Stoichiometry and mechanism of the chromium(II)-peroxydisulfate reaction

UV-activated persulfate oxidation and regeneration of NOM-Saturated granular activated carbon

“…It has been well established that the persulfate anion can be activated to generate $SO À 4 as shown in R3 (House, 1962). Also, the presence of $SO À 4 in aqueous solution can result in radical interconversion reactions to produce the hydroxyl radical (OH) (Eo ¼ 2.7 V) in accordance with the reactions shown in R4 and R5 (Pennington et al, 1968;Norman et al, 1970;Hayon et al, 1972). Under acidic conditions, the breakdown of persulfate into sulfate free radicals can be further acid catalyzed as shown in R6 and R7 (House, 1962).…”

Reductions of hexabromoiridate(IV) by chromium(II) and by pentacyanocobaltate(II). Evidence for bromide-bridged binuclear intermediates

“…Although Cr2+ has an overwhelming tendency to react via an inner-sphere mechanism, substitution into the coordination sphere of chromium(II) may be bypassed for very reactive oxidants, and an outer-sphere mechanism becomes operative. 10 Only the lower limit of 106 M"1 s"1 can be placed on the rate constants for the outer-sphere reactions of Cr2+ with IrCl62" or IrBr62", but it is likely that these rate constants are appreciably higher. A calculation of ku, the rate constant for the outer-sphere reaction between IrCl62" and Cr2+, can be made using Marcus' cross relation11 ki2=(knk22k12f)112 (10) log/= (logK12)2/4 log (knk22IZ2) (l l)…”

Sulfate radical-based degradation of polychlorinated biphenyls: Effects of chloride ion and reaction kinetics

“…Details concerning the Electron paramagnetic resonance (EPR) and second order rate constants of PCBs are provided in Text S1. Table 1 summarizes the principal reactions in persulfate system along with their rate constant [30][31][32]. On the basis of these reactions, the radical distributions can be predicted by pseudosteady-state assumption.…”