Ionic transport Processes

Descripción

Transport phenomena constitute an integral part of electrode and membrane processes. Electrode reactions are heterogeneous and take place on the electrode surface, thus creating concentration differences in the electrode vicinity, and these differences cause mass transport. In membrane processes, analogous surface phenomena occur in many cases, but in addition, transport processes inside the membrane phase can also be decisive. The characteristic feature of the information obtained from a transport phenomenon is that measurable quantities represent integral values over the entire surface under study. This means that in, e.g., electrode processes, only the response function of the chosen perturbation function that has been fed into the system can be measured. In some cases, however, it is possible to get complementary spectroscopic information of the surface. When modelling a heterogeneous process, transport phenomena are of great importance but they alone do not describe the entire process sufficiently.Various surface phenomena and reactions must be included in the model. And it has to be realized that the study of these surface phenomena, e.g. adsorption, is possible only after the solution of the inherent transport problem and after the subtraction of its effect on the entire process. Thus, a comprehensive model of a heterogeneous process is mathematically rather demanding.

Detalles

Otros Libros de "Ingeniería Quimica"