JPH06233987A - Treatment of waste dye liquid - Google Patents

Abstract

PURPOSE:To make it possible to separate and remove reactive dye from an aqueous solution containing the reactive dye early and efficiently by adding alkaline earth metal salts to an aqueous solution with pH higher than a specified value which contains the reactive dye and separating a deposited substance. CONSTITUTION:Alkaline earth metal salts (e.g. calcium chloride) are added to an aqueous solution with pH higher than 9 which contains reactive dye to separate a deposited substance. The addition amount of the alkaline earth metal salts is preferably 10 to 60g/liter in terms of anhydride. This treatment method solves pending issues peculiar to a conventional technology such as deterioration of a removal rate of pollutant due to the insufficient quantity of an organic coagulation sedimentation agent, which is attributed to a variation of pollutant concentration in waste water, or an increase in BOD, COD due to the excessive removal rate, and some problems of the removal rate of pollutant due to the use of a strongly acidic inorganic coagulation sedimentation agent as well as the difficulty of controlling the pH value in such case. Further, it is possible to separate and remove reactive dye from an aqueous solution containing the reactive dye easily and efficiently, without using a substance which falls under the provision of the enforcement ordinance of the water quality contamination inhibitive law for human health and life environments as a treatment chemical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a dye waste solution for removing a reactive dye from an aqueous solution containing the reactive dye. More specifically, a cloth containing cellulosic fibers,
The present invention relates to a method for treating a waste liquid containing a reactive dye that has been used or has been used in a dyeing method such as a cold pad batch method, a pad steam method, or another dyeing method for various fibers.

[0002]

2. Description of the Related Art As a method for treating wastewater, there is a method using a coagulating sedimentation agent. This method includes the use of an inorganic flocculating precipitant such as a sulfuric acid band, polyaluminum chloride, ferric sulfate, and ferrous chloride alone or in combination, cationic, anionic, specific ion, amphoteric organic polymer flocculation. The precipitating agent is used alone or in combination, or the inorganic flocculating precipitating agent and the organic polymer flocculating precipitating agent are added together, and the flocculate is sedimented and floated under pressure.
This is a method of separating and removing pollutants in wastewater by a method such as filtration. However, the sulfuric acid band and polyaluminum chloride are strongly acidic substances, and it is necessary to use a large amount when the concentration of pollutants in wastewater is high. Substance concentration,
It is not easy to manage and control the pH of treated water. The use of iron salt is a problem that the yellowish brown chromaticity due to the iron salt remains,
(Issue, Industrial Water Survey, Water Handbook (2) No. 3
Pp. 864 (Sho 56)), there is a difficulty in removing dissolved iron regulated by the Water Pollution Control Law. The use of organic polymer flocculant-precipitating agent is also less effective when the amount is less than the proper amount, and biochemical oxygen demand (BOD) or chemical oxygen demand (COD) when the treated amount is more than the proper amount. The problem is that it leads to an increase in the number of particles and an increase in aggregated precipitates.

In particular, a cloth containing cellulosic fibers is treated by a cold pad batch method, a pad steam method, etc.
The above-mentioned difficulties become remarkable in the treatment of high-concentration waste liquids having different dye concentrations for each color, such as waste liquids after dyeing using a reactive dye and unused waste liquids that are excessively dissolved.

[0004]

The object of the present invention is to remove the dye from an aqueous solution containing a reactive dye by the above-mentioned difficulty, namely, treatment by using a strongly acidic substance such as a sulfuric acid band or polyaluminum chloride. Difficulties in controlling and controlling pH of water and controlling and controlling concentrations of pollutants, problems of dissolved iron in treated water due to the use of iron salts, and difficulty in managing and controlling the proper amount of use due to the use of organic polymer flocculants. And BOD / COD
It is to provide a processing method that solves difficulties such as the risk of increase.

