Determining Millimeter‐Scale Maps of Cation Exchange Capacity at Macropore Surfaces in Bt Horizons

Leue, Martin; Beck‐Broichsitter, Steffen; Felde, Vincent J.M.N.L.; Gerke, Horst H.

doi:10.2136/vzj2018.08.0162

Cited by 9 publications

(24 citation statements)

References 43 publications

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“…Thus, the actual three‐dimensional soil water content distribution within the soil clod may differ from the simulated one‐dimensional distribution. Consequently, submillimeter‐scaled maps of the actual water content, the wettability, and the amount and accessibility of sorption sites (Leue et al., 2019) would help to better explain deviations between applied and recovered masses.…”

Section: Discussionmentioning

confidence: 99%

Macropore–matrix mass transfer of reactive solutes quantified by fluorescence imaging

Haas

Leue

Ellerbrock

et al. 2020

Vadose Zone Journal

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Horizontal infiltration experiments with a fluorescent dye (e.g., Na-fluorescein) potentially allow the quantification of the macropore-matrix mass transfer of reactive solutes through coated macropore surfaces. The objectives were (a) to determine the movement and map the spatial mass distributions of a reactive and fluorescent dye (i.e., Na-fluorescein) at the millimeter scale during horizontal tracer application to the intact structural surface of a soil aggregate, and (b) to validate the method by comparing total masses as quantified with Fluorescence imaging with total applied dye masses. For the quantification of dissolved masses of dye, millimeter-scaled distributed water contents obtained from horizontal flow simulation using Hydrus-1D were multiplied with mapped dye solution concentrations. The spatial distribution of dye concentrations was visualized and quantified with a fluorescence imaging technique at a pixel resolution length of ∼100 μm. Submillimeter-scaled distribution maps of adsorbed dye concentrations were derived using the calibrated Freundlich adsorption model. The sorption isotherm predicted that most of the dye was adsorbed to soil. In total, 1,366 μg of dye was transferred through the coated matrix block, of which 1,181 μg was adsorbed to soil. The applicability of the method was validated by comparing applied and recovered Na-fluorescein masses, which corresponded relatively closely. Although the test of the approach presented here was limited by uncertainties regarding the local distributions of water contents and bulk density, the method could be applied to map two-dimensional horizontal distributions of dye in an intact soil clod for quantifying macropore-matrix mass transfer of the reactive solute.

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Section: Discussionmentioning

confidence: 99%

Macropore–matrix mass transfer of reactive solutes quantified by fluorescence imaging

Haas

Leue

Ellerbrock

et al. 2020

Vadose Zone Journal

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“…The calculation of absolute OC and CEC values of single, disconnected pores (“pinholes,” PIN) was not possible in the same way, since the pinholes could not be identified in the XRCT 3D images due to the limited spatial resolution. For an indirect determination of the proportion of PIN in the OC and CEC of the soil cores, a relation ( f , dimensionless) was used (Leue, Beck‐Broichsitter, et al., 2019):

f_{normalOC} = \frac{()(, normalO C_{bulk} - normalO C_{Mx})}{()(, normalO C_{PIN} - normalO C_{Mx})}

f_{normalCEC} = \frac{()(, normalCE C_{bulk} - normalCE C_{Mx})}{()(, normalCE C_{PIN} - normalCE C_{Mx})}

…”

Section: Methodsmentioning

confidence: 99%

“…(2018) and Leue, Beckbroichsitter, et al. (2019) manually separated the outermost layer of intact macropore surfaces from Bt horizons. The OC content and CEC values were determined in the separated material, and their two‐dimensional (2D) spatial distribution along intact macropore surfaces was determined using diffusive infrared spectroscopy (“DRIFT mapping”).…”

Section: Introductionmentioning

confidence: 99%

Volume‐related quantification of organic carbon content and cation exchange capacity of macropore surfaces in Bt horizons

