“Our first generation of ceramic nanofiltration membranes had a molecular weight cut-off of 450 Da,” Ingolf Voigt, one of the engineers behind the project, told Digital Trends. The first filtration plant was commissioned in 2002. Since then the team has focused on making its filtration even more sensitive.
“We learned from many field tests that a lower cut-off would be beneficial for certain applications,” Voigt said. “So we started the development of the second generation of ceramic nanofiltration membranes with a cut-off of 200 Da.”
Fraunhofer’s filters are long tubes with layers of membranes, the innermost of which is the specialized filter. As dirty water is pumped through the tube, particles get caught in the membrane and clean water is pushed out to the exterior. The result looks like a pipe sweating clean condensation.
These ceramic nanofiltration membranes have a number of uses, Voigt said. For one, they can be used to treat “produced water,” completely removing organic compounds and removing some salts up to 80 percent. Since the filters are durable, they can also be used to process water with extreme heat and caustic chemicals.
The tubes, which were commissioned by Shell, have undergone trials at a plant in Canada, where they have been extracting oils and sand from water since 2016.
Beyond the factory, the researchers hope their filtration tech will be used to provide communities around the world with potable water.