JPS60106540A - Decoloration of solution - Google Patents

Abstract

PURPOSE:To realize econimical decoloration of solution and to improve decoloration efficiency of solution by reusing used particulate anion exchange resin used in another process by recovering and regenerating the resin with a reactivating agent for repeated use. CONSTITUTION:In a process for decolorizing solution by allowing the solution to contact with powdery anion exchange resin, particulate anion exchange resin used in another process is crushed to <=250mu fine particle size which is reactivated by allowing the fine particles to contact with acid (e.g. HCl) and/or metal ion-contg. soln. (e.g. aq. NaCl) to obtain regenerated resin, which is used in this process. The regenerated resin which has been deteriorated again in this process due to adsorption of adsorbate consisting primarily of coloring matters is allowed to contact with acid (e.g. HCl) and/or metal ion-contg. soln. (e.g. aq. NaCl) to regenerate, and regenerated resin is used repeatedly. By this method, economical decoloration of solution is performed, treating efficiency is improved, and decoloration cost is reduced.

Description

[Detailed Description of the Invention] This invention relates to a method for decolorizing a solution colored by a color value,
More specifically, the present invention relates to improvements in decolorizing methods using powdered anion exchange resins.

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.

It is known that an adsorption tower is filled with 3 to 0.6 granular anion exchange resins, and a liquid to be treated is passed through the packed bed to adsorb the 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 processing capacity is low because the adsorption surface area is small and the adsorption speed is slow. (It has the disadvantage that the liquid passing rate cannot be made very high. For this reason, the adsorption tower tends to be relatively large, and the utilization rate with respect to the theoretical adsorption platform amount is also relatively small.

Therefore, it has been considered to utilize a powdered anion exchange resin having a large adsorption surface area for the above-mentioned decolorization. By using this powdered anion exchange resin, the flow rate of the liquid to be treated can be greatly increased, and the utilization rate relative to the theoretical adsorption capacity can also be increased, making it possible to effectively decolorize with a small amount of resin. By the way, if granular anion exchange resin is packed in a packed tower or the like and used for decolorizing various solutions (゛), it may cause a decrease in the through-flow capacity or a decrease in the purity of the treated solution as it is used. occurs, and its ability decreases.

In general, the decrease in the ability of granular anion exchange resins is thought to be due to two factors: a decrease in exchange capacity and a decrease in the intra-particle diffusion rate due to so-called organic contamination, in which organic matter is irreversibly adsorbed on the particle surface. It is known that even if the anion exchange resin is washed with organic substances, it is hardly possible to remove adsorbed substances such as organic substances, and the ability of the anion exchange resin is not equivalent to its original state. Therefore, the granular anion exchange resin is replaced with a new one at some point and discarded as industrial waste. This is thought to be the same for the above-mentioned powdered anion exchange resins, and powdered anion exchange resins with reduced performance are also disposed of.

If the anion exchange resin is made disposable in this way, not only will running costs increase because the anion exchange resin is expensive, but the disposal of the used resin, which is industrial waste, will become a problem. ing.

Particularly when processing high color value solutions, the above-mentioned problem becomes even more pronounced because the above-mentioned resin must be replaced frequently.

As a result of intensive studies in view of the above-mentioned circumstances, the inventors of the present invention have found that used granular anion exchange resin that has been used once in another process is crushed into fine powder, and brought into contact with a certain type of solvent. The inventors have completed the present invention by discovering that the adsorbed substances that could not be desorbed in the granular state can be quickly removed and regenerated as if they were new, and that they can be used repeatedly through regeneration. In order to decolorize the solution by contacting the powdered anion exchange resin, the used granular anion exchange resin used in other processes as the powdered anion exchange resin is pulverized into fine particles of 250 μm or less, and then acid and Alternatively, a powdered anion exchange resin obtained by recycling by contacting with a metal ion-containing solution is used, and a powdered anion exchange resin that has adsorbed the adsorbed substances, mainly pigment components, by the decolorization is acidified. And/or it is characterized by being brought into contact with a metal ion-containing solution to be regenerated and used repeatedly.

Hereinafter, embodiments of the present invention will be described with reference to FIG.

In the present invention, a powdered anion exchange resin 1 is used to decolorize a solution, and in order to produce this powdered anion exchange resin 1, a used granular anion exchange resin 2 is prepared. .

