Salicylaldoximes adsorption

SlOO proteins, 577 structure, 573 Saccharomyces cerevLsiae cation transport, 559 manganese transport, 570 Salicylaldimine copper(II) complexes, 156 Salicylaldoximes adsorption minerals, 782... 

A number of attempts have been made to understand the mechanism of the adsorption of chelates on oxide minerals. For instance, IR spectroscopic studies10 have indicated the presence of a basic monosalicylaldoximate copper complex as well as the bis-salicylaldoximate complex on the surface of malachite (basic copper carbonate) treated with salicylaldoxime. However, other workers4 have shown that the copper chelate is partitioned between the surface and dispersed within the solution, and that a dissolution-precipitation process is responsible for the formation of the chelate. Research into the chemistry of the interaction of chelating collectors with mineral surfaces is still in its infancy, and it can be expected that future developments will depend on a better understanding of the surface coordination chemistry involved. 

In mineral-reagent systems, surface precipitation has been proposed as another mechanism for chemisorption. The solubility product for precipitation and the activities of the species at the solid-liquid interface determine the surface precipitation process. Under appropriate electrochemical conditions, the activity of certain species can be higher in the interfacial region than that in the bulk solution and such a redistribution can lead to many reactions. For example, the sharp increase in adsorption of the calcium species on silica around pH 11 has been shown to be due to surface precipitation (Somasundaran and Anan-thapadmanabhan, 1985 Xiao, 1990). Similar correlations have been obtained for cobalt-silica, alumina-dodecylsulfonate, calcite/apatite/dolomite-fatty acid, francolite-oleate and tenorite-salicylaldoxime systems. The chemical state of the surfactant in the solution can also affect adsorption (Somasundaran and Ananthapadmanabhan, 1985). 

Several complexing ligands can be employed to determine copper in seawater. However, the best results are obtained when copper is determined after adsorptive pre-concentration as a complex with salicylaldoxime (SA) Campos and van den Berg, 1994). Analysis is carried out at neutral pH values (pH 6.5-8.5 is suitable) which means that the original sample pH can be maintained which is useful for speciation studies. 

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