JP2891790B2 - Regeneration method of anion exchange resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating an anion exchange resin used in the production of pure water, and more particularly to a method for regenerating T.A. O. C. Among the C components, certain T. elegans that are desorbed immediately before the end of water flow when an anion break occurs. O. C component can be effectively eliminated, and the T.C. O. The present invention relates to a method for regenerating an anion exchange resin capable of preventing the residual and accumulation of the C component.

[0002] comprising a combination of a cation exchange resin and an anion exchange resin deionized water cleaning apparatus, ultrapure water production or medical in the electronics industry, the pharmaceutical industry, has been used width widely in the production of pure water in the food industry and the like. For example, LSI and super LSI
In the electronics industry that manufactures semiconductor wafers or chips (hereinafter referred to as semiconductor wafers) that are intermediate products, in order to improve the yield,
Ion, fine particles, T.I. O. C. It requires so-called ultrapure water from which components and viable bacteria have been removed as much as possible.In the production of such ultrapure water, as described below, a pure water production apparatus using an ion exchange resin plays an important role. Play.

More specifically, an example of the production of ultrapure water will be described. To-be-treated water such as industrial water is first treated by a pretreatment device such as a coagulation sedimentation device, a sand filter, an activated carbon filter, and then, for example, by strongly acidic cation exchange. A cation tower filled with resin,
A two-bed, three-column pure water production apparatus comprising a decarbonation tower and an anion tower filled with a strongly basic anion exchange resin, or a mixture in which a mixed resin of the cation exchange resin and the anion exchange resin is filled in the tower. Treatment is carried out in a pure water producing apparatus using an ion exchange resin such as a bed type pure water producing apparatus, and the obtained pure water is treated as it is or in a reverse osmosis membrane apparatus to obtain primary pure water.

As the above-mentioned pure water producing apparatus, an apparatus having a regenerating facility is usually used. Therefore, the ion exchange capacity of the ion exchange resin filled in the column is reduced, or the pure water production reaches a specified amount. In this case, the cation exchange resin is regenerated using an acid such as hydrochloric acid, and the anion exchange resin is regenerated using an alkali such as sodium hydroxide, and pure water is produced again.

[0005] The apparatus until the primary pure water is obtained is usually referred to as a primary water supply production apparatus or a primary system. In ultrapure water production, the primary pure water obtained from the primary water supply production apparatus is further subjected to ultraviolet oxidation. Equipment, non-regenerative mixed-bed type pure water production equipment (cartridge polisher), secondary side water supply production equipment (also called subsystem) combined with ultrafiltration membrane, etc. to obtain ultrapure water by further advanced treatment. The ultrapure water is supplied to a use point and used for cleaning a semiconductor wafer.

[0006] Of the cleaning wastewater discharged from the point of use by cleaning the semiconductor wafer, those having relatively good water quality can be treated with an activated carbon device, a desalinated water producing device using ion exchange resin or a pure water producing device. Treated by a recovery system combined with an ultraviolet oxidation device and a membrane separation device such as a microfiltration membrane device, etc. O. The recovered water from which impurities such as C components and ions have been removed is returned, and the recovered water is returned, for example, to the front stage of the primary water supply manufacturing apparatus, and mixed with industrial water or the like supplied from a pretreatment apparatus to form the pure water manufacturing apparatus. It is also used as water to be treated.

[0007]

The pure water producing apparatus using the ion exchange resin installed in the ultrapure water producing apparatus or the recovery system as described above is originally contained in the water to be treated. Is installed for the purpose of removing ions that are present, sodium ions contained in the water to be treated,
Cation components such as calcium ions are adsorbed and removed by the cation exchange resin, and anion components such as chloride ion, sulfate ion and silica are adsorbed and removed by the anion exchange resin.

[0008] However, the ion exchange resin is not only capable of adsorbing and removing ions as described above, but also has a small amount of T.C. contained in water to be treated such as industrial water. O. It is known that it is also effective for the adsorption and removal of the C component. O.
When the water to be treated containing the C component is treated by a pure water production apparatus using an ion exchange resin, the T.C.
O. Pure water with a low C concentration can be obtained. And T. O. C
It is also well known that components are mainly adsorbed on anion exchange resins.

