How to prepare anion exchange resin

Abstract

To provide an adjustment method of a weakly basic anion exchange resin which can reduce a washing period after performing, a regeneration process of a FB Type weakly basic anion exchange resin.SOLUTION: An adjustment method of an anion exchange resin comprises: a regeneration process for bringing an alkali metal hydroxide aqueous solution into contact with an anion exchange resin, for converting the anion exchange resin into a FB type; and a washing process for bringing washing water into contact with the FB type anion exchange resin converted into the FB type, for washing the FB type anion exchange resin. The anion exchange resin is a weakly basic anion exchange resin, and a normality of the alkali metal hydroxide aqueous solution is 0.025 to 0.50 N, in the adjustment method of the anion exchange resin.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for preparing an anion exchange resin for converting a weakly basic anion exchange resin into an FB (free base) form, and more particularly to a method for preparing an anion exchange resin for regenerating or pretreating an anion exchange resin used in a method for purifying water to be treated that contains ionic impurities. [Background technology]

[0002] Ultrapure water with an anion impurity concentration of 1ng / L or less is required for the silicon washing process in semiconductor manufacturing. The most common method for reducing the concentration of anion impurities in water, mainly mineral acids such as chloride ions, sulfate ions, and nitrate ions, is to use a weakly basic anion exchange resin.

[0003] For example, Patent Document 1 discloses an example of ultrapure water production using a weakly acidic cation exchange resin, a strongly acidic cation exchange resin, a weakly basic anion exchange resin, and a strongly basic anion exchange resin as primary treatment for ultrapure water production.

[0004] When the removal of anionic impurities from the water being treated is continued using a weakly basic anion exchange resin, the basic ion exchange groups in the weakly basic anion exchange resin are used up by binding with the anionic impurities, and the amount of ion exchange groups available for adsorbing anionic impurities decreases.

[0005] When all the ion exchange groups in the weakly basic anion exchange resin have been used up, the resin will lose its ability to remove anionic impurities. Therefore, before this happens, it is necessary to temporarily halt the treatment of the water to be treated and bring the weakly basic anion exchange resin into contact with an aqueous solution of an alkali metal hydroxide, such as an aqueous solution of sodium hydroxide, to regenerate it into the FB form and restore the adsorption properties of the weakly basic anion exchange resin.

[0006] Furthermore, since alkali metal ions remain in the anion exchange resin after it has been regenerated into the FB type by contacting the weakly basic anion exchange resin with an aqueous alkali metal solution, it is necessary to wash the regenerated weakly basic anion exchange resin with ultrapure water or the like to remove the alkali metal ions from the weakly basic anion exchange resin and suppress the elution of the alkali metal ions.

[0007] For example, cited document 2 describes the playback method recommended by the manufacturer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Ion exchange resins: their technology and applications (practical edition) 223 pages [Patent Document 2] Lanxess Weak Acid Cation Exchange Resin MP62 Data Sheet DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0009] However, the method of Patent Document 2 has a problem in that it takes a long time to wash the basic anion exchange resin after it is regenerated with an aqueous sodium hydroxide solution. Furthermore, the fact that it takes a long time to wash the resin after regeneration leads to inefficiency in the entire process of purifying ultrapure water using a weakly basic anion exchange resin.

[0010] Therefore, the present invention provides a method for preparing a weakly basic anion exchange resin in FB (free base) form, which can reduce the washing time after the regeneration process of the weakly basic anion exchange resin in FB (free base) form. [Means for solving the problem]

[0011] In light of this technical background, the inventors conducted extensive research and discovered that the washing time after the regeneration step of a FB (free base) type weakly basic anion exchange resin can be shortened by setting the concentration of the aqueous alkali metal hydroxide solution brought into contact with the anion exchange resin within a specific range during the regeneration step, thereby completing the present invention.

