Ozone decomposition in water studied by pulse radiolysis. 1. HO/sub 2//O/sub 2//sup -/ and HO/sub 3//O/sub 3//sup -/ as intermediates. [Electron beams]

Journal Article · Thu Jun 07 04:00:00 EDT 1984 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j150656a026· OSTI ID:6674279

Buehler, R E; Staehelin, J; Hoigne, J

Pulse radiolysis allows one to selectively enter the chain mechanism for ozone decomposition in water by OH or O/sub 2//sup -/ and to study the elementary reactions involved. Details of the reaction mechanism of the first chain propagation step (O/sub 2//sup -/ + O/sub 3/) in the Weiss model have been resolved to include the two additional transients O/sub 3//sup -/ (lambda/sub max/ = 430 +/- 10 nm, epsilon/sub max/ = 2000 M/sup -1/ cm/sup -1/) and HO/sub 3/ (lambda/sub max/ = 350 +/- 20 nm, epsilon/sub max/ = 300 +/- 30 M/sup -1/ cm/sup -1/). The elementary steps are as follows: O/sub 2//sup -/ + O/sub 3/ ..-->.. O/sub 3//sup -/ + O/sub 2/, k = (1.6 +/- 0.2) X 10/sup 9/ M/sup -1/ s/sup -1/; O/sub 3//sup -/ + H/sup +/ in equilibrium HO/sub 3/ (a,b), k/sub a/ = (5.2 +/- 0.6) x 10/sup 10/ M/sup -1/ s/sup -1/, k/sub b/ = (3.7 +/- 0.3) x 10/sub 4/ s/sup -1/; HO/sub 3/ ..-->.. OH + O/sub 2/, k = (1.1 +/- 0.1) x 10/sup 5/ s/sup -1/. A pK(HO/sub 3//O/sub 3//sup -/) = 6.15 +/- 0.05 is derived. Phosphate buffer also takes part in the protonation/deprotonation of HO/sub 3//O/sub 3//sup -/: O/sub 3//sup -/ + H/sub 2/PO/sub 4//sup -/ in equilibrium HO/sub 3/ + HPO/sub 4//sup 2 -/ (a,b), K/sub a/ = (2.1 +/- 0.2) x 10/sup 8/ M/sup -1/ s/sup -1/, k/sub b/ = (2.0 +/- 0.3) x 10/sup 7/ M/sup -1/ s/sup -1/. Consequences of these high rate constants on the possible chain termination processes and on the possibility of interactions of organic solutes with the chain reactions are discussed.

• Research Organization: Swiss Federal Inst. of Tech., Zurich, Switzerland
• OSTI ID: 6674279
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 88:12; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AQUEOUS SOLUTIONS
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DECOMPOSITION
DISPERSIONS
ELECTRON BEAMS
EXPERIMENTAL DATA
HYDROXYL RADICALS
INFORMATION
IRRADIATION
KINETICS
LEPTON BEAMS
MIXTURES
NUMERICAL DATA
OZONE
PARTICLE BEAMS
PEROXY RADICALS
PULSED IRRADIATION
RADIATION CHEMISTRY
RADIATION EFFECTS
RADICALS
REACTION KINETICS
SOLUTIONS