Study of the effect of operative conditions on the decolourization of azo dye solutions by using hydrodynamic cavitation at the lab scale

In the present study, the potentiality of hydrodynamic cavitation (HC) for the degradation of methyl orange from synthetic aqueous solutions is presented. Hydrodynamic cavitation was set up at laboratory scale using a Venturi tube. Solutions of methyl orange (MO) were subjected to cavitation in order to investigate the efficiency and the potential of this technique for azo dye degradation. Moreover, a HC/H2O2/TiO2 hybrid system was tested with the aim to verify its potential positive impact on the decolourization process and define the best conditions, among those investigated, to remove azo dye from synthetic solutions. The results obtained in this study showed that the maximum efficiency was close to 30% using a Venturi tube at an operating pressure of 400 kPa. The presence of additives, such as titanium dioxide and hydrogen peroxide, increased the performance of the degradation process to slightly above 70%.