SQL Server recovery model cannot be changed
To change the recovery model requires the ALTER permissions on the database. You can revoke or deny that permission to a user and it will prevent them from altering the recovery model.
Note that denying permissions overwrites any grants, ensure you test any permissions changes before applying to a production server!

Required permissions
Requires ALTER permission on the database.

Ref: https://msdn.microsoft.com/en-au/library/ms189272(v=sql.120).aspx