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The standard enthalpy of formation of peroxymonosulfate (HSO5−) and the standard electrode potential of the peroxymonosulfate-bisulfate couple

1982; Elsevier BV; Volume: 14; Issue: 4 Linguagem: Inglês

10.1016/0021-9614(82)90052-0

1096-3626

W.V. Steele, Evan H. Appelman,

Mine drainage and remediation techniques

The standard enthalpy of formation at 298.15 K of the aqueous peroxymonosulfate ion, HSO5−, has been determined by reduction of the ion in aqueous HI. The value obtained is ΔHfo(HSO5−, aq) = −(798.4 ± 2.5) kJ·mol−1. This enthalpy was combined with an estimated entropy for the aqueous ion to yield a standard electrode potential of (1.82 ± 0.03) V for the aqueous half-reaction: HSO5−>+2H++2e−=HSO4−+H2O This potential is substantially greater than that derived from electrochemical measurements and implies that HSO5− is a considerably more powerful oxidant than has been generally recognized.