Extract of treated water

Two approaches to the identification of mutagenic compounds in drinking water are described in this chapter. The first involves HPLC fractionation of extracts of treated water combined with mutagenicity testing of the fractions. Fractions of a mutagenic extract of chlorinated water were compared with nonmutagenic fractions of the same water sampled before final chlorination to focus on differences between the two, especially substances present only in mutagenic extracts and fractions. 

Fractionation of XAD-Ethyl Ether Extracts of Treated Water. 

Second stage fractionation was carried out on columns containing Spherisorb-CN (3 X [25 cm X 4.6 mm i.d.]) with an eluent of 3 isopropyl alcohol in n-hexane for fraction 2 and 7 isopropyl alcohol in n-hexane for fraction 3 (see HPLC Fractionation of Extracts of Treated Water and Figures 3 and 4 for details of fractionation). The injection volume was 25 pL (equivalent to 7.5 L of water sample), and 12 repeat injections were made for each fraction. 

HPLC Fractionation of Extracts of Treated Water. Capillary GC-MS analysis of the XAD-2/ethyl ether extracts of water sampled before and after final chlorination showed no significant difference that could account for the mutagenic activity observed after chlorination. These results indicate that the mutagenic compounds present in the extracts of drinking water are not readily amenable to analysis by GC-MS. However, the possibility cannot be excluded that the mutagenic compounds were present below the detection limit or that they were masked by other compounds. 

The mutagenic activities of the chlorinated humic acid and amino acid solutions are of the same order of magnitude as that observed in treated water. (The low numbers of revertants at the higher dose levels indicate toxicity). Therefore, these compounds may be precursors of the mutagenicity that is observed in XAD-2/ethyl ether extracts of treated water and that is the direct result of chlorination in drinking water treatment. 

Figure 5. Comparison of TA100 mutagenic activities of XAD-2/ethyl ether extracts of treated water and chlorinated model compounds. O, treated water , amino acids A, humic acids (Fluka AG) , humic acids (aquatic) and A, humic acids (peat bogs). (Reproduced with permission from reference 16. Copyright 1986 Water Research Centre.)...

Manganese oxides have been used to remediate contaminated soils as well. Hydrous manganese oxides decreased Cd and Pb in rye grass (Lolium spp.) and tobacco (Nicotiana tabacum L.) from soils with pH 7.4-7.8 (Mench et al., 1994). Cadmium concentrations decreased in water and in 0.1 M Ca(N03)2 and acetic acid extracts of treated soils (Mench et al., 1994). 

In the flotation device, the flow of charged air bubbles acts as collector and transporter of ionic impurities of treated water. Through the bubble-film extractor, this flow is removed from treated water. So, the mineral composition of treated water can be corrected, and the target mineral impurities can be extracted. The efficiency of demineralization of treated water can be evaluated if the relationship of bubble charge density upon pH and ionic concentration of water is known. An appropriate empiric equation is the following ... 

In the commercial extraction of alkaloids from the drugs in which they exist, the powdered drug, or an alcoholic extract of it, is treated with an alkali such as ammonia or lime to liberate the alkaloid and the alkaloid is then extracted by means of an organic solvent. The crude material thus obtained is purified and finally crystallized either as the base itself or as its water-soluble salts. 

The experimental details for mono-M-propylanillne are as follows. Reflux a mixture of 230 g. of aniline and 123 g. of n-propyl bromide for 8-10 hours. Allow to cool, render the mixture alkafine, and add a solution of 150 g. of zinc chloride in 150 g. of water. Cool the mixture and stir after 12 hours, filter at the pump and drain well. Extract the thick paste several times with boiling light petroleum, b.p. 60-80° (it is best to use a Soxhlet apparatus), wash the combined extracts successively with water and dilute ammonia solution, and then dry over anhydrous potassium carbonate or anhydrous magnesium sulphate. Remove the solvent on a water bath, and distil the residue from a Claisen flask with fractionating side arm (well lagged). Collect the n-propyl-aniline at 218-220° the yield is 80 g. Treat the pasty solid zincichloride with an excess of. sodium hydroxide solution and steam distil 130 g. of pure aniline are recovered. 

Decant the liquid layer into a 2 5 litre flask, and dissolve the sodium derivative of acetylacetone in 1600 ml. of ice water transfer the solution to the flask. Separate the impiue ethyl acetate layer as rapidly as possible extract the aqueous layer with two 200 ml. portions of ether and discard the ethereal extracts. Treat the aqueous layer with ice-cold dilute sulphimic acid (100 g. of concentrated sulphiu-ic acid and 270 g. of crushed ice) until it is just acid to htmus. Extract the diketone from the solution with four 200 ml. portions of ether. Leave the combined ether extracts standing over 40 g. of anhydrous sodium sulphate (or the equivalent quantity of anhydrous magnesium sulphate) for 24 hours in the ice chest. Decant the ether solution into a 1500 ml. round-bottomed flask, shake the desiccant with 100 ml. of sodium-dried ether and add the extract to the ether solution. Distil off the ether on a water bath. Transfer the residue from a Claisen flask with fractionating side arm (Figs. II, 24, 4r-5) collect the fraction boiling between 130° and 139°. Dry this over 5 g. of anhydrous potassium carbonate, remove the desiccant, and redistil from the same flask. Collect the pure acetji-acetone at 134r-136°. The yield is 85 g. 

The purified acid is recovered from the loaded organic stream by contacting with water in another countercurrent extraction step. In place of water, an aqueous alkafl can be used to recover a purified phosphate salt solution. A small portion of the purified acid is typically used in a backwashing operation to contact the loaded organic phase and to improve the purity of the extract phase prior to recovery of the purified acid. Depending on the miscibility of the solvent with the acid, the purified acid and the raffinate may be stripped of residual solvent which is recycled to the extraction loop. The purified acid can be treated for removal of residual organic impurities, stripped of fluoride to low (10 ppm) levels, and concentrated to the desired P2 s Many variations of this basic scheme have been developed to improve the extraction of phosphate and rejection of impurities to the raffinate stream, and numerous patents have been granted on solvent extraction processes. 

Carmine [1390-65-4] is the trade name for the aluminum lake of the red anthraquinone dye carminic acid obtained from the cochineal bug. The dye is obtained from the powdery form of cochineal by extraction with hot water, the extracts treated with aluminum salts, and the dye precipitated from the solution by the addition of ethanol. This water-soluble bright red dye is used for coloring shrimp, pork sausages, pharmaceuticals, and cosmetics. It is the only animal-derived dye approved as a colorant for foods and other products. 

Flynn and Treybal [Am. Inst. Chem. Eng. J., I,. 324 (1955)]. Continuous extraction of benzoic acid from toluene and kerosine into water baffled vessels, turbine agitators. Stage efficiency is correlated with agitator energy per unit of liquid treated. 

Isopropyl iodide (2-iodopropane) [75-30-9] M 170.0, b 88.9 , d 1.70, n 1.4987. Treated with bromine, followed by extraction of free halogen with aqueous Na2S203 or NaHS03, washing with water, drying (MgS04 or CaCl2) and distn. (The treatment with bromine is optional.) Other purification methods include... 

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