First off, it wouldn't be just any African-Americans, it would be criminal gang members and their families. And prisoners can definitely be expelled, such as reg. https://en.wikipedia.org/wiki/Convicts_in_Australia . And there is historical precedents for expulsions, such as https://en.wikipedia.org/wiki/Expulsion_of_the_Moriscos . You are right that various Sub-Saharan African countries would be unlikely to be interested in that, but it ought to be possible to figure something or another out. Liberia was tried out, after all, though that was definitely not a success, given the cannibal warlords in Liberia (see some interviews with former cannibal warlords of Liberia as part of a documentary here: https://www.youtube.com/watch?v=ZRuSS0iiFyo ).
First off, it wouldn't be just any African-Americans, it would be criminal gang members and their families. And prisoners can definitely be expelled, such as reg. https://en.wikipedia.org/wiki/Convicts_in_Australia . And there is historical precedents for expulsions, such as https://en.wikipedia.org/wiki/Expulsion_of_the_Moriscos . You are right that various Sub-Saharan African countries would be unlikely to be interested in that, but it ought to be possible to figure something or another out. Liberia was tried out, after all, though that was definitely not a success, given the cannibal warlords in Liberia (see some interviews with former cannibal warlords of Liberia as part of a documentary here: https://www.youtube.com/watch?v=ZRuSS0iiFyo ).