TW201439014A - Method for treating development wastewater from color filter production step - Google Patents

Abstract

A method for treating a development wastewater resulting from a color filter production step is provided with which prior to a biotreatment, biological oxidation treatment, or another treatment of the development wastewater resulting from a color filter production step, the solid matter and dissolved substances contained in the development wastewater resulting from a color filter production step can be efficiently coagulated. The method for treating a development wastewater resulting from a color filter production step comprises: a pH regulation step in which an acid is added to the development wastewater resulting from a color filter production step to regulate the pH to 5 or less; a cationic-coagulant addition step in which a cationic coagulant is subsequently added; an anionic-coagulant addition step in which an anionic coagulant is thereafter added; and a solid-liquid separation step in which the resultant wastewater is subjected to solid-liquid separation. An inorganic coagulant may be added either in the pH regulation step, or between the pH regulation step and the cationic-coagulant addition step, or between the cationic-coagulant addition step and the anionic-coagulant addition step.

Description

Method for processing development drainage of color filter manufacturing step

The present invention relates to a treatment method for developing drainage in a color filter manufacturing step, and more particularly to a treatment method for developing drainage in a color filter production step using a coagulant.

In the production of a color filter, a pattern forming method (color resist method) by development of a photoresist of a dispersed pigment is used. The color resist liquid used in the color filter production step contains a pigment, an alkali-soluble resin (alkali-soluble polymer), a photopolymerizable component (monomer), a photopolymerization initiator, a dispersant, and a solvent.

In the development step in the color filter manufacturing step, when the unexposed (unhardened) color photoresist liquid is washed away by the developer, color filter development drainage occurs. The developer system is generally highly alkaline and contains a large amount of nonionic surfactant.

The color filter development drainage contains heavy metals such as copper, nickel, zinc, and the like, and a high concentration of COD components, and has a coloration from the pigment.

In the past, as a treatment method containing pigment drainage, the first step of (i) removing the pigment and (ii) the biological treatment or the ozone treatment or the Fenton treatment to promote the oxidation treatment to dissolve the dissolved organic matter to CO ₂ are mainly employed. Combination processing of steps (Non-Patent Document 1, Patent Documents 1 to 3). In the latter step (ii), in addition to the oxidation treatment of the organic substance, there are cases in which (iii) adsorption treatment such as activated carbon treatment is used. There are also steps for combining all of (i) to (iii) depending on the purpose of the treatment. There is also a treatment method in which the pretreatment is not performed in the treatment of the drainage of the drainage of the color filter drainage, and the coagulation treatment is performed after the biological treatment (Patent Document 4).

As a method of removing the pigment, there are coagulation treatment, membrane treatment such as NF, RO, and the like. As a method of performing pigment removal more stably, a method of performing solid-liquid separation by a heating step of heating to 50 ° C or higher and a pH adjustment step of adjusting pH to 7 or less is proposed (Patent Document 5).

Patent Document 6 discloses that a negative organic polymer and a positive polymer are added to a drain containing a photoresist, and a negative organic polymer coagulant is added to perform solid-liquid separation treatment, and further biological treatment is required (No. 0009) , paragraphs 0010,0040).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Special Open 2007-29825

[Patent Document 2] Japanese Patent Laid-Open No. 6-55172

[Patent Document 3] Japanese Patent Laid-Open No. 8-155308

[Patent Document 4] Japanese Special Open 2003-39078

[Patent Document 5] Japanese Special Opening 2012-154994

[Patent Document 6] Japanese Special Open 2012-179529

[Non-patent literature]

[Non-Patent Document 1] Water Sci Tech 39, 10/11 189-192 (1989)

With the advancement of the color filter manufacturing technology in recent years, the fineness of the pigment and the increase in the dispersibility are very important from the efficient drainage of the drainage and the stable processing of the pigment component processing.

In particular, in the drainage treatment in which the composition is changed, there is no pre-pigment removal step, and it is difficult to maintain the treatment work stably in the subsequent steps. It is important that the previous treatment step removes the pigment component as much as possible.

As mentioned above, the color filter drainage system contains a high concentration of COD, and in order to reduce the load of the post-treatment step, the dissolved organic matter remaining after the removal of the pigment is also required to be removed as much as possible in the pretreatment step.

