Membrane distillation for the treatment of waters contaminated by arsenic, fluoride and uranium

Nowadays, water is a limited natural resource and in many cases there is a lack of water with the desired quality for both industrial and domestic use. Population growth and industrialization have led to a reduction of surface water sources, forcing populations around the world to depend on groundwater sources. Both types of water are not suitable for direct consumption due to high salt concentrations and in some cases also to naturally occurring hazardous contaminants, such as arsenic (As), fluoride (F-) and uranium (U). Therefore, extensive treatments are required prior to consumption. Another source of water is the one that can be obtained with appropriate treatments of both industrial and municipal wastewater. This chapter begins with traditional techniques employed to treat water contaminated by As, F- and U. Then, the basic principles of membrane distillation are described and the research works reported in literature on the application of this membrane process to treat the polluted water are reported and discussed, in terms of permeate flux and contaminants rejection.