JP2730610B2 - Method for treating wastewater containing organic quaternary ammonium hydroxide - Google Patents

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 organic quaternary ammonium hydroxide-containing waste liquid, and more particularly, to a waste liquid containing organic quaternary ammonium hydroxide, which is mainly discharged from a developing process of semiconductor manufacturing. Accordingly, the present invention relates to a method for treating organic quaternary ammonium hydroxide-containing waste liquid which can efficiently and inexpensively remove these organic quaternary ammonium hydroxides.

[0002]

2. Description of the Related Art In recent years, with the development of electric and electronic technology, demand for semiconductor devices, printed circuit boards, liquid crystal display devices, and the like has increased, and accordingly, a developing solution used in a developing process after photoetching and a Si wafer have been developed. The amount of cleaning liquid used in the step of cleaning liquid crystal and glass substrates is increasing, and the amount of waste liquid discharged from the developing step and the cleaning step is also rapidly increasing. As for the developing solution and the cleaning solution used in such a developing step and a cleaning step, as the degree of integration of the semiconductor device increases, and as the pattern in a printed circuit board, a liquid crystal display device, and the like becomes finer, the purity thereof becomes higher. Is required. In order to cope with this high purification, for example, tetramethylammonium hydroxide (TMAH),
-Hydroxyethyltrimethylammonium (choline)
An aqueous solution of an organic quaternary ammonium hydroxide is frequently used.

[0003] For this reason, the waste liquid from such a developing step and the washing step usually contains organic quaternary ammonium hydroxide derived from the developer at a concentration of about 100 to 20,000 ppm. A resist stripping material derived from various photosensitive resins such as a used quinonediazide and phenol novolak resin mixture or condensate (photodegradable photoresist) is usually 10 to 1,000 ppm.
The organic quaternary ammonium hydroxide and the stripped resist are the main COD-causing substances. Therefore, to treat such waste liquid,
It is necessary to remove as much as possible the organic quaternary ammonium hydroxide and the resist stripping material as the COD-causing substances. Conventionally, neutralization and then microbial decomposition treatment are carried out, or combustion treatment is performed. The method was adopted.

[0004] However, the method of decomposing and discharging the microorganisms requires a large-scale activated sludge treatment facility, which requires a huge investment in waste liquid treatment, and also requires a large amount of investment in wastewater treatment. If organic quaternary ammonium is used, this activated sludge treatment is relatively effective, but TMA
In the case of a non-natural product such as H, this activated sludge treatment is impossible, or even if possible, the efficiency is extremely low in many cases, and there is a problem in economy and effectiveness itself. Regarding the method of combustion treatment, if waste liquid is directly burned in a combustion furnace, the equipment becomes large, and the combustion cost becomes too high. no way to, also, harmful NO _x is generated upon combustion, such equipment also need to remove the NO _x, there have been many problems.

To solve such a problem, Japanese Patent Laid-Open No. 60-118,282 discloses a method for solving the above problem.
A method has been proposed in which a waste liquid containing TMAH is supplied under pressure to a reverse osmosis membrane device under the condition of pH 9 to 12 to be concentrated and discharged as treated water having a low TMAH concentration or containing almost no TMAH. JP-A-60-24
No. 7,641 discloses that wastewater containing quaternary ammonium ions derived from TMAH or the like is concentrated by reverse osmosis filtration, the obtained concentrated water is electrolyzed, and the quaternary ammonium ions in the concentrated water are converted into quaternary ammonium ions. There has been proposed a method for recovering as a grade ammonium alkali. However, any of these methods basically uses an expensive reverse osmosis membrane and TM
AH is used to physically concentrate organic quaternary ammonium hydroxide such as AH, and in consideration of its durability, the pH range that can be used over a long period of time is actually about 10 or less. Since the pH rises as ammonium is concentrated, even when concentrated to a high concentration, TM
AH has a problem that it cannot be concentrated to a high concentration because it has a pH of 12 at a concentration of 0.02 mol / liter (0.2% by weight). Therefore, in order to avoid this problem, it is possible to neutralize the waste liquid in advance and perform reverse osmosis filtration.
In this case, there is a problem that the cost of the neutralizing agent is too high. In addition, in this reverse osmosis filtration, the concentration ratio that can be concentrated in one reverse osmosis filtration is as low as at most about 4 times, and therefore, in order to concentrate to a desired concentration, usually a plurality of reverse osmosis filtration operations are required. In addition, if the concentration of the waste liquid is not stable, there is a problem that a constant concentrated liquid cannot be obtained and it is difficult to use. Further, regarding such waste liquid, the contained T
Usually, the concentration of MAH or the like varies, and the method using reverse osmosis filtration has a problem that the concentration adjustment and the change of the operation conditions are inevitable every time. In addition, the resist stripping material contained in the waste liquid is also concentrated at the same time as the organic quaternary ammonium hydroxide, and it is thought that these are attached to the reverse osmosis membrane. And the life of the reverse osmosis membrane is short. Moreover, at present, there is no reverse osmosis membrane capable of completely removing solutes, and it is inevitable that organic quaternary ammonium hydroxide in a small amount of treated water leaks. There is also a problem that. For this reason, this method of reverse osmosis filtration requires a great deal of processing cost and has a problem that satisfactory results cannot always be obtained.

