JPS6360112A - Bismuth compound and inorganic ion exchanger containing same as effective component - Google Patents

Abstract

PURPOSE:To obtain a bismuth compd. expressed by a specified chemical formula, having both a large ion-exchange capacity and a large ion-exchange velocity, and useful as an inorganic ion exchanger having excellent stability by hydrolyzing bismuth nitrate. CONSTITUTION:The bismuth compound usable as effective component of the inorganic ion exchanger is expressed by the following formula, namely, Bi6 O6(OH)x(NO3)6-x.nH2O (wherein 3.5<=x<=5.5; n is 0 or a positive number). The bismuth compd. is obtained by hydrolyzing an aq. nitric acid soln. of bismuth nitrate with alkali in the controlled condition, filtering and washing the reaction product, and then drying and crushing, as required.

Description

Detailed Description of the Invention (1) Purpose of the Invention [Field of Industrial Application] The present invention is directed to a novel bismuth compound and various uses thereof, such as ion exchange and adsorption, such as removal of impurity ions from aqueous solutions and organic solvents. removal, treatment of industrial waste liquid, recovery of valuables from industrial wastewater and seawater, preparation of high-purity chemicals, adsorption and fixation of impurity ions in solid materials related to electrical and electronic fields, adsorption and recovery of ionic components in gases, and Adsorption removal, ion exchange, pil buffer using adsorption properties, p T-1
It relates to inorganic anion exchangers used for purposes such as adjustment.

[Conventional technology]

Conventionally, hydrous magnesium oxide, hydrous aluminum oxide, hydrous zirconium oxide, hydrous titanium oxide, hydrous tin oxide, hydrous thorium oxide, hydrous iron oxide, hydrous bismuth oxide, hydrotalcite, hydroxyapatite, etc. have been known as inorganic anion exchangers. It is being

Generally speaking, inorganic ion exchangers, including inorganic anion exchangers, are amphoteric exchangers. That is, it exhibits cation exchange properties on the alkaline side and anion/ion exchange properties on the acidic side.

If the inorganic ion exchanger is M (Oll) n, and the ions to be captured are represented by I3'' and A-, then on the alkaline side (1
), ion exchange is performed on the acidic side as shown in equation (2).

M (OH)n +B0-”M (011)n-
+OB +H”...(1)M (OH) TI+A
-≠M (OII) TI-+HA+○H-...(2
) p where the anion exchange reaction and the cation exchange reaction are equal
H is called the isoelectric point, and at p II near this point, it appears that neither positive cation exchangeability nor anion exchangeability is exhibited.

The isoelectric point varies somewhat depending on the type of ion exchanger, but is generally around pH5.

For example, hydrous zirconium oxide has a pH of about 6, hydrous titanium oxide has a p II of about 4, and hydrous tin oxide has a p T (about 5).

As is clear from this, inorganic ion exchangers have the disadvantage that they do not exchange ions near neutrality.

Furthermore, in the case of inorganic anion exchangers, there is also the problem of liquid contamination.

That is, after adsorbing anions on the acidic side, when desorbing the adsorbed ions (regenerating the ion exchanger), an alkaline aqueous solution such as NaOH aqueous solution is usually used, but inorganic ion exchanger that has been subsequently subjected to desorption treatment When the body is brought into contact with an acidic solution again to adsorb anions, the following ion exchange reaction occurs, and the adsorbed cations, such as Na, during regeneration become ai
! This reaction contaminates the liquid, and furthermore, this reaction increases the p II of the liquid, which approaches the isoelectric point and reduces the ion exchange capacity.

M (OH) n-+ (013) +II" CI-
r"M (011) n + B" CI - For the reasons stated above, inorganic ion exchangers having an isoelectric point in the vicinity of weak acids to neutrality have poor practicality as anion exchangers.

In addition, hydrated aluminum oxide and hydroxyapatite have a small ion exchange capacity, and hydrated magnesium oxide has a large solubility, making them difficult to use industrially.

