JP5711510B2 - Acrylic resin for adsorbent, water treatment column, and water treatment method - Google Patents

Description

Embodiments described herein relate generally to an adsorbent acrylic resin, a water treatment column, and a water treatment method.

Water such as industrial wastewater, groundwater, and seawater contains various ions. Effective use of resources has become an important issue due to population growth and industrial development in recent years. Therefore, water treatment technology that separates water and ions and recovers water resources is very important. Various methods are known as a method for separating other substances from a liquid, and examples thereof include solid-liquid separation by aggregation, centrifugation, membrane separation, activated carbon adsorption, and ozone treatment. By using such a method, it is possible to remove chemical substances having a great influence on the environment such as phosphorus and nitrogen contained in water, and oils and clay dispersed in water.

As methods for removing ions dissolved in water, membrane separation, electrical separation, ion exchange, coagulation precipitation, and the like are known. Of these, the most common method for removing borate ions is ion exchange. For example, as an acrylic resin of borate ion, a glucamine type is known.

When water treatment is performed using ion exchange, water is passed through a column filled with an acrylic resin to adsorb target ions to the acrylic resin. Thereafter, the acrylic resin is regenerated by passing acid and base through the column. By increasing the adsorption amount of the acrylic resin, the running cost can be reduced. In addition, a large amount of ions can be processed at a time. In addition, the development of acrylic resins that can handle various types of wastewater is desired.

JP 2003-64128 A

The problem to be solved by the present invention is to provide an adsorbent acrylic resin, a water treatment column, and a water treatment method with a large amount of adsorption.

The acrylic resin for adsorbents according to one embodiment of the present invention has a structural unit represented by the formula (1).
(R ¹ is hydrogen or a methyl group, R ² is an alkyl group having two or more primary hydroxyl groups, and n is an integer of 3 to 1,000,000.)

It is a figure which shows schematic structure of the apparatus used for the water treatment which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail.
The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between the parts, and the like are not necessarily the same as actual ones.

(First embodiment)
The adsorbent is used by being packed in a column. When water containing target ions to be adsorbed is introduced from the column inlet, the target ions are adsorbed by the adsorbent, and water from which the target ions have been removed comes out from the column outlet.

Below, an acrylic resin particle is demonstrated. The acrylic resin particles can generate various adsorbents through a chemical reaction. Therefore, an adsorbent having a substituent that adsorbs the target ions can be obtained. The acrylic resin particles themselves can also be used as an adsorbent that adsorbs borate ions, for example.

The acrylic resin in this embodiment is, for example, in the form of particles, and each particle is composed of an acrylic resin having a structural unit represented by the formula (1).

Here, R ¹ represents hydrogen or a methyl group. R ² is a branched alkyl chain having at least two primary hydroxyl groups with respect to the alkyl chain. The alkyl chain may have a cyclic structure. Further, this alkyl chain may be partially substituted or unsubstituted.
n is an integer of 3 to 1 million. That is, one molecule of the acrylic resin has n structural units represented by the formula (1).

That is, the structural unit of the acrylic resin has a structure in which an ester structure of an acrylate ester is converted to an amide structure, and a primary polyvalent hydroxyl group is bonded to the N atom of the amide structure via an alkyl chain. An example of the structure is one in which trishydroxymethylaminomethane is introduced. When trishydroxymethylaminomethane is introduced, the formula (1) can be expressed as the formula (2).

Here, R ¹ represents hydrogen or a methyl group. n is an integer of 3 to 1 million. That is, one molecule of the acrylic resin has n structural units represented by the formula (2).

In a state where the acrylic resin is not immersed in water, the acrylic resin becomes gel or porous due to a manufacturing method described later. The gel state in this case refers to a state in which the resin is three-dimensionally crosslinked and no continuous pores are opened. The term “porous” refers to a state in which one independent hole is formed inside the three-dimensional structure of the resin, or a plurality of holes are continuously formed.

The acrylic resin takes in the target ions to be adsorbed into the three-dimensional structure. When ions that easily bind to a hydroxyl group are taken into the interior of the three-dimensional structure, they are adsorbed. Thus, the above-mentioned acrylic resin can be used as an adsorbent. Since the alkyl chain of R ² has a branch,
The more branches to which a hydroxyl group is bonded, the more ions are adsorbed.

Moreover, since the adsorbent obtained by chemically reacting the acrylic resin also has a three-dimensional structure derived from the above-mentioned acrylic resin, ions can be taken in and adsorbed therein.

