Photocatalytic Degradation of Formaldehyde by Diffuser of Solar Light Pipe Coated with TiO2 under Partly Cloudy Conditions in Beijing

Solar light pipe combined with Photocatalysis to depredate formaldehyde under cloudy conditions in summer were tested in Beijing. The solar light pipe used in the experiment is a straight solar light pipe, which is 550mm long, with diameters of 280mmm.Degussa P25 titanium dioxide ("Degussa", Germany) as photocatalyst was coated on the surface of the emitter of the solar light pipe. The test chamber made up of stainless steel is 0.1m(3). The experiment results showed obvious effect on decomposing formaldehyde of solar light pipe combined with Photocatalytic under cloudy conditions. The volume fraction of formaldehyde reduced from 1.0x10(-6) to 0.16x10(-6) during 35min and the value reduced from 1.0x10(-6) to 0.10x10(-6) during 60min under cloudy conditions. The experiment showed that Photocatalytic by the radiations of sunlight under sunny conditions also has good effect for air cleaning.