  Energy and water issues are the two main global challenges faced by human in
the past decade. The rapid growth in global energy consumption and greenhouse
gas emissions have encouraged the exploration of renewable energy sources as
substitute fuels. Osmotic energy (or salinity-gradient energy) is the energy
released when water with different salinities is mixed, such as rivers and
oceans. By employing a semipermeable membrane to control the mixing process,
the osmotic pressure gradient energy can be generated in terms of electrical
power via pressure retarded osmosis (PRO) without causing adverse environmental
impacts. This work presents a review of the fabrication of thin film
nanocomposite (TFN) membranes which are customized to offer high flux in
forward osmosis (FO) and high osmotic power in PRO. The hydraulic pressure
during PRO processes is less than RO processes so membranes that are used for
PRO are less likely to foul. The application of these nanomaterials
incorporated with TFN membranes for power generation through PRO is still a new
field to be explored. Despite some promising findings obtained from this work,
there is always room for improvement.
