I did not write in the lease agreement to give me 30 days notice before you plan to move. The tenants want to move out in 14 days, do I have to return deposit by Georgia law

Is this a lease ( like for 6 months or one year) or is it a month to month rental.
If it is a real lease, they can not move out till the terms of the lease is over.

If it is a month to month rental, that is different,

Please tell us more about he agreement ?

If the lease does not specify the amount of required notice, then state law applies. If the lease specified an ending date, then they are responsible for the balance of the lease. If it is a tenancy at will (the lease has no expiration date or expired) then they are required to give 30 days notice.

So they can move in 14 days, but you can withhold part of the security deposit to cover the balance of the 30 days. You will have to given then an accounting of how you used the deposit according to the law.

http://www.dca.ga.gov/housing/HousingDevelopment/programs/downloads/Georgia_Landlord_Tenant_Handbook.pdf