Surface mineral, abiotic organic

Abiotic organic reactions, such as hydrolysis, elimination, substitution, redox, and polymerization reactions, can be influenced by surfaces of clay and primary minerals, and of metal oxides. This influence is due to adsorption of the reactants to surface Lewis and Br nsted sites. Temperature and moisture content are the most important environmental variables. Under ambient environmental temperatures, some reactions are extremely slow. However, even extremely slow transformation reactions may be important from environmental and geochemical viewpoints. 

Abiotic organic reactions that may be influenced by mineral surfaces include hydrolysis, elimination, substitution, redox, and polymerization. The effect of the surface may be either to promote (increase the rate of) or to inhibit (decrease the rate of) reactions that may occur in homogeneous solution. In addition, mineral surfaces may promote reactions that do not occur in homogenous solution by selectively concentrating molecules at the mineral surface... 

Voudrias, E. A. Reinhard, M. (1986). Abiotic organic reactions at mineral surfaces. In Geochemical Processes at Mineral Surfaces, ed. J.A. Davis K. F. Hayes, pp. 462-86. Washington, DC American Chemical Society. 

Voudrias, E.A., and M. Reinhard. 1986. Abiotic organic reactions at surfaces of minerals, p. 462-486. In J.A. Davis and K.F. Hayes (ed.) Geochemical processes at mineral surfaces. ACS Symposium Series 323. ACS, Washington, DC. 

Reduction of nitro aromatic compounds often appears to be a two-step process, in which a mediator is required for facile transfer of electrons from a bulk reductant to the contaminant. A well documented example is the coupling of organic matter oxidation by iron reducing bacteria to "abiotic" nitro reduction by biogenic Fe(II) that is adsorbed to mineral surfaces in a column containing aquifer material (36, 39, 76). 

Environmental organic matter is a composite of humic and nonhumic substances, which is formed through operation and interactions of various biotic and abiotic processes. Humic substances are formed through both selected preservation (residue) and catalytic synthesis mechanisms. Both enzymatic and mineral catalyses contribute to the formation of humic substances in the environment. The relative importance of these catalytic reactions would depend on vegetation, microbial population and activity, enzymatic activity, mineralogical composition and surface chemistry of environmental particles, management practices, and environmental conditions. Selective preservation pathways would play a more important role in humification processes in poorly drained soils and lake sediments, compared with more aerated environmental conditions. 

Birkel, U., Gerold, G., and Niemeyer, J. (2002). Abiotic reactions of organics on clay mineral surfaces. In Soil Mineral-Organic Matter-Microorganism Interactions and Ecosystem Health Dynamics, Mobility and Transformation of Pollutants and Nutrients. Violante, A., Huang, P. M., Bollag, J.-M. and Gianfreda, L., eds., Elsevier Science B.V., Amsterdam,The Netherlands, pp. 437 447. 

Marine carbonate minerals have both biotic (dominant) and abiotic (minor) sources. Their formation is often controlled by kinetic factors or biomediated processes in organisms. Surface seawater is most highly supersaturated (the ion activity product (lAP) is much greater than the solubility product) with respect to dolomite ( 50X), followed by pure calcite ( 6 X), then by aragonite ( 4x). It may be close to... 

DOC transport through the soil and its concentration leaving a soil profile depends on abiotic sorption and desorption reactions with mineral surfaces. The tendency for organics to be strongly sorbed to soil particles through a variety of bonds can explain the order of magnitude drop in DOC fluxes in subsurface horizons (Neff and Asner, 2001 Ugolini et aL, 1977). For example, at the Harvard Forest, Massachusetts, Currie et al. 

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