JP2001113272A - Method for capturing selenium or arsenic in aqueous solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently capture selenium or arsenic contained in an aqueous solution in a very small amt. by a simple method. SOLUTION: Chelate forming fibers prepared by introducing polyethyleneimine preferably having a mean mol.wt. or 300-70,000 into fiber molecules are brought into contact with a pH adjusted aqueous solution containing selenium or arsenic to capture selenium or arsenic in the aqueous solution by chelating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for trapping selenium or arsenic in an aqueous solution by using a chelating fiber in which polyethyleneimine has been introduced into fiber molecules. Selenium or arsenic present in trace amounts can be selectively captured and removed efficiently, and widely used in industrial applications such as purification of industrial water, agricultural water, wastewater, or concentration and recovery of selenium or arsenic as a valuable resource. can do

[0002]

2. Description of the Related Art Selenium and selenium compounds are widely used as industrial raw materials in various industrial fields such as coloring and decolorizing agents for glass, additives for semiconductor materials and metals, and wastewater discharged in these industrial fields. Some may contain high concentrations of selenium. Also, wastewater discharged from firepower plants contains a considerable amount of selenium, and these selenium and its compounds are generally highly toxic, and even under the Water Pollution Control Law, the selenium effluent standard is 0.1 mg. / L or less.

In order to remove selenium from wastewater, JP-A-5-78105 and JP-A-6-79286 adjust pH of wastewater and add a precipitant such as iron salt to the wastewater. A method of precipitating selenium dissolved in iron with iron hydroxide and the like. JP-A-7-2502 discloses a method of adding an iron-based metal to wastewater containing selenium to precipitate selenium on the surface of the iron-based metal. Further, a method has been proposed in which an anion exchange resin is used and adsorbed as selenic acid (hexavalent selenium) or selenous acid (tetravalent selenium).

However, of the above-mentioned conventional methods, the method of precipitating selenium with iron hydroxide or the like hardly removes hexavalent selenium ions, and the method of precipitating selenium on the surface of an iron-based metal. Therefore, it takes a long time to reduce a large amount of wastewater to a low reference concentration, and the treatment of a large amount of the generated iron-based metal is troublesome and troublesome. Since there is no selective adsorption with coexisting ions, there is a problem that the removal efficiency is extremely low in a processing solution in which various types of ions coexist.

In order to solve the problems of the conventional method, for example, JP-A-10-226832 discloses that polyethyleneimine is immobilized on a chitosan-based resin or a styrene-based resin and selectively immobilized as selenic acid or selenite. A chelating resin having the property of adsorbing is disclosed. However, these chelate resins are bead-like or granular in shape, and therefore have a small apparent surface area, and it takes a long time for the liquid to be treated to diffuse inside, so that satisfactory treatment efficiency cannot be obtained.

It has been confirmed that arsenic is contained in wastewater from the non-ferrous metal refining industry, pharmaceuticals, agricultural chemicals, pigments, petroleum plant industries, and the like, and also from thermal wastewater from geothermal power plants. Although the toxicity of arsenic, particularly trivalent arsenic, has been known for a long time, the carcinogenicity of arsenic has recently been confirmed, and its allowable amount is 0.5 pp.
m or less and 0.05 ppm or less as an environmental standard.

[0007] As a method of treating such arsenic-containing wastewater, several methods are already known. Among them, coagulation sedimentation using a metal hydroxide such as calcium, magnesium, barium, iron and aluminum is known. The method is widely used because the residual arsenic concentration can be reduced to the effluent standard by a relatively simple treatment operation. However, in this method, a large amount of chemicals must be used to treat a large amount of wastewater containing a low concentration of arsenic, such as wastewater from a geothermal power plant, and a large amount of arsenic-containing sludge generated by the treatment is required. Large load is imposed on the processing.

As the coagulation precipitation method using such a metal hydroxide, an adsorption method using activated carbon, activated alumina, silica gel or the like, a ligand ion exchange method using a cation exchange resin carrying iron or zirconium, and an anion exchange resin are used. The ion exchange method used and the like are being studied. However, the method using these adsorbents and ion exchange resins has a low adsorption capacity for arsenic, particularly harmful trivalent arsenic, has poor selective adsorption properties, and furthermore, the regeneration of adsorbents and ion exchange resins is complicated. There was a problem.

