JP2001017866A - Preparation of boron adsorbing resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent the elution of total org. carbon(TOC) from a boron-selective adsorbing resin by bringing the boron selective adsorbing resin into contact with a heated alkali metal hydroxide aq. soln. SOLUTION: A boron-selective adsorbing resin is brought into contact with a heated alkali metal hydroxide aq. soln. At this time, as the boron selective adsorbing resin, one having a polyhydric alcohol group is used. As polyhydric alcohol, one having a glucamine structure is used. The temp. of the alkali metal hydroxide aq. soln. is set to 50 deg.C or higher. As the alkali metal hydroxide aq. soln., a sodium hydroxide aq. soln. is used. By this constitution, the elution of org. carbon from the boron-selective adsorbing resin can be effectively prevented by a simple treatment and the boron-selective adsorbing resin can be effectively used as a means for removing boron from ultrapure water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for preparing a boron selective adsorption resin. More specifically, the present invention relates to a method for preparing a boron selective adsorption resin that can effectively prevent the elution of organic carbon (TOC) from the boron selective adsorption resin.

[0002]

2. Description of the Related Art If boron is contained in ultrapure water used for cleaning a silicon substrate for semiconductors, the boron adheres to the surface of the substrate, thereby impairing the characteristics of a manufactured semiconductor device. For this reason, it is extremely important to remove boron from ultrapure water, and a method for removing boron using a reverse osmosis membrane, a method for removing boron using a boron selective adsorption resin, and the like have been studied. The borate ion selectively binds to a polyhydric alcohol having a plurality of hydroxyl groups, saccharides, cellulose and the like to form a borate complex. There is a method for quantifying boron using a complex formation reaction with borate ion using mannitol, which is a kind of saccharide, and it is also known that a polysaccharide polymer based on dextran gel adsorbs boron. As a boron selective adsorption resin into which a polyhydric alcohol has been introduced, for example, a copolymer of styrene and divinylbenzene having a glucamine structure bonded thereto is commercially available. When ultrapure water is treated using such a boron selective adsorption resin, organic carbon is eluted from the boron selective adsorption resin. Ultrapure water used for cleaning a silicon substrate for semiconductors has a boron concentration of 10 ng / liter or less and a specific resistance of 1
Water quality of 8 MΩ · cm or more is required. The boron concentration can be reduced by incorporating a boron selective adsorption resin for removing trace amounts of boron into the primary water purification device or subsystem, but the organic carbon is eluted at 1 μg / liter or more and the specific resistance of ultrapure water is reduced. descend. Since the organic carbon eluted from the boron selective adsorption resin incorporated in the primary water purification device or the subsystem is not removed by the subsequent subsystem, there is a problem that the specific resistance of the terminal ultrapure water is reduced. JP-A-8-238478 discloses a glucamine exchange group, which is a weakly basic exchange group, as a method for reducing the amount of TOC eluted from a boron-selective ion exchange resin used by being incorporated in an ultrapure water production apparatus. A method has been proposed in which the compound is adjusted to a free base form and the strongly basic exchange group is adjusted to a salt form and used. However, in this method, it is necessary to bring the boron selective adsorption resin into contact with an aqueous solution of sodium hydroxide and then with an aqueous solution of sodium hydrogen carbonate, and the treatment is complicated because the adjustment of the boron selective adsorption resin is performed in two stages. In addition, there is a problem that the amount of waste liquid generated increases. For this reason, an adjustment method capable of reducing the amount of organic carbon eluted from the boron selective adsorption resin by a simpler treatment has been required.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preparing a boron selective adsorption resin which can effectively prevent the elution of organic carbon (TOC) from the boron selective adsorption resin. It was done.