[0012] That is, the present invention (1) is Anion exchange resin is packed in a container. Anion Exchange Resin Floor Add an aqueous solution of alkali metal hydroxide to Liquid passing speed SV8~160h -1 in and a regeneration step of converting the anion exchange resin to the FB form by contacting the anion exchange resin with a washing step of washing the FB type anion exchange resin by contacting the FB type anion exchange resin converted to the FB type with washing water; having The anion exchange resin is a weakly basic anion exchange resin, The aqueous alkali metal hydroxide solution Equivalents per liter However, 0.025 to 0.50 Equivalent / L That is, In the regeneration step, the relationship between the number of equivalents A per 1 L of the aqueous alkali hydroxide solution and the flow rate B of the aqueous alkali metal hydroxide solution is expressed by the following formula (1): A×B≦4.5 (1) (In the formula, A is the number of equivalents per 1 L of the alkali metal hydroxide aqueous solution (equivalents / L), and B is the flow rate SV (h -1 ) To satisfy the following: The present invention provides a method for preparing an anion exchange resin, comprising the steps of:

[0013] In addition, the present invention (2) provides an anion exchange resin packed container in which a bed of the anion exchange resin is packed, Equivalents per liter is 0.025~0.50 Equivalent / L The aqueous alkali metal hydroxide solution is subjected to SV8 to 160 h -1 The present invention provides a method for preparing an anion exchange resin according to the above aspect, characterized in that the regeneration step is carried out by passing a liquid through the anion exchange resin at a flow rate of 100 / min.

[0015] In addition, the present invention ( 3The anion exchange resin has a dimethylamino group as an ion exchange group. Or (2) The present invention provides a method for preparing an anion exchange resin.

[0016] In addition, the present invention ( 4 ) is characterized in that the substrate of the anion exchange resin is a styrene-divinylbenzene copolymer (1) to ( 3 The present invention provides a method for preparing an anion exchange resin of the above formula (I).

[0017] In addition, the present invention ( 5 ) is characterized in that in the regeneration step, the temperature of the aqueous alkali metal hydroxide solution brought into contact with the anion exchange resin is 15 to 30° C. 4 The present invention provides a method for preparing an anion exchange resin of the above formula (I). Effect of the Invention

[0018] According to the present invention, a method for preparing a weakly basic anion exchange resin can be provided, which can reduce the washing time after carrying out a regeneration step of an FB (free base) type weakly basic anion exchange resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The method for preparing an anion exchange resin of the present invention includes a regeneration step of converting the anion exchange resin into an FB form by contacting the anion exchange resin with an aqueous alkali metal hydroxide solution; a washing step of washing the FB type anion exchange resin by contacting the FB type anion exchange resin converted to the FB type with washing water; having The anion exchange resin is a weakly basic anion exchange resin, The aqueous alkali metal hydroxide solution Equivalents per liter However, 0.025 to 0.50 Equivalent / L That is, The method for preparing an anion exchange resin is characterized by the following.

[0020] The method for preparing an anion exchange resin of the present invention includes a regeneration step and a washing step.

[0021] The regeneration step is a step in which the weakly basic anion exchange resin is converted to the FB form (free base form) by contacting the weakly basic anion exchange resin with an aqueous alkali metal hydroxide solution.

[0022] In the regeneration step, the anion exchange resin that is brought into contact with the aqueous alkali metal hydroxide solution is a weakly basic anion exchange resin. Since the free base form of the weakly basic anion exchange resin regenerated with the alkali metal hydroxide solution is the most stable state, the weakly basic anion exchange resin has superior regeneration efficiency with the alkali metal hydroxide solution, etc., compared to the strongly basic anion exchange resin.

[0023] The anion exchange group of the weakly basic anion exchange resin is not particularly limited, and examples thereof include a primary amino group, a secondary amino group, a tertiary amino group, pyrroles, pyridines, etc., and specifically includes a dimethylamino group, an amino group, a monomethylamino group, a pyridine group, etc. Among these, the dimethylamino group is preferred as the anion exchange group.

[0024] The weakly basic anion exchange resin is not particularly limited as long as it is an ion exchange resin in which an anion exchange group is introduced into a resin base, and may be in various forms such as powder, beads, or a membrane, and may be either a gel-type ion exchange resin or a porous-type ion exchange resin.

