Estimating the fully developed diffuse double layer thickness from the bulk electrical conductivity in clay

Mojid, M. A.; Cho, H.

doi:10.1016/j.clay.2006.06.002

Cited by 42 publications

(12 citation statements)

References 17 publications

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“…The water in the clay sediments can be held either by electro-chemical forces or as pore water. Within the layer of bound water, a number of positively charged ions are embedded which balance the negative charges on the clay particles by forming diffuse double layers (DDL; Mojid and Cho, 2006). The thickness of these DDLs is an important controlling factor for the structural development, hydraulic conductivity, and other physico-chemical and mechanical properties of soils (Fukue et al, 1999(Fukue et al, , 2001.…”

Section: Discussionmentioning

confidence: 99%

“…The thickness of these DDLs is an important controlling factor for the structural development, hydraulic conductivity, and other physico-chemical and mechanical properties of soils (Fukue et al, 1999(Fukue et al, , 2001. When sea water flows into the saltmarsh the DDLs can be fully developed and provide the highest electrical conductivity of the clay (Mojid and Cho, 2006). This change in thickness of the DDL will further influence the bonds between particles.…”

Section: Discussionmentioning

confidence: 99%

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Creek enlargement in a low‐energy degrading saltmarsh in southern England

Collins

Thompson

2010

Earth Surf Processes Landf

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A low-energy saltmarsh in the Beaulieu River Estuary, southern England was investigated. A geomorphological survey revealed that the creek bank geometry was characterized by the presence of cantilevers, a result of the protection provided by roots over the upper part of the bank. The saltmarsh deposits, consisting mainly of clay and organic matter, have a high resistance to flow-induced erosion. Short-term hydrographic deployments revealed that the tidal currents and waves recorded were insufficient to cause erosion of the bank surface. However, pin measurements over a 2-year period revealed that the tidal creeks within the saltmarsh did experience bank erosion, particularly below the cantilevers, in spite of this low-energy setting. Bank face erosion was therefore considered to be related to long-term processes. The bases of the cantilevers were found to be located at a precise level, in relation to the tides. Water level data over a 2-year period were examined against erosion measured below the cantilevers. The results suggest that the erosion on the bank faces, particularly below the cantilevers, is associated with the frequency of water level variations and long-term submergence/emergence cycles, which can decrease the bonds between the particles and enable erosion by low tidal and wind-wave currents within this low-energy environment. This mechanism is probably responsible for tidal creek enlargement via erosion of the bank face and subsequent bank failure, a process which acts over a long temporal scale (1-10 years).

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Creek enlargement in a low‐energy degrading saltmarsh in southern England

Collins

Thompson

2010

Earth Surf Processes Landf

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“…So, to a good first approximation. Mojid & Cho (2006), however, have recently explored some problems that arise when estimating the thickness of fully‐developed DDLs in clays.…”

Section: Theorymentioning

confidence: 99%

The effect of surface–solute interactions on the transport of solutes through porous materials

Rose¹,

Abbas²,

Adey³

2009

European J Soil Science

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We have investigated the effect of differences in surface charge, valency of ion, solute concentration, solution flux and physical structure on the leaching and uptake of individual ions from simple solutions flowing through porous materials. We studied the miscible displacement of solutions of four salts (KBr, K 2 SO 4 , CaBr 2 and CaSO 4 ) having different cation : anion ratios separately through three inert materials (ballotini, pumice and ceramic) and two sizes of a reactive material (sepiolite) over several ranges of concentration (c) and at many pore-water velocities (v) under steady vertical saturated flow. Breakthrough curves of individual effluent ions (K þ , Br À , Ca 2þ and SO 4 2À ) were analysed by CXTFIT 2.0 to optimize transport parameters (retardation factor, R; dispersion coefficient, K) assuming that transport was governed by the convective-dispersion equation. In the inert materials, R did not differ significantly from 1 irrespective of c. In sepiolite, R was < 1 for anions and > 1 for cations, and became more extreme as c decreased. R varied with the valency of the anions, as predicted by diffuse double layer theory, and with that of the cations by a simple charge balance. Freundlich isotherms, reconstructed from R values, described the sorption of the cations and exclusion of the anions. For the inert materials, K did not depend on the ion or c and increased monotonically with v. For sepiolite, K also increased with v and with small but non-significant differences between ions and concentrations. The K(v) functions were consistent with Passioura's theory of dispersion in aggregated media, and the transport was reversible as R and K values did not depend on whether the media were being leached or resalinized. The effective dispersion coefficient of an ion is K * ¼ K/R so, although K(v) appears to be unaffected by ion or concentration of solute in sepiolite, K * (v) will be affected. Thus, the controlling factor of these surface-solute interactions is R.

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“…This work has been supported by the European Social Fund within the project «Support for the implementation of doctoral studies at Riga Technical University» and National Research Program of Latvia 2010-2013 "Sustainable use of local resources particles have a significant impact on electrical conductivity. When a certain clay/water ratio is reached, conductivity decreases if clay content is decreased (Mojid and Cho, 2006). Sample F has the highest electrical conductivity, which can be another reason for lower apparent viscosity than samples A and C. Since samples B and D have much higher apparent viscosity and contain more clay minerals than sample E, the electrical conductivity of both these samples is mostly influenced by clay mineral particles, but for sample E -by the presence of soluble salts.…”

Section: Acknowledgementsmentioning

confidence: 97%

Rheological properties of Latvian illite clays

Dušenkova¹

2013

Acta Geodynamica Et Geomaterialia

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The influence of mineralogical composition, electrical conductivity and pH on the rheological properties of Latvian illite clays has been investigated. Samples from two deposits have been studied. The average plasticity index of samples from both Laza deposits is 23-25, but from Apriki -around 20. Based on these results, 2 samples with different plasticity indices from each borehole were chosen for further research. All suspensions exhibit yield-pseudoplastic behavior. Samples with the highest amount of clay minerals have the highest plasticity index and apparent viscosity. From 3 samples with similar amount of clay minerals and plasticity index one sample has higher pH and electrical conductivity and therefore exhibits lower viscosity.

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Estimating the fully developed diffuse double layer thickness from the bulk electrical conductivity in clay

Cited by 42 publications

References 17 publications

Creek enlargement in a low‐energy degrading saltmarsh in southern England

Creek enlargement in a low‐energy degrading saltmarsh in southern England

The effect of surface–solute interactions on the transport of solutes through porous materials

Rheological properties of Latvian illite clays

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