Density-functional theory of xanthate adsorption on the pyrite FeS2(100) surface

We have used the density-functional theory (DFT) method with a plane wave-pseudopotential basis to compute the structure and properties of a model xanthate molecule (HOCS2- ) and its adsorption characteristics on the (100) surface of pyrite (FeS2). Results from DFT calculations suggest that HOC2- by itself does not readily adsorb on the (100) surface. However, adsorption of a xanthate-Fe-hydroxide complex species on the surface Fe site is energetically favourable, and this is consistent with experimental results which indicate that adsorption of such a molecular complex is likely to be one mechanism responsible for collector-induced surface hydrophobation of real FeS2 surfaces.