25 results on '"Morales, Verónica L."'
Search Results
2. Relating mechanistic fate with spatial positioning for colloid transport in surface heterogeneous porous media.
- Author
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Patiño, Janis E, Johnson, William P, and Morales, Verónica L
- Subjects
Anomalous transport ,Surface chemical heterogeneity ,X-ray micro-computed tomography ,interfaces ,X-ray micro -computed tomography ,Physical Sciences ,Chemical Sciences ,Engineering ,Chemical Physics - Abstract
HypothesesThe transport behavior of colloids in subsurface porous media is altered by surface chemical and physical heterogeneities. Understanding the mechanisms involved and distribution outcomes is crucial to assess and control groundwater contamination. The multi-scale processes that broaden residence time distribution for particles in the medium are here succinctly described with an upscaling model. Experiments/model: The spatial distribution of silver particles along glass bead-packed columns obtained from X-ray micro-computed tomography and a mechanistic upscaling model were used to study colloid retention across interface-, collector-, pore-, and Darcy-scales. Simulated energy profiles considering variable colloid-grain interactions were used to determine collector efficiencies from particle trajectories via full force-torque balance. Rate coefficients were determined from collector efficiencies to parameterize the advective-dispersive-reactive model that reports breakthrough curves and depth profiles.FindingsOur results indicate that: (i) with surface heterogeneity, individual colloid-grain interactions are non-unique and span from repulsive to attractive extremes; (ii) experimentally observed spatial positioning of retention at grain-water interfaces and grain-to-grain contacts is governed respectively by mechanistic attachment to the grain surface and retention without contact at rear-flow stagnation zones, and (iii) experimentally observed non-monotonic retention profiles and heavy-tailed breakthrough curves can be modeled with explicit implementation of heterogeneity at smaller scales.
- Published
- 2023
3. Retention Site Contribution Toward Silver Particle Immobilization in Porous Media
- Author
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Patiño, Janis E, Pérez‐Reche, Francisco J, and Morales, Verónica L
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colloid ,filtration ,interfaces ,pore structure ,upscaling ,stagnation zones ,Physical Geography and Environmental Geoscience ,Civil Engineering ,Environmental Engineering - Abstract
This work investigates the role that pore structure plays in colloid retention across scales with a novel methodology based on image analysis. Experiments were designed to quantify–with robust statistics–the contribution from commonly proposed retention sites toward colloid immobilization. Specific retention sites include solid-water interface, air-water interface, air-water-solid triple point, grain-to-grain contacts, and thin films. Variable conditions for pore-water content, velocity, and chemistry were tested in a model glass bead porous medium with silver microspheres. Concentration signals from effluent breakthrough and spatial profiles of retained particles from micro X-ray Computed Tomography were used to compute mass balances and enumerate pore-scale regions of interest in three dimensions. At the Darcy-scale, retained colloids follow non-monotonic deposition profiles, which implicates effects from flow-stagnation zones. The spatial distribution of immobilized colloids along the porous medium depth was analyzed by retention site, revealing depth-independent partitioning of colloids. At the pore-scale, dominance and overall saturation of all retention sites considered indicated that the solid-water interface and wedge-shaped regions associated with flow-stagnation (grain-to-grain contacts in saturated and air-water-solid triple points in unsaturated conditions) are the greatest contributors toward retention under the tested conditions. At the interface-scale, xDLVO energy profiles were in agreement with pore-scale observations. Our calculations suggest favorable interactions for colloids and solid-water interfaces and for weak flocculation (e.g., at flow-stagnation zones), but unfavorable interactions between colloids and air-water interfaces. Overall, we demonstrate that pore-structure plays a critical role in colloid immobilization and that Darcy-, pore- and interface-scales are consistent when the pore structure is taken into account.
