The photocatalytic activity evaluation of submicron-sized pigmentary titania using the degradation of Rhodamine B under ultraviolet radiation in a slurry reactor was studied.The effects of titania concentration

Rhodamine B concentration

and wavelength and power of the light source on reaction rate were investigated.The optimal operation conditions for evaluating the photocatalytic activity of pigmentary titania particles were determined.The experimental results showed that the photocatalytic degradation of Rhodamine B by pigmentary titania was an apparent first order reaction.The photocatalytic reaction rate was high under the conditions of a titania concentration of 4 g·L-1

Rhodamine B concentration in the range of 2—10 mg·L-1

and the use of the main emission peak of the light source at 254 nm

which were suitable for evaluating the photocatalytic activity of pigmentary titania.The photocatalytic activity of titania particles with a dense silica coat was measured under these optimized reaction conditions

which showed that this method could be used to evaluate the photocatalytic activity of the pigmentary or film coated titania quantitatively and rapidly.