The reason why the hydroxyl group in the structure of the formula (1) is primary is that it has higher reactivity than secondary and tertiary hydroxyl groups. This is because the substituents around the hydroxyl group become bulky as it becomes secondary and tertiary.

Unlike the ester structure, the acrylic resin represented by the formula (1) is resistant to acids and alkalis and has excellent chemical resistance.

Moreover, since the acrylic resin represented by the formula (1) has an amide structure in the structure, it has high hydrophilicity and water easily diffuses into the inside of the particles. Therefore, the water treatment speed can be increased.

Since the acrylic resin represented by the formula (1) can be manufactured without including a water-inhibiting reaction that is difficult to control in the manufacturing process, the acrylic resin can be easily manufactured with fewer processes.

In addition, n which shows a polymerization degree is the range of 10 or more, Preferably it is 100 or more, More preferably, it is 10,000 or more. When n is less than 10, the molecular weight is too small and the softening point becomes low, and it cannot exist as a particulate solid at room temperature. If it cannot exist in the form of particles, the above-described effects cannot be achieved.

On the other hand, when n exceeds 1,000,000, the molecular weight of the acrylate resin used for producing the acrylic resin represented by the formula (1) becomes too large, and the reactivity of the acrylate resin decreases. The acrylic resin represented by the formula (1) is obtained by reacting an acrylic ester resin with a reagent and adding a functional group that adsorbs a target ion. When the acrylic ester resin represented by the formula (1) becomes difficult to react with the reagent, the number of functional groups contained in the resulting acrylic resin is reduced. Accordingly, the adsorption action of the acrylic resin represented by the formula (1) is reduced.

The molecular weight of the acrylic resin represented by the formula (1) is preferably 10,000 or more, more preferably 200,000 or more in terms of polystyrene-converted average molecular weight. When the molecular weight is less than 10,000, when adding a hydrophilic functional group, there is a risk of softening when immersed in water. Softened resin particles may be difficult to use. The upper limit of the molecular weight is not particularly limited, but preferably 3 million or less. As the molecular weight increases, the reactivity decreases, and the adsorption action of the acrylic resin may decrease.

The polystyrene conversion molecular weight is measured by dissolving the above acrylic resin in tetrahydrofuran, measuring the retention time by GPC (gel permeation chromatography), and comparing the polystyrene with standard molecular weight controlled polystyrene. Is calculated.

Moreover, it is preferable that the average particle diameter of acrylic resin represented by Formula (1) is in the range of 100 μm to 5000 μm. As a result, in the water treatment, it is possible to achieve both a high filling rate of the column and ease of water flow. The average particle diameter can be measured by a laser diffraction method. Specifically, it can be measured by a SALD-DS21 type measuring device manufactured by Shimadzu Corporation.

The bulk density of the acrylic resin represented by the formula (1) is 0.2 g / cm ^{3 to} 1.0 g / cm ^3.
It is preferable that it is the range of these. The bulk density can be measured by putting powder from a certain height into a container having a certain volume, filling the container, and measuring its weight. Here, particles produced from above are dropped into a 1 ml scale in a 10 ml graduated cylinder, and the bulk density is determined by measuring its mass. In particular, when the acrylic resin is a porous body, the bulk density is 0.2.
If it is smaller than g / cm ³ , the proportion of pores is too large, and it becomes difficult to maintain the strength of the particles.
It is theoretically difficult to set the bulk density to 1.0 g / cm ³ or more.

Using an acrylic resin represented by the formula (1) as a raw material, an epoxy group is introduced into the primary hydroxyl group,
Furthermore, it is possible to produce an adsorbent by introducing a substituent having high affinity for ions into the epoxy group.

That is, it is also possible to introduce a branched primary hydroxyl group into the amide structure via an alkyl chain, introduce an epoxy group into the hydroxyl group, and add a substituent having high affinity for ions to the epoxy group. That is. An acrylic resin into which an epoxy group has been introduced can be represented by the formula (3) from the acrylic resin represented by the formula (1).

Here, R ¹ represents hydrogen or a methyl group. R ³ is a branched alkyl chain, and R ⁴ , R ⁵
Is an epoxy group containing an alkyl chain. Each alkyl chain may have a cyclic structure. Further, this alkyl chain may be partially substituted or unsubstituted. n
Is an integer from 3 to 1 million. That is, one molecule of the acrylic resin has n structural units represented by the formula (3).

An acrylic resin in which a substituent having a high affinity for ions is introduced into the epoxy group can be represented by the formula (4).

