Reactivity of mineral surfaces

Factors affecting the chemical reactivity of mineral surfaces... 

A variety of interrelated factors affect the chemical reactivity of mineral surfaces with respect to water and aqueous species, including (1) defect density, (2) cooperative effects among adsorbate molecules, (3) differences in intrinsic properties of different mineral surfaces, including different isoelectric points, (4) solution pH,... 

Hochella M. F. J. (1990) Atomic structure, microtopography, composition, and reactivity of mineral surfaces. In Mineral-Water Interface Geochemistry (eds. M. F. Hochella, Jr. and A. F. White). Mineralogical Society of America, Washington, DC, vol. 23, pp. 87-132. 

Natural Mineral Systems. Organic matter makes up only a minor mass fraction of most natural soils and of many sediments the bulk of the mass of these systems is mineral. On the other hand, all of the organic fraction may be available for participation in sorption reactions, whereas generally only the exposed surfaces of mineral fractions will participate. Nonetheless, if the reactivity of mineral surfaces is sufficient and the mass fraction of organic carbon is low, such surfaces may contribute significantly to overall sorption behavior. 

It is important to establish the origin and magnitude of the acidity (and hence, the charge) of mineral surfaces, because the reactivity of the surface is directly related to its acidity. Several microscopic-mechanistic models have been proposed to describe the acidity of hydroxyl groups on oxide surfaces most describe the surface in terms of amphoteric weak acid groups (14-17), but recently a monoprotic weak acid model for the surface was proposed (U3). The models differ primarily in their description of the EDL and the assumptions used to describe interfacial structure. "Intrinsic" acidity constants that are derived from these models can have substantially different values because of the different assumptions employed in each model for the structure of the EDL (5). Westall (Chapter 4) reviews several different amphoteric models which describe the acidity of oxide surfaces and compares the applicability of these models with the monoprotic weak acid model. The assumptions employed by each of the models to estimate values of thermodynamic constants are critically examined. 

Geochemistry of Mineral Surfaces and Factors Affecting Their Chemical Reactivity... 

Pan Ming Huang received his Ph.D. degree in soil science at the University of Wisconsin, Madison, in 1966. He is Professor Emeritus of Soil Science at the University of Saskatchewan, Saskatoon, Canada. His research work has significantly advanced the frontiers of knowledge on the formation chemistry and nature and surface reactivity of mineral colloids, organic matter, and organomineral complexes... 

The introductory chapter and the book itself is organized around three ideas What is the chemical structure What is the electronic structure What governs the surface chemical reactivity of minerals. 

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