Hydrotalcite and hydrous bismuth oxide exhibit only anion exchange properties and have relatively excellent chemical resistance and heat resistance.

However, hydrotalcite is highly soluble in hot water at temperatures of 100°C or higher and has poor heat resistance.

- Perfect bismuth hydroxide has a very large exchange capacity in acidic conditions and is stable in water, making it relatively excellent as an inorganic ion exchanger, but its ion exchange capacity near neutrality is low and the exchange rate is It also has the disadvantage of being slow.

In the literature, hydrous bismuth oxide used as an inorganic anion exchanger has various chemical formulas as shown below.

Bi(C1) ko, Bi 20 ko・3
H20, ■lBiO2, 11 B4O, HBf0
2, B10-0II (more than 1N0RGANICIO
Nt! XCIIANG MATURIALS, C
RCPress, Inc. (Iloca Raton
, Florida), 1981 publication P, 180-1
82).

These compounds can be obtained by hydrolyzing an aqueous solution of a soluble salt of bismuth, but common manufacturing methods include neutralizing an aqueous solution of bismuth nitrate with aqueous ammonia, or diluting an aqueous solution of bismuth mannitol complex with a large amount of water and hydrolyzing it. There are known methods to do this.

[Problem that the invention seeks to solve]

Conventional hydrous bismuth oxide, which is relatively excellent as an inorganic anion exchanger, has the drawbacks of low ion exchange capacity near neutrality and slow exchange rate, as described above.

Therefore, there has been a strong demand for inorganic anion exchangers that are stable, highly basic, and have a high ion exchange rate, especially inorganic anion exchangers made of bismuth-based compounds.

(2) Structure of the invention [Means for solving the problem] The inventors,
As a result of intensive research into the synthesis of a new hydrous bismuth oxide that can be used as an inorganic anion exchanger, we succeeded in synthesizing a new bismuth nitrate hydrolysis product. It was confirmed that an inorganic anion exchanger with high speed and excellent stability could be obtained, leading to the completion of the present invention.

That is, the present invention provides B is O6 (OIHχ (N.

:l) ix”n1120 (However, 3.5≦χ≦5
．． 5, n is 0 or a positive number) and an inorganic anion exchanger containing this compound as an active ingredient.

[Bismuth compound B 1GOs (Of()χ (M
oko))X-nl20 (However, 3.5≦χ≦5.5,
n is O or a positive number)] In the field of crystal chemistry research of inorganic compounds, the hydrolysis reaction product of bismuth has been studied in relatively detail. The chemical species that are present include:

0BiO・No, (Bismuth oxynitrate)○ (B
iG 04 (OII) 4 ) (Oll) (
Moko) 5・0.5H20 (pI! 1.04-1.8
Product at 8) 0 (I3 is Os (OH)) (M
o co)5・2.5H20 0(I3iGOs (OH)2)(No:I)4・2
H20 0(B iG 0G (O)H co] (N
Oko) 3・1.51120 0 (B iG 04 (OIN) 4)
(No))e・41120 (Monatshefte fur Chemie 1
04+365-375 (1973), Cr
yst, 5truct, Comm, (1979)
, 8.69. ) What all the above compounds have in common is that the hydrolysis product of bismuth is an oxy compound and is a polymer, and the basic unit is six bismuth atoms. So, B
The established theory is that the i-ring atoms occupy six vertices of an octahedral structure.

However, ion exchange studies of the above-mentioned chemical species have not been conducted.

Additionally, the species mentioned above are products of the low p II range and are all low basic.

That is, the OH group/N 2 O3 group ratio of each chemical species is 1 or less, and no basicity higher than this has been reported so far.

The bismuth compound of the present invention can be produced by adding an alkaline aqueous solution to a nitric acid aqueous solution of bismuth nitrate while controlling the hydrolysis reaction conditions.

As mentioned above, the basic unit of the hydrolysis product of bismuth is an oxy compound containing 6 Bi atoms, and B is
06 (OI-I) x (Moko)shiX・nl(
20.

So far, materials with an x/6-x ratio of 1 or less have been found, but none have been found to have an x/6-x ratio of 1 or less.

