JP2935792B2 - Halogen ion adsorption method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to
For example, the present invention relates to a method for adsorbing halogen ions, which can remove fluorine ions and chlorine ions such as plaque-like teeth from the water to be treated.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Publication No. 58-6553, a method of removing the above-mentioned fluorine ions from the water to be treated containing a small amount of fluorine ions is known.

That is, in the above method, the phosphate water and calcium hydroxide are contained in the water to be treated, and the number of atoms of phosphorus (P) and calcium (Ca) including calcium (Ca) contained in the water to be treated. The mixture is added so that the ratio becomes 3: 5 or less, and the pH is adjusted to 8 to 9 to form hydroxyapatite in the water to be treated and stirred.

Thereafter, the water to be treated, in which the hydroxyapatite has been formed, is passed through the bone charcoal layer to continuously and continuously crystallize the hydroxyapatite crystals on the surface of the bone charcoal layer. Are captured by ion exchange, and the fluorine ions in the water to be treated are continuously removed.

[0005]

However, in the above-mentioned conventional method, fluorine ions can be trapped and removed, but the efficiency of trapping other halogen ions, such as chlorine ions, is low, so that the chlorine ion removal efficiency is low. For this reason, in the well water in an area where salt damage or the like is occurring, the chlorine ion concentration is high, and the above-described conventional method has a problem that it cannot be used for removing chlorine ions from the water to be treated such as the well water as described above. ing.

[0006]

According to the halogen ion adsorption method of the present invention, in order to solve the above-mentioned problems, water to be treated containing halogen ions is added to granules obtained by granulating amorphous calcium phosphate fine particles. By passing through, the halogen ions are adsorbed on the particulate matter to remove the halogen ions in the water to be treated.

The above amorphous calcium phosphate (amorphous
calcium phosphate (hereinafter abbreviated as ACP) A slurry containing fine particles is prepared by adding a water-soluble polymer dispersant, for example, ammonium triacrylate to a suspension of calcium hydroxide under stirring at 0.1 to 10% by weight. 0.1-3% by weight
After adding to obtain a mixed solution, the mixed solution under stirring is adjusted to pH 10 to 5 by dropwise addition of an aqueous phosphoric acid solution, thereby containing ACP fine particles having a particle size of about 1 μm or less.

The above-mentioned ACP fine particles are obtained from a pattern obtained by a powder X-ray diffraction method, based on calcium phosphate [Ca ₃ (PO ₄ ) ₂ .nH].
₂ O] and the pattern is broad, confirming that it is amorphous calcium phosphate. In addition, the ACP fine particles are considered to be electrostatically active since they contain water of crystallization, and because they are amorphous, they trap halogen ions such as chloride ions having a larger ion radius than fluorine ions. It can be considered that it can be adsorbed.

Further, in order for the granular material obtained by granulation to have a large specific surface area, it is desirable that the ACP fine particles of the slurry have a particle size of 1 μm or less. On the other hand, when the amount of ACP fine particles in the slurry is 90% by weight or more, the viscosity of the slurry becomes high, which makes the slurry unsuitable for granulation. In addition, the content of the ACP fine particles in the slurry is 1 to
By varying in the range of 90% by weight, the desired, for example 8
Granules having an average particle size of 200200 μm can be obtained.

The granulation method is not particularly limited as long as the obtained granules are porous and substantially spherical and can have a specific surface area of 10 m ² / g or more.
For example, a spray-drying granulation method can be used. Alternatively, a granulation method obtained by freeze-drying followed by pulverization, or a high-speed stirring type granulation method may be used.

Further, the granular material may be further granulated to be porous particles having a larger average particle size, for example, an average particle size of 0.2 to 40 mm. The use of such porous particles facilitates handling such as filling and taking out of the porous particles when used in a column or when used in a fluidized bed.

As a method for producing the above-mentioned porous particles, the above-mentioned granular material and a binder are kneaded, and the kneaded material is extruded (pelletizer), tumbling granulation (Malmerizer, Fuji Powder Co., Ltd.). ), A fluidized-bed granulation method (CF Granulex, manufactured by Freund Corporation), or a press molding method such as a rubber press, etc., and the molded product is heated at 450 to 800 ° C. in an oxidizing atmosphere. The porous particles are obtained by heating to remove the binder.

The shape of the porous particles is spherical, granular, cylindrical or the like, and the shape is not particularly limited. The above average particle size is indicated by the length of the obtained porous particles.

