Potential flow interfacial force

The interfacial force constants available in the literature for many organic solutes that constitute potential pollutants in water enable one to calculate the separation of such solutes at various operating conditions by a membrane of a given average pore size and pore size distribution on the basis of the surface force-pore flow model. The product rate of the permeate solution can also be calculated. Such data further allow us to calculate the processing capacity of a membrane to achieve a preset ratio of concentration in the concentrate to concentration of the initial feed solution. 

An important subject in this chapter on Electron transfer at electrodes and interfaces is to draw an analogy between electrochemical and interfacial electron transfer between two solid phases. Any theory dealing with electron transfer has a thermodynamic and a kinetic basis. In Section 4.2, it was shown that electrons flow or tunnel in the direction of decreasing electrochemical potential the gradient of the electrochemical potential is the driving force behind a directed flow of electrons,... 

Figure 4-3. Electrochemical techniques and the redox-linked chemistries of an enzyme film on an electrode. Cyclic voltammetry provides an intuitive map of enzyme activities. A. The non-turnover signal at low scan rates (solid lines) provides thermodynamic information, while raising the scan rate leads to a peak separation (broken lines) the analysis of which gives the rate of interfacial electron exchange and additional information on how this is coupled to chemical reactions. B. Catalysis leads to a continual flow of electrons that amphfles the response and correlates activity with driving force under steady-state conditions here the catalytic current reports on the reduction of an enzyme substrate (sohd hne). Chronoamperometry ahows deconvolution of the potenhal and hme domains here an oxidoreductase is reversibly inactivated by apphcation of the most positive potential, an example is NiFe]-hydrogenase, and inhibition by agent X is shown to be essentially instantaneous.

Such a relative motion can be induced by external electric fields or by pressure gradients or bulk forces (e.g. gravity). It is possible that particles move in a quiescent solvent or that the solvent flows through a fixed bed of particles. A detailed description on electrokinetic phenomena is e.g. given by Hunter (1988). Zeta-potential measurements on colloidal suspensions are fiequently conducted via electrophoresis or by means of electroacoustics. Besides this, there are recent techniques based on non-linear optics that are sensitive to interfacial changes. 

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