The　adsorption　of　iodine　anions　(iodide　and　iodate)　on　the　sulfur　terminated　(001)　chalcopyrite　surface　has　been　systematically　investigated　combining　first-principles　calculations　based　on　density　functional　theory　(DFT)　with　X-ray　photoelectron　spectroscopy　(XPS)　measurements.　Based　on　the　total　energy　calculations　and　geometric　optimization,　the　thermodynamically　preferred　site　was　copper　atom　for　iodide　adsorption　and　iron　atom　for　iodate　adsorption,　respectively.　In　the　case　of　Cu　site　mode,　the　iodate　underwent　a　dissociative　adsorption,　where　one　I-O　bond　of　iodate　ion　was　broken　and　the　dissociative　oxygen　atom　adsorbed　on　the　adjacent　sulphur　site.　Projected　density　of　states　(PDOS)　analysis　further　clarified　the　interaction　mechanism　between　active　sites　of　chalcopyrite　surface　and　adsorbates.　In　addition,　full-range　XPS　spectra　qualitatively　revealed　the　presence　of　iodine　on　chalcopyrite　surface.　High　resolution　XPS　spectra　of　the　I　3d　peaks　after　adsorption　verified　the　chemical　environment　of　iodine.　The　binding　energies　of　618.8　eV　and　623.5　eV　for　I　3d(5/2)　peaks　unveiled　that　the　adsorption　of　iodide　and　iodate　ions　on　copper-iron　sulfide　minerals　was　the　result　of　formation　of　low　solubility　metal　iodides　precipitate.　Also　two　I　3d　peaks　with　low　intensity　around　618　eV　and　630　eV　might　be　related　to　the　inorganic　reduction　of　iodate　to　iodide　by　reducing　S2-　ion　of　chalcopyrite.　(C)　2016　Elsevier　B.V.　All　rights　reserved.