Coupled effect of flow velocity and structural heterogeneity on transport and release of kaolinite colloids in saturated
- PDF / 1,368,157 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 96 Downloads / 143 Views
RESEARCH ARTICLE
Coupled effect of flow velocity and structural heterogeneity on transport and release of kaolinite colloids in saturated porous media Meng Mao 1 & Xiaoli Zheng 1 & Chong Chen 1 & Kang Zhao 1 & Chaorui Yan 1 & Prabhakar Sharma 2 & Jianying Shang 1 Received: 30 December 2019 / Accepted: 18 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Understanding the behavior and fate of clay colloids in water-saturated porous media is critical to assess its environmental impact and potential risk since clay is commonly a carrier of many contaminants. Column experiments with four-packing configurations were designed to understand the coupled effects of column structural heterogeneity and the flow velocity on the transport and fate of kaolinite colloids in the saturated porous media. The results showed that the structural heterogeneity could have facilitated the transport of kaolinite colloids in saturated porous media. For the columns with strong heterogeneity, the preferential flow paths led to an early breakthrough of kaolinite. Only few kaolinite colloids were released with slow flow rate; however, the released peak concentration and release percentage of kaolinite colloids had further increased with the high flow velocity. In the layered column, there was significant kaolinite’s retention at the interface where water passed from fine to coarse quartz sand. All results indicated that both flow rates and media characteristics played an important role in controlling kaolinite’s fate and transport in porous media. A thorough understanding of these processes had an important significance for pollution control in subsurface natural environment where heterogeneous soil and variation in flow pattern are usually common. Keywords Kaolinite . Transport . Retention . Release . Structural heterogeneity . Quartz sand
Introduction Kaolinite [Al2Si2O5(OH)4] is one of the most common clay minerals in the subsurface (Gu and Evans 2008; Zhu et al. 2012; Chrysikopoulos et al. 2017). It is the second most abun-
Responsible Editor: Philippe Garrigues Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-020-09806-w) contains supplementary material, which is available to authorized users. * Prabhakar Sharma [email protected] * Jianying Shang [email protected] 1
College of Land Science and Technology, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, China Agricultural University, Beijing 100193, China
2
School of Ecology and Environment Studies, Nalanda University, Nalanda, Rajgir, Bihar, India
dant clay mineral in ocean sediments and is common in soils of tropical region (Grim 1968). Kaolinite has been used in medicine, ceramic, and other industries (Li et al. 2012; Awad et al. 2017). Kaolinite possesses permanent negative charges (Akbour et al. 2002; Gu and Evans 2008) and colloidal kaolinite in soils is mobile (Zhu et al. 2012). When the pollutants are adsorbed onto the colloids, mobile colloids in su
Data Loading...
