Transport of iron nanoparticles through natural discrete fractures

Cohen, Meirav; Weisbrod, Noam

doi:10.1016/j.watres.2017.11.019

Cited by 21 publications

(44 citation statements)

References 44 publications

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“…This suggests that attachment is the dominant colloid retention mechanism in the water-colloid-fracture systems considered in this work. This finding supports those from several other studies conducted under different water-colloid-fracture system conditions (e.g., Rodrigues and Dickson 2015;Stoll et al 2017;Cohen and Weisbrod 2018).…”

Section: Model Sensitivitysupporting

confidence: 92%

“…The behavior of colloids in fractured groundwater systems has become an increasingly active research area over the past two decades. Advection is the primary mechanism responsible for colloid transport in fractures, while attachment, sedimentation, physical straining, and diffusion into the rock matrix are responsible for retention (Zhang et al 2012;Weisbrod et al 2013;Cohen and Weisbrod 2018). Attachment is a two-step process: the colloid must first contact a fracture wall and subsequently attach (Abdel-salam and Chrysikopoulos 1994).…”

Section: Introductionmentioning

confidence: 99%

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A Genetic Programming–Based Model for Colloid Retention in Fractures

et al. 2019

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Understanding the behavior of colloids in groundwater is critical as some are pathogenic while others may facilitate or inhibit the transport of dissolved contaminants. Colloid behavior in saturated fractured aquifers is governed by the physical and chemical properties of the groundwater‐particle‐fracture system. The interaction between these properties is nonlinear, and there is a need for a mathematical model describing the relationship between them to advance the mechanistic understanding of colloid transport in fractures and facilitate modeling in fractured environments. This paper coupled genetic programming and linear regression within a multigene genetic programming framework to develop a robust mathematical model describing the relationship between colloid retention in fractures and the physical and chemical parameters that describe the system. The data employed for model development and validation were collected from a series of 75 laboratory‐scale colloid tracer experiments conducted under a range of conditions in three laboratory‐induced discrete dolomite fractures and their epoxy replicas. The model sufficiently reproduced the observed data with coefficients of determination (R2) of 0.92 and 0.80 for model development and validation, respectively. A cross‐validation demonstrated the model generality to 86% of the observed data. A variance‐based global sensitivity analysis confirmed that attachment is the primary retention mechanism in the systems employed in this work. The model developed in this study provides a tool describing colloid retention in factures, which furthers the understanding of groundwater‐particle‐fracture system conditions contributing to the retention of colloids and can aid in the design of groundwater remediation strategies and development of groundwater management plans.

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Section: Model Sensitivitysupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

A Genetic Programming–Based Model for Colloid Retention in Fractures

et al. 2019

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“…In previous work, we showed very high potential CIC mobility in fractures and the possibility for CIC transport manipulation (Cohen & Weisbrod, , ). nZVI transport manipulation is beneficial for efficient in situ application; therefore, in this work, the influence of the stabilizer loading and the amount of free stabilizer in the solution, as well as the IS effect on CIC mobility, were further tested and explored.…”

Section: Introductionmentioning

confidence: 75%

“…In previous work, we showed very high potential CIC mobility in fractures and the possibility for CIC transport manipulation (Cohen & Weisbrod, 2018a, 2018b. nZVI transport manipulation is beneficial for efficient 10.1029/2019WR025553…”

Section: Introductionmentioning

confidence: 89%

The Role of Stabilizer Concentration in the Mobility of Carbon‐Supported Nanozerovalent Iron (nZVI) in Fractured Media

