This volcanic powder is described to be negatively charged, attracting odours and other contaminants from the air (opposed to baking soda's absorbent property which doesn't actively attract offensive odour particles):
Most floating contaminates such as odors and allergens are positively charged, and of course, negative ions are negatively charged. In environments where high densities of negative ions exist, they are able to reverse the charge of floating contaminates to a negative charge.
This results in a magnetic attraction among the floating pollutants in the air, causing them to aggregate, or “neutralize” one another.
Basically this is a $3.99 version of those expensive "ionic" devices without all the negative health concerns and a much more affordable price. If it works anything like zeolite or better, this might be a good fridge and litter companion we'd be willing to give a try, especially since it's "rechargeable"; just let is sit in a fresh air area to release all the stink it sucked in. And we certainly like that MultiFresh is not only all-natural, but the packaging is comprised of 100% recycled paper.