[0006]

Therefore, the present inventors efficiently and inexpensively treat at least such waste liquid containing organic quaternary ammonium hydroxide and discharge it as clean treated water with low COD. As a result of extensive research to establish a method for treating organic quaternary ammonium hydroxide-containing waste liquid that can be used, when such waste liquid is brought into contact with a cation exchanger, organic quaternary ammonium ions are selectively formed. In addition to being efficiently adsorbed by the cation exchanger, the organic quaternary ammonium hydroxide in the waste liquid can be efficiently removed. Have found that there is no problem, and completed the present invention. Therefore, an object of the present invention is to efficiently and inexpensively treat a waste liquid containing at least an organic quaternary ammonium hydroxide and to provide a waste liquid containing an organic quaternary ammonium hydroxide that can be discharged as clean treated water having a low COD. It is to provide a processing method. Further, another object of the present invention is to provide a wastewater containing at least an organic quaternary ammonium hydroxide and a resist stripping material efficiently and inexpensively, and can be discharged as clean treated water having a low COD. An object of the present invention is to provide a method for treating an organic quaternary ammonium-containing waste liquid.

[0007]

That SUMMARY OF THE INVENTION The present invention is
Derived from a developer and / or cleaning solution containing a distaste product
When treating a waste liquid containing at least an organic quaternary ammonium hydroxide, the waste liquid is contacted with a cation exchanger.
To make the organic quaternary ammonium ions adsorb on the cation exchanger, and then reprocess the obtained cation-exchanged water.
This is a method for treating organic quaternary ammonium hydroxide-containing waste liquid for separating and removing a resist stripping material . Further, the present invention provides a method for treating a quaternary ammonium hydroxide-containing waste liquid in which cation-exchanged water obtained by contacting the above cation exchanger with an acid is adjusted to pH 7 or less with an acid to separate and remove a resist stripped product. It is.

In the method of the present invention, the waste liquid to be treated is one containing mainly organic quaternary ammonium hydroxide as a COD-causing substance. Further, regarding this waste liquid, when the above-mentioned organic quaternary ammonium hydroxide is used as a developing solution or a cleaning solution, a resist stripping substance or other additive mixed into the developing solution or the cleaning solution, for example, various surfactants Other C, such as an agent or a small amount of alcohol or ether
It may contain an OD-causing substance. These other COD-causing substances pass through this cation exchanger without being chemically adsorbed to the cation exchanger, unless they are present as cations, and impede the adsorption of the organic quaternary ammonium hydroxide. do not become. However, when these other COD-causing substances are present in a large amount, the COD of the cation-exchanged water obtained by contact with the cation exchanger is reduced.
The value indicates a high value, and a treatment for removing these other COD causing substances such as an activated sludge treatment is required. In addition, for these waste liquids, COD-causing substances that do not exist as resist strips and other cations are removed.
For example, it may be a primary treatment liquid obtained by removing as much as possible in advance using activated carbon or the like. In such a case, by contacting with a cation exchanger, the liquid is sufficiently clean to be discharged as it is. Treated water.

