JP2010125352A - Treatment system for waste water generated in photoresist development - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a treatment system for waste water generated in photoresist development, in which an organic fluorine compound in waste water generated in photoresist development is efficiently removed. <P>SOLUTION: The waste water treatment system is provided with: a pretreatment apparatus which reduces the content ratio expressed by tetraalkylammonium hydroxide/organic fluorine compound (by mass ratio) in waste water generated in photoresist development, containing an organic fluorine compound and tetraalkylammonium hydroxide; an anion exchange tower 30 filled with an ion exchanger including an anion exchanger; and a means of allowing water treated by the pretreatment apparatus to flow to the anion exchange tower 30. The pretreatment apparatus may be an electrodialyzer 20, may be a membrane separator or may be a cation exchange tower filled with an ion exchanger including a cation exchanger. The system is preferably provided with: a means of allowing a regenerated liquid to flow to the anion exchange tower 30; and a decomposition apparatus 100 for decomposing the regenerated liquid circulated through the anion exchange tower 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wastewater treatment system for photoresist development wastewater.

  Conventionally, in the field of LSI manufacturing and the like, as a method of forming a high-definition pattern, pattern exposure is performed on a photoresist layer applied on a substrate, and after exposure, the photoresist is developed and further etched. 2. Description of the Related Art A pattern molded body is manufactured by photolithography, such as directly forming a target pattern by exposing a photoresist.

  Since photolithography has excellent properties in terms of heat resistance and chemical resistance, organic fluorine compounds have been used for applications such as surfactants. Since organic fluorine compounds are chemically stable, they are difficult to be decomposed by microorganisms. For example, organic fluorine compounds such as perfluorooctane sulfonic acid (PFOS), perfluoroalkyl sulfonic acid (PFAS), and perfluorooctanoic acid (PFOA) are not retained in the environment because they do not decompose in the ecosystem. Therefore, it is desired to detoxify the organic fluorine compound by decomposing it.

In general, as a method for removing organic substances in waste water, a method using a Fenton reagent, a method using ozone, a method using hydrogen peroxide and ultraviolet rays, and the like can be given. However, since these treatment methods have low oxidizing ability, it is not possible to effectively decompose chemically stable organic fluorine compounds. In addition, since organic fluorine compounds are chemically stable, a high temperature of about 1000 ° C. or higher is required for thermal decomposition by incineration. Further, for example, there is an adsorption removal method using an ion exchanger or activated carbon as a method for purifying water by removing organic substances in water (for example, Patent Document 1). Further, Patent Document 1 proposes a method of oxidizing and decomposing an organic substance adsorbed and removed by an ion exchanger under supercritical conditions. In such oxidative decomposition, a hardly decomposable organic substance that could not be decomposed / removed by a conventional wastewater treatment method can be decomposed.
Japanese Patent Laid-Open No. 2006-6997

However, in the photoresist development wastewater, other chemicals used in the photolithography process, for example, tetramethylammonium hydroxide (TMAH) used as a developer, tetraalkylammonium hydroxide (TAAH) such as choline, etc. Are often included as tetraalkylammonium (TAA) ions. In addition, the concentration of the organic fluorine compound in the photoresist development waste water is a low concentration of several μg / L to several hundred μg / L. For this reason, when the photoresist development waste water is simply brought into contact with the ion exchanger, there is a problem that the removal efficiency of the organic fluorine compound is low.
Accordingly, an object of the present invention is to provide a wastewater treatment system for photoresist development wastewater that can efficiently remove organic fluorine compounds in the photoresist development wastewater.

  The wastewater treatment system for photoresist development wastewater of the present invention reduces the content ratio represented by tetraalkylammonium hydroxide / organic fluorine compound (mass ratio) in photoresist development wastewater containing an organic fluorine compound and tetraalkylammonium hydroxide. A pretreatment device, an anion exchange column filled with an ion exchanger including an anion exchanger, and means for flowing water treated by the pretreatment device to the anion exchange column. The pretreatment device may be an electrodialysis device, a membrane separation device, or a cation exchange column packed with an ion exchanger containing a cation exchanger. Furthermore, it is preferable to have a means for flowing the regenerated solution to the anion exchange column and a decomposition device for decomposing the regenerated solution that has flowed through the anion exchange column. More preferably, it is a critical water oxidation apparatus.

  According to the waste water treatment system for photoresist development waste water of the present invention, the organic fluorine compound in the photoresist development waste water can be efficiently removed.

  Hereinafter, although the waste water treatment system of the present invention will be described with an example, it is not limited to this embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of a photoresist development wastewater treatment system 10 (hereinafter sometimes simply referred to as a wastewater treatment system) 10 according to the first embodiment. As shown in FIG. 1, the wastewater treatment system 10 includes an electrodialysis apparatus 20 that is a pretreatment apparatus and an anion exchange tower 30.

  A pipe 203, a pipe 205, a pipe 213, and a pipe 215 are connected to the electrodialysis apparatus 20. The pipe 203 is connected to the desalted water tank 202 via a desalted water pump 204. A pipe 205 is connected to the desalted water tank 202. Thus, the electrodialyzer 20, the pipes 203 and 205, the desalted water pump 204, and the desalted water tank 202 constitute a desalted water circulation line 206. A drainage supply line 21 and a pretreatment water outflow line 23 are connected to the desalted water tank 202. The drainage supply line 21 is connected to a drainage supply source (not shown). The pretreatment water outflow line 23 is connected to the anion exchange tower 30 via the valve 22. The pipe 213 is connected to the concentrated water tank 210 via the concentrated water pump 214. A pipe 215 is connected to the concentrated water tank 210. Thus, the concentrated water circulation line 216 is configured by the electrodialyzer 20, the pipes 213 and 215, the concentrated water pump 214, and the concentrated water tank 210. A concentrated water drain line 217 is connected to the concentrated water tank 210, and the concentrated water drain line 217 is connected to a concentrated water drain port (not shown).

