JP2009137801A - New material, purification method, method for producing layered double hydroxide, composite material and method for producing the same, adsorbent, purification facility, and method for purifying contaminated water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a high-level purification by exhibiting a high-level adsorption ability to heavy metals contained in a contaminant or contaminated water without performing treatment such as a pretreatment for removing CO<SB>3</SB><SP>2-</SP>between the layers of a layered double hydroxide. <P>SOLUTION: A new material produces soluble divalent and trivalent cations when it is brought into contact with a component in water and spontaneously produces a layered double hydroxide [M<SP>2+</SP><SB>(1-x)</SB>M<SP>3+</SP><SB>x</SB>(OH)<SB>2</SB>]<SP>x+</SP>[A<SP>n-</SP><SB>x/n</SB>-yH<SB>2</SB>O]<SP>x-</SP>(M: cation, A: anion) in a pH range of 6-12.5. The divalent cation is preferably magnesium, manganese, calcium, nickel, cobalt, copper, zinc, or iron, or a combination thereof. The trivalent cation is preferably aluminum, manganese, iron, or cobalt, or a combination thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a kind of mineral, a novel material relating to a layered double hydroxide having a function of adsorbing heavy metals, a purification method, a method for producing a layered double hydroxide, a composite material containing the novel material, and its production The present invention relates to a method, an adsorbent, a purification facility, and a purification method of contaminated water.

Layered Double Hydroxide is typically a natural mineral, Hydrotalcite: Mg ₆ Al ₂ CO ₃ (OH) ₁₆ · 4H ₂ O, with the general formula [M ²⁺ _(1-x) M ^{3 +} _x (OH) ₂ ] ^{x +} [A ⁿ⁻ _{x / n} · yH ₂ O] ^x− (M: cation, A: n-valent anion). It has a crystal structure in which a trivalent cation is substituted in a hydroxide layer in which octahedrons in which OH ^- is coordinated to divalent cations are arranged in a plane. The amount of positive charge of the hydroxide layer is determined by the amount of substitution of trivalent cations, and an anion exists between the layers to neutralize this positive charge. It is known that the anion between the layers can be ion-exchanged, and the n-valent anion is composed of SO ₄ ²⁻ , Cl ⁻ , Br ^{− and the} like in addition to CO ₃ ²⁻ . Layered double hydroxides are used in various directions as inorganic layered substances having anion adsorption ability by ion exchange. In addition to Mg, the divalent cation is composed of Ca, Mn, Fe, Ni, Cu, Zn, etc. The trivalent cation is composed of Fe, Co, Mn, Cr, In, etc. in addition to Al. It is also known, and not only anions but also cations are composed of various types. The layered double hydroxide can also adsorb cations on the end face of the hydroxide layer.

  Non-patent documents 1 and 2 are known documents that refer to the use of the layered double hydroxide structure, adsorption capacity, water treatment, and the like.

Properties and applications of hydrotalcite (Shigeo Miyata: Bulletin of the smectite society, Vol. 6, No. 1, p12-26, 1996.) Application of hydrotalcite to water environment conservation and purification (Tomoto Kameda, Toshiaki Yoshioka, Yoshiaki Umezu, Akiyoshi Okwaki: The Chemical Times, 195, No.1, p10-16, 2005.)

As described above, since the layered double hydroxide has anion adsorption ability, its use as an adsorbent has been studied. In general layered double hydroxides having CO ₃ ^2- between layers, CO ₃ ^{2 -} there is a disadvantage that the low exchange of the other anions. Therefore, heating and baking in practical use, or by chemical treatment or the like, or excluding CO ₃ ^2- and interlayer, high exchangeable Cl ^- solves this by replacing the equal other anions, anion exchange adsorption capacity It is necessary to create and use a layered double hydroxide having a high thickness (see Non-Patent Documents 1 and 2).

However, the pretreatment that removes or replaces the CO ₃ ²⁻ between layers leads to high cost of the material. Therefore, the pretreatment is performed when the layered double hydroxide is used as a part of the highly functional material. It is limited and difficult to apply in the field of purification of contaminated soil and contaminated water, where demand for low-cost treatment is high. Therefore, a novel material that exhibits high anion adsorption ability without the pretreatment is desired.