The conventional hydrolysis reaction of a compound in which the x/6-x ratio is 1 or less, that is, X is 3 or less, is estimated as follows.

Qpl(Reaction in solution below 1 6B i”+121120≠B i 6(OII)+z
+12 ■1”...(3) Oxygenation precipitation reaction B iG near Qpll, 2
(011),, +6NOko -→ B15O6
(No)s+611zO... (4) Here, Bi2O2(Mo)6 is generally represented as B10N0:+ as bismuth oxynitrate.

Furthermore, in the hydrolysis reaction at high p II, B160s(N
Ch) OB iG 0G (No: l ) r in which the NO cogroup of s is successively substituted with 011.

II3 ig OG (CN-1) CN
O3)5”(5)OB iG 06 (Of
() (Moko)6→I3 is Os (
OII) 2 (Moko) 4 ... (6) OB
iG OG (Ofri 2 (NOI)
4→B is Or, (OII)
(No,) (7) All of the above chemical species have hydration water.

As mentioned above, the production of a more basic compound containing a nitric acid group has not been reported.

The reason for this is that the final sequential reaction product, B 160g (OII) s, is a structural modification of the known 3(Bi201+・1120
This is presumed to be because it is easy to metastasize to ).

However, the present inventors have discovered that by adding an alkaline aqueous solution while controlling the hydrolysis reaction conditions as described below,
Previously unknown, B160G (OII) x
(NOz) We investigated stable and useful hydrated bismuth oxide with r and x in the range of 3.5 to 5°5, succeeded in obtaining the target compound, and completed the present invention. I let it happen.

[Production method of new bismuth compound]

The starting material is a solution of bismuth nitrate in nitric acid.

It is prepared by dissolving bismuth compounds such as bismuth nitrate, bismuth carbonate, and bismuth oxide in nitric acid.

Here, bismuth nitrate will not dissolve unless it is in an acid solution, so
It is necessary to have an excess of nitric acid.

The concentration of the resulting bismuth nitrate solution is not particularly specified, but B
It is preferably 20 to 50% by weight in terms of i (No.).

If the concentration is higher than 50% by weight, the slurry concentration becomes high and uniformity is inhibited in the subsequent reaction in which an alkali is added to precipitate.

On the other hand, if it is less than 20% by weight, the yield per batch will be small (and uneconomical).

There is no particular regulation regarding the concentration of free nitric acid present in excess; it is sufficient that bismuth nitrate does not precipitate and remains dissolved. However, if the amount of free nitric acid is in excess, it may be added in the next step. Since the amount of alkali produced increases, it is disadvantageous economically and operationally.The preferred concentration of nitric acid is 3 to 10% by weight.

The next step is to hydrolyze bismuth nitrate using an alkali.

The type of alkali is not particularly limited, and examples thereof include lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, and sodium hydrogen carbonate.

The addition rate of the alkali is preferably adjusted to the hydrolysis equilibrium.

That is, since the hydrolysis reaction shown in the above-mentioned formula (3) (41) proceeds quickly, and the reactions in formulas (5) to (7) are slow, they are added accordingly.

Equations (3) and (4), including the meaning of maintaining the uniformity of the solution,
Until the reaction shown by , it is preferable to add a predetermined equivalent amount of alkali, that is, the amount of alkali necessary to completely carry out the hydrolysis, over a period of about 2 hours.

The alkali addition time required for formulas (5) to (7) is 60 to 1
A range of 80 minutes is preferred.

From now on, B ig 0G (OII) x (N
In order to increase X in O3) e-x by 1, it is preferable to add about 1 mol of alkali to increase the predetermined molar value m, that is, 1 in 2 to 6 hours.

The reason for this is that the equilibrium reaction is slow after Equation (7), so if the addition time is short, OH is not consumed, and the pH of the reaction solution becomes higher than necessary, resulting in undesirable products such as Bi20) and lI20. This is because metastasis may progress.

On the other hand, if the addition time is too long, there is a risk of metastasis occurring, which is undesirable.

