Background: Sonolysis a method that uses advanced oxidation processes (AOPs), which remove organic contaminants without producing secondary waste.
Objectives: The aim of this study was to develop an empirical kinetics model to predict apseudo-first order rate constant (k_ap) of sonochemical degradation of malachite green (MG). Then, this model was used to estimate the required electrical energy per order (E_EO) at various operational conditions.
Materials and Methods: 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.
Results: 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 (k_ap) 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.
Conclusions: 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 E_EO 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, E_EO is very sensitive to the mentioned operational parameters.