In addition, layered double hydroxide is a kind of clay mineral and is in the form of fine particles, so it can be easily purified by mixing in addition to contaminated soil and water, but for example, ion exchange resin As in the water purification process, it is difficult to fill a predetermined container and allow the contaminated water to pass through to adsorb heavy metals of the contaminated water because clogging of fine particles occurs.
Another possible method is to arrange an adsorption layer of heavy metals on the lower ground of the contaminated soil and its surroundings to collect the heavy metals contained in the leachate from the contaminated soil and prevent groundwater contamination. In the case of the above method, it is essential to use a purification material having an adsorption effect. However, in the case of a liquid purification material, there is a runoff of itself, and in the case of a powder purification material, clogging of soil gaps occurs, resulting in partial clogging. Therefore, the effect of adsorbing heavy metals cannot be obtained because the permeability of the contaminated soil may be reduced and the leachate of the contaminated soil may travel through the soil gap without the purification material. Therefore, there is a need for a purification material that has no risk of material loss and has water permeability and can stably adsorb heavy metals by stably contacting contaminated water.

The present invention is proposed in view of the above-mentioned problems, and it is possible to achieve a high level of performance with respect to heavy metals contained in pollutants and contaminated water without performing treatment such as pretreatment for removing CO ₃ ^2- between layers of layered double hydroxides. New material capable of exhibiting a high level of adsorption capacity and high-level purification, purification method, method for producing layered double hydroxide, composite material containing the new material and method for producing the same, adsorbent, purification equipment and contamination It aims at providing the purification method of water.

The novel material of the present invention generates a divalent cation and a trivalent cation upon contact with water, and has a layered compound having an adsorption action of cation and anion within a pH range of 6 to 12.5. Spontaneously hydroxide [M ²⁺ _(1-x) M ³⁺ _x (OH) ₂ ] ^{x +} [A ^n- _{x / n} · yH ₂ O] ^x- (M: cation, A: anion) It is characterized by producing | generating. For example, divalent cations: Mg ²⁺ , Mn ²⁺ , Ca ²⁺ , Ni ²⁺ , Co ²⁺ , Cu ²⁺ , Zn ²⁺ , Fe ^2+, etc. Trivalent cation: Al ³⁺ , Mn ³⁺ , Co ³⁺ , Fe ^3+, etc., x range: layered double hydroxide [M ²⁺ _(1-x) M ³⁺ _x (OH) ₂ ] ^{x +} [A _{^{n- x / n · yH 2 O}} ] x- (M: a cation, a: anion) it is preferable that the new material that spontaneously generate.

Further, the novel material of the present invention is such that the divalent cation is magnesium, manganese, calcium, nickel, cobalt, copper, zinc or iron or a combination containing these, and the trivalent cation is aluminum, manganese, It is characterized in that iron, cobalt, or a combination containing these is produced upon contact with water. New material, any of magnesium, manganese, calcium, nickel, cobalt, copper, zinc, or iron as a component that generates a divalent cation, and any of aluminum, manganese, iron, or cobalt as a component that generates a trivalent cation A new material having the action of a layered double hydroxide adjusted to have an alkaline condition of pH 6 to 12.5 upon contact with water.
Examples of the divalent cation raw material that generates the divalent cation include slaked lime, quicklime, calcium carbonate, calcium silicate, magnesium oxide, magnesium hydroxide, manganese chloride tetrahydrate, manganese dioxide, and water. Nickel oxide, nickel chloride, cobalt chloride, cobalt sulfate, cobalt hydroxide, cobalt carbonate, cobalt hydroxide, cobalt monoxide, ferrous sulfate, zinc hydroxide, copper sulfate or copper hydroxide, magnesium, manganese, calcium, It is possible to use hydroxides, oxides or soluble salts such as nickel, cobalt, copper, zinc and iron, and mixtures, compounds and simple substances containing these.
Examples of the trivalent cation raw material that generates the trivalent cation include, for example, aluminum hydroxide, aluminum chloride, aluminum sulfate, manganese dioxide, ferrous sulfate, ferric sulfate, iron hydroxide, iron oxide, or four-three. It is possible to use hydroxides, oxides or soluble salts such as cobalt oxide, aluminum, manganese, iron and cobalt, and mixtures, compounds and simple substances containing these.

