Sulphide interfacial

Opinions differ on the nature of the metal-adsorbed anion bond for specific adsorption. In all probability, a covalent bond similar to that formed in salts of the given ion with the cation of the electrode metal is not formed. The behaviour of sulphide ions on an ideal polarized mercury electrode provides evidence for this conclusion. Sulphide ions are adsorbed far more strongly than halide ions. The electrocapillary quantities (interfacial tension, differential capacity) change discontinuously at the potential at which HgS is formed. Thus, the bond of specifically adsorbed sulphide to mercury is different in nature from that in the HgS salt. Some authors have suggested that specific adsorption is a result of partial charge transfer between the adsorbed ions and the electrode. 

The interfacial galvanic interactions of sulphide minerals in the grinding system are affected by hitting or erasing force resulting in the formation of... 

Chander, S. and Fuerstenau, D. W., 1975. Sulphide minerals with thiol collectors the chalcocite diethy dilhiophosphate system. 11th International Mineral Processing Congress, 1 583 - 603 Chander, S., Wie, J. M., Fuerstenau, D. W., 1975. On the native floatability and surface properties of naturally hydrophobic solids, hr P. Somasunfaran and R. G. Grieves(eds.), Advances in Interfacial Phenomena of Particulate/Solution/Gas Systems. AIME Symp., Ser., 150(71) 183-188... 

Rand, D. A., 1975. Oxygen reduction on sulphide minerals, part III comparisson of activity of various copper, iron, lead, nickle mineral electrodes. Electrochemistry and Interfacial Electrochemistry, 60 265 - 275... 

Other effects that have been reported, such as the positive effect of adding a cobalt metal-organic adhesion promoter to the rubber compound, have been shown to be related to modifications of the interfacial sulphide film. 

Figure 6.1 Mechanism of rubber-brass bonding after van Ooij [4], Shown are a) the original brass surface composition and, b) the interfacial copper sulphide dendrites interlocked with the crosslinked rubber compound (Reprinted with permission, from W. J. van Ooij, Rubber Chemistry and Technology, 1984, 57, 3, 426, Figure 1 and 445, Figure 11. 1984, Rubber Division, American Chemical Society, Inc.)...

Waddell did some work on the changes in the interfacial layers [41]. A wide range of surface-analytical tools were used Auger electron spectroscopy (AES), x-ray photoelectron spectroscopy (XPS), SEM, EDX, and particle indnced x-ray emission (PIXE), which indicated that silica use reduced the thickness of the interfacial film, and particularly promoted zinc oxide formation and lowered the amount of sulphide formed. 

Some miscellaneous publications are summarised here. It was reported by Matyukhin that the bond between brass-plated tyre cord and rnbber can be broken electrochemically [65]. The process results in a growth in the interfacial layer of zinc hydroxide which dislodges the sulphide film. The method appears useful for recycling purposes, but it was also reported to be useful for assessing the strength of the cord-rubber bond. 

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