JPS61141995A - Treatment of waste water containing water-soluble dye - Google Patents

Abstract

PURPOSE:To sufficiently perform the removal of a water-soluble dye, by adding a magnesium compound to waste water containing the water-soluble dye and subsequently making said waste water alkaline. CONSTITUTION:300-3000 ppm of a magnesium compound is added to waste water containing a water-soluble dye. subsequently, an alkali compound such as caustic soda, caustic potash or soda ash is added to waste water to adjust the pH thereof to 10-14 to sediment and separate the dye which is, in turn, separated and removed by filtering or centrifual separation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for treating wastewater containing water-soluble dyes.

(Prior Art) Conventionally, activated carbon adsorption treatment methods and ozone oxidation treatment methods are known as methods for decolorizing wastewater containing water-soluble dyes.

(Problems to be Solved by the Invention) However, these conventional methods require complicated equipment and complicated operations, and furthermore, it is difficult to remove dye coloration sufficiently.

(Objective of the Invention) An object of the present invention is to provide a method for treating wastewater containing a water-soluble dye to remove the coloring of the dye by a simple operation.

(Means for Solving the Problems) The present invention is a method of decolorizing wastewater containing water-soluble dyes by adding a magnesium compound to the wastewater containing water-soluble dyes and then making the wastewater alkaline. The gist is the processing method.

Water-soluble dyes that are the object of the present invention include reactive dyes, direct dyes, acid dyes, and the like. These may be those commonly used. For example, as reactive dyes, C,L Reactive Yellow 57, C,I@Reacti
veBlue (Reactive Blue 15, C
s1. ReactiveBlue
Blue) 112) C, 1, Reactive Black
(Reactive Black) 5 etc., direct dyes are C, 1, Direct Red (Direct v, t
C) 23, C, L Direct Brown 210, etc., and acid dyes such as C, I. Ac1d Red 158,
C,1,Ac1d Brown
333, etc., and for more details, the dyes etc. listed in the new edition dye handbook [edited by the Organic Synthetic Chemistry Association, Maruzen Stock % Formula %, pages 5 to 390 (direct dyes) and pages 391 to 526 (acid dyes). It will be done.

The magnesium compound of the present invention has the general formula g-X [wherein, X is C42]SO4, (OH)2)PO4, H
PO4H2PO4, HCO3, No5, (CH2COO
)2.0204 etc. ] Examples include compounds represented by:

Examples of alkaline agents that make wastewater containing magnesium compounds alkaline include caustic soda, caustic potash, soda ash, and slaked lime.

The amount of magnesium compound added is generally 300
~3000 ppm, and the degree of alkalinity is in the range of pH 10 to 14, but usually pH 10
, 5 to 12.0 is appropriate.

Although it is preferable to add the magnesium compound as an aqueous solution, there is no problem even if the magnesium compound is not completely dissolved, for example, some undissolved matter may be present.

After the treatment with the magnesium compound of the present invention, or simultaneously with the treatment with the magnesium compound, treatment may be performed with an inorganic or organic polymer flocculant conventionally generally used in wastewater treatment.

Examples of inorganic flocculants include aluminum sulfate, polyaluminum chloride, ferrous sulfate, and the like.

As the organic polymer flocculant, polyacrylamide (nonionic) [-CH2.CH-CONH2] is used. , polyacrylamide (anion) C-CH2・CH-Co・N
H2-).・[-CH2・CH-CO・0Na-]□,
Sodium polyacrylate (anion) [-CH2・CM
-Co-ONa-) n, etc.

By applying the method for treating wastewater containing water-soluble dyes of the present invention, the water-soluble dyes become flocs and are separated by sedimentation from the wastewater.

The flocs may then be separated and removed from the wastewater by an appropriate separation operation, such as filtration, centrifugal sedimentation, etc.

The wastewater treated and decolorized in this manner can be reused or discharged as is, or after further treatment such as voice control or microbial treatment.

(Operation and Effect) The mechanism by which the dye can be removed from coagulation by adding a magnesium compound to the wastewater containing the water-soluble dye of the present invention to make it alkaline is currently unknown.
It is thought that the insoluble salt produced when the magnesium compound reacts with an alkaline agent and becomes insolubilized has the property of conjugating and removing the dye.

By adding the magnesium compound of the present invention to wastewater containing a water-soluble dye and making it alkaline, most of the water-soluble dye can be sedimented and removed. COD can also be reduced.

(Examples, etc.) Next, the present invention will be described with reference to Examples, but the present invention is not limited to the Examples.

The coloring of the supernatant liquid after the treatments described in these examples was evaluated according to the following criteria.

Grade 5: No coloring at all Grade 4: Slightly colored Grade 3: Slightly colored 2nd grade, some coloring has been removed Class 1: The same color as the wastewater undiluted solution Example 1 This example is an example of the treatment of wastewater containing reactive dyes.

