JP5889554B2 - ORGANIC COMPOUND ADSORBENT HAVING HAZARDOUS METAL OR π BOND, ITS MANUFACTURING METHOD, AND ORGANIC COMPOUND ADSORBING METHOD HAVING HAZARDOUS METAL OR π BOND - Google Patents

Description

  The present invention relates to a hazardous substance treating agent containing white clay substituted with a metal cation, a method for producing the treating agent, and a harmful substance treating method using the treating agent.

The majority of household waste is disposed of at public incineration plants, but in the case of incineration, in addition to fine fly ash and incinerator ash that accumulates on the bottom of the furnace, various harmful substances {hydrogen chloride, dioxins, sulfur Oxides (SOx), heavy metal fine particles, etc.} are generated.
In order to suppress the release of harmful substances into the atmosphere, in ordinary incinerators, slaked lime powder is used to fix hydrogen chloride and SOx, and activated carbon powder is blown into the flue to fix dioxins. And powders (hereinafter referred to as fly ash) in which harmful substances are immobilized are collected with a bag filter. Since the recovered fly ash contains heavy metals such as lead with a low melting point, water is added to prevent the fly ash from scattering into the air, and a chelating agent is added to suppress the elution of heavy metals. Has been.
In addition, it has been frequently reported that the soil of the site of the chemical product factory contains heavy metals, hydrogen chloride, dioxins and sulfur oxides (SOx) that exceed legal standards. Furthermore, there is a problem that the aqueous solution eluted from the soil flows into the river.

The following has been reported on materials for removing heavy metals.
Patent Document 1 discloses that acidic clay, which is a montmorillonite clay, can remove dioxins, hydrocarbons, and lead.
However, this document does not disclose or suggest "white clay substituted with alkali metal".

Patent Document 2 states that “the swellable inorganic layered compound is not limited to a specific compound. For example, Na-montmorillonite, Ca-montmorillonite, acid clay, synthetic smectite, Na-hectorite, Li-hectorite, Na— At least one member of the group consisting of teniolite, Li-teniolite and synthetic mica is disclosed. "
However, this document does not disclose or suggest "white clay substituted with alkali metal".

Patent Document 3 states that “there are various solid acids, but first, natural clay minerals such as acid clay, fuller's earth, montmorillonite, bentonite, kaolin, clarit, phlorizin, etc., having a specific surface area of 150 m ² / g or more, 500 m ² / and those processed so as to be less than or equal to g ”.
However, this document does not disclose or suggest "white clay substituted with alkali metal".

Currently, slaked lime (for removing hydrogen chloride), activated carbon (for removing dioxins), and chelating agents (for fixing heavy metals) are used as materials for removing harmful substances generated during waste incineration. However, since activated carbon and a chelating agent are expensive, an inexpensive alternative is desired.
In addition, montmorillonite, which has been conventionally known as a cation exchanger, is expensive, and even if heavy metals can be removed, dioxins cannot be removed from the structure of montmorillonite. There were drawbacks.

JP2006-263587 JP 06-277451 A JP 08-010739

  An object of the present invention is to provide a material that has an ability to remove harmful substances, particularly heavy metals and aromatic compounds, which is easy to manufacture and low in cost, in order to solve the above-described problems of the prior art.

  As a result of intensive research in order to solve the above-mentioned problems, the present inventors have found that white clay substituted with a metal cation (sometimes referred to as “metal cation-substituted white clay”), in particular, white clay substituted with sodium ions (“sodium” Sometimes referred to as “ion-substituted clay”, clay-substituted clay (sometimes referred to as “lithium-ion-substituted clay”), and potassium-substituted clay (sometimes referred to as “potassium-ion-substituted clay”). Was found to have an excellent ability to adsorb metals and aromatic compounds, and the present invention was completed.

