Production and characterization of photocatalitic PEO coatings containing TiO2 powders recovered from wastes

In this work, the possibility of incorporating TiO2 titanium dioxide particles, derived from recycling process of photovoltaic panels, into PEO coatings was investigated. These particles constitute the main filler of the polymer constituting the rear part of the panels and are characterized by possessing photocatalytic properties. The particles were added in different quantities to the electrolyte (a basic solution containing sodium silicate). The incorporation into the PEO coating, produced on an aluminium alloy 1050, and the possibility of conferring photocatalytic properties to the surface of the samples were studied. The different samples were first characterized by optical microscope analysis and by SEM and XRD and, from the point of view of corrosion resistance by means of potentio-dynamic tests. The photocatalytic properties of the particles and, subsequently, of the samples were evaluated by measuring, with a UV-visible spectrophotometer, the degradation of aqueous solutions of methylene blue with exposure to a UV lamp. The particles have been successfully incorporated into the coating and their presence does not alter the corrosion properties, which are improved compared to the uncoated sample. The particles, initially composed of a mixture of rutile and anatase, are instead composed only of rutile after incorporation, due to the locally very high temperatures that can occur during the PEO process. In the samples obtained with higher quantities of titanium dioxide particles (60 and 80 g / l) a significant photocatalytic effect is observed with a significant reduction of methylene blue.