  The pretreatment water outflow line 23 is provided with a valve 22, and a regenerated liquid supply line 41 is connected to a position between the anion exchange tower 30 and the valve 22. The regeneration liquid supply line 41 is connected to the regeneration liquid tank 40, and the regeneration liquid supply line 41 is provided with a regeneration pump 42. A first treated water outflow line 31 is connected to the anion exchange tower 30, and the first treated water outflow line 31 is connected to a first drain outlet (not shown). The first treated water outflow line 31 is provided with a valve 32, and the regenerated waste liquid inflow line 101 is connected to a position between the anion exchange tower 30 and the valve 32. The regeneration waste liquid inflow line 101 is provided with a valve 102, and the regeneration waste liquid inflow line 101 is connected to the decomposition apparatus 100. The decomposition apparatus 100 is connected to a second drain port (not shown) by a second treated water outflow line 103. The “means for flowing the water treated by the pretreatment apparatus to the anion exchange tower” includes a pretreatment water outflow line 23, a valve 22, and a desalted water tank 202. The “means for flowing the regenerated liquid to the anion exchange tower” includes the pretreatment water outflow line 23, the regenerated liquid tank 40, the regenerated liquid supply line 41, and the regenerating pump 42.

  As the electrodialysis apparatus 20, a known apparatus can be used. For example, a demineralization chamber partitioned by a cation exchange membrane arranged on the cathode side and an anion exchange membrane arranged on the anode side is provided between the cathode and the anode arranged opposite to each other, One having a concentrating chamber on both sides of the chamber. In the electrolysis apparatus 20, by applying a DC voltage to the cathode and the anode, the ion component contained in the water flowing through the desalting chamber is attracted to the counter electrode side, and is allowed to pass through the cation exchange membrane or the anion exchange membrane. Ingredients can be transferred to the concentration chamber.

  The anion exchange tower 30 is filled with an ion exchanger including an anion exchanger. As the ion exchanger packed in the anion exchange tower 30, for example, an ion exchange resin, an ion exchange fiber, a monolithic porous ion exchanger, or the like can be used. Of these, the most general-purpose ion exchange resin is preferably used.

  Examples of the anion exchanger are those capable of removing organic fluorine compounds such as PFOS, PFAS, and PFOA contained in the photoresist development waste water, and examples thereof include strong basic anion exchangers and weak basic anion exchangers. Examples of the anion exchanger include amberlite (trade name, manufactured by Rohm and Haas) which is an anion exchange resin.

  The anion exchanger is not particularly limited from the viewpoint of the type of the regenerating solution, and may be an anion exchanger that is regenerated with an alkaline aqueous solution such as sodium hydroxide, or may be regenerated with hot water. Generally, an alkaline aqueous solution such as sodium hydroxide is used for the regeneration of the anion exchanger. However, when the regeneration waste liquid is treated by the supercritical water oxidation treatment described later, there is a concern about the corrosion of the supercritical water oxidation apparatus by the alkaline aqueous solution. For this reason, it is necessary to select materials for constituent members of the supercritical water oxidation apparatus, relax operating conditions, and the like. Further, when the regenerated waste liquid is neutralized, there is a concern of clogging due to salt precipitation in the supercritical water oxidation apparatus. As described above, the use of an alkaline aqueous solution as the regenerating solution limits the device design and operating conditions. Therefore, an anion exchanger that can be regenerated with hot water is preferable, but not limited thereto.

  The filling form of the ion exchanger of the anion exchange tower 30 can be determined in consideration of the water quality of the photoresist developing wastewater, etc., and the single bed form filled with the anion exchanger alone, the cation exchanger and the anion exchanger And a mixed bed form in which cation exchanger packed bed and anion exchanger packed bed are stacked in the vertical direction. Among these, from the viewpoint of efficiently removing the organic fluorine compound in the photoresist development waste water, a single-bed form of the anion exchanger is preferable. In addition, in the case of the mixed bed form of the cation exchanger and the anion exchanger or the double bed form, the ratio of the anion exchanger in the ion exchanger packed in the anion exchange tower 30 is 50 volume% or more and 100 volumes. It is preferable to make it less than%.

  The cation exchanger to be packed in the anion exchange tower 30 can be determined in consideration of the water quality of the photoresist development waste water and the like, and examples thereof include a strong acid cation exchanger and a weak acid cation exchanger. Examples of the cation exchanger include amberlite (trade name, manufactured by Rohm and Haas) which is a cation exchange resin.

  Examples of the decomposition apparatus 100 include a supercritical water oxidation apparatus and an incineration apparatus. Among these, it is preferable to use a supercritical water oxidation apparatus that can perform a treatment at a relatively low temperature and has a small environmental load for increasing the temperature. A supercritical water oxidation apparatus is an apparatus that oxidizes and decomposes organic substances using high reactivity of supercritical water. A supercritical water oxidation apparatus as the decomposition apparatus 100 will be described with reference to FIG. As shown in FIG. 2, the decomposition apparatus 100 includes a reactor 120, a cooler 130, and a decompressor 140. A piping 111 and an oxidant supply line 113 are connected to the reactor 120. The pipe 111 is connected to the recycled waste liquid inflow line 101 via the high-pressure pump 110, and the oxidant supply line 113 is connected to the oxidant supply source 112 via the oxidant pump 114. The reactor 120 is connected to the cooler 130 by a pipe 121. The cooler 130 is connected to the decompressor 140 by a pipe 131. A second treated water outflow line 103 is connected to the decompressor 140.

