Study of surface reactions of the Fe/Fe2+ heterogeneous isotope-exchange system with a radioactive indicator (Fe-59)

Kónya, József

doi:10.1016/s0022-0728(77)80230-1

Cited by 5 publications

(1 citation statement)

References 20 publications

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“…, curve a) results in a lower apparent rate constant for the reduction of Fe(H 2 O) 6 3+ . A similar situation has also been noted elsewhere and was attributed to interfacial precipitation of Fe hydroxide(s) (Fe(III), K sp = 4 × 10 -38 ; Fe(II), K sp = 8 × 10 -16 at 298 K 46 ) due to the consumption of H + in the double layer. This difficulty may be avoided by either employing a rapid scan rate to prevent accumulation of the precipitate (curves c and d) or commencing the cathodic scan at the equilibrium potential ( E eq ≈ +0.5 V for equimolar Fe(II/III)).…”

Section: Resultssupporting

confidence: 79%

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles

Madigan

Coury

1997

Anal. Chem.

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Heterogeneous electron transfer kinetics for reduction of Fe(H 2 O) 6 3+ at Pt electrodes in the presence of equimolarFe(H 2 O) 6 2+ in noncoordinating 1.0 M HClO 4 have been studied during irradiation with high-intensity ultrasound at 20 kHz both in the presence and in the absence of small solid particles. Increases in heterogeneous rate constants have been measured during sonication in the presence of 1-µm particles of Al 2 O 3 . During sonication, particles collide with the electrode surface, generating heat and enhancing kinetic rates relative to those determined for sonication in the absence of particles. Control experiments (in the absence of ultrasound) were conducted with a rotating disk electrode (RDE). Rate constants from charge transfer resistance measurements within (0.025 V of the equilibrium potential obtained by RDE, sonication, and sonication with 16.7 g of Al 2 O 3 per liter of solution were (3.4 ( 0.1) × 10 -4 , (4.2 ( 0.5) × 10 -4 , and (20 ( 2) × 10 -4 cm/s, respectively. By comparison, Tafel plots corrected for mass transport effects gave rate constants (RDE, sonication, and sonication with Al 2 O 3 ) of (4.4 ( 0.2) × 10 -4 , (6 ( 1) × 10 -4 , and (15 ( 5) × 10 -4 cm/s, respectively. Additional studies indicated that no increases in electrode area or rate constants were measurable postsonication; thus, rate enhancements are attributed to thermal effects (cavitation and collisions). Similar enhancements were also found for Fe(CN) 6 3-reduction in the presence of equimolar Fe(CN) 6 4-. Nonsonication, variable-temperature studies of Fe(H 2 O) 6 2+/3+ gave activation energies for the kinematic viscosity, Fe(H 2 O) 6 3+ diffusion coefficient, and standard heterogeneous rate constant of 15.8, 14.9, and 12.1 kJ/mol, respectively. From the Arrhenius relationship, effective temperatures at the electrode surface during sonication of a solution held at 273 K were found to be (282 ( 5) K without Al 2 O 3 and (410 ( 10) K with 16.7 g of Al 2 O 3 per liter of solution. The addition of larger quantities of Al 2 O 3 produced even greater effects.

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Section: Resultssupporting

confidence: 79%

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles

Madigan

Coury

1997

Anal. Chem.

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Physicochemical Application of Radiotracer Methods

Kónya

Nagy

2012

Nuclear and Radiochemistry

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Physicochemical Application of Radiotracer Methods

Kónya

Nagy

2018

Nuclear and Radiochemistry

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Study of surface reactions of the Fe/Fe2+ heterogeneous isotope-exchange system with a radioactive indicator (Fe-59)

Cited by 5 publications

References 20 publications

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles

Physicochemical Application of Radiotracer Methods

Physicochemical Application of Radiotracer Methods

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Study of surface reactions of the Fe/Fe2+ heterogeneous isotope-exchange system with a radioactive indicator (Fe-59)

Cited by 5 publications

References 20 publications

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H2O)62+/3+during Sonication of Suspensions of Alumina Particles

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H2O)62+/3+during Sonication of Suspensions of Alumina Particles

Physicochemical Application of Radiotracer Methods

Physicochemical Application of Radiotracer Methods

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Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles

Measurement of Heterogeneous Electron Transfer Rate Constants for Fe(H₂O)₆^2+/3+during Sonication of Suspensions of Alumina Particles