I use bentonite clay for all sorts of things where I want to be able to absorb moisture without causing a mess.
Clean kitty litter/bentonite clay works great and is very cheap compared to other sources.
As long as you add other things to it, it will fall apart nicely.
The "liner" for ponds is usually pure bentonite spray, or otherwise used as a lone layer to keep
water in. .
As far as actual kitty litter? We use compressed pine bedding for horses. It's absorbent, smells nice for quite a long time considering, and is biodegradable. I use the used litter, complete with feline additions, as "hole filler" in my backyard where the
chickens scatter it all over. It's, slowly, improving our soil. I wouldn't recommend using as
compost, unless your pile reaches sterilizing temperatures. There can be nasty zoonotics that sneak up and make you ill..
(ed for spelling)