SciELO - Scientific Electronic Library Online

 
vol.62 número2Co2SnO4/CARBON PASTE ELECTRODE AS ELECTROCHEMICAL SENSOR FOR HYDROGEN PEROXIDEABSOLUTE CONFIGURATION OF 13-EPIMULINOLIC ACID índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Revista

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • No hay articulos similaresSimilares en SciELO
  • En proceso de indezaciónSimilares en Google

Compartir


Journal of the Chilean Chemical Society

versión On-line ISSN 0717-9707

Resumen

LEZANA, NICOLE; FERNANDEZ-VIDAL, FRANCISCO; BERRIOS, CRISTHIAN  y  GARRIDO-RAMIREZ, ELIZABETH. ELECTROCHEMICAL AND PHOTO-ELECTROCHEMICAL PROCESSES OF METHYLENE BLUE OXIDATION BY Ti/TiO2 ELECTRODES MODIFIED WITH FE-ALLOPHANE. J. Chil. Chem. Soc. [online]. 2017, vol.62, n.2, pp.3529-3534. ISSN 0717-9707.  http://dx.doi.org/10.4067/S0717-97072017000200021.

This work reports the degradation of methylene blue (MB) on Ti/TiO2 and Ti/TiO2/Fe-allophane electrodes in a pH 3 using 0.1 M Na2SO4 as support electrolyte. SEM micrographs show a homogeneous distribution of TiO2 over the whole electrode surface forming nanotubes and nanopores. Fe-allophane modified electrode shows the formation of large-grains agglomerate on the electrode surface due to allophane, which provides a greater surface area to the electrode due to meso and micropore structures. Preliminary cyclic voltammetry show that Ti/TiO2 has the typical voltammetric response due to Ti(III)/Ti(IV) pair. Diffusional problems were observed through of the film when the electrode is modified with Fe-allophane modifying the quasi-reversible process Ti(III)/Ti(IV). Different kind of methodologies in the degradation process were used: Electrochemistry (EC), Photochemistry (PC), Photoelectrochemistry (PEC) and Adsorption (Ads). These methods were developing to discard any reaction or interaction that is not of interest. On Ti/TiO2 with PC and Ads methodologies was not observed any activity to MB degradation showing that is not photosensitive and that the interaction between this and surface electrode is low. But with EC and PEC degradation to 55% is reached after 3 hours of electrolysis. With Ti/TiO2-Fe-allophane electrodes are observed a higher activity for all methodologies. The PC and Ads methods show that the MB degradation reaches to ~20 % of the initial concentration. As mentioned above, the PC and Ads processes no show degradation on Ti/TiO2, therefore the degradation it only due to the adsorption of MB in/on allophane coat behaving as concentrator matrix. A lower improvement is observed with EC process when is incorporated Ti/TiO2-Fe-allophane is due to the barrier of the electrode surface by oxidation products. With PEC is reached the higher degradation value of ~88 %, showing an improvement of the degradation with the presence of Fe-allophane. The results indicate that the main role of Fe-allophane on the electrode is similar to a concentrator matrix.

Palabras clave : Ti/TiO2; Fe-Allophane; methylene blue; electrochemical and photoelectrochemical oxidation.

        · texto en Inglés     · Inglés ( pdf )

 

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons