Ozone assisted electrocoagulation for decolorization of C.I. Reactive Black 5 in aqueous solution: An investigation of the effect of operational parameters
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 decolorization of the levafix orange textile dye in aqueous solution by electrocoagulation using aluminum sacrificial anode has been investigated. The process performance is analyzed in terms of decolorization efficiency and the important cost-related parameters such as electrode and energy consumptions, as a function of initial pH, conductivity, current density, initial dye concentration and electrolysis time. The present study proves the effectiveness of electrochemical treatment for the textile dye solution. 95% decolorization efficiency may be obtained at suitable operating conditions such as; current density 100 A/m(2), operating time 12 min and initial pH 6.4. The corresponding electrode and energy consumptions during the electrolysis were found to be 1.8 kg Al/kg dye and 35 k Wh/kg dye.Journal of Hazardous Materials 06/2006; 132(2-3):183-8. · 3.93 Impact Factor
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ABSTRACT: Good analytical techniques for the separation and detection of reactive dyes are necessary not only to monitor residual liquors and effluents but also to aid in optimisation of dye synthesis, purification, formulation and application. HPLC, although generally widely employed, often has difficulty in analysing certain reactive dyes, especially the phthalocyanine-based dyes.CE analysis of several gifunctional reactive dyes has been carried out with subsequent activation and hydrolysis reactions for a bis-sulfatoethyl sulfone dye, under different pH and temperature conditions, being monitored. A variety of buffers were investigated; the use of acetonitrile in a micellar buffer system proving to be particularly successful.Journal of Chromatography A. 01/1995; 706:555-562.
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ABSTRACT: Removal of 2-chlorophenol by ultrasonic waves (sonolysis), inorganic catalyst, and a combination of the two processes was tested and compared with each technique. In sonolysis, 2-chlorophenol mostly degraded indirectly in the bulk of solution by the radicals produced in the cavitation process. In catalyst treatment, the removal was performed in the presence of Al2O3, TiO2 and CuO. The highest removal was achieved in the presence of TiO2 for this pollutant. In the combined method an enhancement was observed for the removal of 2-chlorophenol. This could be attributed primarily to the continuous cleaning and chemical activation of the catalyst by acoustic cavitation. The mass transfer between the liquid phase and the catalyst and also the surface area of the catalyst are accelerated by the ultrasonic waves. The removal of 2-chlorophenol was performed under different intensities of irradiation, temperatures and quantities of catalyst. Some experiments were conducted in the presence of a Fenton reagent. In kinetic point of view, the removal of pollutant showed a pseudo-first order behavior. The combined method had a higher rate coefficient than sonolysis and catalyst treatment individually. Under some conditions, the presence of ultrasound has increased the rate coefficient of removal to about 10 times that in the absence of ultrasound.Ultrasonics Sonochemistry 02/2005; 12(1-2):137-41. · 3.52 Impact Factor