Carbon nanotubes could provide a possible solution to the problem of the burgeoning world population demanding more and more fresh drinking water, according to Jason Reese, a professor of thermodynamics and fluid mechanics a the University of Strathclyde, United Kingdom. Worldwide demand for water is expected to increase by a third before 2030. Reese and his colleagues have used computer simulations to show how carbon nanotubes could be used to desalinate water. The team’s technique is based on “reverse osmosis”, in which water moves across a permeable membrane from a region of high solute concentration to a region with low concentration, leaving salty water clean. The pressure needed to make reverse osmosis work usually results in a process that is incredibly inefficient, making desalination too expensive. Reese has shown that the use of carbon nanotubes results in water permeability 20 times that of conventional reverse osmosis membranes, greatly reducing the cost and energy required for desalination. Reese says, “The holy grail of reverse-osmosis desalination is combining high water-transport rates with efficient salt-ion rejection. While many questions still remain, the exciting potential of membranes of nanotubes to transform desalination and water-purification processes is clear, and is a very real and socially progressive use of nanotechnology.” The team’s findings were published in the journal Physics World.
http://www.eurekalert.org/pub_releases/2011-05/iop-fst052611.php