INVESTIGADORES
CALVO Ernesto Julio
artículos
Título:
ELECTROKINETICS OF THE REDUCTION OF CHROMIUM(VI) IONS
Autor/es:
PALLOTA, C.D.; GONNET, R.; CALVO, E.J.
Revista:
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
Editorial:
Elsevier
Referencias:
Lugar: Amsterdam; Año: 1988 vol. 241 p. 265 - 279
ISSN:
0022-0728
Resumen:
The electrokmetics of chromium-modified passive iron electrodes in alkaline chromate solutions are
reported. Cyclic voltammetric studies at different pHs, chromate concentrations and temperatures have
shown two different types of pseudocapacitive behaviour: the reductive precipitation of hydrous Cr(II1)
species on the top of the iron passive layer and redox transformations of chromium ions entrapped in the
passive film matrix.
The latter process has been analysed in terms of a thin layer redox-modified electrode model. A
simple kmetic behaviour for the multi-electron Cr(VI)/Cr(III) reduction with a Cr(VI)/Cr(V) rate-determining
step involving a protonanon step is apparent with a Tafel-type temperature dependence.
The electrochemical results are discussed in connection with XPS chromium concentration-depth
profiles in the modified surface matrix.