You can submit a new adoption request, but be sure to read the reason staff gave for rejecting the first one. If nothing changes with your second request, they may reject that, too, for the same reason.
Usually, a wiki's admin gets to decide who should be moderator. Sadly, this wiki's admin has not been around for a long time, and so there is no one in charge of it.
There are a few options. If you'd like to be in charge of the wiki in general and become its new admin, you can look into adopting it.