The adsorption and photocatalytic efficiency of several TiO2 suspended catalysts were compared to see how well they could degrade the organic pollutant anthraquinone dye Reactive Blue 2 (RB2). The adsorption of RB2 on catalysts follows the Langmuir model and adsorption capacity's influence on degradation performance has been established. Correlations between degradation kinetics and the amount of dye adsorbed (qads) were then determined. The expected correlation between specific surface and qmax was verified. The addition of sulphate ions in the case of catalysts Degussa P25 and TiO2-Ishihara ST01 was found to inhibit adsorption of RB2 on the TiO2 surfaces. The hindrance of adsorption in acidic conditions improved the efficiency of the photocatalytic degradation of ST01. No adsorption was observed in alkaline pH and the photodegradation kinetic was generally higher in this condition except for that seen in photocatalysts with a low recombination rate.
Keywords: adsorption, anthraquinone dye, Langmuir model, photocatalytic degradation, recombination rate