Natural organic material

One example of a characterization application is the determination of a sample s age based on the kinetics for the decay of a radioactive isotope present in the sample. The most common example is carbon-14 dating, which is used to determine the age of natural organic materials. 

Tetrachloroethane [79-34-5] acetylene tetrachloride, CHCI2CHCI2, is a heavy, nonflammable Hquid with a sweetish odor. It is miscible with the chlorinated solvents and shows high solvency for a number of natural organic materials. It is also a solvent for sulfur and a number of inorganic compounds, eg, sodium sulfite. 

The Babylonians and Assyrians cemented stone slabs as well as bricks with bitumen (which is sometimes also referred to as asphalt), a mixture of a black or brown natural organic material with a pitchy luster and comminuted mineral. Bitumen is a thermoplastic solid material when heated above 50°C, it softens and becomes a thick, viscous liquid that reverts to a solid on cooling. It is composed of a natural mixture of hydrocarbons (organic substances composed of carbon, hydrogen, and oxygen) that occurs in natural... 

Over the centuries the natural organic materials that have best met these requirements are proteinaceous materials (egg, animal glue and casein or milk), polysaccharide gums... 

Fig. 4. Positive correlation between phenanthrene log Koc values and paraffinic carbon content (0-50 ppm) of the natural organic materials calculated from CP/MAS 13C NMR. Adopted from Salloum et al. (2002).

Low-volatility natural organic material such as polysaccharides and higher molecular weight proteins sometimes produced low results. In the Hannaker and Buchanan method [82] these problems are overcome by using a solution-phase oxidant and enclosing the system in a sealed tube. In this way all of the constituents are fully contained and exposed to oxidation and, moreover, oxidation of the organic matter to carbon dioxide is complete for the greater majority of compounds. 

Anaerobic conditions often develop in hydrocarbon-contaminated subsurface sites due to rapid aerobic biodegradation rates and limited supply of oxygen. In the absence of O, oxidized forms or natural organic materials, such as humic substances, are used by microorganisms as electron acceptors. Because many sites polluted by petroleum hydrocarbons are depleted of oxygen, alternative degradation pathways under anaerobic conditions tend to develop. Cervantes et al. (2001) tested the possibility of microbially mediated mineralization of toluene by quinones and humus as terminal electron acceptors. Anaerobic microbial oxidation of toluene to CO, coupled to humus respiration, was demonstrated by use of enriched anaerobic sediments (e.g., from the Amsterdam petroleum harbor). Natural humic acids and... 

The regenerative medicine consists of three components cell, nutrient, and scaffold. The combinatory usage of these components is important. For the scaffold manufacturing, bioactive natural organic materials originated from marine products are indispensable because the severe inflection problems such as bovine spongiform encephalopathy, avian and swine influenzas, and tooth-and-mouth disease in bovine, pig, and buffalo occur all over the world. 

In order to evaluate the ability of natural organic materials to sorb organic pollutants, it is useful to define an organic carbon normalized sorption coefficient ... 

Most natural organic materials which have strong odors, either agreeable or disagreeable, contain either mercaptans or alkyl sulfide. Various mercaptans have been found in crude oil, and the odor contributed by small quantities of these materials led to the name sour crude. 

Xu, H., Allard, B. and Grimvall, A. (1991) Effects of acidification and natural organic materials on the mobility of arsenic in the environment. Water, Air, and Soil Pollution, 57, 269-78. 

The natural organic matter suspended in the oceans at sites far from land consists of altered and linked biomolecules such as amino acids, sugars, and triglycerides that have been linked together. In large lakes and estuaries, the natural organic material in sediments and suspended sediments is derived from a mixture of the remains of terrestrial and planktonic organisms. 

Baldock, J. A., Oades, J. M., Nelson, P. N., Skene, T. M., Golchin, A., and Clark, R (1997). Assessing the extent of decomposition of natural organic materials using solid-state 13C NMR spectroscopy. Aust. J. Soil Rese. 35,1061-1083. 

Figure 2.2. Changes in particle size, C/N ratio, and chemical composition of organic matter in mineral soil with increasing extent of oxidative decomposition. Reprinted from Baldock, J. A., and Skjemstad, J. O. (2000). The role of soil mineral matrix in protecting natural organic materials against biological attack. Org. Geochem. 31, 697-710, with permission from Elsevier.

Wershaw, R., Burcar, P., and Goldberg, M. (1969). Interaction of pesticides with natural organic material. Environ. Sci. Technol. 3, 271-273. 

Kordel, W. (1997). Fate and effects of contaminants in soil as influenced by natural organic material—Status of information. Chemosphere 35,405 411. 

DeLapp, R. C., LeBoeuf, E. J., and Bell, K. D. (2004). Thermodynamic properties of several soil- and sediment-derived natural organic materials. Chemosphere 54(4), 527-539. 

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