Degradation of reactive orange 4 dye using hydrodynamic cavitation based hybrid techniques

Abstract

In the present work, degradation of reactive orange 4 dye (RO4) has been investigated using hydrodynamic cavitation (HC) and in combination with other AOP's. In the hybrid techniques, combination of hydrodynamic cavitation and other oxidizing agents such as H2O2 and ozone have been used to get the enhanced degradation efficiency through HC device. The hydrodynamic cavitation was first optimized in terms of different operating parameters such as operating inlet pressure, cavitation number and pH of the operating medium to get the maximum degradation of RO4. Following the optimization of HC parameters, the degradation of RO4 was carried out using the combination of HC with H2O2 and ozone. It has been found that the efficiency of the HC can be improved significantly by combining it with H2O2 and ozone. The mineralization rate of RO4 increases considerably with 14.67% mineralization taking place using HC alone increases to 31.90% by combining it with H2O2 and further increases to 76.25% through the combination of HC and ozone. The synergetic coefficient of greater than one for the hybrid processes of HC+H2O2 and HC+Ozone has suggested that the combination of HC with other oxidizing agents is better than the individual processes for the degradation of dye effluent containing RO4. The combination of HC with ozone proves to be the most energy efficient method for the degradation of RO4 as compared to HC alone and the hybrid process of HC and H2O2.

Decolorization of Acid Orange 7 by an electric field-assisted modified orifice plate hydrodynamic cavitation system: Optimization of operational parameters

“…However, the efficiency of H 2 O 2 in degrading pollutants can be enhanced significantly if it is used in combination with an HC system. This is because the energy imparted by the collapsing cavities drives the dissociation of H 2 O 2 into Å OH radicals, and supports their subsequent microdiffusion [1,7,34]. Furthermore, the overall performance results showed that a technique combining electric field and HC system had a significant positive effect on the decolorization of AO-7, and reduced reaction time, as shown in Fig.…”

“…In order to highlight the interactive effect of the key parameters (inlet pressure, initial pH, applied voltage, and reaction time) in the EFM-HC, three-dimensional response surfaces derived from Eq. (7) are presented in Fig. 6(A)-(F) with the independent variables being kept constant at the statistically optimized.…”

“…These have involved the use of a variety of methods including electrochemical, electrocoagulation, ultrasonication, chemical oxidation, membrane processes, and other advanced oxidation techniques [3][4][5][6]. Even though lab-scale efforts at decolorization of dye wastewater have been highly successful, these techniques have found less application at pilot and industrial scales due to high cost and due to design constraints that hinder upscaling [7]. Moreover, when sonication is involved, several obstacles hamper the overall removal efficiency of the process.…”

Solvent degradation studies using hydrodynamic cavitation

“…Solvent degradation is rarely reported so far; however, abundant studies are available in the literature for degradation of dyes in wastewaters. Li et al [24] [11]. Thus, although solvent degradation data is not available, it appears that the rate of degradation increases with increasing molar mass with respect to particular class or nature of compounds.…”

Application of hydrodynamic cavitation to improve the biodegradability of mature landfill leachate

“…In recent decades, increasing attention has been devoted to investigating this phenomenon as a tool of disinfection [24,25,26,27,28], cell disruption [29,30] and degradation of various organic compounds, e.g., pharmaceutical residues [31,32], phenols [33], pesticides [34], insecticides [35] and textile dyes [36,37]. However, most studies mainly addressed the process with regard to the synthetic wastewater containing only specific pollutants.…”