As a technique for solving these problems, Japanese Patent Application Laid-Open No. 58-64180 discloses a method for selectively adsorbing arsenic using a chelate resin in which aminopolyalcohol is immobilized on a synthetic resin. Is disclosed.
However, each of these chelate resins has a small adsorption capacity for arsenic and a bead-like or granular shape, so that the apparent surface area is small as described above, and it takes a long time for the liquid to be treated to diffuse inside. However, there is a problem that the processing efficiency is low.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to efficiently capture a small amount of selenium or arsenic in an aqueous solution by a simple method. It is to provide a method that can do it.

[0011]

The selenium or arsenic trapping method according to the present invention which can solve the above-mentioned problems includes:
After adjusting the pH of the aqueous solution containing selenium or arsenic such as the wastewater, the average molecular weight in the fiber molecule is preferably 300 to
The gist lies in that the chelating fiber having 70,000 polyethyleneimine introduced therein is brought into contact with the aqueous solution whose pH has been adjusted to capture selenium or arsenic in the aqueous solution.

The above-mentioned polyethyleneimine has a reactive functional group (hydroxyl group, amino group, imino group,
Aldehyde group, carboxyl group, thiol group, etc.), or two or more functional groups selected from an epoxy group, a reactive double bond, a halogen group, and an acid anhydride group in the molecule. It may be bonded indirectly via a cross-linking agent.

Another feature of the present invention is that the pH of the aqueous solution to be treated is adjusted in order to efficiently capture selenium or arsenic as described above. When treating the pH of the aqueous solution to 0 to 6 or treating the aqueous solution containing arsenic, a method of adjusting the pH of the aqueous solution to 2 to 8 is preferably adopted.

[0014] Further, the chelate-forming fiber having selenium or arsenic captured by the above method can be easily eluted by treating it with an alkaline aqueous solution. Not only can fibers be easily regenerated, but also selenium and arsenic can be concentrated and collected.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The method for trapping selenium or arsenic according to the present invention employs a chelating agent in which polyethyleneimine, preferably having an average molecular weight of 300 to 70,000, is introduced into fiber molecules as described above. Fibers,
It is characterized in that it is brought into contact with an aqueous solution containing selenium or arsenic whose pH has been adjusted to capture selenium or arsenic in the aqueous solution.

That is, the present invention utilizes the excellent chelating ability of polyethyleneimine with respect to selenium or arsenic, preferably having an average molecular weight of 300 to 70,000,
And by introducing the polyethyleneimine into the fiber molecule to exhibit the chelate forming ability on the surface, and further adjusting the pH of the aqueous solution containing selenium or arsenic to be treated,
Selenium or arsenic can be effectively captured.

The type of the fiber serving as the base of the chelating fiber into which polyethyleneimine has been introduced used in the present invention is not particularly limited. For example, various plant fibers such as cotton and hemp; silk and wool; Various animal fibers; various regenerated fibers such as viscose rayon; various synthetic fibers such as polyamide, acrylic and polyester can be used. These fibers can be used as needed. Although various modifications may be added, cellulosic fibers are most preferable in consideration of the ease of introduction of polyethyleneimine, wettability to the liquid to be treated, strength, stability, and the like.

There is no particular limitation on the shape of the base fiber, and long filament monofilaments, multifilaments,
It may be a spun yarn of short fibers, a fabric obtained by weaving or knitting them in a woven or knitted shape, or a nonwoven fabric. Further, it may be a fiber or a woven or knitted material obtained by compounding or blending two or more kinds of fibers.

Further, in order to increase the contact efficiency between the chelate-forming fiber and the aqueous solution to be treated, it is also effective to use the base fiber as a short fiber powder or a filter material.

The preferred shape of the short fibrous powder used here is 0.01 to 5 mm in length, preferably 0.03 to 5 mm.
3 mm and a single fiber diameter of about 1 to 50 μm, preferably 5
The aspect ratio is about 1 to 600, preferably about 1 to 100.

If such a short fiber powder material is used, it is very difficult to add the short fiber powder chelate-forming fiber to an aqueous solution containing selenium or arsenic, stir the mixture, and perform ordinary filtration. It is possible to efficiently capture and purify selenium and arsenic contained in the liquid to be treated by a simple method and in a short time. In some cases, the same trapping effect can be obtained by filling the column or the like with the chelate-forming fibers in the form of short fiber powder and passing the liquid to be treated.

