CFD simulation and experimental investigation of a novel swirling jet induced cavitation reactor for methyl orange decolorization

In this work, a novel design of a swirling jet-induced cavitation reactor (SJCR) was introduced, simulated by computational fluid dynamics (CFD), constructed, and implemented to decolorize the methyl orange (MO) dye in a pilot scale setup. According to the simulation results, the maximum velocity magnitude 41.4 m s^-1 was calculated at inlet pressure 1.0 MPa and the corresponding mass of vapor phase was 55.60 × 10^-3 mg. In the experimental results section, inlet pressure (0.4-0.8 MPa), bulk temperature (30-50 °C), initial pH (3- 9), initial MO concentration (5-20 mg L^-1), and Fenton's reagent (50 mg L^-1 for both Fe and H₂O₂) effects on the decolorization process were studied. In the optimum operating conditions (inlet pressure 0.8 MPa, bulk temperature 40 °C, initial pH 3, and initial MO concentration 10 mg L^-1), the mass of the decolorized MO without Fenton was about 381 mg after 180 min process time and consumed electrical energy was 33.1 Wh mg^-1. By adding Fenton's reagent in the optimum operating conditions, the decolorization process was completely done in less than 1 min by consuming 0.2 Wh mg^-1 of electrical energy and synergetic index (SI) of 2.2. According to the kinetic analysis, MO decolorization followed first-order reaction kinetics. Considering the high volume of the treated solution (about 58 L) compared to similar works, the decolorized mass of MO, and consumed electrical energy, the high performance of this novel SJCR was approved.