That is, the present invention is as follows.
1. Hazardous substance treatment agent containing white clay substituted with metal cations.
2. 2. The hazardous substance treating agent according to 1 above, wherein the metal cation is an alkali metal or an alkaline earth metal.
3. 3. The hazardous substance treating agent according to 2 above, wherein the alkali metal is sodium.
4). 3. The hazardous substance treating agent according to 2 above, wherein the alkali metal is lithium.
5. 3. The hazardous substance treating agent according to 2 above, wherein the alkali metal is potassium.
6). 6. The hazardous substance treating agent according to any one of 1 to 5 above, wherein the white clay is an acidic white clay or an activated white clay.
7). 7. The hazardous substance treating agent according to any one of 1 to 6 above, wherein the content of the metal cation is 0.5 to 6.0% by weight.
8). A method for producing a hazardous substance treating agent comprising a white clay obtained by ion-exchanging white clay with an alkali metal salt and / or an aqueous solution containing an alkaline earth metal salt and substituted with an alkali metal and / or an alkaline earth metal.
9. 9. The method for producing a treating agent according to 8 above, wherein the clay is acidic clay or activated clay.
10. 10. The method for producing a treating agent according to 8 or 9 above, wherein the alkali metal salt is sodium chloride.
11. 10. The method for producing a treating agent according to 8 or 9 above, wherein the alkali metal salt is lithium chloride.
12 10. The method for producing a treating agent according to 8 or 9 above, wherein the alkali metal salt is potassium chloride.
13. 8. A method for treating a hazardous substance, comprising removing the metal in the solution by bringing the agent for treating a hazardous substance according to any one of items 1 to 7 into contact with a solution containing the metal.

The heavy metal removal ability of the hazardous substance treating agent containing sodium ion-substituted clay, lithium ion-substituted clay, or potassium ion-substituted clay, which is a part of the present invention, was superior to that of acid clay.
Furthermore, the aromatic compound removing ability of the treating agent was superior to the aromatic compound removing ability of the acid clay.
If the hazardous material treatment agent containing the metal cation-substituted clay of the present invention is used as a purification material for waste treatment instead of acid clay, the removal rate of heavy metals and aromatic compounds can be improved, and the cost of waste treatment can be reduced. Can be reduced.

Acid clay {AC: (a)}, lithium ion-substituted clay {Li-AC (b)}, sodium ion-substituted clay {Na-AC (c)}, potassium ion-substituted clay {K-AC (d)} and sodium XRD pattern of type montmorillonite {Na-MMT: (e)}. ●: Montmorillonite, △: α-quartz, ▲: α cristobalite (Example 1) Example 2 (A) Cadmium ion (Cd ²⁺ ) and (b) Lead ion (Pb ²⁺ ) removal behavior over time of acid clay (AC; ●) and sodium ion-substituted clay (Na-AC; ■) ). Acid clay (AC; ●) and sodium ion substitution clay (Na-AC; ■) of ^{(a) Ni 2+, (b} ) Zn 2+, adsorption isotherm for (c) Cd ² + and (d) Pb ²⁺ Line (Example 2). Low concentrations of acid clay (AC; ●) and sodium ion-substituted clay (Na-AC; ■) for (a) Ni ²⁺ , (b) Zn ²⁺ , (c) Cd ²⁺ and (d) Pb ²⁺ Zone adsorption isotherm (Example 2). Pb ²⁺ of acidic clay (AC; ●), lithium ion-substituted clay (Li-AC; ▼), sodium ion-substituted clay (Na-AC; ■) and potassium ion-substituted clay (K-AC; ▲) against Pb ²⁺ (B) Adsorption isotherm in the low concentration range (Example 3). Adsorption isotherms of acid clay (AC), lithium ion-substituted clay (Li-AC), sodium ion-substituted clay (Na-AC), potassium ion-substituted clay (K-AC), and sodium-type montmorillonite (Na-MMT) on benzene (Example 4).

(Toxic substance treating agent containing white clay substituted with metal cation of the present invention)
The hazardous substance treating agent containing white clay substituted with the metal cation of the present invention (hereinafter sometimes referred to as “the hazardous substance treating agent of the present invention”) selectively adsorbs metals (particularly heavy metals) and aromatic compounds. It has the property to do.
The harmful substance of the present invention means a substance that adversely affects the environment and / or living body, such as a metal (particularly heavy metal), an organic compound having a π bond {particularly an aromatic compound (more specifically, dioxins)}. To do.

(White clay used in the present invention)
The clay used in the present invention may be either acid clay or activated clay.
The composition of the acid clay used in the present invention is different from the composition of ordinary montmorillonite group clay minerals and has a relatively high SiO ₂ content and a relatively low Al ₂ O ₃ content. For example, the acid clay used in the present invention is preferably an acid clay produced in Yamagata Prefecture.
Activated clay is obtained by treating acid clay with sulfuric acid or the like, and is widely used industrially as an oil refining (decoloring) agent.

