While you can't completely remove items from your iBooks purchased list, you can hide purchased items so that they do not appear in your list of purchased books.I can make them disappear from the book shelf, but not the purchased books shelf. Some of these books I do not wish others to see what I've read.
you could try deleting the app from your iPad, then downloading it again. See if that works.Ok, so tried all that. I did manage to remove, or hide, the purchase on the pc in iTunes, but cannot remove or hide these purchases in iBooks, even though there's an edit and delete button. I had the ipad synced and everything, but still no luck. Kinda frustrating.
If you don't want to see the purchased books in iBooks, go to Settings - iBooks and disable "Show all purchases", in case you haven't already done so.
****! Shoulda never "bought" those free books.In addition: they are still visible in iBooks Store - Purchased. When you tap "Store" in iBooks, you get there.