The divalent cation raw material and the trivalent cation raw material do not need to be in the target valence and ion state in the new material, and can be divalent cation by contact with water. And trivalent cations.
Examples of the pH adjuster for adjusting the pH to 6 to 12.5 include slaked lime, quicklime, calcium carbonate, calcium silicate, sodium silicate, potassium silicate, magnesium oxide, magnesium hydroxide, hydroxide, oxide Alternatively, soluble salts and mixtures and compounds containing them can be used.
The divalent cation raw material, the trivalent cation raw material, and the pH adjuster are within the range where the pH is 6 to 12.5 by contact with water. And the trivalent cation raw material can be mixed in an arbitrary weight ratio range. Moreover, when the water which contacts at the time of use of a new material, contaminant, contaminated water, etc. contain the component which comprises a new material, it is possible to adjust the component of a new material in view of the conditions.

  Further, the purification method of the present invention is a method in which the novel material of the present invention is brought into contact with contaminants or contaminated water, and the novel material adsorbs in the process of producing the layered double hydroxide or adsorbed after the production or both. To adsorb heavy metals in the pollutant or contaminated water. For example, by adding the above-mentioned new materials to pollutants or contaminated water, layered double hydroxides are produced in the purification target by the action of water, and in the contaminants, insolubilization due to adsorption of eluting heavy metals, Can reduce the concentration of heavy metals by adsorption of the contained heavy metals.

  Further, the method for producing a layered double hydroxide of the present invention comprises contacting the novel material of the present invention with a contaminant or contaminated water, and the adsorbing action when the novel material produces the layered double hydroxide, The layered double hydroxide is produced while adsorbing contaminants or heavy metals in contaminated water.

The composite material of the present invention is composed of a fibrous material and the novel material of the present invention supported on the fibrous material, and is characterized by having water permeability or permeability. The fibrous material is composed of, for example, component ratios of CaO: 0 to 50% (w / w), SiO ₂ : 0 to 100% (w / w), Al ₂ O ₃ : 0 to 100% (w / w) A fibrous material having a diameter of less than 1,000 μm, etc., for example, a length of 10 mm or more, a thickness of less than 1,000 μm, a straight hair shape and a curly hair shape, or both. Although it is preferable, it is appropriate within the scope of the gist of the present invention. Further, the degree of water permeability or permeability of the composite material is preferably such that the water permeability has a high water permeability of 10 ⁻⁵ cm / s or more.

Further, the composite material of the present invention can be used in place of the fibrous material instead of the fibrous material, such as activated carbon, zeolite, diatomaceous earth, pearlite. Porous material composed of, vermiculite, titanium, alumina, SUS, ceramic and silica porous inorganic materials, polystyrene, olefin, polyethylene, polypropylene, polycarbonate, PMMA, ethylene tetrafluoride, melamine, phenol, polyimide, polysulfone and formaldehyde It is possible to use a quality resin material or the like. These supporting materials also have the same effect as the fibrous material.
In addition, the method for producing a composite material of the present invention includes the novel material, CaO: 0 to 50% (w / w), SiO ₂ : 0 to 100% (w / w), Al ₂ O ₃ : 0 to 100 % (W / w) of the fibrous material having a diameter of less than 1,000 μm and water, and a new material: fibrous material: water = 1-5: 1-10: 0-10 weight ratio It is characterized by being manufactured by mixing.

In addition, the adsorbent of the present invention is characterized in that the composite material of the present invention is mixed substantially uniformly in sandy soil at a rate of 5 kg / m ³ or more.

  Further, the purification equipment of the present invention is stored in a water-impermeable box-shaped container with an open top surface or a cylindrical container with an open top and bottom surface, and the box-shaped container or the cylindrical container, and contaminated soil is arranged on the upper side. The composite material of the present invention or the adsorbent material of the present invention is provided. The said purification equipment is good also as a structure which provides the water collecting channel which collects the flowing water from the lower surface or part of side wall of a box-shaped container, or the flowing water part below a cylindrical container.

  The method for purifying contaminated water according to the present invention includes disposing the composite material of the present invention or the adsorbent material of the present invention on a flow path of contaminated water, and adsorbing heavy metal anions with the composite material or the adsorbent material. Features. For example, the composite material or adsorbent of the present invention is arranged on the ground or civil engineering structure around the pollutant so that the contaminated water that is leached from the pollutant passes through the composite material or adsorbent, and heavy metals Can be adsorbed by new materials, and heavy metal contamination can be prevented from diffusing into groundwater. Further, for example, a composite material is filled or laid in a purification container or a septic tank, and contaminated water containing heavy metals is allowed to pass through and come into contact with the composite material in the clarification container or septic tank, so that the heavy metals are adsorbed by a new material, Water concentration can be reduced by reducing the concentration.