[0025] Gel-type ion exchange resins and porous-type ion exchange resins are classified based on the microstructure of ion exchange resins. Among these, gel-type ion exchange resins are ion exchange resins based on styrene and divinylbenzene polymerized without a solvent, which have a non-uniformly crosslinked gel-like structure and are the most classical ion exchange resins. In addition, porous-type ion exchange resins refer to ion exchange resins based on resins in which macropores with pore sizes of about 20 nm to 100 nm are formed by using a solvent during polymerization, and include those called MP type (macroporous type) and MR type (macroreticular type). Porous-type ion exchange resins have macropores that are not continuous and lack uniformity, so they have a lower ion exchange capacity than gel-type resins, but they have high physical strength and excellent resistance to osmotic pressure and mechanical pressure.

[0026] The substrate to which the anion exchange group is bonded is preferably one or more selected from, for example, styrene-based compounds such as cross-linked polystyrene and styrene-divinylbenzene copolymer, condensates of phenols and aldehydes, cross-linked polyacrylic acid, etc., and more preferably cross-linked polystyrene or styrene-divinylbenzene copolymer.

[0027] As the weakly basic anion exchange resin, an MR type or MP type weakly basic anion exchange resin having a weakly basic anion exchange group and based on a styrene-divinylbenzene copolymer is preferable.

[0028] The shape of the weakly basic anion exchange resin is not particularly limited, but when it has a granular shape, the average particle size is preferably 0.2 to 1.0 mm, more preferably 0.4 to 0.8 mm.

[0029] The weakly basic anion exchange resin may be a commercially available product. Examples of such a weakly basic anion exchange resin include AMBERLITE IRA96SB and AMBERLITE HPR9700 manufactured by DuPont, DIAION WA30 manufactured by Mitsubishi Chemical Corporation, and Lewatit MP62 manufactured by Lanxess.

[0030] In the regeneration step, the weakly basic anion exchange resin to be contacted with the aqueous alkali metal hydroxide solution may be a weakly basic anion exchange resin that has been used in the purification of the water to be treated and thus needs to be regenerated, i.e., a weakly basic anion exchange resin in which anionic impurities are adsorbed to the anion exchange group. In addition, when the weakly basic anion exchange resin is pretreated by contacting with an aqueous alkali metal hydroxide solution before being used in the purification of the water to be treated, and converted into the FB form, the weakly basic anion exchange resin to be contacted with the aqueous alkali metal hydroxide solution in the regeneration step may be a weakly basic anion exchange resin that has never been used in the purification of the water to be treated.

[0031] In the regeneration step, the aqueous alkali metal hydroxide solution brought into contact with the weakly basic anion exchange resin is an aqueous solution of an alkali metal hydroxide such as sodium hydroxide, potassium hydroxide, or lithium hydroxide.

[0032] Alkali metal hydroxide solution Equivalents per liter is 0.025 to 0.50 Equivalent / L , preferably 0.025 to 0.20 Equivalent / L , and particularly preferably 0.025 to 0.10 Equivalent / L The alkali metal hydroxide solution Equivalents per liter By setting the content of the aqueous alkali metal hydroxide solution in the above range, the washing time of the washing step can be shortened. Equivalents per liter However, if the amount is less than the above range, the conversion of the weakly basic anion exchange resin to the FB type becomes insufficient, and if the amount is more than the above range, the washing time in the washing step becomes long.

[0033] In the regeneration step, the temperature of the aqueous alkali metal hydroxide solution brought into contact with the weakly basic anion exchange resin is preferably 15 to 60° C., particularly preferably 20 to 50° C. When the temperature of the aqueous alkali metal hydroxide solution brought into contact with the weakly basic anion exchange resin is within the above range, the regeneration of the weakly basic anion exchange resin can be efficiently performed. On the other hand, if the temperature of the aqueous alkali metal hydroxide solution brought into contact with the weakly basic anion exchange resin is less than the above range, the conversion of the weakly basic anion exchange resin to the FB form is likely to be insufficient, and if it exceeds the above range, the functional group of the weakly basic anion exchange resin may be deteriorated, causing a decrease in the exchange capacity.

