The Effects of Substrate Heterogeneity on Colloid Deposition

• Author / Creator

  Kemps, Jeffrey A L

• Heterogeneity of surfaces is often included in mathematical treatments of colloid transport and deposition as an afterthought, if at all. Most previous models of colloid transport and deposition have employed idealizations and simplifications such as assuming smooth collector surfaces with uniform chemical properties. This research proposes a new heterogeneous interaction model (HIM) to account for colloidal forces between particles and heterogeneous substrates. Extending the approach employed with the HIM, the inclusion of convection and diffusion in the model leads to a Lagrangian particle tracking model (PTM) for predicting colloid transport and deposition on a planar substrate containing one or more protruding asperities in the presence of shear flow. An important part of the PTM is an accurate rendering of the fluid flow field around the model substrate, which is obtained from a numerical solution of the Stokes equations. A simple approximation of the particle-substrate hydrodynamic interactions was developed for the PTM based on the universal hydrodynamic correction functions. This model was employed to quantitatively predict how presence of asperities on a collector can influence the deposition of particles on the substrate in shear flow. Flow field modifications due to the substrate's physical heterogeneity -- coupled with hydrodynamic interactions -- and the lateral migration (colloidal) forces near chemically heterogeneous substrates yield remarkably diverse deposition probabilities and deposit morphologies. The general approach of this research, which involves the use of the HIM in conjunction with the Brownian PTM, results in the first simulation tool of its kind to attempt to quantify deposition on heterogeneous substrates.

• Subjects / Keywords

  • Particle
  • Brownian
  • DLVO
  • Interactions
  • Models
  • Hydrodynamics
  • Lagrangian
  • Simulations
  • Heterogeneity
  • Deposition

• Graduation date

  Spring 2010

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3KW6C

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.