What you are thinking of is an air scrubber, which filters the air for you. But it's a good idea to call in a professional, who will have the equipment and can also figure out if something still has to be done at the source of the damage.

There's an additive for paint that you can buy at home depot and add to whatever paint you put on the wall to make it more mildew resistant. I have only used it in my bathrooms though.

kilz primer

run fan to circulate air and get another dehumidifier or borrow one.

damp rid

I got some water damage in my basement. We are in the process of ripping out all the damaged material and are running a dehumidifier. Is there an additional product that helps refresh the air and get rid of lingering moisture odor? Thanks.