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a boron selective adsorption resin is brought into contact with a heated alkali metal hydroxide aqueous solution to obtain a boron selective adsorption resin. It has been found that elution of organic carbon from the selective adsorption resin can be effectively prevented, and the present invention has been completed based on this finding. That is, the present invention provides (1) a method for preparing a boron selective adsorption resin, which comprises contacting the boron selective adsorption resin with a heated aqueous alkali metal hydroxide solution. Further, as a preferred embodiment of the present invention, (2) the method for preparing a boron selective adsorption resin according to the above (1), wherein the boron selective adsorption resin has a polyhydric alcohol group, and (3) the polyhydric alcohol group has a glucamine structure (2) the method for adjusting a boron selective adsorption resin according to the item (2), (4) the method for adjusting a boron selective adsorption resin according to the item (1), wherein the temperature of the aqueous alkali metal hydroxide solution is 50 ° C. or more; And (5) the method for adjusting a boron selective adsorption resin according to the above (1), wherein the aqueous alkali metal hydroxide solution is an aqueous sodium hydroxide solution.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The method for preparing a boron selective adsorption resin according to the present invention comprises bringing the boron selective adsorption resin into contact with a heated aqueous alkali metal hydroxide solution. The method of the present invention can be suitably applied to a boron selective adsorption resin having a polyhydric alcohol group as the boron adsorption group. The boron selective adsorption resin having a polyhydric alcohol group, for example,
Those having a glucamine structure as a boron adsorbing group or those having a phenolic hydroxyl group (Japanese Patent Application No. 10-32)
No. 3826), but the method of the present invention can be particularly suitably applied to a boron selective adsorption resin having a boron adsorbing group having a glucamine structure. From the boron selective adsorption resin prepared by the method of the present invention, organic carbon is less eluted and ultrapure water having an organic carbon concentration of 1 μg / liter or less can be stably obtained, and the specific resistance is 18 MΩ · cm or more. And ultrapure water having a boron concentration of 10 ng / liter or less can be used as ultrapure water for semiconductor production and ultrapure water for fluorine product production. Examples of the aqueous alkali metal hydroxide solution used in the method of the present invention include a lithium hydroxide aqueous solution, a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a rubidium hydroxide aqueous solution, and a cesium hydroxide aqueous solution. Among these, an aqueous sodium hydroxide solution can be particularly preferably used. In the method of the present invention, there is no particular limitation on the method of bringing the boron selective adsorption resin into contact with the heated aqueous alkali metal hydroxide solution. However, following the regeneration of the boron selective adsorption resin, the method is brought into contact with the heated alkali metal hydroxide aqueous solution. Preferably. For example, a boron selective adsorption resin packed in a boron selective adsorption resin tower and adsorbing boron to reach a breakthrough point can be obtained by (1)
Water backwash, (2) settling, (3) regeneration with acid, (4) extrusion and
(5) After washing and completing the regeneration step, (6) heating the resin by passing hot water through, (7) contacting with the heated alkali metal hydroxide aqueous solution, (8) extrusion with hot water, (9) Washing with warm water and (10) cooling of the resin by passing water at normal temperature can adjust the boron selective adsorption resin. In these steps, it is preferable to use ultrapure water, an acid prepared using ultrapure water, and an alkali metal hydroxide aqueous solution prepared using ultrapure water. When using a new boron selective adsorption resin for the first time, (3) regeneration using acid,
The three steps of (4) extrusion and (5) washing can be omitted.

