Surface enhanced raman scattering spectroscopic studies of the adsorption of flotation collectors

Abstract

Surface enhanced Raman scattering (SERS) spectroscopy at surfaces under electrochemical control has been applied to elucidate the adsorption of thiol collectors. Voltammetry has shown that charge transfer chemisorption of ethyl, isopropyl, isobutyl and isoamyl xanthates occurs on silver surfaces at potentials below the reversible value for the formation of the silver xanthate. SERS spectroscopy has identified the species formed at underpotentials to be xanthate bonded to silver atoms through the sulfur atoms. Application of this technique has also shown that the adsorption of O-isopropyl-N-ethylthionocarlpamate on copper involves a charge transfer process and rest potential measurements indicate that this adsorption occurs at underpotentials. SERS spectra also establish that 2-mercaptobenzothiazole undergoes charge transfer chemisorption on copper, silver and gold over a wide potential range by bonding through the exocyclic sulfur atom.