Chapter 8 - Colloid Clay Science

https://doi.org/10.1016/B978-0-08-098258-8.00010-9Get rights and content

Abstract

The knowledge of the properties of colloidal dispersions is fundamental for designing and optimizing the usage of clays and clay minerals. The colloidal behaviour of these dispersions is very complex due to the anisometric (and often irregular) particle shape, the anisometric and pH-dependent charge distribution, the variable particle dimensions as a consequence of swelling, delamination and exfoliation, and the ion-exchange properties. Therefore, this chapter gives information on the structure, charge distribution, structure of the hydrates, diffuse ionic layer, and the interactions between the colloidal clay mineral particles (electrostatic, van der Waals, ion correlation, steric stabilization). A large section refers to the coagulation of clay mineral dispersions by salts, the influence of organic compounds, and the destabilization (flocculation by bridging or charge neutralization) or stabilization by polymers (by recharging or steric stabilization). In a further section is described the aggregation of clay mineral particles leading to different types of sediments (decisively determining sealing, plastering, stirring, filtration processes, plasticity) or resulting in gel formation, often with thixotropic properties. Also mentioned is the preparation of colloidal metal (hydr)oxides and sulphides within the network of clay mineral particles or even between the clay mineral layers.

Section snippets

Particle and Aggregate Structure

Clay mineral particles, in particular those of smectites, are never crystals in the strict sense (Brindley and Brown, 1980, Moore and Reynolds, 1997, Plançon, 2001). Many crystallographers are dismayed at the particles clay scientists often call ‘crystals’. In fact, a smectite ‘crystal’ is more equivalent to an assemblage of silicate layers than to a true crystal (Fig. 8.1). Montmorillonite (Mt) particles seen in the electron microscope never have the regular shape of real crystals but look

Hydrates of 2:1 Clay Minerals

The 2:1 clay minerals form hydrates with one, two, three or four pseudo-layers of water molecules between the silicate layers. The state of hydration changes with the water vapour pressure, with the water content, and, in salt solutions, with the type and concentration of salts, and is dependent on the layer charge and the interlayer cation density. Typical basal spacings are 1.18–1.24 nm (water pseudo-monolayer), 1.45–1.55 nm (water pseudo-bilayer), and 1.9–2.0 nm (four water pseudo-layers). The

Fractionation of Clay Dispersions

Clay minerals with a certain degree of purity can be separated from raw clay samples by sedimentation techniques. The first step consists of removal of iron oxides and organic materials. These materials not only affect the properties of colloidal dispersions but also prevent optimal peptization of clay particles and successful fractionation by sedimentation. To prepare colloidal dispersions, it is important to remove carbonates and silica (see Chapter 7.1). Carbonates can release calcium or

Coagulation by Inorganic Salts

Since the colloidal state of dispersed clay minerals is decisive in many practical applications, the coagulation of kaolinite and Mt dispersions was investigated for many decades (Jenny and Reitemeier, 1935, Kahn, 1958). Unlike other colloidal dispersions, well-dispersed clay minerals (kaolinites, smectites, illites, palygorskite) in the sodium form may be coagulated by very low concentrations of inorganic salts. The critical coagulation concentration, cK, of sodium chloride varies between 3

Flocculation by Bridging and Charge Neutralization

Macromolecules can flocculate colloidal dispersions by two different mechanisms: bridging between the particles and charge neutralization (Fig. 8.17) (Chaplain et al., 1995, Lagaly et al., 1997, Theng, 2012).

Bridging requires that the macromolecules can attach to the surface of two approaching particles and that the bridging part of the macromolecules is compatible with the solvent (the solvent has to be a better-than-theta solvent). In aqueous dispersions, a certain low salt concentration is

Modes of Aggregation

The most well-known mode of aggregation is the house-of-cards model, where the clay mineral particles are held together by edge/face contacts (Fig. 8.24A) (Hofmann, 1961, Hofmann, 1962, Hofmann, 1964). This type of network forms only when the edges are positively charged, or in a slightly alkaline medium above the critical salt concentration. Formation of edge/face contacts below pH  6 is due to hetero-coagulation between the positive edges and the negative faces of the particles or silicate

Clay Mineral Hybrid Films

The formation and properties of hybrid films of clay minerals bridge clay colloid science and materials science. If appropriate conditions are selected, clay mineral platelets settle to form a sediment where the platelets preferentially adopt a parallel orientation (see Section 8.6.3). Drying produces oriented films that are often used in spectroscopic investigations and X-ray diffraction and are considered for possible new applications of clay minerals (Fitch et al., 1998, Fendler, 2001). Such

Formation of Nanoparticles in Clay Minerals

Clay mineral particles provide confined volumes of nano-sized dimensions for the formation of colloidal particles. The confined space between particles or layers of clay minerals limits the particle growth (Fig. 8.44).

Formation of colloidal metal particles was observed decades ago during the oxidation of octahedral Fe2 + ions in micas by interlayer silver cations. The silver atoms aggregated to Ag0 particles outside the interlayer spaces (Sayin et al., 1979). Giannelis et al. (1988) described

References (378)

  • M. Borkovec et al.

    Surface area and size distributions of soil particles

    Colloids Surf. A

    (1993)
  • J.Y. Bottero et al.

    Mechanism of formation of aluminum trihydroxide from Keggin Al13 polymers

    J. Colloid Interface Sci.

    (1987)
  • J.Y. Bottero et al.

    Adsorption of non-ionic polyacrylate on sodium montmorillonite

    J. Colloid Interface Sci.

    (1988)
  • U. Brandenburg et al.

    Rheological properties of sodium montmorillonite dispersions

    Appl. Clay Sci.

