Scientists have transformed a piece of wood into a membrane that can filter saltwater.
Traditional membrane distillation involves pumping saltwater though a film that's usually made of plastic. The plastic membrane features extremely narrow pores that block salt from passing, only allowing access to water molecules.
Princeton researchers have developed a similar technique but using wood.
“If you think of traditional water filtration, you need very high-pressure pumping to squeeze the water through, so it uses a lot of energy,” said lead researcher Jason Ren. “This is more energy efficient and it doesn’t use fossil-fuel based materials like many other membranes for water filtration.”
Ren and his team chemically-modified a thin slice of American basswood, removing the wood's extra fibers to make its surface slippery to water. That side is also heated, which vaporizes the saltwater - allowing the vapor to pass through the wood's pores. As the vapor reaches the cool side, it condenses into cool freshwater.
Ren says the filtering process isn't as quick as it is with plastic, but its advantage is sustainability.
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