Would this work?

if you are planning on putting it into the wort it will def not work....it will foam like crazy...actually threw some in some beer the other night for fun....it was cool cuz each of the foam bubbles would pop and a small gas cloud would come out...but there was barely any beer in there and it overflowed for about 15 minutes....lol so yeah def do not throw it into beer...

for another point you want to add oxygen to wort not CO2...so that would not help that way either....if you wanted to do an ice bath with dry ice it may work but I doubt it will work much better than regular ice...

if you want to see what it will do put some wort in a glass and add some dry ice and you will see why you can't do it...lol

Dry ice + hot wort = giant cloud of C02 and hot wort exploding out of the kettle. Unless you're doing it in an ice bath, like Stinkfist said.

Also, dry ice isn't too clean. You could definitely get some crap in the wort.