JP3718517B1 - Anion adsorbing carbon material and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anion adsorbing carbon material which is inexpensive, environmentally friendly and excellent in anion adsorption property, and a method for producing the same.
A raw material 2 made of a plant is brought into contact with a solution 3 containing a metal chloride and then carbonized, and the metal compound is contained in the carbide.
[Selection] Figure 1

Description

  The present invention relates to an anion-adsorbing carbon material that adsorbs anions such as nitrate ions and fluoride ions, and a method for producing the same.

  Water and soil contamination by heavy metals, pesticides and organochlorine compounds are problematic as they destroy the environment. These harmful substances can be adsorbed and removed by adsorbents such as activated carbon and zeolite, but nitrate nitrogen or nitrite nitrogen, fluorine, arsenic, cyanide, etc. present in the form of anions are difficult to treat with adsorbents. is the current situation.

  In other words, nitrate nitrogen and nitrite nitrogen are contained in fertilizers used in tea fields, golf course turf, and the like, and contribute to groundwater contamination, which is currently a major problem. This is because nitrate ions and nitrite ions have a negative charge and do not form a sparingly soluble salt by combining with other chemical substances, so that they are most easily leached from the negatively charged soil. And measures against the above problems are necessary. For example, there are restrictions such as the need for anaerobic conditions in microbial treatment using denitrifying bacteria to remove nitrate ions and nitrite ions, etc. The method is the same and no effective countermeasure has been found. In addition, recently, nitrate nitrogen and nitrite nitrogen have been suspected of being environmental hormones.

  Fluorine is contained in wastewater from semiconductors, glass, plating plants, etc., and fluorine in factory effluent is removed by adding calcium compounds as calcium fluoride. It is necessary and expensive to install an adsorption tower using anion exchange resin. In addition, if the environmental standard is 0.8 mg / L or less, an expensive dedicated anion exchange resin is required. In addition, expensive anion exchange resins are also required for the treatment of arsenic and cyanide contained in factory wastewater and groundwater.

As described above, there is no inexpensive material that adsorbs the anions such as nitrate ions at present, and therefore, contamination by these anions tends to spread and is once contaminated by the anions. Then, a great cost is required for the repair.
Japanese Patent Laid-Open No. 10-165824

  Therefore, there is a need for an anion adsorption material that is inexpensive and environmentally friendly. Charcoal, which is a representative porous material together with activated carbon, is widely used as a humidity control material, river purification, and soil improvement material. For example, it is used to remove chlorine-based gases and sulfur oxides in exhaust gas. This, like activated carbon, uses only the adsorption characteristics due to the fine pores inside the porous carbon material, but also nitrate nitrogen or nitrite nitrogen existing in the form of anion, fluorine, arsenic, cyanide Almost no adsorption.

Accordingly, the present invention intensively studied, before carbonizing a raw material consisting of plants, a solution containing a pre-metal chlorides in the raw materials, for example the CaCl ₂ in the raw material by contacting a solution containing CaCl ₂ If the raw material into which the CaCl ₂ was introduced was carbonized after introduction, the carbonized material obtained thereby was found to have excellent anion adsorption performance.

  The present invention has been made in consideration of the above-described matters, and an object of the present invention is to provide an anion-adsorbing carbon material that is inexpensive, environmentally friendly, and excellent in anion adsorptivity, and a method for producing the same.

In order to achieve the above object, the method for producing an anion adsorbing carbon material of the present invention produces an anion adsorbing carbon material that adsorbs an anion by ion exchange with a chloride ion of a metal chloride contained in a carbide. In this method, the raw material comprising a plant is brought into contact with a solution containing a metal chloride, followed by carbonization, and the carbide is contained in the carbide (claim 1). Since the chloride ion of the metal chloride contained in the carbide develops anion exchange ability, the carbide functions as an anion-adsorbing carbon material. In addition, as a method of bringing a solution containing a metal chloride into contact with the plant material, the solution can be dropped, applied, sprayed, sprayed, etc., but it is most preferable to immerse the material in the solution. Efficient.

According to the method for producing the anion-adsorbing carbon material, the plant material is immersed in a solution containing CaCl ₂ as a metal chloride, and Ca ions and Cl ions are introduced into the material, and then the CaCl ₂ is introduced. CaCl ₂ -introduced carbon obtained by carbonizing the introduced material has excellent anion adsorption ability.

