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Scandelli H, Ahmadi-Senichault A, Levet C, Lachaud J. Computation of the Permeability Tensor of Non-Periodic Anisotropic Porous Media from 3D Images. Transp Porous Media 2022. [DOI: 10.1007/s11242-022-01766-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Stockmann M, Fritsch K, Bok F, Fernandes MM, Baeyens B, Steudtner R, Müller K, Nebelung C, Brendler V, Stumpf T, Schmeide K. New insights into U(VI) sorption onto montmorillonite from batch sorption and spectroscopic studies at increased ionic strength. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150653. [PMID: 34597569 DOI: 10.1016/j.scitotenv.2021.150653] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/06/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
The influence of ionic strength up to 3 mol kg-1 (background electrolytes NaCl or CaCl2) on U(VI) sorption onto montmorillonite was investigated as function of pHc in absence and presence of CO2. A multi-method approach combined batch sorption experiments with spectroscopic methods (time-resolved laser-induced fluorescence spectroscopy (TRLFS) and in situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR)). In the absence of atmospheric carbonate, U(VI) sorption was nearly 99% above pHc 6 in both NaCl and CaCl2 and no significant effect of ionic strength was found. At lower pH, cation exchange was strongly reduced with increasing ionic strength. In the presence of carbonate, U(VI) sorption was reduced above pHc 7.5 in NaCl and pHc 6 in CaCl2 system due to formation of aqueous UO2(CO3)x(2-2x) and Ca2UO2(CO3)3 complexes, respectively, as verified by TRLFS. A significant ionic strength effect was observed due to the formation of Ca2UO2(CO3)3(aq), which strongly decreases U(VI) sorption with increasing ionic strength. The joint analysis of determined sorption data together with literature data (giving a total of 213 experimental data points) allowed to derive a consistent set of surface complexation reactions and constants based on the 2SPNE SC/CE approach, yielding log K°≡SSOUO2+ = 2.42 ± 0.04, log K°≡SSOUO2OH = -4.49 ± 0.7, and log K°≡SSOUO2(OH)32- = -20.5 ± 0.4. Ternary uranyl carbonate surface complexes were not required to describe the data. With this reduced set of surface complexes, an improved robust sorption model was obtained covering a broad variety of geochemical settings over wide ranges of ionic strengths and groundwater compositions, which subsequently was validated by an independent original dataset. This model improves the understanding of U(VI) retention by clay minerals and enables now predictive modeling of U(VI) sorption processes in complex clay rich natural environments.
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Affiliation(s)
- M Stockmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany.
| | - K Fritsch
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - F Bok
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - M Marques Fernandes
- Paul Scherrer Institute, Laboratory for Waste Management, 5232 Villigen PSI, Switzerland
| | - B Baeyens
- Paul Scherrer Institute, Laboratory for Waste Management, 5232 Villigen PSI, Switzerland
| | - R Steudtner
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - K Müller
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - C Nebelung
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - V Brendler
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - T Stumpf
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany
| | - K Schmeide
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstr. 400, 01328 Dresden, Germany.
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Evolution of Hydraulic Conductivity of Unsaturated Compacted Na-Bentonite under Confined Condition-Including the Microstructure Effects. MATERIALS 2021; 15:ma15010219. [PMID: 35009364 PMCID: PMC8745896 DOI: 10.3390/ma15010219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 11/30/2022]
Abstract
Compacted bentonite is envisaged as engineering buffer/backfill material in geological disposal for high-level radioactive waste. In particular, Na-bentonite is characterised by lower hydraulic conductivity and higher swelling competence and cation exchange capacity, compared with other clays. A solid understanding of the hydraulic behaviour of compacted bentonite remains challenging because of the microstructure expansion of the pore system over the confined wetting path. This work proposed a novel theoretical method of pore system evolution of compacted bentonite based on its stacked microstructure, including the dynamic transfer from micro to macro porosity. Furthermore, the Kozeny–Carman equation was revised to evaluate the saturated hydraulic conductivity of compacted bentonite, taking into account microstructure effects on key hydraulic parameters such as porosity, specific surface area and tortuosity. The results show that the prediction of the revised Kozeny–Carman model falls within the acceptable range of experimental saturated hydraulic conductivity. A new constitutive relationship of relative hydraulic conductivity was also developed by considering both the pore network evolution and suction. The proposed constitutive relationship well reveals that unsaturated hydraulic conductivity undergoes a decrease controlled by microstructure evolution before an increase dominated by dropping gradient of suction during the wetting path, leading to a U-shaped relationship. The predictive outcomes of the new constitutive relationship show an excellent match with laboratory observation of unsaturated hydraulic conductivity for GMZ and MX80 bentonite over the entire wetting path, while the traditional approach overestimates the hydraulic conductivity without consideration of the microstructure effect.
