|Keywords||Advanced Oxidation Processes, Reactive azodyes, UV/ClO2, Effluents, Decolourization, ADMI, IPPC|
|Abstract||Azo dyes are used in a large number of industries (fabric, food, pharmaceutical, paper and printing, leather and cosmetics) and are an important environmental problem. Many of these colors are released into the environment through the wastewater treatment plants. It is estimated that about 15% of the total global production of colors is lost during their synthesis and management. Therefore approximately 128 tons of dyes enter the environment per day, mainly due to the partial color attachment to the substrate during the painting procedure, and due to the loss of a great percentage 10–20% during their synthesis. Azo dyes are the greatest group of colors, which is subdivided into four classes, depending on the number of nitro groups contained in their molecule. Azo dyes are the greatest class of organic dyes as recorded in the Colour Index 4th ed. (60-70% of the total number) and have been regulated in the framework of the Directive 96/61/EEC/24-9-96 for Integrated Pollution Prevention and Control (IPPC). The aim of the present work is to determine the optimum treatment for the color reduction to the limit of 300ADMI and to evaluate the effectiveness of the use of ultraviolet irradiation (UV) in combination with chlorine dioxide (ClO2), for the color removal from three azo reactive dyes and from their wastewater mixture. For the reduction of the concentrations of reactive azo-dyes, the AOP UV/ClO2 was applied, and the main factors affecting them were investigated. The colors investigated are the commercial reactive azo-dyes Red ME 3BS, Blue ME 2GS and Green (Mixture of: Yellow ME 3RS - Red ME 3BS & Blue ME 2GS). An effluents mixture of these colors was also studied. Dye solutions were dosed with selected concentrations of ClO2 and pumped through the UV unit at varying rates to provide various UV contact times. Once the appropriate UV contact times had been achieved, samples were taken from the output and the ADMI was evaluated with spectrophotometric method of determination of intensity of colour.The treatment with UV/ClO2, removed the effluents and red and blue colors to the value of 300 ADMI in 1 minute. One explanation for the increased rate of reduction is that the oxidant is largely consumed within the first minute and the remaining decolourization is a result of UV exposure. The increased oxidizing strength of ClO2 may have provided additional decolourization during the remaining time of UV exposure. However the green color was more resistant to the oxidation, the limit of 300 ADMI was not achieved during the available time.|
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|Name||Affiliation||Home page||Total pubs|
|Karali IG||University of the Aegean, Faculty of the Environment, Department of Environmental Studies, University Hill, 81100 Mytilene, Lesvos, Greecefirstname.lastname@example.org||1|
|Lekkas TD||University of the Aegean, Dept. of Environmental Studies||http://email@example.com||71|
|Nikolaou AD||Department of Marine Sciences, University of the Aegean, University Hill, 81100 Mytilene, Greecefirstname.lastname@example.org||44|
|Rousias IA||Technological Education Institute of Piraeus, Faculty of Technological Applications, Department of Chemistry and Quality Control of Materials, P.Ralli & Thivon 250, 12244 Aigaleo, Attica Greece||1|
Article is cited by:
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