[0006] In the method of the present invention, prior to reproduction or adjustment.
It is possible to stand and perform (1) water backwash of the boron selective adsorption resin tower.
preferable. Water backwashing uses ultrapure water at room temperature,
It is preferable to carry out at 5 m / h for 15 to 60 minutes. Backwash
After finishing the process, stop the water flow and let the resin flow for about 5 minutes.
(2) is preferably calmed down. Perform water backwash and calm down
By doing so, the resin layer is expanded and loosened, and the resin is evenly distributed.
Distribute to prevent channeling and increase playback and adjustment efficiency
Can be (3) Especially restricted to acids used as regenerants
No, for example, hydrochloric acid, sulfuric acid, etc. can be used
You. The concentration of the acid is not particularly limited, but 3 to 10% by weight of water
It is preferably a solution. There are no special restrictions on the playback level
However, usually 150-250 g per liter of resin
It is preferable that the weight is 180 to 220 g.
Is more preferable. The flow rate of the regenerant aqueous solution is 2 to 2 times the resin capacity.
It is preferably 6 times, more preferably 3 to 5 times.
preferable. The flow rate of the regenerant aqueous solution is SV3 to 7h ^-1
And SV 4 to 6 h^-1It may be
Is more preferable. (4) Extrusion after regeneration is performed by using
5h^-1It is preferable to carry out for about 60 minutes. (5) Extrusion
Subsequent washing is performed using ultrapure water for SV10h.^-1About 60 minutes
It is preferable to perform it to the extent. In the method of the present invention,
Subsequent to the process, (6) heating the resin by passing hot water, (7) heating
Contact with warm alkali metal hydroxide aqueous solution, (8) warm water
And washing with hot water (9). These engineering
Of hot water and aqueous solution of alkali metal hydroxide
The temperature is preferably 50 ° C or higher, and 70 ° C or higher.
More preferably, there is. Hot water and water used for each process
The temperature of the aqueous solution of alkali metal hydroxide should be approximately equal.
preferable. (6) Heating resin by passing hot water
SV5h^-1By passing water for about 30 minutes.
Can be. Preheat the resin by contacting it with warm water
By heating, the heated alkali metal hydroxide aqueous solution
Adjustable from the beginning of the flow without reducing the temperature
Fruit can be obtained.

Hereinafter, a case where an aqueous solution of sodium hydroxide is used as an aqueous solution of an alkali metal hydroxide will be described. In the method of the present invention, (7) the concentration of the aqueous sodium hydroxide solution is not particularly limited, but is preferably 3 to 10% by weight. The regeneration level is not particularly limited, but is usually preferably from 150 to 250 g, more preferably from 180 to 220 g per liter of the resin. The flow rate of the aqueous sodium hydroxide solution is preferably 3 to 7 times, more preferably 4 to 6 times the resin capacity. The flow rate of the aqueous sodium hydroxide solution is from SV3 to
It is preferably 7h ^-1, and more preferably SV4~6h ^-1. (8) Extrusion after regeneration is preferably carried out using heated ultrapure water at an SV of about 5 h ^{-1 for} about 60 minutes. (9) Washing after extrusion is performed using heated ultrapure water.
It is preferable to carry out at about V5h ^{-1 for} about 240 minutes. After finishing the contact with the heated aqueous sodium hydroxide solution, the extrusion and the washing with warm water, it is preferable to finally pass (10) ultrapure water at room temperature to lower the temperature of the resin to room temperature. There are no particular restrictions on the conditions for passing ultrapure water at room temperature, but usually, the resin can be cooled to room temperature by passing water at an SV of about 10 h ^{-1 for} about 60 minutes. The above (1)
When ultrapure water is treated with the boron selective adsorption resin that has been regenerated and adjusted by the treatments of steps (10) to (10), the amount of organic carbon eluted into the treated water becomes 1 μg / liter or less, and the specific resistance is reduced. 18 MΩ · cm or more can be maintained, and the boron concentration of the treated water becomes 10 ng / liter or less. According to the method of the present invention, the resin is adjusted by a simple operation of heating the aqueous alkali metal hydroxide solution to be brought into contact with the boron selective adsorption resin, the specific resistance value is high, and the boron concentration is low, and the water quality is extremely pure. Water is produced and can be suitably used in a semiconductor production process, a fluorine product production process and the like.

