comparison of homogeneous and heterogeneous fenton and sono-fenton decolorization of titan yellow: doehlert optimization, response surface methodology, and synergic effects study

in this work, four fenton processes were used for the decolorization of titan yellow. experimental conditions such as concentration of h2o2, ph, time, zero-valent iron dose, and concentration of fe^2+ were optimized by doehlert experimental design and response surface models. in the absence of ultrasonic waves, the application of zero-valent iron had an intense effect on decolorization percent (95% for heterogeneous fenton with respect to 18% for classical fenton). the optimum conditions were (0.0054m h2o2, 0.031g/l fe^2+, ph 2.5 and reaction time 47 min) and (0.0013m h2o2, 0.194g/l zero-valent iron, ph 2.5, and reaction time 10 min) for homogeneous and heterogeneous fenton processes, respectively. both homogeneous and heterogeneous sono-fenton processes reached to decolorization percent of 100%. the optimum ph was 2.5 for the two processes. the optimum conditions for homogeneous and heterogeneous sono-fenton processes were (0.0035m h2o2, 0.0037g/l fe^2+, and reaction time 30 min) and (0.0014m h2o2, 0.4g/l zero-valent iron, and reaction time 10 min), respectively.