Surface Reactions of Disinfectants

With the exception of activated carbon, not much work has been reported on the reactions of disinfectants at surfaces of the types expected to be encountered in water treatment, although reactions of free chlorine with the organic matter at the surfaces of several natural sediments have been shown to produce trihalomethanes (Uhler and Means, 1985). Activated carbons have long been known to be potent catalysts of redox (cf. Austin et al., 1980) and other reactions such as eliminations 

Other phenolic compounds underwent similar reactions. GAC after application of either free or combined chlorine became capable of promoting reactions such as hydroxylation of the aromatic ring, oxidation to phenols, chlorine substitution, carboxylation, and oxidative coupling (dimer and trimer formation). The formation of chlorohydroxybiphenyls ( hydroxylated PCBs 113) by dimerization of chloro- 

The free-radical character of GAC was further demonstrated by reactions of resorcinol (22). After absorption to GAC columns and treatment with either HOCl or CIO2, resorcinol reacted to afford a single major product, the dichlorocyclopen- 

The only report on the reactions of GAC-sorbed nitrogen compounds (Hwang et al., 1990) similarly indicated that sorbed anilines were converted by HOCl to oxidative coupling products such as azobenzenes (89), unlike solution reactions with HOCl that led to ring substitution. Additional compounds such as formanilides and acetanilides were also identified in some cases the mechanisms of formation of these N-substituted derivatives are unknown, although similar N-acyl derivatives have been reported to occur during the metabolism of anilines (Freitag et al., 1984). 

Gas chromatographic-mass spectrometric analysis of chlorination effects on commercial coal-tar leachate. Anal. Chem. 52, 1825-1828. 

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