Colloid transport

Abstract

Colloid transport in porous media plays important roles in many agricultural, environmental, and engineering processes. Colloids vary in their source, composition, shape and structure but they all possess large specific surface areas and have high reactivity. Deposition or attachment, release or detachment, and straining are the processes controlling colloid transport in saturated media; attachment to air-water interfaces and the contact line, and film straining are additional processes affecting colloid transport through unsaturated media. The interactions of colloids with interfaces can be described by classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, which considers van der Waals and electrical double layer forces and by extended DLVO, which includes non-DLVO forces (e.g., hydration, steric and hydrophobic). Current approaches to modeling colloid transport build on the classical colloid filtration theory. More complete mechanistic understanding of colloid retention and release processes and experimental validation will improve model development and our ability to manage both the risks and beneficial applications of environmental colloids.