Soil Colloids

McBride M.B. Processes of heavy and transition metal sorption by soil mineral. In Interactions at the Soil Colloid-Soil Solution Interface, G.H. Bolt, M.F. De Boodt, M.H.B.Hayes, M.B. McBride, eds. NATO ASI Series (Series E Applied Sciences-Vol 190). Dordrecht, Netherlands Kluwer Academic Publishers, 1991. 

Several different types of species are illustrated in Figure 6.1. The potassium cation (K+) at the top of the figure is separated from the soil surface by water molecules and would thus be considered an outer-sphere species. The potassium cation near the bottom of the figure is directly connected to the soil particle by an ionic charge and is therefore an inner-sphere species. Above this is an inner-sphere phosphate directly bonded to a soil surface aluminum. Also shown are potassium cations attached (inner sphere) to colloidal clay (CC) and colloidal soil organic matter (COM). Each of these is a different species. 

Hayes, M. H. B. Mingelgrin, U. (1991). Interactions between small organic chemicals and soil colloidal constituents. In Interactions at the Soil Colloid — Soil Solution Interface, ed. G. H. Bolt, M. F. DeBoodt, M. H.B. Hayes, E.B.A. De Strooper, pp. 323-407. Dordrecht Kluwer Academic Publishers. 

Sanderson (1940) observed up to six-fold differences in the ability of soils to adsorb hydrocarbons in his laboratory. He also noted that the adsorptive characteristics of the colloidal soil systems would vary slowly with moisture content, time and season. Of particular significance was his observation that the adsorptive capacity for hydrocarbons on wet soil was only a small fraction of that for dry soil. A further complication is created by near-surface biological activity that creates wide variations in the content of carbon dioxide, nitrous oxide and other biological gases. Overcoming all these problems is probably impossible however, it will suffice if the gases are liberated in proportion to the amounts present so that the analytical results bear some relationship to one another, and allow identification of potentially prospective areas. 

Huang, P.M. 1975. Retention of arsenic by hydroxy-aluminum on surfaces of micaceous mineral colloids. Soil Sci. Soc. Am. Proc. 39 271-274. 

Figure 4.8. Time-dependence of phosphate sorption by a soil, attributed to the difference in chemisorption and precipitation kinetics. Total sorption is taken to be the sum of chemisorption and precipitation. (Adapted from S.E.A.T.M. Van der Zee and W. H. Van Riemsdijk. 1991. Model for the reaction kinetics of phosphate with oxides and soil. In G. H. Bolt et al. (eds.), Interactions at the Soil Colloid-Soil Solution Interface. Dordrecht Kluwer.)...

Swift, R. S. and R. G. McLaren. 1991. Micronutrient adsorption by soils and soil colloids. In Bolt et al., (eds.). Interactions at the Soil Colloid-Soil Solution Interface, pp. 257-292. 

In solntion, the A1(H20)6 ions neutralize the charge on the hydrophobic colloidal soil particles, leading to their precipitation from water. 

L.T. Zhuravlev mentions in historical order Lomonorov, 1723 for his work on properties of natural colloidal solutions, and coagulation and crystallization processes. Lovitz, 1785 Reiss, 1809 Borshchov, 1869 the famous Mendeleev, 1871 Veimam, 1904 author of one of the first textbooks on colloid chemistry Grdroitz, 1908, colloidal soils Zelinsky, proteins. 

McBride, M. B., and P. Baveye. 2002. Diffuse double-layer models, long-range forces, and ordering in clay colloids. Soil Science Society of America Journal 66, no. 4 1207. doi 10.2136/sssaj2002.1207. 

Pate, W. N., 1925. The influences of the amount and nature of the replaceable bases upon the heat of wetting of soils and soil colloids. Soil Sci. 20 329-375. 

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