Here, a typical waste liquid discharged from a developing step in the manufacture of a semiconductor device will be described. In the developing step, a single-wafer type automatic developing apparatus is often used.
In this apparatus, the step of using a developer and the subsequent rinsing (substrate cleaning) with pure water are performed in the same cup (tank),
At this time, in the rinsing step, since pure water is used in an amount of 5 to 10 times the amount of the developing solution, the developing solution used in the developing step is usually diluted to 5 to 10 times to become a waste liquid. For this reason, the composition of the waste liquid discharged in this development step is such that the organic quaternary ammonium hydroxide is about 1,000 to 5,000 ppm,
The resist peeling material is about 10 to 100 ppm, and the surfactant is about 0 to several tens ppm. Also,
When the organic quaternary ammonium hydroxide is tetramethylammonium hydroxide (TMAH), its concentration as a developer is usually around 2.3% by weight, so that the TMAH concentration in the waste liquid is usually 0.23%. % By weight.

The cation exchanger used in the present invention may be any as long as it can efficiently adsorb organic quaternary ammonium ions derived from organic quaternary ammonium hydroxide. Even if
It may be a strongly acidic cation exchanger. Then, the substrate of the ion exchanger may be an organic exchanger such as an ion-exchange resin, or may be an inorganic exchanger such as zeolite or silica gel. Any of granules, films, fibers and the like may be used. These cation exchangers include, for example, a combination of a weakly acidic cation exchanger and a strongly acidic cation exchanger, a combination of an inorganic exchanger and an organic exchanger, and a plurality of cation exchangers having different shapes. A plurality of cation exchangers can be appropriately combined and used in consideration of the type and properties of the waste liquid, the release after treatment with the cation exchanger, and the like. These cation exchangers are preferably granular weakly acidic cation exchange resins and / or strongly acidic cation exchange resins in view of their handling, economy, ion exchange capacity and the like.

Whether the cation exchanger is weakly acidic or strongly acidic is determined in consideration of the following advantages and disadvantages of the weakly acidic cation exchanger and the strongly acidic cation exchanger. After adsorbing organic quaternary ammonium ions on the cation exchanger, how to treat the cation exchanger adsorbing the organic quaternary ammonium ions and the cation exchange treated water that has passed through this cation exchanger It is better to select as appropriate depending on whether or not. [Advantages and disadvantages of weakly acidic cation exchanger and strongly acidic cation exchanger] The usable pH range is 4 for weakly acidic cation exchanger.
-14, and the strong acid cation exchanger is 0-14. The adsorption rate of organic quaternary ammonium ions is higher in the strongly acidic cation exchanger than in the weakly acidic cation exchanger. For neutral salts, strongly acidic cation exchangers have resolution, whereas weakly acidic cation exchangers have no resolution. Regarding the elution property of the adsorbed organic quaternary ammonium ion, in the case of a weakly acidic cation exchanger, it can be easily eluted using not only a strong acid but also a relatively weak acid such as carbonic acid or acetic acid as an eluent. It is possible and can be eluted with the use of relatively small amounts of acid. On the other hand, in the case of a strongly acidic cation exchanger, it is not easy to use a strong acid as an eluent, and in order to increase the elution rate, a large excess of strong acid exceeding 10 times that of organic quaternary ammonium ions is required. Must be used. Regarding the ion exchange capacity, generally, the weakly acidic cation exchanger is larger than the strongly acidic cation exchanger. When the organic quaternary ammonium salt aqueous solution collected by elution is electrolyzed to recover the organic quaternary ammonium hydroxide,
Although the free acid concentration increases in the latter half of the electrolysis step, if the eluent is a strong acid, a problem of corrosion of the electrolytic membrane or the electrode may occur. For this reason, for example, when an organic quaternary ammonium salt aqueous solution is eluted from a cation exchanger and this cation exchanger is repeatedly used, or an organic quaternary ammonium salt aqueous solution obtained by elution is electrolyzed. It is preferable to use a weakly acidic cation exchanger when recovering an organic quaternary ammonium, and when the organic quaternary ammonium salt is adsorbed or when the treatment needs to be performed in a short time, the adsorption speed is important. In cases where a problem occurs, it is preferable to use a strongly acidic cation exchanger.

