Diatomaceous earth is the ground skeletons of plankton. It has very sharp edges (but looks to us like a powder) and theoretically the bugs will walk across it and it scrapes their skin and they dehydrate.
Once wet, though, it forms a paste and doesn’t harm anything. I used it last year (nice and dry) indoors to try to kill ants and it didn’t do anything. Some people swear by it but it’s said to harm humans and chickens if we inhale it. Not for me, thanks.
I can’t imagine bentonite would do anything but perhaps help firm up diarrhea. Maybe.