[0009] However, T. adsorbed on the anion exchange resin. O. The component C is different from ions such as chloride ion and sulfate ion adsorbed on the anion exchange resin, and is hardly desorbed by ordinary regeneration using an alkali solution. T. in exchange resin O. The C component gradually accumulates.

That is, the anion exchange resin used in the pure water production apparatus uses an alkali solution such as a sodium hydroxide solution as described above when the process of passing the water to be treated, that is, the process of collecting pure water, is completed. To remove impurity ions and the like adsorbed in the water passing step. At this time, chlorine ions, sulfate ions, silica and the like can be almost completely desorbed. O. The C component is not completely desorbed, and the adsorbed T.C. O. Part or most of the component C remains in the regenerated anion exchange resin.

This T. O. The component C is derived from organic substances contained in the water to be treated, and includes various kinds of organic substances from high-molecular organic substances to low-molecular organic substances. T. consisting of these organic substances O. The behavior of the component C with respect to the anion exchange resin varies depending on its molecular weight and the adsorption characteristics with respect to the anion exchange resin. Once adsorbed, it is treated with a heated sodium chloride-sodium hydroxide mixed solution or desorbed unless treated with an oxidizing agent. T. O. If a water-flow method is adopted in which the component C (referred to as TOC component-1 for convenience) and an anion break, that is, almost no OH-type anion exchange resin remains in the water, the T desorbs immediately before the end of the water flow. . O. C component (for convenience, referred to as TOC component-2).

T. O. Component C-1 is strongly firmly adsorbed on the anion exchange resin, so that the exchange capacity and the reaction rate decrease. O. Although the problem of increasing the C concentration does not occur, the T.C. O. Component C-2 sometimes poses a serious obstacle.

That is, in designing the pure water production apparatus, the cation exchange resin usually reaches the flow-through point before the anion exchange resin, so that the anion exchange resin still flows through so that a cation break occurs. Point, but sometimes the anion exchange resin reaches the cross-flow point before the cation exchange resin due to fluctuations in water quality or a decrease in the exchange capacity of the anion exchange resin. There is. Such a state is referred to as an anion break as described above, and T.A. O. C component-2 is desorbed at a time, and T.C.
O. There is a problem that the C concentration abnormally increases. In addition, T.A. O. When the C component-2 accumulates in a considerably large amount, even if it does not cause an anion break, it tends to be desorbed in a small amount during normal water flow,
Therefore, T. of treated water O. There is also a problem that the C concentration increases.

[0014] Therefore, in the water-passing step, T. adsorbed on the anion exchange resin. O. If Component C-2 can be effectively eliminated in the regeneration step, T.C. O. It is possible to prevent the accumulation of the C component-2, and even if the anion break occurs, the T.C. O. The problem that C concentration increases abnormally,
T. during normal water flow O. Although the problem of an increase in the C concentration can be avoided, the above-mentioned T.C. O. C
It is difficult to completely remove component-2.

[0015] The present invention has been made under such a background, and the T.V. O. Effectively desorb C component-2,
T. O. It is an object of the present invention to provide a method for regenerating an anion exchange resin capable of minimizing the accumulation of component C-2.

[0016] The method for regenerating an anion exchange resin of the present invention, which has been made to achieve the above object, comprises the steps of:
When it is raised, it will be released into the treated water just before the end of the water flow.
Such as T. O. C. Raw water containing ingredients
Upon reproducing the anion exchange resin was used to water purification and treatment, and after passing water ends, the contacting the hydrochloric acid solution to the anion exchange resin T. O. C. Remove the ingredients
And then regenerate by contacting with an alkaline solution.

[0017]

The present invention will be described below in detail. The present inventors have determined that the above T.A. O. As a result of intensive studies on the method of desorbing the component C-2, it was found that the desorption can be performed extremely effectively by bringing the acid solution into contact with the anion exchange resin after the completion of water passage.