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- 2022
4. Direct Measurements of the Forces between Silver and Mica in Humic Substance-Rich Solutions
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Patiño, Janis E, Kuhl, Tonya L, and Morales, Verónica L
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Aluminum Silicates ,Humic Substances ,Silver ,Solutions ,Environmental Sciences - Abstract
Deposition of engineered nanoparticles onto porous media from flowing suspensions is important for soil and groundwater quality. The deposition mechanism is controlled by interaction forces between particles and collectors. We investigated the origin and magnitude of opposing forces between silver and mica surfaces (representing nanosilver and sand grains) in solutions relevant to agricultural soils with direct measurements using a surface force apparatus. Solutions of variable NaNO3, Ca(NO3)2, and humic acid (HA) concentrations were used to differentiate individual contributing forces and quantify surface properties. The measured Hamaker constant for silver-water-mica was consistent with Lifshitz theory. Our results indicate that HA forms an adsorbed surface layer, but its charge, thicknesses, compressibility, and mass are significantly larger on mica than silver. Ca2+ primarily reduced the differences between the initially adsorbed HA layer properties on each surface, making them more similar. Force-distance profiles indicate that, when silver-mica systems were exposed to HA, osmotic-steric, electrostatic, and van der Waals forces dominate. Soft particle theory was deemed inappropriate for this system. Derjaguin's approximation was utilized to translate force measurements into interaction energy between nanosilver particles and mica collectors. We propose attachment efficiency estimates from measured surface properties, which suggest high particle mobility when nanosilver is applied to HA-rich agricultural soils with modest ionic strength.
- Published
- 2020
5. Morphology of Shear-Induced Colloidal Aggregates in Porous Media: Consequences for Transport, Deposition, and Re-entrainment
- Author
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Perez, Alejandro J, Patiño, Janis E, Soos, Miroslav, and Morales, Verónica L
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Hydrology ,Engineering ,Earth Sciences ,Colloids ,Filtration ,Fractals ,Particle Size ,Porosity ,Environmental Sciences - Abstract
Colloid deposition in granular media is relevant to numerous environmental problems. Classic filtration models assume a homogeneous pore space and largely ignore colloid aggregation. However, substantial evidence exists on the ubiquity of aggregation within porous media, suggesting that deposition is enhanced by it. This work studies the deposition process in relation to aggregate size and structure. We demonstrate that aggregation is induced at typical groundwater velocities by comparing the repulsive DLVO force between particle pairs to the hydrodynamic shear force opposing it. Column experiments imaged with high-resolution X-ray computed tomography are used to measure aggregate structure and describe their morphology probability distribution and spatial distribution. Aggregate volume and surface area are found to be power-law distributed, while Feret diameter is exponentially distributed with some flow rate dependencies caused by erosion and restructuring by the fluid shear. Furthermore, size and shape of aggregates are heterogeneous in depth, where a small number of large aggregates control the concentration versus depth profile shape. The range of aggregate fractal dimensions found (2.22-2.42) implies a high potential for restructuring or breaking during transport. Shear-induced aggregation is not currently considered in macroscopic models for particle filtration, yet is critical to consider in the processes that control deposition.
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- 2020
6. Relating mechanistic fate with spatial positioning for colloid transport in surface heterogeneous porous media
- Author
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Patiño, Janis E., Johnson, William P., and Morales, Verónica L.
- Published
- 2023
- Full Text
- View/download PDF
7. Recent advances in anomalous transport models for predicting contaminants in natural groundwater systems
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Bolster, Diogo, Roche, Kevin R, and Morales, Verónica L
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Chemical Engineering - Abstract
High degrees of spatial heterogeneity in hydrologic systems pose a major barrier for their protection and remediation. Dissolved and particulate contaminants are mixed and retained over timescales ranging from seconds to years due to their interactions with these structural heterogeneities. Over the last two decades, a new class of models has demonstrated its capacity to describe observed ‘anomalous transport’ behavior that is ubiquitous to nearly all flowing waters. The promise of these models lies in their potential for predicting transport using minimal parameters, while remaining faithful to the underlying complexity of the system. In this review, we highlight recent experimental studies that have improved our understanding of the structural controls of anomalous transport, as well as modeling studies that use these new insights to better predict contaminant fate.
