JP3757474B2 - Ion exchange resin regeneration method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for regenerating an ion exchange resin with reduced performance. The performance of ion exchange resins deteriorates due to organic contamination due to long-term use. The operation to restore this reduced performance is regeneration.
[0002]
[Prior art]
When adsorbing and removing weakly basic organic substances such as aniline or weakly acidic organic substances such as phenol contained in polar liquids such as hydrous ε-caprolactam with ion exchange resins, ion exchange resin Adsorption capacity decreases. Regeneration of ion-exchange resins with reduced performance is generally treated with warm saline, but ion-exchange resins contaminated with organic liquids by treating polar liquids such as hydrous ε-caprolactam cannot be regenerated by this method. Therefore, it had to be replaced with a new resin.
[0003]
[Problems to be solved by the invention]
Therefore, there is a need for a simple method for regenerating an organic contaminated ion exchange resin.
[0004]
[Means for Solving the Problems]
The above-mentioned problem is solved by a regenerative method characterized in that an ion exchange resin having a reduced performance is brought into contact with a hydrous polar solvent in which sodium chloride is dissolved.
[0005]
Hereinafter, the configuration of the present invention will be described in detail.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Alcohols such as ethanol, isopropanol Specific examples of polar solvents, acetic acid, organic acids such as propionic acid, sulfoxides represented by dimethyl sulfoxide, N, N- dimethylformamide, chain or cyclic amides such as ε- caprolactam Although class is Ru and the like, lactams in the present invention, dimethyl sulfoxide or dimethylformamide, is used. Of these, dimethyl sulfoxide, N, N-dimethylformamide, and ε-caprolactam are preferable, and ε-caprolactam is particularly preferable.
[0007]
In the present invention, the concentration of sodium chloride dissolved in the hydrous polar solvent is usually from 0.1% by weight to 20% by weight, but it is desirable that the concentration be less than the saturation solubility in the hydrous polar solvent. For example, when an ε-caprolactam aqueous solution is used as the hydrous polar solvent, the relationship between the water fraction and the saturated salt concentration is expressed by the formula (1).
[0008]
Y = 5.09X + 46.1X ² (1)
In the formula (1), Y is a saturated salt concentration (% by weight of salt with respect to the solution), and X is a moisture content (weight fraction of water in the ε-caprolactam aqueous solution).
[0009]
In the present invention, the ion form of the ion exchange resin may be H form (cation exchange resin) or OH form (anion exchange resin), but it is previously contacted with a saline solution to form Na form (cation exchange resin) or Cl form. After changing to (anion exchange resin), it can be regenerated by contacting with a hydrous polar solvent in which sodium chloride is dissolved.
[0010]
In the present invention, the water concentration in the hydrated polar solvent is preferably 10 to 90% by weight.
[0011]
The temperature of regeneration carried out in the present invention is usually in the range of 30 ° C. to 120 ° C. in the case of a cation exchange resin, but is carried out at 30 ° C. to 80 ° C. in the case of an anion exchange resin alone or mixed with a cation exchange resin. It is desirable to do.
[0012]
In the present invention, the amount of the hydrous polar solvent in which the salt to be contacted at one time is usually preferably 0.5 to 20 parts by volume with respect to the ion exchange resin.
[0013]
The ion exchange resin used in the present invention may be any of strong acid cation exchange resin, weak acid cation exchange resin, strong base anion exchange resin, weak base anion exchange resin, and gel type and porous type. Any of these may be used. The regenerative operation may be carried out by cation exchange resin and anion exchange resin alone or by mixing both, and the contact between the resin and the regenerative liquid can be carried out by a column flow system or a stirring tank mixing system. Further, the regenerative operation can be carried out in one stage or repeatedly in multiple stages by changing the liquid.
[0014]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.
[0015]
In this example, the performance evaluation of the ion exchange resin was carried out by uniformly mixing 10 ml of cation and anion exchange resin into an ion exchange column (inner diameter 1 cm) with a warm water jacket, and an ε-caprolactam aqueous solution containing 50 ppm of aniline. (Water concentration 12.5% by weight) When passing through at a passing temperature of 40 ° C. and a superficial flow rate SV = 3, the remaining aniline concentration in the effluent after passing through for 5 hours was used.
[0016]
In this example, aniline was detected by gas chromatography (stationary phase liquid: Thermon-3000, carrier: Chromosorb W (AW-DMCS), column: 2 m glass, detector: hydrogen flame, detection limit of aniline = 0.3 ppm). I went there.