The material in the form of a filter is not particularly special, and may be formed into a single-layer or multi-layer mat made of a woven, knitted or non-woven fabric having an arbitrary fiber gap according to the intended use. A structure assembled to a support, a structure in which string-like fibers are wound in multiple layers around the outer periphery of a liquid-permeable support cylinder, or a woven, knitted or nonwoven sheet made of the same fibers is folded into a pleated shape Such as a structure attached to a support member, a bag filter type in which woven / knitted fabric or nonwoven fabric made using the same fiber is formed into a bag shape, etc.
Any known form can be used.

In the present invention, the polyethyleneimine introduced into the fiber molecule is obtained by ring-opening polymerization of ethyleneimine, by polycondensation of ethylene chloride and ethylenediamine, or by heating 2-oxazolidone. Is mentioned. These raw materials of polyethyleneimine have extremely high reaction activity. In the polymerization, for example, primary, secondary and tertiary amino groups of linear structural units or branched structural units are mixed as shown in the following formula. The ratio of the structural units and the primary to tertiary amines may be any, and in the present invention, they are collectively referred to as polyethyleneimine.

[0024]

Embedded image

Among these polyethyleneimines, those exhibiting the highest chelating ability with respect to selenium and arsenic are those having an average molecular weight of 300 to 70,000, more preferably those having an average molecular weight of 600 to 10
000 polyethyleneimine.

As a method for producing the above chelate-forming fiber according to the present invention, the polyethyleneimine is added to the reactive functional group originally contained in the fiber molecule or the reactive functional group introduced by modification. React directly,
Alternatively, after reacting a compound having two or more functional groups selected from an epoxy group, a reactive double bond, a halogen group, and an acid anhydride group in the molecule as a cross-linking agent with the reactive functional group, polyethylene A method of reacting imine is employed.

The reaction when introducing polyethyleneimine into fiber molecules using these crosslinking agents is not particularly limited, but preferred methods include, for example, a method in which the base fiber and the crosslinking agent are reacted with water or N, N'-dimethylformamide or In a polar solvent such as dimethyl sulfoxide, if necessary, a reaction catalyst or an emulsifier is used in combination, and the reaction is carried out at about 60 to 100 ° C. for about 30 minutes to several tens of hours. Reacts with reactive functional groups (for example, hydroxyl groups and amino groups) to bind to the fiber,
Functional groups that readily react with polyethyleneimine can be introduced into fiber molecules. Next, the fiber into which the functional group has been introduced and polyethyleneimine are mixed with water or a polar solvent such as N, N'-dimethylformamide or dimethylsulfoxide at 60 to 100 ° C using a reaction catalyst if necessary.
When the reaction is performed for about 0 minute to several tens of hours, the amino group of the polyethyleneimine reacts with the reactive functional group (eg, an epoxy group or a halogen group) of the crosslinking agent, and the polyethyleneimine is introduced into the fiber molecule in a pendant manner. .

The amount of the polyethyleneimine introduced into the base fiber is determined in consideration of the amount of the reactive functional group in the base fiber molecule, the amount of the polyethyleneimine used for the introduction reaction, the amount of the crosslinking agent and the polyethyleneimine, and the reaction conditions. Although it can be arbitrarily adjusted by, for example, in order to impart sufficient chelate capturing ability to the fiber, the polyethyleneimine (PEI) substitution rate calculated by the following formula is about 10% by mass or more, more preferably about 20% by mass or more. It is desirable to adjust as follows. PEI substitution ratio (% by mass) = [(fiber mass after PEI introduction−fiber mass before PEI introduction) / fiber mass before PEI introduction] × 100 (where PEI represents polyethyleneimine).

In order to enhance the ability to capture selenium and arsenic, the above-mentioned PEI substitution ratio is preferably as high as possible. Therefore, the upper limit of the substitution ratio is not particularly limited. However, if the substitution ratio is too high, the crystallinity of the PEI-introduced fiber becomes high. The fibers tend to be brittle, and the pressure loss tends to increase when used as a filter medium or a filter, etc. And the PEI substitution ratio is desirably suppressed to about 130% by mass or less, and more preferably to about 100% by mass or less. However, depending on the type of the functional group or the cross-linking agent in the fiber molecule, or the application, the ability to capture selenium and arsenic can be enhanced by setting the PEI substitution rate to a high level of 150 to 200% by mass. .

