Pottasium Exchange as Affected by Cation Size, Ph, and Mineral Structure

Rich, C. I.; Black, W. R.

doi:10.1097/00010694-196406000-00004

Cited by 120 publications

(82 citation statements)

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“…It has been indicated that K selectivity in clay minerals followed the order of mica> Vt~Mt (Rich 1968). In this study, Vt compared to Mt showed a higher K and NH 4 selectivity over Ca.…”

Section: K/ca Adsorption Isothermssupporting

confidence: 46%

K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

Saha

Taniguchi

Sakurai

2001

Soil Science and Plant Nutrition

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“…It has been indicated that K selectivity in clay minerals followed the order of mica> Vt~Mt (Rich 1968). In this study, Vt compared to Mt showed a higher K and NH 4 selectivity over Ca.…”

Section: K/ca Adsorption Isothermssupporting

confidence: 46%

K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

Saha

Taniguchi

Sakurai

2001

Soil Science and Plant Nutrition

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“…The presence of hydroxy-cation islands tend to prop open the silicate layers and inhibit K fixation in vermiculite (Rich, 1960a) and in soil clays that contain vermiculite (Rich, 1960b) may affect the selectivity of ions Rich and Black, 1964) by permitting entry of K-size ions into partially opened mica layers, without hindrance by collapse at the edges of the mineral.…”

Section: Effect On Ion Fixation and Selectivitymentioning

confidence: 99%

Hydroxy Interlayers in Expansible Layer Silicates

Rich

1968

Clays and clay miner.

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314

187

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“…However, Cs is found to be strongly associated and resistant to removal from certain sites on phyllosilicate minerals. While Cs only interacts weakly with basal surface and edge terminations of sheet silicate layers, partially delaminated zones adjacent to the edge termination of silicate sheets, socalled frayed-edge sites (Jackson, 1963;Rich and Black, 1964), provide sterically selective interlayer environments where Cs is held tightly with a high preference over many common compatible interlayer species (e.g. Cremers et al, 1988;Comans et al, 1991;De Preter et al, 1991;Comans and Hockley, 1992;Gutierrez and Fuentes, 1996;Maes et al, 1999;Bradbury and Baeyens, 2000).…”

Section: Introductionmentioning

confidence: 99%

The CS/K Exchange in Muscovite Interlayers: An Ab Initio Treatment

Rosso

Rustad

Bylaska

2001

Clays and clay miner.

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Abstract--Plane-wave pseudopotential total energy calculations have been applied to investigate the structure and energetics of the Cs/K exchange into interlayer sites in muscovite mica. Novel muscovite structures were designed to isolate the effects of 2:1 layer charge, cation size/interlayer site shape, and tetrahedral A1/Si substitutions on the exchange. All atom and cell-parameter optimizations were performed with the intention to mimic the constant pressure, non-isovolumetric exchange conditions thought to be found at frayed-edge sites. Under conditions where the cell parameters are allowed to relax, the overall Cs/K exchange reaction is surprisingly close to isoenergetic. The forward reaction is more strongly favored with increasing layer charge. For the condition of zero layer charge and no interlayer site distortion, the difference in the optimal interlayer spacing for Cs relative to K is very small, indicating a baseline indifference of the muscovite structure to cation size. The presence of 2:1 layer charge or tetrahedral rotations arising from A1/Si substitutions clearly change this outcome. Analysis of the dependence of the interlayer spacing on layer charge shows that while the spacing collapses with increasing layer charge for K as the interlayer cation, the reverse is true for Cs. We attribute the contrasting behavior to inherent differences in the ability of these cations to screen 2:1 layer-layer repulsions. Such effects might be involved during exchange at frayed-edge sites where interlayer spacings are increased. This is known, from experiment, to be very selective for Cs. Overall, the exchange energetics are so low that the Cs/K exchange rate and degree of irreversibility are likely to be dominated by diffusion kinetics.

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Pottasium Exchange as Affected by Cation Size, Ph, and Mineral Structure

Cited by 120 publications

References 0 publications

K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

Hydroxy Interlayers in Expansible Layer Silicates

The CS/K Exchange in Muscovite Interlayers: An Ab Initio Treatment

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Pottasium Exchange as Affected by Cation Size, Ph, and Mineral Structure

Cited by 120 publications

References 0 publications

K/Ca and NH4/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

K/Ca and NH4/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

Hydroxy Interlayers in Expansible Layer Silicates

The CS/K Exchange in Muscovite Interlayers: An Ab Initio Treatment

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Product

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K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites

K/Ca and NH₄/Ca selectivity of hydroxyaluminum-interlayered vermiculite and montmorillonite: Contribution from regular and frayed edge exchange sites