many advantages has been considered as one of the most important methods to produce clean water, worldwide. Fouling as the most important challenge facing polymeric membranes limits the performance of membrane in long-term operation. Occurrence of fouling leads to decreasing membrane life, permeation flux and rejection, and also increasing transmembrane pressure and operating costs. There are several ways to control fouling in the membrane desalination processes including membrane surface modification, novel membrane development, pretreatment, membrane monitoring, and membrane cleaning. The advancement of nanotechnology has revolutionized the membrane desalination industry. Novel nanomaterials, especially graphene oxide (GO) and carbon nanotubes (CNTs), have been identified as promising candidates for the modification of high-performance desalination membranes. Using these nanomaterials, higher water flux than that of the conventional RO membranes could be obtained, successfully. Therefore, fabrication of novel membranes using new materials and via novel methods can be effective in delaying fouling phenomena and therefore increasing efficiency of the membrane desalination processes. Also, membrane surface modification by coating and grafting methods can delay the membrane fouling by altering the properties of membrane surface including hydrophilicity and roughness. In this chapter, after recognizing fundamentals of membrane fouling and fouling types, recent advances in preparation and evaluation of new desalination membranes with improved antifouling properties are being reviewed.