JPH034940A - Preparation of inorganic ion exchange body - Google Patents

Abstract

PURPOSE:To obtain the subject exchange body improved in dispersibility, flowability and the close adhesiveness to a solid material and reduced in a lowering of ion exchange capacity by adding a coupling agent aqueous solution to a reaction system when a water-soluble metal salt is hydrolyzed by water and/or an alkaline substance. CONSTITUTION:In hydrolyzing a water-soluble metal salt by water and/or an alkaline substance, by adding a coupling agent aqueous solution to a reaction system on the way of reaction or at the point of time when reaction is complet ed, an inorg. ion exchange body represented by formula I [MA<+> is a metal ion of valence A+ (A is an integer of 2-5), XB<-> is an anion of valency B-(B is a positive number), D and F are 0 or a positive number and E is positive number] is obtained. As the coupling agent to be used, one having a functional group having the compatibility with a solid material to which it is added and, for example, gamma-glycidixypropyltrimethoxysilane is pref. used in case of the addi tion to an epoxy resin.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention is applicable to various applications that utilize ion exchange and ion adsorption, such as the removal of impurity ions in aqueous solutions and organic solvents,
of harmful ions in industrial wastewater. removal, recovery of valuables from industrial wastewater and seawater, production of high-purity chemicals, adsorption and fixation of impurity ions in electrical and electronic materials, adsorption recovery or adsorption removal of ionic components in gases, and the use of ion exchange. pH
The present invention relates to a method for producing an inorganic ion exchanger suitable for use in applications such as pH adjustment and pH adjustment.

[Conventional technology]

As one method for producing an inorganic ion exchanger, a method is known in which a water-soluble salt of a metal is subjected to a sequential hydrolysis reaction as described in (1) 2 below.

(MA+)II (XB-)A+a ・(Z”) (Kano-)
D→B・(MA+)(02-)+1(OH-)E(X
B-)F+(a/B) ・(ZC-)a(Xl'-)
C+BD-H,O...(1) where MA+ is a metal ion with valence A+ (A is a positive number),
Xl'- represents an anion with a valence of B- (B is a positive number), and ZC- represents a metal ion, hydrogen ion, or ammonium ion with a valence of C+ (C is a positive number).

Also, a is a positive number, D and F are O or a positive number, E is a positive number, and (2D+E) ・B=a-c and A-=
Satisfies 2D+E+BF.

Among the inorganic ion exchangers obtained by this method, those with a low degree of hydrolysis, that is, those with a large amount of XB- still remaining in their structure, have relatively excellent fluidity and dispersibility. , those with a high degree of hydrolysis have poor fluidity,
It has poor dispersibility, and when attempting to separate the reaction product from the reaction solution and wash it with water, it tends to form blocks, making subsequent drying and pulverization difficult.

Furthermore, even if pulverization is possible, when the resulting product is added to a solid material, especially an organic material such as an epoxy resin, the adhesion or affinity with the solid material is often poor, and the The brittleness of the solid material is poor (sometimes cracks occur when heat is applied).In addition, the adsorption and fixation performance of impurity ions in the solid material decreases due to poor dispersion into the solid material. Since the viscosity increases when mixed, there is also the drawback that the amount added is limited when trying to mix uniformly.

In the past, attempts have been made to develop composite materials that have the potential to create new properties by combining inorganic and organic materials, and in this case, coupling agents are used to connect the inorganic and organic materials. is publicly known.

The present inventors thought that treating an inorganic ion exchanger with a coupling agent might be effective in improving the adhesion and dispersibility when adding the inorganic ion exchanger to a solid material.

Coupling agents include silane-based, titanium-based, etc., and are used to bind different substances together through chemical bonding and interaction at the interface, and to modify surfaces and interfaces.

In general, methods for surface treatment of inorganic materials using a coupling agent include a method in which the coupling agent is used as an aqueous solution with a concentration of several percent, and (1) the dry inorganic material is stirred and the aqueous solution of the coupling agent is sprayed or vaporized and dispersed. (2) A method of dispersing the dried inorganic material in water again to form a slurry, and adding an aqueous coupling agent solution to the slurry while stirring, and (3) adding an aqueous coupling agent solution to the high-temperature inorganic material after drying. A method of vaporizing and dispersing it in the form of a spray is known.

[Problem to be solved by the invention]

The method for surface treatment of inorganic materials using the above coupling agent,
When applied to inorganic ion exchangers, there are the following drawbacks.