  An example of the reactor 120 is a reactor (batch type) in which a heater or the like is provided on the outer periphery of a container having heat resistance and pressure resistance. Alternatively, there may be mentioned those in which a heater or the like is provided on the outer periphery of a cylindrical pipe or a coiled tube (continuous type). In the batch type, it is necessary to increase the size of the reactor 120 in accordance with an increase in the processing amount of the photoresist developing waste water. For this reason, it is preferable to use a continuous reactor 120 from the viewpoint of efficiently processing a large amount of photoresist development waste water.

  The cooler 130 is not particularly limited as long as it can cool the water heated to a high temperature (374 ° C. or higher) to a supercritical state in the reactor 120 to an arbitrary temperature, and can be converted into a liquid. Etc. can be used.

  The decompressor 140 is not particularly limited as long as it can depressurize the water at a high pressure (22 MPa or more) in order to bring the reactor 120 into a supercritical state, and a valve type, a capillary type, or the like is used. Can do.

  A method for treating photoresist development waste water using the waste water treatment system 10 will be described with reference to FIGS. First, the valves 22, 32, and 102 are closed, the desalted water pump 204 and the concentrated water pump 214 are started, and the regeneration pump 42, the pressurizing pump 110, and the oxidant pump 114 are stopped. Photoresist development wastewater is supplied to a desalted water tank 202 from a wastewater supply source. Next, the photoresist development wastewater is also stored in the concentrated water tank 210 as concentrated water, and the concentrated water in the concentrated water tank 210 is supplied to the concentrating chamber of the electrodialyzer 20 via the pipe 213 and flows through the concentrating chamber. The concentrated water is returned to the concentrated water tank 210 through the pipe 215 and circulated. A DC voltage is applied between the cathode and the anode of the electrodialyzer 20. The water in the desalting water tank 202 is supplied to the desalting chamber of the electrodialyzer 20 through the pipe 203, and the water flowing through the desalting chamber is returned to the desalting water tank 202 through the pipe 205 and circulated.

In the photoresist developing wastewater that has flowed into the electrodialyzer 20, TAAH is dissociated into TAA ions as the cation component and OH ⁻ as the anion, so the TAA ions are attracted to the cathode that is the counter electrode, and the cation exchange membrane Is transferred to the concentration chamber and taken into the concentrated water. On the other hand, OH ⁻ is attracted to the anode, which is the counter electrode, passes through the anion exchange membrane, moves to the concentration chamber, and is taken into the concentrated water. As described above, the photoresist developing wastewater stored in the desalted water tank 202 mainly removes cation components such as TAA ions and OH ⁻ . On the other hand, the organic fluorine compound in the photoresist development wastewater does not move to the concentration chamber of the electrodialysis apparatus 20 because it has a high molecular weight and is difficult to permeate the anion exchange membrane, and circulates in the desalted water circulation line 206. Thus, the photoresist development wastewater in the desalted water tank 202 becomes pretreated water from which TAAH has been removed and TAAH / organic fluorine compound (mass ratio) has been reduced (pretreatment step).

  After performing the pretreatment process for an arbitrary period, the valves 22 and 32 are opened, the valve 102 is closed, the desalted water pump 204, the concentrated water pump 214, the regeneration pump 42, the pressurizing pump 110, and the oxidizing agent pump. In a state where 114 is stopped, the pretreated water in the desalted water tank 202 is caused to flow from the pretreated water outflow line 23 to the anion exchange tower 30. The pretreatment water that has flowed into the anion exchange tower 30 flows while diffusing through the anion exchanger filled in the anion exchange tower 30, and flows out from the first treated water outflow line 31. During this time, the organic fluorine compound in the pretreated water comes into contact with the anion exchanger, dissociates in water, and becomes an ionized organic fluorine compound ion. And the organic fluorine compound ion which is an anion component is adsorbed by the anion exchanger and removed from the pretreated water. Thus, the pretreated water becomes the first treated water from which the organic fluorine compound has been removed, and flows to the first drain through the first treated water outflow line 31 (drainage purification step).

  After performing the above-described drainage purification process for an arbitrary period, the valve 102 is opened and the valves 22 and 32 are closed. Then, the desalted water pump 204 and the concentrated water pump 214 are stopped, the regeneration pump 42, the pressurizing pump 110, and the oxidant pump 114 are activated, and the regeneration liquid in the regeneration liquid tank 40 is supplied from the regeneration liquid supply line 41. It flows through the pretreatment water outflow line 23 to the anion exchange tower 30. The regenerated liquid that has flowed into the anion exchange tower 30 flows while diffusing through the anion exchanger filled in the anion exchange tower 30. During this time, the organic fluorine compound ions adsorbed on the anion exchanger are desorbed and taken into the regenerating solution. Then, the regenerated liquid (regenerated waste liquid) incorporating the organic fluorine compound ions flows out from the anion exchange tower 30 to the first treated water outflow line 31 (regeneration process).

  Next, the recycled waste liquid flows into the decomposition apparatus 100 through the first treated water discharge line 31 and the recycled waste liquid inflow line 101 in order. The regenerated waste liquid that has flowed into the decomposition apparatus 100 is pressurized to an arbitrary pressure by the pressure pump 110 and flows into the reactor 120 via the pipe 111. In addition, the oxidizing agent pump 114 supplies the oxidizing agent in the oxidizing agent tank 112 to the reactor 120 from the oxidizing agent supply line 113. Next, the temperature inside the reactor 120 is raised to an arbitrary temperature, and the water of the regeneration waste liquid in the reactor is brought into a supercritical state. In this way, when the recycled wastewater is brought into a supercritical state in the presence of an oxidizing agent, the organic fluorine compound contained in the recycled wastewater is oxidatively decomposed into hydrofluoric acid, carbon dioxide, water, etc. due to oxidation in supercritical water. And detoxified (supercritical water oxidation treatment). The regenerated waste liquid obtained by oxidizing and decomposing organic fluorine compound ions is cooled to an arbitrary temperature by the cooler 130 and liquefied, and then adjusted to an arbitrary pressure by the decompressor 140. Thus, the regenerated waste liquid is rendered harmless, becomes second treated water containing exhaust gas such as carbon dioxide and hydrofluoric acid, and flows from the second treated water outflow line to the second drainage port (recycled liquid purification step).

