Creative idea, I wonder how long it will last until you need to refresh it with new kitty litter.

FWIW you can get good deals on bulk activated carbon for making your own all carbon filters fairly cheaply on ebay.
Doc 007 Reviewed by Doc 007 on . MOST EFFICIENT CARBON FILTER FOR UNDER 10$ this was really simple basically i went to the grocery store bought the cat carbon crystals drilled holes throughout the container and taped a fan on top so that the fan blows into it i basically have it running right next to my plants i have 4 budding plants and i cant smell a thing Rating: 5