Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-22T18:57:43.174Z Has data issue: false hasContentIssue false

Bentonite and double hydroxides as emulsifying agents

Published online by Cambridge University Press:  09 July 2018

S. Abend
Affiliation:
Unilever Research Port Sunlight, Quarry Road East Bebington, Wirral L63 3JW, UK
G. Lagaly*
Affiliation:
University of Kiel, Institute of Inorganic Chemistry, D-24098 Kiel, Germany
*

Abstract

The use of solid-laden emulsions (Pickering emulsions) provides an interesting alternative to normal emulsions because the need for organic surfactants is removed or reduced. Combination of a bentonite with a layered double hydroxide represents an effective emulsifying system and provides high stability against coalescence. Solid contents as low as 0.1% (w/w, related to the total mass of the emulsion) are sufficient to prepare very stable O/W emulsions; the mass ratio of hydroxide/bentonite is not critical but should vary between 0.25 and 4 (corresponding to mass fractions of the hydroxide between χ = 0.2 and 0.8). With large hydroxide contents, stabilization is mainly caused by the envelope of hydroxide particles around the oil droplets. This shell provides a mechanical barrier against coalescence, typical of Pickering emulsions described so far. Addition of increasing amounts of bentonite provides an additional stabilization by building-up a threedimensional network consisting of both types of particles spanning the coherent phase. A high storage modulus at mass fractions of the hydroxide between 0.2 and 0.8 indicates high flexibility for the inorganic framework which is considered to be an important factor in the high stability of these emulsions.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abend, S. & Lagaly, G. (2000) Sol-gel transitions of sodium montmorillonite dispersions. Appl. Clay Sci. 16, 201227.Google Scholar
Abend, S., Bonnke, N., Gutschner, U. & Lagaly, G. (1998) Stabilization of emulsions by heterocoagulation of clay minerals and layered double hydroxides. Coll. Polym. Sci. 276: 730737.Google Scholar
Ashby, N.P. & Binks, B.P. (2000) Pickering emulsions stabilized by Laponite clay particles. Phys. Chem. Phys. 2, 56405646.Google Scholar
Bechhold, H., Dede, L. & Reiner, L. (1921) Dreiphasige Emulsionen. Kolloid-Z. 28, 619.Google Scholar
Binks, B.P. & Lumsdon, S.O. (2000) Effects of the oil type and aqueous phase composition on oil-water mixtures containing particles of intermediate hydro- phobicity. Phys. Chem. Chem. Phys. 2, 29592967.CrossRefGoogle Scholar
Chanamai, R. & McClements, D.J. (2000) Dependence of creaming and rheology of monodisperse oil-in-water emulsions on droplet size and concentration. Coll. Surf. A, 172, 7986.Google Scholar
Garfinkel-Shweky, D. & Yariv, S. (1997) The determination of surface basicity of the oxygen planes of expanding clay minerals by acridine orange. J. Coll. Interf. Sci. 188, 168175.Google Scholar
Giese, R.F., van Oss, C.J., Norries, J. & Costanzo, P.M. (1990) Surface energies of some smectite minerals. Proc. 9th Int. Clay Conf., Strasbourg 1989. Sci. Géol. Mém. 86, 3341.Google Scholar
Jennings, B.R. (1993) Size and thickness measurements of polydisperse clay samples. Clay Miner. 28, 485494.Google Scholar
Lagaly, G. (1994) Layer charge determination by alkylammonium ions. Pp. 146 in. Charge Characteristics of 2:1 Clay Minerals (Mermut, A., editor). CMS workshop lectures, Vol. 6. The Clay Minerals Society, Boulder, CO, USA.Google Scholar
Lagaly, G., Schulz, O. & Zimehl, R. (1997a) Dispersionen und Emulsionen. Eine Einführung in die Kolloidik feinverteilter Stoffe einschließlich der Tonminerale (mitein em histori schen Beitra güber Kol loidwissens chaf tler von Klaus Bene ke). Steinkopff Verlag Darmstadt. Pp. 233277.Google Scholar
Lagaly, G., Schulz, O. & Zimehl, R. (1997b) Dispersionen und Emulsionen. Eine Einführung in die Kolloidik feinverteilter Stoffe einschließlich der Tonminerale (mitein em histori schen Beitra güber Kol loidwissens chaf tler von Klaus Bene ke). Steinkopff Verlag Darmstadt. Pp. 279318.Google Scholar