Here, R ¹ represents hydrogen or a methyl group. R ³ is a branched alkyl chain, and R ⁶ , R ⁸
Is a substituent having high affinity for an ion containing an alkyl chain, and R ⁷ is an alkyl group having a structure in which an epoxy group is opened. Each alkyl chain may have a cyclic structure. Further, this alkyl chain may be partially substituted or unsubstituted. n is an integer of 3 to 1 million. That is, one molecule of the acrylic resin has n structural units represented by the formula (4).

The substituent having high affinity for ions is included in R ⁶ and R ⁸ , and examples thereof include polyol, iminodiacetic acid, polyamine, sulfo group, carboxyl group, and amino group.

A resin obtained by performing such a reaction can be used as an adsorbent. When a substituent having a high affinity for ions is introduced at the end of each branch of the branched chain structure, a large amount of ions can be adsorbed.

For example, the acrylic resin represented by the formula (4) having an amino polyol group introduced can adsorb metalloid ions including borate ions. One specific example of this amino polyol is N-methylglucamine. When trishydroxymethylaminomethane is used as the branched chain structure and N-methylglucamine is used as the aminopolyol, the acrylic resin of the formula (4) is represented by the formula (5).

Here, R ¹ represents hydrogen or a methyl group. R ⁹ is an alkyl chain having a structure in which an epoxy group is opened, and R ¹⁰ is N-methylglucamine. R ¹¹ and R ¹² are hydrogen, an epoxy group, or N-methylglucamine introduced at the end of an alkyl chain having an epoxy group opened. Each alkyl chain may have a cyclic structure. Further, this alkyl chain may be partially substituted or unsubstituted. n is an integer of 3 to 1 million. That is,
One molecule of the acrylic resin has n structural units represented by the formula (5).

(Second Embodiment)
An example of the method for producing an acrylic resin represented by the formula (1) and the method for producing an adsorbent obtained using the acrylic resin represented by the formula (1) as a raw material will be described below. That is, the ester bond site of the acrylic ester resin is changed to an amide structure, a primary hydroxyl group is bonded to the N atom of the amide structure via an alkyl chain, an epoxy group is introduced into this hydroxyl group, and further to this epoxy group Introduce a substituent with high affinity for ions. Details of each reaction will be described below.

  First, a method for obtaining an acrylic ester resin will be described.

The acrylic ester resin can be obtained by using a general synthesis method such as suspension polymerization, emulsion polymerization, bulk polymerization, solution polymerization, soap-free polymerization, precipitation polymerization or the like.

Examples of acrylic ester monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate,
Alkyl (meth) acrylates such as lauryl (meth) acrylate and stearyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, etc. Non-crosslinkable (meth) acrylic acid ester monomers. Among these, it is particularly preferable to use a (meth) acrylic acid ester monomer.

On the other hand, the acrylic ester resin obtained as described above can be cross-linked using a cross-linking agent containing an olefin when the molecular weight is increased to, for example, 10,000 or more, particularly 200,000 or more.

Examples of such cross-linking agents containing olefins include polyvinyl monomers that can be cross-linked according to the intended polymer particles, such as divinylbenzene, divinylnaphthalene, divinyltoluene, divinylxylene, trivinylbenzene, 1,3. , 5-triacryloylhexahydro-1,3,5-triazine and other aromatic polyvinyl monomers, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, butylene glycol diacrylate, butylene dimethacrylate Examples include aliphatic polyvinyl monomers such as glycol esters.
You may use these in mixture of 2 or more types. Among these, aromatic polyvinyl monomers,
In particular, it is preferable to use divinylbenzene.

When an aromatic polyvinyl monomer is used as a crosslinking agent, a structure in which an ester structure of an acrylic ester resin is converted to an amide structure and a primary polyvalent hydroxyl group bonded to an N atom of the amide structure via an alkyl chain is introduced The unit can also be expressed as in equation (6) instead of equation (1).

Here, R ¹ represents hydrogen or a methyl group. R ² is an alkyl chain having a straight chain structure, a branched structure, or both, and indicates that the alkyl chain has at least two primary hydroxyl groups. The alkyl chain may have a cyclic structure. Moreover, this alkyl group may be partially substituted or may not be substituted. l, m, and n are integers of 3 to 1 million.

The amount of the olefin-containing cross-linking agent used can be arbitrarily added depending on the properties of the acrylate resin, and is not particularly limited.
It can be 5-90 mass%.

