Before returning loanable iPad to the Library IT Help Desk, you should remove all personal information from it and reset the iPad to its original setting. This can be done in two simple steps.
Tap Settings, the default setting is General, from the right side of the screen scroll down to the end of the list, and select Reset.
There are six reset options, tap "Erase All Content and Settings" (second option from the top).
After all settings and content being erased, the iPad displays this screen that asks you to connect the iPad to a computer with iTunes:
Find a computer with iTunes or download iTunes to your computer. First, connect iPad to the computer, then launch iTunes, wait a little till you see iPad showing under "DEVICES" in the left pane.
All you need to do is to click the Eject icon, the iPad will return to the home screen (or lock screen which you can slide the button to unlock). The iPad is ready to be checked out by the next user.