JPS5992028A - Ion exchange treatment - Google Patents

Abstract

PURPOSE:To enhance the contact efficiency of a liquid to be treated and a resin particle, by a method wherein ion exchange resin is held in a container for holding ion exchange resin while passing a liquid to be treated and said container is immersed in the liquid to be treated to repeatedly recirculate said liquid to be treated through said container. CONSTITUTION:A liquid to be treated is put in a treating tank 2 and a container 4 having a predetermined amount of ion exchange resin 3 held therein is immersed in said liquid 1 to be treated. A proper recirculation stream means, for example, a barrier plate 5 and a stirrer 6 are provided in a treating tank 2 to form a rising stream in the holding container and ion exchange resin particles are floated. The holding container is one comprising a reticulated or a porous material having a volume 1.5-1,000 times by volume of the ion exchange resin required in deionizing the ion in the liquid 1 to be treated and a basket comprising a material passing the liquid to be treated but capable of holding the ion exchange resin particle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion exchange treatment method using an ion exchange resin.

Ion exchange methods using ion exchange resins include stirring method,
Fluidized bed type, moving bed type, fixed bed type, etc. are known.

Since the stirring type is used with the resin dispersed in the processing liquid, the contact efficiency between the resin particles and the processing liquid is high, but because the particles are seriously damaged by stirring, it is currently hardly used industrially. Not put into practical use. The next fluidized bed method is also used in which the ion exchange resin is suspended in the treatment solution, and the efficiency is similar to the above, but the thickness of the flowing layer is small and the desired ion exchange reaction is completed. No one! However, the treatment liquid flows out and requires a multi-stage fluidized bed, so it is only used in certain sectors. These methods are convenient when the purpose is to treat a portion of the ions in the processing solution, but if you want to completely process the ions in the processing solution, you need to purify as much as possible.
The first-order column method is considered to be appropriate in treatments aimed at purity.

In other words, the column method theoretically allows the ion exchange reaction (equilibrium reaction) between the resin and the treatment liquid to be continuously set to an infinite number of stages, and the desired ion exchange, regeneration, and cleaning can be performed in the same column. It has the advantage of being able to be carried out in a vacuum, and has been adopted as the most typical treatment method using ion exchange resins.

However, in recent years, there has been a problem of pollution due to the disposable use of regenerating and cleaning solutions, and the overall cost including wastewater treatment has increased.
With the recent development of various membrane technologies, the competitiveness of the ion exchange method itself as a purification technology is decreasing in terms of purity.

As a result of extensive research into ion exchange reactions using the column method, the present inventor discovered that the essential drawback of the column method lies in the column structure itself that fixes the ion exchange resin particles. The contact efficiency between the ion exchange resin particles and the liquid to be treated in the column is very poor, and this is thought to be mainly due to the formation of a short circuit for the treated liquid within the laminated resin particles. This causes the need to use resin.

Furthermore, with methods other than the column method, the above-mentioned stirring method, and the fluidized bed method, although the contact efficiency between the ion exchange resin particles and the liquid to be treated is good, as mentioned above, the desired ion exchange reaction may not be completed in the strained liquid. It's a waste of water and I'm having to use more resin than necessary. In both cases, a large amount of resin is used to carry out the desired ion exchange reaction.
Wash away the drippings with a large amount of regenerating chemicals and large amounts of washing water.
It is an ion exchange treatment method that was developed as one of the first proposals, and it is clearly lagging behind the needs of resource conservation, energy conservation, pollution reduction, and high quality, and is inferior to ion exchange treatment methods.

The inventors have discovered a method for treating .r-on exchange resins that does not have the above-mentioned drawbacks. That is, in the present invention, the ion exchange resin is held in an ion exchange resin holding container through which the liquid to be treated passes, and the ion exchange resin is immersed in the liquid to be treated, and the ion exchange resin is held in the holding container through which the liquid to be treated passes. An ion exchange treatment method is provided, which is characterized in that a sufficient flow is formed in a liquid to be treated so as to cause the ion exchange reaction to occur by repeatedly circulating the liquid to be treated.

The present invention will be explained below with reference to FIGS. 1 and 2.

FIG. 1 and FIG. 2 are schematic diagrams for explaining the present invention. A liquid to be treated (1) is placed in a treatment tank (2), and a holding container (4) containing a predetermined amount of ion exchange resin (3) is immersed therein. The treatment tank (2) is provided with suitable circulation flow forming means, such as a screen (5) and a stirrer (6), to form an upward flow in the holding container and suspend the ion exchange resin particles.