[0008]

The present invention will be described in more detail with reference to the following examples.
The present invention is not limited to these examples.
It is not specified. In Examples and Comparative Examples,
The organic carbon concentration was measured using a TOC meter [Anatel].
Measured. Example 1 Boron selective adsorption resin newly used [Mitsubishi Chemical
Co., Ltd., Diaion CRBO2] was adjusted. Hou
The column packed with 0.2 liter
And adjusted by passing through in the order of. (1) Ultra-pure water at normal temperature, upward flow, LV = 10 m · h^-13
It was backwashed by passing water for 0 minutes, and (2) it was settled for 5 minutes. next,
(3) Ultrapure water at 80 ° C., downward flow, SV = 5h^-1In 30 minutes
(4) 2% by weight at 80 ° C
Sodium hydroxide aqueous solution, downward flow, SV = 5h^-1At 1
The solution was passed for 20 minutes to adjust the boron selective adsorption resin.
Next, (5) ultrapure water at 80 ° C. was flowed downward, SV = 5 h^-1
And extruded by passing water for 60 minutes.
Pure water, downward flow, SV = 5h^-1Wash with water for 240 minutes
After purification, (7) Ultra-pure water at room temperature, downward flow, SV = 10
h^-1Water for 60 minutes to cool the boron selective adsorption resin
Was. Subsequently, the organic carbon concentration is 0.5 to 1 μg / liter.
Of ultrapure water, downward flow, SV = 45h^-1Water through the column
The concentration of organic carbon in the treated water flowing out of the
Was. The organic carbon concentration of the treated water is 9.9 μg / hour after 1 hour.
Liter, 4.8 μg / liter after 2 hours, 2.
2 μg / liter, after 6 hours 1.6 μg / liter, 8
1.4 μg / l after 10 hours, 1.2 μg / l after 10 hours
Turtle, 1.2 μg / l after 12 hours, 14 hours
It was 1.0 μg / liter. Example 2 The boron selective adsorption resin prepared in Example 1 adsorbs boron.
When the breakthrough point is reached, the liquid is passed in the following order to regenerate and adjust.
Was adjusted. (1) Ultra-pure water at normal temperature, upward flow, LV = 10 m · h^-13
It was backwashed by passing water for 0 minutes, and (2) was settled for 5 minutes. next,
(3) 5% by weight hydrochloric acid at room temperature, downward flow, SV = 5h ^-1At 5
Pass the solution for 0 minutes to desorb boron, and (4) ultrapure water at room temperature
Downflow, SV = 5h^-1Water for 60 minutes to extrude,
(5) Ultra-pure water at room temperature, downward flow, SV = 10h^-1In 60 minutes
Water was passed for washing. Next, (6) ultrapure water at 80 ° C.
Downflow, SV = 5h^-1Water for 30 minutes to heat the resin
(7) 2% by weight aqueous sodium hydroxide solution at 80 ° C
With downward flow, SV = 5h^-1Pass through for 120 minutes with boron
Adjustment of the selective adsorption resin was performed. Further, (8) exceeding 80 ° C.
Pure water, downward flow, SV = 5h ^-1Extrude by passing water for 60 minutes
(9) Ultrapure water at 80 ° C. was flowed downward, SV = 5 h ^-1
After washing with water for 240 minutes in (10) Ultra pure at room temperature
Water is flowed downward, SV = 10h^-1Water for 60 minutes
The elementally selective adsorption resin was cooled. Next, the organic carbon concentration
0.5 to 1 μg / liter of ultrapure water, downward flow, SV =
45h^-1Of treated water flowing through the column and flowing out of the column
The carbon concentration was measured over time. Organic carbon concentration of treated water
Is 10.1 μg / liter after 1 hour and 4.6 μ after 2 hours
g / liter, after 4 hours 2.1 μg / liter, 6 hours
1.6 μg / liter after 8 hours, 1.3 μg / lit after 8 hours
1.0 μg / liter after 10 hours, 1.0 after 12 hours
μg / liter and 0.9 μg / liter after 14 hours.
Was. In addition, a boron-containing test water is
Flow, SV = 45h^-1To conduct a boron removal test
Was. The test water was prepared by adding boric acid to ultrapure water and
5 μg / liter and 10 μg / liter
Using. Pass test water with a boron concentration of 5 μg / liter
When the concentration of boron in the treated water flowing out of the column is 10
