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Method for recycling bipseudoindoxyl dye from indigo dyeing waste water

A technology for indigo dye and dyeing wastewater, applied in the direction of bis-indole indigo indigo dye, organic dyes, chemical instruments and methods, etc., can solve the problem of poor recovery of indigo dye and removal of fibers and solid impurities without mentioning pretreatment , There are no clear oxidation conditions and other issues, to achieve the effect of small investment, COD reduction, and simple equipment

Active Publication Date: 2009-03-04
溧阳常大技术转移中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, these methods do not mention pretreatment to remove fiber and solid impurities, there is no clear oxidation condition, and the recovery effect of indigo dye is not good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Take 10L of indigo dyeing wastewater from a printing and dyeing factory, its chroma is 1024 times, turbidity is 1430 NTU, and COD is 1800mg / L. After filtering through non-woven fabrics PP25 and PP5 successively, adjust the pH value with 1:1 sulfuric acid solution, oxidize with air for 2 hours, and control the pH value to 4. Then it is filtered through 0.2μm PE membrane, and the operating pressure is 0.08Mpa. The recovered indigo dye can be used for fabric dyeing. After membrane treatment, the effluent basically does not contain indigo dye, its chromaticity is 8 times, and the removal rate is 99.2%; the turbidity is 5 NTU, which is reduced by 99.7%; the COD is 960mg / L, and the removal rate is 46.7%.

Embodiment 2

[0015] Take 8L of indigo wastewater from a printing and dyeing factory, the chroma is 516 times, the turbidity is 932NTU, and the COD is 1960mg / L. After filtering through non-woven fabrics PP25 and PP5, adjust the pH value with sulfuric acid solution, oxidize with air for 30 minutes, and control the pH value to 2. Then it is filtered through 0.1μm PE membrane and the operating pressure is 0.05Mpa. The retained indigo dye can be used for fabric dyeing. The effluent after membrane treatment does not contain indigo dye, its chromaticity is 8 times, the removal rate is 98.5%, and the turbidity is 3.6 NTU, which is reduced by 99.6%. COD 690mg / L, removal rate 64.8%.

Embodiment 3

[0017] Take 8L of indigo dyeing wastewater from a printing and dyeing factory, the chroma is 2024 times, the turbidity is 3152 NTU, and the COD is 2530mg / L. After filtering through non-woven fabrics PP25 and PP5, adjust the pH value with sulfuric acid solution, oxidize with air for 3 hours, and control the pH value to 6. After filtration through 0.5μm PE microfiltration membrane, the operating pressure is 0.1Mpa. The recovered indigo dye can be used for fabric dyeing. After membrane treatment, the chromaticity of the effluent is 32 times, the removal rate is 98.4%, and the turbidity is 18.9 NTU, which is reduced by 99.4%. COD1720mg / L, removal rate 32%.

[0018] Example 4

[0019] Take 8L of indigo dyeing wastewater from a printing and dyeing factory, the chroma is 2024 times, the turbidity is 3560 NTU, and the COD is 3920mg / L. After filtering through non-woven fabrics PP25 and PP5, adjust the pH value with sulfuric acid solution, oxidize with air for 4 hours, and control t...

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Abstract

The invention discloses a method for recycling an indigo dye from the indigo waste coloring water. In the method, a proper filtration fabric is selected first for filtering the fibers and impurities in the waste water; then an acid liquid is added into the waste water the fibers and impurities of which are removed to adjust the pH value between 2 and 7; air is blown for oxidation to oxidize sodium salt of a water-soluble indigo leuco body into an insoluble solid indigo dye; finally the indigo dye and a condensed liquid which is rich in the dye are obtained through a microfiltration membrane device. The method has the advantages of less investment and simple device; the recycled indigo dye and the recycled condensed liquid can be recycled for coloring a fabric; besides, after the indigo waste coloring water is treated by the membrane, the chroma, the turbidity and the COD, and the like, are greatly reduced. The removing rate of effluent color dilution after the membrane treatment is larger than 98 percent; the turbidity is reduced by more than 97 percent and the COD removing rate is larger than 30 percent.

Description

technical field [0001] The invention relates to a wastewater treatment method, in particular to a method for recovering indigo dye from indigo dyeing wastewater. Background technique [0002] Indigo is the most widely used synthetic dye for textiles in the world. Indigo dyeing uses the exhaust dyeing method to dye the yarn. The indigo dyeing rate is low, and nearly 20% of the indigo dye cannot be dyed. The factory first adopts the method of multiple dip dyeing / oxidation to obtain better color fastness and dyeing depth, and then washes with water to remove floating colors and stains on the surface of the yarn, which will generate a large amount of dyeing wastewater, which has a large chroma, High COD is one of the most difficult to treat printing and dyeing wastewater. At present, most of the treatment methods aim to meet the discharge standards. The molecular structure of indigo is stable, so the treatment is difficult. [0003] At present, the recovery methods of indigo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09B7/02C09B67/54C02F9/04C02F1/66C02F1/72
Inventor 邱滔徐圃清张晟石剑虹刘子辉
Owner 溧阳常大技术转移中心有限公司
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