[0034] In the regeneration step, the method of contacting the weakly basic anion exchange resin with the aqueous alkali metal hydroxide solution includes filling an anion exchange resin-filled container with the weakly basic anion exchange resin to form a resin bed of the anion exchange resin in the anion exchange resin-filled container, then passing an aqueous alkali metal hydroxide solution through the anion exchange resin-filled container filled with the anion exchange resin bed to bring the aqueous alkali metal hydroxide solution into contact with the anion exchange resin in the anion exchange resin-filled container, and discharging the aqueous alkali metal hydroxide solution after contact with the anion exchange resin from the anion exchange resin-filled container.

[0035] Other methods for contacting the aqueous alkali metal hydroxide solution with the weakly basic anion exchange resin in the regeneration step include a batch method such as immersion, or a column method in which a liquid is passed continuously.

[0036] When the aqueous alkali metal hydroxide solution is brought into contact with the weakly basic anion exchange resin by passing the aqueous alkali metal hydroxide solution through a weakly basic anion exchange resin bed packed in an anion exchange resin packed container, the passing speed SV of the aqueous alkali metal hydroxide solution through the anion exchange resin bed is preferably 8 to 160 h -1 It is.

[0037] And, the alkali metal hydroxide aqueous solution Equivalents per liter is 0.025~0.50 Equivalent / L , more preferably 0.025 to 0.20 Equivalent / L , and particularly preferably 0.025 to 0.10 Equivalent / L and the flow rate SV of the alkali metal hydroxide aqueous solution through the anion exchange resin bed is 8 to 160 h -1 is preferable in that the time required for the regeneration step can be shortened.

[0038] When the aqueous alkali metal hydroxide solution is brought into contact with the weakly basic anion exchange resin by passing the aqueous alkali metal hydroxide solution through a weakly basic anion exchange resin bed packed in an anion exchange resin packed container, Equivalents per liter The relationship between A and the flow rate B of the alkali metal hydroxide aqueous solution through the anion exchange resin bed is expressed by the following formula (1): A×B≦4.5 (1) (Wherein, A is an aqueous solution of an alkali hydroxide Equivalents per liter ( Equivalent / L ) and B is the flow rate SV (h -1 ) It is preferable that the above-mentioned condition is satisfied. Equivalents per liter The time for the regeneration step can be shortened by satisfying the relationship between A and the flow rate B of the aqueous alkali metal hydroxide solution through the anion exchange resin bed as given in the above general formula (1). A more preferred range is 0.01≦A×B≦4.5, and an especially preferred range is 0.1≦A×B≦4.0. When the value of A×B is less than 0.01, the total amount of alkali metal hydroxide required for regeneration and the amount of the aqueous alkali metal hydroxide solution passing through the anion exchange resin bed become too large. Equivalents per liter For A in the range of 0.025 to 0.20, the SV of the water flow is 1 or less, so the regeneration process takes a very long time. On the other hand, when the value of A x B exceeds 4.5, the SV becomes high, which means the water flow rate becomes fast, and regeneration failure is likely to occur due to a decrease in the contact time between the alkali metal hydroxide aqueous solution and the ion exchange resin, which is necessary for regeneration.

[0039] Then, by carrying out the regeneration process, anionic impurities are desorbed from the anion exchange groups of the anion exchange resin, the anion impurities are removed from the anion exchange resin, and the anion exchange groups of the anion exchange resin are converted to FB type, so that the anion exchange resin is converted to FB type anion exchange resin, and the anion exchange resin is regenerated.

[0040] The washing process is a process for washing the FB type anion exchange resin by contacting the weakly basic anion exchange resin (hereinafter also referred to as FB type anion exchange resin) that has been converted to the FB type by the regeneration process with washing water. Since alkali metal ions remain inside and on the surface of the FB type anion exchange resin and in the gaps between the particles of the anion exchange resin after the regeneration process, it is necessary to remove the alkali metal ions remaining in the FB type anion exchange resin before purifying the water to be treated using the FB type anion exchange resin. Therefore, the washing process is performed to remove the alkali metal ions remaining inside and on the surface of the FB type anion exchange resin and in the gaps between the particles of the anion exchange resin.

