A dye-methylene blue (MB)-degraded by hydrodynamic cavitation (HC) and combined with other oxidants

As a kind of AOPs, hydrodynamic cavitation (HC) has the characteristics of energy savings and easy amplification. It is of great significance to study the degradation of dye molecules with HC, due to the toxicity, chroma and difficult biodegradation of dyes. In the present work, the HC treatment of methylene blue (MB) was investigated, and the effects of inlet pressure, solution pH, and initial concentration on the degradation of MB dye were explored. The maximum degradation rate of MB was obtained at 0.3 MPa, pH = 2, and an initial concentration of 10 mg/L. The combination of Na2S2O8 or O-3 with HC were also conducted to explore their synergistic effect. The results indicated that the degradation performance of introducing ozone is better that of adding Na2S2O8. When the amount of O-3 gas was 0.12 g/h, the MB degradation rate was over 99%, and the synergy index was 3.58. The intermediate products in the MB disintegration process were detected based on LC-MS, and the reaction mechanism and path of MB were proposed.

Automated summary

As a kind of AOPs, hydrodynamic cavitation (HC) is an energy-saving and easily scalable technology. Studying the degradation of dye molecules using HC is of great significance due to the toxicity, chroma, and difficult biodegradation of dyes. In this study, the HC treatment of methylene blue (MB) was investigated, and the effects of inlet pressure, solution pH, and initial concentration on MB degradation were explored. The results showed that introducing ozone had better degradation performance, and the reaction mechanism and path of MB were proposed based on the detection of intermediate products using LC-MS.