The chelate-forming fiber obtained as described above can be obtained in any form such as a monofilament, a multifilament, a spun yarn, a nonwoven fabric, a fiber woven or a knitted fabric, depending on the properties of the base fiber used. However, in any case, substantially all of the polyethyleneimine introduced in a pendant form on the surface of the small-diameter fiber molecule effectively exerts the capturing performance on selenium and arsenic, and thus, for example, granular Exhibits extremely superior trapping performance as compared to trapping materials such as glass and film.

Therefore, the chelate-forming fiber is brought into contact with an aqueous solution containing selenium or arsenic, and more specifically, the fiber is laminated at an arbitrary thickness, or filled in a column and passed through the liquid to be treated. Alternatively, the fiber is added to the liquid to be treated and stirred, and a very simple method of performing a normal filtration treatment, and efficiently capturing selenium and arsenic contained in the liquid to be treated in a short time treatment. Can be cleaned.

In carrying out the method of trapping selenium or arsenic in an aqueous solution using the chelate-forming fiber, when the main focus is on trapping selenium when adjusting the pH of the aqueous solution in advance, When the pH of the aqueous solution is adjusted to the range of 0 to 6 and the main focus is on the capture of arsenic, the pH of the aqueous solution is adjusted.
By adjusting H to 2 to 8, they can be captured more efficiently. Therefore, when the treatment is performed in a region where the preferred pH region overlaps, that is, in the range of pH 2 to 6, selenium and arsenic can both be efficiently captured, and a pH region where they do not overlap with each other, for example, in the case of selenium,
By treating in the range of 0 to 2 and arsenic in the range of pH 6 to 8, selenium and arsenic can be separately captured.

Further, when the chelate-forming fiber capturing selenium or arsenic as described above is treated with an alkaline aqueous solution such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution, selenium or selenium captured by forming a chelate is obtained. Since arsenic is easily separated, the use of such characteristics not only enables the fiber to be easily regenerated, but also allows selenium and arsenic to be effectively recovered as valuable components from the eluate.

[0034]

EXAMPLES Next, examples of the present invention will be described. However, the present invention is not limited by the following examples, and the present invention should be practiced with appropriate modifications within a range that can be adapted to the gist of the preceding and the following. Of course, these are also possible, and all of them are included in the technical scope of the present invention.

(Example of synthesis of chelating fiber) Distilled water 1
In 000 ml, add ferrous ammonium sulfate hexahydrate 0.0
25 g was dissolved, and cotton yarn (4
After adding 50 g of 0/1 cotton single yarn bleached product and stirring at room temperature for 30 minutes, 50 g of glycidyl methacrylate, a nonionic surfactant (“Nonion OT-221” manufactured by NOF Corporation) 1
g, 31% H ₂ O ₂ water 0.81 g, thiourea dioxide 0.3
Add 1 g and stir at 60 ° C. for 1 hour. Next, the treated cotton yarn is washed with distilled water, drained, and then dried at 50 ° C. for 1 hour.
By drying for 5 hours, 68.5 g of a graft fiber obtained by grafting glycidyl methacrylate in a cotton yarn molecule was obtained.

Next, polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., having an average molecular weight of 60) was added to 700 g of dimethyl sulfoxide.
0) The graft fiber is immersed in a solution in which 300 g is dissolved, and heat-treated at 80 ° C. for 2 hours. Then, after sufficiently washing with water and draining, by drying at 50 ° C. for 15 hours,
90.3 g of a chelating fiber into which polyethyleneimine has been introduced (chelating fiber A) (PEI substitution ratio: 80.
6% by mass).

Example 1 (Selenium and arsenic trapping performance test in a batch system) 50 mg of the chelate fiber A obtained in the above synthesis example was treated with 10 mmol / l of selenium (IV), selenium (VI), arsenic (III) or arsenic (V). ) Is added to 25 ml of a 0.1 mol / l potassium chloride solution containing
After the mixture was stirred at 25 ° C. for 24 hours after the H adjustment, each element remaining in the solution was quantified to determine each pH.
Was confirmed. The results are as shown in FIGS. 1 and 2, and it can be seen that if this chelate fiber A is used and the treatment is performed in an appropriate pH range, selenium and arsenic of each valence can be efficiently captured (adsorbed).