[0041] In the washing step, the washing water to be brought into contact with the FB type anion exchange resin preferably has a lower impurity content. Examples of the washing water include ultrapure water.

[0042] In the washing step, the temperature of the washing water brought into contact with the FB type anion exchange resin is preferably 15 to 60°C, particularly preferably 20 to 50°C. When the temperature of the washing water brought into contact with the FB type anion exchange resin is within the above range, the aqueous alkali metal hydroxide solution can be easily discharged appropriately. On the other hand, if the temperature of the washing water brought into contact with the FB type anion exchange resin is below the above range, the diffusion of the aqueous alkali metal hydroxide solution becomes poor, which tends to result in poor washing, and if it exceeds the above range, this may lead to deterioration of the functional group of the weakly basic anion exchange resin, resulting in a decrease in the exchange capacity.

[0043] In the washing step, the method of bringing the washing water into contact with the FB type anion exchange resin includes passing the washing water through an anion exchange resin-packed container filled with FB type anion exchange resin, bringing the washing water into contact with the FB type anion exchange resin in the anion exchange resin-packed container, and discharging the washing water after contacting with the FB type anion exchange resin from the anion exchange resin-packed container.

[0044] Other methods for contacting the FB type anion exchange resin with the wash water in the washing step include a batch method such as immersion, or a column method in which a liquid is continuously passed through the resin.

[0045] When the cleaning water is passed through the FB type anion exchange resin bed packed in the anion exchange resin packed container to contact the FB type anion exchange resin, the passing speed SV of the cleaning water through the FB type anion exchange resin bed is preferably 40 to 400 h -1 It is.

[0046] Then, by carrying out a washing step, the anion exchange resin is adjusted to an FB type anion exchange resin to be used for purifying the water to be treated.

[0047] After carrying out the method for preparing an anion exchange resin of the present invention, the FB type anion exchange resin that has been subjected to the regeneration step and the washing step is used to carry out a purification step in which the water to be treated is purified to obtain treated water.

[0048] In the purification step, purification treatment conditions such as the temperature of the water to be treated and the rate of passing the water through the FB type anion exchange resin are appropriately selected.

[0049] In the purification step, anion impurities in the water to be treated are adsorbed to the anion exchange groups of the FB anion exchange resin, so that the amount of anion exchange groups capable of adsorbing anion impurities in the FB anion exchange resin decreases as purification is continued. Therefore, before all of the anion exchange groups capable of adsorbing anion impurities in the FB anion exchange resin are used for adsorption of anion impurities and the anion impurity removal performance is lost, the purification step is interrupted and the method for adjusting the anion exchange resin of the present invention is carried out again.

[0050] In the method for preparing an anion exchange resin of the present invention, the amount of alkali metal ions remaining in the FB-type anion exchange resin can be quickly reduced in the washing step after the regeneration step, and therefore the washing time can be shortened. For example, in the method for preparing an anion exchange resin of the present invention, in the washing step after the regeneration step, the time until the resistivity of the washing water after contacting with the anion exchange resin reaches 10 MΩ·cm is shortened. Also, for example, in the method for preparing an anion exchange resin of the present invention, in the washing step after the regeneration step, the resistivity of the washing water after contacting with the anion exchange resin one hour after the start of washing is higher than that in the conventional method for regenerating an anion exchange resin. EXAMPLES

[0051] The present invention will be described in more detail below by showing examples, but the present invention is not limited thereto.

