Air purification by means of heterogeneous photocatalysis

The heterogeneous photocatalysis relies on the activation of a half-conductor. The most often used is TiO2, with radiations of energy at least equal to the ones of the width of the forbidden band.The electronic changes due to that activation lead, in the presence of air, to the creation of oxygenated radicals. Those radicals attack the adsorbed organic compounds and degrade them. Starting from evaluations made with a laboratory photoreactor, this paper shows that photocatalysis is an appropriate method to purify air in domestic buildings (or other confined spaces). Otherwise, good results have been obtained with the photocatalytic treatment of air that was used to extract the lightly chloric aliphatic hydrocarbons from grounds or water.