Film Straining of Colloids in Unsaturated Porous Media: Conceptual Model and Experimental Testing | doi.page

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Film Straining of Colloids in Unsaturated Porous Media: Conceptual Model and Experimental Testing

Environmental Science & Technology1997Vol. 31(8), pp. 2413–2420

Citations Over TimeTop 11% of 1997 papers

Abstract

A film-straining theory is introduced, which proposes that transport of suspended colloids can be retarded due to physical restrictions imposed by thin water films in partially saturated porous media. A quantitative, mechanistic model is provided to predict the film-straining efficiency. In this model, the concepts of “critical matric potential” and “critical saturation” are introduced, at which thick film interconnections between pendular rings are broken and film straining begins to become effective. The modeled magnitude of colloid transport through water films depends on the ratio of colloid size to film thickness and on flow velocity. Effective penetration of hydrophilic colloids through unsaturated porous media is predicted when a system is above the critical saturation value. For colloids smaller than the thickness of adsorbed thin water films, the model predicts that colloids can still be efficiently transported, even when the system matric potential and saturation are lower than their critical values. The model was tested through experiments on transport of hydrophilic latex particles (four sizes from 0.01 to 1.0 μm) in sand columns of three different grain sizes and at flow rates spanning 4 orders of magnitude. The conceptual basis of this model is supported by good agreement between the wide range of experiments and model predictions using only two adjustable parameters.

Citations Over TimeTop 11% of 1997 papers

Abstract

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