there are two methods you would rather try:
1. bubbling chlorine gas into a solution of iodide salts. the more conc the solution the better your results. careful with the chlorine tho; do it outside or in a fume cupboard and try to make it so the chlorine has nowhere to go EXCEPT the solution
2. acidifying the iodide with (20-30%) sulfuric acid preferrably (DO NOT USE HALIDE ACIDS...unless it's HI...but not like that's happening or anything) then oxidizing your iodide to iodine by adding a strong oxidizing agent, prefferably (40-60%) hydrogen peroxide. be careful to calculate everything stoichiometrically lest you create a bunch of peroxymonosulfuric acid and burn your hands off. also, add the peroxide slowly, as doing it too quickly could cause it to blow up