title: The attachment of colloidal particles to environmentally relevant surfaces and the effect of particle shape.
abstract: Despite the prevalence of nonspherical colloidal particles, the role of particle shape in the transport of colloids is largely understudied. This study investigates the attachment of colloidal particles onto environmentally relevant surfaces while varying particle shape and ionic strength. Using quartz crystal microbalance and atomic force microscopy measurements, the role of particle shape was elucidated and possible mechanisms discussed. The attachment of both spherical and stretched polystyrene colloidal particles onto a smooth alginate-coated silica surface showed qualitative agreement with DLVO theory. Attachment onto a Harpeth humic acid (HHA) surface, however, significantly deviated from DLVO theory due to its high surface heterogeneity and extended confirmation from the silica surface. This extended confirmation provided increased potential for spherical particle entanglement, while the enlarged major axis of the stretched particles hindered their ability to attach. As ionic strength increased, the HHA layer condensed and provided less potential for spherical particle entanglement and therefore the selectivity for spherical particle attachment vanished. The findings presented in this study suggest that colloidal particle shape may play a complex and important role in predicting the transport of colloidal particles, especially in the presence of natural organic matter-coated surfaces.
authors: Land, Air, and Water Resources, University of California Davis, Davis, CA 95616, USA; Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, USA.
authors: Coy P
authors: CP
authors: McNew
authors: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors: Negin
authors: N
authors: Kananizadeh
authors: Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
authors: Yusong
authors: Y
authors: Li
authors: Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, USA. Electronic address: eugene.j.leboeuf@vanderbilt.edu.
authors: Eugene J
authors: EJ
authors: LeBoeuf
mesh_terms: D000464:Alginates; D003102:Colloids / Q000737:chemistry*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D006812:Humic Substances / Q000032:analysis*; D018625:Microscopy, Atomic Force / Q000379:methods; D008863:Microspheres; D008962:Models, Theoretical; D009994:Osmolar Concentration; D010316:Particle Size; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods; D012822:Silicon Dioxide; D013499:Surface Properties
chemical_list: D000464:Alginates; D003102:Colloids; D006603:Hexuronic Acids; D006812:Humic Substances; D012822:Silicon Dioxide; D020723:Glucuronic Acid
keywords: Attachment; Colloid shape; NOM; QCM-D; Transport