JPS6142336A - Regeneration of powdery anion exchange resin - Google Patents

Abstract

PURPOSE:To eliminate a problem such as the increase in running cost or the disposal of a used resin, by contacting a powdery anion exchange resin adsorbing a substance to be adsorbed with a heated aqueous acid solution to enable the reuse of the powdery anion exchange resin. CONSTITUTION:A powdery anion exchange resin with a particle size of 250mum or less, which was used in the purification of a solution containing a coloring matter component or suspended substance to adsrob a substance to be adsorbed, is contacted with a 0.1'5% aqueous acid solution (e.g., a hydrochloric acid solution) heated to 40 deg.C or more. At first, said anion exchange resin is contacted with the 0.1-5% aqueous acid solution heated to 40 deg.C or more while the treated resin is washed with a 0.1-1% alkaline aqueous solution (e.g., a NaOH solution). By this method, regeneration can be simply performed and the reuse of the powdery anion exchange resin is enabled and a problem such as the increase in running cost or the disposal of a used resin can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to the pigment components of solutions that are colored with high color values and which contain impurities mainly turbid substances such as colloidal substances and suspended solids, as well as the turbid substances. This invention relates to a method for regenerating powdered anion exchange resin used for removal.

[Conventional technology]

It has been known that anion exchange resins are effective not only for desalination but also for decolorization, and are used, for example, in the decolorization process in the sugar refining industry.

In terms of usage, the particle size is generally 0.3~
It is known that an adsorption tower is filled with 0.6 mm granular anion exchange resin, and a liquid to be treated is passed through the packed bed to adsorb a dye component in the solution.

This method of passing the liquid to be treated through the packed bed is relatively easy to operate because the liquid is simply passed through the packed bed, but on the other hand, the adsorption surface area is small and the adsorption rate is slow, so the rate of liquid passing must be reduced. It has the disadvantage that it cannot be made very fast. For this reason, the adsorption tower tends to be relatively large, and the utilization rate relative to the theoretical adsorption capacity is also relatively small. Furthermore, if a suspended substance coexists in the liquid to be treated, this suspended substance blocks the matrix network structure of the resin, and therefore it is necessary to remove it in advance.

In order to solve these drawbacks, the granular anion exchange resin can be pulverized into powder to increase its adsorption surface area and react with the treated armpit, which will greatly increase the adsorption rate. Moreover, the utilization rate relative to the theoretical adsorption capacity increased, and it was thought that effective decolorization could be achieved with a small amount of resin.

For the reasons mentioned above, the present inventors conducted intensive studies on the removal of pigment components using powdered anion exchange resins, and as a result, in addition to the above advantages, granular anion exchange resins did not have any advantages. It was discovered that this product newly developed excellent adsorption properties. In other words, it has the ability to specifically adsorb not only low-molecular dyes, but also high-molecular dyes that have absorbance characteristics in the visible high wavelength region of 560 to 720 n+s, and it also has the ability to specifically adsorb to colloidal substances and It has an extremely excellent ability to adsorb and remove suspended matter such as suspended solids, and has an ability that exceeds that of powdered activated carbon. These adsorption properties are not found in existing adsorbents such as powdered activated carbon, granular carbon, bone char, and granular anion exchange resins, and prove the superiority of powdered anion exchange resins.

Based on such knowledge, the applicants of the present application previously proposed in Japanese Patent Application No. 58-47016 a method of decolorizing a liquid by using a powdered anion exchange resin to adsorb a pigment component.

By the way, it is generally said that when a solution is decolorized using an ion exchange resin, not just a powdered anion exchange resin, adsorbed substances such as pigment components contained in the solution accumulate and the activity of the ion exchange resin decreases. A phenomenon occurs. In particular, it is known that in ion exchange resins whose activity has been reduced by the above-mentioned decolorization treatment, the adsorbed substances can hardly be removed even if the resin is washed with a solvent or the like, and the activity does not return to its original state. Therefore, the ion exchange resin used for the above-mentioned decolorization is discarded because it is difficult to reuse it.

However, powdered anion exchange resins are very expensive because the anion exchange resin itself, which is the raw material, is expensive, and running costs increase when they are used as disposable materials. Disposal becomes an issue. In particular, when processing high color value solutions, the resin must be replaced frequently, making the above problem even more pronounced.

