A SERS Study of the Interaction of n-Octanohydroxamate with a Copper Electrode

SERS spectroelectrochemical investigations have demonstrated that the flotation collector n-octanohydroxamate specifically adsorbs on copper surfaces in the region of thermodynamic stability of the metal and, at low ionic strength, this gives rise to a contact angle of ~ 70{degree sign}. The contact angle fell to zero when Cu2O was formed on the copper surface and increased again to ~ 70{degree sign} when the potential was increased further. Voltammetry established that, in 0.01 M KOH, the presence of hydroxamate in concentrations of 10-3 M and above retards the rate of formation of Cu2O and indicates that a stability zone of copper n octanohydroxamate replaces that of hydrated CuO. It is concluded that the development of a copper n octanohydroxamate layer is responsible for the copper oxide surface being rendered hydrophobic at high potentials. SERS investigations of the copper/hydroxamate system is considered not to be an appropriate model for advancing understanding of the interaction of this collector with oxidized mineral surfaces.