Carbonate associated

Brasquet, C., Roussy, J., Subrenat, E. and Le Cloirec, P., Adsorption of micropollutants onto fibrous activated carbon Association of ultrafiltration and fibers, Water Sci. Technol., 1996, 34(9), 215 222. 

The recent report of wave-like patterns of bacteria and water soluble carbon associated with wheat roots (58) which were not strongly correlated with each other or with lateral root formation pose a challenge for models. So do the reports of highly dynamic and erratic population fluctuations of individual pseudomonad clones on sugar beet roots (59). 

Palladium/charcoal also could serve as a catalyst for Sonogashira reactions of peptides in aqueous media. Recently, Granja et al. used palladium/carbon associated with 4-diphenylphosphinobenzoic acid (4-DPPBA) or triphenylphosphine ligand to catalyze such a reaction in aqueous DMF (Eq. 4.16).34... 

Anderson, G. M. and G. Garven, 1987, Sulfate-sulfide-carbonate associations in Mississippi Valley-type lead-zinc deposits. Economic Geology 82,482 488. 

The effect of storage of water samples before determination of nitrogen and carbon associated with particulate matter was investigated. Freezing of the samples, and storage at 5°C, both affected the results obtained, but changes were minimized if the samples were filtered immediately after collection and the particulate matter stored on the filter paper. It is recommended that samples for determination of particulate carbon and nitrogen should be filtered immediately, and analysed as soon as possible. 

The role of organic carbon associated with sediments is still unclear. Many studies have shown that there is a good correlation between the organic carbon content and LAS sorption [2,3,20,36,38], but at... 

More complex substances, however, showed higher degrees of pyrolytic conversion. In aerosol samples collected from the combustion of distillate and residiaal oil, 31 and 25% respectively of the organic carbon underwent pyrolytic conversion to elemental carbon. Lesser amounts of conversion were observed for leaded and unleaded auto exhaust samples, and no conversion occurred in a diesel truck exhaust sample. Biological samples also showed large degrees of conversion e.g., 45% of the carbon associated with wood fiber was pyrolytically converted to elemental carbon. 

Chave, K. E. Carbonates Association with organic matter in surface seawater. Science 148, 1723-1724 (1965). 

Suess, E. Interaction of organic compounds with calcium carbonate. II. Organo-carbonate association in recent sediments. Geochim. Cosmochim. Acta 37, 2435—2447 (1973). 

The CP MAS DD 13C NMR spectrum at 23 °C is shown in Fig. 81. The 166.9, 136.8, 127.3 and 17.4 ppm lines correspond to the C = 0 carbons, unprotonated and protonated aromatic carbons, and methyl carbons, respectively. The set of lines at 46.3, 40.7, 32.3 and 27.4 ppm correspond to aliphatic CH and CH2 carbons. The temperature dependence of the t /2 values of these aliphatic carbons is shown in Fig. 82. The carbons associated with the 40.7 and 43.6 ppm lines, whose onset of motions occurs above 100 °C, should correspond to the CH2 carbons in a position with respect to the amide group. Consequently, the 27.4 and 32.3 ppm lines, associated with carbon atoms which undergo motions at temperature equal or higher than 20 °C, should correspond to the central CH2 carbons of the aliphatic sequence. 

There are several natural processes that can remove arsenic from groundwaters and other natural waters. These processes were introduced in Chapter 3 and include (1) precipitation and association with sulfides, (2) sorption on clay minerals, and (3) carbonate associations. This section discusses these processes in further detail. Additional discussions occur in Chapter 7, where some of the processes are utilized in treatment technologies for removing arsenic from water. 

Several of the minor components of coal are of importance, because of the quantity present on occasion, but more so in some cases by virtue of the special properties they possess which are undesirable when the coal is used for certain purposes. For example, to arrive at a correct figure for the combustible carbon in coal, it is necessary to apply a correction for the quantity of carbonate associated with the sample. Combustion analyses determine only the total carbon. Again, coking coals should have low phosphorus content, and anthracites used for malting should contain only very small quantities of arsenic, so that the determination of these elements becomes necessary in certain cases. Since both are found normally in small amounts, they are not included in the general statement of the ultimate analysis but are reported separately. 

Lewtas, J., Pang, Y., Booth, D., Reimer, S., Eatough, D.J. and Gundel, L (2001) Comparison of sampling methods for semi-volatile organic carbon associated with PM2.5. Aerosol Science and Technology, 34, 9-22. 

There are major differences in the chemical compositions of DOM isolated by XAD resins and ultrafiltration (Table I). In rivers and in the ocean, humic substances (XAD isolation) are depleted in N relative to UDOM. The C/N ratios of UDOM are more representative of bulk DOM than those of humic substances. Most of the functional groups identified by NMR are found in more than one class of compounds, so in most cases specific functional groups are not assigned to a particular group of biochemicals. However, in some circumstances it is possible to estimate the fraction of carbon associated with a biochemical class, such as carbohydrates. Carbohydrates are the most abundant polyalcohols in nature, and the ratio (4-5 1) of areas associated with NMR peaks at specific chemical shifts [e.g., 72 ppm (C—O) -102 ppm (O—C—O)] indicates that carbohydrates are their primary source (see Table I for references). In general, humic substances are depleted in carbohydrates (C—O and O—C—O) and enriched in aromatic and unsaturated C (C=C) relative to UDOM (Table I). As mentioned earlier, humic substances are relatively hydrophobic components of DOM, and it is consistent that they are depleted in N and carbohydrates and enriched in aromatic components. The UDOM fraction includes more hydrophilic components that are relatively enriched in N and carbohydrates. Humic substances from the ocean are enriched in aliphatic C (C—C) relative to UDOM, and this could reflect the more hydrophobic nature of the humic substances. 

It should be clear that when the terminal group of any Rhodonine responds as an alcohol, the oxygen and carbon associated with the side chain will respond in a manner similar to an aldehyde. The converse is also true. 

From a quantitative viewpoint, it is evident that the relative intensities of the resonances from carbons associated with branches and end groups can be compared to the intensity for the major methylene resonance, "n", at 30.00 ppm to determine branch concentrations and number average molecular weight or carbon number. The following definitions are useful in formulating the appropriate algebraic relationships ... 

Thus Korzhinskiy s (1940, 1957) well known conclusion that there is a systematic increase in activity of carbon dioxide with depth finds new theoretical substantiation. It is to be expected that as pressure (depth) increases, if the temperature remains constant silicate mineral associations will be replaced by carbonate associations even in those cases where the composition of the water-carbon dioxide fluid Tcoj- Hjo)... 

Similar ideas have also been expressed recently by other investigators of the BIF. Klein (1973) pointed out that in the Labrador Trough some parts of the section of the BIF, of quartz-carbonate composition, may have been involved in reactions which produced silicates of the metamorphic series, while in other places only recrystallization of the quartz-carbonate associations with or without magnetite occurred. In the author s opinion this indicates that the chemical potential of COj varied from place to place in the course of metamorphism and, consequently, COj could not have been an ideally mobile component at any moment of time. Perry et al. (1973) believe that in the BIF of Biwabik, Minnesota, individual bands behaved as isolated subsystems and that different minerals formed in each band depending on the composition of the original unmetamorphosed rocks. 

Bishop J. K. B. (1988) The barite-opal-organic carbon association in oceanic particulate matter. Nature 332, 341-343. 

---