Fluorine nanostructures can desalinate water 2,400 times faster than carbon nanotubes

Some of Earth’s 3 million cubic miles (13 million cubic km) of salt water.

Imagine a cross-section of a strand of hair. That tiny surface — roughly one-millionth of a meter in diameter — is huge compared to the pores in a new type of filter developed by engineers at the University of Tokyo in Japan.

In a paper published Thursday in the peer-reviewed journal Science , the researchers unveiled their new method for desalinating water using rings of fluorine just one to two nanometers in diameter. The chemical’s hydrophobic properties contributed to its remarkable ability to filter salt molecules with impressive speed and efficiency.

Laid out end-to-end, it would take nearly 100,000 of the rings to stretch all the way across the cut surface of a human hair.

“It was very exciting to see the results firsthand,” says materials engineer Yoshimitsu Itoh , one of the paper’s co-authors. “The smaller of our test channels perfectly rejected incoming salt molecules, and the larger channels too were still an improvement over other desalination techniques and even cutting-edge carbon nanotube filters.”