JPS605231A - Stabilization of strong basic anion exchange resin - Google Patents

Abstract

PURPOSE:To obtain an exchange resin reduced in initial deterioration, by applying heat treatment to a regenerable type strong basic anion exchange resin in the presence of water. CONSTITUTION:A strong basic anion exchange resin is made regenerable to be subjected to heat treatment at about 85-100 deg.C, pref., about 90-95 deg.C for about 2-10hr, pref., about 3-8hr in the presence of water to effectively suppress natural deterioration at the early stage in passing water. In this case, the exchange resin pref. has an exchange group represented by formula (wherein X represents an anion group).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for stabilizing a strongly basic anion exchange resin (hereinafter abbreviated as "exchange resin"). Concerning the law.

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 ``type resin'' and ``type resin'' change as shown in the following equations and undergo natural deterioration.

■Type resin (1) Decomposition of exchange group R-C-N (CHs)s→R-C'H, -OH+
($)3 NH (2) Weakly basic RCH2N (CH3)s→R-CHt-N(CHs)
z+cFIsOHH ■Type resin (1) Decomposition of exchange group (2) Weak basicization (R is an organic group that is the polymer base) In addition to these compounds as impurities during this natural deterioration, acetaldehyde, dioxane, ethyl alcohol, etc. generation is also known. These impurities may be mixed into the treated water when the exchange resin is installed in an actual machine, and may also cause a decline in the function of the exchange resin due to weak basification. This phenomenon becomes noticeable during elution.

Conventionally, as a countermeasure to these drawbacks of replacement resin, a method has been used in which a large amount of pure water for cleaning is secured in advance before water sampling, and after filling the actual machine with replacement resin, the water is passed through and cleaned for a long period of time. There was only one. Additionally, this phenomenon of natural deterioration is more pronounced in ■-type resins than in ■-type resins, leading to a tendency to use I-type resins instead of ■-type resins, but the function of ■-type resins as replacement resins is The ■-type resin is much superior to the
It was extremely difficult to change the ji to a type resin and use it in light of design standards and the like. For this reason, there has been a desire in industry for a method that does not introduce impurities into treated water and can maintain the exchange function.

The purpose of the present invention is to solve all of the above problems,
More specifically, by artificially deteriorating the recycled exchange I21 resin to an appropriate degree before use, we can prevent the generation of impurities and stabilize the exchange resin, which is excellent in preventing deterioration of the exchange function. will provide the law.

As a result of repeated research into replacement resins with low initial deterioration, that is, replacement resins with excellent stability, the present inventor found that moderate heat treatment of recycled replacement resins suppresses natural deterioration during the initial period of water flow. The present invention was completed based on the knowledge that the present invention is extremely effective.

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. In other words, it is represented by the general formula: RCHt N(CHs)s (wherein, RR represents an organic group, and X represents an anionic group) (wherein, R and X are the same as the above-mentioned groups). The so-called ■-type resin is preferable, and the latter type ■type resin is more preferable. Here, to give a preferred specific example, R is a polymer base based on a copolymer of styrene and divinylbenzene (D, V, B), and X is a chlorine atom.

In the present invention, the exchange resin is made into a regenerated type, which means that generally commercially available exchange resins are of the type where X = Ct in the above general formula, which is chemically stable, and this type of resin is hydroxylated before use. This means changing to the form of X=OH in the above general formula by a conventional method such as treatment with an aqueous sodium solution.

In the present invention, the heat treatment must be performed in the presence of water in order to elute impurities, and the treatment format at that time is not particularly limited as long as it is commonly performed. The conditions for this heat treatment are such that the temperature is preferably in the range of 85 to 100°C, more preferably 90 to 95°C, and the required time is preferably in the range of 2 to 10 hours, even more preferably 3 to 100°C.
It is 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. Additionally, 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 has progressed too much and the ion exchange capacity may be reduced more than necessary. This is not desirable because it causes

EXAMPLES Below, examples of the present invention will be given and explained in more detail.

Example 941 Heat treatment was prepared using a beaker with a capacity of 1 ton of fireflies, a tall beaker with a capacity of 10.5 ton, and 300 liters of water.
, 5N) sodium hydroxide (NaOH) 360- type resin (Mitsubishi Chemical Industries (llll:,
) 5A20AP) 120- with 200fnt of water 9
Heat treatment FT at 0℃ for 8 hours! , e was applied. Next, the heat-treated resin 100- was filled into a glass column, and 360 ml of 2.5 N NaOH was again poured into the column, extruded and washed with distilled water, and left in the apparatus overnight, followed by washing with distilled water for about 1 hour. Space velocity (SV): about 20 hours),
At this time, cleaning wastewater sampling was carried out. Furthermore, 100 ml of this washed resin and 50 fn of cation exchange resin (5K-IB manufactured by Mitsubishi Chemical Industries, Ltd.: recycled and washed)
SV: about 13 hours-1).
At this time, treated water was sampled.

Comparative Example A comparative example was prepared in the same manner as in the example except that 5A20AP 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, sample treated water (Sandel: Nessler reagent =
The presence or absence of detection of eluates was determined by visual observation and absorbance measurement (wavelength: 410 nm, thickness: 20 m cell).

Next, the results of the elution determination test during washing (Table 1), the results of the elution determination test during water passage (Table 2), and the resin analysis results (Table 3) are shown.

As detailed above in Table 1, Table 2, and Table 3, the exchange resin according to the present invention has extremely suppressed initial elution of impurities and maintains the exchange function, so its stability is higher than that of conventional products. It is much superior to the conventional method, and 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 strong basic anion exchange resin into a regenerated type and then heat-treating it in the presence of water. 2. The strongly basic anion exchange resin according to claim 1, wherein the strongly basic anion exchange resin is an exchange group represented by the general formula: (wherein, X represents an anion group) Resin stabilization method.