In addition, when the above-described monomer is polymerized, a polymerization initiator can be appropriately used. As such a polymerization initiator, for example, a known oil-soluble radical generator is used, such as a peroxide catalyst such as benzoyl peroxide, lauroyl peroxide, tertiary butylhydroxyperoxide, or azobisisobutyronitrile. And azo polymerization initiators. The amount of the polymerization initiator used is usually 500 to 30,000 ppm, preferably 50, based on the monomer component.
0 to 10,000 ppm.

Furthermore, you may use a dispersion stabilizer with respect to the monomer mentioned above. As a dispersion stabilizer,
Examples thereof include water-soluble polymer compounds such as carboxymethyl cellulose, polyvinyl alcohol, gelatin, and starch. Usually, the amount of the dispersion stabilizer used is preferably 0.001% by mass to 1% by mass with respect to the monomer layer, and more preferably 0.01% by mass to 0.1% by mass.

In addition, as a material for making the acrylic ester resin particles porous, an organic solvent that is soluble in the monomer and the crosslinking agent and insoluble in the polymer and the dispersion medium can be added to the reaction system. Since the surface area where the adsorbent comes into contact with water can be increased by increasing the porosity, the amount of the adsorbent adsorbing target ions can be increased.

Examples of porous materials include benzene, toluene, xylene, chlorobenzene,
Organic solvents such as heptane, isooctane, 2-ethylhexanol, tert-amyl alcohol, decanol, methyl isobutyl ketone, diisobutyl ketone and the like can be mentioned. You may use these in mixture of 2 or more types. Usually, the amount of the porous agent used is preferably 300% by mass or less, more preferably 250% by mass or less, based on the weight of all monomers and the crosslinking agent.

Next, a method for obtaining an acrylic resin represented by the formula (1) from an acrylic ester resin will be described.

The acrylic resin represented by the formula (1) can be obtained by reacting an acrylic resin with a reagent having a structure in which a primary hydroxyl group is bonded to an amino group via an alkyl chain.
This reaction can be carried out in the presence of any base and solvent. Examples of the reagent include trishydroxymethylaminomethane, 2-amino-1,3-propanediol, 2-amino-2-
Examples include methyl-1,3-propanediol and 2-amino-2-ethyl-1,3-propanediol. Of these, it is particularly desirable to use trishydroxymethylaminomethane.

Next, a method for introducing an epoxy group into the acrylic resin represented by the formula (1) will be described.

As this method, a method of reacting a reagent having an epoxy group with an acrylic resin into which the primary hydroxyl group has been introduced can be mentioned. Moreover, after reacting the reagent which has an allyl group, and the acrylic resin which introduce | transduced the said primary hydroxyl group, the method of oxidizing a reaction material using arbitrary oxidizing agents, etc. are mentioned.

Reagents that have an epoxy group include epichlorohydrin, epibromohydrin,
Examples include ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin diglycidyl ether, polypropylene glycol diglycidyl ether, 4-chloro-1,2-epoxybutane, 4-bromo-1,2-epoxybutane. Examples of the reagent possessed include allyl chloride, allyl bromide, 4-bromo-1-butene, and 4-chloro-1-butene.

Subsequently, a method for obtaining an acrylic resin into which a substituent having a high affinity for ions is introduced from an acrylic resin into which an epoxy group has been introduced will be described.

Epoxy groups are highly reactive, and can react with various functional groups by opening the epoxy group. Therefore, various adsorbents are generated by reacting a compound having a first functional group that reacts with an epoxy group and a second functional group that has adsorptivity (reactivity) with respect to ions with the epoxy group. be able to.

The compound becomes bonded to the resin through a reaction between the epoxy group of the resin and the first functional group of the compound. As a result, it is possible to provide an adsorbent containing a second functional group having adsorptivity to a predetermined substance. In other words, it is possible to provide various adsorbents by simply modifying the acrylic resin having an epoxy group. Examples of the first functional group that reacts with the epoxy group include a hydroxyl group, an amino group, a carboxyl group, and a thiol group. As the second substituent, polyol, iminodiacetic acid,
A polyamine, a sulfo group, a carboxyl group, an amino group, etc. are mentioned. The second functional group may not be included in the compound from the beginning, and may be a functional group that is generated as a result of the reaction between the epoxy group and the first functional group.

When the borate ion is the target ion, the second functional group includes a polyol structure. Polyol has a high affinity not only for borate ions but also for semi-metal ions such as selenium, arsenic, tellurium and germanium.

