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: Background & Aims of the Study: Discharge of textile industry colored wastewater without enough treatment into natural water resources cause serious pollution. Most of the conventional wastewater treatment methods are not effective enough to remove these dyes from wastewater. In this study, efficiency of electrocoagulation process with iron electrodes for treatment of Reactive Yellow 14 dye from synthetic solution has been studied and concluded. Materials & Methods: This experiment was conducted in a batch system with a volume of 2 L that had been equipped with 4 iron electrodes. The effect of operating parameters, such as voltage, time of reaction, initial dye concentration, and interelectrode distance on the dye removal efficiency was investigated. Results: In optimum condition (pH 2, voltage 40 V, electrolysis time 25 min, and interelectrode distance 1 cm), electrocoagulation method was able to remove 99.27% of Reactive Yellow 14 from synthetic solution. Conclusions: Electrocoagulation process by iron electrode is an efficient method for removal of reactive dyes from colored solutionArchives of Hygiene Sciences. 01/2013;
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ABSTRACT: This review discusses the advanced oxidation process (AOP) phenomena in electrocoagulation (EC) process. AOPs have been broadly defined as near ambient temperature treatment processes based on highly reactive radicals, especially the hydroxyl radical ð� OHÞ as the primary oxidant. In principle, as water-containing colloidal particulates, oils, or other contaminants move through the applied electric field, there may be ionisation, electrolysis, hydrolysis, and free-radical formation which may alter the physical and chemical properties of water and contaminants. Further, when the electrochemical reactors operate at a high cell potential and an anodic process occurs in the potential region of water discharge, hydroxyl radicals ð� OHÞ are generated. In order to get more probabilities to have free radicals formation in EC, ultrasound during EC may be very useful as discussed by some authors. Further, EC process at pH less than 3 has more chance to produce hydroxyl radicals formation. Finally, this review concludes that there is no proof of the presence of AOP phenomena in EC process and more research is needed here focusing on free radicals formation.Desalination and water treatment 01/2013; · 0.85 Impact Factor
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ABSTRACT: Various techniques such as physical, chemical, biological, advanced oxidation and electrochemical are used for the treatment of industrial effluent. The commonly used conventional biological treatment processes are time consuming, need large operational area and are not effective for effluent containing toxic elements. Advanced oxidation techniques result in high treatment cost and are generally used to obtain high purity grade water. The chemical coagulation technique is slow and generates large amount of sludge. Electrocoagulation has recently attracted attention as a potential technique for treating industrial effluent due to its versatility and environmental compatibility. This technique uses direct current source between metal electrodes immersed in the effluent, which causes the dissolution of electrode plates into the effluent. The metal ions, at an appropriate pH, can form wide range of coagulated species and metal hydroxides that destabilize and aggregate particles or precipitate and adsorb the dissolved contaminants. Therefore, the objective of the present manuscript is to review the potential of electrocoagulation for the treatment of industrial effluents, mainly removal of dyes from textile effluent.Journal of Environmental Management 07/2013; 128C:949-963. · 3.06 Impact Factor