Mobilization of Attached Clustered Colloids in Porous Media

Abstract

The models for colloidal mobilization in porous media are often based on Derjaguin‐Landau‐Verwey‐Overbeek interaction energy profiles. Despite abundant evidence on mobilization of particle clusters, the models to date have been limited to single colloid‐surface Derjaguin‐Landau‐Verwey‐Overbeek calculations. We show through visualization tests, qualitative and quantitative modeling, and data evaluation, that the widely accepted single colloid‐single surface isolation does not always adequately describe colloid behavior. The experiments were performed with kaolinite and latex particles mobilized from sand grains and glass beads in a transparent visualization cell. The particles were mobilized under increasing velocity and pH and decreasing salinity. The detachment conditions were determined by a torque balance of electrostatic, drag, lifting, and gravity forces, combined with a theory of a contact area between a single soft particle and a plane surface. The tests show that the calculations based on the mechanical equilibrium of a single particle on a plane surface significantly underestimate the critical detachment velocity. A better prediction is obtained using a cluster approximation. High‐resolution images taken during mobilization tests show 2‐12 particle clusters on media surface and in its proximity. The mechanical‐equilibrium calculations show that the attaching torque for clusters with assumed size and cylindrical shape is significantly higher than that for single particles. The critical detachment velocity of clusters, derived from the mechanical‐equilibrium force and torque balances, is higher than for single particles and provides a better fit to the experimental data. Our study suggests that a cluster approximation can accurately predict the mobilization of colloids in porous media.

Fine Migration Control in Sandstones: Surface Force Analysis and Application of DLVO Theory

“…During early research studies and to date, a single fine particle of spherical shape on a sand grain flat surface (sphere–plate model) has been extensively used for the calculation of DLVO interactions because of the simplicity of the approach. ,,,,,− A few researchers have utilized a plate–plate model for the quantification of interaction energies. , The single sphere model can be accurately used for synthetic fines and glass bead configurations, but when it comes to natural kaolinite and sand grain configurations, it can provide erroneous results because natural kaolinite has a platelet structure and must be modeled with a kaolinite platelets–IT plate model. In some studies during the last few years, ,,− clustered fine particles’ detachment and combined movement were assumed instead of a single fine particle model.…”

“…In some studies during the last few years, ,,− clustered fine particles’ detachment and combined movement were assumed instead of a single fine particle model. Recently, Chequer et al used this new idea to show that the single-colloid single-surface system is not an accurate representation of colloidal behavior in porous media and significantly underestimates the critical velocity of the fluid to initiate the fine migration. Experimental results were in close agreement with the clustered fines model.…”

Colloid transport through soil and other porous media under transient flow conditions—A review

“…However, solution chemistry, grain size, pore flow velocity, and colloid concentration all influence the shape of the DLVO interaction energy curve, the magnitude of the energy barrier, and the depth of the primary and secondary minimum (Carstens et al, 2017; Liu et al, 2018; Rasmuson et al, 2019; Rastghalam et al, 2019; Xu et al, 2016; Yang et al, 2019) and with that the deposition efficiency of colloids from bulk solution. These parameters have also been found to control colloid detachment, the release of deposited colloids from the soil grain, which is dependent on the balance of repulsive forces between colloid and grain surfaces (Chequer, Bedrikovetsky, Carageorgos, Badalyan, & Gitis, 2019; Ma et al, 2016; Ma, Guo, Lei, et al, 2018; Mohanty, Saiers, & Ryan, 2016; Sepehrnia, Fishkis, Huwe, & Bachmann, 2018; VanNess et al, 2019). In ideal porous media and saturated conditions, colloid retention is mainly controlled by the net rate of colloid deposition and release.…”

“…The dynamic nature of nonsteady state flow can cause shifts in chemical factors (e.g., ionic strength, pH, surface charge, and chemical composition of the pore water) and physical factors (e.g., pore size distribution, shrinking, and swelling of the soil) in the unsaturated zone, which might fundamentally influence the importance and magnitude of some of the processes assumed to be primary controls on colloid transport in steady‐state flow systems (Saiers, Hornberger, Gower, & Herman, 2003; Saiers & Lenhart, 2003a, 2003b; Torkzaban, Hassanizadeh, Schijven, Bruijn, & Husman, 2006; Torkzaban, Hassanizadeh, Schijven, & van den Berg, 2006; Wang et al, 2019). Despite the fact that colloid transport in transient flow has received the least attention in colloid research to date (Baumann, 2007; Lazouskaya & Jin, 2008; Lazouskaya, Jin, & Or, 2006; Sang et al, 2013; Wan & Wilson, 1994a), transient flow experiments are often considered suitable for making inferences on the mobilization of colloids, in addition to the transport and retention mechanisms (Cheng & Saiers, 2010; Chequer et al, 2019; Ma et al, 2016; Mohanty et al, 2016; Sepehrnia et al, 2018). This is particularly important for nonpoint source pollution mitigation since transient flow more closely mimics the phenomenon of colloid transport and colloid‐facilitated transport of contaminants as it occurs in real vadose zone environments (Gao et al, 2006; McCarthy & McKay, 2004; Saiers & Lenhart, 2003a; Zhuang et al, 2007).…”

A Modified Time Domain Random Walk Approach for Simulating Colloid Behavior in Fractures: Method Development and Verification

“…These forces are governed by the physical and hydraulic properties of the groundwater‐colloid system and include (i) gravitational force due to the particle weight, (ii) buoyant force combining the effects of fluid density and particle size, and (iii) drag and lift forces resulting from the nonuniform pressure and velocity distributions over the particle. The reader is referred to the studies by Reimus (1995) and Chequer et al (2019) for a detailed description of the electrostatic and hydrodynamic forces and their effects on colloids in groundwater systems.…”