

Yes; this is something that has been studied. However as other commenters have said it requires a lot of energy, and is better suited for processing smaller quantities of water with a high level of PFAS contamination than massive quantities of water with an extremely low level of PFAS. It’s also not a standalone solution, as plenty of harmful chemicals survive heating past 400/500C (heavy metals like cadmium, lead, and mercury do not break down at any temperature).
Well… The Large Hadron Collider can smash lead nuclei together at nearly the speed of light, which turns them into something that is definitely no longer lead.