Adsorption of Metal Ions and Metal Complexes on Clay Minerals: A Study of the Nature of Bonding by X-Ray Photoelectron Spectroscopy

摘要

Results are reported of an investigation of the interaction of metal ions, metal ion complexes, and organic ligands with mineral and metal ion-saturated surfaces. Minerals studied include those with oxidizing and nonoxidizing surfaces (for example, lead, cobalt, kaolinite, nickel, copper), selected as being typical of those with which metal ions and organic-metal complexes would interact. The purpose was to provide detailed chemical descriptions of the nature of the surface species. Surface characterization includes x-ray photoelectron spectroscopy, electrophoretic mobility, and infrared and visible spectroscopy. Results describe the chemical oxidation state of the adsorbed metal, the chemical stoichiometry of the surface adsorbates, and the chemical nature of the adsorbed ions. Evidence indicates that metal complexes interact with clay mineral surfaces via dissociative hydrolytic process. On the other hand, metal ion and metal ion complexes are oxidized when adsorbed on the MnO2 surface. Probable reactions processes for the dissociative hydrolytic processes are presented.