That is, for example, as shown in FIG. 5 (A), when the wood chips 2 as a raw material is immersed in CaCl ₂ solution 3 is brought into contact with the CaCl ₂ solution 3, the Ca ions and Cl ions in CaCl ₂ solution 3 When introduced into the wood chip 2, a CaCl ₂ introduction chip 5 is obtained as shown in FIG. This is because the CaCl ₂ solution 3 soaks into the tissue in the wood chip 2, particularly the passage tissue, as shown in FIG. As the concentration of the CaCl ₂ solution 3 used in the pretreatment of the raw material (contact treatment), CaCl ₂ 0.1 wt% to 50 wt% by weight, and cost more preferably 1 wt% to 20 wt%. If the amount is less than 0.1% by weight, a high anion adsorption ability is not expressed, and if it exceeds 50% by weight, the anion adsorption ability is not improved.

Subsequently, when the CaCl ₂ introduction chip 5 is carbonized as shown in FIG. 6A, the carbon material 1 is obtained as shown in FIG. In this carbonization process, organic substances in the CaCl ₂ introduction chip 5 are decomposed by heat, and simultaneously, Cl ions and Ca ions are deposited on the surface of the fine pore wall of the CaCl ₂ introduction chip 5. At this time, as shown in FIG. 5B, Cl ions and Ca ions are precipitated in a fine and highly dispersed state on the surface of the fine pore wall of the CaCl ₂ introduction chip 5, and many functional groups are formed at every corner of the fine pore wall. Pull out from. As a result, as shown in FIG. 6C, it is considered that Cl ions are bonded to a large number of functional groups extracted on the surface of the microporous wall via metal ions (in this case, Ca ions) or directly. It is done.

Also, a method for producing an anion-adsorbing carbon material that adsorbs anions by ion exchange of metal chlorides contained in carbides with chloride ions , comprising a plant in contact with a solution containing metal chlorides The raw material may be carbonized, and the metal chloride may be contained in the carbide (claim 2). That is, if a raw material made of a plant previously brought into contact with a solution containing a metal chloride is prepared, an anion-adsorbing carbon material similar to that of the invention according to claim 1 can be obtained simply by carbonizing it.

  In addition, as content of the said metal chloride, it is desirable to contain 2%-25% of metal chloride couple | bonded in a carbide | carbonized_material as ash (Claim 3). The metal compound bonded in the carbide is a metal chloride except for the metal chloride simply adhered in the carbide, and since it is bonded in the carbide, it does not dissolve after washing with water or acid. The residual metal chloride. If it is less than 2%, the anion adsorption ability is inferior, and even if it exceeds 25%, the anion adsorption ability tends not to be improved.

  Furthermore, in the invention which concerns on Claims 1-3, it is preferable to make water and / or an acid contact the said carbide | carbonized_material (Invention 4). In addition, as a method of bringing water and / or acid into contact with the carbide, water and / or acid can be dropped, applied, sprayed, sprayed, etc., but the carbide is immersed in water and / or acid. Is the most efficient.

Here, the reason why it is preferable to contact the carbide with water and / or an acid is considered as follows. That is, the carbon material (CaCl ₂ charcoal) 1 obtained as shown in FIGS. 5 and 6 is immersed (contacted) in an acid such as hydrochloric acid 13 or sulfuric acid as shown in FIG. 7A. Then, excess metal chloride crystals adhering to the carbon material 1 are removed. In addition, when hydrochloric acid 13 is used as the acid, Cl ions bonded to the functional group of the carbon material 1 newly increase, and the state changes from FIG. 7B to FIG. 7C. Therefore, the anion adsorption capacity of the produced anion adsorption carbon material is preferably increased. Even when the carbide is brought into contact with water instead of acid such as hydrochloric acid 13, excess metal chloride crystals adhering to the carbon material 1 are removed, and the anion adsorption ability can be enhanced.

  In addition, as a raw material in the invention which concerns on Claims 1-4, what is sufficient as long as it is a plant body, It consists of 1 or more types of a natural fiber and a woody material, and the thing in which a carbide | carbonized_material has a fine hole is preferable, for example, thinning All woody materials such as timber, felled wood and waste wood, and natural fibers such as hemp can be mentioned. In particular, it is preferable to use, as the raw material, a wood chip in which coniferous trees such as birch and cedar having high water absorption are chipped to a size of, for example, 50 mm or less. In addition to the wood chips, agricultural waste such as bamboo, sawdust, rice husk, coconut, areca, jute, cocoon, mandarin orange and apple peel, mandarin orange and apple pomace may be used. Moreover, the part which has a passage tissue (a road pipe, a temporary path pipe, or a master pipe) in a plant body is especially preferable.

