Cook with a teflon-coated pan so the cooked rice won’t stick to the pan. This is because the key ingredient in PTFE is fluorine—a lightweight element that is naturally hydrophobic or hydrophobic. Teflon can also be used in pipe liners to improve water flow.
Toshiyoshi Ito, associate professor at the Department of Chemistry and Biotechnology at the University of Tokyo, and his team sought to explore how pipes, or channels, made of fluorine operate on a nanoscale, to test their effectiveness in selectively filtering different compounds, especially water and salts.
The team created the test filter by chemically synthesizing nano-fluorine rings that are stacked and embedded in otherwise impermeable lipid layers, similar to the organic molecules that make up cell walls. They created several test samples of fluorine rings that were between about 1 and 2 nanometers wide, while a human hair is almost 100,000 nanometers wide. To test the membrane’s effectiveness, the research team measured the presence of chloride ions on both sides of the test membrane.
“The smaller channel in the test completely rejected the incoming salt molecules, while the larger channel was an improvement over other desalination technologies and even cutting-edge carbon nanotube filters,” Ito said. “What really surprised me was that , this process happens very fast, thousands of times faster than typical industrial equipment and about 2,400 times faster than experimental desalination equipment based on carbon nanotubes.”
Fluorine is electronegative, it repels negative ions like chlorine in salts. This has the benefit of breaking up essentially loosely bound groups of water molecules (water clusters) so they can pass through the channel more quickly. The team’s fluorine-based water desalination membranes are more efficient, faster, require less energy to operate, and are very easy to use.
In the future, the research team hopes to improve the way the material is synthesized, increasing the lifespan of the membrane and reducing operating costs.