Date of this Version
Delon, Thompson. Impact of Particle Surface Charge Heterogeneity on Deposition onto Flat Surfaces and Transport in Porous Media.2021.University of Nebraska-Lincoln, PhD Dissertation.
Biological and non-biological natural colloids are anisotropic and ubiquitously exist in groundwater. Previously in colloid transport modelling, colloids are assumed to be homogenous for simplification, whether in shape or surface charge. More research has been done to incorporate surface heterogeneity in the transport experiment, i.e., surface charge heterogeneity on collector in column experiment. However, few studies have been done on surface heterogeneity on colloids themselves.
In this dissertation, Janus particles with different surface charge was developed to model surface heterogeneity on colloids. The interaction energy between Janus particle and flat surfaces was analyzed through DLVO simulation. It was discovered that there is sensitivity region on Janus particle and the orientation of Janus particle approaching the flat surface will greatly impact the interaction energy. The simulation also showed that average zeta potential may lead to incorrect deposition prediction. The impact of particle surface heterogeneity on deposition onto flat surface was done using QCM-D. The deposition trend is greatly impacted by the polymer used to develop Janus particles.
Another contribution of this work is to investigate the impact of particle surface heterogeneity on particle deposition in porous media models. Porous media was
developed using microfluidic channel with a variety of collector geometry. Janus particles attached on collector’s surface were imaged using confocal microscope. Factors impacting the deposition of Janus particle on different collector geometry were investigated through DLVO simulations and computational fluid dynamic (CFD) model. The deposition of Janus particle in porous media was found to be impacted by the orientation of the particle approaching the surface of the collector and collector geometry.
Advisor: Yusong Li