  And in any said invention, it is preferable that the carbonization temperature of the said raw material is 400 to 1000 degreeC (Claim 5). This is because when the carbonization temperature is lower than 400 ° C., the fine pores are not developed and the performance as an adsorbent is inferior, and when the temperature exceeds 1000 ° C., the carbonization proceeds excessively, so that the adsorption characteristics cannot be obtained. . The carbonization temperature is more preferably 500 ° C to 900 ° C, and most preferably about 600 ° C to 800 ° C.

The anion adsorbing carbon material of this invention is characterized by comprising manufactured by the manufacturing method of an anion adsorbing carbon material according to any one of claims 1-5 (claim 6).

Further, the anion adsorbing carbon material of the present invention removes the adsorbed anion from the anion adsorbing carbon material according to claim 6 adsorbing the anion, and ion exchange with the next anion to be adsorbed. An anion capable of being replaced by the removed anion may be bonded (Claim 7) . Here, the anion that can be adsorbed by the anion-adsorbing carbon material of the present invention is an anion that can be ion-exchanged with the anion previously bonded to the surface of the microporous wall of the carbon material. An anion other than the anion previously bonded to the functional group on the surface of the microporous wall via a metal ion or directly.

In the inventions according to claims 1 to 6, an anion adsorbing carbon material having anion adsorption characteristics equivalent to or better than an anion exchange resin can be obtained. Furthermore, the anion-adsorbing carbon material is mainly made of plant materials and is environmentally friendly.

Moreover, in the invention which concerns on Claim 7, the anion adsorption | suction carbon material which can be repeatedly recycled is obtained.

  1 to 8 show an embodiment of the present invention. FIG. 1 schematically shows an example of an apparatus for producing an anion adsorbing carbon material (hereinafter referred to as carbon material) 1 according to an embodiment of the present invention. In this figure, 2 is a raw material plant, In this embodiment, it is a wood chip. The wood chip 2 is formed by chipping a softwood such as a ridge or a cedar having high water absorption into an appropriate size of 50 mm or less.

Then, the wood chip 2 is sent to a treatment tank 4 containing a metal chloride solution 3 (CaCl ₂ solution in this embodiment) having an appropriate concentration, and the metal chloride (with respect to the wood chip 2 (in this treatment tank 4) ( In this embodiment, CaCl ₂ ) is introduced to form the metal chloride introduction tip 5. Reference numeral 6 denotes a stirring blade provided in the processing tank 4, which is rotationally driven by a motor (not shown) and is used when stirring the liquid or the like in the processing tank 4. Here, in order to improve the anion adsorption ability, it is preferable to add Ca (OH) ₂ slightly to the metal chloride solution.

  The metal chloride introduction chip 5 obtained as described above is dried by the dryer 7 and then sent to the carbonization furnace 8 to be carbonized. The dryer 7 is configured to use the exhaust heat discharged from the carbonization furnace 8 for the drying process.

  A carbonization furnace body 10 heated by an appropriate heat source 9 is accommodated in the carbonization furnace 8. The metal chloride introduction chip 5 is supplied into the carbonization furnace main body 10 through the introduction part 11 and carbonized by heating at an appropriate temperature (described later) and an appropriate time (described later). It is discharged from the discharge unit 12 to the outside of the carbonization furnace main body 10.

  Thereafter, the carbon material 1 is sent to a treatment tank 14 containing water or an HCl solution (hydrochloric acid) 13, and the contact (immersion) treatment of the carbon material 1 with respect to the water or the HCl solution 13 is performed in the treatment tank 14. . Reference numeral 15 denotes an agitation blade provided in the processing tank 14, which is rotationally driven by a motor (not shown), and is used when the liquid in the processing tank 14 is agitated. After the contact treatment with the acid, the contact treatment with water may be performed, and vice versa.

  Subsequently, the carbon material 1 is sent to a dryer 16 and dried, and then formed into particles (pellets) 1a having a proper diameter or finer powder 1b. The dryer 16 is configured to use the exhaust heat discharged from the carbonization furnace 8 for the drying process.

  2A shows the carbon material 1 formed in a chip shape having a length of about 10 mm, and FIG. 2B shows the chip-shaped carbon material 1 in a particle having an appropriate diameter ( An example of forming the pellets 1a is shown.

  Next, an example of a procedure for obtaining the carbon material 1 from the raw material plant 2 using the apparatus shown in FIG. 1 will be described in detail with reference to FIGS. 1 and 3. First, a wood chip 2 in which conifers such as birch and cedar are chipped to an appropriate size of 10 mm or less is prepared (step S1).

Subsequently, the wood chip 2 is immersed in the CaCl ₂ solution 3 adjusted to 1 to 20% by weight in the treatment tank 4 for 3 hours or more, for example. It is preferable to rotate the stirring blade 6 during the immersion of the wood chip 2. As a result, the CaCl ₂ solution 3 can permeate into the wood chip 2, and the metal chloride introduction chip 5 in which Ca ions and Cl ions are introduced into the wood chip 2 is obtained (step S2).

