Influence of pigments on the photoactivity of TiO2-containing colored mortars compared with white mortars and sol-gel TiO2 application route
M.V. Diamanti, B. Del Curto, M. Ormellese, MP. Pedeferri
Politecnico di Milano, IT
Keywords: photocatalytic mortar, pigment, self-cleaning, titanium dioxide
Abstract:In previous works, TiO2-containing commercial mortars were proved to show photoactivated properties due to the well-known semiconducting structure of titanium dioxide in anatase form. Anatase was added to white mortars in form of suspension or nanometric powder; their efficiency in degrading polluting compounds, as well as in limiting contaminants adhesion comparing to conventional materials surfaces (self-cleaning), were analyzed. In this study the possible influence of the presence of pigments in the mortar was investigated: photodegradation tests of liquid and volatile organic compounds were performed on mortars containing different pigments (iron oxides conferring yellow, red and grey colorings). To evaluate the self-cleaning properties colored samples were exposed to a polluted urban atmosphere for several months and color changes were monitored. Results showed a decreased photocatalytic activity of colored mortars with respect to white ones; less influence was detected on self-cleaning performances. Finally, the possibility to add TiO2 to construction materials as a surface covering by sol-gel, instead of as bulk addition, was considered. This experimental procedure is still under investigation, yet it offers interesting scenarios both from a performance and an economical point of view.