you probably could, but it take a fair bit of frankenstein work.
first, you need to supply more than 12V to charge a 12V battery. More preciousely, you need about 14V.
second, you need a current regulator, otherwise your power adaptor would fry itself in a minute or less.
3rd, (not necessary) for the 'smart' charger feature, you need automatic cut off when battery reaches desired charge, top up every few days, and cycle the battery every week or two.