Electrokinetic behavior interfaces

Wiese, G.R. Healy, T.W. Coagulation and electrokinetic behavior of Ti02 and AI2O3 colloidal dispersions. J. Colloid Interface Sci. 1975, 51, 427-433. 

Hu YH, Lu YJ, Veeramasuneni S, Miller JD. (1997). Electrokinetic behavior of fluoride salts as explained from water structure considerations. Journal of Colloid and Interface Science 190 224-231. 

In conjunction with the above studies of the time-dependent interfacial tension behavior and the coalescence properties of water-in-Leduc crude oil emulsions, the electrokinetic behavior of oil droplets in aqueous media (reverse emulsion) was also studied in the presence of Duomeen C and Aerosol OT. It was hoped that this will provide additional information on the adsorption of material at the oil/water interface. 

Modifications of surface layers due to lattice substitution or adsorption of other ions present in solution may change the course of the reactions taking place at the solid/liquid interface even though the uptake may be undetectable by normal solution analytical techniques. Thus it has been shown by electrophoretic mobility measurements, (f>,7) that suspension of synthetic HAP in a solution saturated with respect to calcite displaces the isoelectric point almost 3 pH units to the value (pH = 10) found for calcite crystallites. In practice, therefore, the presence of "inert" ions may markedly influence the behavior of precipitated minerals with respect to their rates of crystallization, adsorption of foreign ions, and electrokinetic properties. 

The mechanism of interaction of amino acids at solid/ aqueous solution interfaces has been investigated through adsorption and electrokinetic measurements. Isotherms for the adsorption of glutamic acid, proline and lysine from aqueous solutions at the surface of rutile are quite different from those on hydroxyapatite. To delineate the role of the electrical double layer in adsorption behavior, electrophoretic mobilities were measured as a function of pH and amino acid concentrations. Mechanisms for interaction of these surfactants with rutile and hydroxyapatite are proposed, taking into consideration the structure of the amino acid ions, solution chemistry and the electrical aspects of adsorption. 

Lopez-Leon, T., Carvalho, E. L., Seijo, B., Ortega-Vinuesa, J. L., and Bastos-Gonzalez, D. (2005), Physicochemical characterization of chitosan nanoparticles Electrokinetic and stability behavior,/. Colloid Interface Sci., 283(2), 344-351. 

The study of the electrochemical behavior of peroxide has indicated two possible routes of elimination at the LaNi03-aqueous interface [81] electrochemical dismutation at low overvoltage and electroreduction at high overpotentials. Table 4 shows a comparison of electrokinetic data for several perovskite oxides. 

Use of Ultrasonic Vibration Potential To Monitor Coalescence. The complex chemical nature of crude oils makes it difficult to relate the dispersion behavior to the physicochemical properties at the crude-oil-water interface. In addition, the nonpolar and nontransparent nature of the oleic phase provides significant obstacles for studies of the interactions of the suspended water droplets in real systems. Recent development (28, 29) of electroacoustical techniques has shown considerable promise for electrokinetic measurements of colloidal systems and the direct monitoring of the rate and extent of coagulation (flocculation and coalescence) of water droplets in nontransparent water-in-oil media. The electroacoustic measurement for colloidal systems in nonpolar media is based on the ultrasound vibration potential (UVP) mode, which involves the applica-... 

Rudzinski, W. et al.. On the nature of the energetic surface heterogeneity in ion adsorption at a water/oxide interface The behavior of potentiometric, electrokinetic and radiometric data, Langmuir, 8, 1154, 1992. 

In many flotation systems, the electrical nature of the mineral/water interface controls the adsorption of collectors. The flotation behavior of insoluble oxide minerals, for example, is best understood in terms of electrical double-layer phenomena. A very useful tool for the study of these phenomena in mineral/water systems is the measurement of electrokinetic potential, which results from the interrelation between mechanical fluid dynamic forces and interfacial potentials. Two methods most commonly used in flotation chemistry research for evaluation of the electrokinetic potential are electrophoresis and streaming potential. 

As with electrokinetic phenomena, the existence of negative adsorption implies the existence of an electrified interface. The behavior of this interface toward charged particles can always be investigated with the help of a particular molecular model, such as DDL theory, but it is useful to see how much information can be obtained without a detailed model, in keeping wih the spirit of the previous sections in this chapter. Consider, for example, the application of thermodynamics to the prototypical two-chamber (experiment on negative adsorption. If the very small osmotic pressure created by the suspended soil clay is neglected, the activity of any electrolyte in the two chambers is the same in both the suspension and the supernatant solution ... 

In this paper the use of electroacoustic techniques involving the application of a sonic field and the detection of an electric field, for monitoring coalescence of water droplets in non-polar media will be discussed. This technique was used to evaluate the rate and extent of dewatering in oil continuous emulsions when surface active chemicals were added. The results showed that a combination of an oil soluble demulsifier and water soluble surfactant was substantially more effective in causing droplet coalesence than the individual components. An explanation for these findings were based on studies of time-dependent interfacial tensions at the oil/water interface and electrokinetic properties. The results indicated that a direct relationship exists between the adsorption behavior at the oil/water interface (apparent rate of spreading) and emulsion stability. 

Matsumoto, H., Yako, H., Minagawa, M., and Tanioka, A. (2007) Characterization of chitosan nanofiber fabric by electrospray deposition electrokinetic and adsorption behavior. /. Colloid Interface Sci., 310, 678-681. 

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