Air pollution has a negative impact for citizens' health, reducing human life expectancy by more than 8
months on average, and by more than 2 years in the most polluted areas [2012, EEA, Air quality in
In this context, photocatalytic surfaces might play a major role in cleaning indoor and outdoor environments.
Photocatalysis is a chemical reaction mediated by light, humidity and by the so-called photocatalyst (e.g. TiO2), and it is important for the oxidation of pollutants, biological toxic agents, and volatile organic molecules [1995, A.L. Linsebigler et al., Chem. Rev., 95 (3)]. For such reason, tiles coated with a photocatalyst represent very valuable products. GranitiFiandre (GF), global leader in porcelain tiles, developed state-of-the-art photocatalytic tiles called Active Clean Air & Antibacterial Ceramics™ (hereinafter named Active) able to effectively remove polluting and biochemical agents, and volatile organic substances.
The Active ceramic tiles coating process consists in spraying a mixture of titania powder (~1µm), water and silica-based additives over the tiles' surface, and in a heating cycle (680°C).
Subsequently, the tiles' surface are brushed and washed with water, in order to remove titania particles in excess, and finally the homogeneity of the surface is assessed. Such process presents some drawbacks, as it involves the consumption of large quantity of water (260 g/m2), energy (0,041 kWh/m2), and the 70% of titania is lost from the input to the final deposition.
The DIGITALIFE project will overcome such drawbacks by using digital printing technology, thus representing an important paradigm shift with respect to the state-of-the-art TiO2 coating processes.
The project will firstly demonstrate a technology based on suitably designed print heads using an ink based on solvents, TiO2, and additives (Si-based powders to allow the surface vitrification), able to coat a wide range of tiles surfaces (up to 1,5x3m).
This will allow achieving 12% energy efficiency, almost 100% water saving and a consistent reduction of TiO2 waste (at least 50%).
Secondly, the use of an innovative water-based ink instead of a solvent-based ink will be demonstrated, further reducing the process' environmental impact.
The green and sustainable DIGITALIFE solution will be validated and the project results widely disseminated in order to raise awareness on sustainable manufacturing, and on the positive environmental impact of eco-active tiles.