(Metal cation)
As the metal cation of the present invention, any ion belonging to an alkali metal cation and an alkaline earth metal cation containing magnesium can be used. Preferred metal cations are as follows. Particularly preferred metal cations are sodium ion, lithium ion and potassium ion.
(1) potassium ion, (2) rubidium ion, (3) calcium ion, (4) magnesium ion, (5) sodium ion, (6) lithium ion.
In addition, the above metal cations can be mixed and used.
That is, the hazardous substance treating agent containing white clay substituted with the metal cation of the present invention is preferably substituted with the above-described ions or a mixture thereof.

(Method for producing white clay substituted with metal cation)
Acid clay is a three-layer structure consisting of SiO ₄ tetrahedral layers -AlO ₆ octahedral layer -SiO ₄ tetrahedral layers as a basic structure, in such a three-layer assembly of structures several sheets laminated fine monocrystal is there. In addition, cations such as Ca, K, and Na and water molecules coordinated therewith exist between the laminated layers having such a three-layer structure.
The method for producing the metal cation-substituted clay according to the present invention is not particularly limited as long as the cation in the pores of the clay can be substituted with the target metal cation, alkali metal cation and / or alkaline earth metal cation.
For example, powdered clay is put into an aqueous solution containing a metal cation, an alkali metal cation and / or an alkaline earth metal cation, and preferably stirred to mix the ions in the pores with the metal cation in the aqueous solution. A metal cation-substituted clay can be produced by promoting ion exchange, and then washing and drying the clay.

(Method for producing sodium ion-substituted white clay)
Although the following method is mentioned as the manufacturing method of the sodium ion substituted clay of this invention, for example, It does not specifically limit.
1.0 g of acid clay is stirred for 8 hours in 100 cm ³ of 0.5 M (mol · dm ⁻³ ) aqueous sodium chloride solution, and after solid-liquid separation, it is obtained by washing and drying.

(Composition of sodium ion-substituted clay)
The content (% by weight) of the metal cation in the sodium ion-substituted clay of the present invention is 0.5 to 6.0, preferably 1.0 to 5.5, more preferably 2.0 to 5.0.
The composition of the sodium ion-substituted clay according to the present invention is clearly different from the composition of Na-type montmorillonite. For example, the CaO concentration (% by weight) in the composition of the sodium ion-substituted clay is 0.05 to 0.50, preferably 0.10 to 0.40, and more preferably 0.15 to 0.30. On the other hand, the CaO concentration (% by weight) in the composition of Na-type montmorillonite is generally 0.51 or more.
Further, SiO ₂ concentration in the composition of the sodium ion substitution clay of the present invention (wt%), 60.0 to 90.0, preferably 63.0 to 80.0, more preferably 65.0 to 75.0. On the other hand, the SiO ₂ concentration (wt%) in the composition of Na-type montmorillonite is generally 59.0 or less.
In addition, the specific surface area of the sodium ion-substituted clay of the present invention is clearly different from the specific surface area of Na-type montmorillonite. The specific surface area (m ² · g ⁻¹ ) of the sodium ion-substituted clay is 50.0 to 120.0, preferably 60.0 to 110.0, and more preferably 70.0 to 100.0. On the other hand, the specific surface area (m ² · g ⁻¹ ) of Na-type montmorillonite is 10.0 to 30.0.

(Media to be processed in the present invention)
The medium to be treated using the hazardous substance treating agent of the present invention varies depending on the harmful substance to be treated.
When processing heavy metals, the medium is preferably a liquid. For example, water-soluble effluents, particularly water-soluble effluents derived from general or industrial waste, are targeted, but not particularly limited.
More specifically, it is formed with aqueous solutions from washing fly ash resulting from incineration of waste, especially household dust, industrial waste or hospital waste, aqueous solution effluent from soil, or aqueous solution from soil washing. Water-soluble effluent is the medium. In addition, since an appropriate amount of water is added to the fly ash in order to suppress scattering of the waste incineration fly ash into the air, the heavy metal eluted from the fly ash can be made into a water-soluble discharge.
When treating aromatic compounds, the medium is preferably a gas. For example, a gas discharged from garbage containing an organic substance is targeted, but not particularly limited.
More specifically, the medium is gas generated from incineration of waste, especially household dust, industrial waste or hospital waste.