[0018] As the acid to be contacted with the anion exchange resin, hydrochloric acid, sulfuric acid, may be used, nitric acid, pure
Hydrochloric acid is used for regeneration of cation exchange resin in water production equipment.
Since it is common to use the same hydrochloric acid, it is preferable to use the same hydrochloric acid.
Properly, and as a concentration when contacting a suitably about 1-10%. Such concentration of hydrochloric acid solution (hereinafter simply
The “acid solution” is brought into contact with the anion exchange resin by passing it through the anion exchange resin immediately after the completion of the water supply at a relatively low flow rate such as SV 2 to 10, and is adsorbed on the anion exchange resin. T. O. C
Component-2 is eliminated. Note that the desorption operation may be performed at normal temperature or under heating.

The amount of the acid solution used is not less than the chemical equivalent of the OH type anion exchange resin present in the anion exchange resin before contacting the acid solution. It is preferable to use at least the chemical equivalent of the anion exchange resin, and when the amount of the acid solution used is smaller than this, most of the used acid remains in OH
Is consumed in the neutralization reaction with the anion exchange resin,
As a result, T.I. O. C component-2 is not sufficiently desorbed.

After finishing the passing of the acid solution as described above,
Pure water is passed through the anion exchange resin layer to wash it sufficiently.
Next, an alkaline solution such as a sodium hydroxide solution is passed through and brought into contact with the anion exchange resin layer to regenerate into an OH form, which is again provided for production of pure water.

In the case of an anion exchange resin treated with water to be treated containing a relatively large amount of silica, if an acid solution is immediately brought into contact with the anion exchange resin after the completion of water passage, the silica adsorbed on the anion exchange resin is May be gelled, which may lead to undesired results such that silica is not completely desorbed even after regeneration using an alkaline solution.In such a case, before contacting the acid solution, the anion exchange resin may be used. Most of the silica may be desorbed in advance by bringing an alkali solution such as sodium hydroxide into contact with the solution, and then an acid solution may be brought into contact. Even when such a method is adopted, the T.V. O. The elimination of the C component-2 is performed without any problem.

However, when the alkali solution is brought into contact with the acid solution in advance before the acid solution is brought into contact with the alkali solution as described above, chlorine, sulfate ions, etc. including silica adsorbed on the anion exchange resin are brought into contact with the alkali solution. Partially desorbed, the amount of the OH-type anion exchange resin increases by that much more than at the end of the passage of water. There is a need to.

The above-mentioned regeneration method of the present invention is desirably carried out every time in each cycle. O. Although the residual and accumulation of the component C-2 can be most effectively prevented, in some cases, the regeneration method of the present invention and the conventional regeneration method without performing the step of contacting with an acid solution are alternately performed. Or a method in which the reproducing method of the present invention is performed once every three to five times of the conventional reproducing method.

The regeneration method of the present invention is effective for both strongly basic and weakly basic anion exchange resins. Therefore, a two-bed, three-column pure water production apparatus comprising a cation tower filled with a strongly acidic cation exchange resin, a decarbonation tower, and an anion tower filled with a strongly basic anion exchange resin, Multi-layer pure water production by laminating a weakly acidic cation exchange resin and a strongly acidic cation exchange resin, and laminating and filling a weakly basic anion exchange resin and a strongly basic anion exchange resin in an anion tower. apparatus,
Alternatively, the present invention can be applied to any type of pure water production apparatus such as a mixed bed pure water production apparatus in which a strongly acidic cation exchange resin and a strongly basic anion exchange resin are mixed and packed in the same column.

As described in detail above, according to the present invention, T.V.
O. Of the C components, T. is relatively easily desorbed such that when an anion break occurs, it is desorbed immediately before the end of the water flow. O. The C component, it is possible to effectively eliminated by solution hydrochloric acid, thus such T. O. The accumulation of the component C in the anion exchange resin can be prevented.

As a result, even if the pure water production apparatus is in an anion break, the T.V. O. The problem of an abnormal increase in the C concentration was solved, and T.C. O. It becomes possible to always obtain treated water having a low C concentration.