The concentration of the aqueous solution of the alkaline substance used for hydrolysis is not particularly limited, but it generally depends on the addition time. ) and later), it is desirable to lower the concentration in order, with the concentration preferably being about 20% by weight in the first period, about 10% by weight in the middle, and about 5% by weight in the latter period.

Whether the temperature of the hydrolysis reaction is high or low, it does not have much effect on the composition of the final product, but the amount of products produced at low temperatures dissolved in hot water is greater than those produced at high temperatures. It has the disadvantage of being slightly inferior in heat resistance.

Also, the reaction rate decreases as the temperature decreases, so
The preferred reaction temperature is 10-60°C, more preferably 20-50°C.

The reaction product is filtered, washed with water, and if necessary, dried and pulverized.

Any drying method may be used as long as attached water can be removed.

B ig 0g (OII)χ produced in the present invention
(N O3) 6< ・n l-120 (However, 3.5
≦χ≦5.5, n is O or a positive number) n1I20 of the compound is hydration water, where the value of n is usually O ~
Although it is approximately 0.8, it can be adjusted by changing the drying temperature, drying time, and drying method in the drying process.

Particularly when using organic solvents or solid systems, if desorption of water is inconvenient, it may be adjusted during drying.

The method of pulverization is not limited as long as it can be pulverized to a particle size suitable for the purpose of use.

[Effect]

Present invention (7) B is C6 (OIL) x (NO
I) s-x・nI(20 (however, 3.5≦χ≦5.
5, n is 0 or a positive number) When used as an inorganic anion exchanger, the compound has a higher ion exchange capacity and exchange rate near neutrality than ordinary hydrous hismuth oxide, and It also has excellent heat resistance.

Here, the value of X can be freely determined by measuring the weight and concentration of the raw material used with high precision and then adding a calculated amount of alkali under the above conditions.

The ion exchange groups of this compound are both the No3 group and the C11 group, but the NO group has a larger ion exchange capacity and exchange rate than the OI-I group.

Therefore, this compound has a large ion exchange capacity and rate near neutrality.

This difference is particularly remarkable for halogen ions such as F-1CI-1Br-.

If the value of
Water resistance and heat resistance are significantly reduced, such as increased elution of.

Furthermore, as X becomes smaller, the solubility of the compound itself also becomes larger.

On the other hand, when X is larger than 5.5, NO in the compound
Since the number of three groups is small, the ion exchange capacity and exchange rate near neutrality are small, and the structure is similar to normal hydrous bismuth oxide, resulting in poor water resistance.

[Inorganic anion exchanger]

B is OG (OIL) x (No
j) 6-χ・nH2O (However, 3.5≦χ≦5.5, n
As mentioned above, inorganic anion exchangers made of compounds represented by 0 or a positive number have high ion exchange capacity and exchange rate near neutrality, and also have excellent water resistance and heat resistance. It can be used in a wide range of fields of application.

Further, the compound of the present invention may be used in combination with an inorganic cation exchanger such as crystalline antimony.

The shape of the inorganic anion exchanger of the present invention is not particularly limited, and may be selected depending on the purpose of use, such as powder, granules, granules, structures such as honeycomb, and membrane.

When molding into particles or the like, an organic and/or inorganic binder can be used.

When molding into a structure, the inorganic anion exchanger itself can be molded using a binder, or the inorganic anion exchanger can be supported on another structure.

When forming into a membrane, there are methods such as forming the inorganic anion exchanger itself into a membrane, and adding the inorganic anion exchanger to the paper making process to form paper.

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In addition, "%" in the examples means "weight %", "
"Parts" means "parts by weight."

The method for analyzing the concentration of bismuth nitrate and free nitric acid in an aqueous solution containing excess nitric acid is as follows.

(2) Measure out a certain amount of bismuth nitrate aqueous solution, dissolve it in a large amount of water, and add NaCl aqueous solution to it.

■According to the following reaction formula, bismuth precipitates and NO coco-
to be released.

