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TioCem is a specialized cement with photocatalytic features, used on the surface of buildings to reduce air pollution caused by exposure of the cement to ultraviolet light (UV). ==Technology== Photocatalysis is initiated by titanium dioxide (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 (NO2) will be particularly abated when daylight activates the photocatalytic surfaces.〔Bolte, G. (2005), "Photocatalysis in cement-bonded building materials". ''Cement International'' 03/2005 Vol. 3, pp. 92-97.〕 The chemical process may be summarized as follows: *Titanium dioxide (TiO2) absorbs energy (UV radiation) and excites electrons (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 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.〔Martin Hunger, Götz Hüsken, Jos Brouwers, "Photocatalysis applied to concrete products–part 1". ''ZKG international'', No. 8-2008 (Volume 61), 77-85.〕 Using materials like TioCem, the abatement of NO2 could be measured by a test method using the Italian standard UNI 11247, 〔UNI11247, ''Diterminazione dell’attività di degradazione di ossidi di azoto in aria de parte di materiali inirganic fotocatalytici'' (in Italian)〕 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 )〕 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 and other studies.〔(PICADA Project ) Retrieved 2012-04-12.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tiocem」の詳細全文を読む スポンサード リンク
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