Here, specific examples of the cation exchanger include polymers such as polystyrene, polyacrylic resin, polymethacrylic resin, and polytetrafluoroethylene;
A modified polymer obtained by modifying these polymers with a cross-linking agent such as divinylbenzene is used as a base, and a sulfonic acid group or a carboxylic acid group is introduced into the modified polymer to form a gel-type or porous-type cation exchange resin, zeolite, or the like. An inorganic cation exchanger such as silica gel may be used.

Further, as a method of the cation exchange treatment for bringing the waste liquid into contact with the cation exchanger, a conventionally known method can be appropriately employed depending on the type and shape of the cation exchanger. A column method in which a cation exchanger is filled in a column and a waste liquid is continuously passed, and a batch method in which a cation exchanger is added to the waste liquid and brought into contact with stirring, followed by filtration and solid-liquid separation, etc. Can be adopted.

[0014] The cation-exchanged water obtained by bringing the waste liquid into contact with the cation exchanger in this manner has organic quaternary ammonium ions in the waste liquid adsorbed by the cation exchanger and removed. By the way, when the waste liquid is, for example, derived from a developing solution, a resist stripping substance is present in the waste liquid, and the presence of the resist stripping substance impairs the adsorption of organic quaternary ammonium ions to the cation exchanger. Approximately the whole amount passes through this cation exchanger without being adsorbed by the cation exchanger, and remains in the cation-exchanged water. When the waste liquid is, for example, derived from a washing liquid, a surfactant is present in the waste liquid, and a part thereof is adsorbed at the beginning of contact with the cation exchanger. The presence of the agent does not hinder the adsorption of the organic quaternary ammonium ion to the cation exchanger.
Similarly, even when a small amount of alcohol or ether is present in the waste liquid, these alcohols or ethers pass through the cation exchanger without being adsorbed, remain in the cation exchange-treated water, and remain in the organic quaternary ammonium. Does not hinder the adsorption of ions to the cation exchanger. Therefore, for the cation-exchanged water obtained by contacting with the cation exchanger, the following treatment method is determined according to what kind of COD causing substance and how much, In general, the waste liquid generated in the developing step and the cleaning step for manufacturing semiconductor devices and liquid crystal devices is mainly a resist stripping material. In such a case, the cation-exchanged water is activated carbon-treated to remove the resist. Remove things,
Alternatively, by adjusting the pH to 7 or less with an acid, the stripped resist can be precipitated and separated and removed. If the surfactant remains, the surfactant is co-precipitated with the stripped resist. It can be separated and removed as much as possible.

Here, the acid used for pH adjustment for precipitating and separating and removing the resist stripped material and the surfactant is not particularly limited, but usually, an acid such as hydrochloric acid, nitric acid, sulfuric acid or the like is used. Acids, carbon dioxide, and organic acids such as acetic acid and formic acid are used, and inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid are preferable from the viewpoints of economy, handling, and not affecting the COD value. Regarding the pH value to be adjusted by this pH adjustment, the standard value in the national “Environmental Standard for Conservation of Living Environment” is pH 6.5 to 8.0.
Since it is 5, it is preferable to adjust the value so as to satisfy the reference value, so that the water can be discharged as it is after the filtration. The resist stripping substance precipitated by the pH adjustment as described above can be easily separated and removed by filtering the resist stripping substance.