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- 2019
8. Biofilms in 3D porous media: Delineating the influence of the pore network geometry, flow and mass transfer on biofilm development
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Carrel, Maxence, Morales, Verónica L, Beltran, Mario A, Derlon, Nicolas, Kaufmann, Rolf, Morgenroth, Eberhard, and Holzner, Markus
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Fluid Mechanics and Thermal Engineering ,Engineering ,Biofilms ,Hydrodynamics ,Porosity ,Rheology ,Stress ,Mechanical ,X-Ray Microtomography ,Biofilm ,Three-dimensional porous medium ,Three-dimensional particle tracking velocimetry ,X-ray micro computed tomography ,Wall shear stress ,Concentration boundary layer thickness ,Biofilm morphology ,Environmental Engineering - Abstract
This study investigates the functional correspondence between porescale hydrodynamics, mass transfer, pore structure and biofilm morphology during progressive biofilm colonization of a porous medium. Hydrodynamics and the structure of both the porous medium and the biofilm are experimentally measured with 3D particle tracking velocimetry and micro X-ray Computed Tomography, respectively. The analysis focuses on data obtained in a clean porous medium after 36 h of biofilm growth. Registration of the particle tracking and X-ray data sets allows to delineate the interplay between porous medium geometry, hydrodynamic and mass transfer processes on the morphology of the developing biofilm. A local analysis revealed wide distributions of wall shear stresses and concentration boundary layer thicknesses. The spatial distribution of the biofilm patches uncovered that the wall shear stresses controlled the biofilm development. Neither external nor internal mass transfer limitations were noticeable in the considered system, consistent with the excess supply of nutrient and electron acceptors. The wall shear stress remained constant in the vicinity of the biofilm but increased substantially elsewhere.
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- 2018
9. Correction: Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools
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Carrel, Maxence, Beltran, Mario A, Morales, Verónica L, Derlon, Nicolas, Morgenroth, Eberhard, Kaufmann, Rolf, and Holzner, Markus
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Inorganic Chemistry ,Chemical Sciences ,Physical Sciences ,General Science & Technology - Abstract
[This corrects the article DOI: 10.1371/journal.pone.0180374.].
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- 2018
10. Biofilm imaging in porous media by laboratory X-Ray tomography: Combining a non-destructive contrast agent with propagation-based phase-contrast imaging tools.
- Author
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Carrel, Maxence, Beltran, Mario A, Morales, Verónica L, Derlon, Nicolas, Morgenroth, Eberhard, Kaufmann, Rolf, and Holzner, Markus
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Biofilms ,Barium Sulfate ,Water ,Ferrous Compounds ,Fluorocarbon Polymers ,Contrast Media ,Imaging ,Three-Dimensional ,Tomography ,X-Ray ,Rheology ,Porosity ,General Science & Technology - Abstract
X-ray tomography is a powerful tool giving access to the morphology of biofilms, in 3D porous media, at the mesoscale. Due to the high water content of biofilms, the attenuation coefficient of biofilms and water are very close, hindering the distinction between biofilms and water without the use of contrast agents. Until now, the use of contrast agents such as barium sulfate, silver-coated micro-particles or 1-chloronaphtalene added to the liquid phase allowed imaging the biofilm 3D morphology. However, these contrast agents are not passive and potentially interact with the biofilm when injected into the sample. Here, we use a natural inorganic compound, namely iron sulfate, as a contrast agent progressively bounded in dilute or colloidal form into the EPS matrix during biofilm growth. By combining a very long source-to-detector distance on a X-ray laboratory source with a Lorentzian filter implemented prior to tomographic reconstruction, we substantially increase the contrast between the biofilm and the surrounding liquid, which allows revealing the 3D biofilm morphology. A comparison of this new method with the method proposed by Davit et al (Davit et al., 2011), which uses barium sulfate as a contrast agent to mark the liquid phase was performed. Quantitative evaluations between the methods revealed substantial differences for the volumetric fractions obtained from both methods. Namely, contrast agent-biofilm interactions (e.g. biofilm detachment) occurring during barium sulfate injection caused a reduction of the biofilm volumetric fraction of more than 50% and displacement of biofilm patches elsewhere in the column. Two key advantages of the newly proposed method are that passive addition of iron sulfate maintains the integrity of the biofilm prior to imaging, and that the biofilm itself is marked by the contrast agent, rather than the liquid phase as in other available methods. The iron sulfate method presented can be applied to understand biofilm development and bioclogging mechanisms in porous materials and the obtained biofilm morphology could be an ideal basis for 3D numerical calculations of hydrodynamic conditions to investigate biofilm-flow coupling.
