Does Water Content or Flow Rate Control Colloid Transport in Unsaturated Porous Media?

Knappenberger, Thorsten; Flury, Markus; Mattson, Earl D.; Harsh, James B.

doi:10.1021/es404705d

Cited by 57 publications

(42 citation statements)

References 67 publications

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“…transport of colloids, radioactive waste, bacteria, etc. through unsaturated soils (vadose zone) [117,127,128] or (thermal, electrical, etc.) conductivities in packed beds for technological uses [57,129].…”

Section: Equilibrium Interparticle Distancementioning

confidence: 99%

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

Gallego-Gómez

Morales‐Flórez

Morales

et al. 2016

Advances in Colloid and Interface Science

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Solid colloidal ensembles inherently contain water adsorbed from the ambient moisture. This water, confined in the porous network formed by the building submicron spheres, greatly affects the ensemble properties. Inversely, one can benefit from such influence on collective features to explore the water behavior in such nanoconfinements. Recently, novel approaches have been developed to investigate in-depth where and how water is placed in the nanometric pores of self-assembled colloidal crystals. Here we summarize these advances, along with new ones, that are linked to general interfacial water phenomena like adsorption, capillary forces and flow. Waterdependent structural properties of the colloidal crystal give clues to the interplay between nanoconfined water and solid fine particles that determines the behavior of ensembles. We elaborate on how the knowledge gained on water in colloidal crystals provides new opportunities for multidisciplinary study of interfacial and nanoconfined liquids and their essential role in the physics of utmost important systems such as particulate media.

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Section: Equilibrium Interparticle Distancementioning

confidence: 99%

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

Gallego-Gómez

Morales‐Flórez

Morales

et al. 2016

Advances in Colloid and Interface Science

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“…The variation of IS under natural conditions (e.g., rain or irrigation) does not always show a decreasing trend, thus, a single study only relating to IS reduction effect on particle mobilization and transport in soil is not sufficient. As regard to FR perturbation, most of literatures showed that particle release would be increased as FR increasing (Knappenberger et al 2014;Sasidharan et al 2014), whereas some have interesting and unique results varies from most of literatures. Tosco et al (2012) pointed that FR did not significantly influence the particle deposition at low IS, when particle deposition rates were low.…”

Section: Introductionmentioning

confidence: 96%

“…Colloidal particles (1 nm to 10 μm) can act as important transport vectors of contaminants in soil system (Bin et al 2011;Knappenberger et al 2014;Murali et al 2014). With a high specific surface and mobility, colloidal particles always provide a rapid transport pathway for the sorbed contaminants thereby facilitating the transport of contaminants in the soil (Zhu et al 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Long-term accumulated tailing wastes exposed to soil surface will naturally introduce masses of colloidal particles into surrounding soil under water erosion in many cases (Lower et al 2004;Slowey et al 2007;Slowey Responsible editor: Zhihong Xu et al 2005). More importantly, tailing particles always carrying mounts of toxic heavy metals, and can travel in the subsurface over longer distances at higher velocities than soluble metals due to size exclusion effects (Bin et al 2011;Grolimund and Borkovec 2005;Knappenberger et al 2014). It thus appears that the mobile tailing particles being rich in toxic metals will intensify the dissemination of heavy metals in soil, and the knowledge of transport of tailing particles in soil is essential for making an accurate assessment of heavy metal contamination in mining region.…”

Section: Introductionmentioning

confidence: 99%

“…Colloidal particle mobilization and transport in natural porous media often occur as a result of water physicochemical perturbations (Zhu et al 2014;Zhuang et al 2007), therein, changes in water ionic strength (IS) and flow rate (FR) are the major factors inducing particle mobilization and transport (Kanti Sen and Khilar 2006;Knappenberger et al 2014;Pham et al 2014;Slowey et al 2005). For mine tailings the investigation on colloidal particle mobilization and transport under transient IS and FR is particularly relevant, because the changes in pore-water IS and FR can be frequently triggered by rainfall or snowmelt water that move through the tailing piles, and then lead to tailing particle release (Lower et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions

et al. 2016

Environ Sci Pollut Res

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Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution.

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Role of air‐water interfaces in colloid transport in porous media: A review

Flury

Aramrak

2017

Water Resources Research

Self Cite

103

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Air‐water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air‐water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air‐water interfaces in porous media. We discuss the theory of colloid/air‐water interface interactions, based on the different forces acting between colloids and the air‐water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air‐water interface because most subsurface colloids and the air‐water are negatively charged. However, hydrophobic interactions can lead to attraction to the air‐water interface. When colloids are at the air‐water interface, capillary forces are usually dominant over other forces. Moving air‐water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air‐water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air‐water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air‐water‐solid interface line, causing colloid retention and immobilization. Air‐water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface chemistry.

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Does Water Content or Flow Rate Control Colloid Transport in Unsaturated Porous Media?

Cited by 57 publications

References 67 publications

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

Colloidal crystals and water: Perspectives on liquid–solid nanoscale phenomena in wet particulate media

Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions

Role of air‐water interfaces in colloid transport in porous media: A review

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