The treated water obtained by removing the resist strips and the surfactant by the above pH adjustment usually has its COD value reduced to a level sufficient to be discharged as it is, so it is discharged as it is. be able to. However, if this treated water contains unacceptable COD-causing substances, such as alcohol and ether, which cannot be separated and removed by the activated carbon treatment or pH adjustment, activated sludge by microorganisms is necessary. After processing, etc., release. As the activated sludge treatment method in this case, a conventionally known method can be employed as it is, and in particular, an organic alkali such as organic quaternary ammonium hydroxide, a resist stripped product, or a surfactant is used as much as possible. Because of the separation and removal, the load of this activated sludge treatment is usually extremely small, and clean treated water can be easily obtained. Further, the resist stripped material and the surfactant that are separated and removed by the pH adjustment and thus collected are burned or treated as industrial waste. Furthermore, the cation exchanger used in the cation exchange treatment is usually
It is treated with an eluent comprising an aqueous acid solution to elute and remove organic quaternary ammonium ions and the like adsorbed on the cation exchanger, and is used again in the cation exchange treatment.

The organic quaternary ammonium ion adsorbed on the cation exchanger in the cation exchange treatment is as follows:
If necessary, this organic quaternary ammonium ion is eluted using an eluent composed of an aqueous acid solution, and is recovered as an organic quaternary ammonium salt aqueous solution. The aqueous solution of the organic quaternary ammonium salt thus recovered is a salt in which the organic quaternary ammonium hydroxide in the waste liquid is concentrated to a high concentration, and may be incinerated as it is. Alternatively, the organic quaternary ammonium salt aqueous solution can be electrolyzed by an electrolytic cell using a cation exchange membrane as a diaphragm, and can be recovered as a useful organic alkali, that is, organic quaternary ammonium hydroxide.

When useful organic quaternary ammonium hydroxide is recovered from the waste liquid, an aqueous acid solution is used as an eluent, and the acid is liberated in the step of electrolyzing the aqueous quaternary ammonium salt solution. It is preferable to recover the organic quaternary ammonium hydroxide by carrying out electrolysis while circulating and using the acid liberated in the electrolysis step as an eluent and eluting the organic quaternary ammonium ions adsorbed on the cation exchanger. This makes it possible to elute the organic quaternary ammonium ion adsorbed on the cation exchanger by using a small amount of acid, and eliminates the problem of corrosion of the electrolytic membrane and the electrode due to the low concentration of the acid aqueous solution used. Moreover, the released acid can be prevented as much as possible from entering the organic quaternary ammonium hydroxide aqueous solution collected through the electrolytic membrane as an impurity, and a high-purity organic quaternary ammonium hydroxide aqueous solution can be recovered. The acid used for this purpose is not particularly limited, and inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, and inorganic acids such as carbonic acid, and organic acids such as acetic acid and formic acid can be used. A non-electrolytic acid that does not generate any gas and that can be used repeatedly without being consumed is preferable, and from the viewpoint of recovering high-purity organic quaternary ammonium hydroxide among others, more preferably carbonic acid, The sulfuric acid has a low concentration of about 0.05 to 2.0% by weight.

[0019]

According to the method of the present invention, at the time of treating a waste liquid containing at least an organic quaternary ammonium hydroxide, the waste liquid is brought into contact with a cation exchanger so that organic quaternary ammonium ions can be reliably exchanged with a cation. Since the organic quaternary ammonium hydroxide is adsorbed on the body, the organic quaternary ammonium hydroxide can be efficiently and reliably removed regardless of the concentration of the organic quaternary ammonium hydroxide in the waste liquid. In addition, even when the resist stripping material of the polymer substance is present in the waste liquid, the resist stripping material adheres to the cation exchanger during the cation exchange treatment, and the performance of the cation exchanger is reduced. Without degradation
The organic quaternary ammonium hydroxide can be efficiently and reliably removed, and a large amount of waste liquid can be treated using a small amount of a cation exchanger. In addition, resist strips and surfactants remaining in the cation exchange water after passing through the cation exchanger can be easily separated and removed by adjusting the pH of the cation exchange water to 7 or less with an acid. In addition, the pH adjustment at this time can be performed very easily because organic quaternary ammonium ions showing alkalinity are adsorbed on the cation exchanger side by the cation exchange treatment.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. Using a photo-decomposable resist (trade name: OFPR8800, manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a resist, and using a TMAH aqueous solution of 0.261 mol / l as a developing solution, a waste liquid [pH] generated in a developing process of semiconductor device manufacturing. : 1
2, TMAH: 2,000 ppm, stripped resist: 3
8 ppm, nonionic surfactant: 46.9 dyne /
cm], and the waste liquid according to the following example was treated.

