The discrete-ion effect in ionic double-layer theory

Levine, S.; Mingins, J.; Bell, Gail S.

doi:10.1016/0022-0728(67)80125-6

Cited by 105 publications

(53 citation statements)

References 88 publications

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“…Thus, the resultant adsorption free energy change is negative, and high-affinity adsorption of the surfactant moiety is facilitated. The use of localized charge density in above calculations (in place of the Braggs-William approximation of smeared out charge density) would, of course, lead to a larger value of electrostatic interaction (Levine et al, 1967). By the same token, counter-ion binding to surfactant head groups can significantly lower the repulsion between the head group and the surface and between head groups in the adsorbed layer (Hough and Rendall, 1983).…”

Section: Discussionmentioning

confidence: 99%

Use of Inorgano-Organo-Clays in the Removal of Priority Pollutants from Industrial Wastewaters: Structural Aspects

Srinivasan

Fogler

1990

Clays and clay miner.

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Abstract--Novel modified clay adsorbents were prepared by blocking cation-exchange sites of an expandable clay, such as montmorillonite, with polymeric or polyvalent inorganic ions and by using cationic surfactants as sources of surface organic carbon. Eleetrokinetic measurements demonstrated that the adsorbed polycations were essentially nonexchangeable. Adsorption and desorption experiments revealed that about 90% of the cationic surfactant was apparently irreversibly bound to the surface. Flocculation and peptization studies were performed to establish that the adsorbed surfactant moiety was oriented with its hydrocarbon tail towards the surface. Such a configuration of simultaneously adsorbed polycations and cationic surfactants was designated as an inorgano-organo-clay 0OC). As shown in an accompanying paper, these IOCs bind priority pollutants as strongly as granulated activated carbon.

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Section: Discussionmentioning

confidence: 99%

Use of Inorgano-Organo-Clays in the Removal of Priority Pollutants from Industrial Wastewaters: Structural Aspects

Srinivasan

Fogler

1990

Clays and clay miner.

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“…Of course, ions have different hydrated sizes so that the b-and d-planes are not strictly uniform layers. Our analysis does not include this detail (Levine et al 1967).…”

Section: Methodsmentioning

confidence: 99%

Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

et al. 2017

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SummaryLow-salinity waterflooding (LSW) is ineffective when reservoir rock is strongly water-wet or when crude oil is not asphaltenic. Success of LSW relies heavily on the ability of injected brine to alter surface chemistry of reservoir crude-oil brine/rock (COBR) interfaces. Implementation of LSW in carbonate reservoirs is especially challenging because of high reservoir-brine salinity and, more importantly, because of high reactivity of the rock minerals. Both features complicate understanding of the COBR surface chemistries pertinent to successful LSW. Here, we tackle the complex physicochemical processes in chemically active carbonates flooded with diluted brine that is saturated with atmospheric carbon dioxide (CO 2 ) and possibly supplemented with additional ionic species, such as sulfates or phosphates.When waterflooding carbonate reservoirs, rock equilibrates with the injected brine over short distances. Injected-brine ion speciation is shifted substantially in the presence of reactive carbonate rock. Our new calculations demonstrate that rock-equilibrated aqueous pH is slightly alkaline quite independent of injected-brine pH. We establish, for the first time, that CO 2 content of a carbonate reservoir, originating from CO 2 -rich crude oil and gas, plays a dominant role in setting aqueous pH and rock-surface speciation.A simple ion-complexing model predicts the calcite-surface charge as a function of composition of reservoir brine. The surface charge of calcite may be positive or negative, depending on speciation of reservoir brine in contact with the calcite. There is no single point of zero charge; all dissolved aqueous species are charge determining. Rock-equilibrated aqueous composition controls the calcitesurface ion-exchange behavior, not the injected-brine composition. At high ionic strength, the electrical double layer collapses and is no longer diffuse. All surface charges are located directly in the inner and outer Helmholtz planes.Our evaluation of calcite bulk and surface equilibria draws several important inferences about the proposed LSW oil-recovery mechanisms. Diffuse double-layer expansion (DLE) is impossible for brine ionic strength greater than 0.1 molar. Because of rapid rock/brine equilibration, the dissolution mechanism for releasing adhered oil is eliminated. Also, fines mobilization and concomitant oil release cannot occur because there are few loose fines and clays in a majority of carbonates. LSW cannot be a low-interfacial-tension alkaline flood because carbonate dissolution exhausts all injected base near the wellbore and lowers pH to that set by the rock and by formation CO 2 . In spite of diffuse double-layer collapse in carbonate reservoirs, surface ion-exchange oil release remains feasible, but unproved.Introduction LSW refers to improved oil recovery achieved by waterflooding a reservoir with brine of lower salinity than that of the field brine. The process is alluring because of simplicity, favorable economics, and large potential. In some applications, seawater is inj...

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“…The reason for this arises from the fact that the model considers the (1) thickness of an order of magnitude as the molecular size, while it will be shown later, that the surface inhomogenous region is much thicker than this. After the Helmholtz description, the next model proposed was by Gouy & Chapman (15)(16)(17)(18)(19)(20). In the Gouy-Chapman model the structure of the double layer is suggested to be determined by the intensity of the electric field associated with the adsorbed layer of film forming molecules, which will attract the oppositely charged ions from the bulk phase as close to the interface as possible through electrostatic forces.…”

Section: W635mentioning

confidence: 99%

“…As well as a modified discrete (net) charge model is given in the following which was found to give a satisfactory analysis about the state of electrostatic charge image forces. Gouy-Chapman model: According to this model [15,17,18,19,20] satisfactory analyses of adsorbed and spread monolayers of simple charged amphiphiles for example n-alkyl sulfates etc. [15,17,18,19,20].…”

Section: Equation Of State For Charged Monolayersmentioning

confidence: 99%

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Equation of state for monomolecular films of melittin at air-water interface

Birdi

Gevod²,

Ksenzhek³

et al. 1983

Colloid & Polymer Sci

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Abstract:The spread monolayers of proteins at the air-water interface have been reported to be very useful model membrane systems. The charged protein monolayers have been analyzed by using the Gouy-Chapman (-Stern) models. These models gave satisfactory analyses of "non-membrane" proteins, but could not be used for the data of charged melittin monolayers ("membrane protein"). In order to describe these data, a new discrete (net) charge model is developed, and the equation of state for these two-dimensional films is discussed herein. This study shows, for the first time, that discrete (net) charges are present in charged melittin (a peptide with 26 amino acids) monolyers. The measured surface pressure,/7, and surface potential, A~p, are analyzed with the help of the discrete charge model.

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The discrete-ion effect in ionic double-layer theory

Cited by 105 publications

References 88 publications

Use of Inorgano-Organo-Clays in the Removal of Priority Pollutants from Industrial Wastewaters: Structural Aspects

Use of Inorgano-Organo-Clays in the Removal of Priority Pollutants from Industrial Wastewaters: Structural Aspects

Bulk and Surface Aqueous Speciation of Calcite: Implications for Low-Salinity Waterflooding of Carbonate Reservoirs

Equation of state for monomolecular films of melittin at air-water interface

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