My house at one time was a duplex. The kitchen no longer exists upstairs but all the plumbing remains including the ugly black vent pipe which is in the middle of the basement making it completely unusable. Can I remove the pipe and if so what do I use to cover where it connects into the main drain which is under concrete?

Cut it flush with the floor, tightly stuff newspaper in the opening, about 2-3 " down. Then mix up some hydraulic cement and fill the hole. You don't need to go to the main drain.