A summary of some carbon nanotube applications now available commercially gives a flavour of just how widespread a real impact the technology is starting to make. Take water and oil purifiers, for example. the size, surface area (500m2/g) and adsorption properties of carbon nanotubes make them an ideal membrane for filtering toxic chemicals, dissolved salts and biological contaminants from water. That makes them a potential technology for producing clean water and drinking water from the sea.