Mechanical properties of water desalination and wastewater treatment membranes

Applications of membrane technology in water desalination and wastewater treatment have increased significantly in the past few decades due to its many advantages over other water treatment technologies. Water treatment membranes provide high flux and contaminant rejection ability and require good mechanical strength and durability. Thus, assessing the mechanical properties of water treatment membranes is critical not only to their design, but also for studying their failure mechanisms, including the surface damage, mechanical and chemical ageing, delamination and loss of dimensional stability of the membranes. The various experimental techniques to assess the mechanical properties of wastewater treatment and desalination membranes are reviewed. Uniaxial tensile test, bending test, dynamic mechanical analysis, nanoindentation and bursting tests are the most widely used mechanical characterization methods for water treatment membranes. Mechanical degradations induced by fouling, chemical cleaning as well as membrane delamination are then discussed. Moreover, in order to study the membranes mechanical responses under similar loading conditions, the stress-state of the membranes are analyzed and advanced mechanical testing approaches are proposed. Some perspectives are highlighted to study the structure-properties relationship for wastewater treatment and water desalination membranes.