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Green Decoloration Of Dye In Waste Water By Zero Valent Iron, EDTA And Air

Posted on:2010-06-24Degree:MasterType:Thesis
Country:ChinaCandidate:Y J WangFull Text:PDF
GTID:2121360278996823Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
This paper briefly summarizes waste dye water degradation technologies that follow green chemistry principles. For the ideal characteristics of green chemistry pollutant destruction, i.e. reaction conditions under RTP and the use of inexpensive and nontoxic reagents, the iron based ZEA (zero-valent iron, EDTA, air) reaction shows high oxidative activity and has been widely used in organic pollutant destructions. This thesis describes two different kinds of dye are successfully degraded by the new ZEA reaction and also some mechanistic discussions and studies are done aimed at understanding the activity of the process in detail.Chapter 2 descibes the whole process utilizing green wet oxidation technology- (zero-valent iron, EDTA, air) to degrade wastewater containing dye Fuchsine. The reaction conditions are optimized and the method can get satisfied results for remove the color of the dye. At the same time the hydroxyl radical concentration is measured in the process. We also discuss the possible mechanism of the reaction.Chapter 3 details a new oxidation process designed as a green decoloration of wastewater containing dye, namely brilliant green (BG). The investigation revealed that the method can remove the color of the dye completely. The results show the dye rapidly undergoes decoloration just using air as the oxidant under room temperature and atmosphere pressure. Various factors such as the pH, the initial concentration of dye and the temperature are examined. We found increasing the temperature enhances the dye decolorization. Also, the buffer under low pH is critical to improve the reaction rate. The optimum pH in this study is about pH 3.6. The mechanism and reaction kinetic for the decolorization of dye in the process is also discussed.Chapter 4 The ZEA system is unique in that it can produce a kinetically facile oxidative environment by the production of H2O2, HO·and other reactive oxygen species in situ by the activation of molecular oxygen. In this part we describe high performance liquid chromatographic assay of hydroxyl free radical using salicylic acid hydroxylation during dye waste water treatment involving ZEA. It proves indirectly the hydroxyl free radical exist in the ZEA system from the assay products2, 5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid and 1,2-benzenediol.
Keywords/Search Tags:Zero valent iron, EDTA, Air, Dye degradation, Green oxidation
PDF Full Text Request
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