As an example of the method for producing the porous particles,
For example, when cylindrical porous particles are obtained, a mixture of a binder such as polyvinyl alcohol and a solvent such as water is kneaded with the above-mentioned granules so as to have a concentration of 0.1 to 20% by weight, and the kneaded product is extruded. A columnar granule is obtained by the granulation method. The granulated material has a diameter of 0.5 to 40 mm and a height of 0.5 to 40 mm
It is prepared so that

[0015] The granulated product is dried at 80-150 ° C.
After drying at 450 to 800 ° C. in an oxidizing atmosphere, the binder can be oxidized and gasified to be removed, and columnar porous particles composed of ACP fine particles can be obtained.

If the heating temperature is lower than 450 ° C., the respective granules are not adhered to each other by firing, so that the shape of the granules from which the binder has been removed cannot be maintained. On the other hand, if the heating temperature exceeds 800 ° C., the amorphous calcium phosphate constituting the granular material is crystallized, so that the excellent halogen ion adsorption ability of the amorphous calcium phosphate is deteriorated.

As another example of the method for producing the porous particles, when spherical porous particles having a large specific surface area are to be obtained, a mixed solution of a binder such as polyvinyl alcohol and water is used in an amount of 0.1 to 20% by weight based on the granular material. Kneaded so that
The kneaded material is extruded and granulated by a diameter of 0.5 to 40φ.
A cylindrical granulated material having a height of 0.5 to 40 mm in mm is obtained.

After the above-mentioned columnar granules are obtained by a rolling granulation method (rotation speed of a top plate, 300 to 650 rpm), spherical granules are obtained.
The spherical granulated product is dried at 80 to 150 ° C. in a dryer, and subsequently, the binder is oxidized and gasified and removed in an oxidizing atmosphere at 450 to 800 ° C. or lower to obtain spherical porous particles. Is obtained.

As the method for obtaining the target particle diameter of the spherical porous particles, two methods are separately considered. The first method is a method of extruding and granulating a circle larger than the target particle diameter. A method in which columnar granules are produced, and the columnar granules are shaved into spherical particles having a predetermined particle size. The second method is
A while spraying a binder on granules smaller than the target
This is a method in which CP fine particles are applied, the ACP fine particles are laminated on the surface of the granulated material, and the granulated material is made spherical. The spherical granules thus obtained are dried and heated in the same manner as described above to obtain spherical porous particles.

[0020]

【Example】

[Embodiment 1] The following will describe one embodiment of the present invention as Embodiment 1 with reference to FIGS. First, amorphous calcium phos
The method for producing a slurry containing particles will be described below. First, 0.5% by weight of ammonium triacrylate as a water-soluble polymer dispersant is added to a calcium hydroxide suspension under stirring. After obtaining a mixed solution, a phosphoric acid aqueous solution diluted with water 2 to 4 times is dropped to the mixed solution under stirring until the pH reaches around 11, and then diluted with water 5 to 8 times. The resulting phosphoric acid aqueous solution was added dropwise to adjust the mixed solution to pH 10 to 9, thereby obtaining a slurry containing ACP fine particles having a particle size of about 0.1 μm or less.

The above slurry was diluted with ion-exchanged water to prepare an ACP concentration of 20% by weight, and an ACP slurry 3 was obtained as shown in FIG. The ACP
The slurry 3 was supplied to a spray drier (L-8 manufactured by Okawara Kako Kikai Co., Ltd.) 5 by a metering pump 4.

The atomizer 6 of the spray drier 5 was rotated at a high speed to spray the ACP slurry 3 into a hot air stream for drying in the spray drier 5 and granulated and dried by a spray granulation method.

The substantially spherical ACP particles 7 obtained by granulation and drying were collected by a cyclone 8 to have a predetermined particle size of 8 to 100 μm. At this time, the ultrafine powder that could not be collected by the cyclone 8 was separately collected by a bag filter (not shown).

The operating conditions in the above spray-drying granulation were as follows. The supply amount of the ACP slurry 3 as a raw material by the metering pump 4 is 1 to 3 kg / h, and the temperature of the hot air heated by the electric heater 10 through the air filter 9 is such that the inlet temperature of the hot gas chamber 11 is 200-2
At 50 ° C., the outlet temperature at the discharge hole 12 connected to the cyclone 8 was controlled so as to always exceed 100 ° C., and the rotation speed of the atomizer 6 was set in the range of 10,000 to 37,000 rpm.

Further, using two types of spray dryers (FOC-20, OD-25G, FOC-25, OC-25 manufactured by Okawara Kako Kikai Co., Ltd.) obtained by scaling up the spray dryer 5,
ACP particles were prepared in the same manner as described above except that the slurry supply rate was 100 kg / hr. As a result, ACP particles similar to the ACP particles 7 obtained by the spray dryer 5 were obtained. The ACP particles thus obtained were also truly spherical.

