Praktische Verwendung und Einsatzmöglichkeiten von Tonen

Lagaly, G.

doi:10.1007/978-3-642-72488-6_9

Cited by 4 publications

(2 citation statements)

References 151 publications

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“…The interaction of primary n-alkylammonium ions with 2:1 clay minerals provides a simple and effective method for layer charge determination (Lagaly, 1994). The influence of organic compounds on the flow behavior of clay minerals is important in many practical applications (Lagaly, 1993a). The organic compounds can change the transport of clay minerals in soils and affect the soil mechanics (Wienberg, 1990;Hasenpatt et al, 1989;Schmidt and Lagaly, 1999).…”

Section: Introductionmentioning

confidence: 99%

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

Penner

Lagaly

2000

Clays and clay miner.

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Abstracts-The colloidal state (stable, coagulated, or gel-like) and the theological properties of Na-rich montmorillonite (Wyoming) dispersions are strongly influenced by organic cations. This effect is shown for homologous organic cations: alkyl trimethylammonium ions, paraquat, diquat, alkyl bispyridinium ions, and the triphenylmethane dyes crystal violet, methyl green, and tris (tri-methylammonium phenyl) methane chloride. The critical coagulation concentrations, cK, are small (often < 1 mmol/L) because the cations are enriched in the Stern layer and influence the solvent structure near the surface. The strong adsorption of the counterions at the clay-mineral surface causes CK values to increase with the solid content. Charge reversal (recharging) of the particles was observed with the longer chain alkyl trimethylammonium ions, dodecyl bispyridinium ions, and crystal violet. Other cations reduced the electrophoretic mobility to zero but positive particle charges were not observed.The plastic viscosity increased sharply at the critical coagulation concentration and showed a minimum slightly below cK, which was caused by the electroviscous effect. Yield values were developed at concentrations above CK. In most cases, yield values reached a plateau where the amount of organic cations was -0.5 mmol/g, i.e., about half of the cation-exchange capacity. The cK values decreased with increasing hydrophobicity of homologous compounds, but the yield value showed maxima at intermediate chain lengths. The yield value of several 0.5% dispersions was high, e.g., dodecyl trimethylammonium ions, 71 Pa; paraquat, 100 Pa; diquat, 42 Pa; hexyl bispyridinium ions, 53 Pa (vs. Ca 2 § 0.2 Pa; AP +, 0.7 Pa). The storage modulus as a function of the number of organic cations changed in a similar way as the yield value, and high values were observed (e.g., dodecyl trimethylammonium ions, hexyl bispyridinium ions: 1000 Pa, paraquat: >4000 Pa). Thus, dispersions with high viscosity, yield value, and pronounced viscoelasticity are obtained by coagulating Na-rich montmorillonite dispersions with organic cations.

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Section: Introductionmentioning

confidence: 99%

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

Penner

Lagaly

2000

Clays and clay miner.

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“…The Na-bentonite was prepared by mixing of 1 kg natural bentonite with 50 g Na 2 CO 3 and 1 l water. The Ca 2+ -ions were exchanged and calcite CaCO 3 precipitated [18]. Then the clay was dried at 105 • C and milled.…”

Section: Methodsmentioning

confidence: 99%

Positron emission tomography for modelling of geochemical transport processes in clay

Richter¹,

Gründig²,

Zieger³

et al. 2005

Radiochimica Acta

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The transport of water and salt solutions in unsaturated clay and clay rock was measured using the positron emission tomography (PET). The experimental device is described. KF marked with 18 F was used as conservative hydrodynamic tracer to image the flow profiles at different times. Homogeneous and heterogeneous flow regimes were identified. Hydrodynamic model parameters could be determined for the homogeneous regime. The results demonstrate the advantage of PET measurements for investigations of transport processes in geological matrices. They yield quantitative values of the spatial distribution in regard to the flow pattern inside the samples which are important for the validation and parameter estimation of geochemical transport models.

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Bacteria-Mineral Colloid Interactions in Biofilms: An Ultrastructural and Microanalytical Approach

Lünsdorf

2015

Springer Protocols Handbooks

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Praktische Verwendung und Einsatzmöglichkeiten von Tonen

Cited by 4 publications

References 151 publications

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

Influence of Organic and Inorganic Salts on the Coagulation of Montmorillonite Dispersions

Positron emission tomography for modelling of geochemical transport processes in clay

Bacteria-Mineral Colloid Interactions in Biofilms: An Ultrastructural and Microanalytical Approach

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