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Sadeghi MA, Agnaou M, Barralet J, Gostick J. Dispersion modeling in pore networks: A comparison of common pore-scale models and alternative approaches. JOURNAL OF CONTAMINANT HYDROLOGY 2020; 228:103578. [PMID: 31767229 DOI: 10.1016/j.jconhyd.2019.103578] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/25/2019] [Accepted: 11/08/2019] [Indexed: 06/10/2023]
Abstract
Mass transfer in porous media resulting from dispersion occurs in a wide variety of applications such as water treatment, flow batteries, flow in aquifers, enhanced oil recovery, and packed-bed reactors. The underlying mechanisms of dispersion are the molecular diffusion superimposed on the advective transport induced by the fluid flow. Modeling dispersion in pore networks can be performed at a much lower computational cost compared to that in direct numerical simulations (DNS) such as finite element or the lattice Boltzmann methods, so it can be regarded as a suitable alternative provided its accuracy is sufficient. The most common approach to model dispersion in network models is based on the first-order upwind scheme, despite its known limitations in terms of accuracy for certain flow and transport regimes. In this study, three alternative pore-scale models for dispersion, which are more accurate than the existing ones, were derived and tested in pore network simulations. These models were adopted from the CFD literature and are based on a spatial discretization of the advection-diffusion equation using the hybrid and power-law finite difference schemes and the exact solution of the one-dimensional advection-diffusion equation. Finally, considering dispersion problems over arbitrary porous structures, consisting of stick-and-ball geometries, and different flow and mass transfer arrangements, the developed models were validated. Validation was carried-out through comparisons between results obtained with DNS, using a finite element solver, and those from pore network simulations. It is shown that under a wide range of dispersion regimes (up to the onset of the dispersion power-law regime), the relative error (with respect to DNS results) introduced by the power-law and exact solution-based models is consistently below 1%, whereas the use of the upwind scheme leads to >10% of relative error, depending on the dispersion regime. All the dispersion models developed in this study were implemented as part of the open-source network modeling package, OpenPNM.
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Affiliation(s)
| | - Mehrez Agnaou
- Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada
| | - Jake Barralet
- Department of Dentistry, McGill University, Montreal, QC, Canada; Department of Surgery, Faculty of Medicine, McGill University, Montreal, QC, Canada
| | - Jeff Gostick
- Department of Chemical Engineering, McGill University, Montreal, QC, Canada; Department of Chemical Engineering, University of Waterloo, Waterloo, ON, Canada.
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Gerke KM, Karsanina MV, Katsman R. Calculation of tensorial flow properties on pore level: Exploring the influence of boundary conditions on the permeability of three-dimensional stochastic reconstructions. Phys Rev E 2019; 100:053312. [PMID: 31869888 DOI: 10.1103/physreve.100.053312] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Indexed: 06/10/2023]
Abstract
While it is well known that permeability is a tensorial property, it is usually reported as a scalar property or only diagonal values are reported. However, experimental evaluation of tensorial flow properties is problematic. Pore-scale modeling using three-dimensional (3D) images of porous media with subsequent upscaling to a continuum scale (homogenization) is a valuable alternative. In this study, we explore the influence of different types of boundary conditions on the external walls of the representative modeling domain along the applied pressure gradient on the magnitude and orientation of the computed permeability tensor. To implement periodic flow boundary conditions, we utilized stochastic reconstruction methodology to create statistically similar (to real porous media structures) geometrically periodic 3D structures. Stochastic reconstructions are similar to encapsulation of the porous media into statistically similar geometrically periodic one with the same permeability tensor. Seven main boundary conditions (BC) were implemented: closed walls, periodic flow, slip on the walls, linear pressure, translation, symmetry, and immersion. The different combinations of BCs amounted to a total number of 15 BC variations. All these BCs significantly influenced the resulting tensorial permeabilities, including both magnitude and orientation. Periodic boundary conditions produced the most physical flow patterns, while other classical BCs either suppressed crucial transversal flows or resulted in unphysical currents. Our results are crucial to performing flow properties upscaling and will be relevant to computing not only single-phase but also multiphase flow properties. Moreover, other calculation of physical properties such as some mechanical, transport, or heat conduction properties may benefit from the technique described in this study.