  Then, the metal chloride introduction chip 5 is sent to the dryer 7 and dried (Step S3).

  Thereafter, the wood chip 2 is supplied to the carbonization furnace body 10 of the carbonization furnace 8 and heated and carbonized for about 1 hour in a temperature range of 400 ° C. to 1000 ° C. (700 ° C. in this embodiment) (step) S4). Thereby, the carbon material 1 is obtained.

The carbon material 1 is supplied to the treatment tank 14 and immersed in the HCl solution 13 adjusted to 0.01 mol / L to 11 mol / L (for example, 5 mol / L) in the treatment tank 14 (step S5). In this case, it is preferable to rotate the stirring blade 15, whereby it is possible to remove excess metal chloride (CaCl ₂ ) crystals remaining in the carbon material 1 and to further add chloride ions. The desired carbon material 1 can be obtained.

  And the carbon material 1 after the said immersion process is generally dried in the dryer 16 (step S6). In this case, the carbon material 1 may be sent to the dryer 16 as it is, but may be neutralized by immersing it in an appropriate alkaline solution, or may be washed with water after the neutralization. In addition, when using the carbon material 1 in a wet state, a drying process may not be performed.

  The carbon material 1 after the drying treatment can be used in the form of chips, but in this embodiment, an appropriate diameter machine (pellet) 1a or finer powder 1b is used with an appropriate processing machine. (Step S7). The carbon material 1 may be used in a state of being attached to a non-woven fabric, for example, in addition to being used alone.

  In addition, the said carbon material 1 is not restricted to what the said step S1 to step S7 is performed within the same factory. For example, when it is manufactured up to a certain step among the above steps S1 to S7 in other factories or the like, the carbon material 1 may be manufactured starting from an intermediate step.

  Since the carbon material 1 adsorbs nitrate nitrogen and nitrite nitrogen, it can be considered to be used for the following three applications, for example. First, the carbon material 1 can be used for water purification as shown in FIG. In this case, it also functions as a microbial carrier. Moreover, the carbon material 1 can be used for the prevention of the contamination by livestock as shown in FIG. 4 (B). Specifically, it can be applied to areas where manure is likely to flow out, such as livestock manure deposits and composting facilities. Furthermore, as shown in FIG. 4C, the carbon material 1 can be used for agriculture to prevent excessive fertilization contamination. That is, it is possible to adsorb nitrogen that has not been used by plants due to excessive fertilization, and the subsequent carbon material 1 can also be used as a slow-acting fertilizer. In addition, especially in the event of a fire, nitrogen pollution is severe, such as the application of a large amount of nitrogen fertilizer and amino acids, and application to such areas is also possible.

  Further, since the carbon material 1 adsorbs fluorine, it can be used for waste water (waste water) treatment as shown in FIG. Specifically, it can be applied to a final processing facility provided in a semiconductor factory, a glass factory, a plating factory or the like where cleaning with hydrofluoric acid is performed.

The present invention is not limited to the above-described embodiment, and can be implemented with various modifications. For example, in the above embodiment, as the metal chloride, CaCl _{2 from} which the highest-performance anion-adsorbing carbon material is obtained is exemplified, but BaCl ₂ , MnCl _2, or the like may be used.

  Moreover, in the said embodiment, although the contact process with respect to the HCl solution 13 of the carbon material 1 is performed in the processing tank 14, it may replace with the HCl solution 13 and water may be used. In this case, chloride ions are not added, and only the excess metal chloride crystals remaining in the carbon material 1 are removed.

  Further, in the above embodiment, the metal chloride introduction chip 5 is carbonized in the carbonization furnace 8 to obtain the carbon material 1 and then sent to the treatment tank 14, but not sent to the treatment tank 14. May be. In this case, since it is not necessary to send the carbon material 1 to the dryer 16, the manufacturing method of the carbon material 1 is one in which the steps S5 and S6 are omitted. Moreover, in this case, as a manufacturing method of the carbon material 1, you may complete | finish by step S1-S4, and you may perform step S7 after that.

  Next, a test carried out for examining the adsorption performance of nitrate nitrogen and nitrite nitrogen of the carbon material 1 will be described. The test method and test results for the adsorption performance of nitrate nitrogen and nitrite nitrogen will be described as follows.

