Application of response surface methodology and central composite design for the optimization of textile dye degradation by wet air oxidation

Background: The present study is aimed at investigating the degradation of azo dye solution of AR 274 by wet air oxidation conditions. The central composite design matrix and response surface methodology were applied in designing the experiments to evaluate the interactive effects of the three most important operating variables. Thus, the interactive effects of oxygen pressure (3.0 to 5.0 MPa), temperature (100 degrees C to 250 degrees C), and time (30 to 90 min) on the degradation of dye were investigated. Results: The predicted values were found to be in good agreement with the experimental values (R-2 = 0.9981 and Adj-R-2 = 0.9965), which define the propriety of the model and the achievement of CCD in the optimization of WAO process. Conclusions: Intermediates of dye degradation were detected by GC-MS, the possible degradation mechanism for the WAO of dye was discussed, and the probable degradation pathway was deduced.