The holding container (4) is made of a reticulated or porous material having a volume of 1.5 to 1000 times, preferably 5 to 50 times, the volume of the ion exchange resin required to deionize the ions in the liquid to be treated (11). It is a container such as a basket made of a material that allows the liquid to be processed to pass through but can retain the ion exchange resin particles. The method of the present invention differs from the column method in that the contact area between the water to be treated and the resin particles is wide, and the exchange of liquid on the resin surface is much smoother than in the column method. The contact is repeated until the equilibrium of the ion exchange reaction is reached.

Therefore, it has the great feature that all the surfaces of the ion exchange resin particles used can be effectively utilized in a short period of time. The ion exchange resin has a particle size of 0.1 to 2, especially 0.3 to 0.7.
m or n is preferable; if it is smaller than 0.1 mm, a fine-mesh holding container must be used.
This is not preferable because it hinders the formation of circulating flow. If it is larger than 2 fl, the surface area per resin volume will become smaller.
Efficiency decreases because it becomes difficult to float. Although such results were obtained with current commercially available products, these are not the woody conditions that define the method of the present invention. It is preferable to set the treatment tank and holding container so that the resin particles are dispersed as uniformly as possible and that a uniform liquid flow is dissipated from the entire holding container to prevent local accumulation. A preferred method is to form a circulating flow upward from the bottom of the holding container to prevent the ion exchange resin particles from depositing. As shown in Figures 1 and 2, the circulation flow may be formed using a recirculating blade type stirrer through a screen or baffle plate appropriately set in the treatment tank, or by using a pump or the like. It may be formed. As mentioned above, in order to prevent local accumulation of resin particles and to form a uniform circulating flow with as little energy as possible, it is preferable that the liquid to be treated be circulated under the same horizontal plane. That is, as shown in FIGS. 1 and 2, it is preferable that the liquid level in the holding container forms substantially the same horizontal plane as the liquid level in other parts, and that the ion exchange resin particles have an upwardly directed surface. FIG. 2 is preferable because it can effectively provide flow, and these are typical embodiments of the present invention. The flow rate of the circulating flow required for the ion exchange resin particles to float varies depending on the particle size and density of the ion exchange resin, the density, viscosity, and temperature of the processing liquid, and the size and shape of the ion exchange resin holding container. , usually 0.1-500
It is between 6n/sec and 10-100m7sec is common. If the flow rate is low, it is difficult to suspend particles, leading to an embodiment equivalent to the column method. If the flow rate is high, the power consumption for agitation flow increases, so it is sufficient to determine an appropriate value, and it is not an essential condition that defines the method of the present invention.

The method of the present invention is basically a batch process, so once the system reaches an equilibrium state, the liquid to be treated is removed and the same ion exchange treatment is repeated with another treatment liquid, or the used ion exchange resin is replaced. However, it has the essential drawback that two or more stages of ion exchange treatment must be repeated in the same treatment tank. However, in the conventional stirring type or fluidized bed type, the serious drawback that the treatment liquid flows out before the reaction equilibrium of the ion exchange reaction is reached in one stage of treatment has been solved by the present invention.

In implementing the method of the present invention, a lightning meter was installed in the middle of the circulation flow path to detect changes in the specific electrical conductivity of the liquid to be treated. It is possible to accurately detect when the target has been reached. This is an important essential advantage that can compensate for the two drawbacks of the batch method.

In the column method, the point called the flow-through point, where the ions to be exchanged and adsorbed begin to leak into the effluent at a certain concentration or higher, is determined by checking the conductivity and by self-recording. The end point of this column method and the end point of the present invention are essentially different in meaning. In other words, in the column method, processing liquid flowing beyond the flow-through point causes a loss of purity in purification, so the higher the purity required, the more rigorously this quality flow must be determined. In this detection, as long as the method detects leakage, complete purification is impossible.

For this reason, it is necessary to stop the flow of liquid well in advance. In other words, in reality, the end point can only be determined through trial and error, so failures and accidents cannot be completely prevented, and the only way to correct an accident is to start over, which is extremely inefficient. - According to the Rikiki invention, there is no problem in circulating the treatment solution beyond the equilibrium of the exchange reaction, and the end point is determined based on efficiency improvement.

The method of the invention may also be carried out at elevated temperatures. The ion exchange reaction on the surface of the ion exchange resin particles is a solid phase-liquid phase interfacial reaction, and the reaction cannot be completed instantaneously like a normal homogeneous reaction. However, since the reaction is clearly a chemical reaction, it is obvious that it can be accelerated by increasing the temperature.

