Flash photolysis study of sulfite, thiocyanate, and thiosulfate ions in solution

Thiosulfate as an Oxidation Inhibitor in Flue Gas Desulfurization Processes: A Review of R&D Results

“…23 Thiosulfate oxidation probably occurs by reaction of thiosulfate with a free radical to form a thiosulfate radical (Reaction 3), followed by second order reaction of thiosulfate radicals to give tetrathionate (Reaction 4). The measured rate of Reaction 4 (3.5 X 10 9 M" 1 sec" 1 , 8 X 10 8 M" 1 sec" 1 ) 34 -35 is comparable to the rates of other radical terminating reactions involving sulfite radical (SC>3~) or peroxymonosulfate radical (SO5-). 36 In the presence of sulfite, tetrathionate is rapidly converted to trithionate by the reversible reaction:…”

“…The effect of ionic strength attributed to cations (I 2 ) was taken from Rochelle 34 ( Figures 3 and 4). Owens' data are correlated by:…”

Free-radical chemistry of sulfite.

“…The S03 radical has been produced by oxidation sulfite with Ce4+ in acid solution (39)(40)(41), by reacti of sulfite with rad.icals produced by Fenton-type i agents, e.g., OH, NH2, and S4-(from the reaction Ti + with H202, NH2OH, S2082, respeetively) (42), reaction with radiolytically produced OH radicals other oxidizing radicals (43)(44)(45)(46)(47) OH + S02 -R OH-+ SOgby photoionization of sulfite directly (3,48,49) or throu photosensitizers (49) S032-+ hv -SO-+ eor by photolysis of dithionate (50) or thiosulfate (5 The S03-single-line ESR spectrum has been detect by using all ofthe above techniques (39)(40)(41)(42)46,47,49,5 as well as in biochemical systems such as horseradi peroxidase-hydrogen peroxide (52) or prostaglan( hydroperoxidase (53). Most of these studies report a g factor for S03 around 2.0030, except experimer with Ce4+ in acid solutions, where g = 2.0022 has be measured (39)(40)(41).…”

The Effect of Sulfurhexafluoride on the Photochemistry of Aqueous Solutions

“…Although flash photolysis (4,5) has been used to identify eaq-, the principal technique in its quantitative measure has been the use of N 2 0 as a scavenger in the reaction [I 1 e.,-+ NzO -t N2 + 0 -( + H 2 0 e OH + OH-) From reaction 1 it is easily seen that +(N2) should give a quantitative measure of +(e,,-), provided that there are no competing solutes or N2 producing reactions.…”