[0017]
Reused product of the ion exchange resin used in this example and a resin whose performance deteriorated due to long-term use (a cation exchange resin was passed through a 10% by weight hydrochloric acid aqueous solution for 1 hour at a superficial flow rate of SV = 3). Then, the anion exchange resin is regenerated to the OH form by passing 5% by weight of caustic soda aqueous solution at the superficial flow rate SV = 3 for 1 hour, and the deionized water is fed to the superficial flow rate SV. The concentration of aniline in the effluent after 5 hours of passing through (= 10 for 1 hour and washing) was below the detection limit (≦ 0.3 ppm) and 12.5 ppm, respectively.
[0018]
Example 1
Macroporous strongly acidic cation exchange resin (Lebatit SP112; Mitsui Toatsu Fine Co., Ltd.) and porous strong salt-based anion exchange resin (Diaion PA 308; Mitsubishi Chemical Co., Ltd.) whose adsorptive capacity has been reduced by long-term use 30 ml each is packed separately in a 1 cm inner diameter column and 10% by weight saline is passed for 1 hour at a superficial flow rate of SV = 3 to convert the cation exchange resin into Na form and the anion exchange resin into Cl form. did. 15 ml of the above ion-exchange resin drained into a 200-ml eggplant type flask equipped with a reflux condenser was collected, and 75 ml of regenerative liquid having a composition of ε-caprolactam: water: sodium salt of 70: 27: 3 parts by weight was added to 80 ° C. For 8 hours.
[0019]
After washing the resin with water, it is packed in a glass column having an inner diameter of 1 cm. The cation exchange resin is 10% by weight hydrochloric acid aqueous solution in H form, and the anion exchange resin is 5% by weight caustic soda aqueous solution at a superficial flow rate SV = 3. The solution was passed through for a period of time to regenerate the OH form, and the ion-exchanged water was further passed through at a superficial flow rate SV = 10 for 1 hour for washing.
[0020]
10 ml each of regenerated, regenerated cation and anion exchange resins are collected, uniformly mixed and packed in an ion exchange column with a warm water jacket (inner diameter 1 cm), and an ε-caprolactam aqueous solution (moisture concentration of 12.5) containing 50 ppm of aniline. (Weight%) was passed through at a liquid passing temperature of 40 ° C. and an empty liquid passing speed SV = 3. The aniline concentration in the effluent after passing through for 5 hours was 0.9 ppm.
[0021]
Comparative Example 1
The regenerated solution was treated in the same manner as in Example 1 except that the aqueous solution was changed to an ε-caprolactam aqueous solution (water concentration 30% by weight) containing no salt. The aniline concentration in the effluent after passing through for 5 hours was 12 ppm.
[0022]
Comparative Example 2
The regenerated solution was treated in the same manner as in Example 1 except that the regenerated solution was changed to 10% by weight saline without ε-caprolactam. The aniline concentration in the effluent after passing through for 5 hours was 12.5 ppm.
[0023]
【The invention's effect】
According to the present invention, an organic-contaminated ion exchange resin that cannot be regenerated in the past can be regenerated by a simple method of contacting with a polar hydrous solvent in which sodium chloride is dissolved. Costs and industrial waste generation can be reduced.

Claims (8)

When regenerating an organic-contaminated ion exchange resin by adsorbing and removing trace organic components contained in a polar solvent, the ion exchange resin is regenerated by contacting the ion exchange resin with a hydrous polar solvent in which sodium chloride is dissolved , A method for regenerating an ion exchange resin, wherein the hydrous polar solvent is a lactam aqueous solution, a dimethyl sulfoxide aqueous solution, or a dimethylformamide aqueous solution . 2. The method for regenerating an ion exchange resin according to claim 1, wherein the ion exchange resin is previously brought into contact with a saline solution and then brought into contact with a hydrous polar solvent in which the salt is dissolved. The method for regenerating an ion exchange resin according to claim 1 or 2, wherein the ion exchange resin is organically contaminated by adsorbing and removing aniline contained in the ε-caprolactam aqueous solution . The method for regenerating an ion exchange resin according to any one of claims 1 to 3, wherein the concentration of sodium chloride dissolved in the hydrous polar solvent is 0.1 wt% to 20 wt%. The method for regenerating an ion exchange resin according to any one of claims 1 to 4, wherein the moisture concentration of the hydrous polar solvent is 10 wt% to 90 wt%. When regenerating the cation exchange resin, the contact temperature is 30 ° C to 120 ° C. When regenerating the anion exchange resin, 30 ° C to 80 ° C. When regenerating the mixture of the cation exchange resin and the anion exchange resin. It is 30 degreeC-80 degreeC, The regeneration method of the ion exchange resin of any one of Claims 1-5. The method for regenerating an ion exchange resin according to any one of claims 1 to 6, wherein the amount of the hydrous polar solvent in which the salt to be contacted is 0.5 to 20 parts by volume with respect to the ion exchange resin. The method for regenerating an ion exchange resin according to any one of claims 1 to 7, wherein the hydrous polar solvent is an aqueous ε-caprolactam solution.