JPS6359743B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses a strongly basic anion exchange resin (hereinafter referred to as
The present invention relates to a method for stabilizing exchange resins (abbreviated as "exchange resins"), and more specifically, relates to methods for stabilizing exchange resins mainly used in pharmaceutical water purifiers. In recent years, with the increase in water demand, ion exchange resins have been widely used for softening and purifying industrial water, domestic water, etc. In particular, exchange resins for water purification equipment used for purification purposes have safety concerns. From this point of view, the ability to stably supply high-purity water has been strongly desired from the beginning. Generally, exchange resins are known to undergo natural deterioration phenomena such as decomposition of exchange groups and weak basicization of quaternary ammonium salts due to their chemical properties. That is, the exchange resins called I-type resin and type resin change as shown in the following formulas and undergo natural deterioration. Type I resin (1) Decomposition of exchange group (2) Weak basicization Type resin (1) Decomposition of exchange group (2) Weak basicization (R is an organic group that is a polymer base) In addition to these compounds, acetaldehyde, dioxane,
It is also known that ethyl alcohol is produced. When these impurities are installed in an actual machine and used, these impurities may get mixed into the treated water, or cause a decline in the functionality of the exchange resin due to concurrent weak basification, especially during initial elution during water flow. This phenomenon becomes noticeable at times. Conventionally, the only way to deal with these drawbacks of replacement resin is to secure a large amount of pure water for cleaning before water sampling, fill the actual machine with the replacement resin, and then perform water flow cleaning for a long period of time. Nakatsuta. Furthermore, this phenomenon of natural deterioration is more pronounced in type resin than in type I resin, leading to a tendency to use type I resin instead of type resin, but its function as a replacement resin is better than type I resin. The type resin is extremely superior, and it is extremely difficult to convert existing discarded mold resin equipment to use type I resin in light of design standards and the like. For this reason, in the industry, there are no impurities mixed into the treated water, and
In addition, there has been a desire for a method that can maintain the exchange function. The purpose of the present invention is to solve the above-mentioned problems.More specifically, the purpose of the present invention is to prevent the generation of impurities by artificially degrading recycled replacement resin to an appropriate degree before use, and to prevent the generation of impurities. This provides a method for stabilizing exchange resins that is excellent in preventing functional deterioration. As a result of intensive research into replacement resins with low initial deterioration, that is, replacement resins with excellent stability, the inventor found that applying an appropriate heat treatment to the recycled replacement resin is extremely effective in suppressing natural deterioration during the initial period of water flow. Having obtained the knowledge that the method is effective, the present invention has been completed. That is, the method for stabilizing an exchange resin of the present invention is characterized in that the exchange resin is made into a regenerated type and then heat-treated in the presence of water. The exchange resin used in the present invention is not particularly limited as long as it is commonly used. That is, the general formula:

[Formula] (wherein R represents an organic group and X represents an anionic group) So-called type I resin and general formula:

A so-called mold resin represented by the formula: (wherein R and X are the same as the groups described above) is preferred, and the latter type resin is more preferred. Here, a preferred specific example is that R is a polymer base based on a copolymer of styrene and divinylbenzene (DVB), and X is a chlorine atom. In the present invention, making the exchange resin a recycled type means
Generally, commercially available exchange resins are of the chemically stable type where X=Cl in the above general formula, and when used, resins of this type are treated with a sodium hydroxide aqueous solution or other conventional methods. X in the general formula
= means to exchange to OH type. In the present invention, the heat treatment must be carried out in the presence of water in order to elute impurities, and the type of treatment at that time is not particularly limited as long as it is commonly carried out. The conditions for this heat treatment are that the temperature is 85
The range is preferably 100°C, more preferably 90°C
The temperature is 95°C, and the required time is preferably in the range of 2 to 10 hours, more preferably 3 to 8 hours. If this temperature is less than 85°C, it will take a long time to degrade the resin appropriately, and if it exceeds 100°C, bumping will occur at normal pressure, which is not preferable. In addition, if the time is less than 2 hours, the progress of deterioration is slow and stabilization is insufficient, and if it exceeds 10 hours, artificial deterioration will progress too much and the ion exchange capacity will be reduced more than necessary. Undesirable. EXAMPLES Below, examples of the present invention will be given and explained in more detail. Example: Prepare for heat treatment using an electric heater, a beaker with a capacity of 1, a tall beaker with a capacity of 0.5, and 300 g of water.
Mold resin obtained by pouring 360ml of (2.5N) sodium hydroxide (NaOH) (manufactured by Mitsubishi Chemical Industries, Ltd.)
SA20AP) 120ml was heat-treated at 90°C for 8 hours with 200ml of water. Then, the resin after heat treatment
Fill 100ml into a glass column and add 2.5N again.
Pour 360 ml of NaOH, extrude with distilled water, wash, leave it as it is overnight, wash with distilled water for about 1 hour (space velocity (SV): about 20 hours ^-1 ), and sample the washing wastewater at this time. I did it. Furthermore, 100 ml of this washed resin and 50 ml of cation exchange resin (SK-1B manufactured by Mitsubishi Chemical Industries, Ltd.: recycled and washed) were mixed, and this mixture was mixed with raw water (city water with 2.5 ppm of sodium sulfite). Water that has been treated to reduce residual chlorine) is passed for 3 hours to be treated (SV: approximately 13 hours).
^-1 ) At this time, treated water sampling was conducted. Comparative Example A comparative example was prepared in the same manner as in the example except that SA20AP without heat treatment was used. The Nessler method (Japanese Pharmacopoeia, 9th revised edition: Purified water ammonium test method) was adopted as the evaluation standard.
That is, the presence or absence of detection of eluates was determined by visual observation and absorbance measurement (wavelength: 410 nm, thickness: 20 mm cell) of sample treated water (sample: Nessler reagent = 50 ml: 0.5 ml). Next, the results of the elution determination test during washing (Table 1),
The elution determination test results during water flow (Table 2) and resin analysis results (Table 3) are shown.

【table】

【table】

[Table] As detailed above, the exchange resin according to the present invention has much better stability than conventional products because the initial elution of impurities is extremely suppressed and the exchange resin is maintained. Therefore, its industrial value is great.

Claims (1)

[Scope of Claims] 1. A method for stabilizing a strongly basic anion exchange resin, which comprises making the strongly basic anion exchange resin into a regenerated type and then heat-treating it in the presence of water. 2 Strongly basic anion exchange resin has the general formula: (wherein, X represents an anion group) A method for stabilizing a strongly basic anion exchange resin according to claim 1, wherein the resin has an exchange group represented by the following formula.