The ACP particles 7 obtained in Example 1 were subjected to powder X-ray diffraction to
The ACP particles 7 were identified as calcium phosphate [Ca ₃ (PO ₄ ) ₂ .nH ₂ O], and the X-ray diffraction pattern was broad. From the results, it was found that the above calcium phosphate was amorphous.

Next, the ability of the ACP particles 7 to adsorb chlorine ions and bromine ions, which are halogen ions, was examined. First, 3 liters of ion-exchanged water is put into a 5 liter tank, and then the above-mentioned ACP particles 7
00 g was added to prepare an addition solution.

Then, while stirring the addition solution, the amount of chloride ion added to the ACP particles 7 in the addition solution was 10, 20, 30, 40, 50, 60, 70, 80, 90 mol%.
Thus, mixed ion solutions were prepared by adding the chloride ion solutions, respectively, and the mixed liquid solutions were stirred for 10 minutes. In addition, as the above-mentioned chloride ion solution, anhydrous ammonium chloride (NH ₄ Cl) is 10 (wt / vol%).
What was dissolved in ion-exchanged water so as to become an aqueous solution was used.

Thereafter, the respective ACP particles 7 having different added amounts of chloride ions as described above were collected by filtration, washed with ion-exchanged water, and dried at 120 ° C. for 24 hours.
The amount of chloride ions in each of the obtained ACP particles 7 was quantitatively analyzed by ion chromatography.

From the results of these analyses, analytical conversion values were calculated, each of which was converted to the amount of each chloride ion in the mixed addition solution. FIG. 2 is a graph showing the relationship between these results and the amount of each chlorine ion added. In addition, in the figure, the number attached to each black circle indicates the amount (mol%) of chloride ions added to the ACP particles 7, respectively.

Based on the above results, each analytical conversion value obtained is a straight line having a slope of 1 (the broken line in the figure) which is a theoretical value line when the added chloride ions are captured by the ACP particles 7 at 100%. Was almost on top. From this, it can be seen that almost 100% of the chloride ions in the mixed additive solution were captured by the ACP particles 7, adsorbed and removed from the mixed additive solution.

Further, X-ray diffraction was performed on each of the chloride ion-containing ACP particles prepared so that the added amount (mol%) of chloride ions to the ACP particles 7 was 60, 70, 80, 90, and 100, respectively. FIG. 3 shows the obtained X-ray diffraction patterns. The above chloride ion-containing ACP particles were calcined at 800 ° C. and used for X-ray diffraction.

Also in each of the above patterns, the peaks A and B indicating chloride ions increase as the chloride ion content increases, and the chloride ions in the mixed additive solution are almost trapped by the ACP particles 7. It can be seen that they were adsorbed and removed from the mixed additive solution.

Next, bromine ions in the ACP particles 7 (Br ^-) the adsorption capacity were examined in the same manner as described above chlorine ions. That is, the amount of bromine ions added to the ACP particles 7 in the additive solution was 1.6, 3.2, 4.8,
Bromine ion solutions were respectively added so as to be 6.4 and 8.0% by weight to prepare mixed additive solutions, and the mixed additive solutions were stirred for 10 minutes. In addition, as the bromine ion solution, anhydrous ammonium bromide (NH ₄ Br)
Was dissolved in ion-exchanged water to obtain a 10 (wt / vol%) aqueous solution.

Thereafter, each of the ACP particles 7 to which different amounts of bromine ions were added was collected by filtration, washed with ion-exchanged water, and dried at 120 ° C. for 24 hours.
The amount of bromine ions in each of the obtained ACP particles 7 was quantitatively analyzed by ion chromatography.

From the results of these analyses, analytical conversion values were calculated in terms of the amount of each bromine ion in the mixed addition solution. FIG. 4 is a graph showing the relationship between the results and the amounts of added bromine ions.

From the above results, it can be seen that the added bromine ion is 1
Each of the obtained analysis converted values (shown by a white circle in the figure) is compared with a straight line having a slope 1 (shown by a black circle in the figure), which is a theoretical value straight line when captured by the ACP particles 7. ) Were substantially parallel straight lines. This indicates that the bromine ions in the mixed additive solution were captured by the ACP particles 7, adsorbed and removed from the mixed additive solution.

Embodiment 2 Another embodiment of the present invention will be described as Embodiment 2. First, 2.5 kg of the ACP particles 7 of Embodiment 1 and a binder are mixed, and the mixture is extruded. Granulator (made by Fuji Paudal: PV Pellettor PV-2)
(0 type) to obtain a columnar granule by extrusion granulation. As the binder, a solution in which polyvinyl alcohol was dissolved in water so as to be 2% by weight was used.

