(37b) Controlled Particle Deposition by Design of an Electrochemical Adsorption Cell

Deposition of colloidal particles substrate is encountered in a variety of naturally occurring processes such as particulate fouling of heat exchangers, thrombus formation in vascular prostheses and other artificial organs and aerosols entering the lungs. Deep bed filtration of waste waters is perhaps the most prominent example of importance to industry. Design of an electrochemical adsorption cell utilizing reticulated vitreous carbon (R.V.C.) as the working electrode ,stainless steel as the counter electrode and a cellulose acetate membrane ,for separating the anodic and cathodic, is described for the separation of 5.4 m polystyrene latex colloidal particles from a KCI solution. The experimental results are compared with the Derjaguin-Landau-Verwey-Ovdrbeek (D.L.V.O.) prediction for the occurrence of favorable and unfavorable deposition conditions. In the theoretical section of this work it will be assumed that the main energies contributing adsorption interaction between the surfaces will be due to electrical double layer to Van der Waals attraction. The some of these energies provides the total interaction energy between surfaces and this constitutes the underlying assumption for the classical D.L.V.O. theory of colloidal stability. The polystyrene latex particles used in this study were 5.4 µm and hence effect of diffusion becomes negligible. For reasonably low flow rates, Re