Kinetics of reactions in solutions containing monochloramine and bromide

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • A. Bousher
  • P. Brimblecombe
  • D. Midgley

Detail(s)

Original languageEnglish
Pages (from-to)1049-1058
Journal / PublicationWater Research
Volume23
Issue number8
Publication statusPublished - Aug 1989
Externally publishedYes

Abstract

The reactions of monochloramine in saline solutions containing bromide have been investigated. Monochloramine oxidizes the bromide ion via NH3Cl+ formation. The rate constant for the second-order reaction was found to be 6 ± 1 × 104 mol-1 dm3 s-1 at 25°C. Further rapid reactions follow, resulting predominantly in the formation of NHBr2 NHBr2 - and NClBr- at pH ∼ 7. The distribution of these species appears to be thermodynamically controlled and dependent upon the pH, the ionic strength and chloride/bromide ratio. The equilibrium constants at 25°C for NBr2 - and NClBr- formation with respect to NHBr2 were estimated to be H+ NBr2 -/[NHBr2] = 1.3 ± 0.1 × 10-7 mol dm-3 and H+NClBr- Br-/[NHBr2] Cl- = 6.1 ± 0.2 × 10-10 mol dm-3, respectively. These species decay through a series of reaction steps resulting in nitrogen formation. In unbuffered solutions, these reactions can lower the pH sufficiently for Br3 - formation to occur. © 1989.

Research Area(s)

  • bromide, bromochloramine dissociation, dibromamine dissociation, kinetics, monochloramine, tribromide ion

Citation Format(s)

Kinetics of reactions in solutions containing monochloramine and bromide. / Bousher, A.; Brimblecombe, P.; Midgley, D.

In: Water Research, Vol. 23, No. 8, 08.1989, p. 1049-1058.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal