Transport of colloidal particles in microscopic porous medium analogs with surface charge heterogeneity: experiments and fundamental role of single-bead deposition

Journal Article · Tue Nov 03 04:00:00 EST 2020 · Environment Science and Technology

DOI:https://doi.org/10.1021/acs.est.0c03225· OSTI ID:1713320

Guo, Yang ^[1]; Lou, Jincheng ^[1]; Cho, Jae Kyoung ^[1]; Tilton, Nils ^[1]; Chun, Jaehun ^[2]; Um, Wooyong ^[3]; Yin, Xiaolong ^[1]; Neeves, Keith B. ^[4]; Wu, Ning ^[5]

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1. Colorado School Of Mines
2. BATTELLE (PACIFIC NW LAB)
3. VISITORS
4. University of Colorado at Denver
5. Colorado School of Mines

Understanding colloid transport in subsurface environments is challenging due to complex interactions between colloids, ground water, and porous media over several length scales. Here, we study the transport of colloidal particles through bead-assembled microfluidic porous media analogs (PMAs) with surface charge heterogeneity. The pore-scale dynamics of colloidal particle deposition were measured, as well as the breakthrough curves (BTC) and retention profiles (RP) of deposited colloidal particles at the scale of the entire PMA. From pore-scale experiments, the maximum surface coverage (?max = 0.51) was measured directly, from which the surface blocking function and deposition coefficient (kpore = 3.56 s-1) were obtained. Using these pore-scale parameters, the transport of colloidal particles was modeled using a one-dimensional advection-dispersion equation under the assumption of irreversible adsorption between oppositely charged beads and colloids, showing good agreement with experimental data. This work presents a new approach to fabricate chemically heterogeneous porous media in a microfluidic device that enables direct measurements of pore-scale colloidal deposition. The approach allows a quantitative prediction of colloidal breakthrough and retention via coupling of direct measurements and an advection-dispersion-deposition model.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1713320
• Report Number(s): PNNL-SA-152926
• Journal Information: Environment Science and Technology, Journal Name: Environment Science and Technology Journal Issue: 21 Vol. 54
• Country of Publication: United States
• Language: English