Kinetics and Mechanism of the Oxidation of Aqueous Hydrogen Sulfide by Peroxymonosulfate

Eric A. Betterton, Michael R. Hoffmann

Research output: Contribution to journalArticle

61 Scopus citations

Abstract

The stoichiometry and mechanism of the oxidation of aqueous S(−II) by HSO5 is similar to the oxidation of S(−II) by H2o2, but the rate of oxidation by HSO5 is 3-4 orders of magnitude faster than the corresponding reaction with H2O2. A two-term rate law of the following form is found to be valid for the pH range of 2.0-6.3: −d[S(−II)]/dt = k1[H2S][HSO5] + k2Ka1 [H2S] [HSO5]/ [H+], where k1 = 1.98 × 101 M−1 s−1, k2 = 1.22 × 104 M−1 s−1, and Ka1 = [H+][HS]/[H2S] = 2.84 × 10−8 M at 4.9 °C, μ = 0.2 M, and [S(−II)] = [H2S] + [HS] + [S2−]. At high pH and high [HSO5]/[S(−II)] ratios SO42− and H+ formation are favored, whereas at low pH and low [HSO5]/[S(−II)] ratios elemental sulfur (S8) is favored as the principal reaction product. Peroxymonosulfate is a monosubstituted derivative of hydrogen peroxide that is thermodynamically more powerful as an oxidant than H2O2 and kinetically more reactive. These properties make HSO5 a potentially important oxidant in natural systems such as remote tropospheric clouds and also a viable alternative to H2O2 for the control of malodorous sulfur compounds and for the control of sulfide-induced corrosion in concrete sewers.

Original languageEnglish (US)
Pages (from-to)1819-1824
Number of pages6
JournalEnvironmental Science and Technology
Volume24
Issue number12
DOIs
StatePublished - Dec 1 1990

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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