Organic matter reactivity

Dauwe, B., Middelburg, J. J., Herman, P. M. J., and Heip, C. H. R. (1999). Linking diagenetic alterantion of amino acids and bulk organic matter reactivity. Limnol. Oceanogr. 44, 1809-1814. 

Toth, D.J. and Lerman, A. Organic matter reactivity and sedimentation rates in the ocean. Amer. Jour. Sci. 277, 465-485 (1977). 

Similar trends in organic matter reactivity and isotopic composition are evident in sediments. For example, Wang and co-workers... 

Fig. 8. Steady-state model for the earth s surface geochemical system. The kiteraction of water with rocks ki the presence of photosynthesized organic matter contkiuously produces reactive material of high surface area. This process provides nutrient supply to the biosphere and, along with biota, forms the array of small particles (sods). Weatheriag imparts solutes to the water, and erosion brings particles kito surface waters and oceans.

Bromates represent a potential fire and explosion hazard if heated, subjected to shock, or acidified. They should not be allowed to contact reactive organic matter, including paper and wood. Industrial quantities are packed in fiber dmms with polyethylene liners or in metal dmms. Laboratory quantities are supphed in glass bottles. For shipment, a yellow oxidizer label is required under DOT regulations. 

Natural organic matter Nonpurgeable organic carbon Parts per million by volume Permeable reactive barriers Polyvinyl chloride... 

Carbonates, organic matter, Fe and Mn oxides, and clay minerals play important roles in controlling overall reactivity of trace elements in soils and sediments. This chapter addresses the interaction of trace elements with carbonates, organic matter, Fe and Mn oxides and clay minerals. Analytical techniques for trace element speciation in solid-phase and their distribution among various solid-phase components in arid and semi-arid soils are reviewed. Solubilities of trace elements in solid phases and their mineralogical characteristics in arid and semi-arid soils also are discussed. 

In summary, the removal of organic matter and Fe oxides significantly changes the physicochemical and surface chemical properties of soils. Thus, this pretreatment affects the overall reactivity of heavy metals in soils. The removal of organic matter and Fe oxides may either increase or decrease heavy metal adsorption. The mechanisms responsible for the changes in metal adsorption in soils with the removal of organic matter and Fe oxides include increases in pH, surface area, CEC and electrostatic attraction, decreases in the ZPC, shifts of positive zeta potentials toward... 

An important consideration in constructing certain types of geochemical models, especially those applied to environmental problems, is to account for the sorption of aqueous species onto sediment surfaces (e.g., Zhu and Anderson, 2002). Because of their large surface areas and high reactivities (e.g., Davis and Kent, 1990), many components of a sediment - especially clay minerals, zeolites, metal oxides and oxyhydroxides, and organic matter - can sorb considerable masses. 

Fig. 21.3. Transport of benzene within an aerobic aquifer, as depicted in Figure 21.2, calculated assuming the species not only biodegrades, but sorbs to organic matter in the aquifer. Benzene in the simulation sorbs with a distribution coefficient of 0.16 x 10-3 mol (g sediment)-1, equivalent to a retardation factor R of 2. Fine lines show non-reactive case.

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