Humic substances reactions with chlorine

Gaffney et al. 1987). Cyanogen chloride is formed in drinking water from reaction of humic substances with chloramine produced during chlorination (Jacangelo et al. 1989 Ohya and Kanno 1987). 

Tribromomethane [75-25-2] (bromoform), CHBr3, is usually sold mixed with up to 3—4% ethanol as a stabilizer. The pure liquid has mp, 7.7°C bp, 149.5°C cP A, 2.8912 g/mL 19D 1.5980 (87). Water solubility is about 0.3 g/100 g at 25°C. Bromoform is prepared from chloroform by the replacement procedures indicated (88). The classical method of preparation involves reaction of acetone and sodium hypobromite the latter may be generated from sodium hypochlorite and a bromide (89). Uses have been found in syntheses, in pharmacy as a sedative and antitussive, in gauge fluids, and as a dense liquid for separating minerals. Traces of bromoform and bromochloroforms are likely to be present in municipal waters and wastes as a result of chlorination in the presence of naturally occurring bromide ions and humic substances (90). Removal can be accomplished by adsorption on activated charcoal. 

Reactions of Chlorine and Chlorine Dioxide with Humic Substances 694... 

Johnson, J. D., D. L. Norwood, and R. F. Christman. 1982. Reaction products of aquatic humic substances with chlorine. Environ. Health Perspect. 46 63-71. 

A major problem with the use of chlorine as a disinfection agent is by-product production from the reaction of chlorine or bromine generated from chlorine with organics in water. The most common such by-products are the trihalomethanes including chloroform, HCCI3, and dibromochlo-romethane, HCBr2Cl, noted as water pollutants in Chapter 4, Section 4.13. Humic substances are common precursors to chlorinated by-products their removal before water chlorination prevents the formation of organochlorine by-products. 

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