The effect of UV radiation absorption of cationic and anionic dye solutions on their photocatalytic degradation in the presence TiO2

The aim of the study was to examine the correlation between the absorbance of various cationic and anionic dye solutions exposed to UV radiation and their photocatalytic degradation in solution. The dye solutions were illuminated with UV radiation in the presence of a TiO2 aqueous suspension. Photodegradation rate constant and adsorption efficiency of dyes were determined using spectrophotometric methods.Only cationic dyes can be adsorbed on the surface of the photocatalyst; simultaneously, their photocatalytic degradation is faster than the degradation of anionic dyes.The change of the nature of the dye particle from inert to cationic causes intensification of its adsorption and acceleration of photodegradation. There is a linear correlation between the absorbance of the illuminated dye solution and the photodegradation rate constant.