Colloid clays

H. van OIphen,M / Introduction to Clay Colloid Chemisty, 2nd ed., John Wiley Sons, Inc., New York, 1977. 

Van Olphen H. An Introduction to Clay Colloid Chemistry For Clay Technologist, Geologist and Soil Scientist. Malabar, FL Krieger 1991. 

Van Olphen, H. (1977), An Introduction to Clay Colloid Chemistry, 2nd Ed., John Wiley and Sons, New York. 

It is reasonable to assume that clay colloids exhibit a similar surface chemistry as clay which is sorbed, bonded, or precipitated in the stationary solid phase. Mineral colloids may be formed when precipitation or dissolution generate particles which are resistant to settling. These particles maybe formed by any number of conditions whereby the solubility of a particular solute is exceeded or a stable solid is disrupted mechanically [21,24]. 

In various kinds of industrial production, materials need to be treated with charged colloidal particles. In such systems, the value of the zeta-potential analyses are needed to control production. For example, in paper, adhesive, and synthetic plastics, colloidal clay can be used as filler. In oil drilling, clay colloidal suspensions are used. The zeta potential is controlled so as to avoid clogging the pumping process in the oil well. It has been found that, for instance, the viscosity of a clay suspension shows a minimum when the zeta potential is changed (with the help of pH from 1 to 7) from 15 to 35 mV. Similar observations have been reported in coal slurry viscosity. The viscosity was controlled by the zeta potential. 

Missana, T. Adell, A. 2000. On the applicability of DLVO theory to the prediction of clay colloids stability. Journal of Colloid and Interface... 

Van Olphen H (1977) An introduction to clay colloid chemistry, 2nd Edn. Wiley Interscience,... 

Clay Minerals and Clay Colloids. The literature on clays and clay colloids is expansive, but there remains a degree of uncertainty in many areas of their study due to their inherent heterogeneity. Descriptions of the structures and properties of clay minerals can be found in Grim (1968), Brindley and Brown (1980), Newman and Brown (1987), Sposito et al. (1999), and Giese and van Oss (2002). 

Clay minerals and clay colloids are the products of the advanced weathering of primary silicates. They are comprised mainly of silica and alumina, often with appreciable amounts of alkali and alkaline earth metals and iron. Most also have varying amounts of water bound to their surfaces and can take on a variety of different chemical and physical properties depending on the amount of water adsorbed. They have the ability to exchange or bind cations and anions and are capable of complex formation with a wide variety of organic molecules. 

Figure 3.2. Structural units of clay minerals and clay colloids (a) Octahedral sheet, (b) tetrahedral sheet. Reprinted with permission from Grim, R. E. (1968). Clay Mineralogy, 2nd edition, McGraw-Hill, New York.

Rothe, J., Denecke, M. A., and Dardenne, K. (2000). Soft X-ray spectromicroscopy investigation of the interaction of aquatic humic acid and clay colloids. J. Coll. Interface Sci. 231, 91-97. 

Triazine herbicide soil activity, movement, and residues depend primarily on content of organic matter, and to a lesser extent, clay colloids (Nearpass 1965 Day et al, 1968 Weber et al, 1969). Soils that are low in organic matter or clay usually require lower herbicide rates, but result in more potential phytotoxicity (Lange et al, 1969a). Simazine (4.0kg/ ha) or diuron (5.0kg/ha) gave season-long weed control in soils of the Northwest (Hogue and Neilsen, 1987). 

Weber, J.B. (1970b.) Mechanisms of adsorption of s-triazines by clay colloids and factors affecting plant availability. In F.A. Gunther and J.D. Gunther, eds., The Triazine Herbicides. Residue Rev., 32. New York Springer-Verlag, pp. 93-130. 

Actinide and Technetium Sorption on Iron-Silicate and Dispersed Clay Colloids... 

Colloidal dispersions suspensions and aggregates Viscosity and transient electric birefringence study of clay colloidal aggregation. Physical Review E 65, 21407-21500... 

Clay colloids provide a good example of the kinds of structures that can be formed upon flocculation. The association of plate-like clay particles is complicated by the fact that minerals such as montmorillonite, illite, and kaolinite can exhibit different surface charges at different particle surfaces. 

Colloid science books available up to now have been either principally theoretical (such as the classic and standard colloid chemistry texts), or they focus on specific types of colloidal dispersion (like van Olphen s classic book on clay colloid chemistry [1]), or on applications of a specific type of dispersion in a specific industry, like the author s petroleum industry series ... 

---