Photo-assisted electrochemical copper removal from cyanide solutions using porous TiO sub(2) thin film photo-anodes

• Published in: Materials research (São Carlos, São Paulo, Brazil) Vol. 17; no. 1; pp. 69 - 77
• Main Authors: RAMIREZ-SANTOS, Alvaro A, ACEVEDO-PENA, Prospero, CORDOBA, Elcy M
• Format: Journal Article
• Language: English; Portuguese; Spanish
• Published: 01-02-2014
• Subjects: ANODES; COATINGS; Copper; CRACKS; Cyanides; Dip coatings; HEAT TREATING; Heat treatment; MICA; Polyethylene glycol; Reduction; THIN FILMS; TITANIUM DIOXIDE
• ISSN: 1516-1439
• DOI: 10.1590/S1516-14392013005000150

TiO sub(2) porous films were prepared on ITO coated glass slides by the sol-gel dip-coating method assisted with Polyethylene glycol (PEG). The films were used as photo-anodes in the photo-assisted electrolytic removal of cuprous ions in cyanide media. These were characterized by SEM, UV-Visible spectroscopy and XRD. The PEG modified films were free of cracks and developed a porous structure after heat treatment at 500 [degrees]C, due to the thermal decomposition of the structure associated PEG. It was demonstrated that the photo-assisted electrochemical reduction of copper is promoted by the use of modified TiO sub(2) films as photo-anodes, thanks to the greater surface area given by the PEG decomposition. However, the film thickness was found to be a critical factor in the process, to such an extent that films composed of 5 layers were completely inefficient, meaning that despite the open porosity, multilayered films acted as a barrier within the photo-electrolytic process.