Development of an Empirical Kinetics Model for Sono-Degradation of Malachite Green: Evaluation of Electrical Energy Per Order

Sonolysis a method that uses advanced oxidation processes (AOPs), which remove organic contaminants without producing secondary waste. The aim of this study was to develop an empirical kinetics model to predict apseudo-first order rate constant (kap) of sonochemical degradation of malachite green (MG). Then, this model was used to estimate the required electrical energy per order (EEO) at various operational conditions. An ultrasonic bath with the operating frequency of 35 kHz and an output power of 170 W was used for sonochemical degradation of MG. The MG concentration was determined using a spectrophotometer at 617 nm. The experimental data showed that the degradation of MG in this process obeyed pseudo-first order kinetics. Using nonlinear regression analysis a model was developed for apseudo-first order constant (kap) of the MG sono-degradation as a function of operational parameters, including initial concentration of MG (5 - 10 m gL-1), temperature (294 - 307 K), power density (0.049 - 0.163 W mL-1) and mechanical agitation (75 - 400 rpm), as shown in the Equation 3. The present research demonstrated that the ultrasonic (US) process can be utilized as an effective and simple method for treatment of MG dye in an aqueous solution. Moreover, the EEO is directly proportional to the MG concentration and power density and inversely proportional to temperature and mechanical agitation, which can be predicted by the obtained empirical kinetics model. Consequently, EEO is very sensitive to the mentioned operational parameters.