(Ammonia and metals contained in the processing medium)
One or more metals from cadmium, chromium, cobalt, copper, tin, manganese, mercury, nickel, lead, thallium, silver, zinc, iron, cesium as ammonia and metals, especially heavy metals, contained in the processing medium What is selected can be exemplified.
Particularly, heavy metals to be treated with the treating agent of the present invention are nickel, zinc, cadmium and lead.
Note that heavy metal to be removed, usually in the form of ions, especially in the form of their respective cations ^{(e.g., Cr 3+, Cu 2 +,} Ni 2+, Fe 2+, Fe 3+, Cd 2+, Hg ²⁺ , Pb ²⁺ , Zn ²⁺ or Cs ⁺ ).

(Organic compound having π bond contained in the medium to be treated)
Examples of the organic compound having a π bond, particularly an aromatic compound, contained in the medium to be treated, particularly a gaseous medium, include toluene, triphenylmethane, benzene, phenol, naphthalene and the like. In addition, so-called dioxins such as polychlorinated dibenzoparadoxine (PCDD), especially 2,3,7,8-tetrachlorodibenzo-1,4-dioxin (TCDD), polychlorinated dibenzofuran (PCDF), especially 2,3,7, Examples also include 8-tetrachlorodibenzofuran (TCDF) and polychlorinated biphenyl.
As is clear from Example 4 below, the harmful substance treating agent of the present invention was able to adsorb and remove benzene, which Na-MMT was able to adsorb very little. Furthermore, the adsorption removal capability of the treatment agent is higher than that of acid clay (AC).

(Method of using the hazardous substance treating agent of the present invention)
The method for using the hazardous substance treating agent of the present invention can be exemplified as follows, but is not particularly limited.
When removing heavy metals (1) The clay powder substituted with metal cations is added to a solution containing the metal to be removed and stirred to adsorb the metals. Further, the metal is removed from the solution by solid-liquid separation of the used powder from the solution.
(2) The column is filled with white clay powder substituted with metal cations. Further, the solution containing the metal to be removed is passed through the column to separate the metal from the solution.
(3) The white clay powder substituted with the metal cation and the solid containing the metal to be removed are mixed in water, and the metal eluted from the solid is adsorbed and removed with the white clay.

When removing an aromatic compound (1) The white clay powder substituted with a metal cation is brought into contact with a gas containing the aromatic compound to be removed, thereby adsorbing the aromatic compound. Further, the aromatic compound is removed from the gas by separating spent powder from the gas.
(2) The column is filled with white clay powder substituted with metal cations. Further, a gas containing the aromatic compound to be removed is passed through the column to separate the aromatic compound from the gas.

In addition, by washing the used hazardous substance treating agent with high-concentration NaCl, it can be regenerated into a sodium ion-substituted white clay and reused.
Moreover, it can carry out on normal temperature or normal pressure conditions as conditions at the time of use of the hazardous | toxic substance processing agent of this invention. Furthermore, since the hazardous substance treating agent of the present invention does not contain harmful substances, it does not need to be used in a special facility.

  Hereinafter, the present invention will be described specifically by way of examples. These examples are for explaining the present invention, and do not limit the scope of the present invention.

(Characteristic evaluation of alkali metal ion-substituted clay)
The structure and composition of lithium ion-substituted clay, sodium ion-substituted clay, and potassium ion-substituted clay were evaluated in comparison with acidic clay and Na-type montmorillonite. Details are shown below.

(Used acid clay)
The acid clay (AC) used was a product from Mizusawa Chemical Industry Co., Ltd. from Tsuruoka City, Yamagata Prefecture. More specifically, AC was prepared by crushing and drying at 110 ° C.

(Na-type montmorillonite used)
The Na-type montmorillonite (Na-MMT) used was a product of Klimine Industry Co., Ltd. More specifically, Na-MMT was prepared by drying at 110 ° C. after crushing.

(Manufacture of used alkali metal ion-substituted clay)
The lithium ion-substituted clay (Li-AC) used was obtained by stirring 1.0 g of AC in paragraph “0027” in 100 cm ³ of 0.5 M (mol · dm ⁻³ ) LiCl aqueous solution for 8 hours, solid-liquid separation, deionization It was prepared by washing at 110 ° C after washing with water.
The used sodium ion-substituted clay (Na-AC) was prepared by stirring 1.0 g of AC of paragraph “0027” in 100 cm ³ of 0.5 M NaCl aqueous solution for 8 hours, solid-liquid separation, washing with deionized water, 110 ° C. It was prepared by drying with.
The potassium ion-substituted clay (K-AC) used was 110 ° C after stirring 1.0 g AC of paragraph “0027” in 100 cm ³ of 0.5 M KCl aqueous solution for 8 hours, solid-liquid separation and washing with deionized water. It was prepared by drying with.

