Photocatalytic activation of gypsum cements

Photocatalytic activity of gypsum cements that are based on the building plaster blend and synthetic calcium sulfate and contain 2–10 wt % titanium dioxide of anatase modification was studied. The decomposition rate of the model contaminant (Rhodamine C) on the surface of a plaster blend containing 2 wt %TiO2 becomes seven times higher under exposure to a full spectrum of a UV lamp, and 29 times higher under UV-A irradiation at λ > 320 nm. It was found that there are two competing processes (photocatalysis and direct photolysis), which affect the decomposition rate of Rhodamine C on the surface of the cements, depending on the UV irradiation spectrum.