Adsorption mechanism of 2-mercaptobenzothiazole on chalcopyrite and sphalerite surfaces: Ab initio and spectroscopy studies

Interaction mechanism of the collector, 2-mercaptobenzothiazole (MBT), with chalcopyrite and sphalerite surfaces were investigated by Fourier transform infrared (FTIR) and density functional theory. Results of FTIR showed that some characteristic peaks of MBT were observed on the chalcopyrite surface, including C=N, C=N—S and C—S stretching vibration peaks, and the adsorption product was CuMBT. But there were no characteristic peaks of MBT on the sphalerite surface. The thione molecular form of MBT was the most efficient and stable, N and exocyclic S were the more favourable reactive sites for nucleophilic attacked by metal atoms. Compared with ZnS (110), MBT is more readily adsorbed on CuFeS2 (112). Attachment of MBT occurs due to strong bonding through exocyclic S p and s orbits with Cu d orbit on CuFeS2 (112) and electron transfer from Cu atom to S atom. Under the vacuum condition, MBT in the form of thione molecular cannot be adsorbed on ZnS (110) spontaneously.