  The photoresist developing waste water means all water discharged from the photolithography process, and contains an organic fluorine compound and TAAH. Examples of the organic fluorine compound in the photoresist development waste water include PFOS, PFAS, and PFOA. Although the density | concentration of the organic fluorine compound in a photoresist image development waste_water | drain is not specifically limited, For example, it is preferable that it is 0.1-1000 microgram / L. This is because the effects of the present invention are remarkably exhibited within the above range.

  In addition, as TAAH contained in the photoresist development waste water, for example, TMAH, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, methyltriethylammonium hydroxide, trimethylethylammonium hydroxide, dimethylhydroxide Diethylammonium, trimethyl (2-hydroxyethyl) ammonium hydroxide (ie, choline), triethyl (2-hydroxyethyl) ammonium hydroxide, dimethyldi (2-hydroxyethyl) ammonium hydroxide, diethyldi (2-hydroxyethyl) hydroxide Ammonium, methyl tri (2-hydroxyethyl) ammonium hydroxide, ethyl tri (2-hydroxyethyl) ammonium hydroxide, tetra (2-hydroxyethyl) ammonium hydroxide Beam, and the like. The TAAH concentration in the photoresist development wastewater is not particularly limited, but is preferably 500 to 20000 mg / L, for example. This is because when the TAAH concentration in the photoresist developing wastewater is within the above range, the effects of the present invention are remarkably exhibited.

  The TAAH / organofluorine compound (mass ratio) in the pretreatment water can be determined according to the type of anion exchanger packed in the anion exchange tower 30. For example, the TAAH / organic fluorine compound (mass ratio) is preferably 10000/1 or less, more preferably 1000/1 or less, and even more preferably 100/1 or less. This is because the removal efficiency of the organic fluorine compound in the anion exchange tower 30 can be improved by reducing the relative concentration of TAAH to the organic fluorine compound in the pretreated water.

  The concentration of the organic fluorine compound in the pretreated water can be determined according to the type of anion exchanger packed in the anion exchange tower 30, and is preferably 0.1 to 1000 μg / L, for example. This is because the organic fluorine compound can be satisfactorily removed in the anion exchange tower 30 within the above range.

  The TAAH concentration in the pretreated water can be determined in consideration of the amount of treated water required for the waste water treatment system 10, the capacity of the anion exchange tower 30, and the like, and is preferably less than 500 mg / L, for example, 200 mg / L is more preferable. This is because the removal of the organic fluorine compound removal efficiency by the anion exchange tower 30 can be prevented by removing TAAH in the pretreated water as much as possible.

The amount of pretreated water flowing into the anion exchange tower 30 can be determined in consideration of the concentration of the organic fluorine compound in the pretreated water and the type of ion exchanger packed in the anion exchange tower 30. The liquid flow rate to the anion exchange column 30 is represented by space velocity (SV), and the unit of SV is the flow rate (L) that is circulated in one hour with respect to the unit volume (L) of the ion exchanger. ^-Represented by h- ¹ (the same applies hereinafter) For example, in this embodiment, it is preferable to determine in the range of SV = 5 to 200 L / L · h ⁻¹ . This is because if the SV is too high, the removal of the organic fluorine compound in the pretreatment water may be insufficient, and if the SV is too low, the treatment capacity of the wastewater treatment system 10 is reduced.

  The regenerating solution can be determined according to the type of anion exchanger packed in the anion exchange tower 30, and examples thereof include alkaline aqueous solutions such as sodium hydroxide aqueous solution and potassium hydroxide aqueous solution, hot water, and the like. For example, when a sodium hydroxide aqueous solution is used as the regenerating solution, the concentration of sodium hydroxide in the regenerating solution is preferably 0.1 to 10% by mass. If it is 0.1% by mass or more, the anion exchanger can be sufficiently regenerated, and if it is 10% by mass or less, efficient regeneration is possible and it is economically advantageous.

  As the oxidizing agent, one that can oxidatively decompose the organic fluorine compound contained in the regenerated waste liquid in the supercritical water oxidation reaction can be selected, and examples thereof include hydrogen peroxide, air, oxygen, and the like. The addition amount of the oxidizing agent can be determined in consideration of the organic fluorine compound concentration and the dissolved oxygen concentration in the recycled waste liquid. For example, the oxidant concentration in the regenerated waste liquid is preferably 1 to 2 times the amount of oxidant necessary for the oxidative decomposition of the organic fluorine compound in the regenerated waste liquid to carbon dioxide, water, and hydrofluoric acid. 1 to 1.5 times the amount is more preferable.

  The conditions for supercritical water oxidation treatment are temperature and pressure conditions for bringing water into a supercritical state. The temperature condition for the supercritical water oxidation treatment is 374 ° C. or higher, preferably 400 to 650 ° C. Moreover, the pressure conditions of supercritical water oxidation treatment are 22 MPa or more, and preferably 22 to 40 MPa.

  The residence time of the regenerated waste liquid in the reactor 120 can be determined in consideration of the concentration of the organic fluorine compound in the regenerated waste liquid, and is preferably determined in the range of 1 second to 60 minutes, for example. This is because, within the above range, the organic fluorine compound can be sufficiently oxidatively decomposed.