First, two sets of 200 mg each of seven samples (1) to (7) shown below were prepared. That is,
(1) Charcoal obtained by heating and carbonizing wood chip 2 at 700 ° C. for 1 hour (2) Heating and carbonizing wood chip 2 at 700 ° C. for 1 hour, and then dipping in 1 mol / L FeCl ₃ solution Iron chloride charcoal obtained by washing with water (3) Anion exchange resin (4) BaCl ₂ charcoal obtained by dipping the wood chip 2 in a 10% by weight BaCl ₂ solution, followed by heating at 700 ° C. for 1 hour for carbonization (5) The wood chip 2 is immersed in a 10 wt% BaCl ₂ solution, heated at 700 ° C. for 1 hour to be carbonized, and then immersed in a 5 mol / L HCl solution to obtain an HCl-treated BaCl ₂ charcoal ( 6) CaCl ₂ charcoal obtained by dipping the wood chip 2 in a 10 wt% CaCl ₂ solution and then carbonizing it by heating at 700 ° C. for 1 hour. (7) The wood chip 2 was dipped in a 10 wt% CaCl ₂ solution. After 1 hour at 700 ° C Two sets of a total of seven samples of HCl-treated CaCl ₂ charcoal obtained by heating and carbonizing and then dipping in a 5 mol / L HCl solution were prepared. The samples (4) to (7) correspond to the carbon material 1, and the samples (1) to (3) are for comparison with the carbon material 1.

  Then, each sample of one set is individually put into 50 mL (first standard solution) of a nitrate nitrogen solution having a nitrate nitrogen concentration of 50 mg / L (50 ppm), and each sample of the other set is The nitrite nitrogen concentration was individually added to 50 mL (second standard solution) of nitrite nitrogen solution having a concentration of 50 mg / L (50 ppm). Then, after shaking for 10 hours under the conditions of 200 rpm and 20 ° C., the concentration of nitrate nitrogen in the first standard solution and the concentration of nitrite nitrogen in the second standard solution were measured, respectively. The amount of adsorbed nitrogen and nitrite nitrogen was calculated.

FIG. 9 shows a comparison result of nitrate nitrogen adsorption ability and nitrite nitrogen adsorption ability of each sample obtained by the above test. In this figure, the amount of nitrate nitrogen and nitrite nitrogen adsorption of each sample is shown as a pair of bar graphs. The left bar graph shows the nitrate nitrogen adsorption amount, and the right bar graph shows the nitrite nitrogen adsorption amount. ing. From the results shown in this figure, it can be seen that all the samples of the present invention have high nitrate nitrogen adsorption ability and nitrite nitrogen adsorption ability. Furthermore, the adsorption amounts of nitrate nitrogen and nitrite nitrogen of (4) BaCl ₂ charcoal and (5) HCl-treated BaCl ₂ charcoal were compared, and (6) CaCl ₂ charcoal and (7) HCl adsorbed. In order to further increase the nitrate nitrogen / nitrite nitrogen adsorption capacity of the carbon material 1 by comparing the adsorption amounts of nitrate nitrogen and nitrite nitrogen of the treated CaCl ₂ charcoal, the carbon material 1 is added to the HCl solution. It can be seen that it is better to perform a dipping treatment (HCl treatment). However, the carbon material 1 having sufficiently high nitrate nitrogen / nitrite nitrogen adsorption ability can be obtained without performing HCl treatment. In this case, the cost is low because the contact treatment of the HCl solution is not performed. The carbon material 1 can be manufactured.

Here, the carbon material 1 adsorbs nitrate ions, for example, when the carbon material (CaCl ₂ charcoal) 1 is immersed in the nitric acid solution 17 as shown in FIG. Cl ions (see (B) in the same figure) directly bonded to the group via Ca ions or NO ₃ ions in the nitric acid solution 17 are exchanged (see (C) in the same figure), and the NO ₃ ions are converted into the carbon material 1. It is thought that this is because it is adsorbed on the surface (see FIG. 4D).

Further, FIG. 8E shows that the carbon material 1 that has adsorbed NO ₃ ions to the state shown in FIG. 8D is converted into a high-concentration chloride solution (for example, a metal chloride solution of KCl or NaCl, or The state after being immersed in HCl solution) is shown. That is, NO ₃ ions adsorbed on the carbon material 1 are exchanged with Cl ions by the chloride solution, whereby the carbon material 1 is regenerated, and anions such as NO ₃ ions can be adsorbed. That is, the carbon material 1 of the present invention is not limited to a material that is always newly obtained by the above production method, but is obtained by the production method and adsorbed from the carbon material 1 that adsorbs anions (for example, NO ₃ ions). In addition to removing ions (NO ₃ ions), the anions (NO ions in this embodiment) capable of ion exchange with the next anions (for example, NO ₃ ions) to be adsorbed (NO ions in this embodiment) are removed. What was obtained by combining instead of ₃ ion) (namely, what was regenerated) may be used. When sulfuric acid is used instead of the chloride solution, NO ₃ ions are ion-exchanged with SO ₄ ions instead of the Cl ions.