C,1,Roactiva Yellow 23 at 0.71/l, C,1,-Re
active Red (reactive red) 21 at 0.71/l, C, 1, Reactive Blue
e (reactive blue) 77 at 0.711/l,
A dye solution in which soda ash 2011/13 and Glauber's salt 5011/l were mixed and dissolved was heated at 60° C. for 60 minutes, further diluted 20 times with water, and adjusted to pH 9 with sulfuric acid, which was used as a wastewater stock solution.

Magnesium chloride hexahydrate was added to this wastewater stock solution to give a concentration of 2000 ppm as magnesium chloride, and then a 10% aqueous solution of caustic soda was added to adjust the temperature to 11.0. After about 20 minutes, a slightly colored supernatant was found. liquid (4
It was separated into floc) and floc.

Reference Example 1 After thoroughly stirring the supernatant liquid and precipitate obtained in Example 1, the anionic polymer flocculant trace acrylamide (
Sankyo Kasei Co., Ltd. Product name Sun 7J? Lee-305) 3
ppm and flocculation treatment, the degree of coloration of the supernatant liquid was the same as that of the supernatant liquid of Example 1, but the flocculation speed was as fast as about 1 minute. Good over-separation was achieved.

Comparative Example 1 A sulfuric acid band aqueous solution was added as aluminum sulfate to the wastewater stock solution of Example 1 to a total amount of 5000 plum, and then a 10% caustic soda aqueous solution was added to adjust the pH to 6.B.
To this liquid, add 3 ml of the anionic polymer flocculant described in Reference Example 1.
When a flocculation treatment was carried out by adding ppm, the coloring of the supernatant liquid was the same as that of the waste water stock solution (first grade).

Example 2 This example is also an example of treatment of wastewater containing reactive dye.

CAL Reactive Yellow '84 0.71/l, C,1,
Reac's veB1ue (reactive sol-) 5 to 0.7 El/IJ, C,1, Reac's veRe
d (reactive red) 120 0.71/13
.

A dye solution in which soda ash 2011/13 and 50 g/l of Glauber's salt were mixed and dissolved was heated at 80° C. for 60 minutes, further diluted 20 times with water, and adjusted to pH 9 with sulfuric acid to obtain a wastewater stock solution.

Thereafter, the same treatment as in Example 1 was carried out, and the coloring of the supernatant liquid was grade 4.

Comparative Example 2 The wastewater stock solution used in Example 2 was treated with animal acid band in the same manner as in Comparative Example 1. The coloring of the supernatant liquid was first grade.

Example 3 This example is of the treatment of wastewater containing direct dyes.

C, 1, Direct Yellow
Ye0-)86 0.71/13, C,I. Dir
ect Red (Direct Red) 243 to 0.
71/lSC, I* Direct Blue 192 at 0.7 g/l, and Glauber's Salt 2
A dye solution in which 0V4 was mixed and dissolved was heated at 95° C. for 60 minutes, and this was further diluted 20 times with water to obtain a wastewater stock solution.

Thereafter, the same treatment as in Example 1 was carried out, and the coloring of the supernatant liquid was grade 4.

Comparative Example 3 When the waste water stock solution used in Example 3 was treated with sulfate band in the same manner as in Comparative Example 1, the coloring of the supernatant liquid was second grade.

Example 4 This example is an example of treatment of acid dye-containing wastewater.

C, 1, Ac1d Red (Acid Red) 145
0.51/11, C, 1, Ac1d Black
A dye solution in which Acid Black 107 was mixed and dissolved at 1.5 V was heated at 95° C. for 60 minutes, and this was further diluted 20 times with water to obtain a wastewater stock solution.

Thereafter, the same treatment as in Example 1 was carried out, and the coloring of the supernatant liquid was grade 4.

Comparative Example 4 When the waste water stock solution of Example 4 was treated with sulfuric acid band in the same manner as in Comparative Example 1, the coloring of the supernatant liquid was first grade.

Example 5 Diamirror Yellow 5-RN at 2 g/l 1 A dye solution in which soda ash 2011/13 and Glauber's Salt 501//11 were mixed and dissolved was heated at 60°C for 60 minutes, and then diluted 20 times with water. The wastewater stock solution was prepared by diluting the solution and adjusting the pH with sulfuric acid.

Magnesium chloride, magnesium sulfate,
Magnesium nitrate, magnesium acetate, bugnesium phosphate, magnesium carbonate, magnesium hydroxide, or magnesium oxalate were added to each compound so that the amount was 2000 ppm, and the process was otherwise carried out in the same manner as in Example 1. The coloring of each supernatant was as follows.

Claims (3)

[Claims] (1) A method for treating wastewater containing water-soluble dyes, which comprises adding a magnesium compound to wastewater containing water-soluble dyes, and then decolorizing the wastewater by making it alkaline. (2) A method for treating water-soluble dye-containing wastewater according to claim 1, wherein the alkalinity is pH 10 or higher. (3) In the method for treating water-soluble dye-containing wastewater according to claim 1, the alkaline pH is 10.5 to 12.0.
A method that is within the range of.