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Affiliation(s)
- Kirill M Gerke
- Schmidt Institute of Physics of the Earth of Russian Academy of Sciences, Moscow 107031, Russia
- Institute of Geospheres Dynamics of Russian Academy of Sciences, Moscow 119334, Russia
- Dokuchaev Soil Science Institute of Russian Academy of Sciences, Moscow 119017, Russia
- Kazan Federal University, Kazan 420008, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Marina V Karsanina
- Schmidt Institute of Physics of the Earth of Russian Academy of Sciences, Moscow 107031, Russia
- Institute of Geospheres Dynamics of Russian Academy of Sciences, Moscow 119334, Russia
| | - Regina Katsman
- Department of Marine Geosciences, Haifa University, Haifa 3498838, Israel
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Liu DX, Zuo R, Jivkov AP, Wang JS, Hu LT, Huang LX. Effect of colloids on non-Fickian transport of strontium in sediments elucidated by continuous-time random walk analysis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 252:1491-1499. [PMID: 31265960 DOI: 10.1016/j.envpol.2019.06.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/14/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
Understanding the influence of colloids on radionuclide migration is of significance to evaluate environmental risks for radioactive waste disposals. In order to formulate an appropriate modelling framework that can quantify and interpret the anomalous transport of Strontium (Sr) in the absence and presence of colloids, the continuous time random walk (CTRW) approach is implemented in this work using available experimental information. The results show that the transport of Sr and its recovery are enhanced in the presence of colloids. The causes can be largely attributed to the trap-release processes, e.g. electrostatic interactions of Sr, colloids and natural sediments, and differences in pore structures, which gave rise to the varying interstitial velocities of dissolved and, if any, colloid-associated Sr. Good agreement between the CTRW simulations and the column-scale observations is demonstrated. Regardless of the presence of colloids, the CTRW modelling captures the characteristics of non-Fickian anomalous transport (0 < β < 2) of Sr. In particular, a range of 0 < β < 1, corresponding to the cases with greater recoveries, reveal strongly non-Fickian transport with distinctive earlier arrivals and tailing effects, likely due to the physicochemical heterogeneities, i.e. the repulsive interactions and/or the macro-pores originating from local heterogeneities. The results imply that colloids can increase the Sr transport as a barrier of Sr sorption onto sediments herein, apart from often being carriers of sored radionuclides in aqueous phase. From a modelling perspective, the findings show that the established CTRW model is valid for quantifying the non-Fickian and promoted transport of Sr with colloids.
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Affiliation(s)
- Dong-Xu Liu
- College of Water Sciences, Beijing Normal University, Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, PR China; Northwest Institute of Nuclear Technology, Xi'an 710024, PR China
| | - Rui Zuo
- College of Water Sciences, Beijing Normal University, Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, PR China.
| | - Andrey P Jivkov
- Research Centre for Radwaste & Decommissioning and Modelling & Simulation Centre, Dalton Nuclear Institute, The University of Manchester, Manchester M13 9PL, UK
| | - Jin-Sheng Wang
- College of Water Sciences, Beijing Normal University, Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, PR China
| | - Li-Tang Hu
- College of Water Sciences, Beijing Normal University, Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education of China, Beijing 100875, PR China
| | - Liu-Xing Huang
- Northwest Institute of Nuclear Technology, Xi'an 710024, PR China
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Langlois V, Trinh VH, Lusso C, Perrot C, Chateau X, Khidas Y, Pitois O. Permeability of solid foam: Effect of pore connections. Phys Rev E 2018; 97:053111. [PMID: 29906824 DOI: 10.1103/physreve.97.053111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Indexed: 06/08/2023]
Abstract
In this paper, we study how the permeability of solid foam is modified by the presence of membranes that close partially or totally the cell windows connecting neighboring pores. The finite element method (FEM) simulations computing the Stokes problem are performed at both pore and macroscopic scales. For foam with fully interconnected pores, we obtain a robust power-law relationship between permeability and aperture size. This result is due to the local pressure drop mechanism through the aperture as described by Sampson for fluid flow through a circular orifice in a thin plate. Based on this local law, pore-network simulation of simple flow is used and is shown to reproduce FEM results. Then this low computational cost method is used to study in detail the effect of an open window fraction on the percolation properties of the foam pore space. The results clarify the effect of membranes on foam permeability. Finally, Kirkpatrick's model is adapted to provide analytical expressions that allow for our simulation results to be successfully reproduced.