Next, the test conducted to examine the influence of the concentration of the metal chloride solution (CaCl ₂ solution) 3 in which the wood chip 2 is immersed in the above step S2 on the anion adsorption ability of the carbon material 1 after production will be described. . In the above test, the carbon material 1 obtained by immersing the wood chip 2 in the CaCl ₂ solution 3 and then carbonizing it by heating at 700 ° C. for 1 hour and washing it with water, the concentration of nitrate nitrogen is 50 mg / L (50 ppm). Was added to 50 mL (standard solution) of nitrate nitrogen solution, and the adsorption ability of nitrate nitrogen of the carbon material 1 was examined. As the CaCl ₂ solution 3, the concentration was 1% by weight, 3% by weight, 5% by weight. %, 7%, 10%, 12%, 14%, 17% and 20% by weight were used. For comparison, the adsorption of nitrate nitrogen of the carbon material 1 obtained by immersing the wood chip 2 in a 10 wt% CaCl ₂ solution 3 and carbonizing it by heating at 700 ° C. for 1 hour and treating with HCl. I also examined Noh. The results of the above test are shown in FIG.

As is apparent from the results shown in FIG. 10, the anion adsorption capacity of the carbon material 1 does not increase in proportion to the concentration of the CaCl ₂ solution, and is about 10% by weight from the viewpoint of cost. Most preferred. In addition, the results shown in FIG. 10 also show that the carbon material 1 should be treated with HCl in order to further enhance the anion adsorption ability of the carbon material 1.

  Next, a regeneration test performed to regenerate the carbon material 1 used for adsorption of nitrate nitrogen with a KCl (or NaCl) solution and examine the nitrate nitrogen adsorption ability of the regenerated carbon material 1 will be described.

First, as the carbon material 1, 200 mg of CaCl ₂ charcoal obtained by immersing the wood chip 2 in a 10 wt% CaCl ₂ solution and heating and carbonizing at 700 ° C. for 1 hour was prepared. Then, this CaCl ₂ charcoal was put into 50 mL (standard solution) of a nitrate nitrogen solution having a nitrate nitrogen concentration of 50 mg / L (50 ppm), shaken at 200 rpm and 20 ° C. for 10 hours, The concentration of nitrate nitrogen in the standard solution was measured, and the amount of nitrate nitrogen adsorbed by the CaCl ₂ charcoal was calculated (first time).

Subsequently, the CaCl ₂ charcoal was washed with a 1 mol / L KCl (or NaCl) solution and further regenerated by washing with water. Thereafter, the regenerated CaCl ₂ charcoal is added to a newly prepared standard solution (that is, a nitrate nitrogen solution 50 mL having a nitrate nitrogen concentration of 50 mg / L) and shaken for 10 hours under the conditions of 200 rpm and 20 ° C. Thereafter, the concentration of nitrate nitrogen in the standard solution was measured, and the amount of nitrate nitrogen adsorbed by the CaCl ₂ charcoal was calculated. Then, the process from the reproduction of the CaCl ₂ charcoal up to the calculation of the amount of adsorbed nitrate nitrogen was carried out three times (reproducing first time - third time).

As a result of the regeneration test, that is, the adsorption amount of nitrate nitrogen by CaCl ₂ charcoal is
First time: 9.5mg / g
The first regeneration ... 9.0mg / g
Second regeneration: 9.1 mg / g
The third regeneration ... 8.8mg / g
Met. From the above, it was confirmed that the carbon material 1 (CaCl ₂ charcoal) used for adsorption of nitrate nitrogen was regenerated by washing with a concentrated KCl (or NaCl) solution and further with water. This is because the nitrate nitrogen is removed from the CaCl ₂ charcoal by washing the CaCl ₂ charcoal having adsorbed nitrate nitrogen with a KCl (or NaCl) solution and then washing with water. This is thought to be because Cl ^- is bonded to a functional group. From the results of the regeneration test, carbon material 1 (CaCl ₂ charcoal) can be used multiple times for adsorption of nitrate nitrogen if it is regenerated by washing with KCl (or NaCl) solution and washing with water. It was also confirmed that it could be done. Even when the carbon material 1 (CaCl ₂ charcoal) is used for adsorption of nitrite nitrogen, the principle of regeneration is the same.

Next, as the carbon material 1, the wood chip 2 was immersed in a 10% by weight CaCl ₂ solution, heated at 700 ° C. for 1 hour to be carbonized, and then immersed in a 5 mol / L HCl solution. using the processing CaCl ₂ charcoal, this HCl processed CaCl ₂ charcoal shows the results of similarly regeneration test as described above.

As a result of the regeneration test, that is, the adsorption amount of nitrate nitrogen by the HCl-treated CaCl ₂ charcoal,
First time ... 11.0mg / g
The first regeneration ... 11.0mg / g
Second regeneration: 10.8mg / g
The third regeneration ... 10.8mg / g
Met. From the above, carbon material 1 (HCl-treated CaCl ₂ charcoal) obtained by immersing in an HCl solution after carbonization is also washed with a concentrated KCl (or NaCl) solution after being used for adsorption of nitrate nitrogen, Regeneration was confirmed by washing with water. Further, the nitrate nitrogen adsorption ability of the HCl-treated CaCl ₂ charcoal improved by the immersion treatment in the HCl solution is obtained by repeatedly regenerating the HCl-treated CaCl ₂ charcoal by washing with KCl (or NaCl) solution and washing with water. Has also been confirmed to remain (still improved).

  Next, a test carried out for examining the fluoride ion adsorption performance of the carbon material 1 will be described. First, in order to perform this test, 50 mg each of a total of seven samples (1) to (7) used in the above-described adsorption performance test for nitrate nitrogen and nitrite nitrogen were prepared. Each sample was individually added to 50 mL (standard solution) of a solution having a fluoride ion concentration of 50 mg / L (50 ppm), shaken at 200 rpm and 20 ° C. for 10 hours, and then subjected to the fluoride in the standard solution. The concentration of fluoride ion was measured, and the amount of fluoride ion adsorption by each sample was calculated.

FIG. 11 shows a comparison result of fluoride ion adsorption ability of each sample obtained by the above test. From the results shown in this figure, it can be seen that all the samples of the present invention have high fluoride ion adsorption ability. Furthermore, the adsorption amounts of fluoride ions of (4) BaCl ₂ charcoal and (5) HCl-treated BaCl ₂ charcoal were compared, and (6) CaCl ₂ charcoal and (7) HCl-treated CaCl ₂ charcoal were compared. By comparing the adsorption amounts of fluoride ions, it is understood that it is better to perform a treatment (HCl treatment) in which the carbon material 1 is immersed in an HCl solution in order to further enhance the fluoride ion adsorption ability of the carbon material 1. . However, the carbon material 1 having sufficiently high fluoride ion adsorption ability can be obtained without performing the HCl treatment. In this case, the carbon material 1 is manufactured at a low cost because the contact treatment with the HCl solution is not performed. can do.

  Next, a regeneration test performed for regenerating the carbon material 1 used for adsorption of fluoride ions with hydrochloric acid (or sulfuric acid) and examining the fluoride ion adsorption ability of the regenerated carbon material 1 will be described.

First, as the carbon material 1, 200 mg of CaCl ₂ charcoal obtained by immersing the wood chip 2 in a 10 wt% CaCl ₂ solution and heating and carbonizing at 700 ° C. for 1 hour was prepared. Then, this CaCl ₂ charcoal was put into 50 mL (standard solution) of a solution having a fluoride ion concentration of 50 mg / L (50 ppm), shaken at 200 rpm and 20 ° C. for 10 hours, and then in the standard solution. The concentration of fluoride ions was measured, and the amount of fluoride ions adsorbed by the CaCl ₂ charcoal was calculated (first time).

Subsequently, the CaCl ₂ charcoal was washed with 1 mol / L hydrochloric acid (or sulfuric acid) and further regenerated by washing with water. Thereafter, the regenerated CaCl ₂ charcoal was added to a newly prepared standard solution (that is, 50 mL of a solution having a fluoride ion concentration of 50 mg / L), shaken at 200 rpm and 20 ° C. for 10 hours, The concentration of fluoride ions in the standard solution was measured, and the adsorption amount of fluoride ions by the CaCl ₂ charcoal was calculated. Then, the processing up to the calculation of the adsorption amount of fluoride ions from the reproduction of the CaCl ₂ charcoal was carried out three times (reproducing first time - third time).

