Three-Dimensional Nickel Ion Transport through Porous Media Using Magnetic Resonance Imaging

Herrmann, Karl‐Heinz; Pohlmeier, Andreas; Wiese, S.; Shah, NJ; Nitzsche, Olaf; Vereecken, Harry

doi:10.2134/jeq2002.0506

Cited by 15 publications

(9 citation statements)

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“…for the data analyses, an IdL-Routine for the velocity field calculation was adapted after Herrmann et al (2002a). The signal distribution of the tracer along a particular vertical is supposed to be Gaussian.…”

Section: Methodsmentioning

confidence: 99%

“…mRI allows complex insights into the processes occurring within the porous medium. It has been used for tracing the water within the sample (votrubová et al 2003), detecting the flow process during the infiltration-outflow experiments (Sněhota & Císlerová 2005), estimating the temporal changes of the water content during the infiltration experiment within undisturbed heterogeneous soil samples in 1d or 2d mRI (amin et al 1997; votrubová et al 2003), investigating the transport processes with the use of various tracers (Herrmann et al 2002a;Pohlmeier et al 2008), and many others. above that, 3d imaging can be done (Posadas et al 1996;Herrmann et al 2002a, b).…”

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confidence: 99%

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Tracer experiments within composite soil column investigated by MRI

Jelínková¹,

Cı́slerová²,

Pohlmeier³

et al. 2010

Soil & Water Res.

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Abstract:The magnetic resonance imaging (mRI) technique was used for the visualisation and interpretation of flow paths. a set of tracer-infiltration experiments was performed on soil columns filled with packed homogeneous sand and with a composite sand-soil system. The flow paths were visualised using a tracer-solution containing ni(nO 3 ) 2 which is characterised by relaxation times different from that of the infiltrating water. The tracer pulse was added under hydraulic steady state conditions. Small disturbances in the tracer front were observed during the breakthrough in the case of a homogeneous sample. more pronounced effects were seen with the composite sample. The vertical components of the velocity fields were evaluated for the experiments presented. The irregularities in the tracer front and in the velocity fields were in this case attributed to the preferential flow phenomena in combination with air bubble entrapment. Beside that, two consecutive tracer pulses were performed with the aim of testing the potential influence of the different solute concentrations on the adsorption power. Both concentrations had negligible impacts on the acquired image. The presented results are constrained by the limits of the described technology; further investigations are being carried out using more advanced equipment.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Tracer experiments within composite soil column investigated by MRI

Jelínková¹,

Cı́slerová²,

Pohlmeier³

et al. 2010

Soil & Water Res.

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“…Among other new techniques, Magnetic Resonance Imaging (MRI) has been proposed to assess the spatial distribution of water and metal ions in porous media (Herrmann et al 2002;Pierret et al 2003;Moradi et al 2008). The presence of paramagnetic ions and molecules in a solution affects the spin vector relaxation times (longitudinal relaxation time T 1 and transverse relaxation time T 2 ) of water protons ( 1 H).…”

Section: Introductionmentioning

confidence: 99%

Analysis of nickel concentration profiles around the roots of the hyperaccumulator plant Berkheya coddii using MRI and numerical simulations

et al. 2009

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Investigations of soil-root interactions are hampered by the difficult experimental accessibility of the rhizosphere. Here we show the potential of Magnetic Resonance Imaging (MRI) as a non-destructive measurement technique in combination with numerical modelling to study the dynamics of the spatial distribution of dissolved nickel (Ni 2+ ) around the roots of the nickel hyperaccumulator plant Berkheya coddii. Special rhizoboxes were used in which a root monolayer had been grown, separated from an adjacent inert glass bead packing by a nylon membrane. After applying a Ni 2+ solution of 10 mg l −1 , the rhizobox was imaged repeatedly using MRI. The obtained temporal sequence of 2-dimensional Ni 2+ maps in the vicinity of the roots showed that Ni 2+ concentrations increased towards the root plane, revealing an accumulation pattern. Numerical modelling supported the Ni 2+ distributions to result from advective water flow towards the root plane, driven by transpiration, and diffusion of Ni 2+ tending to eliminate the concentration gradient. With the model, we could study how the accumulation pattern of Ni 2+ in the root zone transforms into a depletion pattern depending on transpiration rate, solute uptake rate, and Ni 2+ concentration in solution.

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“…A standard spin echo (SE) sequence provides images with moderate T 1 and T 2 weighting. At relatively small concentrations of a paramagnetic species, the relaxivity, 1/T 1 , is proportional to concentration (Van As & van Dusschoten, 1997;Herrmann et al, 2002b;Oswald et al, 2002;Nestle et al, 2003a). Therefore, in T 1 -weighted images, acquired with sufficiently short repetition times, image intensity will be proportional to 1/T 1 , after dealing with the dependency of the image intensity to T 2 changes (Pearl et al, 1991;Nestle et al, 2003b).…”

Section: Introductionmentioning

confidence: 99%

Magnetic resonance imaging methods to reveal the real‐time distribution of nickel in porous media

Moradi

Oswald

Massner

et al. 2008

European J Soil Science

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Direct and non-destructive measurement of the sorption, diffusion and mobility of ions and molecules in porous media has applications in industry and environmental science. We used magnetic resonance imaging (MRI) to visualize the dynamic distribution of paramagnetic nickel (Ni þ2 ) ions in porous media. Various MRI sequences were tested to image Ni 2þ at small concentrations. Noisy gradient echo images had poor contrast between samples containing various Ni 2þ concentrations. Turbo spin echo and spoiled gradient echo images showed a linear relation between Ni 2þ concentrations and signal intensity over a wide range of concentrations. Spoiled gradient echo images resolved Ni 2þ concentrations (down to 30 mg litre À1 ) better than turbo spin echo images. However, for smaller concentrations, uncertainty in intensity values increased. A T 1 measurement, obtained using an inversion recovery sequence, showed a linear correlation between T 1 and Ni 2þ concentration down to 1.5 mg litre À1 . In a glass bead medium with an ion exchange resin as an Ni sink, the real-time development of the Ni 2þ depletion zone around the resin, as Ni was sorbed into the resin, was imaged by T 1 mapping. A spatial resolution of 0.58 mm and a temporal resolution of less than a minute were achieved. The two-dimensional Ni 2þ gradient that was determined from MRI agreed well with geochemical modelling results. The results of this study showed that MRI, in particular T 1 mapping, can quantify microscale behaviour of paramagnetic species in porous media. However, ferromagnetic components that naturally occur in most soils can easily disturb the MRI signal.

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Three-Dimensional Nickel Ion Transport through Porous Media Using Magnetic Resonance Imaging

Cited by 15 publications

References 0 publications

Tracer experiments within composite soil column investigated by MRI

Tracer experiments within composite soil column investigated by MRI

Analysis of nickel concentration profiles around the roots of the hyperaccumulator plant Berkheya coddii using MRI and numerical simulations

Magnetic resonance imaging methods to reveal the real‐time distribution of nickel in porous media

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