Leue

Uteau

Peth

et al. 2020

Vadose Zone Journal

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In structured soils, earthworm burrows, root channels, shrinkage cracks, and interaggregate spaces form complex macropore networks relevant for preferential transport, turnover processes, and root growth. Macropore walls are often coated with organomineral material, which determine physicochemical properties such as wettability, sorption, and the cation exchange capacity (CEC). The objective here was to identify volume-averaged mean macropore coating properties of larger intact soil cores (∼7,500 cm 3) from Bt horizons of Luvisols developed from loess and glacial till. The quantification of organic C (OC) content and CEC of macropore surfaces was based on three-dimensional images of X-ray computed tomography (XRCT) of 231-μm voxel resolution and a vesselness procedure to distinguish between biopores and cracks. Macropore surface areas were combined with millimeter-scaled data of OC contents and CEC of macropore coating material. The surface of macropores that accounted for 5.6 % (loess-Bt) and 4.6 % (till-Bt) of the samples' volumes represented approximately one-third of the OC content and CEC of the bulk soil. Among the macropores, surfaces of larger biopores contributed most to OC content of the soil cores. The contribution of coated cracks and pinhole fillings to OC content was larger for the till-Bt than for the loess-Bt. Locally higher OC contents and CEC values emphasize the role of macropore surfaces in Bt horizons of Luvisols as geochemical hotspots and for mass exchange, especially during preferential flow and transport. Volume-based coating properties may help improving macroscopic-scale two-domain flow and transport models.

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“…So, with increase in clay-organic coating in the soil it will improve the void ratio which is related with the CEC of soil. With increased void ratio of soil, the macrospores served as special flow path which will decrease the formation damage and could reduce the reservoir impairment and other engineering practices like drainage, water conservation, etc [1]. So, in this case with increase in CEC the permeability of soil increases with its ability to conduct oil and gas for its production.…”

Section: Industrymentioning

confidence: 99%

“…An ion exchange phenomenon is the combination of both cation exchange and anion exchange. The ion exchange capacity is the amount of total charge developed in a charged surface colloidal clay layer lattice, where ions from the soil solution has the capacity to interchange with the ions attached in that clay lattice [1]. The ion exchange capacity is the sum of cation exchange capacity (CEC) (capacity of solids to adsorb and exchange cations) and anion exchange capacity (AEC) (capacity of solids to adsorb and exchange anions).…”

Section: Introductionmentioning

confidence: 99%

Ion Exchange: The Most Important Chemical Reaction on Earth after Photosynthesis

Meetei

Devi

Chanu

2020

IRJPAC

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Ion exchange is the interchange of equivalent amount of ions from the solution with ions which are swarming in a boundary of charged surface in equilibrium. It is developed due to the presence of charge in the soil colloids or layer lattice clay minerals. The source of charge developed in the colloidal surface site of soil is mainly from two processes viz. isomorphous substitution and pH dependent charge. The charge can be positive or negative due to the exchange reaction in the layer lattice. The ion exchange capacity is the sum of cation exchange capacity (CEC) and anion exchange capacity (AEC). It depends on the types of soil and the amount of charge present in the layer lattice colloidal structure. With high negative charge in the lattice surface the CEC increases and with positive charge the AEC. Ions with higher charge have larger affinity to adsorbed more strongly than lower. Ion exchange capacity in soil has the ability to retained more nutrients in the form of cations or anions making available to plant for a long time which improved the fertility of soil. Leaching loss of different nutrients from the soil is reduced by holding different ions. Ion exchange processes have been widely used for heavy metal removal for waste water treatment and water purification because of its high remedial capacity, high removal efficiency and fast kinetic. Due to its applications in agriculture, environmental management, industries, waste water treatment in mining industries, laboratory, nanotechnology, geotechnical and other soil reclamation processes it is considered as the second most important reaction in the globe after photosynthesis.

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Determining Millimeter‐Scale Maps of Cation Exchange Capacity at Macropore Surfaces in Bt Horizons

Cited by 9 publications

References 43 publications

Macropore–matrix mass transfer of reactive solutes quantified by fluorescence imaging

Macropore–matrix mass transfer of reactive solutes quantified by fluorescence imaging

Volume‐related quantification of organic carbon content and cation exchange capacity of macropore surfaces in Bt horizons

Ion Exchange: The Most Important Chemical Reaction on Earth after Photosynthesis

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