For example, N-methylglucamine has a secondary amino group and a hydroxyl group in the structure. This secondary amino group serves as the first substituent and the hydroxyl group as the second substituent. Both of these substituents react with the epoxy group, but the secondary amino group reacts faster, so this amino group is the first.
Reacts with an epoxy group as a functional group. As a result, a polyvalent hydroxyl group is generated as the second functional group. This polyvalent hydroxyl group is bonded to and adsorbed with borate ions in water, and borate ions can be removed from water.

The adsorbent thus obtained has an ester structure of an acrylate ester converted to an amide structure, a primary polyvalent hydroxyl group bonded to the N atom of the amide structure via an alkyl chain, and an epoxy group attached to the hydroxyl group. And an acrylic resin having a second substituent such as a polyol, iminodiacetic acid, polyamine, sulfo group, carboxyl group or amino group in the epoxy group.

The degree of polymerization of the acrylic resin particles of the adsorbent is from 10 to 1,000,000. The molecular weight of the adsorbent is preferably 10,000 or more, more preferably 200,000 or more in terms of polystyrene-converted average molecular weight. The average particle size of the adsorbent is preferably in the range of 100 μm to 5000 μm. Further, it is preferable that the bulk density of the adsorbent is in the range of ^{0.2g / cm 3 ~1.0g / cm 3} .

Note that the chemical formulas of the various types of acrylic resin particles described above can be known by using the KBR method in infrared spectroscopy (IR) or using solid nuclear magnetic resonance (solid NMR).

(Third embodiment)
As a compound having the first and second functional groups described in the second embodiment, when a substituent having a high affinity for heavy metals is introduced into the second functional groups, an adsorbent for treating heavy metals can be provided. become able to.

Examples of the second substituent include iminodiacetic acid and polyamine. Iminodiacetic acid,
Polyamines can adsorb heavy metal ions such as copper, zinc, cadmium and nickel. In addition, various ions can be adsorbed by introducing a chelate structure other than the above, or a substituent having a sulfo group, a carboxyl group, or an amino group as the second substituent. The second functional group may not be included in the compound from the beginning, and may be a functional group that is generated as a result of the reaction between the epoxy group and the first functional group.

Since the acrylic resin is also an acrylic resin containing an amide structure, it is resistant to acids and alkalis, and since it has an amide bond structure, it has high hydrophilicity, so that the water treatment speed can be increased.
Further, since it can be produced without including a water-inhibiting reaction that is difficult to control in the production process, it can be produced easily with fewer steps.

(Fourth embodiment)
A method for purifying water by adsorbing target ions using an acrylic resin will be described below. Here, the target ions will be described as borate ions. First, an apparatus used for the adsorption operation will be described.

FIG. 1 is a diagram showing a schematic configuration of an apparatus used for borate ion adsorption in the present embodiment. As shown in FIG. 1, in this apparatus, the adsorption means T1 and T2 filled with the borate ion acrylic resin described above are arranged in parallel, and contact efficiency is promoted outside the adsorption means T1 and T2. Means X1 and X2 are provided. The contact efficiency promoting means X1 and X2 can be a mechanical stirrer or a non-contact magnetic stirrer, but they are not essential components and may be omitted.

Further, the adsorption means T1 and T2 are provided with a to-be-treated medium storage tank W1 in which a to-be-treated medium containing borate ions is stored through supply lines L1, L2 and L4, and discharge lines L3 and L5. And L6. Further, the suction means T1 and T2
Is connected to a desorption medium storage tank D1 in which a desorption medium is stored via supply lines L11, L12, and L14, and a desorption medium recovery tank R1 via discharge lines L13, L15, and L16. Is connected.

The adsorbing means T1 and T2 each include a column filled with a borate ion acrylic resin as described above, for example, a borate ion acrylic resin having a structural unit represented by the formula (1).

The supply lines L1, L2, L4, L12 and L14 have valves V1, V, respectively.
2, V4, V12 and V14 are provided, and the discharge lines L3, L5, L13 and L15 are provided.
And L16 are provided with valves V3, V5, V13, V15 and V16, respectively. The supply lines L1 and L11 are provided with pumps P1 and P2. Further, concentration measuring means M1, M2, and M3 are provided in the medium to be treated storage tank W1, the supply line L1, and the discharge line L6, respectively, and the desorption medium storage tank D1, the discharge line L16, and the desorption medium recovery tank R1 are provided. Are provided with concentration measuring means M11, M12 and M13, respectively.