[0005]

The present invention contains a reactive dye which is characterized in that an alkaline earth metal salt is added to an aqueous solution containing a reactive dye and having a pH of 9 or more to separate a precipitated substance. This is a method for treating a dye waste liquid, which removes a reactive dye from an aqueous solution. In the present invention, when the pH of the aqueous solution containing the reactive dye is less than 9, the pH is adjusted by adding an alkali.
It is necessary to be 9 or more.

Examples of the caustic alkali used in the present invention include hydroxides of alkali metals such as caustic soda and caustic potash. These caustic alkalis may be used alone or in combination of two or more. When a cloth containing cellulosic fibers is dyed by a two-bath cold pad batch method, a two-bath pad steam method, etc., the first bath contains no caustic.
It is efficient to adjust the waste liquid containing the reactive dye in the first bath to pH 9 or more with the waste liquid of caustic alkali contaminated with the reactive dye dropped in the second bath. PH is 9 or more, preferably 10 or more and 13 or less. When the pH is 13 or more, the amount of caustic used is simply increased. The waste liquid containing the reactive dye obtained by the one-bath cold pad batch method and the one-bath pad steam method contains caustic alkali, and since the pH is 9 or more, it is not necessary to add caustic alkali. After the reactive dye is fixed to the cellulosic fiber, the unfixed reactive dye is removed from the cellulosic fiber and washed. If the cleaning liquid is pH 9 or less, caustic alkali is added to adjust the pH to 9 or more.

As the alkaline earth metal salt used in the present invention, there is a water-soluble neutral salt of an alkaline earth metal such as calcium chloride or magnesium sulfate. These alkaline earth metal salts may be used alone or in combination of two or more. When an alkaline earth metal salt is added to a waste liquid containing a reactive dye and having a pH of 9 or more, the alkaline earth metal salt is in an aqueous solution state,
It may be solid. Preferably, in order to prevent the treated water amount from increasing, a method of adding and stirring to a solid or waste liquid, or in the case of a granular or agglomerated solid, a method of grinding in the waste liquid is preferable. In the present invention, the addition amount of the alkaline earth metal salt is not limited, but it is preferably 5 gr / l or more as an anhydride, more preferably 10 gr / l or more and 60 gr / l or less. 5 gr
When the amount is less than 1 / l, the effect is small, and when the amount used is more than 60 gr / l, the amount of increase in the precipitate is often large with respect to the dye removing effect.

In order to finally control the treated waste liquid to have an appropriate pH, an acid may be added to control the pH as appropriate prior to the addition of the alkaline earth metal salt. In the present invention, the temperature and time of each treatment step are not limited, but the temperature of the pad bath dyed by the cold pad batch method or the pad steam method is generally 20 to 25 ° C., and the present invention is particularly cooled. -Preferably 2 because there is no need to raise the temperature
0 to 25 ° C. The processing time of each processing step is 0.5 hours to 2 hours required for mixing waste liquids, adjusting pH, adding each drug, mixing, stirring, dissolving, homogenizing, etc., but adding, mixing, stirring each drug. Alternatively, it may be left for one day after dissolution.

The waste liquid treated by the treatment method of the present invention is
Known methods of the substance precipitated from the waste liquid, that is, separation and removal from the supernatant liquid by static sedimentation, filtration separation with various filter media, press filtration with various filter cloths, solid-liquid separation with a centrifugal dehydrator, etc. are effective. is there.

[0010]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The treatment temperature is not constant because it increases with the addition of each chemical, but it is within the range of 20 to 25 ° C. Parts in the examples are parts by weight. The removal rate of the dye was determined by the change in the absorbance at the wavelength where the absorbance of the aqueous dye solution in the visible light wavelength region was the maximum.

