Yes, it can be vented back in to the room. Scubbed air is scrubbed air is scrubbed air.... However, you do not want to keep recycling the same air around the room, that will suffocate the plants eventually. Think of a person with bad breath being locked in a closet, you have an air scrubber in there to filter out his bad breath but his carbon dioxide keeps getting pushed around the room, eventually the bastard will die.

I am sure you will figure something out to get fresh air moving in and out.