The used granular anion exchange resin 2 may be one that is used in various decolorization processes, desalination processes, etc. and is originally discarded, as described above. In addition, the types include a matrix such as a copolymer of styrene and divinylbenzene or a copolymer of acrylic and divinylbenzene, and a quaternary ammonium group, an alkanol group, a tertiary amine group, a secondary amine group, a primary amine group, etc. Can be used even if it is an anion exchange resin, such as strongly basic anion exchange resins, medium basic anion exchange resins, weak basic anion exchange resins, etc. that have ion exchange groups such as grade amine groups and polyamine groups. In addition to the OH form, its ionic form includes various salt forms such as the CA form and the 804 form, but the CI type strongly basic anionic resin is the most effective. be.

Next, this used granular anion exchange resin 2 is crushed into fine particles in a crushing step 3. The particle size of the fine particles obtained by this pulverization step 3 is preferably 250 μm or less, more preferably 100 μm or less. If the particle size is 250 μm or more, it becomes difficult to remove adsorbed substances, mainly dye components, and regeneration, which will be described later, becomes difficult. In addition, the particle size of the powdered ion exchange resin is 5 μm or less, especially 1.5 μm, which has a high risk of leakage.
If it is less than m, it will be difficult to distinguish, and there is a risk that the resin will be mixed into the decolorizing solution described below.

In addition, examples of the pulverization method include a pneumatic pulverization method, a freeze pulverization method, a mechanical pulverization method, etc., and 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 μm or less is extremely short (about several seconds). With this pulverization method, the temperature rise during pulverization is 40°C or less, so there is no deterioration of the resin due to heat, and the production rate is 99.9 when the effective particle size is 5 to 50 μm.
%. A further characteristic feature is that a powdered anion exchange resin can be obtained which has excellent desorption properties of pigment components and has a large regeneration and regeneration effect.

In addition, the above-mentioned freeze-pulverization method uses granular anion exchange resin to
For example, the anion exchange 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, in the mechanical pulverization method using a ball mill or hammer mill, it is difficult to make the particle size of the pulverized product uniform, and when using the obtained powdered anion exchange resin, it is necessary to use a sieve etc. to It is preferable to select and use them. Furthermore, in the above-mentioned mechanical pulverization method, the time required for pulverization is long and the temperature rise is large, so 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.

Subsequently, the resin made into fine particles in the pulverization step 3 is regenerated in a regeneration step 4. □“As the regeneration agent used in the regeneration step 4, an acid and/or metal ion-containing solution may be mentioned. Acid-containing acetone, acid-containing methanol, and alkali metal ion-containing methanol are particularly effective.Other organic solvents include ethanol,
The use of organic solvents such as ether, chloroform, and hexane also has the effect of desorbing pigment components. Further, examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, etc., but it is more effective to use a mineral acid such as hydrochloric acid. Furthermore, although it is effective to use a saline solution, a saline solution containing 1-lium hydroxide, a saline solution containing hydrochloric acid, etc. as the metal ion-containing solution, the regeneration effect thereof is inferior to that of the acid-containing acetone and the like.

Most preferably, it is first brought into contact with an aqueous solution containing an acid and/or a metal ion, and then brought into contact with a heavy equipment solvent containing an acid and/or a metal ion.

By the way, regarding the acid concentration in the above acid-containing organic solvent,
The higher the concentration, the faster the desorption rate, but even when the concentration was increased to 5% or more, the amount of desorption did not increase significantly. Furthermore, when acid-containing acetone was used, no difference was observed in the desorption performance up to a water content of around 50%.

When the above-mentioned fine particulate anion exchange resin is regenerated using a regenerating agent containing a highly permeable organic solvent such as acetone, the desorption rate is extremely fast, and the adsorption can be achieved with just a short period of contact. It is possible to almost completely remove the pigment components, etc. However, if an aqueous solution is used as the regeneration agent, it is necessary to use a large amount of the regeneration agent and the conditions for use must be at high temperatures. In some cases, the amount of resin used can be significantly reduced, and normally 10 to 10% of the regenerated resin is used.
20 times the amount is sufficient. When using a regeneration agent mainly composed of the above-mentioned organic solvent, the organic solvent used for regeneration can be easily recovered and reused by distillation, etc.
It also has great benefits, such as being able to reduce the amount of waste liquid.

Furthermore, when recovering the organic solvent, there is also the effect of facilitating the recovery of valuable substances in the waste liquid.

Through the above-mentioned regeneration step 4, adsorbed substances accumulated inside the resin pores of the used granular anion exchange resin 2, especially colloidal components containing polymeric dyes and heavy metals, are easily removed.
A powdered anion exchange resin 1 that is as good as new is obtained.

Then, the colored solution 5 to be treated is passed through the powdered anion exchange resin 1 to obtain a decolorized solution 6.