Therefore, it is desired to regenerate and use the powdered anion exchange resin, and regarding the regeneration of this powdered anion exchange resin, please refer to B.Christina Goodacre.
etc. are Sugar Industry Technolo
gist Vol 41 (1982) Paper 4
It is only slightly touched in 7+, and hardly seen in other cases.In this report, regeneration is performed using a 10% sodium chloride solution, but since polymer dyes are difficult to desorb, this must be removed in advance. processing, e.g. Talofloc (
Talofloc) treatment is required, which makes the process complicated.

[Problem that the invention seeks to solve]

Therefore, the present invention has been proposed in view of the above-mentioned conventional situation, and it makes it possible to reuse powdered anion exchange resin with a simple operation, and solves problems such as increased running costs and disposal of used resin. An object of the present invention is to provide a method for regenerating a powdered anion exchange resin that can solve the problem.

[Means for solving problems]

The present inventors have attempted and detailed a number of regeneration treatments for powdered anion exchange resins whose activity has been reduced by difficult-to-detach substances such as polymeric dyes and turbid substances by processing high color value liquids rich in turbid substances. As a result of further investigation, new knowledge was discovered and the present invention was completed.

That is, the method for regenerating a powdered anion exchange resin according to the present invention involves purifying a solution containing a pigment component and a turbid substance, and then purifying a powdered anion exchange resin having a particle size of 250p or less, which has adsorbed the adsorbed substance, at a temperature of 40°C or higher. It is characterized by contacting with a 0.1 to 5% acid aqueous solution heated to 4.
It is characterized in that it is brought into contact with a 0.1 to 5% acid aqueous solution heated to 0° C. or higher, and then washed with a 0.1 to 1% alkaline aqueous solution.

As mentioned above, powdered anion exchange resins are known to have excellent adsorption properties, such as the ability to adsorb and remove turbid substances such as colloidal substances and suspended substances, and polymeric dyes. The conventional wisdom regarding granular resin is that
Since these adsorbed substances are trapped inside the matrix network structure of the resin, so-called physically adsorbed, it is said that they are difficult to desorb even if they are treated with chemicals in the regeneration process.

However, the present inventors found that when using an acid aqueous solution heated to 40°C or higher, not only the dye component but also the turbidity, which had been said to be difficult to desorb, was removed from the adsorbed powdered anion exchange resin. It has been found that even pledged objects can be easily attached and detached. What is important here is that the desorption effect is significant only at high temperatures of 40° C. or higher, and that suspended matter is hardly desorbed at room temperature.

Furthermore, at high temperatures above 40°C, even if the acid concentration is low, the desorption effect does not decrease significantly, and if heated above 40°C, even a dilute solution of about 0.1 to 2% can cause polymerization. It was also found that it is possible to desorb pigments and turbid substances.

The fact that even dilute solutions can be used in this way means that
The amount of regenerating agent used is small, and the economic benefits are immeasurable. Furthermore, it goes without saying that in the decolorization process using a granular ion exchange resin, dilute pickling water generated during regeneration can also be used.

Although the details of the above regeneration mechanism are unknown, the adsorption mechanism of polymeric dyes and suspended substances by powdered anion exchange resin is different from the adsorption mechanism by granular anion exchange resin that was previously thought. It is speculated that upon contact with the acid aqueous solution, adsorbed substances such as pigment components and turbid substances undergo morphological changes to a form in which they are more easily desorbed, and this is promoted by increasing the temperature.

By the way, the powdered anion exchange resin that can be recycled according to the present invention is not limited to new powdered anion exchange resins, but also those that have been used multiple times in the decolorization and desalination processes and become unusable and discarded. It is also possible to use a used powdered anion exchange resin such as the one described above, but in this case a phenomenon that was not observed with a new resin was discovered.

That is, when a sugar solution was treated using a powdered anion exchange resin regenerated with an acid aqueous solution, the p of the treated sugar solution was
H was 4 to 5, whereas when treated with new resin, the pH of the treated sugar solution was 7 to 8, indicating a large difference. Furthermore, according to the experiments conducted by the present inventors, the pH of the treated sugar solution
When we investigated the relationship between sugar solution and color value, we found that treated sugar solutions with low pH had a low decolorization rate and significant coloration.

In refined sugar factories, if the pH of the sugar solution is low, subsequent concentration,
Hydrolysis of sugars occurs during the crystallization process, which poses a major problem.

