How To Measure Fractal Colloid Deposits in Porous Media

Abstract:

Flow and transport in natural and engineered porous media often depend on colloidal phenomena, that is, phenomena related to particles in the range of 1-10,000 nanometers. Examples include processing of colloidal suspensions, reactive transport in which colloidal precipitates are formed, and flow and transport in groundwater aquifers. In each of these systems, fundamental understanding is hampered by the difficulty in measuring the structure, or morphology, of colloid aggregates and colloid deposits in situ. This presentation describes a novel apparatus that measures the fractal dimension, radius of gyration, and (flow cell averaged) permeability of colloid deposits using static light scattering (SLS) through refractive index matched (RIM) porous media. This apparatus allows real-time measurement of colloid aggregate and deposit morphology as a function of depth within the flow cell. This apparatus should prove useful in any application requiring characterization of colloidal phenomena within porous media.