Assessment of Photocatalytic Nano-TiO2 Mortars’ Behavior When Exposed to Simulated Indoor Conditions of Glazed Buildings

Abstract

The application of nano-TiO2 as a photocatalytic agent in buildings’ internal surfaces has recently attracted attention to mitigate microorganism growth, soiling, and contamination in indoor environments. This work aimed at comparing the Rhodamine B (RhB) dye degradation efficiency of three different mortar compositions subjected to simulated internal radiation, in which nano-TiO2 (10 wt% of binder mass) was dispersed by ultrasonic and mechanical methods. Mortar specimens were produced with white Portland cement, hydrated lime, sand, and water in different volume proportions of 1:1:6 (cement:lime:sand), 1:3 (cement:sand), and 1:4 (cement:sand). The first stage of the research evaluated samples exposed to the natural outdoor environment and proved the efficiency of specimens’ photoactivity when covered by a glass layer. The second and principal phase of the study simulated indoor conditions in glazed buildings through artificial weathering in which the composition of 1:1:6 was mechanically dispersed and exhibited the highest global color change (ΔE) values for RhB staining. The main finding of the study was that the mortars exposed to simulated indoor conditions presented high ΔE grades, classified as easily perceived by the human eye. This demonstrates the photocatalytic efficiency in an internal building environment that receives radiation through a glass surface.

The Effectiveness of Spraying nTiO2 on Coating Mortars in Historical Buildings Aimed at Reducing Fungal Growth

“…According to those authors, the process involving microorganisms happens through the competition between the recombination (in nanoseconds) of photoexcited charge carriers, electrons and holes, and their transference to the interior of the cells. TiO 2 has aroused interest in its application in the construction industry due to its selfcleaning, air depolluting, and antimicrobial properties in cement-based materials [30,31]. Jędrzejczak et al [32] added titanium oxide, especially the anatase variety, to a cementitious matrix substrate, observing an improvement in the antibacterial properties of the composite.…”