Therefore, we conducted various studies in order to solve the problem of pH decrease especially when using the used powdered strong basic anion exchange resin, and found that after contacting with the acid aqueous solution, a dilute alkaline aqueous solution, for example 0IN (0IN), was used. , 4%) The pH of the treated sugar solution can be adjusted to 8-9 by simply washing with aqueous sodium hydroxide solution.
It was found that the color value was significantly lowered and the reproduction effect was significantly improved.

The reason why the above alkaline washing improves the quality of the treated sugar solution is not yet clear. A strongly basic exchange group that undergoes oxidation to become a weak base.

), so when alkali washing is performed after acid aqueous solution treatment, weakly basic exchange groups with good regeneration efficiency are preferentially converted to OH.
It is thought that the pH of the treated sugar solution increases and the color value decreases because some of the strongly basic exchange groups also become OH-type.

Even if this alkaline cleaning treatment is used after regenerating a new powdered anion exchange resin or a used powdered medium basic or weakly basic anion exchange resin with an acid aqueous solution, the regeneration effect will be improved. The color value of the treated sugar solution also becomes lower.

The acid aqueous solution used in the present invention is usually 0.1 to 5
It is an aqueous solution of about 40% by weight, and needs to be heated to 40°C or higher.

Examples of acids used in the acid aqueous solution include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, and acetic acid, but the use of mineral acids such as hydrochloric acid is more effective.

Most preferably, the low concentration (
For example, 0.1-2%) is brought into contact with an acid aqueous solution, followed by contact with a dilute (for example 0.1-1%) alkaline aqueous solution.

The alkalis used in the above alkaline aqueous solution include:
Sodium hydroxide, potassium hydroxide, lithium hydroxide,
Examples include aqueous ammonia, and salts such as sodium chloride may be added to this alkaline aqueous solution. especially,
Salt containing sodium hydroxide is highly effective. Furthermore, in the decolorization process using a granular ion exchange resin, dilute alkaline wastewater etc. generated during the regeneration operation with alkali can also be used.

The powdered anion exchange resin used in the present invention includes:
Quaternary ammonium groups, alkanol groups, tertiary amine groups, secondary
Strong basic anion exchange resins and medium basic anion exchange resins having ion exchange groups such as strong basic groups such as primary amine groups, primary amine groups, and polyamine groups, medium basic groups, and weak basic groups. , weakly basic anion exchange resins, etc., and their ionic forms include various salt forms such as OH form, CI form, and SO form. CI type strongly basic anion exchange resin is the most effective. On the other hand, since the weakly basic anion exchange resin has excellent desorption properties, it is highly effective for solutions with high color values such as cane sugar solution and beet sugar solution.

The particle size of the powdered anion exchange resin is preferably less than 250 mm, more preferably less than 100 mm. If the particle size is 250p or more, it becomes difficult to remove adsorbed substances, mainly dye components, and it becomes difficult to regenerate. In addition, if the particle size of the powdered anion exchange resin is 5 pL or less, especially 1.5 μL or less, which has a high risk of leakage, it will be difficult to separate, and there is a risk that the resin will be mixed into the processing solution. There is.

Methods for producing the powdered anion exchange resin include a method of pulverizing a granular anion exchange resin and a method of industrial synthesis, but pulverization is generally used. In addition, the pulverization methods include air flow pulverization method, freeze pulverization method,
Mechanical pulverization methods may be used, but it is particularly preferable to use a pneumatic pulverization method or a freeze pulverization method.

The above-mentioned pneumatic pulverization method is a method in which the particulate anion exchange resin, which is a raw material, is self-pulverized into fine particles by vibrations caused by high-frequency pressure fluctuations caused by high-speed vortex flow of air.
It has the characteristic that the time required to powder it to 0 #L or less is extremely short (about several seconds). According to this pulverization method, the temperature rise during pulverization is 40°C or less, so there is no deterioration of the resin due to heat.What is more distinctive is that the powder has excellent desorption properties for pigment components and has a large regeneration effect. An anion exchange resin having a similar shape can be obtained.

In addition, the above-mentioned freeze-pulverization method uses granular anion exchange resin to
For example, the resin is cooled to below -100'C by direct contact with liquid nitrogen, and then the cooled anion exchange resin is immediately pulverized using a hammer mill or the like. In addition to the above-mentioned liquid nitrogen, refrigerants that can be used for the above-mentioned cooling include various low-boiling point liquefied gases such as liquid carbon dioxide, liquid oxygen, and liquefied propane. Preferably, liquid nitrogen is used on the surface.