(Evaluation of structure and composition)
Regarding AC, Li-AC, Na-AC, K-AC and Na-MMT, chemical composition is determined by X-ray fluorescence (XRF) and thermal analysis (TG), specific surface area is determined by BET method, crystal phase is powder Evaluation was made by X-ray diffraction (XRD; using CuKα rays).
The conditions of XRF and TG used in the measurement of the chemical composition and the conditions of the BET method used in the measurement of the specific surface area are as follows.
1. XRF ZSX Primus (Rigaku), radiation source: RhKα, voltage: 50 kV, current: 30 mA
2. TG Thermo Plus (Rigaku), measuring temperature range: room temperature to 1000 ° C, heating rate: 1 ° C / min, standard sample: α-Al ₂ O ₃
3. BET method BELSORP 18SP (Nippon Bell), pretreatment: 200 ° C 12 h, measurement temperature: 77 K, adsorption species: nitrogen, calculated from nitrogen adsorption isotherm

The XRD patterns of AC (a), Li-AC (b), Na-AC (c), K-AC (d) and Na-MMT (e) are shown in FIG. AC was identified as a mixture of α-cristobalite and α-quartz, mainly composed of montmorillonite compounds responsible for decolorization performance.
Regarding AC, the 001 peak is weaker and broader than the 001 peak of Na-MMT, and is slightly shifted to the lower angle side. Therefore, the distance between the bottom surfaces of AC was calculated to be about d = 1.53 nm.
Regarding Li-AC, the 001 peak is much weaker and broader than the 001 peak of Na-MMT, and is shifted to the high angle side. Therefore, the distance between the bottom surfaces of Li-AC was calculated to be about d = 1.07 nm. There was no change compared to AC except for the bottom peak of Li-AC.
Regarding Na-AC, the 001 peak is much weaker and broader than the 001 peak of Na-MMT, and is shifted to the high angle side. Therefore, the distance between the bottom surfaces of Na-AC was calculated to be about d = 1.01 nm. There was no change compared with AC except for the bottom peak of Na-AC. In addition, Na-AC in water showed swelling properties. The expression of this swelling suggests that Na ⁺ was inserted between the layers of the montmorillonite phase by NaCl treatment.
Regarding K-AC, the 001 peak is much weaker and broader than the 001 peak of Na-MMT, and is shifted to the high angle side. Therefore, the bottom spacing of K-AC was calculated to be about d = 1.07 nm. There was no change compared to AC except for the bottom peak of K-AC.

Table 1 shows the composition analysis results of AC, Na-AC, K-AC and Na-MMT by XRF method and TG method.
When the composition of Na-AC is compared with that of AC, the amount of Na ₂ O is remarkably increased, the amount of CaO is remarkably decreased, and MgO is slightly decreased for the other components, with almost no decrease in weight. It was. This result indicates that, due to NaCl treatment, Ca ²⁺ between layers is mainly ion-exchanged to Na ⁺ , and the interlayer ionic species becomes Na ⁺ like Na-MMT. The reason why Cl is detected in the Na-AC composition is considered to be due to NaCl treatment.
Comparing the composition of K-AC with AC, the amount of K ₂ O is significantly increased, the amount of CaO is remarkably decreased, and MgO is slightly decreased for the other components, with almost no decrease in weight. It was. This result indicates that, due to the KCl treatment, mainly Ca ²⁺ between layers was ion-exchanged to K ⁺ and the interlayer ionic species became K ⁺ .
The order of weight loss up to 1000 ° C was AC>Na-MMT> Na-AC ≒ K-AC, which was consistent with the order of the interlaminar water volume predicted from the bottom surface spacing.

The specific surface areas of AC, Li-AC, Na-AC, K-AC and Na-MMT calculated by the BET method were 80, 91, 84, 97 and 15 m ² · g ⁻¹ , respectively.