[0052] Example 1 A column packed with weakly basic anion exchange resin (AMBERLITE IRA96SB, DuPont) with a resin volume of 500 mL (500 mL-R) was used. Equivalent / L The HCl aqueous solution is passed through the tube at a flow rate (liquid hourly space velocity) of 4 h -1 Pretreatment was performed by passing water through the solution for 50 minutes so that the solution became Next, 0.50 Equivalent / L The NaOH aqueous solution is passed through at a flow rate of SV of 8 hr. -1 Water was passed through the solution for 60 minutes so that the ionic form of the functional group was converted to the FB form. After this, the resin converted to FB type was subjected to ultrapure water at a liquid hourly space velocity (SV) of 50 h -1 The resistivity (MΩ cm) of the resulting treated water was measured. The results are shown in Table 1.

[0053] Example 2 0.50 Equivalent / L Instead of 0.20 NaOH solution, Equivalent / L The same procedure as in Example 1 was carried out, except that an aqueous NaOH solution of 100 g / l was used and the flow rate of the aqueous NaOH solution was set as shown in Table 1. The results are shown in Table 1.

[0054] Example 3 0.50 Equivalent / L Instead of NaOH solution, 0.10 Equivalent / L The same procedure as in Example 1 was carried out, except that an aqueous NaOH solution of 100 g / l was used and the flow rate of the aqueous NaOH solution was set as shown in Table 1. The results are shown in Table 1.

[0055] Example 4 0.50 Equivalent / L Instead of 0.025 NaOH solution, Equivalent / L The same procedure as in Example 1 was carried out, except that an aqueous NaOH solution of 100 g / l was used and the flow rate of the aqueous NaOH solution was set as shown in Table 1. The results are shown in Table 1.

[0056] Comparative Example 1 0.20 Equivalent / L Instead of the NaOH solution, 1.0 Equivalent / L The same procedure as in Example 1 was carried out, except that an aqueous NaOH solution of 100 g / l was used and the flow rate of the aqueous NaOH solution was set as shown in Table 1. The results are shown in Table 1.

[0057] [Table 1]

[0058] In Examples 1 to 4 and Comparative Example 1, the amount of NaOH passed through the regeneration process was Equivalents per liter Based on the flow rate and time, the regeneration was sufficient.

Claims

1. A regeneration process for converting an anion exchange resin into an FB form by contacting a bed of an anion exchange resin packed in an anion exchange resin packed container with an aqueous alkali metal hydroxide solution at a flow rate SV of 8 to 160 h -1 ; a washing step of washing the FB-form anion exchange resin by contacting the FB-form anion exchange resin with washing water; having The anion exchange resin is a weakly basic anion exchange resin, the number of equivalents per 1 L of the aqueous alkali metal hydroxide solution is 0.025 to 0.50 equivalents / L; In the regeneration step, the relationship between the number of equivalents A per 1 L of the aqueous alkali hydroxide solution and the flow rate B of the aqueous alkali metal hydroxide solution is expressed by the following formula (1): A × B≦4.5 (1) (In the formula, A is the number of equivalents per 1 L of the aqueous alkali metal hydroxide solution (equivalents / L), and B is the flow rate SV (h −1 ) of the aqueous alkali metal hydroxide solution.) To satisfy the following: A method for preparing an anion exchange resin comprising the steps of:

2. The aqueous alkali metal hydroxide solution having an equivalent number per 1 L of 0.025 to 0.50 equivalent / L is added to an anion exchange resin packed container in which a bed of the anion exchange resin is packed, and the aqueous alkali metal hydroxide solution is mixed with the anion exchange resin at a temperature of SV8 to 160 h. －１ 2. The method for preparing an anion exchange resin according to claim 1, wherein the regeneration step is carried out by passing the liquid through the anion exchange resin at a rate of 1:

3. 3. The method for preparing an anion exchange resin according to claim 1, wherein the anion exchange resin has a dimethylamino group as an ion exchange group.

4. 4. The method for preparing an anion exchange resin according to claim 1, wherein the substrate of the anion exchange resin is a styrene-divinylbenzene copolymer.

5. 5. The method for preparing an anion exchange resin according to claim 1, wherein the temperature of the aqueous alkali metal hydroxide solution contacted with the anion exchange resin in the regeneration step is 15 to 30°C.

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