In the conventional column method, it is virtually impossible to keep the column itself and the ion exchange resin inside it warm, so it has not been used. In the method of the present invention, it is extremely easy to heat the treated material overnight and maintain a constant temperature, and it is possible to use the ion exchange resin at the optimum operating temperature. Moreover, it can be carried out stably even in winter. From an industrial perspective, being able to have a stable sister-in-law throughout the year is extremely meaningful.

The regeneration treatment of the used resin may be carried out in the same manner as the ion exchange treatment of the present invention. That is, the used ion exchange resin is treated with a concentrated acidic or alkali solution.
This is an ion exchange reaction in which - is exchanged, and it is no different from the method described above. However, the method of the present invention exhibits the following features in this regeneration process.

Initially, regenerating liquid is required for several stages, but since the regenerating liquid from the second and subsequent stages is used sequentially for the next regeneration, it is practically possible to consume only the regenerating liquid from the first stage.
do not have. If the content of the regenerated liquid in the first stage is inspected as necessary, it can be reused, and in the end, only the chemical equivalent to the exchange capacity of the ion exchange resin can be consumed, thereby extremely minimizing wastage of the chemical. was completed. This also reduced wastewater treatment costs, contributing significantly to cost reduction.

Furthermore, the method of the present invention exhibits even greater effects in the cleaning step after regeneration. That is, the regenerating liquid and the drug are resin particles (Te4
There are many accidents where this happens to be the source of contamination of the liquid to be treated. Special care must be taken as it may cause fatal damage. Washing by the column method is extremely inefficient and requires a long work time because a large amount of washing water must be passed through it together with O. However, according to the method of the present invention, although it is necessary to prepare the washing water in several stages at the beginning, if the washing from the first time is repeated sequentially, it becomes substantially the same as the regeneration treatment, and the number of stages of the previous regeneration treatment is reduced. becomes possible. In other words, the cleaning process is closed.
This is also a major feature of the method of the present invention. Initially, such equipment requires a considerable amount of membrane quality. The effects of the present invention will be more pronounced as the regeneration equipment is larger, so it is preferable to collect the used ion exchange resins in one place and recycle them all at once. This is fully compensated for by this, generating significant added value. This is a field where ion exchange reactions have been difficult to adopt due to the lack of wastewater treatment equipment, and the advantage of being able to carry out ion exchange reactions directly is also significant.

The method of the present invention can be applied to all fields in which ion exchange reactions have conventionally been carried out, including medicine, food, and industry; do.

[Example 1], t'J base anion exchange resin (Amberlite IR
A reaction for regenerating A-400) using NaOH is illustrated. In the apparatus shown in FIG. 1 for carrying out the method of the present invention, a sufficient reflux passage is provided in the upper part so that the horizontal direction is the same as the inside of the column. The holding tank (4) for ion exchange reaction resin is 5 tons, and the circulation system is 21. It has a total capacity of 7 tons. This was filled with pure water and circulated, and 1 ton (wet) of the above resin (Ct-type, unregenerated with a particle size of 0.38 to 0.45#) was placed in the holding tank for 7''. They floated in the particles and moved around freely without touching or sticking to each other. It was clear that the processing liquid circulated and repeatedly and efficiently contacted the particle surfaces. The above process proceeded smoothly. The equipment and conditions were adjusted, and the water used was drained.

[Regeneration reaction]

7t of IN-NaOH was charged and the above circulation was carried out. Since 1 ton of the resin particles has an exchange capacity of 1.4 equivalents, this means that 5 times the required number of alkalis was supplied. 1st
Measure the liquid specific electricity using the specific conductivity meter (7) shown in the figure.

The results of recording and measuring the conductivity are shown in A of FIG.

R-C1+ Na+0'FI-,! R-OH+ Na
+C1- As the above exchange reaction progresses, 0" decreases and Ct- increases in the treatment solution. Since Ct- has only about 1/8 of the equivalent type conductivity of 0Ff-, this exchange reaction The transition is detected by the change in conductivity. That is, as shown in Figure 4A, the time when this change disappears is considered to have reached the upper H-exchange equilibrium. During this time, the circulation speed of the processing liquid is Even if there was a slight change, it was not a big difference, but in slow circulation where particles do not float, nine long particles are fixed, and in the case of the conventional column method, a slight change remains even after 5 hours. Equilibrium was not reached. When the liquid temperature was raised to 40° C., the reaction was completed in 30 minutes, and the effect of the present invention was remarkable.