(Evaluation of metal removal characteristics of sodium ion-substituted clay)
The metal removal rate and metal removal ability of Na-AC produced in paragraph “0029” were evaluated. The heavy metals to be removed were Ni, Zn, Cd and Pb with reference to the composition analysis result of the waste incineration fly ash. The measurement conditions were room temperature and a batch method.

(Measurement of metal removal rate)
Add 0.5 g of sample (AC and Na-AC) to 100 cm ³ of about 10 to 100 ppm chloride aqueous solution (MCl ₂ : M = Cd, Ni, Pb, Zn), and shake for a predetermined time (5 minutes to 24 hours). Stir in a vessel.
After stirring, solid-liquid separation is performed using a centrifuge, and heavy metal ions and ions desorbed from Na-AC in the filtrate are analyzed by atomic absorption spectrometry (AA). Qe (adsorption amount: mmol · g ⁻¹ ) was calculated.
Incidentally, C _i and C _e of formula 1, respectively, refers to the initial concentration (mmol · dm ^-3) and the equilibrium concentration (mmol · dm ^-3). V represents the volume (dm ³ ) of the MCl ₂ aqueous solution, and W represents the mass (g) of the sample.

(Measurement of metal removal)
0.5 g of a sample was added to 100 cm ³ of an aqueous chloride solution (MCl ₂ : M = Cd, Ni, Pb, Zn) of about 10 to 1500 ppm, and the mixture was stirred with a shaker for 1 hour.
After stirring, solid-liquid separation is performed using a centrifuge, and heavy metal ions and ions desorbed from Na-AC in the filtrate are analyzed by atomic absorption spectrometry (AA), and Q _e (adsorption) is performed as in paragraph “0036”. Amount; mmol · g ⁻¹ ) was calculated.

(Measurement result of metal removal rate)
Time course of AC and Na-AC metal ion removal behavior (ion adsorption amount of each sample) for 11 ppm (about 0.1 mmol · dm ^-3 ) CdCl ₂ aqueous solution and 54 ppm (0.26 mmol · dm ^-3 ) PbCl ₂ aqueous solution The change is shown in FIG. All samples took Cd ²⁺ and Pb ²⁺ in a short time and reached steady state.
The reaction proceeded to Ni ²⁺ and Zn ^{2+ in} a short time and reached a steady state (not shown).
As described above, the contact time between the sample and the solution for measuring the adsorption isotherm was determined to be 1 hour. Thereby, the contact time between the sample and the solution in the measurement of the metal removal amount was set to 1 hour.

(Measurement result of metal removal amount)
FIG. 3 shows the adsorption isotherms of AC and Na-AC for Ni ²⁺ , Zn ²⁺ , Cd ²⁺ and Pb ²⁺ . They were selectively incorporated into any metal ion. Na-AC showed stronger selectivity than AC for any high concentration of metal ions.
FIG. 4 shows adsorption isotherms at low concentrations of AC and Na-AC for Ni ²⁺ , Zn ²⁺ , Cd ²⁺ and Pb ²⁺ . Na-AC was selectively incorporated for any low concentration of metal ions.
As described above, Na-AC can selectively adsorb and remove metals, particularly heavy metals, from a low concentration range to a high concentration range.

(Evaluation of metal removal characteristics of lithium ion-substituted clay and potassium-substituted clay)
The metal removal ability of Li-AC and K-AC produced in paragraph “0029” was evaluated. The heavy metal to be removed was the most important Pb. The measurement conditions were room temperature and a batch method.

(Measurement of metal removal)
A sample of 0.5 g was added to 100 cm ³ of a PbCl ₂ aqueous solution of about 10 to 1500 ppm, and the mixture was stirred with a shaker for 1 hour. After stirring, solid-liquid separation is performed using a centrifuge, and lead ions in the filtrate and ions desorbed from Li-AC and K-AC are analyzed by atomic absorption spectrometry (AA). As in paragraph “0036” Qe (adsorption amount: mmol · g ⁻¹ ) was calculated.

(Measurement result of metal removal amount)
The adsorption isotherms of AC, Li-AC, Na-AC, and K-AC with respect to Pb ²⁺ are shown in FIG. 5 {(a); entire measured concentration range, (b); low concentration range}. Both metal ion-substituted clays selectively incorporated Pb2 ⁺ . Since clay is a natural resource, there is some variation, but the order of selectivity is basically Na-AC>K-AC> Li-AC ≒ AC, and Na-AC is from a low concentration range. While the strongest selectivity for Pb ^{2+ was observed} over a high concentration range, the selectivity of Li-AC was similar to that of AC.
As described above, Na-AC can most selectively adsorb and remove Pb ²⁺ .