In addition, monitoring of measured values in the above-described valve and pump control and measurement device is as follows.
Centralized management is performed by the control means C1.

  Next, boric acid ion adsorption operation using the apparatus shown in FIG. 1 will be described.

First, the medium to be treated is supplied from the tank W1 to the suction means T1 and T2 through the supply lines L1, L2, and L4 to the suction means T1 and T2. At this time,
The borate ions in the medium to be treated are adsorbed by adsorption means T1 and T2 (borate ion acrylic resin packed in the column), and the medium to be treated after adsorption is the discharge lines L3 and L5.
And discharged through L6.

At this time, the contact efficiency promoting means X1 and X2 are driven as necessary, and the adsorption means T1 and T2 are driven.
The contact area between the boric acid ion acrylic resin filled in the medium 2 and the medium to be treated can be increased, and the adsorption efficiency of boric acid ions by the adsorption means T1 and T2 can be improved.

Here, the adsorption states of the adsorption means T1 and T2 are observed by the concentration measurement means M2 provided on the supply side and the concentration measurement means M3 provided on the discharge side of the adsorption means T1 and T2. When the adsorption is performed smoothly, the borate ion concentration measured by the concentration measuring means M3 is lower than the borate ion concentration measured by the concentration measuring means M2. However, the adsorption means T1
As the adsorption of borate ions at T2 and T2 progresses gradually, the concentration difference between the borate ions at the concentration measuring means M2 and M3 arranged on the supply side and the discharge side decreases.

Therefore, the concentration measuring means M3 reaches a predetermined value set in advance, and the adsorption means T1 and T2
When it is determined that the boric acid ion adsorption capacity by water reaches saturation, the concentration measuring means M2, M3
Based on the information from the control unit C1, the control unit C1 temporarily stops the pump P1, closes the valves V2 and V4, and stops the supply of the processing medium to the suction units T1 and T2.

Although not shown in FIG. 1, the pH of the medium to be treated fluctuates or p
When H is strongly acidic or strongly basic and is out of the pH range suitable for the acrylic resin according to the present embodiment, the concentration measurement means M1 and / or M2 causes the p of the medium to be treated.
H may be measured and the pH of the medium to be treated may be adjusted through the control means C1.

After the adsorption means T1 and T2 reach saturation, the desorption medium is supplied from the desorption medium storage tank D1 to the adsorption means T1 and T2 through the supply lines L11, L12, and L14 by the pump P2. The borate ions adsorbed on the adsorbing means T2 are eluted (desorbed) into the desorption medium, discharged to the outside of the adsorbing means T1 and T2 through the discharge lines L13, L15, and L16, and recovered in the recovery tank R1. Is done. In addition, it can also be made to discharge | emit outside, without collect | recovering to collection tank R1. Alternatively, the borate ions may be separated by filtration and recovered.

When borate ions are smoothly desorbed from the adsorption means T1 and T2 by the desorption medium, the concentration of borate ions measured by the concentration measurement means M12 provided on the discharge side of the desorption medium. Indicates a higher value than the concentration measuring means M11 provided on the supply side. However,
As the desorption of borate ions in the adsorbing means T1 and T2 progresses gradually, the difference in concentration of the borate ions in the concentration measuring means M11 and M12 arranged on the supply side and the discharge side decreases.

Therefore, when the concentration measuring means M12 reaches a predetermined value set in advance and it is determined that the boric acid ion desorption ability by the adsorption means T1 and T2 by the desorption medium has reached saturation, the concentration measuring means M11, Based on the information from M12, the control means C1 temporarily stops the pump P2, closes the valves V12 and V14, and stops the supply of the processing medium to the suction means T1 and T2.

After the desorption of borate ions from the adsorption means T1 and T2 is completed as described above,
The medium to be treated can be supplied again from the medium to be treated tank W1, and borate ions can be adsorbed to reduce borate ions in the medium to be treated.

The concentration measuring means M13 is configured to appropriately measure the concentration of borate ions in the desorption medium recovery tank R1 as necessary.

In the above example, boric acid ions are simultaneously adsorbed and desorbed by the adsorbing means T1 and T2, but these operations are alternately performed by the adsorbing means T1 and T2. You can also. For example, boric acid ions are first adsorbed by the adsorbing means T1, and after the adsorbing capacity reaches saturation, the boric acid ions are desorbed as described above from the adsorbing means T1 and at the same time by the adsorbing means T2. It is also possible to adsorb borate ions.

