Parametric optimization of a hybrid cavitation-based fenton process for the degradation of methyl violet 2B in a packed bed reactor

A unique method for treating wastewater containing a commercial dye (Methyl Violet 2B) has been investigated using a hydrodynamic cavitation-based packed bed reactor (HCPBR) which consists of small glass balls. For the first time, the effects of hydrogen peroxide and iron (II) in HCPBR system were examined. In the current study, the Doehlert matrix-based design was used to optimize variables including solution pH, initial concentration of methyl violet 2B, loading of hydrogen peroxide, and iron. The development of cavity bubbles by glass balls and flow-rate-induced jets is the degrading mechanism used in this reactor. It has been observed that the complete removal of methyl violet 2B was obtained at a Fenton ratio of 0.60 and an acidic pH of 2 based on the optimal variables of the Doehlert matrix. Eventually, the pH of the solution (ranging from 1 to 3) was found to be the most important variable in the effective removal of dye. The total required cost was US $ 0.13/L for the HCPBR system based on glass marbles and US $ 0.11/L for orifice-based hydrodynamic cavitation at an optimized Fenton ratio of 0.60 under the acidic pH of 2. Overall, it was observed that HCPBR system based on glass marbles is an effective and alternative technique for the removal of methyl violet 2B dye based on energy economics and ease of fabrication compared to hydrodynamic cavitation.