Photocatalytic degradation of soot deposition: Self-cleaning effect on titanium dioxide coated cementitious materials

M. Smits (1) , C.K. Chan , T. Tytgat , B. Craeye , N. Costarramone (2) , Sylvie Lacombe-Lhoste (3) , S. Lenaerts (4)

1 Department of Radiology
2 UT2A - Ultra Traces Analyses Aquitaine
3 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux
4 UA - University of Antwerp

Diesel soot emissions deteriorate the appearance of architectural building materials by soot fouling. This soot deposition devalue the aesthetic value of the building. A solution to counteract this problem is applying titanium dioxide on building materials. TiO2 can provide air-purifying and self-cleaning properties due to its photocatalytic activity. In literature, photocatalytic soot oxidation is observed on glass or silicon substrates. However, degradation of soot by photocatalysis was not yet investigated on cementitious samples (mortar, concrete) although it is one of the most frequently used building materials.In this study, photocatalytic soot oxidation by means of TiO2 coated cementitious samples is addressed. The soot removal capacity of four types of TiO2 layers, coated on mortar samples, is evaluated by means of two detection methods. The first method is based on colorimetric measurements, while the second method uses digital image processing to calculate the area of soot coverage.The experimental data revealed that cementitious materials coated with commercially available TiO2 exhibited self-cleaning properties as it was found that all coated samples were able to remove soot. The P25 coating gave the best soot degradation performance, while the Eoxolit product showed the slowest soot degradation rate. In addition, gas chromatography measurements in a closed chamber experiment with P25 confirmed that complete mineralisation of about 60% of the soot was obtained within 24h since CO2 was the sole observed oxidation product.Due to its realistic approach, this study proves that photocatalytic soot removal on TiO2 coated cementitious surfaces is possible in practice, which is an important step towards the practical application of self-cleaning building materials. © 2013 Elsevier B.V.

Mots clés: Air cleaners; Architectural buildings; Building materials; Buildings; Carbon; Carbon dioxide; Cementitious materials; Cleaning; Coated materials; Colorimetric measurement; degradation; Deposition; Dioxide; Dust; Gas chromatography; Image processing; Materials; Mortar; oxidation; photocatalysis; Photocatalytic activities; Photo catalytic degradation; Photodegradation; Self-cleaning; Self-cleaning effects; Self-cleaning properties; Soot; Titanium; Titanium dioxide

Domaines: Chimie; Catalyse; Matériaux

M. Smits, C.K. Chan, T. Tytgat, B. Craeye, N. Costarramone, et al.. Photocatalytic degradation of soot deposition: Self-cleaning effect on titanium dioxide coated cementitious materials. Chemical Engineering Journal, 2013, 222, pp.411--418. ⟨10.1016/j.cej.2013.02.089⟩. ⟨hal-01499765⟩