As described above, since the wastewater treatment system of the present embodiment has an electrodialysis device that is a pretreatment device, TAAH in the photoresist development wastewater is removed by the electrodialysis device, and TAAH / organic fluorine compound (mass ratio) is obtained. Reduced pretreatment water can be treated in an anion exchange column. As a result, the organic fluorine compound remaining in the pretreatment water can be removed satisfactorily. In the photoresist development waste water, TAAH dissociates into TAA ions and OH ^−, and the OH ⁻ concentration is high. For this reason, when the liquid is passed through the anion exchange tower without removing TAAH in the photoresist developing wastewater, the OH ⁻ dissociated in the photoresist developing wastewater is adsorbed to the anion exchanger and becomes an anion exchanger of organic fluorine compound ions. Is inhibited. Adsorption inhibition of an organic fluorine compound ion on an anion exchanger becomes more remarkable as TAAH / organic fluorine compound (mass ratio) is larger. Therefore, by removing TAA ions and OH ⁻ to reduce TAAH / organofluorine compound (mass ratio) at the front stage of the anion exchange tower, and reducing adsorption inhibition of the organofluorine compound ion on the anion exchanger, The organic fluorine compound in the photoresist developing waste water can be efficiently removed by the exchange tower.

  The wastewater treatment system of the present embodiment has means for flowing the regenerated liquid to the anion exchange tower, so that the anion exchanger can be regenerated and the wastewater purification process can be repeated. In addition, since the wastewater treatment system of the present embodiment has a decomposition device, it can be rendered harmless by decomposing the organic fluorine compound in the recycled waste liquid. Furthermore, since the organic fluorine compound can be detoxified with lower energy than incineration of the regenerated waste liquid by using a supercritical water oxidation apparatus as the decomposition apparatus, it is possible to treat the photoresist developing wastewater at a low running cost.

(Second embodiment)
A second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic diagram of a wastewater treatment system 200 according to the second embodiment. As shown in FIG. 3, the wastewater treatment system 200 includes a membrane separation device 220 that is a pretreatment device, and an anion exchange tower 30.

  The membrane separation device 220 is connected to a supply source (not shown) of the photoresist development waste water by the waste water supply line 21. A permeate outflow line 221 is connected to the permeate side of the membrane separation device 220, and the permeate outflow line 221 is connected to a permeate drain outlet (not shown). The concentrated water side of the membrane separator 220 is connected to the anion exchange tower 30 by connecting the pretreatment water outflow line 23. The pretreatment water outflow line 23 is provided with a valve 22, and a regenerated liquid supply line 41 is connected to a position between the anion exchange tower 30 and the valve 22. The regeneration liquid supply line 41 is connected to the regeneration liquid tank 40, and the regeneration liquid supply line 41 is provided with a regeneration pump 42. A first treated water outflow line 31 is connected to the anion exchange tower 30, and the first treated water outflow line 31 is connected to a first drain outlet (not shown). The first treated water outflow line 31 is provided with a valve 32, and the regenerated waste liquid inflow line 101 is connected to a position between the anion exchange tower 30 and the valve 32. The regeneration waste liquid inflow line 101 is provided with a valve 102, and the regeneration waste liquid inflow line 101 is connected to the decomposition apparatus 100. The decomposition apparatus 100 is connected to a second drain port (not shown) by a second treated water outflow line 103. The “means for flowing the water treated by the pretreatment device to the anion exchange tower” includes a pretreatment water outflow line 23 and a valve 22. The “means for flowing the regenerated liquid to the anion exchange tower” includes the pretreatment water outflow line 23, the regenerated liquid tank 40, the regenerated liquid supply line 41, and the regenerating pump 42.

  The membrane separation device 220 is a device that makes the photoresist development wastewater contact the separation membrane, removes components that do not permeate the separation membrane to the concentrated water side, and obtains permeated water that has permeated the separation membrane as pretreatment water. The separation performance of the separation membrane 20 in the membrane separation apparatus is such that it can be separated to the concentrated water side without passing through the TAAH and without passing through the organic fluorine compound. For example, it is preferable to select a separation membrane having a NaCl removal rate of 50 to 98%.

  The type of the separation membrane is not particularly limited, and examples include reverse osmosis membrane (RO membrane), nanofiltration membrane (NF membrane), microfiltration membrane (MF membrane), ultrafiltration membrane (UF membrane), etc. Among them, NF A membrane is preferred. The material of the separation membrane is not particularly limited, and examples thereof include a cellulose acetate asymmetric membrane and a synthetic polymer composite membrane which are natural polymers. Examples of the synthetic polymer composite membrane include those in which the skin layer material includes a polyamide-based material or an aromatic polyamide-based material. The form of the separation membrane is not particularly limited, and examples include a spiral type, a flat membrane type, and a hollow fiber type.

  A method for treating a photoresist developing wastewater using the wastewater treatment system 200 will be described with reference to FIGS. First, the valves 22 and 32 are opened, the valve 102 is closed, and the regeneration pump 42, the pressurizing pump 110, and the oxidant pump 114 are stopped. Next, the photoresist developing wastewater is caused to flow from the wastewater supply line 21 to the membrane separation device 220. The organic fluorine compound in the photoresist developing wastewater that has flowed into the membrane separation device 220 cannot pass through the separation membrane and is discharged to the concentrated water side. On the other hand, TAAH in the photoresist developing wastewater can be permeated through the separation membrane, and thus is contained in the concentrated water and the permeated water without being concentrated. The permeate flows out from the permeate outflow line 221. Thus, the photoresist developing wastewater becomes pretreated water in which the organic fluorine compound is concentrated and the TAAH / organic fluorine compound (mass ratio) is reduced, and the pretreated water flows out from the pretreated water outflow line 23 (pretreatment step). ).

  The pretreated water is allowed to flow from the pretreated water outflow line 23 to the anion exchange tower 30. The pretreated water that has flowed into the anion exchange tower 30 circulates through the anion exchanger filled in the anion exchange tower 30 and becomes the first treated water from which the organic fluorine compound has been removed. It flows to the first drain outlet via the line 31 (drainage purification process).