I3 i <NO3) 3 + Na
Cl +II2 0-BiOCI↓+NaN0:l
The amount of free nitric acid and free nitric acid is determined by neutralization titration.

■Meanwhile, the bismuth concentration of bismuth nitrate aqueous solution was determined by chelate titration (titration reagent EDTA; indicator xynol orange).
Find it with

(2) Subtracting what corresponds to Bi (No. 34 degrees) obtained above, the concentration of free nitric acid can be found.

Furthermore, the composition of the bismuth compound that is the product is determined by dividing a certain amount of sample into 0. It was determined by adding 1N-Na11 (into an aqueous solution) and measuring the elution number by ion chromatography after stirring for 24 hours. Further, the moisture content was determined from the weight of the sample that decreased as a result of drying at 200° C. for 2 hours.

Example 1, Comparative Example 1 and Comparative Example 2 236 g of bismuth oxide was dissolved in 764 g of 31.5% nitric acid.

Analysis of the concentration of bismuth nitrate in the solution revealed that 13i (
It is 40.2% in terms of No.), and free nitric acid is 4.9.
It was 0%.

While maintaining the reaction temperature at 25° C., 563 g of a 20% aqueous sodium hydroxide solution was added to this solution over 1 hour using a metering pump.

Subsequently, 201 g of a 10% aqueous sodium hydroxide solution was added over 1 hour, and 134 g of a 5% aqueous sodium hydroxide solution was similarly added over 2 hours.

After stirring for an additional hour, the precipitate was filtered through filter paper and washed with distilled water.

This was placed in a box-type dryer and dried at 100° C. for 24 hours, and then ground in a tabletop grinder to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that B16Qs
(O)-1)4. o (NO3)2.0 ・0.
81120, which matched the calculated value calculated from the raw materials used.

Further, as a result of X-ray diffraction, it was found to be a slightly crystallized substance with very low symmetry (Example 1).

100 g of bismuth nitrate pentahydrate and 40 g of mannitol were rubbed together in a mortar to make a viscous liquid, which was dissolved in 500 ml of distilled water.

Pour this into a 20% aqueous sodium hydroxide solution and
It was set to 1.

While cooling to 15°C, 4N sulfuric acid was gradually added and p
II was set as 10.

The precipitate was filtered through a 2-millimeter filter paper, washed thoroughly with water, placed in a box dryer, dried at 100°C for 24 hours, and pulverized with a tabletop pulverizer.
Hydrous bismuth oxide was obtained.

According to X-ray diffraction, this material was a highly crystalline material with a diffraction pattern different from that of Example 1 (Comparative Example 1).

90g of sodium carbonate and 30g of magnesium oxide in 5g of water
00g.

Next, 67 g of aluminum sulfate octahydrate was added to 500 g of distilled water.
An aqueous solution of 50 g was added to the above solution over a period of 1 hour.

After heating this at 90 to 100°C for 4 hours, the precipitate was removed! 12
It was filtered through filter paper and thoroughly washed with distilled water.

This was placed in a box-type dryer and dried at 100°C for 24 hours, and then dried in a tabletop grinder to produce hydrotalcite M g4sA.
12 (Or()13 CO-3H20 was obtained (Comparative Example 2).

10 each of the compounds obtained in Example 1, Comparative Example 1 and Comparative Example 2
g to O,IN sodium chloride aqueous solution 5001,
After stirring at 25° C. for 24 hours, the chloride ion concentration in the supernatant was measured, and the chloride ion exchange capacity of each substance was examined (Test 1).

Similarly, 10g of each compound was added to 0. After adding to 500 ml of IN sodium chloride aqueous solution and stirring at 85° C. for 1 hour, the chloride ion concentration in the supernatant was measured to examine the chloride ion exchange capacity of each substance (Test 2).

Similarly, 10 g of each compound was added to 100 ml of distilled water, and 2
The mixture was heated under reflux for 4 hours.

After cooling, the electrical conductivity in the supernatant was measured (Test 3)
.

The results of tests 1.2 and 3 are shown in Table 1.

