Ozone assisted electrocoagulation for decolorization of C.I. Reactive Black 5 in aqueous solution: An investigation of the effect of operational parameters

College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, People's Republic of China
Separation and Purification Technology (Impact Factor: 3.07). 06/2007; DOI: 10.1016/j.seppur.2006.12.013

ABSTRACT This study was performed to investigate the variables that influence the efficiency of color removal from a solution containing an azo dye (C.I. Reactive Black 5, abbreviated here as RB5) by the combination of ozonation and electrocoagulation at iron electrodes. Several working parameters, such as initial pH, initial dye concentration, current density, salt (K2SO4) concentration, temperature, ozone flow rate and distance between the electrodes, were studied in an attempt to achieve higher color removal efficiency. The experimental results reveal that the color of RB5 in the aqueous phase was removed effectively. Under the conditions of an initial dye concentration of 100 mg/L, initial pH of 5.5, current density of 10 mA/cm2, salt concentration of 5000 mg/L, temperature of 20 °C, ozone flow rate of 20 mL/min (ozone dose 0.20 g/h), and interelectrode distance of 1 cm, the color-removal efficiency reached 94%, corresponding to a reduction in COD of more than 60%. The energy consumption of the technique was approximately 33 kWh/kg of COD removal.

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    ABSTRACT: The optimum conditions for the electrocoagulation/flotation of two types of anionic dyes (reactive Cibacron Red H-D dye and direct Sulphonil Yellow 5GL dye) have been investigated. The batch agitated vessel consisted of 45° pitched iron paddle anode and a horizontal iron disc cathode which was fixed at the bottom of the vessel. The performance of the vessel was expressed in terms of the percentage of color removal and power consumption calculations. Different parameters have been studied such as: electrolysis time, current density, NaCl concentration, initial dye concentration, initial solution pH, mixing speed (rpm), distance between electrodes, and different anode/cathode combinations. Results revealed that at optimum operating conditions using Fe/Fe electrode combination almost complete color removal of the two investigated dyes has been achieved. Economic studies reveal that removal of one kg of the reactive and direct dye requires 1.87 and 1.5 EGP, respectively. The treatment of real textile effluent at the optimum conditions using the present batch agitated vessel achieved 95.45% color removal and 44% COD reduction.
    Desalination and water treatment 07/2013; 52(34-36):6684-6693. DOI:10.1080/19443994.2013.822635 · 0.99 Impact Factor
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    ABSTRACT: In this research the efficiency of electrochemical treatment process with iron electrodes for treatment of a colored wastewater containing Reactive Red 198 in laboratory scale was studied. The effect of operating parameters such as voltage, reaction time, electrolyte concentration, initial dye concentration and interelectrode distance on the dye removal efficiency have been investigated. The experiments were carried out in a plexiglass reactor. The results indicated that electrochemical process is very efficient mothod for dye removal and in the operational condition able to remove color and COD as high as 99% and 66.6% respectively in 30 minutes at 40 volts and 1 cm interelectrode distance. This study revealed that when the voltage and reaction time increased and interelectrode distance decreased, energy consumption, final pH and dye removal, would be increased. Increasing electrolyte concentration, resulted in decreasing retention time for dye removal. J. Color Sci. Tech. 3(2009), 97-105.© Institute for Color Science and Technology.
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    ABSTRACT: Background and Objectives: Discharge of textile colored wastewater industries without providing enough treatment in water bodies, is harmful for human and aquatic organisms and poses serious damages to the environment. Most of conventional wastewater treatment methods don't have enough efficiency to remove textile dyes from colored wastewater; thus in this research the efficiency of electrocoagulation treatment process with aluminum electrodes for treatment of a synthetic wastewater containing C.I. Reactive Red 198 in batch reactor was studied. Material and Methods: The experiment conducted in a Plexiglas reactor with a working volume of 2L that equipped with 4 aluminum electrodes. The effects of operating parameters such as voltage, time of reaction, initial dye concentration and interelectrode distance on the color removal efficiency, electrical energy consumption and electrode consumption were investigated. Results: in the optimum operational condition electrocoagulation, is able to remove color and COD as high as 99.1 and 84.3% in aluminum electrode in 75 minutes at 20 volt and 2 cm interelectrode distance, respectively. Under this condition, operating cost was 2986 rails per cubic meter of treated wastewater. Increase in the interelectrode distance and initial dye concentration,lead to the decrease in efficiency of dye and COD removal.While as the voltage and time of reaction increased, energy consumption, electrode consumption, final pH and color removal, increased too. Conclusion: electrocoagulation process by aluminum electrode is an efficient and suitable method for reactive dye removal from colored wastewater.