Coupled solute transport through a polymer-enhanced bentonite
Polymer-enhanced bentonites for geoenvironmental containment barriers, such as bentonite-polyacrylic-acid composite (BPC), generally have low hydraulic conductivity (e.g., k < 10−10 m/s) even when exposed to aggressive waste solutions. However, understanding of diffusion and membrane behavior pro...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2022-12-01
|
| Series: | Soils and Foundations |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0038080622001433 |
| _version_ | 1797996679701463040 |
|---|---|
| author | Shan Tong Kristin M. Sample-Lord |
| author_facet | Shan Tong Kristin M. Sample-Lord |
| author_sort | Shan Tong |
| collection | DOAJ |
| description | Polymer-enhanced bentonites for geoenvironmental containment barriers, such as bentonite-polyacrylic-acid composite (BPC), generally have low hydraulic conductivity (e.g., k < 10−10 m/s) even when exposed to aggressive waste solutions. However, understanding of diffusion and membrane behavior properties of enhanced bentonites and associated impacts on coupled contaminant transport through the barrier remains limited. In this study, hydraulic conductivity (k), effective diffusion coefficients (D*), and membrane efficiencies (ω) were measured for BPC with 3.2 % polymer content (by mass; referred to as BPC-3.2). Tests were performed with potassium chloride (KCl) solutions ranging from dilute (2.5 mM) to aggressive (400 mM) concentrations. As concentration increased, D* increased by a factor of three, ω decreased by two orders of magnitude, and k remained relatively low (1.2 × 10−11 to 2.9 × 10−11 m/s). The experimental results were paired with an existing coupled solute transport model to evaluate the significance of membrane behavior and diffusion on predicted total solute flux through a geosynthetic clay liner (GCL) and a GCL overlying an attenuation layer. The predicted mass flux was diffusion dominated, with the diffusive flux greater than the advective flux by one to two orders of magnitude. Membrane behavior reduced predicted total solute flux through the GCL by 5.8 to 61 %. The results demonstrate the role of coupled solute transport in the long-term performance of bentonite barriers, and advance understanding of contaminant transport in BPC. |
| first_indexed | 2024-04-11T10:20:07Z |
| format | Article |
| id | doaj.art-09ab9e9d9dad425d9d2e86e189857e03 |
| institution | Directory Open Access Journal |
| issn | 2524-1788 |
| language | English |
| last_indexed | 2024-04-11T10:20:07Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Soils and Foundations |
| spelling | doaj.art-09ab9e9d9dad425d9d2e86e189857e032022-12-22T04:29:46ZengElsevierSoils and Foundations2524-17882022-12-01626101235Coupled solute transport through a polymer-enhanced bentoniteShan Tong0Kristin M. Sample-Lord1MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaDepartment of Civil and Environmental Engineering, 800 Lancaster Avenue, Villanova University, Villanova, PA 19085, USA; Corresponding author.Polymer-enhanced bentonites for geoenvironmental containment barriers, such as bentonite-polyacrylic-acid composite (BPC), generally have low hydraulic conductivity (e.g., k < 10−10 m/s) even when exposed to aggressive waste solutions. However, understanding of diffusion and membrane behavior properties of enhanced bentonites and associated impacts on coupled contaminant transport through the barrier remains limited. In this study, hydraulic conductivity (k), effective diffusion coefficients (D*), and membrane efficiencies (ω) were measured for BPC with 3.2 % polymer content (by mass; referred to as BPC-3.2). Tests were performed with potassium chloride (KCl) solutions ranging from dilute (2.5 mM) to aggressive (400 mM) concentrations. As concentration increased, D* increased by a factor of three, ω decreased by two orders of magnitude, and k remained relatively low (1.2 × 10−11 to 2.9 × 10−11 m/s). The experimental results were paired with an existing coupled solute transport model to evaluate the significance of membrane behavior and diffusion on predicted total solute flux through a geosynthetic clay liner (GCL) and a GCL overlying an attenuation layer. The predicted mass flux was diffusion dominated, with the diffusive flux greater than the advective flux by one to two orders of magnitude. Membrane behavior reduced predicted total solute flux through the GCL by 5.8 to 61 %. The results demonstrate the role of coupled solute transport in the long-term performance of bentonite barriers, and advance understanding of contaminant transport in BPC.http://www.sciencedirect.com/science/article/pii/S0038080622001433Bentonite polymer compositeCoupled solute transportGeosynthetic clay linerDiffusionMembrane behavior |
| spellingShingle | Shan Tong Kristin M. Sample-Lord Coupled solute transport through a polymer-enhanced bentonite Soils and Foundations Bentonite polymer composite Coupled solute transport Geosynthetic clay liner Diffusion Membrane behavior |
| title | Coupled solute transport through a polymer-enhanced bentonite |
| title_full | Coupled solute transport through a polymer-enhanced bentonite |
| title_fullStr | Coupled solute transport through a polymer-enhanced bentonite |
| title_full_unstemmed | Coupled solute transport through a polymer-enhanced bentonite |
| title_short | Coupled solute transport through a polymer-enhanced bentonite |
| title_sort | coupled solute transport through a polymer enhanced bentonite |
| topic | Bentonite polymer composite Coupled solute transport Geosynthetic clay liner Diffusion Membrane behavior |
| url | http://www.sciencedirect.com/science/article/pii/S0038080622001433 |
| work_keys_str_mv | AT shantong coupledsolutetransportthroughapolymerenhancedbentonite AT kristinmsamplelord coupledsolutetransportthroughapolymerenhancedbentonite |