  The invention disclosed in this specification includes, in addition to the configurations of each invention and each embodiment, those specified by changing these partial configurations to other configurations disclosed in this specification, or these configurations. To which other configurations disclosed in the present specification are added and specified, or those partial configurations deleted and specified to the extent that partial effects can be obtained are included. Moreover, the composite material or adsorbent of the present invention can be used for various applications where heavy metals such as arsenic, selenium, hexavalent chromium, phosphoric acid, antimony, lead, cadmium, and zinc are adsorbed.

The novel materials of the present invention can easily generate heavy metal anions such as arsenic and hexavalent chromium contained in the target pollutant or contaminated water by causing the production process to act on the pollutant or polluted water. It can be adsorbed (see FIG. 1). In addition, in order to form a layered double hydroxide in an environment containing heavy metals, divalent and trivalent such as lead and cadmium that can be a component of the layered double hydroxide hydroxide layer in the production process The purification action can be exerted by adsorbing and taking in the heavy metal cation to the hydroxide layer of the layered double hydroxide. That is, a high level of purification can be performed by exhibiting a high adsorbability for heavy metals contained in contaminants and contaminated water. Further, the structure having no CO ₃ ²⁻ between the layers eliminates the need for pretreatment for removing CO ₃ ²⁻ between the layers of the layered double hydroxide, thereby reducing the cost.

The composite material, adsorbent, and the like of the present invention have no fear of material loss and have water permeability, and can stably adsorb heavy metals by stably contacting contaminated water.
In addition, when contaminated water or contaminated water from leached water from contaminated soil is allowed to pass between the fibrous materials of the composite material or adsorbent material, the adsorbing action of heavy metals on the fibrous material while passing water continuously. And can adsorb heavy metals very efficiently under water-permeable conditions. For example, the composite material is mixed in the lower ground of the contaminated soil, the leachate from the contaminated soil is allowed to pass through the existing portion of the composite material as water in the ground, the heavy metals contained in the leachate are adsorbed, and It is possible to achieve groundwater conservation by preventing the diffusion of heavy metals.

An embodiment of a new material that spontaneously generates a layered double hydroxide capable of adsorbing heavy metals without the influence of CO ₃ ^2- between the layered double hydroxide layers, and adding the new material to the contaminant An embodiment in which heavy metals are adsorbed and insolubilized will be described including a comparison with a normal layered double hydroxide.

Embodiment of new material
The novel material of this embodiment is a novel powder material in which a soluble aluminum salt and a soluble magnesium salt are uniformly mixed at a weight ratio of 1: 1 to adjust the pH to 10, and the novel material is in contact with water. To elute soluble divalent cations and trivalent cations in the components, and the layered double hydroxide [M ²⁺ _(1-x) M ³⁺ _x (OH) ₂ ] ^{x +} [ A ^n- _{x / n} · yH ₂ O] ^x- (M: positive ion, A: negative ion) is spontaneously generated.

A novel powder material in which insoluble ash containing hexavalent chromium, arsenic and boron is used, and the soluble aluminum salt and the soluble magnesium salt are uniformly mixed at a weight ratio of 1: 1 to adjust the pH to 10, and Mg: Al = 3: 1 type hydrotalcite (Mg ₆ Al ₂ (OH) ₁₆ CO ₃ · 4 (H ₂ O)) as a comparative control of mold layered double hydroxide 5% (w / w) was added. After the addition, 50% (w / w) water of incinerated ash was uniformly mixed and kneaded. After sealed curing for 1 day, it was air-dried to obtain an analytical sample. The analysis sample was subjected to 2003 Ministry of the Environment Notification No. 18 dissolution test based on the Soil Contamination Countermeasures Law, and analyzed the pH of the test solution and the elution amount of hexavalent chromium, arsenic and boron by ICP-MS. In addition, the analysis sample was subjected to powder X-ray diffraction analysis to analyze the mineral composition.

