Environmental Protection Agency anions

Amination of aromatic nitro compounds is a very important process in both industry and laboratory. A simple synthesis of 4-aminodiphenyl amine (4-ADPA) has been achieved by utilizing a nucleophilic aromatic substitution. 4-ADPA is a key intermediate in the rubber chemical family of antioxidants. By means of a nucleophibc attack of the anilide anion on a nitrobenzene, a o-complex is formed first, which is then converted into 4-nitrosodiphenylamine and 4-nitrodiphenylamine by intra- and intermolecular oxidation. Catalytic hydrogenation finally affords 4-ADPA. Azobenzene, which is formed as a by-product, can be hydrogenated to aniline and thus recycled into the process. Switching this new atom-economy route allows for a dramatic reduction of chemical waste (Scheme 9.9).73 The United States Environmental Protection Agency gave the Green Chemistry Award for this process in 1998.74... 

The remainder of the modified parfait column consisted of an MSC-1 cation-exchange and an A-162 anion-exchange bed. The elution conditions for these beds were modified to minimize contamination of eluates and to selectively desorb organic anions and cations. With the modified protocol, 20 model compounds (Table I), selected by the U.S. Environmental Protection Agency (USEPA) Health Effects Research Laboratory (HERL), were used to evaluate the recovery efficiency of the method. Recoveries were determined in the presence of 2 ppm of a humic acid supplied by HERL. 

The Environmental Protection Agency US [106] have published a standard method for the determination of anions in surface waters. 

O Dell, J.W., Pfaff, J.D., Gales, M.E. McKee, G.D. (1984) Test method. The determination of inorganic anions in water by ion chromatography - Method 300.0 . US Environmental Protection Agency, Cincinnati, OH. 

Levels of [N03] in waste water are controlled by legislation, limits being recommended by the World Health Organization, the Environmental Protection Agency (in the US) and the European Community. Nitrites, because of their toxicity, must also be removed. Methods of nitrate removal include anion exchange, reverse osmosis (see Box 15.3), and denitrification. The last process is a biological one in which certain anaerobic bacteria reduce [N03] and [N02] to N2 ... 

Anion exchange for arsenic removai is one of the BAT (best available technology) recommended by the U.S. Environmental Protection Agency (EPA). Extensive studies, both at the bench and pilot scale have shown that for a source water containing <120 mg/L sulfate and <500 mg/L TDS, ion exchange may be the arsenic-removal process of choice (3,4,19-21). 

Certain anionic polyacrylamides are approved by the U.S. Environmental Protection Agency for clarification of potable water. Polymer treatment also allows filters to operate at higher hydraulic rates. The function of clarification is not explained by a simple mechanism. The long-chain linear polymer apparently functions to encompass a number of individual fine particles of the dispersed material in water, attaching itself to the particles at various sites by chemical bonds, electrostatic attraction, or other attractive forces. Relatively stable aggregates are thus produced, which be removed by filtration, settling, or other convenient means. 

CE has been applied to anion and cation analysis during the last 15 years. This technique constitutes a viable alternative to ion chromatography. The United States Environmental Protection Agency (US EPA) has already approved a CE method for determining hexavalent chromium (in Region VII) and is currently... 

Hautman, D.P. Munch, D.J. Frehis, Ch. Wagner Pepich, B.V. Review of the methods of the U.S. environmental protection agency for the bromate determination and validation of Method 317.0 for disinfection byproduct anions and low-level bromate. J. Chromatogr. 2001, 920, 221-226. 

US Environmental Protection Agency. In USEPA Method 300.0. The Determination of Inorganic Anions in Water by Ion Chromatography USEPA Cincinnati, OH, 1993. 

The focus of a US EPA (Environmental Protection Agency) sponsored project was to separate anionic and cationic dyes from process water and chemicals by reverse osmosis and to re-use the concentrated dyes for coloration of automotive fabrics, with addition of some fresh dye if necessary (Brandon, 1980). It was not always possible, however, to generate sufficient recovered dye nor to completely adjust the desired shade. It was also difficult to match color shades when very dark concentrate was used. 

Determination of Inorganic Anions in water by Ion Chromatography, U.S. Environmental Protective Agency 300.0 Cincinnati, Ohio 1993. 

Pfafif, J. D. Method 300.0 Determination of Inorganic Anions by Ion Chromatography, Environmental Monitoring Systems Laboratory, Office of Research and Development, U S. Environmental Protection Agency Cincinnati, OH, 1993. 

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