Organic constituents

The organic constituents of coal, including both the maceral groups (liptinite, inertinite, and huminite/vitrinite) and the individual macerals in those groups (Chapter 4), are the basic elanents of many properties of coal. Vitrinite is the most common maceral group in many coals and it is the properties of the vitrinite in such coals, together with the variations in those properties with rank, that to a large extent determine the properties of the coal concerned. 

The determination of the properties of coal as a means of coal evaluation and with the goal of predicting behavior during utilization is well documented (Chapters 8 and 9). However, there is another area of coal characterization that has been at least equally well documented, but perhaps less well recognized as a means of evaluation, which involves studies of the molecular constituents of coal. 

In recent decades, there has been a strong tendency to characterize coals by structural analysis. Thus, coal can be characterized in terms of aromaticity (percentage of total carbon atoms existing in aromatic structures), number of aromatic atoms (or rings per cluster), number and types of functional groups, locations of oxygen atoms, location and types of heteroatoms. This has led to the postulation of speculative structure for coal which may (questionably) lead to a better understanding of utilization processes such as combustion. 

it can be argued (often successfully to a point but not ad nauseam) that an understanding of the chemical nature of coal constituents is, just like an understanding of the chemical and thermal behavior of coal (Chapters 13 and 14), a valuable part of projecting the successful use of coal for conversion and/or utilization processes such as combustion (Chapters 14 and 15), carbonization an briquetting (Chapters 16 and 17), liquefaction (Chapters 18 and 19), gasification (Chapters 20 and 21), or as a source of chemicals (Chapter 24). 

As an aside, but certainly worthy of note, the identification of many of the constituents of petroleum have been achieved as a result of the volatility of these constituents and subsequent application of methods such as gas-liquid chromatography and mass spectroscopy. But in the case of petroleum residua, which are the nonvolatile constitnents of petrolenm (boiling point 345°C [650°F]), identification of the individual constituents is much more difficult and heavy reliance has to be pnt on identification by molecular type (Speight, 2007). The same is essentially true for coal. 

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This method uses a short, packed column that generally produces a poor resolution of chromatographic peaks. The liquid-liquid extraction used to extract the trihalomethanes is nonselective. Besides the trihalomethanes, a wide range of nonpolar and polar organic constituents, such as benzene and... 

SW-846, is used to measure emissions of semivolatile principal organic constituents. Method 0010 is designed to determine destruction and removal efficiency (DRE) of POHCs from incineration systems. The method involves a modification of the EPA Method 5 sampling train and may be used to determine particulate emission rates from stationary sources. The method is applied to semivolatile compounds, including polychlorinated biphenyls (PCBs), chlorinated dibenzodioxins and dibenzofurans, polycyclic organic matter, and other semivolatile organic compounds. 

The rate of decomposition in unmanaged landfills, as measured by gas production, reaches a peak within the first 2 years and then slowly tapers off, continuing in many cases for periods up to 25 years or more. The total volume of the gases released during anaerobic decomposition can be estimated in a number of ways. If all the organic constituents in the wastes (with the exception of plastics, rubber, and leather) are represented with a generahzed formula of the form QH O N, the total volume of gas can be estimated by using Eq. (25-27) with the assumption of completed conversion to carbon dioxide and methane. 

Although most of the volatile components are released to the atmosphere, a small fraction is dissolved and/or carried away with the water in the soil matiix. Leached waters are carried with the water as it percolates through the underlying soil strata. Most of the organic constituents contained in the leachate receive additional treatment as they pass through the soil cohimn. Leached wastes can also be lost in surface rtinoff. 

Review of several alternative technologies to reduce the load of organic carbon on the activated carbon system produced the following conclusions. The organic constituents of the leachate (which accounts for about 60 percent of the combined wastewater volume but more than 80 percent of the total organic... 

O Troublesome organics Activated carbon filters are required where soluble organic constituents are present because many will pass straight through standard plants, e.g. pesticides, phenols, MTBE and so forth. 

The mixture was then allowed to warm to room temperature in a nitrogen atmosphere during which process the ammonia evaporated. The reaction mixture was then acidified with 1 N aqueous hydrochloric acid, and the organic constituents extracted with ethyl acetate. The ethyl acetateextracts were combined, washed with water and dried. Evaporation of the ethyl acetate under reduced pressure yielded 1.4 g of crude dl-trans-3-(r,r-dimethylheptyl)-6,6a, 7,8,10,10a -hexahydro-1 -hydroxy-6,6-dimethyl-9H-dibenzo(b/J] pyran-9-one. The... 

Robinson, T., The Organic Constituents of Higher Plants, Burgess Publishing Co., Minneapolis, Minn., 1963. 

Jang M, SR McDow (1997) Products of benz/a/anthracene photodegradation in the presence of known organic constituents of atmospheric aerosols. Environ Sci Technol 31 1046-1053. 

Valuable contributions were made by two Canadian agencies, particularly by the National Research Council Canada (NRCC) who, from about 1976, provided marine and marine biological CRMs certified for metals, metal species and organic constituents (Berman 1984 Willie 1997). More recently their Halifax laboratories have issued a highly respected range of CRMs for the determination of shellfish toxins. Another Canadian producer, the National Water Research Institute (NWRI) specialized in marine (water and sedimentary) CRMs, and from the late 1980 s their matrix materials certified also for organic compounds (Chau et al. 1979 Lee and Chau 1987). 

Schantz mm, Benner BA Jr, Chesler SN, Koster BJ, Hbhn KE, Stone SF, Kelly WR, Zeisler R, Wise SA (1990) Preparation and analysis of a marine sediment reference material for the determination of trace organic constituents. Fresenius J Anal Chem 338 501-514. 

Certified reference materials (CRMs) to validate measurements of organic constituents were introduced in the early 1980 s, more than a decade after the development of the first natural matrix CRMs for inorganic constituents. There are three types of CRMs to support measurements of organic constituents ... 

N 1ST Analytical Approach for the Certification of Organic Constituents in Natural Matrix SRMs... 

Schantz MM, Demiralp R, Greenberg RR, Hays MJ, Parris, RM, Porter BJ, Poster DL, Sander LC, Schiller SB, Sharpless KS, and Wise SA (1997a) Certification of a frozen mussel tissue standard reference material (SRM 1974a) for trace organic constituents. Fresenius J Anal Chem 358 431-440. 

Wise SA (1993) Standard reference materials for the determination of trace organic constituents in environmental samples. In Barcelo D, ed. Environmental Analysis Techniques, Applications and Quality Assurance, pp 403-446. Elsevier Science Publishers, Amsterdam, The Netherlands. Wise SA, and Schantz MM (1997) Standard reference materials for the determination of trace organic contaminants in environmental samples. In Clement R and Siu M, eds. Reference Materials for Environmental Analysis Making and Using Them, pp 143-186. Lewis Publishers, Boca Raton, FL. 

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