SouSTAR is right, you can just upload both and the ratings will separate them. If someone wants to see or avoid only adult stuff then they can use the E,T,M,A filters.
But if you really want to have this as a dedicated account for NSFW, you can create an alt for your SFW art.
SouSTAR
Why not just uploading both SFW and NSFW? You just have to rate them properly so nobody will complain :)