In the prior art, by the refinement of the pigment and the dispersibility, the increase in the amount of coagulation used in the coagulation treatment or the instability in the operation of the membrane occlusion is a problem. In Patent Document 5, since the pigment can be efficiently removed and the drainage is required to be heated, the operation cost is not necessarily inexpensive.

It is an object of the present invention to provide a method for treating development drainage in a color filter manufacturing step, which is capable of producing a color filter before the biological treatment or oxidation promotion treatment of the development drainage in the color filter production step. In the production step, the solid component or the dissolved matter in the development drainage is efficiently coagulated.

The method for treating development drainage in the color filter manufacturing step of the present invention, comprising the steps of: adding a acid to the development drainage in the color filter production step to adjust the pH to a pH adjustment step of pH 5 or less, and then adding The cation-based coagulant addition step of the cation-based coagulant, the cation-based coagulant addition step followed by the addition of the cation-based coagulant, and the solid-liquid separation step followed by solid-liquid separation.

In the above pH adjustment step, it is preferred to adjust the pH to pH 2 to 4.5.

It is preferred to add an inorganic coagulant between the pH adjustment step or between the pH adjustment step and the positive coagulant addition step, or between the positive coagulant addition step and the negative coagulant addition step.

The treated water from the solid-liquid separation step described above may also be subjected to biological treatment or oxidation-promoting treatment.

By adjusting the pH of the development drainage in the color filter production step to pH 5 or less, the dispersibility of the pigment particles dispersed in the drainage is lowered and coarsened, and the dissolved organic matter is not dissolved and precipitated as SS. In contrast to this insoluble treatment liquid, it is added after adding an inorganic coagulant as needed. A cationic coagulant, followed by a cation-based coagulant.

As such a polymer-based coagulant, first, a cationic coagulant is added, and the charged SS component in the solution for neutralizing the charge is coagulated. After the addition of the cation-based coagulant, the coagulated particles grow and coarsen depending on the cross-linking action. Then, the coagulation treatment liquid is treated by solid-liquid separation, and the pigment particles and the dissolved organic matter present in the development drainage in the color filter production step are sufficiently removed. Therefore, by subjecting the liquid after the solid-liquid separation treatment to biological treatment or oxidation-promoting treatment, it is possible to obtain treated water having high efficiency and high water quality.

1, 2, 3‧‧‧ stirring tank

4‧‧‧ Settling tank

Fig. 1a to Fig. 1c are flowcharts showing a method of treating development drainage in the color filter manufacturing step of the embodiment.

Fig. 2 is a flow chart showing a method of treating development drainage in the color filter manufacturing step of the comparative example.

Hereinafter, the present invention will be described in detail.

In the present invention, the color resist of the unexposed portion which occurs in the developing step of the color resist in the color filter manufacturing step (containing a pigment, an alkali-soluble resin, a photopolymerization component, a photopolymerization initiator, a dispersant, A solvent (such as a solvent) and a developing solution (a high-concentration nonionic surfactant and an alkali component are used as main components) are used as a main color filter development drainage to be treated. The COD _Cr is usually about 2,000 to 20,000 mg/L, and the pigment particles such as BM, RGB, RGBY, and CMY are contained in the COD _Cr of about 5 to 20%.

The raw water system usually exhibits an alkalinity of about pH 10 to 13 by containing an aqueous alkali solution as a developing solution. Moreover, the photoresist is generally alkali soluble. Therefore, in the present invention, the acid is added to the raw water to adjust the pH to pH 5 or lower, preferably to pH 2 to 4.5.

As the acid, sulfuric acid, hydrochloric acid or the like is suitable. By adjusting to pH 5 or less in this way, the pigment particles in the raw water are coarsened, and the dissolved organic matter is not dissolved. When M in the drainage, that is, when the alkalinity is high, aeration stirring is performed in the pH adjustment tank, and decarboxylation treatment may be performed.

Next, it is preferred to add an inorganic coagulant to the pH-adjusted liquid to further coarsen the pigment particles or the insoluble organic matter. As the inorganic coagulant, an iron-based coagulant such as ferric chloride or polyferric sulfate is preferred from the viewpoint of the set point of the coagulation pH, and the addition amount thereof is 200 to 5000 mg/L, especially 500~. About 2000mg/L is preferred. The addition of the above-mentioned acid can also be carried out simultaneously with the addition of the inorganic coagulant.

