Hello. New guy here.
I just did a 'net review of reactivating carbon air filters. How its done depends very much on what it has adsorbed. It depends also on what parameters the container will withstand - specifically, in my case, temperature.
When I have to do it, when the price of replacement is too high, then I will try things like; the strongest oxidant that I can find (H2O2 35%) and baking it in the oven at the highest temperature that the plastic 'container' will remain dimensionally stable.
I registered here precisely to inquire after ideas on reactivation of a household activated carbon air filter that is the post-filter on my electrostatic filter. I am very pleased with it.