Studies in the Radiolysis of Ferrous Sulfate Solutions: II. Effect of Acid Concentration in Solutions Containing Oxygen

Allen, Augustine O.; Hogan, Virginia D.; Rothschild, Walter G.

doi:10.2307/3570576

Cited by 32 publications

(7 citation statements)

References 7 publications

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“…Thus, the results reported by Rush and Bielski are entirely consistent with the mechanism proposed in the present work. Although earlier works have reported values for the rate constant of the Fe 3+ -HO 2 • reaction considerably higher, [35][36][37][38][39] the strong base catalysis found in the present work for the Fe(III)-H 2 O 2 reaction suggests that the low value reported by Rush and Bielski might be more correct. It seems that those higher values might correspond to the reaction of Fe 3+ with a mixture of HO 2 • and O 2 •rather than with HO 2 • alone.…”

Section: Discussioncontrasting

confidence: 74%

Iron(III)−Hydrogen Peroxide Reaction: Kinetic Evidence of a Hydroxyl-Mediated Chain Mechanism

Perez‐Benito

2004

J. Phys. Chem. A

110

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The kinetics of decomposition of H 2 O 2 catalyzed by Fe 3+ in aqueous solution in the presence of HNO 3 has been followed by permanganate titration and studied by the initial-rate method. In the experimental range [H 2 O 2 ] 0 /[Fe 3+ ] ) 41-2028 used in this study, the initial rate follows the lawBoth rate constants k and k′ decrease with increasing ionic strength, and the corresponding apparent activation energies are 146 ( 10 and 88 ( 21 kJ mol -1 . The experimental rate law strongly suggests a radical-chain mechanism, with Fe 2+ , HO • , HO 2 • , and O 2 •-as propagating intermediates. At high values of the [H 2 O 2 ] 0 /[Fe 3+ ] ratio two different reactions compete as chaintermination steps (dismutation of HO 2 • radicals and reduction of HO 2 • by Fe 2+ ), whereas at lower values of that ratio a third chain-termination step (reduction of HO • by Fe 2+ ) also contributes. Thus, the kinetics of this reaction can be considered as an indirect proof of the participation of hydroxyl radicals in the mechanism.

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Section: Discussioncontrasting

confidence: 74%

Iron(III)−Hydrogen Peroxide Reaction: Kinetic Evidence of a Hydroxyl-Mediated Chain Mechanism

Perez‐Benito

2004

J. Phys. Chem. A

110

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“…Perhydroxyl radicals (HO 2 • ) formed in reactions and also participate in the Fenton chain reaction. They can either react with Fe III , Fe II or another HO 2 • (reactions , , , and ). Their proposed mechanism involving catalytic cycling between Fe II and trivalent iron (Fe III ) is nowadays referred to as “classical” or “free radical” Fenton chain reaction …”

Section: Introductionmentioning

confidence: 99%

“…• (reactions 7 13 , 8 14,15 , and 9 16 ). Their proposed mechanism involving catalytic cycling between Fe II and trivalent iron (Fe III ) is nowadays referred to as "classical" or "free radical" Fenton chain reaction.…”

mentioning

confidence: 99%

Investigation of the Iron–Peroxo Complex in the Fenton Reaction: Kinetic Indication, Decay Kinetics, and Hydroxyl Radical Yields

Wiegand

Orths

Kerpen

et al. 2017

Environ. Sci. Technol.

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The Fenton reaction describes the reaction of Fe(II) with hydrogen peroxide. Several researchers proposed the formation of an intermediate iron-peroxo complex but experimental evidence for its existence is still missing. The present study investigates formation and lifetime of this intermediate at various conditions such as different Fe(II)-concentrations, absence vs presence of a hydroxyl radical scavenger (dimethyl sulfoxide, DMSO), and different pH values. Obtained results indicate that the iron-peroxo complex is formed under all experimental conditions. Based on these data, stability of the iron-peroxo complex could be examined. At pH 3 regardless of [Fe(II)] decay rates for the iron-peroxo complex of about 50 s were determined in absence and presence of DMSO. Without DMSO and [Fe(II)] = 300 μM variation of pH yielded decay rates of about 70 s for pH 1 and 2 and of about 50 s at pH 3 and 4. Hence, the iron-peroxo complex becomes more stable with increasing pH. Furthermore, pH-dependent hydroxyl radical yields were determined to investigate whether the increasing stability of the intermediate complex may indicate a different reaction of the iron-peroxo complex which might yield Fe(IV) instead of hydroxyl radical formation as suggested in literature. However, it was found that hydroxyl radicals were produced proportionally to the Fe(II)-concentration.

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“…The most reliable chemical dosimeter is Fricke dosimeter which is widely used for calibration of gamma irradiation chamber [ 1 , 4 , 12 ]. Many researchers conducted elaborate investigations to find different aspects such as source of error in the application of Fricke dosimetry [ 13 ], the temperature dependence of G (Fe 3+ ) [ 14 ], effect of sulfuric acid concentration in solution containing oxygen [ 15 ], marginal difference in G (Fe 3+ ) value for Co-60 gamma rays and that for high energy X-rays [ 16 ], etc. Olszanski et al [ 17 ] reported various precautionary steps in preparation of reagents, handling of chemicals, instrumentation, development of software to control the read out of Fricke sample and they were successful in bringing uncertainty in measurement between 0.05 and 0.15 %.…”

Section: Introductionmentioning

confidence: 99%

A novel approach towards development of real time chemical dosimetry using pulsating sensor-based instrumentation

Malathi

Sahoo

Praveen

et al. 2013

J Radioanal Nucl Chem

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The paper presents an innovative approach towards development of real time dosimetry using a chemical dosimeter for measurement of absorbed radiation dose in the range between 1 and 400 Gy. Saturated chloroform solution in water, a well known chemical dosimeter, is used to demonstrate the concept of online measurement of radiation dose. The measurement approach involves online monitoring of increase in conductivity of saturated chloroform solution due to progressive build up of traces of highly conducting HCl during exposure to gamma irradiation. A high performance pulsating sensor-based conductivity monitoring instrument has been used to monitor such real time change in conductivity of solution. A relation between conductivity shift and radiation dose has been established using radiochemical yield value (G value) of HCl. The G value of HCl in saturated chloroform dosimeter has been determined using laboratory developed pulsating sensorbased devices. In this connection dose rate of Co-60 gamma chamber was determined using Fricke dosimeter following a simple potentiometric measurement approach developed inhouse besides conventional spectrophotometry. Results obtained from both measurement approaches agreed well. Complete instrumentation package has also been developed to measure real time radiation dose. The proposed real time radiation dosimeter is successfully tested in several measurement campaigns in order to assure its performance prior to its deployment in field.

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Studies in the Radiolysis of Ferrous Sulfate Solutions: II. Effect of Acid Concentration in Solutions Containing Oxygen

Cited by 32 publications

References 7 publications

Iron(III)−Hydrogen Peroxide Reaction: Kinetic Evidence of a Hydroxyl-Mediated Chain Mechanism

Iron(III)−Hydrogen Peroxide Reaction: Kinetic Evidence of a Hydroxyl-Mediated Chain Mechanism

Investigation of the Iron–Peroxo Complex in the Fenton Reaction: Kinetic Indication, Decay Kinetics, and Hydroxyl Radical Yields

A novel approach towards development of real time chemical dosimetry using pulsating sensor-based instrumentation

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