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THE COAGULATION OF DISPERSE DYES Thomas Crowe, Graduate Student Charles R. O'Melia, Professor Linda Little, Associate Professor Department of Environmental Sciences and Engineering University of North Carolina Chapel Hill, North Carolina 27514 INTRODUCTION The purposes of this research were (a) to determine conditions under which color from disperse dyes can be removed by coagulation, and (b) to describe the mechanisms by which disperse dyes are destabilized by conventional coagulants. Experiments have been conducted with two disperse dyes. The coagulants used included synthetic cationic, nonionic and anionic polymers and also alum. For several dye-coagulant combinations, color removal was studied as a function of the concentrations of dye and of dispersing agent, and also pH. EXPERIMENTAL MATERIALS AND METHODS The dyes used are termed Disperse Yellow # 3 and Disperse Yellow # 42. The molecular structure of the dye molecules is as follows: Disperse Yellow #3 Disperse Yellow #42 O NOa These dye molecules are insoluble in water and are actually present in wastewaters as solid colloidal particles. The dye particles are maintained in a colloidal state by the addition of a negatively charged sulfonated lignin termed REAX-85A. The dyes were supplied by the American Dye Manufacturers Institute (ADMI) as dispersions containing 15% by weight of both the active dye ingredient and the dispersing agent. Additional REAX-85A was supplied by Westvaco. The destabilizing chemicals investigated were Nalco 603, Nalco 7132 and Cat-floc (Cal- gon) cationic polymers, Nalco 7744B anionic polymer, Nalco 8171 nonionic polymer and alum. Polymer characteristics presented here are based on manufacturers' data. Nalco 603 has a molecular weight of about 50,000 and is a liquid. Nalco 7132 has a molecular weight of about 150,000 and is a liquid. For both of these polymers, a concentrated stock solution (100 g/1) was prepared weekly. A more dilute solution (2 g/1) was then prepared daily for use in coagulation (jar) tests. Cat-floc has a molecular weight of about 500,000 and is a liquid. Stock solutions of 2 g/1 were used in the jar test experiments. Nalco 7744B is a liquid that is soluble in water to about 7.5 g/1 at room temperature. Stock solutions of 2 g/1 were used. Nalco 8171 is a liquid that is quite soluble in water; again, stock solutions of 2 g/1 were used. Alum stock solutions were prepared from reagent-grade alum, (Al^SO*^- 18H20). Stock solutions of 50, 2 and 1 g/1 were used, depending on the dosage being investigated. Dye concentrations were measured by dissolving the dye in a 1:1 mixture with 95% etha- nol and measuring absorbance vs a similar ethanol-water mixture in a Beckman DU spectrophotometer. These absorbance measurements were made at wavelengths of 356 nm and 415 nm for Disperse Yellow # 3 and Disperse Yellow #42, respectively. 655
Object Description
Purdue Identification Number | ETRIWC1977067 |
Title | Coagulation of disperse dyes |
Author |
Crowe, Thomas O'Melia, Charles R. Little, Linda W. |
Date of Original | 1977 |
Conference Title | Proceedings of the 32nd Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://e-archives.lib.purdue.edu/u?/engext,26931 |
Extent of Original | p. 655-662 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-07-01 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 655 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | THE COAGULATION OF DISPERSE DYES Thomas Crowe, Graduate Student Charles R. O'Melia, Professor Linda Little, Associate Professor Department of Environmental Sciences and Engineering University of North Carolina Chapel Hill, North Carolina 27514 INTRODUCTION The purposes of this research were (a) to determine conditions under which color from disperse dyes can be removed by coagulation, and (b) to describe the mechanisms by which disperse dyes are destabilized by conventional coagulants. Experiments have been conducted with two disperse dyes. The coagulants used included synthetic cationic, nonionic and anionic polymers and also alum. For several dye-coagulant combinations, color removal was studied as a function of the concentrations of dye and of dispersing agent, and also pH. EXPERIMENTAL MATERIALS AND METHODS The dyes used are termed Disperse Yellow # 3 and Disperse Yellow # 42. The molecular structure of the dye molecules is as follows: Disperse Yellow #3 Disperse Yellow #42 O NOa These dye molecules are insoluble in water and are actually present in wastewaters as solid colloidal particles. The dye particles are maintained in a colloidal state by the addition of a negatively charged sulfonated lignin termed REAX-85A. The dyes were supplied by the American Dye Manufacturers Institute (ADMI) as dispersions containing 15% by weight of both the active dye ingredient and the dispersing agent. Additional REAX-85A was supplied by Westvaco. The destabilizing chemicals investigated were Nalco 603, Nalco 7132 and Cat-floc (Cal- gon) cationic polymers, Nalco 7744B anionic polymer, Nalco 8171 nonionic polymer and alum. Polymer characteristics presented here are based on manufacturers' data. Nalco 603 has a molecular weight of about 50,000 and is a liquid. Nalco 7132 has a molecular weight of about 150,000 and is a liquid. For both of these polymers, a concentrated stock solution (100 g/1) was prepared weekly. A more dilute solution (2 g/1) was then prepared daily for use in coagulation (jar) tests. Cat-floc has a molecular weight of about 500,000 and is a liquid. Stock solutions of 2 g/1 were used in the jar test experiments. Nalco 7744B is a liquid that is soluble in water to about 7.5 g/1 at room temperature. Stock solutions of 2 g/1 were used. Nalco 8171 is a liquid that is quite soluble in water; again, stock solutions of 2 g/1 were used. Alum stock solutions were prepared from reagent-grade alum, (Al^SO*^- 18H20). Stock solutions of 50, 2 and 1 g/1 were used, depending on the dosage being investigated. Dye concentrations were measured by dissolving the dye in a 1:1 mixture with 95% etha- nol and measuring absorbance vs a similar ethanol-water mixture in a Beckman DU spectrophotometer. These absorbance measurements were made at wavelengths of 356 nm and 415 nm for Disperse Yellow # 3 and Disperse Yellow #42, respectively. 655 |
Resolution | 300 ppi |
Color Depth | 8 bit |
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