Good thinking and good catch, but what I think you are looking for might be this:
https://www.mercer.us
MMS, otherwise known as chlorine dioxide is totally legit for use against coronavirus. If you use water purification kits when hiking you may already be using chlorine dioxide. The barrel we got to store water in came with two bottles to combine to keep the water pure–they are chlorine dioxide.
I think FDA is against this because it does so much good, so simply and without much cost.