The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

Permien, T.; Lagaly, G.

doi:10.1346/ccmn.1995.0430210

Cited by 82 publications

(48 citation statements)

References 32 publications

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“…The rheological properties of suspensions of industrial clays such as bentonites and kaolins have been studied extensively in the past and it is well known that it is affected by particle size and shape, clay concentration, type of exchangeable cation, pH, electrolyte concentration and layer charge (Heath and Tadros, 1983;Brandenburg and Lagaly, 1988;Lagaly, 1989;Permien and Lagaly, 1995;Keren, 1988;. In contrast the rheological properties of palygorskite suspensions have been studied to a lesser degree.…”

Section: Introductionmentioning

confidence: 99%

Rheological Properties of Palygorskite-Smectite Suspensions From the Ventzia Basin, W. Macedonia, Greece

Christidis¹,

Katsiki²,

Pratikakis³

et al. 2017

geosociety

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Section: Introductionmentioning

confidence: 99%

Rheological Properties of Palygorskite-Smectite Suspensions From the Ventzia Basin, W. Macedonia, Greece

Christidis¹,

Katsiki²,

Pratikakis³

et al. 2017

geosociety

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“…Among possible alternative solutions is the strict environmental control of the temperature and relative humidity in the storage room. A treatment that would reduce the swelling capacity of the clay by exchanging the counterion (Na) for another with fewer hydration layers around the cation (Ca or Mg), in theory, should stabilize the clay structure by inducing aggregation of the clays and reduced swelling (Permien and Lagaly 1995). However, a practical method for accomplishing this without water-induced destruction of the stone has not been proposed.…”

Section: Discussionmentioning

confidence: 99%

“…However, a practical method for accomplishing this without water-induced destruction of the stone has not been proposed. Other possible conservation methods involve the application of surface active agents (surfactants) that have been reported to influence both the rheological and swelling properties of clays (van Olphen 1977;Permien and Lagaly 1995). By being fixed on the clay surface, these surface active agents influence the counterion distribution in the Stern and the diffuse ionic layers, resulting in a reduction of the swelling capacity of the clays.…”

Section: Discussionmentioning

confidence: 99%

The Role of Sepiolite-Palygorskite in the Decay of Ancient Egyptian Limestone Sculptures

Rodríguez-Navarro

Sebastián

Doehne

et al. 1998

Clays and clay miner.

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Abstract--An ancient Egyptian limestone sculpture was found to be undergoing major structural decay when stored in a museum environment. Mineralogical and petrographic analysis of the limestone showed a high proportion of clay (--10% by weight) that was concentrated along bedding planes. The clay fraction consisted mostly of sepiolite (>90%) and palygorskite (< 10%). Minor quantities (--< 1%) of soluble salts (NaCI and NaNO3) were also found. Wetting/drying with distilled water and relative humidity cycling resulted in the same delamination cracking damage as that observed in the museum environment. Thermomechanical analyses (TMA) confirmed that the damage was due to expansion (>4.5%) parallel to bedding planes when the limestone was immersed in water. The expansion due to swelling of the clays was directly observed at high magnification in an environmental scanning electron microscope (ESEM) when wetting/drying cycles were performed. X-ray diffraction (XRD) analysis showed that crystalline swelling of sepiolite occurred. This was determined by a shift of (110) reflection (from 12.07 to 12.20 A) and a decrease of (060) reflection (4.47 A, to 4.44 and 4.41 .~), when in contact with ethylene glycol (EG) and dimethyl sulfoxide (DMSO), respectively. Swelling also occurred due to hydration of the clay surfaces and to electrostatic forces between clay particles, which, it was assumed, was promoted by the presence of Na counterions in water solution. Possible treatments for the conservation of these artistic objects are proposed and discussed.

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“…Rand et al (1980) found no evidence for E-F coagulation in the pH range 4-11, in the presence of electrolyte at low concentration. The secondary electroviscous effect was the mechanism proposed by Rand et al (1980) and adopted by Permien and Lagaly (1994) for the minimum in yield stress and plastic viscosity; they suggested that the diffuse double layers around the particles affect their motion. At low electrolyte concentration in clay suspension, the extended diffuse double layer allows more freedom of movement under stress, whereas at higher electrolyte concentration the attractive forces between clay platelets dominate, and the yield stress and plastic viscosity increase again.…”

Section: Introductionmentioning

confidence: 96%

Rheology of Na-Rich Montmorillonite Suspension as Affected by Electrolyte Concentration and Shear Rate

Heller

Keren

2001

Clays and clay miner.

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Abstract--Rheological measurements were used to evaluate the particle-particle associations of Na-rich montmorillonite in suspensions, under various electrolyte concentrations. A 2% free electrolyte clay suspension showed pseudoplastic flow behavior and had a high apparent viscosity, attributed at low shear rates to the high volume fraction of the suspended clay platelets, the flexibility of the platelets, and the presence of edge-to-edge association. The breaking of edge-to-edge associations and the progressive orientation of the individual platelets in the direction of flow contribute to the reduction in viscosity with increasing shear rate.The compression of the diffuse double layer at a NaCI concentration of 10 mEq L -t contributes to the free movement of the individual platelets, even at low shear rates. The flow behavior changed from pseudoplastic to plastic at an NaCI concentration of 100 mEq L-L At this electrolyte concentration, face-to-face associations of specific junction points at certain areas of the planar surface are probably occurring.The apparent viscosity of the clay suspension for the two particle-size ranges (<2 and <0.02 p~m) at all shear rates converged to a minimum value of 4.5 mPa s at NaC1 concentrations of 10-20 mEq L-L On both sides of the minimum, the lower the shear rate, the greater the slope. The apparent viscosity of a 2% suspension of Na-rich montmorillonite <0.02 ~zm particles, however, was significantly greater than that observed for a suspension of <2 Ixm particles. This high apparent viscosity is attributed to the increase in edge surface area and the number of clay particles in a unit volume.We suggest that edge-to-edge association between Na-rich montmorillonite platelets prevails when the NaC1 concentration is below the electrolyte critical concentration, for which the apparent viscosity of the suspension is at its minimum value, whereas face-to-face association prevails at NaC1 concentrations above this critical value.

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The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

Cited by 82 publications

References 32 publications

Rheological Properties of Palygorskite-Smectite Suspensions From the Ventzia Basin, W. Macedonia, Greece

Rheological Properties of Palygorskite-Smectite Suspensions From the Ventzia Basin, W. Macedonia, Greece

The Role of Sepiolite-Palygorskite in the Decay of Ancient Egyptian Limestone Sculptures

Rheology of Na-Rich Montmorillonite Suspension as Affected by Electrolyte Concentration and Shear Rate

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