Table 1 Example 2 and Example 3 236 g of bismuth oxide was dissolved in 764 g of 31.5% nitric acid.

Analysis of the concentration of bismuth nitrate in the solution revealed that Bi(N
It is 40.3% in terms of o), and free nitric acid is 4.90.
%Met.

A bismuth compound was obtained by carrying out the same reaction as in Example 1 except that the reaction temperature was controlled at 70°C.

When we analyzed the composition of this, we found that B1606(OH)4
．． 1 (No.) 1.9・0.71120.

The calculated value is B 1IiOs (OH)+, o
(N.

j) It is 2.0.

Furthermore, as a result of X-ray diffraction, the symmetry was higher than that of the compound of Example 1, and some of the peaks of hydrous bismuth oxide obtained in Comparative Example 1 were also observed (Example 2).

491 g of bismuth nitrate pentahydrate was added to 15.7% nitric acid 50%
It was melted to 9g.

When the concentration of bismuth nitrate in the solution was analyzed, it was found to be “3i (
No. 3 conversion: 40.0%, free nitric acid is 7.9
It was 5%.

A bismuth compound was obtained by carrying out the same reaction as in Example 1 except that the reaction temperature was controlled at 5°C.

When we analyzed the composition of this, we found that B1606(OH)3
．． 6 (No.) 2,4・1°11120.

The calculated value is B 1GOs (OH)4 (No
j) 2.

Further, as a result of X-ray diffraction, this compound was completely amorphous (Example 3).

Tests 1 to 3 were performed on the compounds obtained in Examples 2 and 3 in the same manner as in Example 1. The results are shown in Table 2.

Table 2 Example 4 177 g of bismuth oxide was dissolved in 823 g of 24.8% nitric acid.

Analysis of the concentration of bismuth nitrate in the solution revealed that Bi(N
It is 30.2% in terms of o), and free nitric acid is 5.9%.
Met.

While maintaining the reaction temperature at 50°C, 392 g of 25% sodium hydroxide aqueous solution was added to this solution for 20 minutes using a metering pump.
Added in portions.

Subsequently, 76 g of a 20% aqueous sodium hydroxide solution was added over 45 minutes, and 51 g of a 15% aqueous sodium hydroxide solution was added in the same manner over a period of 90 minutes.

The following procedure was carried out in the same manner as in the example to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that Bie O6
(OH), 5. + (NOi),,q'
o, 61120.

In addition, the calculated value is [3igOg (O old + g (No) L
J, and the value of X became larger than this.

Tests 1 to 3 were conducted on this compound in the same manner as in Example 1. The results are shown in Table 3.

Table 3 Example 5, Comparative Example 3, and Comparative Example 4 708 g of bismuth oxide was dissolved in 2292 g of 31.5% nitric acid.

Analysis of the concentration of bismuth nitrate in the solution revealed that Bi(N
40.1% in terms of o), free nitric acid is 5.05
%Met.

This liquid was divided into three equal parts, Example 5, Comparative Example 3 and Comparative Example 4.
In one case, 1057 g of a 10% aqueous potassium hydroxide solution was added to this solution over 90 minutes using a metering pump while maintaining the reaction temperature at 40°C.

Subsequently, 120 g of 10% potassium hydroxide aqueous solution
190 g of a 5% aqueous potassium hydroxide solution was added in the same manner over 4 hours.

After stirring for an additional hour, the precipitate was filtered through filter paper and washed with distilled water.

This was placed in a box-type dryer and dried at 120° C. for 15 hours, and then ground in a tabletop grinder to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that l3i60s
(OH)4.0 (No:l)z,o ・0.71
120, which agreed with the calculated value (Example 5).

To one of the bismuth nitrate solutions previously divided into three equal parts, 1057 g of a 15% potassium hydroxide aqueous solution was added over 90 minutes using a metering pump while maintaining the reaction temperature at 40°C.

Subsequently, 120 g of 10% potassium hydroxide aqueous solution
It was added in portions in the same manner.

After stirring for an additional hour, the precipitate was filtered through filter paper and washed with distilled water.

