General acid catalysis of monochloramine disproportionation
A fundamental understanding of chloramine chemistry is important in the control of water and waste water disinfection, biofouling in power plants, and in assessing the fate of chlorinated effluents discharged into the environment. This paper presents experimental results showing that monochloramine disproportionation, which results in the formation of dichloramine, involves a general acid catalyzed reaction pathway. Rate constants characterizing the effect of hydrogen ion, phosphate, and sulfate were determined by measuring the rate of monochloramine disappearance under pH conditions, which simplified interpretation of results. These rates constants were used to develop a linear free energy relationship that was used to predict the effect of carbonate and silicate. Predictions indicate that carbonate, and possibly silicate, may significantly increase the rate of acid-catalyzed disproportionation at concentrations and pH values typical of many drinking waters. Since this reaction may govern the overall rate of oxidant loss, appropriate consideration must be given to the presence of potential proton donors when predictions relating to chloramine speciation and fate are made on the basis of reaction models or when the results of studies with chloramine solutions are evaluated.
- Research Organization:
- Univ. of Iowa, Iowa City (USA)
- OSTI ID:
- 6604029
- Journal Information:
- Environ. Sci. Technol.; (United States), Vol. 22:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLORAMINES
CATALYSIS
DRINKING WATER
CHLORINATION
CARBONATES
ENVIRONMENTAL EXPOSURE PATHWAY
HYDROGEN IONS
PH VALUE
PHOSPHATES
SILICATES
WATER CHEMISTRY
AMINES
CARBON COMPOUNDS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
HALOGENATION
HYDROGEN COMPOUNDS
IONS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
SILICON COMPOUNDS
WATER
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)