In this case too, there is no thermal deterioration and the particle size is fine.
Moreover, a powdered anion exchange resin having a relatively uniform particle size can be obtained.

On the other hand, with mechanical grinding methods using ball mills or hammer mills, it is difficult to make the particle size of the ground material uniform.
When using the obtained powdered anion exchange resin, it is preferable to use a sieve or the like to select those with a particle size of 5 to 250.Furthermore, the mechanical pulverization method described above takes a long time to pulverize and causes a rise in temperature. Since it is large, there is a possibility that the decolorizing performance of the powdered anion exchange resin may be reduced.

Anion exchange resins have a relatively low heat resistance temperature. For example, the maximum operating temperature of OH type strongly basic anion exchange resins with quaternary ammonium groups as ion exchange groups is 60°C, and if this temperature is exceeded, Thermal decomposition of the ion exchange groups occurs rapidly. Although the details of the adsorption mechanism of dye components by anion exchange resin are unknown, it is thought that the polarity of the anion exchange resin particle surface is largely involved.
It is undesirable that heat is applied during the grinding.

The powdered anion exchange resin used in the present invention can be used in both a batch method and a column method.

Furthermore, by adopting a multi-stage contact method or a powder resin layer method, the amount used can be significantly reduced, and the processing liquid can be extremely clear.
Very effective.

For example, as shown in Fig. 1, the multi-stage contact system means that a plurality of powder resin columns filled with powdered anion exchange resin, four series in this example, are created, three of which are a three-stage decolorization system, and one The series is like a so-called merry-go-round system in which regeneration towers are used to sequentially perform regeneration operations, and efficient processing is possible.

The powdered resin layer method uses a mixture of powdered anion exchange resin, diatomaceous material, fibrous filter aids (e.g., glass fiber, cellulose fiber, activated carbon fiber, etc.), and adds a precoat layer to a regular filter. This method uses a molded filter plate, or a molded filter plate. According to this powder resin layer method, it is possible to significantly improve pressure drop and hydraulic performance, etc., and the purification operation is significantly easier. Moreover, there is no risk of leakage of the powdered anion exchange resin used. It disappears.

The present invention can be applied to any powdered anion exchange resin used for purifying solutions containing turbid substances such as colloidal substances and suspended substances and pigment components.
In particular, various sugar solutions such as cane sugar solution and beet sugar solution, various plant juices,
It is highly effective when applied to powdered anion exchange resins used for decolorizing and decolloiding pulp factory wastewater, food factory wastewater, etc.

[Effect]

As mentioned above, powdered anion exchange resin whose adsorption capacity has decreased due to the removal of pigment components and turbid substances can be treated with an acid aqueous solution heated to 40°C or
By treating with an acid aqueous solution heated to 0° C. and then washing with an alkaline aqueous solution, the pigment components and suspended matter adsorbed on the powdered anion exchange resin are quickly removed and regenerated.

〔Example〕

The present invention will be explained below with reference to specific examples, but it goes without saying that the present invention is not limited to these examples.

Example 1 Powdered strongly basic anion exchange resin (manufactured by Rohm & φ Haas Co., Ltd., trade name Amberly IRA-401) was crushed to a particle size of 50 hiro or less (average particle size 18.5 g) by air pulverization method. 1 g (dry weight) of powdered anion exchange resin pulverized into a refined intermediate sugar solution (0.15% invert sugar) after the carbonation process at a refined sugar factory.

Bx61. O, pH 8.0, transmittance T2 88.1% 9 Color value index A, I, 750) 300 ml and mixed and stirred at 60°C for 60 minutes to remove pigment components and 11AI! I was adsorbed. After the adsorption was completed, the powdered anion exchange resin was filtered using a membrane filter (Toyo Roshi Co., Ltd. 3L), washed with water, collected, and transferred into a jacketed column.

After keeping the powdered anion exchange resin column adsorbed with this dye component etc. at various temperatures, 200ml of 1% aqueous hydrochloric acid solution was added.
Pass the medicine through, neutralize the regenerated wastewater that flows out to pH 7, and
It was diluted to 0.001.

The absorbance of this waste liquid was measured at 420 to 720 nm, and the dye desorption rate relative to the amount of adsorbed dye at each wavelength was determined. The results are shown in Table 1.

The above dye desorption rate was determined from the following formula.