This was placed in a box-type dryer and dried at 120° C. for 15 hours, and then ground in a tabletop grinder to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that BiGOG
(011)3.0 (No:3)3. .・1
．． I H20 (Comparative Example 3).

To one of the bismuth nitrate solutions previously divided into three equal parts, 523 g of a 5% aqueous potassium hydroxide solution was added over 8 hours using a metering pump while maintaining the reaction temperature at 40°C.

After stirring for an additional hour, the precipitate was filtered through 11112 filter paper and washed with distilled water.

This was placed in a box-type dryer and dried at 120° C. for 15 hours, and then ground in a tabletop grinder to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that B16Os
(0■1), g, T (N Oko). , 3・0.
4H20 (Comparative Example 4).

Tests 1 to 3 were conducted on the compounds obtained in Example 5 and Comparative Examples 3 and 4 in the same manner as in Example 1.

The results are shown in Table 4.

Table 4 Example 6, Comparative Example 5 and Comparative Example 6 491 g of bismuth nitrate pentahydrate was added to 15.7% nitric acid 50
It was melted to 9g.

Analysis of the concentration of bismuth nitrate in the solution revealed that Bi(N
40.2% in terms of o), free nitric acid is 7.96
%Met.

While maintaining the reaction temperature at 30° C., 280 g of 20% ammonia water was added to this solution over 2 hours using a metering pump.

Subsequently, 87 g of 10% ammonia water was poured over 150 minutes, and 5
% ammonia water was added in the same manner over 5 hours.

After stirring for an additional 1 hour, the precipitate was filtered with (2) filter paper and washed with Fujidome water.

This was placed in a box-type dryer and dried at 100° C. for 24 hours, and then ground in a tabletop grinder to obtain a bismuth compound.

When we analyzed the composition of this compound, we found that 13i60e
(01-I), i, o (No:+)1. o
・0. 71120 (Example 6).

10.0g of the compound obtained in Example 6 as NaC1
After adding to N,N-dimethylformamide 11 containing 5 ppm (12100 ppm as chloride ions) and stirring at 30°C for 1 hour, the chloride ions in the supernatant were analyzed to determine the chloride ion removal rate. Ta.

Similar tests were conducted on the compounds obtained in Comparative Examples 1 and 2 (Comparative Examples 5.6).

These results are shown in Table 5.

Table 5 Example 7, Comparative Examples 7 to 9 6 g of the compound produced in Example 6, 75 parts of cresol novolac epoxy resin, 25 parts of brominated epoxy resin, 50 parts of phenolic resin and 150 parts of phased silica were melt-blended and heated at 170°C. It was heat cured for 20 minutes.

The cured product was pulverized, and 10 g of the product having a particle size of 100 MSO or less was placed in 100 ml of distilled water and heated at 151° C. for 100 hours.

After completion, the chloride ion concentration and bromide ion concentration in the supernatant liquid were measured (Example 7).

A similar test was conducted without adding the compound obtained in Example 6 (Comparative Example 7).

Separately, similar tests were conducted on the compounds obtained in Comparative Example 1 and Comparative Example 2 (Comparative Example 8.9).

The results of these tests are shown in Table 6.

Table 6 (3) Effects of the invention Invention (7) B is Os (011) x (
It is an @-x compound that has a large anion exchange capacity and exchange rate near neutrality, and has excellent water resistance and heat resistance, making it possible to capture anions that were previously difficult to capture near neutrality. It is used as an easy-to-perform inorganic anion exchanger and can be widely used in fields that use ion exchange and adsorption.

Claims (1)

[Claims] 1. Bi_6O_6(OH)χ(NO_3)_6_-_
A bismuth compound represented by the formula χ·nH_2O (3.5≦χ≦5.5, n is 0 or a positive number). 2, Bi_6O_6(OH)χ(NO_3)_6_-_
An inorganic anion exchanger containing a bismuth compound represented by the formula χ·nH_2O (3.5≦χ≦5.5, n is 0 or a positive number) as an active ingredient.