Modeling and optimizing Acid Orange 142 degradation in aqueous solution by non-thermal plasma

The effects of the high voltage electrode material, initial pH of the solution, initial concentration of Fe2+, and time of plasma treatment on the efficiency of Acid Orange 142 (AO142) degradation were studied and evaluated. Furthermore, based on the Box-Behnken response surface methodology (BBD-RSM), a model between response (decolorization efficiency %) and influencing factors was proposed to estimate the interactive effects and optimize the process conditions. The proposed model was adequate with an R2 of 0.8005 which is in reasonable agreement with the R2adj of 0.9307. According to the model, the optimum conditions were steel as a high voltage electrode, an initial pH 3.0, an initial Fe2+ concentration 0.9 mM, and 20 min time of treatment to obtain a decolorization efficiency of 95.05%. In addition, the analytical results of UV-Vis, FT-IR, TOC and GC-MS indicated the degradation of the dye molecule.