Specially Treated Biochar Could Destroy PFAS "Forever Chemicals" (WOW!)

Holy smokes, this is amazing! Researchers found a way to pre-treat wood chips with iron chloride to produce biochar that captures and in initial tests destroys some PFAS, the infamous "forever chemicals."

https://www.cbc.ca/news/canada/british-columbia/goodbye-forever-chemicals-1.7330391

Excerpt:

"There's no natural way for this thing to break down," said Johan Foster, an associate professor of chemical and biological engineering in the University of British Columbia's Faculty of Applied Science and the senior researcher on the team that developed the technology.

"They have found [forever chemicals] in everything from glaciers to mountain lakes to killer whales."

But by soaking wood chips in an iron chloride solution, then burning them at a high temperature, Foster's team was able to produce a new type of activated carbon that can capture and destroy forever chemicals.

The results by UBC researchers were recently reported in a peer-reviewed paper in Nature Communications Engineering.

Essentially, the iron-soaked, burnt wood chips – or "biochar" – act as a more effective form of activated carbon, grabbing PFAS molecules out of the water. The iron then acts as a catalyst, making it easier to snap those strong carbon-fluorine bonds.

"The PFAS compound attaches to the catalyst and then a reaction basically degrades it into smaller and smaller innocuous compounds that won't affect the human body," said Foster.

When ground into a powder, the material was able to destroy over 85 per cent of perfluorooctanoic acid (PFOA), a common type of PFAS, within three hours. These results were collected under low levels of ultraviolet light to simulate ambient sunlight, but the reaction is only slightly less efficient in the dark.

This is great stuff. Several of the researchers that I'm in touch with have been excited about iron as a pre- and post-pyrolysis additive for lots of applications where something needs to be picked up or pulled out. Apparently the multiple valence states make it a valuable component of the organo-mineral complexes that form on the molecular level when biochar ages in soil or water, and by "spiking the punch" with Fe atoms you get much more attractive sites for contaminants to dock.

Destroying PFAS is next level awesomeness, though. Now I have another thing to tell the environmental remediation folks at a conference next month.

Great thread, Douglas! I love it when scientists do something epic like this instead of finding ways to create more pollution.  This will be a big game changer.  A lot of people are worried about these "forever Chemicals".

John S
PDX OR