Comparison of Dye Colour Removing with Electrochemical and Chemical Processes

• Main Authors: Feng-Hung Tseng, 曾馮弘
• Other Authors: Luke Chen
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/35682877110483643410

碩士 === 淡江大學 === 水資源及環境工程學系碩士班 === 94 === To sustain color in textile, several chemicals are usually added into dye to enhance the attachment of the dye on the textile. Hence the added chemicals induce pollution problem of the waste water, especially its color. The amount of dye related chemicals is about 50% of the total waste water. The color of the waste water is one of the water pollution indices which evoke people’s direct impression of water quality. Small amount of dissolved dye can cause decrease of water transparency and solubility of gases. Since most dyes are made of compounds with high molecular weight, they are difficult to be treated with biological processes. Several means are considered to remove color of waste water caused by dye; however rare processes are able to remove color and COD at the same time. Other than the technical drawback, the treatment cost usually prohibits their long term application. Past study has proved that electrochemical method (low voltage DC.) is capable to be used in removing color in waste water effectively in laboratory scale. Because the direct electrochemical method requires considerable space that limit its application in many site retrofit, an indirect electrochemical method is considered in this study. A chemical process is introduced first to produce coagulant and then an electrical method is applied in sequence to remove dye caused color in waste water. The findings from this study may be concluded as below: 1.Both direct method and indirect method Fe-coagulation processes are effective for color removal from textile effluents. 2.Sodium chloride is essential in this process because the existence of NaCl reduces power consumption. 3.The by-product of the process, NaClO, is a strong oxidizing agent that can be used to further decompose the dye structure. 4.The Fe-coagulation process is effective for color removal from textile effluents. 5.Chemical method also is a good choice for color removal from textile effluents. 6.The sludge of electrochemical methods are more stable than that of chemical method.