The powdered anion exchange resin 1 has better performance than bone char or granular activated carbon in terms of decolorization, and the solution to be treated 5
The purpose of the era name is achieved with the usage of 0.5 units.

Furthermore, this amount can be significantly reduced by adopting a multi-stage contact method or a powder resin layer method. Therefore, the amount of solution purified per unit amount of resin increases significantly, and in particular, in the powder resin layer method, the amount reaches about 10 times that of the conventional method using a granular anion exchange resin.

In addition, when creating the powdered resin layer, a powdered anion exchange resin, diatomaceous earth, and a fibrous filter aid may be used in combination.

In addition, when the powdered anion exchange resin 1 is used, the liquid to be treated 5 includes color indexes A, I, (Attenua-t
Decolorization can be achieved most effectively when the solution has a high color value of ion Index ) l Q 9 or higher.

Furthermore, the powdered anion exchange resin 1 simply has a larger adsorption amount than the granular anion exchange resin (,5
It was found that the adsorption amount was specifically large for polymer dyes having absorbance characteristics in the visible high wavelength region of 60 to 720 nm.

On the other hand, if the decolorizing ability of the powdered anion exchange resin 1 begins to decline, it is regenerated in a regeneration step 7.

The regenerating agent used in this regeneration step 7 may be the same as the regenerating agent used in the previous regeneration step 4. For example, the powdered anion exchange resin 1 is brought into contact with stirring in a batch method to remove pigment components, etc. The adsorbed substance is desorbed and used again to decolorize the treated object 5.

The present invention can be applied to decolorizing any solution as long as it contains a pigment component that can be adsorbed by the powdered anion exchange resin 1, but in particular various sugar solutions such as cane sugar solution and sugar beet solution. It has a very large regeneration effect and is useful when applied to decolorizing various plant juices, pulp factory waste liquid, food factory waste water, etc.

In particular, when applied to the purification of sugar solutions, the above-mentioned powdered anion exchange resin and powdered cation exchange resin can be used in combination to improve sugar solution that has been treated, for example, in the magnesia cleaning process or carbonate filling process. It can also remove the hardness component of
The purification process can be omitted.

As described above, according to the present invention, used granular anion exchange resin, which should originally be discarded, can be recycled and used like new, and furthermore, it can be recycled with a regenerating agent and used repeatedly. Since the amount of solid industrial waste is significantly reduced, it is favorable from the viewpoint of processing labor and pollution.Furthermore, the decolorizing ability of the powdered anion exchange resin is extremely high. It is also possible to improve processing efficiency and reduce decolorization costs.

Next, specific examples will be described in order to make the present invention more clear, but it goes without saying that the present invention is not limited to these examples.

Example 1 Purification of cane sugar liquid Used granular strongly basic anion exchange resin whose capacity has decreased due to use in the ion exchange resin process is ground in a ball mill to obtain a powder having a particle size distribution as shown in Table 1. Anion exchange resin was prepared by sieving method.

1g of powdered anion exchange resin having each of these particle size distributions
(dry weight) in 10% saline solution containing 1% HC6/5Qm/
It was recycled at a temperature of 70° C. using

The regenerated effluent obtained from this regeneration operation is neutralized to pH 7 and
The absorbance of this waste liquid was measured using a spectrophotometer, and the desorption dye placement in each particle size distribution was compared based on the absorbance. Furthermore, the amount of heavy metals remaining in the powdered anion exchange resin regenerated by the regeneration operation was measured based on the official food additive analysis method. The results are shown in Table 1.

Table 1 As is clear from Table 1, in the state of granular anion exchange resin (particle size of 25.0 μm or more), almost no pigment component was desorbed, whereas in the state of granular anion exchange resin (particle size of 25.0 μm or more), the pigment component was hardly desorbed.
By making the particles smaller than 0.05 μm, the amount of desorbed dye is greatly increased, and the residual heavy metals are also reduced, improving the regeneration effect. In particular, the absorbance at 600 μm was more than 1 (if) times higher, and it was found that it was possible to desorb polymeric dye components that could only be removed with conventional granular anion exchange resins.

Example 2 Purification of cane sugar liquid Used granular strong basic anion exchange resin whose capacity has decreased due to use in the ion exchange resin process is pulverized to a particle size of 50 μm or less (average particle size 18.5 μm) using an air flow pulverization method. Then, 50 m/g of the regenerating agent shown in Table 2 was added to 1 g (dry weight) of the obtained powdered anion exchange resin, and the mixture was brought into contact with the resin for 30 minutes while stirring. Table 2 shows the amount of dye desorbed by each regenerating agent and the amount of heavy metals remaining in the resin.