That is, in methods (1) and (3), it is necessary to have good dispersion of the inorganic material in order to improve the uniform treatment and treatment efficiency, but the inorganic ion exchanger obtained by the sequential hydrolysis method When dried, it forms blocks and is unsuitable for uniform treatment.

Furthermore, when coupling treatment is performed using these methods, the ion exchange capacity of the inorganic ion exchanger may be significantly reduced if the amount of coupling agent sprayed is large or unevenly distributed. .

This means that the ion exchange group of the inorganic ion exchanger is an active OH
However, because this group easily bonds with the silanol group of the coupling agent, the OH group involved in ion exchange bonds with the coupling agent more than necessary, resulting in a decrease in ion exchange capacity. it is conceivable that.

On the other hand, method (2) can be processed uniformly and has good processing efficiency, but it requires extra steps of refiltration and redrying in order to redisperse the dried material in water and process it. However, there was a cost problem.

(B) Structure of the Invention [Means for Solving the Problems] As a result of intensive studies to solve the above problems, the present inventors found that when producing an inorganic ion exchanger by sequential hydrolysis reactions,
By adding a water-soluble coupling agent to the reaction system,
It has excellent dispersibility and fluidity, making it easy to dry and grind the product, and when added to solid materials, it has excellent adhesion and affinity with solid materials, and reduces ion exchange capacity. The present inventors have discovered that it is possible to obtain an inorganic ion exchanger that does not contain any of the following.

That is, the present invention provides a method for producing an inorganic ion exchanger in which a water-soluble salt of a metal is hydrolyzed with water and/or an alkaline substance, which is represented by the following formula, characterized in that an aqueous solution of a coupling agent is added to the reaction system. This is a method for producing an inorganic ion exchanger.

(M^tsu(0”)o (OH-)F (X ”-)F where MA+ is a metal ion with valence A+ (A is an integer from 2 to 5), xi- is a valence B- (B is Indicates an anion (positive number).

Further, D and F represent 0 or a positive number, and E represents a positive number.

The sequential hydrolysis reaction is shown by the above-mentioned formula (1), and the metal ion MA+ with a valence of +2 to +5 constituting the water-soluble salt (MA'') and (XB-)A, which are the starting materials, is as follows. These include:

Valence is +2: FeXCo, Ni, Cu, Zn
, Pb valence is +3: Fe, AI, Sb, Bi
Valence is +4: Ti, Zr, Mn, Si, S
n valence is +5: Sb Among the above, Pb, AI, Sb, Bi, Ti,
Zr and Sn are preferred because they have a large ion exchange capacity when used as inorganic ion exchangers, and Bi is more preferred.

The type of anion or anionic group X which is the other component is not particularly limited as long as it forms a water-soluble salt with M.

Hydrolyze the above water-soluble salt (Z”) (OH-)
c is water or a water-soluble alkaline substance (hereinafter referred to as "alkaline substance"), and ZC- is an alkali metal ion, an alkaline earth metal ion, a hydrogen ion, or an ammonium ion.

The inorganic ion exchanger finally obtained when the sequential hydrolysis reaction is completed is a hydrous oxide (oxyhydroxide) of the metal M.

The present invention provides a water-soluble salt of the metal element M (MA″)R(X
The present invention relates to a method for producing an inorganic ion exchanger by hydrolyzing l'-)A with an alkaline substance and adding an aqueous coupling agent solution to the reaction system during or at the end of the reaction.

The hydrolysis reaction in the present invention is preferably carried out by first making the required amount of metal water-soluble salt present in the reaction system, and then adding an alkaline substance to the system successively or intermittently.

The coupling agent used in the present invention may be either silane-based or titanium-based as long as it is water-soluble, but it has no affinity with solid materials when an inorganic ion exchanger is added to the solid material. Considering this, it is desirable to have a functional group that has an affinity with the solid material.

For example, when an inorganic ion exchanger is added to an epoxy resin, preferred coupling agents include T-glycidoxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, N- β(
aminoethyl) γ-aminopropylmethyldimethoxysilane, T-mercaptopropyltrimethoxysilane, γ
-aminopropyltrimethoxysilane and the like.

Next, the timing of adding the coupling agent will be described.

In general, the hydrolysis reaction of an aqueous metal salt solution with an alkaline substance can be expressed by the above formula (1), and as the alkaline substance is added, hydrolysis products (hereinafter referred to as "products") are successively produced. .