0.0. ,,: Absorbance of sugar solution to be treated with powder resin 0.0-:
Absorbance of powdered resin-treated sugar solution 0.0: Absorbance of regenerated effluent ■,: Amount of regenerated effluent (■1) ■,: Amount of powdered resin-treated sugar solution (1) W: Dry weight of powdered resin (g) b =Cell length cm) Table 1 From Table 1, it can be seen that when the salt aqueous solution treatment temperature exceeds 40°C, the dye desorption rate is significantly improved over a wide range of 420 to 720 nm.

Example 2 Using 1 g (dry weight) of a powdered strongly basic anion exchange resin prepared in the same manner as in Example 1, a purified intermediate sugar solution was decolorized in the same manner as in Example 1, and then a second Regeneration was performed at a temperature of 60° C. using the regenerant 2001 shown in the table. Table 2 shows the dye desorption rate by each regenerant.

Table 2 From this Table 2, it can be seen that by using an aqueous hydrochloric acid solution or an aqueous solution containing hydrochloric acid, the dye desorption rate in the visible high wavelength region of 560 to 720 nm is significantly increased.

Example 3 A granular strongly basic anion exchange resin (manufactured by Rohm & Haas Co., Ltd., trade name Amberlite I RA-401) was ground in a ball mill to obtain a powdery anion having a particle size distribution as shown in Table 3. Ion exchange resin was prepared by sieving method.

1g of powdered anion exchange resin having each of these particle size distributions
(dry weight), after decolorizing the purified intermediate sugar solution in the same manner as in Example 1, using 200 ml of 1% aqueous hydrochloric acid solution at 60°C.
It was regenerated under the following temperature conditions.

Table 3 shows the dye desorption rate by the regenerant and the decolorization rate and transmittance of the treated sugar solution.

Note that the color value index and decolorization rate were determined from the following formulas.

Xc ” D4%g, 'Test sample (1) pH 7.0 ±
0.1 After adjustment, absorbance b in the 4201 layer = cell length cm) C. Weight of solids in the test sample (g/ml) In addition, the transmittance (turbidity) depends on the pH of the test sample. After adjusting to 7.0±0.1, it was expressed as transmittance (T%) at 720 nm using a 5 cm cell.

From Table 3, it is clear that the particle size distribution is 250 pm or less, especially 21
At 0 μm or less, the decolorization rate and transmittance of the treated sugar solution are good, and the dye desorption rate by regeneration treatment is 420 nm.
It can be seen that it is high over a wide range of ~720r+m.

Example 4: Purification of cane sugar liquid A used granular strongly basic anion exchange resin (manufactured by Mitsubishi Kasei Corporation, trade name FA-308), whose capacity has decreased due to use in the ion exchange resin process, is granulated by an air flow pulverization method. Diameter 50
Used powdered anion exchange resin (strong base exchange capacity 1,000
meq/g, weak base exchange capacity 0.7 meq/g) 2
g (dry weight) and the new powdered anion exchange resin prepared in Example 1 (strong base exchange capacity 0, 7 meq/lot) I
g (dry weight) to decolorize the purified intermediate sugar solution in the same manner as in Example 1, and then add 1% aqueous hydrochloric acid solution to each resin.
001 at a temperature of 60°C. moreover,
If necessary, add 5 l/1 ON sodium hydroxide aqueous solution.
I took 01 medicines.

2. Raw sugar (50% from Thailand, 50% from Cuba, reducing sugar 0.82%) was added to the regenerated powdered anion exchange resin.
%, ash content 0.37%, color index A, 15270) was dissolved in wood, the carbonation method was carried out, and the filtered clear liquid (Bx6
3, pH 7.7, invert sugar 0.71%, permeability T''TI
Dpm79' 3%1 Color value index A, I2380) 30
After mixing and stirring at 60° C. for 60 minutes, the mixture was filtered using a glass fiber filter (GBlooR).

The quality of the treated sugar solution is shown in Table 4.

From Table 4, it can be seen that when NaOH washing is performed, the color value of the treated sugar solution decreases by about 30% for new resin and 45% for used resin, compared to when no treatment is performed.

Example 5 Particulate strongly basic anion exchange resin (IRA-401), particulate weakly basic anion exchange resin (WA-30, manufactured by Mitsubishi Chemical Corporation), and particulate weakly acidic cation exchange resin (WK-11, Mitsubishi Chemical Corporation) Powdered ion exchange resins were prepared by pulverizing each resin (manufactured by Kasei Co., Ltd.) to a particle size of 50p or less using an air flow pulverization method.