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- 2017
11. Can pore-clogging by ash explain post-fire runoff?
- Author
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Stoof, Cathelijne R, Gevaert, Anouk I, Baver, Christine, Hassanpour, Bahareh, Morales, Verónica L, Zhang, Wei, Martin, Deborah, Giri, Shree K, and Steenhuis, Tammo S
- Subjects
hydraulic conductivity ,infiltration ,wildland fire ash ,Environmental Science and Management ,Ecology ,Forestry Sciences ,Forestry - Abstract
Ash plays an important role in controlling runoff and erosion processes after wildfire and has frequently been hypothesised to clog soil pores and reduce infiltration. Yet evidence for clogging is incomplete, as research has focussed on identifying the presence of ash in soil; the actual flow processes remain unknown. We conducted laboratory infiltration experiments coupled with microscope observations in pure sands, saturated hydraulic conductivity analysis, and interaction energy calculations, to test whether ash can clog pores (i.e. block pores such that infiltration is hampered and ponding occurs). Although results confirmed previous observations of ash washing into pores, clogging was not observed in the pure sands tested, nor were conditions found for which this does occur. Clogging by means of strong attachment of ash to sand was deemed unlikely given the negative surface charge of the two materials. Ponding due to washing in of ash was also considered improbable given the high saturated conductivity of pure ash and ash-sand mixtures. This first mechanistic step towards analysing ash transport and attachment processes in field soils therefore suggests that pore clogging by ash is unlikely to occur in sands. Discussion is provided on other mechanisms by which ash can affect post-fire hydrology. Journal compilation
- Published
- 2016
12. Reverse engineering of biochar
- Author
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Morales, Verónica L, Pérez-Reche, Francisco J, Hapca, Simona M, Hanley, Kelly L, Lehmann, Johannes, and Zhang, Wei
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Agricultural ,Veterinary and Food Sciences ,Biological Sciences ,Industrial Biotechnology ,Microbiology ,Agricultural Biotechnology ,Bioengineering ,Biomass ,Charcoal ,Confidence Intervals ,Engineering ,Hydrogen-Ion Concentration ,Internet ,Linear Models ,Physico-chemical properties ,Slow-pyrolysis ,Correlation networks ,Generalized Linear Models ,Web-tool ,Biotechnology ,Agricultural biotechnology ,Industrial biotechnology - Abstract
This study underpins quantitative relationships that account for the combined effects that starting biomass and peak pyrolysis temperature have on physico-chemical properties of biochar. Meta-data was assembled from published data of diverse biochar samples (n=102) to (i) obtain networks of intercorrelated properties and (ii) derive models that predict biochar properties. Assembled correlation networks provide a qualitative overview of the combinations of biochar properties likely to occur in a sample. Generalized Linear Models are constructed to account for situations of varying complexity, including: dependence of biochar properties on single or multiple predictor variables, where dependence on multiple variables can have additive and/or interactive effects; non-linear relation between the response and predictors; and non-Gaussian data distributions. The web-tool Biochar Engineering implements the derived models to maximize their utility and distribution. Provided examples illustrate the practical use of the networks, models and web-tool to engineer biochars with prescribed properties desirable for hypothetical scenarios.