(Evaluation of aromatic compound removal characteristics of metal ion-substituted clay)
The aromatic compound removing ability of Li-AC, Na-AC and K-AC produced in the paragraph “0029” was compared and evaluated with the aromatic compound removing ability of AC and Na-MMT. In addition, benzene of an aromatic compound which is a compound having a π bond was targeted for removal.

(Measurement of aromatic compound removal)
The amount of benzene adsorbed on each sample was measured using a gas adsorption meter under the following conditions.
<Measurement conditions>
Gas adsorption measuring instrument: Bell Soap 18 (Nippon Bell)
Sample amount (AC, Li-AC, Na-AC, K-AC, Na-MMT): 0.1 g
Pretreatment temperature: 200 ° C (under vacuum)
Pretreatment time: 12h or more Adsorption gas: High-purity benzene Adsorption temperature: 25 ℃
Air bath temperature: 30 ℃
Adsorption range: 0.3-0.9 relative pressure

(Measurement result of aromatic compound removal amount)
Fig. 6 shows adsorption isotherms for benzene of AC, Li-AC, Na-AC, and K-AC. All samples showed benzene adsorption, but Na-MMT showed very little benzene adsorption. Among them, K-AC adsorbed the most benzene, and its adsorption amount was about 40 mL (STP) / g, which was about 4 times the adsorption amount of AC. In particular, by replacing with K ⁺ and Na ⁺ , the adsorption performance in the low pressure range (low concentration range) was improved. The order of benzene adsorption performance of these samples was K-AC>Na-AC> Li-AC ≧ AC.
As described above, the hazardous substance treating agent of the present invention has an excellent aromatic compound removing ability as compared with AC.

(General)
According to Examples 2 to 4, when AC is converted to an alkali metal type, particularly Na type or K type, the amount of incorporation into heavy metals increases, and the amount of adsorption to aromatic compounds that are compounds having π bonds also increases.

  If the hazardous substance treating agent containing sodium ion-substituted clay or potassium ion-substituted clay according to the present invention is used, the removal rate of heavy metals and aromatic compounds is improved, so that the cost for waste treatment can be reduced.

Claims (13)

An organic compound adsorbent having a toxic bond or a toxic bond containing white clay substituted with sodium chloride or white clay substituted with potassium chloride.
The organic compound adsorbent having harmful metal or π bond according to claim 1, comprising white clay substituted with sodium chloride.
The organic compound adsorbent having harmful metal or π bond according to claim 2, comprising white clay substituted with potassium chloride.
The organic compound adsorbent according to any one of claims 1 to 3, wherein the harmful substance is an organic compound having a π bond .
The organic compound adsorbent according to claim 4, wherein the organic compound having a π bond is an aromatic compound.
The organic compound adsorbent according to any one of claims 1 to 5, wherein the clay is acidic clay or activated clay.
The organic compound adsorbent according to any one of claims 1 to 6, wherein the sodium or potassium content is 0.5 to 6.0 wt%.
A method for producing an organic compound adsorbent having a harmful metal or π bond containing white clay substituted with sodium chloride and / or potassium chloride obtained by ion exchange of white clay with an aqueous solution containing sodium chloride and / or potassium chloride.
The method for producing an organic compound adsorbent having a harmful metal or π bond according to claim 8, wherein the clay is acidic clay or activated clay.
The method for producing an organic compound adsorbent having harmful metals or π bonds according to claim 8 or 9, wherein the aqueous solution containing sodium chloride and / or potassium chloride is an aqueous solution containing sodium chloride.
The method for producing an organic compound adsorbent having harmful metals or π bonds according to claim 8 or 9, wherein the aqueous solution containing sodium chloride and / or potassium chloride is an aqueous solution containing potassium chloride.
The method for producing an organic compound adsorbent according to any one of claims 8 to 11, wherein the harmful substance is an organic compound having a π bond .
The harmful compound in any one of claims 1 to 7 is brought into contact with a solution containing a harmful metal and / or an organic compound having a π bond by contacting the organic compound adsorbent having the harmful metal or the π bond. An organic compound adsorption method having a harmful metal or π bond, wherein the organic compound having a metal and / or π bond is removed.

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