Example 1 As a cation exchanger, 200 ml of a weakly acidic cation exchange resin (trade name: C-464, manufactured by Sumitomo Chemical Co., Ltd.) was used for a length of 30.
A column of 0 mm × 60 mm in diameter was packed to prepare an ion exchange resin column. 10 liters of the above waste liquid was passed through the ion exchange resin column at a liquid flow rate of 30 ml / min, and the waste liquid was subjected to a cation exchange treatment. The cation-exchanged water obtained by this cation-exchange treatment is measured for TMAH concentration by neutralization titration, resist stripper concentration by absorptiometer, and surface tension by surface tension meter to measure surface activity. The agent concentrations were measured respectively. Table 1 shows the results.

Next, a 0.1 mol / l sulfuric acid aqueous solution was added to 10 liters of the cation exchange-treated water thus obtained.
0 ml was added, and the pH of the treated water was adjusted to 6.5. Due to this pH adjustment, the resist stripped product and the surfactant precipitated, and these were separated by filtration and removed. After the pH was adjusted, the treated water obtained by filtration was measured for its TMAH concentration, resist stripped material concentration, and surfactant concentration as indicated by surface tension. Table 1 shows the results.

[0023]

[Table 1] As is evident from Table 1, the treated water obtained by filtration after pH adjustment has a COD value of only 5 mg / l, and can be sufficiently discharged without requiring activated sludge treatment. It was clean.

Also, 500 ml of a 0.31 mol / l sulfuric acid aqueous solution was used as an eluent, and tetramethylammonium ion (TMA ion) adsorbed on the cation exchange resin by the above cation exchange treatment was removed from the cation exchange resin. After elution, 500 ml of a 0.218 mol / l aqueous solution of TMA sulfate was recovered. The 0.2 thus obtained
500 ml of an 18 mol / l aqueous solution of TMA sulfate are then circulated at a flow rate of 100 ml / min into the anode chamber of an electrolytic cell using a cation exchange membrane as a membrane, and 0.05 mol / l of TMAH is introduced into the cathode chamber. The flow rate of the aqueous solution is 100 ml /
Minutes, and a voltage of 9 to 17 is applied between the anode and the cathode.
V, a DC current of about 2 A is applied, and electrolysis is performed for about 11 hours.
500 ml of a 0.355 mol / l TMAH aqueous solution was recovered. The TMAH recovery rate with respect to TMAH present in the waste liquid was about 75% by weight, and 0.355 mol /
1 of the TMAH aqueous solution was as pure as the impurity concentration in the TMAH aqueous solution used as the developing solution.

Example 2 Instead of a weakly acidic cation exchange resin, a strongly acidic cation exchange resin [trade name of Mitsubishi Kasei Co., Ltd.] was used as a cation exchanger.
SK-112] 500 ml with a length of 300 mm and a diameter of 80
The column was packed in an mm-size column to prepare an ion-exchange resin column. A liquid flow rate of 25 ml /
The waste liquid was passed through 50 liters at a speed of one minute, and the waste liquid was subjected to a cation exchange treatment. Example 1 of the cation exchange treated water obtained by this cation exchange treatment
In the same manner as in the above, the TMAH concentration, the resist stripped material concentration, and the surfactant concentration indicated by the surface tension were measured. Table 2 shows the results.

Next, 10 ml of a 0.1 mol / l aqueous sulfuric acid solution was added to 10 liters of the cation exchange-treated water thus obtained, and the pH of the treated water was adjusted to 6.5. . Due to this pH adjustment, the resist stripped product and the surfactant precipitated, and these were separated by filtration and removed. This p
The HMA was adjusted and the treated water obtained by filtration was treated with its TMA.
The H concentration, the resist stripping material concentration, and the surfactant concentration indicated by surface tension were measured. Table 2 shows the results.

[0027]

[Table 2] As is clear from Table 2, the treated water obtained by filtration after pH adjustment has a COD value of only 6 mg / l, and is sufficiently large to be able to be discharged without requiring activated sludge treatment. It was clean.

