Title: Decolourization of Dye and Textile Effluent using Advanced oxidation processes
Abstract: Industrialization is vital to nation’s economy because it serve as a vehicle for development. The world’s ever increasing population and its progressive adoption of an industrial based lifestyle has inevitably led to an increased anthropogenic impact on the biosphere. Increasing urbanization and industrialization have thus resulted in a dramatic increase in the volume of wastewater. Global water pollution scenario suggests that nearly 1.5 billion people lack safe drinking water and at least 5 million deaths are attributed to waterborne diseases such as cholera, hepatitis every year. The major industries contributing to water pollution are – textile mills, electroplating industry, metal processing industry, pulp and paper mill and tannery industry. The effluent generated from such industries generally contains alkanes, haloalkanes, polymers, surfactants, aromatic dyes etc. These compounds are toxic and persistent in nature Therefore it becomes imperative to completely degrade these organic compounds. Major pollution in textile effluent is due to high suspended solids, chemical oxygen demand, heat, color, acidity and other non biodegradable substances. In order to tackle this menace of pollution problem, it is desirable to degrade the dye into non toxic form before its discharge into the main stream. The traditional treatment techniques applied in textile wastewaters, such as coagulation/flocculation, membrane separation (ultrafiltratation, reverse osmosis) or elimination by activated carbon adsorption, only do a phase transfer of the pollutant, and biological treatment is also not a complete solution to the problem. So Advanced Oxidation Processes (AOP s), like Fenton and Photo-Fenton processes, could be a good option to treat and eliminate textile dyes. Advanced Oxidation Processes are the one that offers a highly reactive, non-specific oxidant namely hydroxyl radicals (HO), capable of destroying wide range of organic pollutants in water and wastewater. Fenton’s reagent oxidation is a homogeneous catalytic oxidation process using a mixture of hydrogen peroxide and ferrous ions. The main advantage of the Fenton’s reagent is its simplicity in usage. In an acidic environment if hydrogen peroxide is added to an aqueous system containing an organic substrate and ferrous ions, a complex redox reaction will occur. The work done has been presented in five chapters. After introducing the problem and its content in the first chapter, the study begins with the background history of AOP’s in second chapter. Then literature review on Fenton and Photo Fenton decolourization of various dyes and textile effluents has been given in the third chapter. The fourth chapter discusses experimental materials and methods that have been employed. Results and their discussion for decolourization of model dye compound and real effluent has been presented in fifth chapter. In the present study, industrial effluents were collected from textile mill and its characterization was done by measuring pH, EC, total solids, TSS, TDS, COD, and Color etc. Decolourization studies of Malachite Green dye was carried out with Photo Fenton process in specially designed reaction vessel in the photo reactor equipped with UV tubes. Experiments were performed in both UV and solar light at optimized condition. The decolourization of dye and textile effluent has been investigated in terms of change in color by measuring absorbance and reduction in COD. Various process parameters like pH, concentration of oxidant, Fenton ratio, and initial pollutant concentration were varied and their effects have been analyzed. The objective was to determine the best treatment for reducing color and COD of these colored solutions. In the case of MG dye (25 ppm), Fenton ratio 3:1 and oxidant dose was optimized at 300:100 mg/l at 2.0 pH. At optimized conditions 82% reduction in color is obtained. In case of textile wastewater pH optimized was 2.0, Fenton ratio of 3: colour, 61% reduction in TDS and 76% removal of COD in 4hrs. of exposure. In some technological cycles of dye industry, it is necessary only to remove the color completely, and sometimes it is necessary to purify water slightly to enable its re-use as cooling or technological water so these Fenton and Photo-Fenton processes can be used efficiently and cost effectively for color elimination and biodegradability improvement of dyes effluents in order to close water circulation in factories, which results not only in economic but above all ecological advantages.
Publication Year: 2008
Publication Date: 2008-09-24
Language: en
Type: dissertation
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Cited By Count: 4
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