  The results of the dissolution test are shown in Table 1. Incineration ash exceeds the environmental standard values for arsenic and boron, and exceeds the environmental standard values even after treatment with 5% (w / w) hydrotalcite. However, the elution amount is reduced to the detection limit or below the detection limit in the new material, and the insolubilizing effect by adding the new material is recognized. The result of the powder X-ray diffraction analysis is shown in FIG. In the powder X-ray diffraction line profile after the treatment of the new material, clear lamellar double hydroxide peaks not found in the incineration ash were obtained at around 11.8 ° and around 23.5 °, compared to the incineration ash before the treatment. . From the above, it is confirmed that layered double hydroxides are generated in the incinerated ash by adding new materials and insolubilize heavy metals.

  The above example explained an example of insolubilization of arsenic and boron by adding to incineration ash as a new material and its method of use, but it is the same for pollutants containing heavy metals such as contaminated soil and sludge as well as incineration ash It can be insolubilized, and other heavy metals such as hexavalent chromium, selenium, fluorine, lead, cadmium, zinc, etc. can be adsorbed and insolubilized as substances to be adsorbed. Moreover, since an effect | action expresses when water touches a new material, a new material can be similarly applied with respect to contaminated waters, such as a factory waste water and a muddy water.

[Embodiments of composite material, adsorbent and purification equipment]
Regarding the present invention, it is an embodiment of a water-permeable purification facility using a composite material having a high water permeability supported by a fibrous material, an adsorbent using the composite material, and the composite material adsorbing heavy metals. This will be explained based on this.

The composite material of this embodiment is composed of a fibrous material and a new material carried on the fibrous material, and has a water permeability of 10 ⁻⁵ cm / s or more. The fibrous material has a length of about 10 mm or more, a thickness of less than about 10 μm, and a curly shape. The composite material is a novel powder material in which a soluble aluminum salt and a soluble magnesium salt are uniformly mixed at a weight ratio of 1: 3 to adjust the pH to 10, CaO: about 40% (w / w) as a component, Compared to inorganic fibrous material with a diameter of less than 10 μm consisting of SiO ₂ : about 45% (w / w) and Al ₂ O ₃ : about 15% (w / w), new material: fibrous material: water = 2 : 2: 1 mixed by weight. Water was given to sprinkle during mixing. The new material reacts slightly with water and proceeds into layered double hydroxides. The resulting hydration reaction on the surface of the new material makes it easier for the surface of the new material to be electrically attracted to the surface of the inorganic fibrous material. It becomes easy to carry, and the new material is carried on the surface of the fibrous material by the mixing.

Furthermore, the adsorbent (adsorption layer) of the present embodiment was prepared by uniformly mixing the prepared composite material in sandy soil at a rate of 40 kg / m ³ and laying it to a thickness of 0.2 m. As shown in FIG. 3, the adsorbing layer is housed in a water-impermeable, box-shaped container having an open top surface to form a purification facility. The purifying equipment includes a flowing water portion provided on one side wall of the box-shaped container (a plurality of flowing water notches provided at the upper end of the side wall, a flowing hole formed in the side wall, a side wall having a lower height than the other side walls. A water collecting groove for collecting water flowing from an upper end surface or the like is provided at an outer position adjacent to the box-shaped container (an outer position adjacent to the adsorption layer), and the water collecting groove constitutes a water collecting channel.

  On the upper side of the adsorbent housed in the box-shaped container, contaminated soil was disposed. In this embodiment, the contaminated soil containing arsenic was embanked to a height of 0.7 m due to natural causes. The leachate of the contaminated soil flows to the lower adsorption layer, and the arsenic of the leachate is adsorbed by the composite material by passing through the adsorption layer. The leachate purified by the adsorption is guided to the water collecting groove through the water flow portion, and is recovered by flowing through the water collecting groove.

  Here, the arsenic concentration of the water purified by the adsorbent (adsorption layer) in FIG. 3 was analyzed by a hydride ICP emission spectrometer. In addition, as a comparative control, a construction in which the soil was laid without adding the composite material to sandy soil was prepared and compared. The result of the analysis is shown in FIG. Based on the analysis results of the embankment of contaminated soil, arsenic changed around 4 times the environmental standard value, but the water quality that passed through the adsorption layer mixed with new materials or composites remained below the environmental standard value of 0.01 mg / L for groundwater. The effect of purifying and preventing diffusion of arsenic, which is a heavy metal, was confirmed.