[0011]

Example 1 Remazol Brilliant Blue B, which is a reactive dye manufactured by Mitsubishi Kasei Hoechst Co., Ltd., in 50 parts of water
(Abbreviated as CI No. B27. The same applies hereinafter.) An aqueous solution in which 2 parts were dissolved and an aqueous solution in which 1 part of caustic soda was dissolved in 50 parts of water were mixed. PH of the mixed aqueous solution is 1
It is 2.6. After leaving the aqueous solution for 1 hour, 2 parts of lumpy anhydrous calcium chloride was added, ground and stirred, and after 1 hour,
It was filtered with qualitative filter paper No. 2 manufactured by Toyo Roshi Kaisha, Ltd. The removal rate was 96%. In Comparative Example 1, the removal rate was 39% when caustic soda was not added and calcium chloride was added, and in Comparative Example 2, the removal rate was 0% when caustic soda was added but no calcium chloride was added. there were.

[0012]

Example 2 50 parts of water contained C.I. I. No. An aqueous solution prepared by dissolving 2 parts of B27 and an aqueous solution prepared by dissolving 2 parts of caustic soda in 50 parts of water were mixed and allowed to stand for 1 hour.
Add 6 parts of hydrate, stir and dissolve, and after 30 minutes, use a filter made of polyester-based synthetic fiber nonwoven fabric with an average pore size of 67 μm (Product name / ALTUS, Type / EYE, product number / E1050, manufactured by Asahi Kasei Corporation). Filtered. The removal rate was 92%. As Comparative Example 3, the one without caustic soda added with magnesium sulfate had a removal rate of 0%, and as Comparative Example 4 one with caustic soda added but without magnesium sulfate had a removal rate of 0%. there were.

[0013]

[Example 3] Sumifix Red B (CIN) which is a reactive dye manufactured by Sumitomo Chemical Co., Ltd. in 100 parts of water
o. R22) 1 part, caustic soda 2 parts, anhydrous sodium carbonate 2 parts, and urea 2 parts are dissolved, and 98% sulfuric acid is added to an aqueous solution left for 1 hour and stirred to adjust to PH 11.0, and anhydrous Add 5 parts of calcium chloride, grind, stir, and mix 3
After 0 minutes, it was filtered as in Example 2. The removal rate was 98%. In Comparative Example 5, an aqueous solution containing no caustic soda, sodium carbonate, and urea, to which calcium chloride was added, the precipitate passed through the filter and could not be removed and separated. In Comparative Example 6, after caustic soda was added, In the case where calcium chloride was not added, the removal rate was 51%, which was insufficient. That is, the dye concentration in the aqueous solution after the treatment of Comparative Example 6 was 24.5 times the dye concentration in the aqueous solution after the treatment of Example 3.
It was double.

[0014]

[Example 4] Remazol / Yellow / GR in 100 parts of water
(CI No. Y15) 0.5 part, caustic soda 2 parts, anhydrous sodium carbonate 2 parts and urea 2 parts were dissolved, and 5 parts of anhydrous calcium chloride was added to an aqueous solution left for 1 hour. The mixture was ground, stirred, and after 30 minutes, filtered in the same manner as in Example 1. The removal rate was 95%. As Comparative Example 7, the removal rate of calcium chloride added to an aqueous solution containing no caustic soda, sodium carbonate, and urea was 5%. As Comparative Example 8, an aqueous solution containing caustic soda, sodium carbonate, and urea was added.
When calcium chloride was added, the removal rate was 0%.

Table 1 shows the conditions and results of the above Examples and Comparative Examples.

[0016]

[Table 1]

[0017]

EFFECTS OF THE INVENTION The treatment method of the present invention reduces the removal rate of organic polymer coagulant / precipitant from insufficient amount due to fluctuations in the pollutant concentration of waste water of the prior art, or reduces BOD / COD from excess.
And the difficulty of pH control at the time of removal of pollutants by the use of strong acidic inorganic coagulant settling agent, and the health of human beings stipulated by the Ordinance for Enforcement of the Water Pollution Control Act. The reactive dye can be easily and efficiently separated and removed from the aqueous solution containing the reactive dye without using a substance related to the living environment as a treating agent.

Claims (1)

[Claims] 1. A reactive dye is removed from an aqueous solution containing a reactive dye, characterized in that an alkaline earth metal salt is added to an aqueous solution containing a reactive dye and having a pH of 9 or more to separate a precipitated substance. Dye waste liquid treatment method.