TioCem is a specialized

cement A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel ( aggregate) together. Cement mix ...

with

photocatalytic In chemistry, photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalyzed photolysis, light is absorbed by an adsorbed substrate. In photogenerated catalysis, the photocatalytic activity depends on the abi ...

features, used on the surface of buildings to reduce air pollution caused by exposure of the cement to

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

light (UV).

Technology

Photocatalysis is initiated by

titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insolubl ...

(TiO₂), which is added during the cement's production. Typical properties (i.e. strength) of cement applications (such as concrete) will be added to clean the air around the photocatalytic surface.

Nitrogen dioxide Nitrogen dioxide is a chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year for use primarily in the producti ...

(NO₂) will be particularly abated when daylight activates the photocatalytic surfaces. The chemical process may be summarized as follows: *Titanium dioxide (TiO₂) absorbs energy (UV radiation) and excites

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no kn ...

s (e-) TiO₂ + hν -> TiO₂ + h+ + e- *Oxygen existing in the air (O₂) reacts with electrons (e-), generating super-oxide ions (O₂-) *Super-oxide ions (O₂-) react with hydrogen ions (H+), generating the reactive

hydroxyl In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

radicals (OH•) H₂O + h+ -> H+ + OH- *Nitrogen dioxide (NO₂) reacts with the pollutant remover (OH•) and generates nitrate (NO₃-), which reacts with the cement surface and is dissolved by water. Using materials like TioCem, the abatement of NO₂ could be measured by a test method using the Italian standard UNI 11247, which is being discussed as the basis of a European standard. This method involves test apparatus in which a mixture of air and pollutant flows in a chamber over a test object; the pollutant burden is measured with (and without) exposure to light.Bolte, G. (2009): Innovative building materials - reduction of pollutants with TioCem, ZKG international No. 1-2009, (Volume 62), 63-70
/ref> A defined level of NO₂ abatement is guaranteed by the label “TX Active” (plus an initial) and replication of the test results. Proof of the effective reduction of oxide-of-nitrogen exposure has been furnished under close-to-practical conditions by the PICADA (Photocatalytic Innovative Coverings Applications for Depollution Assessment) Project (supported by the

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been des ...

and other studies.

Applications

Since the photocatalytic effect is needed only on the surface of a building which is exposed to UV, Tiocem is used primarily in the top layer of a two-layer surface. The most effective fields for application are: *Pavement (stones and slabs) *Roofing tiles *Noise and screen barriers *Facades (wall

cladding Cladding is an outer layer of material covering another. It may refer to the following: *Cladding (boiler), the layer of insulation and outer wrapping around a boiler shell *Cladding (construction), materials applied to the exterior of buildings ...

) *Rendering (dry mortar/exterior cement plaster) *Road construction (e.g.

whitetopping Whitetopping is the covering of an existing asphalt pavement with a layer of Portland cement concrete. Whitetopping is divided into types depending on the thickness of the concrete layer and whether the layer is bonded to the asphalt substrate. Unbo ...

) The abatement of NO₂ varies with changing climatic conditions. Field tests were carried out with pavements in

Bergamo Bergamo (; lmo, Bèrghem ; from the proto- Germanic elements *''berg +*heim'', the "mountain home") is a city in the alpine Lombardy region of northern Italy, approximately northeast of Milan, and about from Switzerland, the alpine lakes Como ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

, on the inside walls of a tunnel in

Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...

Ramondo, Valeriana (2007), ''"Galleria Umberto I a Roma"''. ''Progretto & Pubblico'' Dicembre 2007, 48-50 (in Italian). and

stucco Stucco or render is a construction material made of aggregates, a binder, and water. Stucco is applied wet and hardens to a very dense solid. It is used as a decorative coating for walls and ceilings, exterior walls, and as a sculptural and a ...

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

. In all cases, the requirements of TX Active for NO₂ abatement were met.

References

{{Reflist Cement

Technology

Applications

See also

References