Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation
Studying contaminant transport in the capillary fringe (CF), a crucial part of the vadose zone, offers insights into the mechanisms controlling pollution in soils and groundwater aquifers. This paper investigated contaminant transport in the CF by continuously injecting a conservative tracer (NaCl)...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2024-09-01
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| Series: | Emerging Contaminants |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S240566502400009X |
| _version_ | 1797304622929412096 |
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| author | Taotao Lu Feiyu Chen Xiaochen Liu Xue Bai Hao Peng Shuangcheng Tang |
| author_facet | Taotao Lu Feiyu Chen Xiaochen Liu Xue Bai Hao Peng Shuangcheng Tang |
| author_sort | Taotao Lu |
| collection | DOAJ |
| description | Studying contaminant transport in the capillary fringe (CF), a crucial part of the vadose zone, offers insights into the mechanisms controlling pollution in soils and groundwater aquifers. This paper investigated contaminant transport in the CF by continuously injecting a conservative tracer (NaCl) and graphene oxide nanoparticle (GONP), an adsorptive contaminant, into a sandbox. After entering the CF from the unsaturated zone, both NaCl and GONP underwent lateral transport. The breakthrough curves (BTCs) for NaCl and GONP were derived from water samples collected at predetermined sampling holes. Subsequently, contaminant transport in the CF was modeled using a one-dimensional–two-dimensional (1D-2D) coupled hydrodynamic model. This model incorporated lateral dispersivity (αL = 1.198 cm) and longitudinal dispersivity (αT = 0.286 cm), calculated using a point-by-point method. The hydrodynamic dispersion coefficients obtained were then applied to the Brooks and Corey (BC) and the van Genuchten (VG) parametric models. The BC model more accurately simulated the NaCl migration compared to the VG model, leading to its application in simulating GONP transport in the CF. However, the simulated BTCs for GONP showed a lag behind the measured data, especially at high ionic strengths. This discrepancy was attributed to the variable adsorption partition coefficient of GONP under different ionic conditions. During the experiment, GONP adsorption onto the porous media's surface altered the capillary dynamics, notably increasing capillary rise height, decreasing seepage velocity, and reducing GONP dispersion. Therefore, it is necessary to consider the adsorption capacity of the contaminants in order to accurately assess their transport within the vadose zone. |
| first_indexed | 2024-03-08T00:12:09Z |
| format | Article |
| id | doaj.art-6e55626bbe5440bea262d0a791179865 |
| institution | Directory Open Access Journal |
| issn | 2405-6650 |
| language | English |
| last_indexed | 2024-03-08T00:12:09Z |
| publishDate | 2024-09-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Emerging Contaminants |
| spelling | doaj.art-6e55626bbe5440bea262d0a7911798652024-02-17T06:38:00ZengKeAi Communications Co., Ltd.Emerging Contaminants2405-66502024-09-01103100308Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulationTaotao Lu0Feiyu Chen1Xiaochen Liu2Xue Bai3Hao Peng4Shuangcheng Tang5College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, 225009, ChinaCollege of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, 225009, ChinaHydrogeology and Engineering Geology Institute of Hubei Geological Bureau, Jinzhou, 434020, ChinaCollege of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, 225009, ChinaCollege of Environment and Civil Engineering, Chengdu University of Technology, Chengdu, 610059, China; Corresponding author.College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou, 225009, China; Corresponding author.Studying contaminant transport in the capillary fringe (CF), a crucial part of the vadose zone, offers insights into the mechanisms controlling pollution in soils and groundwater aquifers. This paper investigated contaminant transport in the CF by continuously injecting a conservative tracer (NaCl) and graphene oxide nanoparticle (GONP), an adsorptive contaminant, into a sandbox. After entering the CF from the unsaturated zone, both NaCl and GONP underwent lateral transport. The breakthrough curves (BTCs) for NaCl and GONP were derived from water samples collected at predetermined sampling holes. Subsequently, contaminant transport in the CF was modeled using a one-dimensional–two-dimensional (1D-2D) coupled hydrodynamic model. This model incorporated lateral dispersivity (αL = 1.198 cm) and longitudinal dispersivity (αT = 0.286 cm), calculated using a point-by-point method. The hydrodynamic dispersion coefficients obtained were then applied to the Brooks and Corey (BC) and the van Genuchten (VG) parametric models. The BC model more accurately simulated the NaCl migration compared to the VG model, leading to its application in simulating GONP transport in the CF. However, the simulated BTCs for GONP showed a lag behind the measured data, especially at high ionic strengths. This discrepancy was attributed to the variable adsorption partition coefficient of GONP under different ionic conditions. During the experiment, GONP adsorption onto the porous media's surface altered the capillary dynamics, notably increasing capillary rise height, decreasing seepage velocity, and reducing GONP dispersion. Therefore, it is necessary to consider the adsorption capacity of the contaminants in order to accurately assess their transport within the vadose zone.http://www.sciencedirect.com/science/article/pii/S240566502400009XCapillary fringeTransportSandbox experimentNumerical simulation |
| spellingShingle | Taotao Lu Feiyu Chen Xiaochen Liu Xue Bai Hao Peng Shuangcheng Tang Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation Emerging Contaminants Capillary fringe Transport Sandbox experiment Numerical simulation |
| title | Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation |
| title_full | Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation |
| title_fullStr | Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation |
| title_full_unstemmed | Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation |
| title_short | Transport of graphene oxide in the capillary fringe: Insights from sandbox experiments and numerical simulation |
| title_sort | transport of graphene oxide in the capillary fringe insights from sandbox experiments and numerical simulation |
| topic | Capillary fringe Transport Sandbox experiment Numerical simulation |
| url | http://www.sciencedirect.com/science/article/pii/S240566502400009X |
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