Lagaly, G., Reese, M. & Abend, S. (1999a) Smectites as colloidal stabilizers of emulsions. I. Preparation and properties of emulsions with smectites and nonionic surfactants. Appl. Clay Sci. 14, 83103.Google Scholar
Lagaly, G., Reese, M. & Abend, S. (1999b) Smectites as colloidal stabilizers of emulsions. II. Rheological properties of smectite-laden emulsions. Appl. Clay Sci. 14, 279298.CrossRefGoogle Scholar
Lagaly, G., Mecking, O. & Penner, D. (2001) Colloidal magnesium aluminium hydroxide and heterocoagulation with a clay mineral. Coll. Polym. Sci. (in prep.).Google Scholar
Menon, V.B. & Wasan, D.T. (1986) Particle-fluid interactions with application to solid-stabilized emulsions. Part I. The effect of asphaltene adsorption. Coll. Surf. 19, 89105.Google Scholar
Meyn, M., Beneke, K. & Lagaly, G. (1990) Anionexchange reactions of layered double hydroxides. Inorg. Chem. 29, 52015207.Google Scholar
Mukerjee, L.N. & Srivastava, S.N. (1957) Finely divided solids as emulsifiers. Part III. Kolloid-Z. 150, 144148.Google Scholar
Neuhäusler, U., Abend, S., Jacobsen, C. & Lagaly, G. (1999) Soft X-ray spectromicroscopy on solidstabiliz ed emulsions. Coll. Polym. Sci. 277, 719726.Google Scholar
Penner, D. & Lagaly, G. (2000) Influence of organic and inorganic salts on the aggregation of montmorillonite dispersions. Clays Clay Miner. 48, 246255.Google Scholar
Pickering, S.U. (1907) Emulsions. J. Chem. Soc. 91, 20012021.Google Scholar
Pickering, S.U. (1910) Über Emulsionen. Z. Chem. Ind. Koll. (Kolloid-Z.) 7, 1116.CrossRefGoogle Scholar
Ramsden, W. (1904) Separation of solids in the surfacelayers of solutions and suspension (observations on surface-membranes, bubbles, emulsions, and mechanical coagulation). Proc. Roy. Soc. London, 72, 156164.Google Scholar
Schrader, M.E. & Yariv, S. (1990) Wettability of clay minerals. J. Coll. Interf. Sci. 136, 8594.CrossRefGoogle Scholar
Stul, M.S. & van Leemput, L. (1982) Particle-size distribution, cation exchange capacity and charge density of deferrated montmorillonites. Clay Miner. 17, 209215.Google Scholar
Tambe, D.E. & Sharma, M.M. (1993) Factors controlling the stability of colloid-stabilized emulsions. I. An experimental investigation. J. Coll. Interf. Sci. 157, 244253.Google Scholar
Thieme, J., Abend, S. & Lagaly, G. (1999) Aggregation in Pickering emulsions. Coll. Polym. Sci. 277, 257260.Google Scholar
Tributh, H. & Lagaly, G. (1986a) Aufbereitung und Identifizierung von Boden- und Lagerstättentonen. I. Aufbereitung der Proben im Labor. GITFachzeitschrift für das Laboratorium, 30, 524529.Google Scholar
Tributh, H. & Lagaly, G. (1986b) Aufbereitung und Identifizierung von Boden- und Lagerstättentonen. II. Korngrößenanal yse und Gewinnung von Tonsubfraktionen. GIT-Fachzeitschrift fü r das Laboratorium, 30, 771776.Google Scholar
Tsugita, A., Takemoto, S., Mori, K., Yoneya, T. & Otani, Y. (1983) Studies on O/W emulsions stabilized with insoluble montmorillonite-organic complexes. J. Coll. Interf. Sci. 95, 551560.Google Scholar
Van Oss, C.J. & Giese, R.F. (1995) The hydrophilicity and hydrophobicity of clay minerals. Clays Clay Miner. 43, 474477.CrossRefGoogle Scholar
Yan, N. & Masliyah, J.H. (1993) Solids-stabilized oil-inwater emulsions: scavenging of emulsion droplets by fresh oil addition. Coll. Surf. A, 75, 123132.Google Scholar
Yan, N. & Masliyah, J.H. (1994) Adsorption and desorption of clay particles at the oil-water interface. J. Coll. Interf. Sci. 168, 386392.Google Scholar
Yan, N. & Masliyah, J.H. (1995a) Characterization and demulsification of solids- stabilized oil-in-water emulsions. Part I. Partitioning of clay particles and preparatio n of emulsions. Coll. Surf. A, 96, 229242.Google Scholar
Yan, N. & Masliyah, J.H. (1995b) Characterization and demulsification of solids- stabilized oil-in-water emulsions. Part II. Demulsification by the addition of fresh oil. Coll. Surf. A, 96, 243252.Google Scholar
Yariv, S. (1992) The effect of tetrahedral substitution of Si by Al on the surface acidity of the oxygen plane of clay minerals. Int. Rev. Phys. Chem. 11, 345375.Google Scholar
Yariv, S. & Michaelian, K.H. (1997) Surface acidity of clay minerals. Industrial examples. Schriftenreihe angew. Geowiss. 1, 181190.Google Scholar