Posted: March 14, 2007

Forcing water through nanotubes

(Nanowerk News) Nanotubes are notorious for their water phobia, but a new study published online on February 13 in Nano Letters ("Polarity-Dependent Electrochemically Controlled Transport of Water through Carbon Nanotube Membranes ") reports using electricity not only to make the nanotubes water-friendly but also to fine-tune the rate of water flow through them.
By applying a small positive potential of 1.7 volts to the membranes of nanotubes while giving the water a negative potential, Nikhil Karotkar of Rensselaer Polytechnic Institute and his team succeeded in changing nanotubes’ water affinity—they now allowed water to pass through. And raising the water’s charge sped up its flow. The ability to micromanipulate water movement through these tiny tubes opens up new avenues for applications, including nanofiltration for supplying clean drinking water.
Source: Environmental Science & Technology