Not physically encapsulating... but that's probably an OK way to think of it. Not sure of the actual chemistry, but all the ammonia "removers" just convert the ammonia (NH3
) to something that is not toxic to fish - it binds the ammonia chemically to other molecules.
Prime is good stuff, but the problem (in my opinion, at least) with using it is that the ammonia that's been bound up and deemed safe will still show up with your ammonia test kit. So even using Prime, the ammonia won't go to zero as shown in your testing - but it is supposedly safe because it's in a different form. So basically... you have to keep using the Prime because you don't know if the ammonia you're measuring is the safe stuff, or new untreated ammonia. Hope that makes sense.