Evidence of two adsorption phases of 5-methyl-2-mercaptobenzoxazole on Cu2S by synchrotron radiation photoemission

Synchrotron radiation excited photoemission spectroscopy studies have been carried out on 5-methyl-2-mercaptobenzoxazole adsorbed on the surface of Cu2S. This paper reports one of the first applications of synchrotron radiation excited photoemission spectroscopy in the held of mineral processing investigations. S 2p and O 1s spectra for Cu2S surface after immersion in 5-methyl-2-mercaptobenzoxazole solutions at different concentrations (10(-6) M and 10(-5) M) and different contact times (1 min and 15 min), together with those for Cu2S cleaved in an ultra high vacuum are presented and discussed. The use of the synchrotron photon source permits investigation of the real first stage of adsorption, because of the high surface sensitivity of the technique. The presence of two 5-methyl-2-mercaptobenzoxazole species on the Cu,S surface has been revealed by the fitting procedure. The attribution of the two species and how their structure changes with the experimental parameters are discussed. (C) 1997 Elsevier Science B.V.