April 2011
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10 Citations
A system consisting of TiO2 and cement has recently been studied within the framework of a strategy for alleviating environmental pollution through the use of construction materials containing photocatalysts. This technology for the photocatalytic degradation of organic pollutants is aimed at maintaining the aesthetic characteristics of concrete structures, particularly those based on white cement. The main reason for the discoloration of cementitious materials is the accumulation of coloured organic compounds on their surfaces (see also Sect. 3.2). Suitable amounts of TiO2 have been introduced into cement mixes to render the surfaces of the resulting structures photocatalytically active. In order to verify the photocatalysis, experiments focusing on the oxidation of several kinds of aromatic organic compounds have been carried out. For instance, white cement disks have been impregnated with a phenanthroquinone solution (0.1 mg/cm2), yielding homogeneously yellow surfaces. Accelerated irradiation tests were then performed with a solar simulator (100 h of irradiation, corresponding to 1 year of sunlight). A rapid restoration of the clean surface was obtained.