Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media
In this study, four homogeneous porous media (HPM1-HPM4), consisting of distinct proportions of sand-sized and clay-sized solid beads, were prepared and used as single fracture infills. Flow and nonreactive solute transport experiments in HPM1-HPM4 under three flow rates were conducted, and the meas...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2021/1207971 |
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| author | Albert Kwame Kwaw Zhi Dou Jinguo Wang Yuting Zhang Xueyi Zhang Wenyuan Zhu Portia Annabelle Opoku |
| author_facet | Albert Kwame Kwaw Zhi Dou Jinguo Wang Yuting Zhang Xueyi Zhang Wenyuan Zhu Portia Annabelle Opoku |
| author_sort | Albert Kwame Kwaw |
| collection | DOAJ |
| description | In this study, four homogeneous porous media (HPM1-HPM4), consisting of distinct proportions of sand-sized and clay-sized solid beads, were prepared and used as single fracture infills. Flow and nonreactive solute transport experiments in HPM1-HPM4 under three flow rates were conducted, and the measured breakthrough curves (BTCs) were quantified using conventional advection-dispersion equation (ADE), mobile-immobile model (MIM), and continuous time random walk (CTRW) model with truncated power law transition time distribution. The measured BTCs showed stronger non-Fickian behaviour in HPM2-HPM4 (which had clay) than in HPM1 (which had no clay), implying that clay enhanced the non-Fickian transport. As the fraction of clay increased, the global error of ADE fits also increased, affirming the inefficiency of ADE in capturing the clay-induced non-Fickian behaviour. MIM and CTRW performed better in capturing the non-Fickian behaviour. Nonetheless, CTRW’s performance was robust. 12.5% and 25% of clay in HPM2 and HPM3, respectively, decreased the flowing fluid region and increased the solute exchange rate between the flowing and stagnant fluid regions in MIM. For CTRW, the power law exponent (βCTRW) values were 1.96, 1.75, and 1.63 in HPM1-HPM3, respectively, implying enhanced non-Fickian behaviour. However, for HPM4, whose clay fraction was 50%, the βCTRW value was 1.87, implying a deviation in the trend of non-Fickian enhancement with increasing clay fraction. This deviation indicated that non-Fickian behaviour enhancement depended on the fraction of clay present. Moreover, increasing flow rate enhanced the non-Fickian transport based on βCTRW. |
| format | Article |
| id | doaj-art-e5c6705f30dc40d08ef77ab04e443635 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-e5c6705f30dc40d08ef77ab04e4436352025-08-20T03:26:20ZengWileyGeofluids1468-81151468-81232021-01-01202110.1155/2021/12079711207971Influence of Clay on Solute Transport in Saturated Homogeneous Mixed MediaAlbert Kwame Kwaw0Zhi Dou1Jinguo Wang2Yuting Zhang3Xueyi Zhang4Wenyuan Zhu5Portia Annabelle Opoku6School of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaSchool of Earth Science and Engineering, Hohai University, Nanjing 210098, ChinaState Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, ChinaIn this study, four homogeneous porous media (HPM1-HPM4), consisting of distinct proportions of sand-sized and clay-sized solid beads, were prepared and used as single fracture infills. Flow and nonreactive solute transport experiments in HPM1-HPM4 under three flow rates were conducted, and the measured breakthrough curves (BTCs) were quantified using conventional advection-dispersion equation (ADE), mobile-immobile model (MIM), and continuous time random walk (CTRW) model with truncated power law transition time distribution. The measured BTCs showed stronger non-Fickian behaviour in HPM2-HPM4 (which had clay) than in HPM1 (which had no clay), implying that clay enhanced the non-Fickian transport. As the fraction of clay increased, the global error of ADE fits also increased, affirming the inefficiency of ADE in capturing the clay-induced non-Fickian behaviour. MIM and CTRW performed better in capturing the non-Fickian behaviour. Nonetheless, CTRW’s performance was robust. 12.5% and 25% of clay in HPM2 and HPM3, respectively, decreased the flowing fluid region and increased the solute exchange rate between the flowing and stagnant fluid regions in MIM. For CTRW, the power law exponent (βCTRW) values were 1.96, 1.75, and 1.63 in HPM1-HPM3, respectively, implying enhanced non-Fickian behaviour. However, for HPM4, whose clay fraction was 50%, the βCTRW value was 1.87, implying a deviation in the trend of non-Fickian enhancement with increasing clay fraction. This deviation indicated that non-Fickian behaviour enhancement depended on the fraction of clay present. Moreover, increasing flow rate enhanced the non-Fickian transport based on βCTRW.http://dx.doi.org/10.1155/2021/1207971 |
| spellingShingle | Albert Kwame Kwaw Zhi Dou Jinguo Wang Yuting Zhang Xueyi Zhang Wenyuan Zhu Portia Annabelle Opoku Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media Geofluids |
| title | Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media |
| title_full | Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media |
| title_fullStr | Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media |
| title_full_unstemmed | Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media |
| title_short | Influence of Clay on Solute Transport in Saturated Homogeneous Mixed Media |
| title_sort | influence of clay on solute transport in saturated homogeneous mixed media |
| url | http://dx.doi.org/10.1155/2021/1207971 |
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