The number of OH groups in the product gradually increases with the addition of the alkaline substance, and when the amount AB of the water-soluble metal salt used becomes equal to the amount aC of the alkaline substance added, hydrolysis is completed.

When an aqueous coupling agent solution is added during the reaction, a dehydration condensation reaction occurs between the functional groups in the coupling agent and the OH groups in the product.

In the early stage of the hydrolysis reaction, that is, when AB/2≧aC, there are few OH groups present in the product, and condensation of the OH groups with functional groups such as silanol groups in the coupling agent is difficult to occur. Furthermore, the inorganic ion exchanger obtained by completing the hydrolysis reaction at this point has relatively good fluidity and dispersibility by itself, and the effect of adding a coupling agent is not so great.

When the hydrolysis reaction progresses and AB=aC1, that is, the product becomes a complete oxyhydroxide, when an aqueous coupling agent solution is added, a large number of OH groups are present in the product, but the Since the liquid becomes alkaline, the condensation reaction between functional groups such as silanol groups in the coupling agent and OH groups in the product is inhibited.

Note that if the reaction is carried out without adding a coupling agent and the product is separated from the reaction solution, it is difficult to add a coupling agent because the inorganic ion exchanger will block as described above. be.

Therefore, in the coupling agent aqueous solution, the relationship between the amount AB of the water-soluble metal salt used and the amount aC of the alkaline substance added is AB/2.
It is preferable to add at the stage of <aC<AB, more preferably (6/10) ・AB<a C< (9/
10) - It is within the range of AB.

The timing of addition of the coupling agent aqueous solution can also be determined from the composition analysis ε of the product, but for boat fishing, determine the raw material water-soluble metal salt and the type of alkaline substance to be added, and follow the reaction equation (1). Calculate the amount of alkaline substance necessary to obtain a product with the desired composition, add this amount to the reaction system, and then add the coupling agent aqueous solution when the alkaline substance is consumed. good.

Consumption of the total amount of alkaline substances can be determined by no change in the pH of the reaction solution.

In the present invention, after addition of the coupling agent, addition of the alkaline substance can be continued until the inorganic ion exchanger has the desired composition.

The amount of alkaline substance added necessary to obtain the final product can be determined according to the above formula (1), and the end point of the reaction can be determined by pH measurement.

The alkaline substance used in hydrolysis is preferably added to the metal salt aqueous solution using a metering pump while stirring.

Although the addition rate is desirably adjusted to the hydrolysis reaction rate, it is also possible to add the amount of alkaline substance necessary to obtain the product first and wait for equilibrium to be reached. However, B
In the case of an i-based inorganic ion exchanger, if the pH rapidly increases, it may crystallize and reduce its ion exchange ability, so it should be avoided to add a large amount of an alkaline substance at once.

It is preferable that the concentration of the alkaline active substance be low after the addition of the coupling agent aqueous solution so that the composition can be easily controlled.

Next, the amount of the coupling agent added will be described.

When coupling the surface of a general inorganic substance, the amount of the coupling agent added is determined based on the specific surface area (minimum coverage area) of the coupling agent used and the specific surface area of the substance to be surface-treated. Calculate and determine the amount needed to form a molecular layer.

In the present invention, it is thought that the surface of the produced inorganic ion exchanger is coated with the force/7 pulling agent, but when the amount obtained by the above calculation is applied to the inorganic ion exchanger,
Not only is the surface of the inorganic ion exchanger extensively covered with a monomolecular layer of the coupling agent, but also the OH group, which is an exchange group involved in ion exchange, of the inorganic ion exchanger is covered with a functional group such as a silanol group of the coupling agent. Condensation may occur, and as a result, the ion exchange capacity of the inorganic ion exchanger may decrease rapidly.

Therefore, the amount of the coupling agent added is preferably such that the number of functional groups thereof is smaller than the number of equivalents of OH groups in the final product, and may be determined within this range depending on the intended use.

For example, O that you want to ultimately leave in the inorganic ion exchanger
Determine the number of equivalents of H group, and add anion (X ”
-) All A is hydrolyzed to convert into OH groups, and then the O
There is a method in which a coupling agent having a number of functional groups corresponding to the number of H groups is added and all are reacted, and then an alkaline substance is added to the thread to convert the entire amount of unreacted anions into OH groups.

Alternatively, it is more convenient to add several different amounts of the coupling agent on a trial basis to generate a surface-treated inorganic ion exchanger, test its performance, and then determine the most preferable amount. There is a way.

