Photocatalytic products, a new idea for the building industry
The photocatalytic products are a today’s idea, and play an important role to reduce pollution thanks to their technology that allows them to be used in a number of cases. Tiles, concretes, paints and floor coverings are only some examples.
These materials are stirring a strong interest all over Europe, especially in the building industry. These materials show their best when applied on “traditional” surfaces: they are self cleaning, absorb some polluting agents in the air and perform an antibacterial effect, transforming the surfaces on which they are applied into multifunctional elements.
They work thanks to a natural phenomenon, where a substance called photocatalyst modifies the chemical reaction through the light. This reaction accelerates the oxidation process, helping the polluting agents to decompose. This polluting agents are transformed into harmless water soluble inorganic salts. Here the nitric oxide (NOx), the particulate matter (PM10), or the VOC (Volatile Organic Compounds) turn into harmless substances, both for men and environment, like sodium nitrate (NaNO3), sodium carbonate (CaNO3) or calcium carbonate (CaCO3). One of the most used catalyst is a particular mineral form of the titanium dioxide (TiO2), the anatase: it combines the anti-polluting effect with the antibacterial effect.
This materials can be used both in closed and open spaces. The presence of an artificial or natural light source is the only essential element for this process to take place. Their use in closed spaces can be an opportunity to use their antibacterial characteristics: thanks to the acceleration in the oxidation process, the photocatalytic materials remove the main bacterial strains, starting a self-cleaning and preservation of their characteristics process. This means that there are new scenarios for their use in hospitals, and in other special environments with controlled biological contamination. The use in public environments like canteens, hotels and restaurants will also be experimented.
The experimentation of photocatalytic products from the titanium dioxide is going towards the development of a film, that can be used in vertical and horizontal surfaces, thanks to its transparence. In the future, windows façades, helped by the sun and by this components, will clean the air, reducing the pollution levels, will clean themselves and will eliminate the misting. This is important for the maintenance of a high building, with surfaces difficult to reach.
The most used surface for this photocatalysis is the concrete. The porosity helps to maximize the effects of the photocatalytic process, with a wider surface hit by the sunlight and performing oxidation, proportionally increasing the absorption of toxic elements.
This products are also widely used in the pavements, for places with high traffic and pollution. Here the photocatalytic properties are integrated with the sound-absorbing panels, for a solution with two different functions: protection from sound and environmental pollution. A covering with photocatalytic tiles has been made, and thanks to the titanium dioxide it absorbs toxic matter in the atmosphere, dispersing it in the soil as not toxic salts.
According to the CNR researches, 1 square meters of photocatalytic materials can clean up to 90% of 1 cubic meter of air in only 45 seconds. Proportionally, a 200 square meters surface like a covering, could in a year absorb the polluting agents caused by a medium-size car or by two boilers used for the heating of a residential building. This technologies, together with the photovoltaic panels can help a real transformation of the cities, increasing the quality of life and reducing air pollution.