The nature of organic matter

Symbols and abbreviations pl a, log of the acidic dissociation constant Exchange H , exchangeable H at typical environment conditions bold type, actual functional group. 

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Ittekot, V. 1988. Global trends in the nature of organic matter in river suspensions. Nature 332 436-438. 

Lyons, W.B., and Gaudette, H.E. (1979) Sulfate reduction and the nature of organic matter in estuarine sediments. Org. Geochem. 1, 151-155. 

The first case (Fig. 5) shows the effect of wastewater dilution leading to the same value of TOC than the treated sample. Obviously, the nature of organic matter is different as the treated effluent contains small oxygenated organic molecules, confirmed by the presence of nitrate (high Gaussian absorbance for short wavelengths see Chapter 5). From the environmental point of view, the impact of both effluents is obviously not similar. 

Metal mobility in soils is governed by interfacial processes, such as dissolution. The role of DOM in such processes will be determined by the nature of organic matter-surface associations. The surface complexation model provides a conceptual framework for estimating the contributions of specific DOM components, particularly LMW organic ligands, to the mobilization of metals in soils. With this framework, the effects of humic substances on mineral dissolution can be interpreted to provide some insight into hu-mate-surface interactions. 

In the removal of contaminating ions such as (PO or Fe " a precipitate such as Ca2(P0 2 Fe(OH)2, after oxidizing ferrous ion to ferric, is formed and the soHd is removed. The addition of surfactants is usually not essential (nor desirable) since most waters contain natural surfactants that would render the soflds sufficiently hydrophobic for flotation to occur. Such surfactants derive from the degradation of organic matter, and humic substances abundantly available in nature (30). 

HCIO4). Refluxed with benzene (6mL/g) in a flask fitted with a Dean and Stark trap until all the water was removed azeotropically (ca 4h). The soln was cooled and diluted with dry pentane (4mL/g of AgC104). The ppted AgC104 was filtered off and dried in a desiccator over P2O5 at 1mm for 24h [Radell, Connolly and Raymond J Am Chem Soc 83 3958 1961]. It has also been recrystallised from perchloric acid. [Caution due to EXPLOSIVE nature in the presence of organic matter.]... 

Most petroleum scientists believe that crude oil and natural gas formed over millions to tens of millions of years through the decomposition of organic matter buried by sediments. Generally, marine sediments have led to oil and gas, while freshwater... 

Our complex modern life style was made possible by the discovery and refining of fossil fuels, fuels that are the result of the decay of organic matter laid down millions of years ago. The natural gas that heats our homes, the gasoline that powers our automobiles, and the coal that provides much of our electrical power are fossil fuels. Vast reserves of petroleum, the source of liquid hydrocarbon fuels such as gasoline and coal, exist in many areas of the world. However, although large, these reserves are limited, and we are using them up at a much faster rate than they can be replaced. 

Naturally occurring oxaarenes based on polycyclic pyrans encompass a plethora of structures including the plant polyphenols such as anthocyanins and a-tocopherol (vitamin E). Halogenated dibenzo-p-dioxins and dibenzofurans are formed both as by-products during the manufacture of chlorophenols, and from the incineration of organic matter in the presence of inorganic halides. 

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