Note that the regeneration was performed at room temperature when the regeneration agent was based on an organic solvent, and at 70° C. when the regeneration agent was based on an aqueous solution. Further, the amount of the desorbed dye was calculated only for the dye component having absorbance at 420 nm, and the calculation method was according to the following formula.

Table 2 Weight] ``Yoyoyo'' From this Table 2, it can be seen that the desorption effect is excellent in regenerating agents mainly composed of organic solvents, and that 10% Nn containing 1% NaOH, which is an aqueous solution containing acid and/or metal ions, is particularly effective. It is clear that contact with water followed by contact with 80% methanol water containing 5% HCl, an organic solvent containing acids and/or metal ions, can remove the pigment components very effectively.

Example 3 Purification of cane sugar liquid Used granular strong basic anion exchange resin whose capacity has decreased due to use in the ion exchange resin process is pulverized to a particle size of 50 μm or less (average particle size 18.5 μm) using an air flow pulverization method. A powdered anion exchange resin was obtained.

1 g (dry weight) of the obtained powdered anion exchange resin was added to the purified intermediate sugar solution (
BX60. PH8.0, invert sugar 0.16%.

Color values r, b, u, 1237) were added to 200 ml, and the pigment components were adsorbed while stirring at 70° C. for 30 minutes. After the adsorption was completed, the mixture was collected using a 0.8μ membrane filter and transferred to a beer force of 100μ.

The powdered anion exchange resin that has adsorbed this pigment component contains 20%
Add 1 ft/ of acetone and 2 ml of 36% concentrated hydrochloric acid,
Stir for 15 minutes on a madanetic stirrer to regenerate.
The powdered anion exchange resin was filtered using filter paper (No. 2). The same operation was carried out twice, and the regenerated effluents were combined and neutralized with NaOH solution, then diluted to 200 ml, and the absorbance was measured with a spectrophotometer to calculate the dye desorption rate. The above dye desorption rate is determined by the following formula: Color value of regenerated effluent (r, b, u,) x 100 (%) Calculated using the formula.

(However, in the formula, C represents the length of the cell, and C represents the sugar concentration of the sample.) After thoroughly washing the powdered strong basic anion exchange resin after the regeneration operation with water, use it as the liquid to be treated. Using the purified intermediate sugar solution after the completion of the carbonation step, decolorization and purification, collection of powdered anion exchange resin, regeneration, and color purification were repeated.

Although the operation was repeated for 10 cycles, no decrease in decolorizing ability was observed.

Table 3 shows the quality of the treated sugar solution in each cycle and the dye desorption rate in each regeneration operation.

/' / 7・' / /'' / Table 3 Example 4 A granular strongly basic anion exchange resin (trade name Diaion PA308) that has been used for 300 cycles in the desalination process is pulverized by an air flow pulverization method to form a powder. An anion exchange resin (average particle size 23 μm) was obtained.

The obtained powdered anion exchange resin 19 (dry weight) was added to 10 liters of colored wastewater from a food factory, and treated by stirring at room temperature for 20 minutes. After completing the above treatment, the powdered anion exchange resin was filtered through a 10μ membrane filter, and 2007M
It was recovered into the beer force.

To this recovered powdered anion exchange resin, 100 m/80 methanol water and 10 ml of concentrated nitric acid (48%) were added, and ultrasonic stirring was continued for 30 minutes. Subsequently, the powdered anion exchange resin was collected using a 10μ membrane filter, and after washing, the same operation was repeated for three cycles using the colored wastewater described above, but almost no decrease in decolorization ability was observed. The results are shown in Table 4.

Note that ss in Table 14 was measured according to JIS KO1020 method (C).

Table 4

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the steps of a method for decolorizing a solution to which the present invention is applied. Patent applicant: Itochu Sugar Co., Ltd. Representative Patent attorney: Kodo Koike Sakae Taichimura - Part 1-

Claims (1)

[Claims] When the solution is brought into contact with the powdered anion exchange resin to decolorize it, the used granular anion exchange resin used in other processes is used as the powdered anion exchange resin.
A powdered anion exchange resin obtained by grinding into the following fine particles and recovering by contacting with an acid and/or metal ion-containing solution was used, and the adsorbed substances, mainly pigment components, were adsorbed by the decolorization described above. A method for decolorizing a solution, which comprises bringing a powdered anion exchange resin into contact with an acid and/or metal ion-containing solution to regenerate and repeatedly use the resin.