engleski

Photocatalytic degradation of Reactive dye in aqueous solution

Due to their negative influence on natural watercourse the presence of coloured wastewaters in the environment is undesirable from both aesthetic and environmental point of view. Wastewaters from dye production and application processes usually contain dyes as well as various by-products and auxiliary chemicals which are besides being poorly biodegradable often found to be toxic and carcinogenic. Therefore, there is a clear need to treat such wastewaters before they are discharged into the recipient. Technologies based on conventional physical and biological methods do not often prove to be sufficiently effective. Advanced Oxidation Processes (AOPs) in which highly reactive hydroxyl radicals are generated under the influence of chemical, electrical or radioactive energy distinguish themselves as the ones with the ability of quick and efficient degradation of organic pollutants in water and carbon dioxide with the minimum production of secondary waste. In this work the research into the application of UV, UV/TiO2, UV/H2O2, UV/H2O2/TiO2 i UV/H2O2/TiO2/Fe2+ processes of degrading reactive azo dye C.I. Reactive Red 45 (RR45) as a model pollutant in wastewater has been done. The influence of the change in pH, mass of photocatalyst, concentration of hydrogen peroxide and the ratio of Fenton's reagents on the efficiency of UV/H2O2/TiO2 and UV/H2O2/TiO2/Fe2+ processes has been monitored. Values of the process parameters yielding with the highest decolorization and mineralization degree of the model wastewater have been established. It has been demonstrated that the efficiency of degradability increases in the sequence UV < UV/TiO2 < UV/H2O2 < UV/H2O2/TiO2 < UV/H2O2/TiO2/Fe2+. By the application of UV/H2O2/TiO2/Fe2+ process the model wastewater becomes completely decolourized and the organic matter content is decreased by 89, 0 %. Considering obtained values of the water quality parameters ; color, TOC, AOX, KPK and BPK5, the treated wastewater meets the criteria required for discharging water into natural recipients of the 4th and 5th categories as well as into the public sewage system.

AOPs; photo degradation; reactive dye; TOC; decolorization

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