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Affiliation(s)
- V Langlois
- Université Paris-Est, Laboratoire Géomatériaux et Environnement (EA 4508), UPEM, F-77454, Marne-la-Vallée, France
| | - V H Trinh
- Université Paris-Est, Laboratoire Modélisation et Simulation Multi Échelle, MSME UMR 8208 CNRS, Marne-la-Vallée 77454, France
| | - C Lusso
- Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, École des Ponts ParisTech, IFSTTAR Marne-la-Vallée, France
| | - C Perrot
- Université Paris-Est, Laboratoire Modélisation et Simulation Multi Échelle, MSME UMR 8208 CNRS, Marne-la-Vallée 77454, France
| | - X Chateau
- Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, École des Ponts ParisTech, IFSTTAR Marne-la-Vallée, France
| | - Y Khidas
- Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, École des Ponts ParisTech, IFSTTAR, 5 Bd Descartes, 77454 Marne-la-Vallée, France
| | - O Pitois
- Université Paris-Est, Laboratoire Navier, UMR 8205 CNRS, École des Ponts ParisTech, IFSTTAR cité Descartes, 2 allée Kepler, 77420 Champs-sur-Marne, France
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Moradi F, Ganji MD, Sarrafi Y. Tunable phenol remediation from wastewater using SWCNT-based, sub-nanometer porous membranes: reactive molecular dynamics simulations and DFT calculations. Phys Chem Chem Phys 2017; 19:8388-8399. [DOI: 10.1039/c6cp08525c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactive molecular dynamic (MD) simulations and first-principle density functional theory (DFT) calculations were used to investigate the performance of SWCNT-based, sub-nanometer porous membranes for phenol remediation from wastewater.
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Affiliation(s)
- F. Moradi
- Department of Organic Chemistry
- Faculty of Chemistry
- University of Mazandaran
- Babolsar
- Iran
| | - M. Darvish Ganji
- Department of Nanochemistry
- Faculty of Pharmaceutical Chemistry
- Pharmaceutical Sciences Branch
- Islamic Azad University (IAUPS)
- Tehran
| | - Y. Sarrafi
- Department of Organic Chemistry
- Faculty of Chemistry
- University of Mazandaran
- Babolsar
- Iran
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Xiong Q, Baychev TG, Jivkov AP. Review of pore network modelling of porous media: Experimental characterisations, network constructions and applications to reactive transport. JOURNAL OF CONTAMINANT HYDROLOGY 2016; 192:101-117. [PMID: 27442725 DOI: 10.1016/j.jconhyd.2016.07.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 06/23/2016] [Accepted: 07/09/2016] [Indexed: 06/06/2023]
Abstract
Pore network models have been applied widely for simulating a variety of different physical and chemical processes, including phase exchange, non-Newtonian displacement, non-Darcy flow, reactive transport and thermodynamically consistent oil layers. The realism of such modelling, i.e. the credibility of their predictions, depends to a large extent on the quality of the correspondence between the pore space of a given medium and the pore network constructed as its representation. The main experimental techniques for pore space characterisation, including direct imaging, mercury intrusion porosimetry and gas adsorption, are firstly summarised. A review of the main pore network construction techniques is then presented. Particular focus is given on how such constructions are adapted to the data from experimentally characterised pore systems. Current applications of pore network models are considered, with special emphasis on the effects of adsorption, dissolution and precipitation, as well as biomass growth, on transport coefficients. Pore network models are found to be a valuable tool for understanding and predicting meso-scale phenomena, linking single pore processes, where other techniques are more accurate, and the homogenised continuum porous media, used by engineering community.
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Affiliation(s)
- Qingrong Xiong
- Modelling & Simulation Centre and Research Centre for Radwaste & Decommissioning, School of Mechanical Aerospace & Civil Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - Todor G Baychev
- Modelling & Simulation Centre and Research Centre for Radwaste & Decommissioning, School of Mechanical Aerospace & Civil Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Andrey P Jivkov
- Modelling & Simulation Centre and Research Centre for Radwaste & Decommissioning, School of Mechanical Aerospace & Civil Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
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