Experimental design method for removal of blue 5 from aqueous solutions by ozone photocatalyst process

Due to the toxicity effects and endocrine disrupting properties of aromatic compounds, their removal from water and wastewater has gained widespread global attention. In this study, the photocatalytic degradation of blue acid 5 in the presence of titanium dioxide (TiO2) nano-particles and ozone was investigated. A full factorial design consisting of three factors at three levels was used to examine the effect of pH, amount of catalyst and various concentrations of blue acid 5 on the apparent degradation rate constant. The individual effect of TiO2 amount (50, 150 and 250 mg/L), pH (3, 7 and 11) and initial concentration (100, 150 and 200 mg/L) on the apparent degradation rate constant was determined. A regression model was developed to relate the apparent degradation constant to the various factors. The apparent degradation rate constant trend was as follows: O3/UV/TiO2 O3/ TiO2 O3/UV O3 UV/TiO2 . The data indicated no significant interaction between the experimental factors. The lowest activation energy was observed for UV/TiO2 degradation. A maximum degradation rate constant of 0.0138 min−1 was recorded for O3/UV/TiO2 process at pH=11 and a TiO2 amount of 250 mg/L at an initial concentration of 100 mg/L. The response model adequately related the apparent degradation rate constant to the factors within the range of factors under consideration.