Organic fractions, mass balance

Reactive Organic Chemical Mass Balance (Friedlander). In the original formulation of the CMB receptor model (1) it was recognized that the fractional amounts of various chemical species emitted by a source are not necessarily conserved during the transport of the species to the receptor site. This could occur through both physical (differential dispersion or deposition) or chemical (removal due to atmospheric reactions) processes. This possibility was acknowledged by writing the CMB equations in the form... 

The actual volume of each phase in element AV is that of the total volume of the element, multiplied by the respective fractional phase holdup. Hence considering the direction of solute transfer to occur from the aqueous or feed phase into the organic or solvent phase, the mass balance equations become ... 

In the manufacture of aniline from nitrobenzene the reactor products are condensed and separated into an aqueous and organic phases in a decanter. The organic phase is fed to a striping column to recover the aniline. Aniline and water form an azeotrope, composition 0.96 mol fraction aniline. For the feed composition given below, make a mass balance round the column and determine the stream compositions and flow-rates. Take as the basis for the balance 100 kg/h feed and a 99.9 percentage recovery of the aniline in the overhead product. Assume that the nitrobenzene leaves with the water stream from the base of the column. 

Table 1 presents the results of fractionations of the DOM. The result of mass balance calculation of the DOC system shows that more than 55 % of the total DOC was retained by XAD-8 resin column, involving the portions of Ho A and HbN/B, and DOC concentrations of the portion eluted by blackwashing (HoA) accounted for 47.4 % of total DOC, as compared with 26.25 % hydrophilic acids (HiA) of the total DOC. More than 11% of the total DOC passed through two resin columns, indicating that small molecular weight polar components were not absorbed onto by XAD-8 and XAD-4. The fractionation did cause potential loss of organic matter by permanent adsorption onto resin s polymers, which were 8.34 % for the XAD-8 resin and 6.41 % for the XAD-4 resin, respectively. 

The chemical composition of particles collected in the museums was also compared to that outdoors using a mass balance model. The results indicated that there were significant indoor sources of fine particle organics and that this source(s) was a significant fraction of the total indoor fine particle organic concentration (Ligocki et al., 1993). A similar conclusion was reached by Naik et al. (1991) in measurements made in a telephone... 

The inherent chemical complexity of DOM presents many challenges to understanding the role of DOM in C and N cycling and other processes in aquatic ecosystems. The measurement of trace organic moieties in major fractions of DOM, such as fulvic acids, can provide valuable data for understanding sources and biogeochemical pathways. In field studies, multiple lines of evidence can be critical for definitive interpretation of results. The tracer approaches outlined in this chapter should be used in conjunction with mass balance and flux measurements, for example. 

The parameters of the pyrolysis experiments are shown in Table 24.4. In the experiments, the pyrolysis temperature was 450°C which was found in previous experiment with pure PMMA to be the optimal temperature. Total mass balances are calculated to the organic content even for the filled PMMA to allow a comparison. The losses (1-2%) calculated to 100% were determined on all product fractions proportionately. The following results should be noted. 

The isotopic fractionation in carbonates mirrors the relative amount of organic carbon buried. It is generally assumed that the source carbon, from vulcanism (the so-called mantle carbon) has an isotopic value of approximately 5%c. As mass balance must constrain the isotopic signatures of carbonate carbon and organic carbon with the mantle carbon, then... 

The metabolism of humic substances is a subject that has received little attention, particularly so for estuarine systems. However, the mass balance calculations of Berner (1982) suggest that a major portion of the terrigenous organic carbon entering the marine environment must be metabolized in some manner the possibility that some fraction of this metabolism occurs in estuaries must therefore be considered. 

By constraining the fraction of the total FeS that is from SO4- reduction based on isotope mass balance, the amount of CO2 produced from respiration of Fe3+ can then be calculated from the remaining portion of the total organic carbon oxidized. 

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