Example 2 (Batch selenium capture rate test) 50 mg of the chelate fiber A obtained in the above synthesis example was treated with 10 mmol / l of selenium (V).
25 ml of 0.1 mol / l potassium chloride solution containing I)
(The pH was adjusted to 2.0 with hydrochloric acid), and the change over time in the amount of selenium (VI) adsorbed (captured) was examined. For comparison,
A similar capture (adsorption) rate test was performed using a commercially available beaded styrene-based polyamine-type anion exchange resin (trade name “Diaion WA20” manufactured by Mitsubishi Chemical Corporation) instead of chelate fiber A.

The results are as shown in FIG. 3. In the trapping method using a commercially available ion exchange resin, it takes more than 24 hours for the trapped (adsorbed) amount of selenium (VI) to be saturated.
In the removal method using the chelating fiber of the present invention into which polyethyleneimine had been introduced, it was confirmed that the trapped amount of selenium (VI) was saturated in only one hour.

Example 3 (Break-through / elution curve measurement test) 2.3 ml of the chelate fiber A obtained in the above synthesis example was filled in a glass column having an inner diameter of 5 mm, and 0.1 ml of selenium (VI) containing 1 mmol / l was added. 1 mol /
of potassium chloride solution (pH adjusted to 1.8 with hydrochloric acid) at a flow rate of SV = 75 hr- ¹ and selenium (V
I) The breakthrough curve was determined by measuring the concentration, and FIG.
Were obtained. Next, an elution curve was measured by flowing a ¹ mol / l sodium hydroxide solution at a flow rate of SV = 75 hr- ¹ , and the results shown in FIG. 5 were obtained.

For comparison, a similar test was conducted using a commercially available beaded styrene-based polyamine type anion exchange resin (trade name “Diaion WA20” manufactured by Mitsubishi Chemical Corporation) in place of chelate fiber A. However, in the case of a commercially available ion exchange resin, an acetate buffer is used in place of the potassium chloride solution, and SV = 10 hr-
^The test was performed at a flow rate of ^{1 and} the results shown in FIGS.

As is clear from comparison of FIGS. 4 and 6 showing breakthrough curves, in the column-type removal method using a commercially available ion exchange resin, selenium (VI) flows out before it is sufficiently adsorbed. On the other hand, in the column-type removal method using the chelating fiber of the present invention into which polyethyleneimine has been introduced (FIG. 6), complete adsorption capacity is exhibited until the adsorption of selenium (VI) reaches saturation. (FIG. 4).

In the elution curve, when a commercially available ion exchange resin was used (FIG. 7), the curve was broad and the elution time was long, whereas the chelating fiber of the present invention into which polyethyleneimine was introduced was used. In the case (FIG. 5), the curve is very sharp and the elution time is short.

[0044]

The present invention is configured as described above. If the capturing method of the present invention is adopted, not only a high capturing / removing effect on selenium or arsenic can be obtained, but also the capturing speed is remarkably increased. It is excellent and can capture and remove selenium and arsenic in wastewater extremely efficiently as compared with conventional ion exchange resins and chelate resins, and can purify them very effectively. Moreover, the chelate-forming fibers capturing selenium or arsenic can be easily separated from the selenium or arsenic by treating with an aqueous alkali solution, so that the selenium or arsenic can be easily regenerated and reused. It can also be used for concentrated sampling. In addition, if chelate-forming fibers such as a nonwoven fabric or a fabric are used, it is easy to use them as a cartridge system to enhance exchangeability and other workability. It can be easily incinerated by an incinerator.

[Brief description of the drawings]

FIG. 1 shows the results when the chelate fiber A obtained in Example was used.
4 is a graph showing the pH dependence of the amount of selenium (VI) and selenium (IV) captured.

FIG. 2 shows the results when the chelate fiber A obtained in the example was used.
4 is a graph showing the pH dependence of the amount of arsenic (V) and arsenic (III) captured.

FIG. 3 is a graph showing a change over time in the amount of selenium (VI) captured (adsorbed) when the chelate fiber A obtained in the example or a commercially available beaded styrene-based polyamine type anion exchange resin is used. is there.