Next, a positive coagulant (organic polymer coagulant) is added to the liquid, and after stirring, a cation-based coagulant (organic polymer coagulant) is added, and after stirring, the particles in the liquid are coarsened. . The amount of the coagulant added is 5~50mg/L, especially about 10~20mg/L, and the dosage of the yin coagulant is 1~20mg/L, especially about 2~10mg/L. good.

The type of the coagulant and the cation-based coagulant is not particularly limited, and it is usually used by the user in the water treatment because of the salt concentration of the drainage. Highly, a high-salt type coagulant with a high coagulation effect is preferred.

Examples of the cationic coagulant include polyethyleneimine, ethylenediamine epichlorohydrin polycondensation, polyalkylenepolyamine, diallyldimethylammonium chloride or dimethylaminoethyl ( A quaternary ammonium salt of a methyl methacrylate is used as a polymer constituting a monomer, and examples of the cation-based coagulant include poly(meth)acrylic acid, poly(meth)acrylic acid, and (meth)acrylamide. a copolymer, a (meth) acrylamide ‧ 2-(meth) acrylamide-methyl sulfonic acid sulfonic acid copolymer, and the alkali metal salt.

The weight average molecular weight of the polymer coagulant is, for example, in the range of 500,000 to 30,000,000.

The time until the addition of the cation-based coagulant after adding the cation-based coagulant is 1 min or longer, for example, 1 to 20 min, especially 2 to 5 min. The addition of the inorganic coagulant may also be carried out between the cation-based coagulant addition step and the cation-based coagulant addition step.

After the above-mentioned cation-based coagulant is added, the stirred liquid is separated by solid-liquid separation. As the solid-liquid separation treatment, sedimentation separation, pressure flotation, membrane filtration, or the like can be employed.

As for the liquid after the solid-liquid separation treatment, post-treatment such as biological treatment or oxidation-promoting treatment is preferred. As the oxidation promoting treatment, ozone treatment, Fenton treatment, or the like can be employed.

[Examples]

The examples and comparative examples will be described below. In the following examples and comparative examples, a color filter developing drainage water having the following water quality was treated.

pH: 11.5

CODcr: 8000mg/L

TOC: 2700mg/L

BOD: 3500mg/L

As a cation coagulant, a polymer of chloromethane quaternary ammonium compound (DAM (CH ₃ Cl)) of dimethylamine ethyl methacrylate (weight average molecular weight of 9 million) was used as a cation-based coagulant, and sodium acrylate was used. (NaA) (weight average molecular weight 12 million).

[Example 1]

The above color filter development drainage is processed in accordance with the flow of Fig. 1a. That is, sulfuric acid was added to the color filter development drainage in the agitation vessel 1, and thus, as an inorganic coagulant, ferric chloride was added at 1000 ppm, and after stirring, it was set to pH 4.5. Next, 10 ppm of the coagulating agent was added to the stirring tank 2, and the mixture was rapidly stirred for 5 minutes, and then 5 ppm of the cation-based coagulant was added to the stirring tank 3, and the mixture was rapidly stirred for 3 minutes, followed by slow stirring 2 After a minute, solid-liquid separation was carried out in the sedimentation separation tank 4 to obtain treated water once.

Next, as the secondary treatment, the primary treated water was subjected to Fenton treatment as shown in Fig. 1b. Specifically, after adding sulfuric acid to the primary treatment water to set the pH to 3, ferrous sulfate 800 mg/L (as Fe) and hydrogen peroxide 8000 mg/L are added, and the pH is adjusted to pH 3 by sulfuric acid to cause the reaction 2 hour. Then, after the pH was adjusted to 11 by sodium hydroxide, sodium bisulfite was added as 2 times after the ORP (oxidation reductive potential) became 0 mV. Water. Table 1 shows the results of water quality measurement of the two treated waters.

[Embodiment 2]

In the first embodiment, the amount of ferrous sulfate added in the Fenton treatment was set to 1000 mg/L (as Fe), and the amount of hydrogen peroxide added was changed to 10000 mg/L, and the treatment was carried out under the same conditions. Table 1 shows the results of water quality measurement of the treated water twice.