ng / liter or less. Boron concentration 10μg / liter
Even when the test water of the turtle is passed, the boron concentration of the treated water
Was 10 ng / liter or less. Comparative Example 1 A boron selective adsorption resin was mixed with an aqueous solution of sodium hydroxide at room temperature.
Same as Example 2 except that it was adjusted by contact
The operation was repeated. Selective boron adsorption prepared in Example 2
The resin is subsequently used for ultrapure water treatment,
When the breakthrough point is reached by adsorption, liquid is passed in the following order to regenerate
And made adjustments. (1) Ultra-pure water at normal temperature, upward flow, LV = 10 m · h^-13
It was backwashed by passing water for 0 minutes, and (2) it was settled for 5 minutes. next,
(3) 5% by weight hydrochloric acid at room temperature, downward flow, SV = 5h ^-1At 5
Pass the solution for 0 minutes to desorb boron, and (4) ultrapure water at room temperature
Downflow, SV = 5h^-1Water for 60 minutes to extrude,
(5) Ultra-pure water at room temperature, downward flow, SV = 10h^-1In 60 minutes
Water was passed for washing. Next, (6) ultra-pure water at room temperature
Countercurrent, SV = 5h^-1Water for 30 minutes at (7) room temperature
Of a 2% by weight aqueous sodium hydroxide solution in a downward flow, SV =
5h^-1Of boron selective adsorption resin by passing the solution for 120 minutes
Was done. (8) Ultra-pure water at room temperature is supplied
= 5h^-1And extruded by passing water for 60 minutes.
Pure water, downward flow, SV = 5h^-1Wash with water for 240 minutes
After purification, (10) Ultra-pure water at room temperature, downward flow, SV = 1
0h^-1For 60 minutes. Next, the organic carbon concentration
0.5 to 1 μg / liter of ultrapure water, downward flow, SV =
45h^-1Of treated water flowing through the column and flowing out of the column
The carbon concentration was measured over time. Organic carbon concentration of treated water
Is 260 μg / liter after 1 hour and 75 μg after 2 hours
/ Liter, 41 μg / liter after 4 hours, 3 after 6 hours
5 μg / liter, after 8 hours 29 μg / liter, 10
27 μg / liter after 12 hours, 25 μg / liter after 12 hours
Torr, 25 μg / liter after 14 hours. Example
Table 1 shows the concentration of organic carbon in the treated water of Examples 1 and 2 and Comparative Example 1.
Table 2 shows the boron concentrations of the test water and the treated water in Example 2.
Show.

[0009]

[Table 1]

[0010]

[Table 2]

As can be seen from Table 1, the boron selective adsorption resin of Example 1 which is adjusted by the method of the present invention and newly used is also the boron selective adsorption resin of Example 2 which is adjusted by the method of the present invention after regeneration. Also, 14 hours after the start of water passage, the concentration of organic carbon in the treated water has dropped to 1 μg / liter. On the other hand, in Comparative Example 2 in which the boron selective adsorption resin was adjusted by bringing it into contact with an aqueous solution of sodium hydroxide at normal temperature, 25 μg / L of organic carbon was eluted even 14 hours after the start of water passage. Further, as shown in Table 2, the boron selective adsorption resin of Example 2 prepared by the method of the present invention has a sufficient boron adsorption removal ability.

[0012]

According to the method for preparing a boron selective adsorption resin of the present invention, the elution of organic carbon from the resin can be effectively performed by a simple treatment of heating the aqueous alkali metal hydroxide solution and bringing it into contact with the resin. And the boron selective adsorption resin can be effectively used as a means for removing boron from ultrapure water.

Claims (1)

[Claims] 1. A method for preparing a boron selective adsorption resin, comprising contacting the boron selective adsorption resin with a heated aqueous alkali metal hydroxide solution.