Cohen

Yakirevich

Weisbrod

2019

Water Resources Research

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The mobility of nanozerovalent iron (nZVI) particles is of major importance when assessing their effectiveness for use in contaminated sites. Here, the influence of the stabilizer loading on nZVI mobility was investigated in fractured media. nZVI in the form of Carbo‐Iron Colloids (CIC), a composite material of activated carbon as a carrier for nZVI, was used for the tests. CIC was supplemented with carboxymethyl cellulose stabilizer, at three different loadings: 5% wt., 20% wt., and 80% wt., in a moderately saline solution of 250 mM. Transport experiments were conducted in a fractured chalk core, and the characteristics of the solutions and particles were analyzed. The effect of ionic strength was investigated by application of the 80% loading, also in a lower salinity solution of ~3 mM. Transport experiments were modeled, and all results were compared with especially high 1,600% wt. stabilizer loading, from a previous study. Among the different carboxymethyl cellulose loadings, significant differences in mobility and a correlation between mobility and stability were observed. Though, differences in stability were found insignificant. Higher stabilizer concentration and, to a greater extent, a higher number of free stabilizer molecules in solution enhance particle stability and, hence, mobility. A good fit was obtained between the transport experiment results and a model of solute and colloid transport in a single fracture. The model attachment parameters showed a good correlation with the decay rate constants of the stability tests, indicating yet again the significant role played by stability in CIC mobility and the possibility for mobility prediction.

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“…Future research will likely address reactive transport and more complex biogeochemical systems. Further development of the LUC method will include: (1) transport with sorption and biodegradation of organic contaminants (including pesticides, pharmaceuticals, and micropollutants) in macroporous geologic formations (Rosenbom et al 2014;Yu et al 2018); (2) flow and transport in macropores and fractured media under unsaturated conditions (Mortensen et al 2004); (3) transport of inorganic contaminants and colloids (McKay et al 1993;Cohen and Weisbrod 2018;James et al 2018); (4) transport of major cations and anions with electrostatic interactions within the pore water and at the solid/solution interface (Rolle et al 2013b;Muniruzzaman et al 2014); (5) flow and transport of immiscible phases such as chlorinated solvents (Pankow and Cherry 1996;O'Hara et al 2000); (6) impact of chemical and combined physico-chemical heterogeneity (Li et al 2014;Fakhreddine et al 2016;Battistel et al 2018), and (7) microbial metabolism with gas production and determination of efflux gases (Sihota et al 2018). Experimental advances in the LUC setup will also be paralleled by numerical model development.…”

Section: Discussionmentioning

confidence: 99%

A Large Undisturbed Column Method to Study Flow and Transport in Macropores and Fractured Media

Jørgensen¹,

Mosthaf

Rolle

2019

Groundwater

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Intact soil columns can bridge the gap between field studies and idealized laboratory investigations of flow and transport in macropores and fractured media. However, the value of intact column studies is often hampered by shortcomings such as lack of column intactness, small column size, and column rim flow, which can cause serious artifacts and hamper system understanding. The flexible‐wall pressurized large undisturbed column (LUC) method overcomes these limitations and is a valuable approach to analyze fluid flow and solute transport in macroporous and fractured geological formations. The method investigates subsurface processes in complex media, mimicking in situ conditions and facilitating the control of system boundary conditions including effective stress. In recent years, considerable experience has been gained through different applications of the LUC approach. Modeling tools have also been developed for a detailed interpretation of flow and transport processes in LUC systems. This paper describes the steps of the LUC method from column excavation in the field to experimental setup in the laboratory. The description encompasses the key features of the sampling of LUCs in field excavations, the laboratory setup, the procedure for hydraulic and transport experiments, as well as practical challenges and potential issues during operation of an LUC system. Application examples with a fully three‐dimensional numerical model of LUC tracer experiments are also presented to illustrate the quantitative interpretation of transport processes in macroporous clayey tills.

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Transport of iron nanoparticles through natural discrete fractures

Cited by 21 publications

References 44 publications

A Genetic Programming–Based Model for Colloid Retention in Fractures

A Genetic Programming–Based Model for Colloid Retention in Fractures

The Role of Stabilizer Concentration in the Mobility of Carbon‐Supported Nanozerovalent Iron (nZVI) in Fractured Media

A Large Undisturbed Column Method to Study Flow and Transport in Macropores and Fractured Media

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