Granted, even th eidea that radio waves can target cancer cells is off the normal beaten track, but that's what this retired radio guy has been working on. The sodium is not necessarily bonded to teh hydrogen or oxygen, just dissolved, that's why you can evaporated or distill saltwater ans end up wit hsalt. I am leaning toward this being a sodium burn, which may or may not be usable as a newenergy source, however it could reduce the energy input in desalination of salt water.
But it's not sodium metal
that's dissolved in the water. It's sodium ions
! There's a huge difference. In becoming a cation, a sodium ion gains an electron (Na+). In chemistry, we call gaining an electron "oxidation." So you can't further oxidize a sodium ion. To get back to sodium metal would require abstracting an electron away from the sodium ion, which would require a huge energy cost--much more than you'd be able to recoup by burning the sodium.
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam.