Environmental protection, aqueous

Shipment of hydrazine solutions is regulated in the United States by the Department of Transportation (DOT) which classifies all aqueous solutions between 64.4 and 37% N2H4 as "Corrosive" materials with a subsidiary risk of "Poison". Hydrazine has been identified by both the Environmental Protection Agency and the DOT as a hazardous material and has been assigned a reportable quantity (RQ) of 0.450 kg (1 lb) if spilled. Dmms for the shipment of these solutions must bear both the DOT specification "Corrosive" and "Poison" labels in association with the markings "RQ Hydrazine Aqueous Solution UN 2030." Aqueous solutions of 37% concentration or less are a hazard Class 6.1, UN 3293, Packing Group III and require "Keep Away From Food" placards and labels. 

Aqueous Phase Oxidation of Sludge using the Vertical Reaction Vessel System," report to U.S. Environmental Protection Agency, Washington, D.C.,Mar. 1987. 

The West-Gaeke manual method is the basis for the U.S. Environmental Protection Agency reference method for measurement of SO2 (6). The method uses the colorimetric principle i.e., the amount of SO2 collected is proportional to the amount of light absorbed by a solution. The collection medium is an aqueous solution of sodium or potassium tetrachloromercu-... 

Lloyd-Jones, P.J., Rangel-Mendez, J.R., and Streat, M., Mercury sorption from aqueous solution by chelating ion exchange resins, activated carbon and a biosorbent, Process Safety and Environmental Protection, 82 (4), 301-311, 2004. 

Wasik, S.P., Tewari, Y.B., Miller, M.M., Martire, D.E. (1981) Octanol/Water Partition Coefficients and Aqueous Solubilities of Organic Compounds. NBSIR 81-2406, report prepared for Office of Toxic Substances, Environmental Protection Agency, Washington, DC. 

The theoretical yield of the method is less than 100%, as only 80 - 90% of the aqueous phase is removed after back-extraction. The actual yield obtained by 54 Mn counting was 69.5 7.8%, and this can be allowed for in the calculation of results. Environmental Protection Agency standard seawater samples of known manganese content (4370 ng/1) gave good manganese recoveries (4260 ng/1). 

From a separation-process point of view, a fluid-fluid reaction is intended to enhance separation (e.g., preparation of feed for a subsequent process step, product purification, or effluent control for environmental protection). Examples include the use of ethanolamines for the removal of H2S and C02 (reactions (A) and (B) in Section 9.2), the removal of SO, by an aqueous stream of a hydroxide, and absorption of 02 by blood or desorption of C02 from blood. A solid catalyst may be involved as a third phase, as in hydrodesulfurization in a trickle-bed reactor. 

Environmental Protection Agency (22). Figure 1 is a plot of the sediment/aqueous concentration ratio versus time for this system. It is characterized by a rapid sorption process and a much slower sorption process which does not reach equilibrium until about 10 days after initial mixing of the sediment and chlorpyrifos solution. 

EPA. 1988e. Interim protocol for measuring hydrolysis rate constants in aqueous solutions. Washington, DC U.S. Environmental Protection Agency, Office of Research and Development. EPA/600/S3-88/014. 

Bromate has been classified as a human carcinogen by both the I/VRC (International Agency for the Research on Cancer) and the USEPA (United States Environmental Protection Agency) and is known to be toxic to fish and other aquatic life [11, 12]. Bromate could be produced in aquatic systems upon the oxidation of aqueous bromide. Controlled ozonation has been considered as an effective disinfectant tool in aquatic systems [13] but when sea water is subjected to ozonation, oxy-bromide ozonation by-products (OBP) are produced and these are important both in terms of their disinfection ability and also in relation to their potential toxicity. When seawater is oxidized, aqueous bromide (Br-) is initially converted to hypobro-mite (OBr ) which can then either be reduced back to bromide or oxidized further to bromate (Br03-) which is known to be toxic to fish and other aquatic life and classified as a human carcinogen. There has been thus a considerable interest in bromate analysis so that trace analysis of bromate in water has received considerable attention in recent years. 

Air sampling media, water samples, solid waste matrices, soil samples Liquid-liquid extraction or water dilution GC/MS 10 xg/L (aqueous) (EQL) Environmental Protection Agency (1996b) [Method 8270C]... 

Solid waste matriees Solvent extraction or direct injection (with azeotropic distillation) into capillary GC column GC/FID 9-21 pg/L (aqueous matrices) 0.08-0.20 mg/kg (solid matrices) Environmental Protection Agency (1996a) [Method 8015B]... 

Dichloromethane or methylene chloride is an Environmental Protection Agency priority pollutant. Its mode of human toxicity and carcinogenicity is described above. Dichloromethane has a high vapor pressure and a relatively high aqueous solubility of 150 mM (Dean, 1985), properties that contribute to its distribution in... 

We can estimate the pH of an aqueous solution very quickly by using a strip of universal indicator paper, which turns different colors at different pH values. More precise measurements are made with a pH meter (Fig. 10.10). This instrument consists of a voltmeter connected to two electrodes that dip into the solution. The difference in electrical potential across the electrodes is proportional to the pH (as will be explained in Section 12.11) so once the scale on the meter has been calibrated, the pH can be read directly. In the United States, the Environmental Protection Agency (EPA) defines waste as corrosive if its pH is either lower than... 

Chlorinated phenols are among the most important contaminants in the environment (aqueous systems and soils) due to their widespread use in industry and agriculture and for domestic purposes for over 50 years. It is well-known that chlorophenols are toxic at low levels. The more highly chlorinated phenols such as trichlorophenols and pentachlorophenol are also persistent. Five of the chlorophenols (2-chlorophenol, 2,4-dichlorophenol, 4-chloro-3-methylphenol, 2,4,6-trichlorophenol and pentachlorophenol) have been classified as priority pollutants by the US Environmental Protection Agency (EPA). 

The method for the manufacture of polypropylene by the Ziegler-Natta process, which has been in widespread use for several decades, involved some years ago a polymerization in a relatively volatile solvent, for example a light petroleum fraction. That was the drawback of this process, since in the separation and subsequent drying of the polymer formed the solvent could not be completely recovered. Problems are thus experienced in fulfilling environmental protection requirements. An additional obstacle was the large volume of aqueous waste that is generated during workup of the polymer suspension. 

Determination of Vinyl Monomer in Aqueous Effluents. Analytical Chemistry Branch, Southeast Environmental Research Laboratory, Environmental Protection Agency, Athens, GA, USA (1974). 

Programs such as QMPRPlus (SimulationPlus, Inc.) and WSKOWIN (EPISUITE available from the Environmental Protection Agency website, Syracuse Research Corporation, Inc.) can be used to predict aqueous solubility directly (see Chapters 3 and 4). As log Kow inversely correlates reasonably well with aqueous solubility for many compounds, programs that are available to predict log Kow may also be useful in preliminary screens for aqueous solubility. 

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