Further, 0.05 mol / l as an eluent was added to the cation exchange resin to which tetramethylammonium ion (TMA ion) was adsorbed by the above cation exchange treatment.
The sulfuric acid aqueous solution of 200 ml was supplied, and the eluate passed through the cation exchange resin was then circulated at a flow rate of 200 ml / min into the anode chamber of an electrolytic cell using a cation exchange membrane as a membrane. A 0.06 mol / l TMAH aqueous solution was circulated in the cathode chamber of the cell at a flow rate of 200 ml / min, and a DC current of 25 to 50 V and a current of about 2.5 A was passed between the anode and the cathode to elute. While performing electrolysis for about 25 hours, 1,100 ml of a TMAH aqueous solution was recovered. The TMAH recovery rate for the TMAH present in the waste liquid is about 65
%, And the recovered TMAH aqueous solution was 0.65 mol /
and the purity was as high as that of the TMAH aqueous solution used as the developing solution.

Example 3 As a cation exchanger, 50 ml of a strongly acidic cation exchange resin (PK216H, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) having a length of 300
A column having a size of 20 mm and a diameter of 20 mm was packed to prepare a cation exchange resin column. Waste liquid [TMAH500p] was passed through this cation exchange resin column at a liquid flow rate of 20 ml / min.
pm (0.005 mol / l)], resist stripping 10p
pm, a surfactant of 58.4 dyne / cm] 16 liters, and the cations in the waste liquid were adsorbed on the cation exchange resin. Thereafter, 150 ml of a 0.5 mol / l sulfuric acid solution was passed through the cation exchange resin column to elute cations adsorbed on the cation exchange resin. The volume of the obtained eluent was 0.15 liter,
6 liters could be concentrated about 106 times. At this time, the recovery rate of TMAH was 84.2%.
The TMAH recovery rate was determined by measuring the TMA ion concentration in the TMA sulfate in the obtained eluate by anion exchange separation-neutralization titration.
H was calculated. As is apparent from the third embodiment, the volume of the waste liquid can be reduced to about 1/100, and the waste liquid can be concentrated to a high concentration to significantly reduce the cost for the combustion treatment and the industrial waste treatment.

[0030]

According to the method of the present invention, at the time of treating a waste liquid containing at least an organic quaternary ammonium hydroxide, it is possible to efficiently and surely hydroxylate the waste liquid regardless of the concentration of the organic quaternary ammonium hydroxide in the waste liquid. The organic quaternary ammonium can be removed, and even if a resist stripping substance of a high molecular substance exists in the waste liquid, the resist stripping substance or the like becomes a cation exchanger during the cation exchange treatment. Adhesion does not deteriorate the performance of the cation exchanger, and a large amount of waste liquid can be treated using a small amount of the cation exchanger. For this reason, even wastewater containing organic quaternary ammonium hydroxide, which is difficult to treat with activated sludge, is efficiently and inexpensively treated to reduce CO2.
Clean treated water with low D can be obtained.

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Claims (4)

(57) [Claims] 1. A developing solution containing a resist stripping material and / or
Or , when treating the waste liquid containing at least the organic quaternary ammonium hydroxide derived from the washing liquid, contacting the waste liquid with a cation exchanger to adsorb the organic quaternary ammonium ions to the cation exchanger , and then obtaining Cation
A method for treating an organic quaternary ammonium hydroxide-containing waste liquid, wherein the exchange treatment water is re-treated to separate and remove a resist stripping product . 2. The organic quaternary ammonium hydroxide-containing solution according to claim 1, wherein the re-treatment of the cation-exchange treated water is carried out by adjusting the pH of the cation-exchange treated water to 7 or less with an acid to separate and remove the resist stripped product. Waste liquid treatment method. 3. The method for treating wastewater containing organic quaternary ammonium hydroxide according to claim 1 , wherein the cation exchanger is a weakly acidic cation exchange resin. 4. The method for treating waste water containing organic quaternary ammonium hydroxide according to claim 1 , wherein the cation exchanger is a strongly acidic cation exchange resin.