Sustainable Desalination Process and Nanotechnology

Abstract

A wide variety of methods are used for water treatment and purification. The use of membranes allows efficient treatment by reverse osmosis, nanofiltration, ultrafiltration, microfiltration, membrane distillation and forward osmosis. Membrane technology has been researched extensively for water treatment and desalination. Desalination is the technology predominantly used to solve water scarcity. The sustainability of desalination processes aims at reducing energy costs and increasing water recovery. In recent years numerous large-scale seawater desalination plants have been built in water-stressed countries. Construction of new desalination plants with the latest emerging technology is expected to increase in the future. Despite major advances in desalination technologies, seawater desalination is still more energy intensive compared to conventional processes uszd for the treatment of fresh water. However, forward osmosis and membrane distillation are emerging for sustainable desalination. In this chapter we review key points of membrane processes including advantages and disadvantages of forward osmosis and membrane distillation. The advances in membrane material and modules is also discussed elaborately. Drawbacks of forward osmosis are also highlighted within each part, including draw solution development, reverse solute diffusion, concentration polarisation and membrane fouling. This chapter discuss the capability of membrane distillation in treating highly concentrated aqueous solutions derived from other desalination processes. We review the fabrication and performance of membranes, and the optimization of membrane distillation. Finally, the sustainability and application of forward osmosis and membrane distillation in seawater desalination is elaborately analysed.