If it is still listed on your Home page, swipe left across the title and tap the red Archive button that appears.
To remove it from your Archived Items page you will need to log onto your Amazon.com account and go to the Manage Your Kindle. It should appear as a tab under the search bar, after you go to the Kindle Store. Near the bottom you'll find a list of titles under Your Orders. If you have more books than listed and can't see your title use the search or next page options.
To the left of each title is a small plus symbol. If you click on that you get a Delete this title option, among others.
After you've deleted it you'll need to go back to your iPad, go to the Archive Items page and refresh it. That would be the recycle style icon in the lower right of the screen.
I don't guarantee this will work. I haven't tested it, and don't have any books I'm willing to delete just to test the theory. But I think it will do the trick.