1. There is no way to merge Apple ID's. For more info, read this: http://support.apple.com/kb/HT5622
2. To sync contacts(or other data like Calendars) with iCloud on two different iOS devices is possible only if you're logged in with the same Apple ID on both devices. This means you have to either choose one of the Apple ID's and merge the contacts to iCloud (see below for instructions) or keep using both Apple ID's without merging the contacts.
If you don't mind having all the contacts on one iCloud account, do the following:
Go to Settings - iCloud on your iPad and choose Remove Account. Then, click 'keep data on iPad' when the question appears. The contacts will from your work will still be on the iPad.
Then, log in with your personal Apple ID at Settings - iCloud and choose 'merge/combine with iCloud' when it's asked. All contacts will end up on your personal Apple ID and then you can stop using the work ID.
More information on iCloud accounts: http://support.apple.com/kb/HT4436
Hope this helps 🙂
Good luck!
Stijn
Message was edited by: jesterwylde