[Comparative Example 1]

In the first embodiment, when the treatment was performed once, the treatment was carried out under the same conditions except that the male coagulant was not added as shown in Fig. 2 . Table 1 shows the results of water quality measurement of the treated water twice.

[Comparative Example 2]

In Comparative Example 1, the amount of ferrous sulfate added at the time of Fenton treatment was 1000 mg/L (as Fe), and the amount of hydrogen peroxide added was 10,000 mg/L, and the treatment was carried out under the same conditions. Table 1 shows the results of water quality measurement of the treated water twice.

[Comparative Example 3]

In Comparative Example 1, the pH of the tank 1 was changed to 6.5, and the treatment was carried out under the same conditions. Table 1 shows the results of water quality measurement of the treated water twice.

[Comparative Example 4]

In Comparative Example 3, the amount of ferrous sulfate added at the time of Fenton treatment was set to 1000 mg/L (as Fe), and the amount of hydrogen peroxide added was changed to 10000 mg/L, and the treatment was carried out under the same conditions. Table 1 shows the results of water quality measurement of the treated water twice.

[Comparative Example 5]

In Comparative Example 3, the addition amount of ferrous sulfate in the Fenton treatment was 1200 mg/L (as Fe), and the addition amount of hydrogen peroxide was 12000 mg/L, and the treatment was carried out under the same conditions. Table 1 shows the results of water quality measurement of the treated water twice.

As in Table 1, two treatment waters of good water quality were obtained by Examples 1 and 2.

Although the pH of the tank 1 was 4.5, and the comparative examples 1 and 2 in which no cation-based coagulant was added, the water quality of the treated water twice was slightly inferior. It is presumed that when only the cation-based coagulant is contained, the coagulation is not good, and the SS-containing organic substance is discharged.

In Comparative Examples 3 to 5 in which the pH of the tank 1 was 6.5, the water quality of the treated water twice was deteriorated unless the treatment (Fenton treatment) was performed twice as strongly as in Comparative Example 5.

[Example 3]

In the first embodiment, in place of the Fenton treatment, the treatment water was treated twice in the same manner as in the case of the aerobic biological treatment as shown in Fig. 1 (c), and the treatment was carried out under the same conditions. Table 2 shows the results of water quality measurement of the treated water twice. Further, the pH in the biological treatment tank was set to 7 ± 0.5, and the residence time was set to 24 hours.

[Comparative Example 6]

In Example 3, the treatment was carried out under the same conditions except that the male coagulant was not added as shown in Fig. 2 in the primary treatment. Table 2 shows the results of water quality measurement of the treated water twice.

[Comparative Example 7]

In Comparative Example 6, the treatment was carried out under the same conditions except that the pH of the tank 1 was adjusted to 6.5. Table 2 shows the results of water quality measurement of the treated water twice.

As in Table 2, the treated water of 2 times of good water quality was obtained by Example 3. When the positive coagulant was not added, or the comparative examples 6 and 7 in which the pH of the tank 1 was 6.5, the water quality of the secondary treated water deteriorated.

The present invention has been described in detail with reference to the particular embodiments of the invention.

The present application is based on Japanese Patent Application No. 2013-025718, filed on Jan.

1, 2, 3‧‧‧ stirring tank

4‧‧‧ Settling tank

Claims (4)

A method for treating development drainage of a color filter manufacturing step, comprising the steps of: adding a acid to a developing drainage in a color filter manufacturing step to adjust a pH to a pH adjustment step of pH 5 or less, and then A cation-based coagulant addition step of adding a cation-based coagulant, a cation-based coagulant addition step followed by addition of a cation-based coagulant, and a solid-liquid separation step followed by solid-liquid separation. The method for treating development drainage according to the color filter manufacturing step of claim 1 is to adjust the pH to pH 2 to 4.5 in the pH adjustment step. The method for treating development drainage according to the color filter manufacturing step of claim 1 or 2, which is in the foregoing pH adjustment step, or between the pH adjustment step and the positive coagulant addition step, or a mixed system An inorganic coagulant is added between the step of adding the coagulant and the step of adding the clinker coagulant. The method for treating development drainage of a color filter manufacturing step according to any one of claims 1 to 3, wherein the treated water from the solid-liquid separation step is subjected to biological treatment or oxidation-promoting treatment.