Degradation of naproxen by combination of Fenton reagent and ultrasound irradiation: optimization using response surface methodology.

A central composite factorial design methodology was employed to optimize the degradation of naproxen (NPX) by the combination of Fenton reagent and ultrasound (US) irradiation. In this study, the variables considered for the process optimization were the hydrogen peroxide, ferrous ion and NPX initial concentrations, while ultrasonic power amplitude was adjusted at 90% and initial pH was 3. An appropriate quadratic model was developed in order to plot the response surface and contour curves. Optimum dosage of Fenton reagent for NPX removal was found to be hydrogen peroxide concentration = 9.98 mmol L⁻¹, ferrous ion concentration = 4.83 mg L⁻¹ while NPX concentration was equal to 20 mg L⁻¹. A degradation efficiency of 100% was achieved within 10 min under US.