  After performing the above-described drainage purification process for an arbitrary period, the valve 102 is opened and the valves 22 and 32 are closed. Then, the regeneration pump 42, the pressurization pump 110, and the oxidant pump 114 are activated, and the regeneration liquid in the regeneration liquid tank 40 is caused to flow to the anion exchange tower 30 to regenerate the anion exchanger. The organic fluorine compound ions desorbed from the anion exchanger are taken into the regenerating solution. And the regeneration liquid (regeneration waste liquid) which took in the organic fluorine compound ion flows out into the first treated water outflow line 31 (regeneration process).

  The regenerated waste liquid flowing out to the first treated water outflow line 31 is supplied to the decomposition apparatus 100 via the regenerated waste liquid inflow line 101. The regenerated waste liquid is subjected to supercritical water oxidation treatment in the decomposition apparatus 100, and the organic fluorine compound ions in the regenerated waste liquid are rendered harmless (recycle liquid purification step).

  As described above, since the wastewater treatment system of the present embodiment has a membrane separation device which is a pretreatment device, the organic fluorine compound in the photoresist development wastewater is concentrated by the membrane separation device to obtain a TAAH / organic fluorine compound (mass ratio). ) Can be treated in an anion exchange column. As a result, the organic fluorine compound remaining in the pretreatment water can be removed satisfactorily. In addition, since the membrane separation device does not apply a DC voltage unlike the electrodialysis device, for example, the cost due to power consumption is small. For this reason, the processing of the photoresist development waste water can be performed at a lower running cost.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic diagram of a wastewater treatment system 300 according to the third embodiment. As shown in FIG. 4, the wastewater treatment system 300 includes a cation exchange tower 320 that is a pretreatment device and an anion exchange tower 30.

  The cation exchange tower 320 is connected to a supply source (not shown) of the photoresist development waste water by the waste water supply line 21. The cation exchange column 320 is connected to the anion exchange column 30 by the pretreatment water outflow line 23. The pretreatment water outflow line 23 is provided with a valve 22, and a regenerated liquid supply line 41 is connected to a position between the anion exchange tower 30 and the valve 22. The regeneration liquid supply line 41 is connected to the regeneration liquid tank 40, and the regeneration liquid supply line 41 is provided with a regeneration pump 42. A first treated water outflow line 31 is connected to the anion exchange tower 30, and the first treated water outflow line 31 is connected to a first drain outlet (not shown). The first treated water outflow line 31 is provided with a valve 32, and the regenerated waste liquid inflow line 101 is connected to a position between the anion exchange tower 30 and the valve 32. The regeneration waste liquid inflow line 101 is provided with a valve 102, and the regeneration waste liquid inflow line 101 is connected to the decomposition apparatus 100. The decomposition apparatus 100 is connected to a second drain port (not shown) by a second treated water outflow line 103. The “means for flowing the water treated by the pretreatment device to the anion exchange tower” includes a pretreatment water outflow line 23 and a valve 22. The “means for flowing the regenerated liquid to the anion exchange tower” includes the pretreatment water outflow line 23, the regenerated liquid tank 40, the regenerated liquid supply line 41, and the regenerating pump 42.

  The cation exchange column 320 is filled with an ion exchanger containing a cation exchanger. As the ion exchanger, for example, an ion exchange resin, an ion exchange fiber, a monolithic porous ion exchanger, or the like can be used. Of these, the most general-purpose ion exchange resin is preferably used.

  As the cation exchanger, those capable of adsorbing and removing cation components such as TAA ions contained in the photoresist development waste water can be selected, and examples thereof include strong acid cation exchangers and weak acid cation exchangers. Examples of the cation exchanger include amberlite (trade name, manufactured by Rohm and Haas) which is a cation exchange resin.

The ion form of the cation exchanger is not particularly limited, but the H form is preferred. This is because when the ion form is H-form, when TAA ions are adsorbed on the cation exchanger, H ⁺ is released, and OH ⁻ generated by dissociation of TAAH can be neutralized.

  The filling form of the ion exchanger of the cation exchange tower 320 can be determined in consideration of the water quality of the photoresist development waste water, etc., and the single bed form filled with the cation exchanger alone, the cation exchanger and the anion exchanger, The mixed bed form or the double bed form can be mentioned. Among these, from the viewpoint of efficiently removing TAA ions and the like in the photoresist development waste water, a single bed form of the cation exchanger is preferable. In addition, when setting it as the mixed bed form or multiple bed form of a cation exchanger and an anion exchanger, the cation exchanger in the ion exchanger with which the cation exchange column 320 is packed shall be 50 volume% or more and less than 100 volume%. It is preferable.

  The anion exchanger to be packed in the cation exchange column 320 can be determined in consideration of the water quality of the photoresist developing wastewater, and examples thereof include a strong basic anion exchanger and a weak basic anion exchanger. Examples of the anion exchanger include amberlite (trade name, manufactured by Rohm and Haas) which is an anion exchange resin.

A method for treating a photoresist developing wastewater using the wastewater treatment system 300 will be described with reference to FIGS. First, the valves 22 and 32 are opened, the valve 102 is closed, and the regeneration pump 42, the pressurizing pump 110, and the oxidant pump 114 are stopped. Next, the photoresist developing wastewater is caused to flow from the wastewater supply line 21 to the cation exchange tower 320. The photoresist development wastewater that has flowed into the cation exchange column 320 circulates while diffusing through the cation exchanger filled in the cation exchange column 320. During this time, in the photoresist development wastewater, cation components such as TAA ions are adsorbed on the cation exchanger. At this time, H ⁺ which is a counter ion of the cation exchange group is released into the photoresist development waste water. The released H ⁺ neutralizes OH ⁻ generated by dissociation of TAAH in the photoresist development waste water to generate water. As a result, the photoresist developing wastewater is free from cation components such as TAA ions and the OH ⁻ concentration is reduced. Then, the photoresist development wastewater is pretreated water from which TAAH is removed and TAAH / organic fluorine compound (mass ratio) is reduced, and the pretreated water flows out from the pretreated water outflow line 23 (pretreatment step).