- Published
- 2015
13. Filtration and transport of heavy metals in graphene oxide enabled sand columns
- Author
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Ding, Zhuhong, Hu, Xin, Morales, Verónica L, and Gao, Bin
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Graphene oxide ,Fixed-bed column ,Filtration ,Cu ,Pb ,Chemical Engineering ,Civil Engineering ,Environmental Engineering - Abstract
A fixed-bed sand column with graphene oxide (GO) layer was used to remove heavy metals (Cu(II) and Pb(II)) from an aqueous solution injected under steady flow. Due to the time constrained kinetic process of heavy metal sorption to GO, removal efficiency was affected by the injection flow rate. When injection flow rate changed from 1 to 5mLmin-1, the removal efficiency of the two metals decreased from 15.3% to 10.3% and from 26.7% to 19.0% for Cu(II) and Pb(II), respectively. Provided a fixed concentration of heavy metals in the injected flow, an increase in GO in column from 10 to 30mg resulted in an sharp increase in the removal efficiency of Pb(II) from 26.7% to 40.5%. When Cu(II) and Pb(II) were applied simultaneously, the removal efficiency of the two metals was lower than when applied by individually. GO-sand column performance was much better for the removal of Pb(II) than for Cu(II) in each corresponding treatment. When breakthrough curve (BTC) data were simulated by the convection-dispersion-reaction (CDER) model, the fittings for Cu in every treatment were better than that of Pb in corresponding treatment. Considering the small amount of GO used to enable the sand columns that resulted in a great increase in k value, compared to the GO-free sand columns, the authors propose GO as an effective adsorption media in filters and reactive barriers to remove Pb(II) from flowing water.
- Published
- 2014
14. Effect of Hydrofracking Fluid on Colloid Transport in the Unsaturated Zone
- Author
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Sang, Wenjing, Stoof, Cathelijne R, Zhang, Wei, Morales, Verónica L, Gao, Bin, Kay, Robert W, Liu, Lin, Zhang, Yalei, and Steenhuis, Tammo S
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Hydrology ,Environmental Sciences ,Earth Sciences ,Soil Sciences ,Chlorides ,Colloids ,Energy-Generating Resources ,Microscopy ,Rheology ,Silicon Dioxide ,Soil ,Solutions ,Water - Abstract
Hydraulic fracturing is expanding rapidly in the US to meet increasing energy demand and requires high volumes of hydrofracking fluid to displace natural gas from shale. Accidental spills and deliberate land application of hydrofracking fluids, which return to the surface during hydrofracking, are common causes of environmental contamination. Since the chemistry of hydrofracking fluids favors transport of colloids and mineral particles through rock cracks, it may also facilitate transport of in situ colloids and associated pollutants in unsaturated soils. We investigated this by subsequently injecting deionized water and flowback fluid at increasing flow rates into unsaturated sand columns containing colloids. Colloid retention and mobilization was measured in the column effluent and visualized in situ with bright field microscopy. While
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- 2014
15. Quantification of Colloid Retention and Release by Straining and Energy Minima in Variably Saturated Porous Media
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Sang, Wenjing, Morales, Verónica L, Zhang, Wei, Stoof, Cathelijne R, Gao, Bin, Schatz, Anna Lottie, Zhang, Yalei, and Steenhuis, Tammo S
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Hydrology ,Environmental Sciences ,Earth Sciences ,Soil Sciences ,Colloids ,Electrophoretic Mobility Shift Assay ,Kinetics ,Osmolar Concentration - Abstract
The prediction of colloid transport in unsaturated porous media in the presence of large energy barrier is hampered by scant information of the proportional retention by straining and attractive interactions at surface energy minima. This study aims to fill this gap by performing saturated and unsaturated column experiments in which colloid pulses were added at various ionic strengths (ISs) from 0.1 to 50 mM. Subsequent flushing with deionized water released colloids held at the secondary minimum. Next, destruction of the column freed colloids held by straining. Colloids not recovered at the end of the experiment were quantified as retained at the primary minimum. Results showed that net colloid retention increased with IS and was independent of saturation degree under identical IS and Darcian velocity. Attachment rates were greater in unsaturated columns, despite an over 3-fold increase in pore water velocity relative to saturated columns, because additional retention at the readily available air-associated interfaces (e.g., the air-water-solid [AWS] interfaces) is highly efficient. Complementary visual data showed heavy retention at the AWS interfaces. Retention by secondary minima ranged between 8% and 46% as IS increased, and was greater for saturated conditions. Straining accounted for an average of 57% of the retained colloids with insignificant differences among the treatments. Finally, retention by primary minima ranged between 14% and 35% with increasing IS, and was greater for unsaturated conditions due to capillary pinning.