As a result of the regeneration test, that is, the adsorption amount of fluoride ions by CaCl ₂ charcoal,
First time ... 22.5mg / g
The first reproduction… 22.4mg / g
Second regeneration: 21.7 mg / g
The third regeneration ... 21.9mg / g
Met. From the above, it was confirmed that the carbon material 1 (CaCl ₂ charcoal) used for adsorption of fluoride ions was regenerated by washing with concentrated hydrochloric acid (or sulfuric acid) and further with water. This is because the CaCl ₂ charcoal on which fluoride ions are adsorbed is washed with hydrochloric acid (or sulfuric acid), and further washed with water, whereby fluoride ions are removed from the CaCl ₂ charcoal. Instead of the removed fluoride ions, Cl ^- (Or SO ₄ ^2- ) is considered to be bonded to the functional group. Further, from the result of the regeneration test, the carbon material 1 (CaCl ₂ charcoal) is used for adsorption of fluoride ions multiple times if it is regenerated by washing with hydrochloric acid (or sulfuric acid) and washing with water. It was also confirmed that it was possible.

Next, as the carbon material 1, the wood chip 2 was immersed in a 10% by weight CaCl ₂ solution, heated at 700 ° C. for 1 hour to be carbonized, and then immersed in a 5 mol / L HCl solution. using the processing CaCl ₂ charcoal, this HCl processed CaCl ₂ charcoal shows the results of similarly regeneration test as described above.

As a result of the regeneration test, that is, the adsorption amount of fluoride ions by the HCl-treated CaCl ₂ charcoal,
First time… 32.0mg / g
First reproduction: 31.5mg / g
Second regeneration: 31.4mg / g
The third regeneration ... 31.2mg / g
Met. From the above, carbon material 1 (HCl-treated CaCl ₂ charcoal) obtained by immersion treatment in HCl solution after carbonization is also used for adsorption of fluoride ions, then washed with hydrochloric acid (or sulfuric acid) solution, and further washed with water. By doing so, it was confirmed that it was reproduced. Further, the fluoride ion adsorption ability of the HCl-treated CaCl ₂ charcoal improved by the immersion treatment in the HCl solution can be obtained by repeatedly regenerating the HCl-treated CaCl ₂ charcoal by washing with hydrochloric acid (or sulfuric acid) and washing with water. It was confirmed that it persisted (it remained improved).

It is explanatory drawing which shows roughly the structure of the apparatus which manufactures the anion adsorption | suction carbon material which concerns on one embodiment of this invention. (A) is a figure which shows an example of an anion adsorption carbon material, (B) is a figure which shows the example of a process of the said anion adsorption carbon material. It is a figure which shows an example of the process of manufacturing the said carbon material using the said manufacturing apparatus. (A)-(D) are figures which show the example of application of the said carbon material. (A)-(C) is a figure which shows the detail of the process of step S2 in FIG. (A)-(C) is a figure which shows the detail of the process of step S4 in FIG. (A)-(C) is a figure which shows the detail of the process of step S5 in FIG. (A)-(D) is a figure which shows the detail of nitrate ion adsorption | suction in the said embodiment, (E) is a figure which shows the carbon material after reproduction | regeneration. It is a graph which shows the comparison result of the adsorption amount of nitrate nitrogen and nitrite nitrogen of the said carbon material and a comparison material. It is a graph showing the adsorption amount of nitrate nitrogen of the carbon material obtained by CaCl ₂ solution carbon materials and HCl treatment were prepared by varying the concentration of the step S2. It is a graph which shows the comparison result of the adsorption amount of the fluoride ion of the said carbon material and a comparison material.

Explanation of symbols

2 Raw material 3 Solution containing metal chloride

Claims (7)

A method for producing an anion-adsorbing carbon material that adsorbs anions by ion exchange of metal chlorides contained in carbides with chloride ions, wherein a solution containing metal chlorides is brought into contact with a plant material. A method for producing an anion-adsorbing carbon material comprising post-carbonizing and containing the metal chloride in the carbide. A method for producing an anion-adsorbing carbon material that adsorbs anions by ion exchange of metal chlorides contained in carbides with chloride ions , comprising a plant material in contact with a solution containing metal chlorides. A method for producing an anion-adsorbing carbon material which is carbonized and contains the metal chloride in the carbide.   The method for producing an anion-adsorbing carbon material according to claim 1 or 2, wherein a metal chloride bonded in the carbide is contained in an amount of 2% to 25% as ash.   The method for producing an anion-adsorbing carbon material according to claim 1, wherein water and / or an acid are brought into contact with the carbide.   The carbonization temperature of the said raw material is 400 to 1000 degreeC, The manufacturing method of the anion adsorption carbon material in any one of Claims 1-4. The anion adsorption carbon material manufactured by the manufacturing method of the anion adsorption carbon material in any one of Claims 1-5 . The adsorbed anion is removed from the anion adsorbing carbon material according to claim 6 adsorbing an anion, and an anion capable of ion exchange with the next anion to be adsorbed is converted into the removed anion. Anion-adsorbing carbon material that is bonded in place.

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