Desalination of sodium chloride solutions and seawater with hydrophobic ceramic membranes

Desalination of seawater and NaCl solutions is of great interest as potable water sources are dramatically declining on earth. Most of the techniques used to decontaminate water involve polymeric membranes and expensive desalination processes. To improve thermal, chemical and physical resistance of these membranes, research is now focused on ceramic membranes and hydrophobic ones in particular. The technique used to desalinate water is the Air Gap Membrane Distillation (AGMD), which is more compact, less energy-consuming and required lower temperature than conventional distillation processes. Therefore, ceramic membranes of different nature, zirconia, alumina and alumino-silicate, with pore diameters of 50 nm, 200 and 400 nm, and 800 nm, respectively, were chemically modified using 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane and applied to desalination of NaCl solutions and seawater using AGMD. Highest rejection rate (>95%) and flux were measured for hydrophobic zirconia membrane (50 nm).