- Published
- 2013
16. Deposition and transport of graphene oxide in saturated and unsaturated porous media
- Author
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Liu, Lin, Gao, Bin, Wu, Lei, Morales, Verónica L, Yang, Liuyan, Zhou, Zuhao, and Wang, Hao
- Subjects
Graphene oxide ,Porous media ,Surface deposition ,Air-water interface ,Transport modeling ,Chemical Engineering ,Civil Engineering ,Environmental Engineering - Abstract
In this work, sand and bubble column experiments were conducted to explore the deposition mechanisms of graphene oxide (GO) particles in porous media with various combinations of moisture content and ionic strength. Sand column experimental results indicated that retention and transport of GO in porous media were strongly dependent on solution ionic strength. Particularly, GO showed high mobility under low ionic strength conditions in both saturated and unsaturated porous media. Increasing ionic strength dramatically increased the retention of GO particles in porous media, mainly through secondary-minimum deposition as indicated in the XDLVO interaction energy profiles. Recovery rates of GO in unsaturated sand columns were lower than that in saturated columns under the same ionic strength conditions, suggesting moisture content also played an important role in the retention of GO in porous media. Findings from the bubble column experiments showed that the GO did not attach to the air-water interface, which is consistent with the XDLVO predictions. Additional retention mechanisms, such as film straining, thus could be responsible to the reduced mobility of GO in unsaturated porous media. The experimental data of GO transport through saturated and unsaturated porous media could be accurately simulated by an advection-dispersion-reaction model. © 2013 Elsevier B.V..
- Published
- 2013
17. Removal of sulfamethoxazole and sulfapyridine by carbon nanotubes in fixed-bed columns
- Author
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Tian, Yuan, Gao, Bin, Morales, Verónica L., Chen, Hao, Wang, Yu, and Li, Hui
- Published
- 2013
- Full Text
- View/download PDF
18. Methods of using carbon nanotubes as filter media to remove aqueous heavy metals
- Author
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Tian, Yuan, Gao, Bin, Morales, Verónica L., Wu, Lei, Wang, Yu, Muñoz-Carpena, Rafael, Cao, Can, Huang, Qingguo, and Yang, Liuyan
- Published
- 2012
- Full Text
- View/download PDF
19. Pore-Scale Hydrodynamics in a Progressively Bioclogged Three-Dimensional Porous Medium: 3-D Particle Tracking Experiments and Stochastic Transport Modeling
- Author
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Carrel, M., Morales, Verónica L., Dentz, Marco, Derlon, N., Morgenroth, E., Holzner, Markus, Carrel, M., Morales, Verónica L., Dentz, Marco, Derlon, N., Morgenroth, E., and Holzner, Markus
- Abstract
Biofilms are ubiquitous bacterial communities that grow in various porous media including soils, trickling, and sand filters. In these environments, they play a central role in services ranging from degradation of pollutants to water purification. Biofilms dynamically change the pore structure of the medium through selective clogging of pores, a process known as bioclogging. This affects how solutes are transported and spread through the porous matrix, but the temporal changes to transport behavior during bioclogging are not well understood. To address this uncertainty, we experimentally study the hydrodynamic changes of a transparent 3-D porous medium as it experiences progressive bioclogging. Statistical analyses of the system's hydrodynamics at four time points of bioclogging (0, 24, 36, and 48 h in the exponential growth phase) reveal exponential increases in both average and variance of the flow velocity, as well as its correlation length. Measurements for spreading, as mean-squared displacements, are found to be non-Fickian and more intensely superdiffusive with progressive bioclogging, indicating the formation of preferential flow pathways and stagnation zones. A gamma distribution describes well the Lagrangian velocity distributions and provides parameters that quantify changes to the flow, which evolves from a parallel pore arrangement under unclogged conditions, toward a more serial arrangement with increasing clogging. Exponentially evolving hydrodynamic metrics agree with an exponential bacterial growth phase and are used to parameterize a correlated continuous time random walk model with a stochastic velocity relaxation. The model accurately reproduces transport observations and can be used to resolve transport behavior at intermediate time points within the exponential growth phase considered.
