Comparison of performances of hydrodynamic cavitation in combined treatments based on hybrid induced advanced Fenton process for degradation of azo-dyes

• Published in: Journal of environmental chemical engineering 2019-06, Vol.7 (3), p.103171, Article 103171
• Main Authors: Innocenzi, V., Prisciandaro, M., Centofanti, M., Vegliò, F.
• Format: Article
• Language: English
• Subjects: Degradation of azo-dyes; Hybrid induced advanced Fenton process; Hydrodynamic cavitation; Venturi tube; Wastewater treatment
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2019.103171

•We study the degradation of azo-dye, methyl orange (MO) by using hydrodynamic cavitation by varying some operating parameters (as inlet pressure).•The degradation of MO was also investigated by using a hybrid method HC- H2O2 – metals.•We determine the energy efficiency of cavitation technique for a comparison with other techniques.•The degradation process in the presence of H2O2 and ion increased of 21 times the efficiency of the HC performed in the absence of additives.•The presence of iron into solution produced a hybrid induced advanced Fenton process. In the present work, the degradation of azo-dyes in aqueous solutions by using hydrodynamic cavitation is performed. Methyl orange was chosen as colorant model pollutant. During the experimental tests, the effect of various operating parameters on the decolourization efficiency was investigated. In the first series of experiments, the hydrodynamic cavitation was optimized in terms of operating inlet pressure and cavitation number to get the maximum decolorization yields of the dye, at the constant temperature of 20 °C and with an initial methyl orange concentration equal to 5 ppm. It was observed that there was an optimum inlet pressure value (4 bar) to get the best decolourization efficiency (about 32%). For the optimal configuration, in correspondence of 4 bar, a first order kinetic equal to 0.0054 min −1 and a value of electrical energy per order EEO of 3793.81 kW h m-3 were calculated. Subsequently, the combined effect of hydrodynamic cavitation and hydrogen peroxide on dye degradation has been studied. The efficiency of the HC-H2O2 system, under optimal conditions, was more than 50% in terms of dye decolourization. Finally, a series of experiments have been performed by combining hydrodynamic cavitation with the addition of hydrogen peroxide and metal ions (iron and nickel) in solution. The dye degradation became greater than 90%; this increase was explained by supposing that an induced advanced Fenton process has been generate thus improving the performance of the entire cavitation system.