[0027]

Embodiments of the present invention will be described below. Using a two-bed, three-tower pure water production apparatus that obtains pure water by passing the water to be treated in the order of a cation tower, a decarbonation tower, and an anion tower, while performing the regeneration method of the present invention every time, Cation break always at the end (the residual R-OH of the anion tower at the time of the cation break was 0.35 eq / L-resin)
Pure water was produced under the following conditions.

(1) Ion exchange resin used Strongly acidic cation exchange resin Amberlite IR-124 (new) 5 L Strongly basic anion exchange resin Amberlite IRA-402BL (new) 10 L (2) Average T.W. O. C concentration 600μg / L (3) Water sampling amount 2,500L / cycle

(4) Regeneration conditions Strongly acidic cation exchange resin 35% hydrochloric acid 73 g / L-resin (0.7 eq / L-resin) Strongly basic anion exchange resin (A) Acid solution passing step (liquid passing-1) (Process consisting of passing acid solution → extruding → washing) Amount of acid used 35% hydrochloric acid 210 g / L-resin Passing concentration 5% Passing speed SV = 4 Extrusion and washing were performed using pure water. Washing was performed at SV = 12 for 15 minutes.

(B) Passing step of NaOH solution (passing-2) After passing through liquid-1, the NaOH solution was passed and regeneration was carried out by an ordinary method. NaOH usage 100% NaOH 140g / L-resin Flow rate 4% Flow rate SV = 4

After 20 cycles of the production of pure water under the above-described conditions, in the next 21-th water-flowing step, a small amount of hydrochloric acid solution is continuously injected into the outlet water of the decarbonation tower to form an anion exchange resin. Pure water production was carried out to increase the ionic load on, and to intentionally cause an anion break.
FIG. 1 shows the result of water passage at this time. In FIG. 1, the horizontal axis represents the amount of treatment (L), and the vertical axis represents the T.V. in treated water (pure water). O. The C concentration (μg / L) is shown.

As shown in FIG. O. Although the C concentration was stable at about 25 μg C / L at first, it is recognized that the C concentration was slightly increased at around 1,500 L of the treatment amount where an anion break was considered to have occurred.
However, the T.W. O. The C concentration is at most about 50 μg C / L, and the increase is extremely small.

[0033]

[Comparative Example] For comparison, another series of a two-bed, three-tower type pure water production apparatus of the same scale as that used in the above example was prepared. 20 cycles of pure water production employing the conventional regeneration method in which only the "passage-2" was performed without performing the solution passage step) were performed in parallel with the above-described embodiment.

Thereafter, in the next 21-th water-flowing step, a hydrochloric acid solution is continuously injected into the outlet water of the decarbonation tower in the same manner as in the above embodiment to produce pure water in which an anion break is intentionally generated. Was done. FIG. 2 shows the results of water passage.

As can be seen from FIG. 2, in the case of this comparative example in which the conventional regeneration method was performed for 20 cycles, the T.V. O. The C concentration increased remarkably as compared to before, and increased up to about 900 μg C / L.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of passing water in an example.

FIG. 2 is a graph showing a result of passing water in a comparative example.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Higashi 1-4-9 Kawagishi, Toda City, Saitama Prefecture Inside Organo Research Institute (72) Inventor Koichi Tanabe 1-4-9 Kawagishi, Toda City, Saitama Prefecture (56) References JP-A-60-14942 (JP, A) JP-A-60-248239 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01J 49/00 C02F 1/42

Claims (2)

(57) [Claims] (1) When an anion break occurs, the
Relatively desorbs into the treated water just before the end of water
T. O. C. Pure water production by treating raw water containing ingredients
Upon reproducing the anion exchange resin was used to, after passing water ends, by contacting a hydrochloric acid solution to the anion exchange resin the T. O. C. A method for regenerating an anion-exchange resin, comprising removing components and then regenerating by contacting with an alkaline solution. 2. The anion exchange according to claim 1, wherein the amount of the hydrochloric acid solution to be brought into contact with the anion exchange resin is not less than the chemical equivalent of the OH type anion exchange resin present in the anion exchange resin before contact with the hydrochloric acid solution. How to regenerate resin.