I wonder how healthy this "magnetic fluorinated polymer sorbent" is to drink
This is either ignorant or ill-intended and neither of those is ok.
There is plenty of epidemiological data showing the very opposite:
> Merrimack residents experienced a significantly higher risk of at least 4 types of cancer over 10 years between 2005 and 2014. Merrimack is a community with documented PFAS contamination of drinking water in public and private water sources. Results indicate that further research is warranted to elucidate if southern NH residents experience increased risk for various types of cancer due to exposure to PFAS contamination.
[0] doi: 10.1177/11786302221076707.
And as that agent will be filtered out after absorbing the PFxx compounds, there should not be any after-effects of the water treatment.
There are so many online 3M/Dupont blame shifters that I completely jumped the gun.
Filtration isn't binary, so this may only be useful in a few target areas where water sources are contaminated enough that introducing a new contaminate (these NPs) into the water will pull out more PFAS than are left behind after magnetic separation.
The NPs (or more likely the PFAS that degrade off of the Fe3O4) also may have a different health affect than PFAS in the water stream (due to sulfonation etc).
So it's certainly not that simple, but a great technology for companies trying to recover their chemical products and reactants for reuse and for areas where contamination is very bad.