- Published
- 2018
20. Pore-scale hydrodynamics in a progressively bio-clogged three-dimensional porous medium: 3D particle tracking experiments and stochastic transport modeling
- Author
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Carrel, M., Morales, Verónica L., Dentz, Marco, Derlon, N., Morgenroth, E., Holzner, Markus, Carrel, M., Morales, Verónica L., Dentz, Marco, Derlon, N., Morgenroth, E., and Holzner, Markus
- Published
- 2018
21. Stochastic dynamics of intermittent pore-scale particle motion in three–dimensional porous media: Experiments and theory
- Author
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Morales, Verónica L., Dentz, Marco, Willmann, Matthias, Holzner, Markus, Morales, Verónica L., Dentz, Marco, Willmann, Matthias, and Holzner, Markus
- Published
- 2017
22. Intermittent Lagrangian velocities and accelerations in three-dimensional porous medium flow
- Author
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European Research Council, Holzner, Markus, Morales, Verónica L., Willmann, Matthias, Dentz, Marco, European Research Council, Holzner, Markus, Morales, Verónica L., Willmann, Matthias, and Dentz, Marco
- Abstract
Intermittency of Lagrangian velocity and acceleration is a key to understanding transport in complex systems ranging from fluid turbulence to flow in porous media. High-resolution optical particle tracking in a three-dimensional (3D) porous medium provides detailed 3D information on Lagrangian velocities and accelerations. We find sharp transitions close to pore throats, and low flow variability in the pore bodies, which gives rise to stretched exponential Lagrangian velocity and acceleration distributions characterized by a sharp peak at low velocity, superlinear evolution of particle dispersion, and double-peak behavior in the propagators. The velocity distribution is quantified in terms of pore geometry and flow connectivity, which forms the basis for a continuous-time random-walk model that sheds light on the observed Lagrangian flow and transport behaviors. ©2015 American Physical Society.
- Published
- 2015
23. Filtration and transport of heavy metals in graphene oxide enabled sand columns
- Author
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Ding, Zhuhong, primary, Hu, Xin, additional, Morales, Verónica L., additional, and Gao, Bin, additional
- Published
- 2014
- Full Text
- View/download PDF
24. Deposition and transport of graphene oxide in saturated and unsaturated porous media
- Author
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Liu, Lin, primary, Gao, Bin, additional, Wu, Lei, additional, Morales, Verónica L., additional, Yang, Liuyan, additional, Zhou, Zuhao, additional, and Wang, Hao, additional
- Published
- 2013
- Full Text
- View/download PDF
25. Grain Surface‐Roughness Effects on Colloidal Retention in the Vadose Zone
- Author
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Morales, Verónica L., primary, Gao, Bin, additional, and Steenhuis, Tammo S., additional
- Published
- 2009
- Full Text
- View/download PDF
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