Oxide-water interface, surface chemistry

In order to understand the surface chemistry at a solid oxide/water interface, high-temperature electrokinetic studies should be carried out. Recently, micro-electrophoretic studies of the ZrC>2- and TiC>2-water suspensions to 200 °C showed that such measurements are possible, but substantial effort will be needed to extend these measurements to a temperature range above 300 °C. In addition, a possibility to study nanoparticulate aqueous suspensions at high temperatures would be very beneficial. 

Surface chemistry of the oxide-water interface is emphasized here, not only because the oxides are of great importance at the mineral-water (including the clay-water) interface but also because its coordination chemistry is much better understood than that of other surfaces. Experimental studies on the surface interactions of carbonates, sulfides, disulfides, phosphates, and biological materials are only now emerging. The concepts of surface coordination chemistry can also be applied to these interfaces. This chapter is designed... 

To what extent can our concepts of the coordination chemistry of the oxide-water interface and our knowledge of the factors that enhance and retard dissolution of Fe(III) oxides contribute toward an understanding of the properties of passive iron oxides A review of the corrosion literature yields much phenomenological information that could be accounted for by surface-chemical theory. However, present passivity theories appear, with few exceptions, to be rather oblivious to the concepts of chemical surface reactivity. Thus, some perhaps speculative chemical ideas on the factors that enhance or reduce iron oxide passivity may be exposed to examination and discussion. 

Stone TA, Morgan JJ (1987) Reductive dissolution of metal oxides. In W Stumm (ed) Aquatic surface chemistry Chemical processes at the particle water interface. WUey, New York pp 221-254... 

Stumm, W. and Furrer, G. (1987) The solution of oxides and aluminium silicates examples of surface-coordination-controlled kinetics. In Aquatic Surface Chemistry Chemical Process at the Particle-Water Interface (ed. Stumm, W.). John Wiley and Sons, New York. 

Although the evolution of surface chemistry depicts the hydration of bare surfaces, the same process occurs for buried interfaces within an adhesive bond. This was first demonstrated by using electrochemical impedance spectroscopy (EIS) on an adhesive-covered FPL aluminum adherend immersed in hot water for several months [42], The EIS, which is commonly used to study paint degradation and substrate corrosion [43,44], showed absorption of moisture by the epoxy adhesive and subsequent hydration of the underlying aluminum oxide after 100 days (Fig. 5). At the end of the experiment, aluminum hydroxide had erupted through the adhesive. 

The formation of a layer of low molecular weight, oxidized material (LMWOM) on the surface of PP and PET films after CDT is widely accepted [10]. It is the effect of the material on adhesion that is debated. The formation of a weak boundary layer may be beneficial or detrimental to adhesion, depending on its solubility in the adhesive matrix. If the layer is soluble in the matrix, no decrease in adhesion may be observed. If, however, the layer is not soluble, this may reduce adhesion due to the presence of this cohesively weak layer at the interface. Water washing experiments were carried out to evaluate the effect of LMWOM on the surface chemistry and morphology. XPS and AFM... 

Dzombak DA, Morel FMM (1990) Surface complexation modeling. Hir-dous ferric oxide. Wiley, New York Stumm W (1992) Chemistry of the solid-water interface. Wiley,... 

Understanding the adsorption of long-chain alkyl amines and their surface structure is significant for improved nonsulfide flotation technology and the development of new flotation chemistry for the flotation of nonsulfide minerals. In the middle of the twentieth century, Gaudin and Fuerstenau first studied the use of long-chain alkyl amines for the flotation of oxide minerals, particularly the flotation of quartz with primary dodecylamine (DDA) (Gaudin and Fuerstenau 1955). Their studies showed that the collector adsorption density and zeta potential at the solid-water interface are... 

Schindler PW, Stumm W. The surface chemistry of oxides, hydroxides and oxide minerals. In W. Stumm (Ed.), Aquatic Surface Chemistry Chemical Processes at the Particle-Water Interface. Wiley, New York, 1987, p. 83. 

The specific type of surface active pyrrole derivative used to form the monolayer was found to strongly influence the chemistry that is initiated at the air-water interface. For example, when solutions containing a 5000/1 mole ratio of pyrrole/3-octadecylpyrrole were spread onto the oxidizing subphase, copolymerization of the two monomers occurred as well as homopolymerization of the unsubstituted pyrrole monomer. The net result was a relatively thick surface film (100-200A) that was very difficult to transfer into multilayers via a conventional vertical lifting technique. With 3-octadecanoylpyrrole as the surface active component, on the other hand, copolymeiization of the two monomers was suppressed and only electrically conducting polypyrrole chains were formed. In this latter case, uniform monolayer films about 40 A thick were formed and these could be readily transferred into multilayer structures. The chemical structures of the molecules used in this particular system are presented in Scheme 3. 

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