Photocatalytic degradation and absorption kinetics of cibacron brilliant yellow 3G-P by nanosized ZnO catalyst under simulated solar light

Abstract

The photocatalytic degradation process and absorption kinetics of cibacron brilliant yellow 3G-P dye aqueous solution under UV–Vis light were investigated by using nanosized ZnO as a photocatalyst. The influencing parameters of dye degradation during photocatalysis, such as initial dye concentration, catalyst dosage, initial pH value and irradiation intensity, were investigated in detail. The dye solutions with concentrations < 100 ppm were ∼98% decolorized after 60 min of UV–Vis light irradiation. The dye degradation was enhanced at original pH, indicating no requirement of pH value adjustments in process. The degradation of the dye at 200 ppm was only 52% at irradiation intensity of 7.7 µW/cm2 after 60 min, but above 75% degradation was achieved at 14.8 µW/cm2. The photodegredation kinetics of cibacron brilliant yellow 3G-P followed the Langmuir–Hinshelwood model. From the kinetic model analysis, the adsorption constant increased with increasing irradiation intensity but decreased with increasing initial dye concentration. The photodegradation and adsorption rate were relatively high for cibacron brilliant yellow 3G-P, but the maximum quantity of absorbance on ZnO surface was only 45 µmol/g.