FIG. 4 shows the use of chelate fiber A obtained in the example,
6 is a graph showing a breakthrough curve when (VI) is captured (adsorbed).

FIG. 5: Chelate fiber A that has broken through by capturing selenium (VI)
6 is a graph showing an elution curve when selenium (VI) was eluted by treating selenium (VI) with an alkaline solution.

FIG. 6 is a graph showing a breakthrough curve when selenium (VI) is captured (adsorbed) using a commercially available beaded styrene-based polyamine type anion exchange resin.

FIG. 7 is a graph showing an elution curve when selenium (VI) is eluted by treating a commercially available beaded styrene-based polyamine type anion exchange resin that has captured and passed selenium (VI) with an alkaline solution. It is.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshinari Inuyo 807-1, Nonoshita, Sukumachi, Tosu-shi, Saga Prefecture Inside the Kyushu Institute of Technology (72) Inventor Yasuhiko Kaida 807, Nonoshita, Sukumachi, Tosu-shi, Saga No. 1 Institute of Industrial Technology Kyushu Institute of Industrial Technology (72) Inventor Seiji Yasuda 807 Nonoshita, Sukumachi, Tosu City, Saga Prefecture Inside Institute of Industrial Technology Kyushu Institute of Industrial Technology (72) Inventor Yoshitake Mihara Chiba City, Chiba Prefecture 1682-551, Nagasaku-cho, Hanamigawa-ku (72) Inventor Nobuyoshi Nambu 3-3-3, Hinagahigashi, Yokkaichi-shi, Mie Chubu Kirest Co., Ltd. Yokkaichi Plant -3 Chubu Killest Co., Ltd. Yokkaichi Plant (72) Inventor Takao Doi 3- 3-3 Hinagahigashi, Yokkaichi City, Mie Prefecture Chubu Killest Co., Ltd. Company Yokkaichi plant in the F-term (reference) 4D025 AA09 AB24 BA17 BA25 CA03 4F073 AA11 BA02 BA03 BA18 BA23 BA29 BB01 EA01 EA11 EA13 EA25 EA65 EA76 HA04 4J031 AA01 AA03 AA20 AA35 AA36 AA37 AA49 AA55 AA57 AB06 AC07 AC09 AE11 AF07

Claims (12)

[Claims] 1. The method according to claim 1, wherein the chelating fiber having polyethyleneimine introduced into the fiber molecule is brought into contact with an aqueous solution containing selenium or arsenic whose pH has been adjusted, and selenium or arsenic in the aqueous solution is captured. A method for capturing selenium or arsenic in an aqueous solution. 2. The method according to claim 1, wherein the polyethyleneimine has an average molecular weight of 300 to 70,000. 3. The capturing method according to claim 1, wherein the polyethyleneimine is directly bonded to a reactive functional group in a fiber molecule. 4. The capturing method according to claim 1, wherein said polyethyleneimine is introduced into a reactive functional group in a fiber molecule via a crosslinking agent. 5. The capturing method according to claim 4, wherein the crosslinking agent is a compound having two or more functional groups selected from an epoxy group, a reactive double bond, a halogen group, and an acid anhydride in a molecule. . 6. The cross-linking agent is at least one selected from the group consisting of glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether, epichlorohydrin, ethylene glycol diglycidyl ether, maleic anhydride, and itaconic anhydride. Item 6. The capturing method according to Item 5. 7. The capturing method according to claim 1, wherein the fiber is a natural fiber or a regenerated fiber. 8. The method according to claim 7, wherein the natural fiber or the regenerated fiber is a cellulosic fiber. 9. The capturing method according to claim 1, wherein the fiber is a synthetic fiber. 10. The method according to claim 1, wherein the pH of the aqueous solution containing selenium is adjusted to 0 to 6 to bring the aqueous solution into contact with the chelating fiber.
10. The capturing method according to any one of claims 9 to 9. 11. The arsenic-containing aqueous solution is adjusted to a pH of 2 to 8 and brought into contact with the chelating fiber.
10. The capturing method according to any one of 9. 12. A method for regenerating chelate-forming fibers, wherein the selenium or arsenic is eluted from the chelate-forming fibers using an alkaline aqueous solution after performing the capturing method according to claim 1.