Hot liming: Sugar cane imported from Okinawa (approximately 7 days after harvest) is squeezed using a test press, the resulting squeezed juice is heated to 100°C, and then milk of lime is added to adjust the pH to 7.0 to 7.2. After cleaning by method, filter and clear liquid (Bxll, 8
, pH 7.6, Transmittance T"l" 79.7%1 Color value index A
, 117,000 and an apparent pure sugar rate of 84.4).

On the other hand, as shown in Table 5, 1 g of powdered ion exchange resin
(dry weight) mixed with glass fiber and diatomaceous earth and packed into a jacketed column (2c+mφXIOcm),
Further, 41 pieces of granular ion exchange resin (corresponding to 1 g of dry weight) each were filled in the same manner in a wet state.

These resin columns were kept warm at 70°C and the clarified liquid 20
01 was passed at a rate of 301 per hour. After washing with water, 200 ml of 1% aqueous hydrochloric acid solution was passed through to neutralize the regenerated effluent that flowed out to pH 7 and dilute it to 400 ml. Table 5 shows the quality of the treated sugar solution and the dye desorption rate by the regenerant.

In Table 5, the fact that the dye desorption rate in the high wavelength region of 560nIl to 720n11 is more than 100% for the powdered resin means that the soluble non-sugar content in the sugar solution to be treated is adsorbed by the powdered resin. increases, indicating that it is desorbed by the regeneration method according to the present invention.

Example 6゜The used powdered anion exchange resin prepared in Example 4 was suspended in the purified intermediate sugar solution used in Example 1 to make a 1% suspended sugar solution (
10g dry weight/l sugar solution) was prepared.

Furthermore, if necessary, diatomaceous material ± (manufactured by Chuo Silica Co., Ltd., Silica-600H) and glass tal& (manufactured by Fuji Fiberglass Co., Ltd., glass chopped strand cut length 6
2, filament diameter to, 5 g) was added in an amount of 0.2 to 0.5%.

The suspended sugar solution 2501 was mixed and poured into a Millipore filter (filtration area 10 cm, capacity 340 ml) equipped with Toyo Filter Paper No. 2 as a filter medium, and then immersed in a constant temperature bath at 70°C. Constant pressure filtration was performed under pressure of I kg/cm.

Measure the filtration amount and appropriate filtration time, and also check the clear filtrate.
Transmittance at 20 nm was determined. The results are shown in Table ¥p6.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a powdered anion exchange resin whose adsorption capacity has been reduced due to the removal of pigment components and turbid substances is treated with an acid aqueous solution heated to 40°C. Alternatively, it can be easily regenerated by first treating with an acid aqueous solution heated to 40°C and then washing with an alkaline aqueous solution, thus making it possible to use this powdered anion exchange resin repeatedly. , the economic merit is extremely large, and the amount of industrial waste is significantly reduced, which is preferable from the viewpoint of processing labor and pollution.

In particular, used granular anhydride is treated with a low concentration acid aqueous solution (e.g. 061-2% hydrochloric acid solution) heated to 40°C or above, followed by washing with a dilute alkaline aqueous solution (e.g. O, IN sodium hydroxide solution). Used powdered anion exchange resins prepared from ion exchange resins, especially powdered weakly basic anion exchange resins, can be used repeatedly.
Furthermore, the scope of application of powdered anion exchange resins has expanded to include the purification of solutions with high color values, high colloids, and suspended solids, such as cane sugar juice and sugar beet juice, which were previously unapplicable. It is.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a specific configuration of the multi-stage contact method.

Claims (2)

[Claims] (1) A powdered anion exchange resin with a particle size of 250μ or less, which has been purified from a solution containing a pigment component and a suspended substance and has adsorbed the adsorbed substance, is mixed with a 0.1 to 5% acid aqueous solution heated to 40°C or higher. A method for regenerating a powdered anion exchange resin, the method comprising contacting the resin. (2) A powdered anion exchange resin with a particle size of 250μ or less, which has been purified from a solution containing a pigment component and a suspended substance and has adsorbed the adsorbed substance, is mixed with a 0.1 to 5% acid aqueous solution heated to 40°C or higher. A method for regenerating a powdered anion exchange resin, which comprises washing with a 0.1 to 1% alkaline aqueous solution after contacting the resin.