    (1988)
  • C. Breen

    The characterisation and use of poly cation-exchanged bentonites

    Appl. Clay Sci.

    (1999)
  • I. Dékány et al.

    Cadmium ion adsorption controls the growth of CdS nanoparticles on layered montmorillonite and calumite surfaces

    Appl. Clay Sci.

    (1999)
  • D. Dollimore et al.

    The dependence of the flocculation behavior of China clay-polyacrylamide suspensions on the suspension pH

    J. Colloid Interface Sci.

    (1973)
  • J. Dousma et al.

    Hydrolysis-precipitation studies of iron solutions I. Model for hydrolysis and precipitation from Fe(III) nitrate solutions

    J. Colloid Interface Sci.

    (1976)
  • J.F. Dufrêche et al.

    Models for electrokinetic phenomena in montmorillonite

    Colloids Surf. A

    (2001)
  • G. Durand-Piana et al.

    Flocculation and adsorption properties of cationic polyelectrolytes toward Na-montmorillonite dilute suspensions

    J. Colloid Interface Sci.

    (1987)
  • A.P. Ferris et al.

    The exchange capacities of kaolinite and the preparation of homoionic clays

    J. Colloid Interface Sci.

    (1975)
  • G. Frens et al.

    Repeptization and the theory of electrocratic colloids

    J. Colloid Interface Sci.

    (1972)
  • E. Frey et al.

    Selective coagulation and mixed-layer formation from sodium smectite solutions

  • E. Frey et al.

    Selective coagulation in mixed colloidal suspensions

    J. Colloid Interface Sci.

    (1979)
  • J.J. Fripiat et al.

    Thermodynamic and microdynamic behavior of water in clay suspensions and gels

    J. Colloid Interface Sci.

    (1982)
  • J. Ganor et al.

    Surface protonation data of kaolinite-reevaluation based on dissolution experiments

    J. Colloid Interface Sci.

    (2003)
  • D. Garfinkel-Shweky et al.

    The determination of surface basicity of the oxygen planes of expanding clay minerals by acridine orange

    J. Colloid Interface Sci.

    (1997)
  • B. Gherardi et al.

    Sol/gel phase diagrams of industrial organo-bentones in organic media

    Appl. Clay Sci.

    (1996)
  • R.F. Giese et al.

    Water molecule positions, orientations, and motions in the dihydrates of Mg and Na vermiculites

    J. Colloid Interface Sci.

    (1979)
  • S. Goldberg

    Use of surface complexation models in soil chemical systems

    Adv. Agron.

    (1992)
  • D. Gournis et al.

    Catalytic synthesis of carbon nanotubes on clay minerals

    Carbon

    (2002)
  • W.T. Granquist et al.

    The gelation of hydrocarbons by montmorillonite organic complexes

    J. Colloid Sci.

    (1963)
  • S. Akari et al.

    Imaging of single polyethyleneimine polymers adsorbed on negatively charged latex spheres by chemical force microscopy

    Langmuir

    (1996)
  • T. Allen

    Particle Size Measurement

    (1997)
  • N. Alperovitch et al.

    Effect of clay mineralogy and aluminum and iron oxides on the hydraulic conductivity of clay–sand mixtures

    Clays Clay Miner

    (1985)
  • A.H.M. Andreasen

    Einige Beiträge zur Erörterung der Feinheitsanalyse und ihrer Resultate

    Arch Pflanzenbau

    (1931)
  • A.H.M. Andreasen

    Beispiele der Verwendung der Pipettenmethode bei der Feinheitsanalyse unter besonderer Berücksichtigung von Mineralfarben

    Angew. Chem.

    (1935)
  • M. Arias et al.

    Effects of iron and aluminium oxides on the colloidal and surface properties of kaolin

    Clays Clay Miner

    (1995)
  • A. Atterberg

    Die Plastizität der Tone

    Internationale Mitteilungen Bodenkunde I

    (1911)
  • D.C. Bain et al.

    Chemical analysis

  • L.M. Barclay et al.

    Measurement of forces between colloidal particles

    Special Discuss. Faraday Soc.

    (1970)
  • I. Barshad

    Preparation of H saturated montmorillonite

    Soil Sci.

    (1969)
  • J. Ben Brahim et al.

    Methode diffractometrique de characterisation des etats d'hydratation des smectites stabilité relative des couches eau inserées

    Clay Miner.

    (1986)
  • M. Benna et al.

    Card-house microstructure of purified sodium montmorillonite gels evidenced by filtration properties at different pH

    Prog. Colloid Polym. Sci.

    (2001)
  • R. Bergman et al.

    Dielectric study of supercooled 2D water in a vermiculite clay

    J. Chem. Phys.

    (2000)
  • R. Bertram et al.

    Zur Art der Al-Kationen in hochbasischen, hochkonzentrierten Aluminiumchloridlösungen

    Z. Anorganische Allgemeine Chem.

    (1985)
  • G. Besson et al.

    Order and disorder relations in the distribution of the substitutions in smectites, illites and vermiculites

    Clays Clay Miner.

    (1974)
  • J. Beyer et al.

    An extended revision of the interlayer structures of one- and two-layer hydrates of Na-vermiculite

    Clay Miner.

    (2002)
  • A.V. Blackmore

    Aggregation of clay by the products of iron(III) hydrolysis

    Aust. J. Soil Res.

    (1973)
  • M.R. Böhmer et al.

    Adsorption of ionic surfactants on variable-charge surfaces. 1. Charge effects and structure of the adsorbed layer

    Langmuir

    (1992)
  • Cited by (79)

    • Tuning the rheological properties of kaolin suspensions using biopolymers

      2022, Colloids and Surfaces A: Physicochemical and Engineering Aspects
    View all citing articles on Scopus
    View full text