[Effect]

The inorganic ion exchanger obtained by the present invention has excellent fluidity and dispersibility even if it is a product obtained through a highly hydrolyzed reaction, and the product can be separated from the reaction solution and washed with water. It is also difficult to form into blocks (and subsequent drying and pulverization are also easy).

Furthermore, the ion exchange capacity is the same as that of conventional products (and the affinity and dispersibility with other solid materials are also excellent).

The reason for this is not clear, but in the present invention, by specifying the timing of addition of the coupling agent, it is possible to have any amount of the coupling agent present on the surface of the inorganic ion exchanger, and when added to the solid material, It is thought that this contributes to the affinity with the solid material, while the remaining 0H groups that did not react with the force-twisting agent or the OH groups generated by the subsequent reaction with the alkaline substance contribute to ion exchange.

[Example] Hereinafter, the present invention will be explained in more detail by giving Examples and Comparative Examples. Note that "parts" on each side represent "parts by weight."

Example 1 600 g of bismuth nitrate aqueous solution (bismuth nitrate content 40.9%, free nitric acid 5.2%) was added at a temperature of 15 to 15% while stirring.
At 25°C, add 15% sodium hydroxide aqueous solution 6.
80 g was added over 30 minutes using a metering pump, followed by stirring for 30 minutes.

When a portion of the obtained slurry was taken and the composition of the reaction product was analyzed, it was found that BihO6(OH) 3.11 (NOz
)z-0・0.9H20.

Silane coupling agent (A-187, manufactured by Nippon Unicar Aji; T-glycidoxyprobyltrimethoxysilane, average molecular weight 236.1 molecule trifunctional (3 silanol groups are present in one molecule).

) and 100 g of pure water were added to the resulting slurry and stirred for 60 minutes to allow sufficient reaction.

Subsequently, 600 g of a 2% aqueous sodium hydroxide solution and 1500 g of a 4% aqueous sodium hydroxide solution were each added over 1 hour using a metering pump.

The resulting slurry was filtered through Nα2 filter, washed with distilled water, dried in a box-type dryer at 110°C for 115 hours, and then ground in a tabletop grinder to produce an inorganic material with a composition of Bi, 06(OH)b. Approximately 150 g of ion exchanger powder was obtained.

Example 2 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
Added over 0 minutes.

After stirring for 30 minutes, the same silane coupling agent 3 as in Example 1 was added.
An aqueous solution consisting of 100 g of pure water and 100 g of pure water was added to the produced slurry, and stirred for 60 minutes to sufficiently carry out the reaction.

Thereafter, the same operation as in Example 1 was performed to obtain powder of an inorganic ion exchanger.

Example 3 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
Added over 0 minutes.

After stirring for 30 minutes, the same silane coupling agent 1 as in Example 1 was added.
．． An aqueous solution consisting of 5 g and 100 g of pure water was added to the resulting slurry and stirred for 60 minutes to allow sufficient reaction.

Thereafter, the same operation as in Example 1 was performed to obtain powder of an inorganic ion exchanger.

Example 4 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
Added over 0 minutes.

After stirring for 30 minutes, the same silane coupling agent 0 as in Example 1 was added.
．． An aqueous solution consisting of 75 g and 100 g of pure water was added to the resulting slurry and stirred for 60 minutes to ensure sufficient reaction.

Thereafter, the same operation as in Example 1 was performed to obtain powder of an inorganic ion exchanger.

Example 5 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
The mixture was added over 0 minutes and then stirred for 30 minutes. 2% thereafter
600 g of aqueous sodium hydroxide solution was added over 30 minutes using a metering pump.

A portion of the obtained slurry was taken and the composition of the reaction product was analyzed, and it was found that B110b (OH) 4.2 (NO+
) 8. -・o, 5Hz.

1.5 g of the same silane coupling agent as in Example 1 and 1 portion of pure water
An aqueous solution consisting of 00 g was added to the resulting slurry and stirred for 60 minutes to ensure sufficient reaction.

Subsequently, using a metering pump, 1500 g of 4% sodium hydroxide aqueous solution and 1500 g of 4% sodium hydroxide aqueous solution were added.
Added over 1 hour.

After stirring for 30 minutes, the same operation as in Example 1 was performed to obtain an inorganic ion exchanger powder.

Example 6 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
The mixture was added over 0 minutes and then stirred for 30 minutes. 2% thereafter
600 g of aqueous sodium hydroxide solution was added over 30 minutes using a metering pump.

Furthermore, 1500 g of 4% aqueous sodium hydroxide solution was added over 1 hour using a metering pump.