In this case, in the apparatus shown in FIG. 1, boric acid ions can always be adsorbed in either the adsorbing means T1 or T2, so that continuous operation is possible.

As the desorption medium, an acidic solvent such as dilute hydrochloric acid aqueous solution or dilute sulfuric acid aqueous solution having a pH of about 1 to 5 can be used. The amount of the desorption solvent is 2 of the volume of the adsorption means T1 and T2.
It is preferable that they are 10 times or more. If it is less than 2 times, the borate ion may not be desorbed sufficiently efficiently. If it is more than 10 times, the cost of the drug is increased, which is inefficient.

  Next, specific examples will be described.

(Example 1)
The synthesis of the adsorbent will be described.

As the oil layer, 7.8 ml of methyl acrylate, 4.9 ml of 55% divinylbenzene, 17 ml of monochlorobenzene, and 0.1 g of azobisisobutyronitrile were used.
l, 9.8 g of sodium chloride and 0.04 g of polyvinyl alcohol,
6 hours at 0 ° C. Thereby, an acrylic resin of spherical particles having an average particle diameter of 400 μm was obtained. 1.50 g of this acrylic resin and 2.85 g of trishydroxymethylaminomethane
And 3.47 g of potassium carbonate were stirred in 18 ml of dimethyl sulfoxide at room temperature for 24 hours. After completion of the reaction, the mixture was filtered, washed with water and acetone, and then dried to obtain an acrylic resin.

1 g of acrylic resin obtained by drying and 5.64 g of allyl bromide were put into 18.4 ml of 10 wt% NaOH aqueous solution and reacted at 60 ° C. for 24 hours. After the reaction, the mixture is filtered, washed thoroughly with water and acetone and then dried. Further, 7.5 g of metachloroperbenzoic acid is added to 1 g.
. The mixture was added to 10 ml of 2-dichloroethane and stirred at 25 ° C. for 24 hours. After the reaction, it was filtered and sufficiently washed with water to obtain acrylic resin particles. Acrylic resin particles obtained by washing
5 g and 1 g of N-methylglucamine were put into 10 ml of methanol and reacted at 60 ° C. for 3 hours. After the reaction, it was washed with water and methanol and dried to obtain an adsorbent.

This adsorbent is an acrylic resin represented by the formula (4), and R ⁸ is N-methylglucamine.

(Example 2)
A series of syntheses were performed in the same manner except that N-methylglucamine in Example 2 was changed to trishydroxymethylaminomethane.

That is, the adsorbent obtained is an acrylic resin particle represented by the formula (4) in which the N-methylglucamine moiety is trishydroxymethylaminomethane.

( Reference Example 3)
As the oil layer, 9.3 ml of methyl acrylate, 2.0 ml of 55% divinylbenzene, 17 ml of monochlorobenzene, and 0.1 g of azobisisobutyronitrile, and 250 ml of water, 9.8 g of sodium chloride, and 0.04 g of polyvinyl alcohol as the water layer. The suspension polymerization was carried out at 80 ° C. for 6 hours. Thereby, an acrylic resin of spherical particles having an average particle diameter of 400 μm was obtained. 2.00 g of this acrylic resin, 3.80 g of trishydroxymethylaminomethane and 4.63 g of potassium carbonate were stirred in 24 ml of dimethyl sulfoxide at room temperature for 24 hours. After completion of the reaction, the mixture was filtered, washed with water and acetone, and then dried to obtain an adsorbent. This adsorbent is represented by the formula (2).

(Comparative Example 1)
1.5 g of the spherical acrylic resin obtained by suspension polymerization as in Example 1 was added to ethylenediamine 2
Stirring was performed in 0 ml at 100 ° C. for 12 hours. After completion of the reaction, the mixture was filtered, washed with water and acetone, and then dried to obtain an adsorbent. The subsequent epoxidation reaction and the reaction for introducing N-methylglucamine were carried out in the same manner as in Example 1.

(Comparative Example 2)
As in Example 1, 1.5 g of spherical acrylic resin obtained by suspension polymerization, 1.44 g of monoethanolamine and 3.47 g of potassium carbonate were stirred in 18 ml of dimethyl sulfoxide at room temperature for 24 hours. After completion of the reaction, the mixture was filtered, washed with water and acetone, and then dried to obtain an adsorbent. The subsequent epoxidation reaction and the reaction for introducing N-methylglucamine were also synthesized in the same manner as in Example 1.

