Effect of pH on Rheological Properties of Purified Sodium Bentonite Suspensions

Benna, Memia Zayani; Kbir‐Ariguib, N.; Magnin, Albert; Bergaya, F.

doi:10.1006/jcis.1999.6420

Cited by 186 publications

(90 citation statements)

References 24 publications

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“…Also, in the TEM images of MtFe 0 -1 to -6 the random arrangement of Mt and Fe nanoparticles is shown (the left panels of Figure 3aÀd), which may correspond to the partially disordered structure of Mt as revealed by the XRD analyses. This partially disordered structure of Mt could be described as a 'card-house' caused by edge-toface and/or edge-to-edge associations of clay particles (Benna et al, 1999). The 'card-house' structure was previously reported for Al-pillared interlayered clay by Pinnavaia et al (1984b) and characterized by a broad PSD and an absent or broadened (001) XRD reflection (Occelli et al, 1987).…”

Section: Discussionmentioning

confidence: 70%

“…The second unit is the particle arising from the short-range turbostratic stacking of layers along the c direction (Cadene et al, 2005). The third unit is the aggregate consisting of a group of particles associated with each other by different modes (Benna et al, 1999;RamosTejada et al, 2001). The arrangement of these units may provide Mt with interlayer, interparticle, and interaggregate pores of varied size and shape and, thus, make Mt versatile at accommodating various nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

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A Critical Textural Evolution Study of Zerovalent Iron/Montmorillonite Nanosized Heterostructures Under Various Iron Loadings

Fan

Yuan

Bergaya

et al. 2011

Clays and clay miner.

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Abstract-Heterostructures formed by nanoparticles hybridized with porous hosts are of great potential in many practical applications such as catalysis, adsorption, and environmental remediation, based on their intrinsic properties. The objectives of this study were to synthesize zerovalent iron nanoparticles/ montmorillonite heterostructures and to investigate their textural evolution under different Fe loadings. Iron nanoparticles were hybridized with montmorillonite by impregnation of montmorillonite by ferric ions followed by chemical reduction with sodium borohydride in solution. These hybridized Fe nanoparticles were well dispersed on the montmorillonite surface, size adjustable, and resistant to oxidation under the protection of native Fe-oxide shells. The textural evolution of these heterostructures under various Fe loadings was investigated using nitrogen physisorption, X-ray diffraction, electron microscopy, and elemental analyses. As the Fe loadings increased, the total pore and mesopore volumes were almost unchanged; the total, micropore, and external surface areas as well as the micropore volume decreased; and the average pore diameter increased. These textural changes could be attributed to the filling of the interparticle pores of montmorillonite by a variable amount of Fe nanoparticles. In addition, with increasing Fe loadings, the mesoporous character was enhanced for these heterostructures. These fundamental results are important in understanding the structure of these heterostructures as well as in developing some novel applications in related fields.

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Section: Discussionmentioning

confidence: 70%

Section: Introductionmentioning

confidence: 99%

A Critical Textural Evolution Study of Zerovalent Iron/Montmorillonite Nanosized Heterostructures Under Various Iron Loadings

Fan

Yuan

Bergaya

et al. 2011

Clays and clay miner.

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“…The results obtained by Benna et al [6] by using a Brookfield rheometer for silts Wyoming (WP) and Haidoudi (HP), show a great stability of the shear stress according to the pH for various rotational speeds, respectively in the ranges of pH between 4 and 9 for the first and between 5 and 9 for the second.…”

Section: Influence Of Phmentioning

confidence: 97%

“…Muds and silts are characterized by complex rheological behaviors (Ayadi [5], Benna et al [6], Coussot and Piau [8]): yield stress of flow, plasticity, thixotropy, rheofluidification. These rheological properties are controlled by the nature of clays, the physicochemical parameters (pH, ionic force, natural of ions, etc) and the presence of polymers (Delgado et al [11], Migniot [12], Pignon [13]).…”

Section: Introductionmentioning

confidence: 99%

Rheometry of silts of Fodda Wadi dam in relation to their transport and their valorization

Boudjenane¹,

Mekkaoui²,

Belhadri³

et al. 2007

WIT Transactions on Ecology and the Environment, Vol 104

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Silting of dams is an important economic concern in Algeria. This phenomenon considerably reduces the capacity of water reserves. The control of hydraulics and unsilting techniques, as well as the valorization of collected silts, pass by the rheometric comprehension of their behavior and the relationships to their physicochemical characteristics. For this purpose, five samples taken at selected places at the reserve of the Fodda Wadi dam will be studied. A granulometric study shows that we are in the presence of a mud whose particle size varies between 0,1 and 40µm and whose argillaceous fraction is about 50%. A study of the potential zeta of the silts shows a stability zone for pH between 6 and 10. Flow yield stress, which is a very important characteristic in unsilting of dams was studied. The effects of volumetric concentration, of pH and rest period on the flow yield stress, were studied. The yield stress increases considerably with the volumetric fraction. Scale laws according to concentration and sampling places are identified. A correlation is established between the evolution of the yield stress of flow and the evolution of the pH. Flow properties of the silts were studied on a wide range of shearing speed. An important preliminary work to control the disturbing effects (sedimentation, fracturing, etc) of rheometric characterization was carried out. Several geometries of measurements and visualizations of deformation fields were implemented. The influence of the concentration of the dry matter is presented.

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“…This critical stress that accompanies the transition between the solid and the viscous behaviors is related to the internal structure of the network of the material. The magnitude of the yield stress may depend on the concentration of the dissolved substances inducing the threshold and it may also vary with the pH of the solution (like bentonite [23]). A lot of behavior laws are available to describe such complex fluids.…”

Section: Objective Of the Studymentioning

confidence: 99%

Yield stress fluids method to determine the pore size distribution of a porous medium

Oukhlef

Champmartin

Ambari

2014

Journal of Non-Newtonian Fluid Mechanics

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. b s t r a c tIn this paper a new method is presented in order to determine the pore size distribution in a porous medium. This original technique uses the rheological properties of some non-Newtonian yield stress fluids flowing through the porous sample. This technique is based on the capillary bundle model (like the other classical methods) which, despite its apparent simplicity, is capable of properly characterizing the percolating pore size distribution. Then this distribution can be simply obtained from the measurement of the total flow rate as a function of the imposed pressure gradient. The present technique is successfully tested analytically and numerically for usual pore size distributions such as the Gaussian mono and multimodal distributions, using Bingham and Casson fluids. The technique can also be extended to any yield stress fluid and any kind of distribution.

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Effect of pH on Rheological Properties of Purified Sodium Bentonite Suspensions

Cited by 186 publications

References 24 publications

A Critical Textural Evolution Study of Zerovalent Iron/Montmorillonite Nanosized Heterostructures Under Various Iron Loadings

A Critical Textural Evolution Study of Zerovalent Iron/Montmorillonite Nanosized Heterostructures Under Various Iron Loadings

Rheometry of silts of Fodda Wadi dam in relation to their transport and their valorization

Yield stress fluids method to determine the pore size distribution of a porous medium

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