After stirring for 30 minutes, a portion of the obtained slurry was taken and the composition of the reaction product was analyzed, and it was found that B160h (OH)
b, o・0.9HzO.

1.5 g of the same silane coupling agent as in Example 1 and 1 portion of pure water
An aqueous solution consisting of 00 g was added to the resulting slurry and stirred for 60 minutes to ensure sufficient reaction.

Thereafter, the same operation as in Example 1 was performed to obtain a powder of an inorganic ion exchanger.

Comparative Example 1 680 g of a 15% sodium hydroxide aqueous solution was added to 600 g of the same bismuth nitrate aqueous solution as in Example 1 using a metering pump.
The mixture was added over 0 minutes and then stirred for 30 minutes. 2% thereafter
600 g of aqueous sodium hydroxide solution was added over 30 minutes using a metering pump.

Furthermore, 1500 g of 4% aqueous sodium hydroxide solution was added over 1 hour using a metering pump.

Thereafter, the same operation as in Example 1 was performed to obtain a powder of an inorganic ion exchanger.

Comparative Example 2 50 g of the inorganic ion exchanger powder obtained in Comparative Example 1 was added to 200 ml of pure water and stirred for 10 minutes to disperse it.

While stirring the dispersion, an aqueous solution consisting of 1.5 g of the same silane coupling agent as in Example 1 and 100 g of pure water was added over 10 minutes.

After stirring for an additional 30 minutes, the slurry was filtered, washed, and dried in the same manner as in Example 1 to obtain an inorganic ion exchanger powder.

Comparative Example 3 50 g of the inorganic ion exchanger powder obtained in Comparative Example 1 was placed in a tabletop pulverizer, a 1.5% aqueous solution of the same silane coupling agent as in Example 1 was added, mixed for 10 minutes, and then dried. A powder of an inorganic ion exchanger was obtained.

As described above, 1.0 g of each of the inorganic ion exchanger powders obtained in Examples 1 to 6 and Comparative Examples 1 to 3 was added to 0.0 g. IN aqueous hydrochloric acid solution 50
ml, stirred at 25°C for 15 hours, filtered, measured the chloride ion concentration in the supernatant, and examined the chloride ion exchange ability of each (Test 1). The dispersibility, fluidity, and adhesion of the inorganic ion exchanger powders obtained in Comparative Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated using a powder tester manufactured by Hosokawa Micron (Test 2). , the standard sieve is vibrated, the sample is passed through the funnel, and the serum angle is measured by the injection method. The degree is determined by measuring the loose apparent specific gravity and the hardened apparent specific gravity, and then calculating the ratio of these two values. - The results of Tests 1 and 2 are shown in Table 1.

Each of the inorganic ion exchangers obtained in Examples 3 to 6 and Comparative Example 1 was added in an amount of 50% by weight to a liquid epoxy resin (Yuka shell side type, Epicoat 828), and kneaded for 3 cycles using 3 rolls.

2.5 g of the obtained sample was taken, and its viscosity was measured using an E-type viscometer under the following measurement conditions.

Temperature: 25° C. Rotation speed: 10 rpm, 5 rpm, l rpm, and the viscosity was measured after 10 minutes. The results are shown in Table 2.

Furthermore, the affinity of the inorganic ion exchanger with solid materials was measured.

(c) Effects of the Invention According to the present invention, it is possible to produce an inorganic ion exchanger product that is difficult to form blocks even in the filtration and washing steps and is extremely easy to dry afterwards.

Furthermore, the ion exchange capacity of the inorganic ion exchanger obtained in the present invention is the same as that of conventional inorganic ion exchangers, and it has excellent affinity and dispersibility when added to solid materials such as epoxy resins.

The inorganic ion exchanger obtained by the present invention is suitably used for IC sealing materials, capacitor sealing materials, electrolytic capacitor sealing materials (rubber or resin), substrates, pastes, and the like.

Claims (1)

[Claims] 1. A method for producing an inorganic ion exchanger in which a water-soluble salt of a metal is hydrolyzed with water and/or an alkaline substance, characterized by adding an aqueous coupling agent solution to the reaction system, according to the following formula: A method for producing an inorganic ion exchanger represented by (M^A^+) (O^2^-)_D(OH^-)_E(
X^B^-)_FHere, M^A^+ is the valence A+ (A is 2
~5 integer) metal ion, X^B^- has a valence of B- (B
is a positive number). Further, D and F represent 0 or a positive number, and E represents a positive number.