The pretreated water is allowed to flow from the pretreated water outflow line 23 to the anion exchange tower 30. The pretreated water that has flowed into the anion exchange tower 30 flows while diffusing through the anion exchanger filled in the anion exchange tower 30. Since the pretreated water flowing into the anion exchange tower 30 has a low OH ⁻ concentration, the organic fluorine compound ions in the pretreated water are adsorbed on the anion exchanger without being inhibited. Thus, the pretreated water becomes the first treated water from which the organic fluorine compound has been removed, and flows to the first drain through the first treated water outflow line 31 (drainage purification step).

  After performing the above-described drainage purification process for an arbitrary period, the valve 102 is opened and the valves 22 and 32 are closed. Then, the regeneration pump 42, the pressurization pump 110, and the oxidant pump 114 are activated, and the regeneration liquid in the regeneration liquid tank 40 is caused to flow to the anion exchange tower 30 to regenerate the anion exchanger. The organic fluorine compound ions desorbed from the anion exchanger are taken into the regenerating solution. And the regeneration liquid (regeneration waste liquid) which took in the organic fluorine compound ion flows out into the first treated water outflow line 31 (regeneration process).

  The regenerated waste liquid flowing out to the first treated water outflow line 31 is supplied to the decomposition apparatus 100 via the regenerated waste liquid inflow line 101. The regenerated waste liquid is subjected to supercritical water oxidation treatment in the decomposition apparatus 100, and the organic fluorine compound ions in the regenerated waste liquid are rendered harmless (recycle liquid purification step).

The flow rate of the photoresist developing wastewater to the cation exchange tower 320 can be determined in consideration of the TAAH concentration and the type of ion exchanger packed in the cation exchange tower 320. For example, in this embodiment, SV = 1. It is preferable to determine in the range of -100L / L * h- ¹ . This is because, within the above range, TAAH can be adsorbed and removed as much as possible while preventing a reduction in the processing capacity of the wastewater treatment system 300.

As described above, since the wastewater treatment system of this embodiment has a cation exchange tower as a pretreatment device, the photoresist development wastewater is brought into contact with the cation exchanger to remove TAAH to a high degree to remove TAAH / An organic fluorine compound (mass ratio) can be reduced. In addition, the pretreated water treated in the cation exchange column is neutralized with OH ⁻ generated by dissociation from TAAH. As a result, the organic fluorine compound remaining in the pretreated water can be more highly removed in the anion exchange tower.

(Other embodiments)
The present invention is not limited to the above-described embodiment.
In the first to third embodiments, an electrodialyzer that removes TAAH from the photoresist development wastewater, a cation exchange tower, and a membrane separation device that concentrates the organic fluorine compound in the photoresist development wastewater are used as the pretreatment device. ing. However, the pretreatment apparatus in the present invention is not limited to an electrodialysis apparatus, a cation exchange tower, and a membrane separation apparatus, and can remove TAAH from photoresist development wastewater or concentrate an organic fluorine compound in photoresist development wastewater. Anything is acceptable.

  In the first to third embodiments, the wastewater treatment system has a means for flowing the regenerated liquid to the anion exchange tower and a decomposition device, but the wastewater treatment system of the present invention is not limited to this, and has a decomposition device. It does not have to be. For example, when the organic fluorine compound ion leaks (breaks over) an arbitrary concentration or more from the anion exchange column, the ion exchanger packed in the anion exchange column may be replaced with a new ion exchanger. However, considering the environmental impact of disposing of the broken-out ion exchanger, the ion exchanger packed in the anion exchange column is regenerated and the regenerated waste liquid generated is made harmless. It is preferable to have a flow means and a decomposition device.

  In the first to third embodiments, an oxidant supply line, an oxidant pump, and an oxidant supply source are provided in the supercritical water oxidation apparatus exemplified as the decomposition apparatus. However, the present invention is not limited to this. If the PFOS concentration in the regeneration waste liquid is low or the dissolved oxygen concentration in the regeneration waste liquid is high, the dissolved oxygen in the regeneration waste liquid can cover the oxidative decomposition of the organic fluorine compound. The oxidant supply line, the oxidant pump, and the oxidant supply source may not be provided. In addition, the reactor of the supercritical water oxidation apparatus may be a reactor that is not provided with a heater or the like, for example, when the concentrated liquid generates sufficient heat due to the decomposition reaction.

  In the first to third embodiments, the regeneration waste liquid flowing out from the anion exchange tower is directly supplied to the decomposition apparatus, but the present invention is not limited to this, for example, a storage tank for temporarily storing the regeneration waste liquid After storing an arbitrary amount of regenerated waste liquid in the storage tank, the regenerated waste liquid may be supplied from the storage tank to the decomposition device to render the organic fluorine compound in the regenerated waste liquid harmless.

  In the first to third embodiments, the obtained pretreated water is supplied to the decomposition apparatus as it is, but the present invention is not limited to this, and after the pretreated water is diluted or concentrated as necessary, the decomposition is performed. You may supply to an apparatus.

  In the first embodiment, a desalted water circulation line is provided to circulate the photoresist developing wastewater in the desalting chamber of the electrodialyzer, and the pretreated water is used as the pretreated water without circulating the photoresist developing wastewater. Good. In the second embodiment, the concentrated water of the membrane separator is not circulated, but the concentrated water may be circulated through the membrane separator to obtain pretreated water. In the third embodiment, the photoresist development wastewater is not circulated through the cation exchange tower, but the photoresist development wastewater may be circulated through the cation exchange tower as pretreatment water.

  In the third embodiment, means for regenerating the ion exchanger of the cation exchange column, that is, means for passing the regenerated solution through the cation exchange column may be provided.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, it is not limited to an Example.
(Measuring method)
<Measurement of PFOS concentration>
The PFOS concentration was measured using LC / MS / MS (liquid chromatograph / mass spectrometer) after solid phase extraction as required according to ISO / TC 147 / SC2 (2007-07-13). did.

