Volatile organic chemicals/compounds

The commercialization by Kureha Chemical Co. of Japan of a new, highly attrition-resistant, activated-carbon adsorbent as Beaded Activated Carbon (BAC) allowed development of a process employing fluidized-bed adsorption and moving-bed desorption for removal of volatile organic carbon compounds from air. The process has been marketed as GASTAK in Japan and as PURASIV HR (91) in the United States, and is now marketed as SOLD ACS by Daikin Industries, Ltd. 

Clark, R. M. (1990). Unit process research for removing volatile organic chemicals from drinking water An overview. In Significance and Treatment of Volatile Organic Compounds in Water Supplies, (N. M. Ram, R. F. Christman, and K. P. Cantor, eds.), Lewis Publishers, Chelsea, ML... 

Several soil-vapor monitoring techniques are currendy being used to define areas of volatile organic chemical contamination. These procedures usually involve the collection of representative samples of the soil gas for analysis of indicator compounds. Maps marked with concentration contours of these indicator compounds can be used to identify potential sources to delineate the contaminated area. Indicator compounds (usually the more volatile compounds) are selected for each specific situation. For gasoline contamination, the compounds are usually benzene, toluene, ethylbenzene, and total xylene (BTEX). In the case of a fuel oil spill, the most commonly used indicator is naphthalene. Some laboratories have adapted the laboratory procedures used for quality analysis of wellhead condensate (i.e., normal paraffins) to include light-end (<8 carbons) molecular analysis. 

Passive samplers are widely used in monitoring volatile organic chemicals (VOCs) in groundwater. Such samplers have the potential to reduce costs of monitoring from the high levels associated with the use of pumps to sample the test wells. Moreover, the risk of loss of volatile analytes during sample transport and storage is substantially reduced once the compounds are accumulated in the sampler sorption phase. 

The effect of the various concentrations of SO2, CO2, CO, and volatile organic chemical vapors on the conductivity of compounds 42 and 43 in Fig. 30 was tested at different temperatures. The results showed that compound 42 is not sensitive for the gases investigated, with the exception of SO2 for which very high sensitivity was obtained. The response characteristics of 42 to the various concentrations (50-250 ppm) of SO2 at room temperature are shown in Fig. 30 [48]. 

Blank, L, Sensory relevance of volatile organic sulfur compounds in food. In Heteroatomic Aroma Compounds, ACS Symposium Series 826 (Reineccius, G.A., Reineccius, T.A., eds.), American Chemical Society, Washington, DC, pp. 25-53, 2002... 

Bauer U. 1981. [Human exposure to environmental chemicals Investigations of volatile organic halogenated compounds in water air food and human tissues. IV. Communication Calculation of... 

The transfer of well-known perfume brands into cosmetic formulations will lead to the challenge of maintaining the perfume impression despite possible interactions with cosmetic care compounds. Microemulsions have proven to be very efficient in this respect. For example, a clear aftershave microemulsion formulated with non-ionic surfactants and isoeicosane is almost non-interfering with the perfume impression [45]. Because of the trend to reduce the amount of volatile organic chemicals, ethanol-free perfume micro emulsions are under further development. Non-sticky, non-fatty and ethanol-free products can be obtained through the usage of vicinal diols such as 1,2-hexanediol in microemulsion formulations [46]. 

D. Mackay, W. Y. Shiu and K. C. Ma, Illustrated Handbook of Physical-Chemical Properties and Environmental Fate for Chemicals, Lewis Publishers, Boca Raton, FL. Vol. I, Monoaromatic Hydrocarbons, Chlorobenzenes and PCBs, 1992. Vol. II, Polynuclear Aromatic Hydrocarbons, Polychlorinated Dioxins, Bibenzofurans, 1993. Vol. Ill, Volatile Organic Chemicals. Vol. IV Oxygen, Nitrogen and Sulfur Containing Compounds. Vol. V Pesticide Chemicals 1997. 

Aromatic Hydrocarbons, Polychlorinated Dioxins, Bibenzofurans, 1993. Vol. Ill, Volatile Organic Chemicals. Vol. IV, Oxygen, Nitrogen and Sulfur Containing Compounds. Vol. V, Pesticide Chemicals, 1997. 

Strommen MR, Kamens RM (1999) Simulation of semivolatile organic compound microtransport at different time scales in airborne diesel soot particles. Environ Sci Technol 33 1738-1746 Thibodeaux LJ, Nadler KC, Valsaraj KT, Reible RR (1991) The effect of moisture on volatile organic chemical gas-to-particle partitioning with atmospheric aerosols-competitive adsorption theory predictions. Atmos Environ 25A 1649-1656 Thompson JD, Cramer CJ, Truhlar DG (2003) Predicting aqueous solubilities from aqueous free energies of solvation and experimental or calculated vapor pressures of pure substances. J Chem Phys 19 1661-1670... 

According to Mackay (1998), volatile organic chemicals (VOCs) are the most frequently detected organic contaminants in water supply wells in the United States. Of the VOCs, by far the most common are chlorinated hydrocarbon compounds. Conversely, petroleum hydrocarbons are rarely present in supply wells. This may be due to their in situ biodegradation. 

Many landfills contain VOCs (volatile organic chemicals). This group of chemicals includes benzene and toluene (both carcinogens), chlorinated hydrocarbons, such as carbon tetrachloride, and trichloroethylene, which previously was used as a dry-cleaning solvent. Even though these compounds are not very soluble in water, they do accumulate at the parts-per-million level. Their long-term effect on human health is unknown at this time. 

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