Study on Degradation Efficiency of Common Hand Dyes by Fenton/Persulfate process

• Main Authors: LI,YUN, 李芸
• Other Authors: Horng,Jao-Jia
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/5b3dh8

碩士 === 國立雲林科技大學 === 環境與安全衛生工程系 === 105 === Dye-finishing wastewater has come to attentions due to dumping pollution of popular, traditional hand-dyed clothes. This study tested the Fenton and persulfate methods on degrading the common dyes such as Indigo, Alizarin, Laccaic acid and Hematoxylin, in order to apply them on decoloring and mineralization with degradation factors, optimal conditions. Those acid and base dyes would be degraded at different pHs with different test conditions. The acidic Alizarin and Laccaic acid would use the Fenton method for degradation, the alkaline Indigo would apply the persulfate degradation, and the amphoteric Hematoxylin would use both methods for degradation. During decoloring Alizarin and Laccaic acid at pH 3 by adding Fe2 +and H2O2, the optimal decoloring rates were higher than 90% while Laccaic acid yielded highest mineralization rate (70 %). The decoloring Indigo experiments at pH 10 on the room or 70℃showed higher decoloring at 70℃ with the degradation effects related to their solubility with the highest degradation rate to 96%. As Hematoxylin decolored by the Fenton and persulfate methods effectively reaching above 90% with mineralization rate higher by persulfate method (87%) over Fenton (44%).. The kinetic stud of the decoloring reactions showed that the Fenton method reacted on Hematoxylin with zero order reaction of constant k 0.562 mole L-1s-1. The Alizarin and the Hematoxylin by the persulfate method were both first-order reactions with constant k values 0.0038 s-1 and 0.00111 s-1, respectively. The Laccaic acid and Idigo decoloring by Fenton method were second-order reactions with constants k values of 0.0000084 Lmol-1s-1 and 0.0000187 Lmol-1s-1. As the TOC representing mineralization effects, all the dyes’ Fenton reactions were first-order kinetics with constant k values of Indigo, Alizarin, and Laccaic acid with Fenton 0.0135 s-1, 0.0097 s-1, 3848 s-1, and Hematoxyl with Fenton 0.0057 s-1 and with persulfate 0.006 s-1. Our results showed that the hand-dyes wastewater treatment should first determine their pH values. Then, the appropriate treatment method should be used for degradation with decoloring above 90% and mineralization above 40%. Alkaline persulfate mineralization rate would continue to increase after 3 hours. Keywords: Fenton, Persulfate, hand-dyes, Indigo, Alizarin, Laccaic acid and Hematoxylin