Application of response surface methodology for modeling and optimization of Basic Yellow 28 decolorization using sonoelectrochemistry

In this context, a rapid sonoelectrochemical decolorization of aqueous Basic Yellow 28 (BY 28) solutions on a batch reactor using an ultrasound probe (20 kHz) combined with a rectifier was studied. The residual dye was determined by UV-Vis spectrophotometric technique (λ=440 nm). A 25 central composite design (CCD; half-fraction) has been chosen to elucidate the combined effect of five process variables; applied potential, ultrasonic power, pH, electrolyte concentration and temperature. The decolorization percentage (a measure of remediation) and the energy efficiency (a measure of energy saving) were considered responses that were optimized simultaneously using the desirability function. Under the optimum conditions of applied potential (11.15V), ultrasonic power (592.7 W), pH (5), KCl concentration(0.08 mol L-1) and temperature (20.8°C), 99.99% decolorization percent and 0.83 mmolkW-1h-1 energy efficiency was predicted, that was close to obtained experimental results (97.5± 1.1% and 0.75±0.06 mmolkWh-1). The degradation products formed were studied using UV-Vis and HPLC-UV after sonoelectrochemical degradation.