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.

Adsorption and Assembly of Cellulosic and Lignin Colloids at Oil/Water Interfaces

“…A main emphasis of our work is the introduction of plant-based colloids in the stabilization of multiphase systems, particularly the emulsion’s oil/water interfaces. The associated processes and the state of dispersion are principally regulated by the nature of the colloidal particles and the conditions of the surrounding medium as well as the presence of dissolved substances . At the oil/water interface, ionic strength and pH affect the surface charge of the adsorbed particles, defining the activity and the stability of the multiphase system, which can be further tailored by steric interactions, especially in the presence of adsorbed, soft polymeric layers …”

Toxicity of GO to Freshwater Algae in the Presence of Al2O3 Particles with Different Morphologies: Importance of Heteroaggregation

“…Particles with different morphologies can have distinct colloidal properties and toxicity. , We thus selected three types of Al 2 O 3 particles (NPs, bulk particles (BPs), and fibers) as model minerals in the present work. The main objectives were to investigate (1) the effect of Al 2 O 3 particles with different morphologies on the toxicity of GO to freshwater algae; (2) the mechanism for the heteroaggregation-induced toxicity change; and (3) the roles of NOM and exposure sequence in GO-Al 2 O 3 heteroaggregation and related toxicity.…”

The effect of particle rotation on the motion and rejection of capsular particles in slit pores

“…15 We, and others, have been interested in the effect of bacterial shape and flexibility on rejections from membrane filters. [19][20][21] It has been demonstrated that particle size, shape, and surface properties can play a role in nanoparticle separations and in their detection and environmental fate. 14,16 The impact of particle shape on transport in porous media and in attachment to environmentally relevant surfaces has also been studied.…”

“…14,16 The impact of particle shape on transport in porous media and in attachment to environmentally relevant surfaces has also been studied. [19][20][21] It has been demonstrated that particle size, shape, and surface properties can play a role in nanoparticle separations and in their detection and environmental fate. 22,23 The rejection coefficient is a transport parameter characterizing solute rejection from a porous membrane and is defined by considering particle flux through the membrane, N s , relative to particle flux in an unbounded fluid: 24…”