Kinetics and mechanism of the oxidation of sulfur(iv) by iron(iii) at metal ion excess

Lente, Gábor; Fábián, István

doi:10.1039/b107263c

Cited by 52 publications

(50 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[6][7][8] But Fe(III) is known to oxidize S(IV) also in the absence of oxygen. Far fewer studies have dealt with this process, [9][10][11][12][13][14][15][16] and no consensus has been reached regarding the relevant mechanism. This reaction in de-aerated solutions is the subject of the present critical analysis.…”

Section: Introductionmentioning

confidence: 99%

The oxidation of sulfur(iv) by reaction with iron(iii): a critical review and data analysis

Warneck

2018

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

The dependences on ionic strength of the hydrolysis constants of Fe and of the first dissociation constant of sulfurous acid are briefly reviewed. The data are needed to derive from apparent stability constants reported in the literature the stability constants for the three iron-sulfito complexes defined by the equilibria (c1) FeOH + HSO = FeSO + HO, (c2) FeSO + HSO = Fe(SO) + H, (c3a) Fe(SO) + HSO = Fe(SO)H, where K = 1982 ± 518 dm mol, K = 0.72 ± 0.08, K = 189 ± 9 dm mol (ionic strength μ = 0.1 mol dm). The rapid formation of these complexes is followed by a slower decomposition leading to the formation of SO radicals; the associated rate coefficients are k = 0.19 s, k ≈ 0.04 s, and k ≈ 0.08 s, respectively. The subsequent reaction leads to dithionate and sulfate as products. Overall rates and product yields from a variety of studies of the slow reaction are found to be consistent with a mechanism, in which the production of dithionate occurs mainly by the reaction of SO with FeSO and that of sulfate by the reaction of SO with FeOH and/or Fe. The role of copper as a catalyst is also analyzed. Rate coefficients for individual reactions are estimated from the data at low pH (μ = 1.0 mol dm) under conditions where the 1 : 1-complex is prevalent. They are extrapolated to lower ionic strengths for an analysis of the data obtained at higher pH to explore conditions when reactions of the higher complexes become important. The overall rate and the product yields of the reaction depend critically on the pH, the initial ratio of S(iv) to Fe(iii) and the ionic strength of the solution.

show abstract

Section: Introductionmentioning

confidence: 99%

The oxidation of sulfur(iv) by reaction with iron(iii): a critical review and data analysis

Warneck

2018

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…However, data of the intrinsic kinetics of sulfite oxidation are still scarce. Based on the uncatalyzed oxidation kinetics by Barron and other authors [2,3] , the macroscopic kinetics with catalysts of metal ions such as cobalt, manganese and ferrous was investigated respectively [4][5][6][7][8][9][10][11][12][13][14] . Although the catalysis effect of organic acids, which are cheap and cause little secondary pollution, has been studied by Zhao et al [15,16] , the mechanisms of the intrinsic reactions have not yet been investigated.…”

Section: Introductionmentioning

confidence: 99%

Intrinsic oxidation kinetics of sulfite catalyzed by peracetic acid under different water quality and light conditions

Wang

Zhao

et al. 2009

Sci. China Ser. B-Chem.

View full text Add to dashboard Cite

Oxidation of sulfite is an important process in wet flue gas desulfurization. Using highly purified water or distilled water as a reaction medium and a transparent or an opaque intermittent reaction apparatus, the intrinsic oxidation kinetics of sulfite catalyzed by peracetic acid was investigated under four different conditions. The reaction order of the reagents and the activation energy were obtained. The results indicate that water quality and light have no obvious effects on the reaction order and activation energy, but have an influence on the reaction rate constant. The mechanism of the intrinsic reaction is proposed. The results derived with this mechanism are in good agreement with the experimental results.light, water character, peracetic acid, catalyzed oxidation, sulfite, kinetics

show abstract

“…The value of ε (364 M −1 cm −1 ) and K a (0.0181 M) were known from previous studies, 35 the path length of the cell used was 1.000 cm. The initial rate of absorbance change was easily determined by linear fitting of a suitable initial portion as the curves were close to zeroth order.…”

Section: Detailed Kinetic Studiesmentioning

confidence: 99%

“…It is now widely accepted that the most efficient mechanisms involve radical chain mechanisms, in which the primary role of the catalyst is to initiate the chains, with some additional significance in chain propagation steps. The chain initiation can both be chemical 21,35 and photolytic, 38,40 the most important aspect is that it should involve a one-electron oxidation of sulfur(IV) to sulfite ion radical. The products formed in the decomposition of a metal (such as iron) sulfito complex or highly reactive species generated as a result of exposure to light can provide such a pathway.…”

Section: Introductionmentioning

confidence: 99%

“…36,39 In addition, several autoxidation processes with chain mechanisms have been studied including the catalytic effect of iron(III), 21,35 and photocatalysis in the presence of cerium(III) 38 and iodide 40 ions. The chain carriers common to the different systems were sulfite ion radical (SO 3 −• ), sulfate ion radical (SO 4 −• ), and peroxomonosulfate ion radical (SO 5 −• ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of the autoxidation of sulfur(iv) co-catalyzed by peroxodisulfate and silver(i) ions

2014

Self Cite

View full text Add to dashboard Cite

Kinetics and mechanism of the oxidation of sulfur(iv) by iron(iii) at metal ion excess

Cited by 52 publications

References 51 publications

The oxidation of sulfur(iv) by reaction with iron(iii): a critical review and data analysis

The oxidation of sulfur(iv) by reaction with iron(iii): a critical review and data analysis

Intrinsic oxidation kinetics of sulfite catalyzed by peracetic acid under different water quality and light conditions

Kinetics of the autoxidation of sulfur(iv) co-catalyzed by peroxodisulfate and silver(i) ions

Contact Info

Product

Resources

About