<Measurement of TMAH concentration>
The TMAH concentration was measured by capillary electrophoresis.

Example 1
As the electrodialyzer, an electrodialyzer provided with a cation exchange membrane (trade name: Aciplex, manufactured by Asahi Kasei Co., Ltd.) and an anion exchange membrane (trade name: Aciplex, manufactured by Asahi Kasei Co., Ltd.) was used. As the anion exchange tower, a column having a diameter of 20 mm and 200 mL of an OH type anion exchange resin (recycled product of IRA 402BL, manufactured by Rohm and Haas) in a single bed form was used.
The photoresist development waste water was circulated through the desalting chamber of the electrodialyzer to obtain pretreated water, and the obtained pretreated water was passed through an anion exchange tower to obtain treated water. TMAH concentration and PFOS concentration were measured for pretreated water, concentrated water of electrodialyzer, and treated water. The measurement results are shown in Table 1. In addition, the process conditions in a present Example are as follows.

<Processing conditions>
Photoresist development wastewater: PFOS concentration; 100 μg / L, TMAH; 1700 mg / L
-Applied voltage of electrodialyzer: 12V constant voltage-Flow rate of photoresist development waste water to electrodialyzer; 60 L / h
-Flow rate of pretreated water through anion exchange tower: SV = 20 L / L · h ⁻¹

(Example 2)
As the cation exchange tower, a column having a diameter of 20 mm and 200 mL of an H-type cation exchange resin (recycled product of IR124, manufactured by Rohm and Haas) in a single bed form was used. The same anion exchange tower as in Example 1 was used.
A photoresist development wastewater was passed through the cation exchange tower to obtain pretreated water, and the obtained pretreated water was passed through the anion exchange tower to obtain treated water. TMAH concentration and PFOS concentration were measured for pretreated water and treated water. The measurement results are shown in Table 1. In addition, the process conditions in a present Example are as follows.

<Processing conditions>
Photoresist development wastewater: PFOS concentration; 100 μg / L, TMAH; 1700 mg / L
-Flow rate of photoresist development wastewater to cation exchange tower: SV = 20 L / L · h ⁻¹
-Flow rate of pretreated water through anion exchange tower: SV = 20 L / L · h ⁻¹

(Comparative Example 1)
The photoresist development waste water was passed through an anion exchange tower without pretreatment (SV = 20 L / L · h ⁻¹ ) to obtain treated water. About the obtained treated water, the TMAH density | concentration and PFOS density | concentration were measured. The measurement results are shown in Table 1. The anion exchange tower used in this comparative example is the same as in Example 1.

  In Table 1, TMAH / PFOS (mass ratio) of the photoresist development waste water and TMAH / PFOS (mass ratio) of the pretreatment water are described as “T / F ratio”. The T / F ratio of the photoresist development waste water used in Examples 1 and 2 and Comparative Example 1 was 17000/1.

  As shown in Table 1, in Example 1 in which the T / F ratio was reduced to 4000/1 in the pretreatment, treated water having a PFOS concentration of less than 0.005 μg / L was obtained. In addition, in Example 2 in which the T / F ratio was reduced to less than 20/1 in the pretreatment, treated water having a PFOS concentration of less than 0.005 μg / L was obtained. On the other hand, the PFOS concentration of the treated water of Comparative Example 1 in which the photoresist development wastewater having a T / F ratio of 17000/1 was treated with an anion exchange tower without a pretreatment had a PFOS concentration of 0.018 μg / L. From these results, it was found that the pretreatment for reducing the TAAH / organic fluorine compound (mass ratio) in the photoresist developing wastewater can be improved, and then the removal efficiency of the organic fluorine compound can be improved by passing the solution through an anion exchange tower. It was.

It is a schematic diagram which shows the waste water treatment system concerning 1st embodiment of this invention. It is a schematic diagram which shows the supercritical water oxidation apparatus which is an example of the decomposition | disassembly apparatus used for the waste water treatment system of this invention. It is a schematic diagram which shows the waste water treatment system concerning 2nd embodiment of this invention. It is a schematic diagram which shows the waste water treatment system concerning 3rd embodiment of this invention.

Explanation of symbols

10, 200, 300 Wastewater treatment system 20 Electrodialysis apparatus 22 Valve 23 Pretreatment water outflow line 30 Anion exchange tower 40 Regeneration liquid tank 41 Regeneration liquid supply line 42 Regeneration pump 100 Decomposition apparatus 220 Membrane separation apparatus 320 Cation exchange tower

Claims (6)

  Pretreatment device for reducing the content ratio expressed by tetraalkylammonium hydroxide / organic fluorine compound (mass ratio) in photoresist development wastewater containing organic fluorine compound and tetraalkylammonium hydroxide, and ion exchange including anion exchanger A wastewater treatment system for photoresist development wastewater, comprising: an anion exchange tower filled with a body; and means for flowing water treated by the pretreatment apparatus to the anion exchange tower.   The waste water treatment system for photoresist development waste water according to claim 1, wherein the pretreatment device is an electrodialysis device.   The waste water treatment system for photoresist development waste water according to claim 1, wherein the pretreatment device is a membrane separation device.   The waste water treatment system for photoresist development waste water according to claim 1, wherein the pretreatment device is a cation exchange tower filled with an ion exchanger containing a cation exchanger.   The drainage of the photoresist developing wastewater according to any one of claims 1 to 4, comprising means for flowing a regenerated solution through the anion exchange column and a decomposing device for decomposing the regenerated solution flowing through the anion exchange column. Processing system. The waste water treatment system for photoresist development waste water according to claim 5, wherein the decomposition device is a supercritical water oxidation device that brings the regenerated solution into a supercritical state.

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