(Comparative Example 3)
About 1.5 g of spherical acrylic resin obtained by turbid polymerization as in Reference Example 3, ethylenediamine introduction, epoxidation, and N-methylglucamine introduction were performed under the conditions of Comparative Example 1.

[Adsorption test]
Using the adsorbent obtained as described above, an adsorption performance test for borate ions was performed.

Borax decahydrate dihydrate _{(Na 2 B 4 O 7 ·} 10H 2 O) 4410mg, calcium sulfate (Ca
SO4 · 2H2O) 2577 mg, sodium chloride (NaCl) 2460 mg 1000
The test solution was prepared by dissolving in ml of pure water to a concentration of 500 ppm B. 10 ml of this solution
250 mg of each of the adsorbents of Examples 1 and 2 and Comparative Examples 1 and 2 was added, and the mixture was stirred at a rotational speed of 16 rpm with a mixer. The boric acid ion concentration after 1 hour is measured with an ICP emission spectrometer, and the boric acid ion adsorption amount per unit mass of the adsorbent from the residual boric acid ion concentration (unit: mg-B / g) Was calculated.

Example 4
Using the adsorbent prepared in Example 1, an adsorption performance test for germanium was performed.

1 by dissolving germanium dioxide in aqueous sodium hydroxide solution and neutralizing with hydrochloric acid
A test solution having a concentration of 0 ppm Ge was prepared. 10 ml of the adsorbent of Example 1 was added to 50 ml of this solution.
0 mg was added and stirred at a rotational speed of 16 rpm with a mixer. The germanium concentration of the specific treated water after 6 hours was measured with an ICP emission analyzer, and the residual germanium concentration was measured and found to be 0.8 ppm or less.

(Example 5)
0.5 g of the acrylic resin treated with metachloroperbenzoic acid of Example 1 was stirred at 100 ° C. for 6 hours in 10 ml of diethylenetriamine. After completion of the reaction, the mixture was filtered, washed with water and acetone, and then dried to obtain an adsorbent. This adsorbent is acrylic resin particles represented by the formula (2), and R ⁸ is polyethylene diethylenetriamine.

An adsorption performance test for nickel was conducted using this adsorbent. That is, nickel chloride was dissolved in pure water to prepare a test solution having a concentration of 10 ppm Ni. 100 mg of the adsorbent modified with diethylenetriamine was added to 50 ml of this solution, and the rotation speed was 16 r with a mixer.
Stir to pm and stir. The nickel concentration of the specific treated water after 6 hours was measured with an ICP emission analyzer, and the residual nickel concentration was measured and found to be 1.0 ppm or less.

Table 1 shows the results of the adsorption test for borate ions in Examples 1 to 2, Reference Example 3 and Comparative Examples 1 to 3, the adsorption test for germanium in Example 4, and the adsorption test for nickel in Example 5. Shown in

As is clear from Table 1, the adsorbents of Examples 1 and 2 and Reference Example 3 were excellent in borate ion adsorbability, whereas the adsorbents of Comparative Examples 1 to 3 were low in adsorbability. Moreover, the adsorbent of Example 4 was excellent in the adsorptivity of germanium. Further, the adsorbent of Example 5 was excellent in nickel adsorptivity.

The embodiments of the present invention have been described above with reference to specific examples. The embodiments of the present invention are not limited to these specific examples. It is included in the scope of the present invention as long as a person skilled in the art can carry out the present invention by selecting appropriately from the known ranges and obtain the same effect.

In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .

Claims (4)

(4) An acrylic resin for adsorbent having a structural unit represented by the formula: (R1 is hydrogen or a methyl group, R3 is a branched alkyl chain, R6, R8 contains a polyol containing an alkyl chain, iminodiacetic acid, polyamine, sulfo group, carboxyl group, and at least one of amino groups. The alkyl chain, R7 is an alkyl group having a structure in which an epoxy group is opened, and n is an integer of 3 to 1,000,000.)

The acrylic resin for adsorbents according to claim 1 , which has a structural unit represented by the formula (5). (R1 is hydrogen or a methyl group, R9 is an alkyl group having a structure in which an epoxy group is opened, R10 is an N-methylglucamine, R11 and R12 are alkyl groups having a structure in which a hydrogen, an epoxy group or an epoxy group is opened. N-methylglucamine bound to, n is an integer from 3 to 1 million.)

A water treatment column packed with the acrylic resin for adsorbent according to claim 1 or 2 . A water treatment method for purifying water by passing water through the water treatment column according to claim 3.

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