The results of renewing the regeneration liquid and performing the same operation are shown in Figure 4 IS and Figure 3.
The results of the first test are shown in Figure 4C. At the third time, almost no change in conductivity was detected. This made it possible to accurately grasp that the regeneration using I N -NaO, I-1 is at its limit even if the process is repeated any further.

Does the above play? %, 21 L, which is larger than the conventional column method. However, this regeneration solution was stored separately and reused with NaOH replenishment 1-2.

Although the first-stage regenerating liquid, which becomes extremely contaminated, is disposed of in a timely manner, it is clear that the alkali is no longer wasted, and the effects of resource conservation and pollution prevention are enormous.

[Washing process]

Next, 7 tons of pure water of lμS/cm was filled, the above circulation was performed, and changes in the specific conductivity of the internal liquid were recorded and measured. The results are shown in A of FIG. The results of updating the cleaning solution and performing the same operation are shown in 13, C, and D. In the fourth test, no conductive dust was detected at all. The regenerating solutions used for each were stored separately and reused. At this time, the alkalinity of the liquid was measured, and the first stage armpit where the alkalinity significantly increased was discarded. However, this was used to prepare the alkaline regenerating solution, and was able to substantially prevent its disposal. Although a considerable amount of cleaning liquid was initially required, 281 liters, it was a reasonably necessary amount and was not wasted. Moreover, this water is reused,
Substantially, complete cleaning can be achieved by replenishing about 7 parts.

In the same manner as Example Case 1, 1 t of strongly acidic cation exchange resin (Amberlite IR-120B) was regenerated using hydrochloric acid.

RNa+)l+CZ? RH + Na + C1 - As the above exchange reaction progresses, J- [- decreases and Na''- increases in the treatment solution. Since Na (- is only about 115 of the equivalent conductive dust of 11 mo), this exchange The progress of the reaction can be detected more clearly from the change in conductive dust than in the anion exchange reaction shown in Example 1.
An amphoteric resin with an exchange capacity of 1.9 eq was obtained.

500 d each of the ion exchange resins from the two types of regeneration tubes were mixed and placed in a holding tank of the apparatus shown in FIG. When this was filled with tap water having a specific conductivity of 250 μS/α and circulated, the value reached 0.2 μS/crr+ after approximately 20 minutes. Water with such high specific resistance is at a level that cannot be obtained in such a short time using conventional ion exchange methods, and is a major feature of the present invention. Deionized water with guaranteed quality can be obtained batchwise, which is extremely convenient for industrial quality control, and there is no chance of defects or failures, resulting in extremely stable and highly purified deionized water. was available. It is not necessarily an advantage to be able to produce pure water in a continuous manner, but a batch method for each unit used is preferable for quality control.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams of the apparatus for carrying out the method of the present invention, Figure 3 is a schematic diagram of the column, and Figure 4 is the change in conductivity when the ion exchange resin is regenerated by the method of the present invention. , and FIG. 5 are diagrams showing changes in specific electrical conductivity during the cleaning process of Example 1. In the figure, (11) is the liquid to be treated, (2) is the treatment tank, (3) is the ion exchange resin, (4) is the holding container, (5) is the screen, (
6) is a stirrer, (7) is a conductivity gauge, (8) is a column, and (9) is a buoy/letter. In Figure 4, (A), (
B) and (C) show the change in type conductivity over time during one-stage regeneration, two-stage regeneration, and three-stage regeneration, respectively, when the Or type ion exchange resin was regenerated using the method of the present invention.

Claims (1)

[Claims] (1) Holding the ion exchange resin in an ion exchange resin holding container through which the liquid to be treated passes through which the ion exchange resin is held;
The ion exchange resin is immersed in the liquid to be treated, and a sufficient flow is formed in the liquid to cause the ion exchange resin to float in the holding container.
An ion exchange treatment method characterized in that the liquid to be treated is repeatedly circulated to cause an ion exchange reaction. 2. The method according to item 1, wherein the liquid level of the liquid to be treated in the holding container and other parts are substantially the same horizontal plane. 3. The method according to item 1, wherein reaching the reaction equilibrium of the ion exchange reaction is detected by no longer changing the electrical conductivity. 4. The method according to item 1, which is carried out by adding salt to the liquid to be treated. 5. When the reaction equilibrium of the ion exchange reaction is reached, either remove the liquid to be treated and repeat the same ion exchange reaction with another treatment liquid, or take out the ion exchange resin and use a similar treatment tank filled with a separate treatment liquid. 2. The method according to item 1, wherein the ion exchange reaction is repeated in multiple stages. 6. The method according to item 1, wherein the ion exchange reaction includes a regeneration and washing step.