This granulated product was 2 mm in diameter and 5 mm in height. The granulated product is dried in a dryer at 100 ° C. for 6 hours, and then heated in air at 500 ° C. for 3 hours to oxidize and gasify the polyvinyl alcohol of the binder to remove the granulated product. Columnar porous AC of almost the same shape as
P particles were obtained.

When the amounts of chloride ions and bromine ions adsorbed on the porous ACP particles were examined in the same manner as in Example 1, the results were the same as those in Example 1. Therefore, the figures showing the results are omitted.

Third Embodiment Still another embodiment of the present invention will be described as a third embodiment. First, the AC of the first embodiment will be described.
2.5 kg of P particles 7 were mixed with the binder in Example 2 above, and the mixture was extruded and extruded with a granulator (Fuji Paudal Co., Ltd., PV Pellettor PV-20 type) to form a columnar granule. I got something.

This columnar granule has a diameter of 2 mm and a height of 6 mm.
mm. This columnar granule was subjected to rolling granulation (Malmerizer, manufactured by Fuji Paudal Co., Ltd.) to obtain a spherical granule having a diameter of 5 mm by rolling granulation (rotational speed of the top plate 300 to 650 rpm).

This spherical granulated product was dried at 100 ° C. for 6 hours in a drier, and then heated in air at 500 ° C. for 3 hours to oxidize and gasify the polyvinyl alcohol as the binder to remove the binder. Spherical porous ACP particles having substantially the same shape as the spherical granulated product were obtained.

The spherical porous ACP particles were examined for the amount of chloride ion and bromine ion adsorbed in the same manner as in Example 1, and the results were the same as in Example 1. Therefore, the figures showing the results are omitted.

The porous ACP particles of Examples 2 to 3 have excellent halogen ion-adsorbing ability as in Example 1 and have a large particle size. The clogging is avoided, and furthermore, it is easy to take out from the column or the like, and handling becomes easy.

As described above, the porous ACP particles and A
In the method of adsorbing halogen ions using the CP particles 7, since the halogen ions can be efficiently adsorbed and removed from the water to be treated such as well water, the chlorine ions can be efficiently removed from the well water in an area where salt damage or the like has occurred. As a result, the method can be suitably used to purify the water to be treated such as the well water into drinking water.

Further, since fluorine ions can be removed, it can be used for removing the fluorine ions from tap water having a high fluorine ion concentration in order to prevent dental diseases such as mottled teeth. Further, similarly to the above-mentioned chlorine ions and bromine ions, the present invention can be applied to the removal of iodine ions and the like.

The ACP particles 7 in each of the above embodiments were used.
Further, the porous ACP particles are restored by heating them to about 500 ° C. and passing water vapor so that the adsorbed halogen ions such as chloride ions are replaced with hydroxyl ions.

Thus, the ACP particles 7 and the porous ACP particles adsorbing the halogen ions of the chloride ions are replaced with the hydroxyl ions by the above-mentioned restoration method, and the ACP particles 7 and the porous ACP particles are replaced. Can be used repeatedly.

[0050]

As described above, the method for adsorbing halogen ions according to the present invention is characterized in that the water to be treated containing halogen ions is passed through a granular material obtained by granulating fine particles of amorphous calcium phosphate. To remove the halogen ions in the water to be treated.

Therefore, in the above method, the use of amorphous calcium phosphate allows efficient adsorption of halogen ions, especially chloride ions, and uses granules obtained by granulating amorphous calcium phosphate. The specific surface area of the body can be increased, and the ability to adsorb the halogen ions can be enhanced.

As a result, in the above method, since the halogen ions are contained in a high concentration, the halogen ions can be efficiently removed from the water to be treated, such as well water, which is unsuitable for beverages. The advantage is that it can be suitably used for such processing.

[Brief description of the drawings]

FIG. 1 shows an AC used in the halogen ion adsorption method of the present invention.
It is a schematic diagram of the spray granulator of the granulation method of P particle.

FIG. 2 is a graph showing the chlorine ion adsorption capacity of the ACP particles.

FIG. 3 is a graph showing an X-ray diffraction pattern of each of the ACP particles adsorbing chloride ions.

FIG. 4 is a graph showing the bromine ion adsorption capacity of the ACP particles.

[Explanation of symbols]

 7 ACP particles

Claims (1)

(57) [Claims] 1. A method comprising the steps of: passing water to be treated containing halogen ions through a granular material obtained by granulating fine particles of amorphous calcium phosphate; adsorbing said halogen ions to said granular material; A halogen ion adsorption method comprising removing ions.