Physicochemical aspects of colloid deposition in a rotating disk system: implications for contaminant transport
AuthorCramer, Michael Christian
Committee ChairSáez, Eduardo
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractApplication of conventional theory of transport and deposition to small particles or large colloids, on the order of 1 micron in diameter, has received surprisingly little attention in colloid science. While the favorable deposition of colloidal particles ( < 0.5 micron diameter) has repeatedly been shown to agree with the Smoluchowski-Levich approximation for a convective-diffusion process, larger particles are known to deviate from this solute-like mass transfer behavior. The rotating disk, used in the experiments performed in this work, is a model experimental system that has been employed in the past to de-convolute and quantify the mechanisms of particle transport. Experimental evidence shows that particle transport to the rotating disk deviates from the predictions of the complete three-dimensional convective-diffusion equation, including hydrodynamic and surface-surface interaction forces, in that non-uniform deposition is observed over the surface of the disk. Fluid inertial effects, observed to be significant in capillary flow, have been suggested in the literature as an explanation of non-uniform deposition on the rotating disk. Calculations performed in this work show that while inertial lift forces are significant, they are not the dominant cause of non-uniform deposition. Instead, hydrodynamic blocking of available deposition surface area is shown to accurately describe experimental deposition profiles. The effect of particle size on surface area exclusion and hydrodynamic scattering are separately assessed to demonstrate that the blocking model is not only phenomenologically accurate, but also an important part of the mechanistic description of transport in the rotating disk system.
Degree ProgramChemical Engineering