  In the above embodiment, as an example of the composite material and its method of use, it is mixed with sandy soil below the contaminated soil containing arsenic due to natural causes and laid as an adsorption layer, for example, preventing the diffusion of pollutants into the groundwater Although described, the present invention is not limited to this.

For example, hexavalent chromium, selenium, fluorine, lead, cadmium, zinc, etc. are appropriate as other heavy metals adsorbed by the composite material or adsorbent, and these substances can be purified by the same method as described above. It is. In addition, when the composite material is an adsorbent (adsorption layer), the mixing target is not limited to sandy soil, but may be other ground or civil engineering materials. In addition to mixing with soil and civil engineering materials, the composite material of the present invention fills containers and pits and allows polluted water to pass through the pollutant such as spring water containing drainage and heavy metals. Can be applied against water.
In addition, the new material used for the fibrous material in the above embodiment is a material in which a soluble aluminum salt and a soluble magnesium salt are uniformly mixed at a weight ratio of 1: 3 and adjusted to pH 10; Is in the range of pH 6 to 12.5 where the layered double hydroxide is formed, and divalent cation is magnesium, manganese, calcium, nickel, cobalt, copper, zinc, iron, trivalent cation. Any one or more of aluminum, manganese, iron, and cobalt can be included in any ratio.

  Moreover, it is possible to use a porous material having water permeability instead of the fibrous material. The material of the present invention can be made of, for example, an inorganic material (activated carbon, zeolite, diatomaceous earth, pearlite, vermiculite, titanium, alumina, SUS, ceramic, silica, etc.), and in addition to inorganic materials, organic fibers Or a porous material (polystyrene, olefin, polyethylene, polypropylene, polycarbonate, PMMA, ethylene tetrafluoride, melamine, phenol, polyimide, polysulfone, formaldehyde, or the like).

  In addition, when the new material cannot be supported only by water, an appropriate organic binder (starch, starch, cellulose, polyvinyl alcohol, polyvinyl pyrrolidone, vinyl acetate, acrylic for supporting the new material on the fibrous material) , Ethylene vinyl alcohol, urethane resin, carboxymethyl cellulose, suspension agent for vinyl chloride polymerization, vinyl carboxylate, vinyl acetate, polyvinyl alcohol and emulsions thereof) or inorganic binder (clay, ferrite, diatomaceous earth, calcium carbonate, kaolin, talc, etc.) , Gypsum, lime, cement, etc.).

  The present invention can be used, for example, for purification of contaminated water and soil and prevention of diffusion of pollutants.

A conceptual diagram of the reaction when a conventional layered double hydroxide containing CO ₃ ²⁻ between layers and a new material are introduced into pollutants or contaminated water, respectively. X-ray powder diffraction analysis profiles before and after incineration by adding new materials to incineration ash containing heavy metals. The schematic diagram of the purification equipment which laid the adsorption layer which mixed the composite material with the soil, and piled up the contaminated soil in the upper part. The graph which compares the arsenic density | concentration of the leachate which passed the adsorption layer, and the leachate which does not pass the adsorption layer.

Claims (9)

Contact with water produces a divalent cation and a trivalent cation, and a layered double hydroxide [M ²⁺ _(1-x) M ³⁺ _x ( OH) ₂ ] ^{x +} [A ⁿ⁻ _{x / n} · yH ₂ O] ^x− (M: cation, A: anion) is a novel material characterized by spontaneous generation. The divalent cation is magnesium, manganese, calcium, nickel, cobalt, copper, zinc, iron, or a combination containing these,
The novel material according to claim 1, wherein the trivalent cation is aluminum, manganese, iron, cobalt, or a combination containing these.   The new material according to claim 1 or 2 is brought into contact with contaminants or contaminated water, and the contaminants are adsorbed in the process of producing the layered double hydroxide, or the adsorbing action after the production, or both. Or the purification method characterized by adsorb | sucking heavy metals in contaminated water.   The new material according to claim 1 or 2 is brought into contact with a contaminant or contaminated water, and the heavy metal in the contaminant or contaminated water is adsorbed by an adsorption action when the new material generates the layered double hydroxide. However, the method for producing a layered double hydroxide, wherein the layered double hydroxide is produced. Fibrous material,
It is comprised with the novel material of Claim 1 or 2 carried by the said fibrous material,
A composite material having water permeability. A method for producing a composite material according to claim 5,
Wherein the new materials, CaO: 0~50% (w / w), SiO 2: 0~100% (w / w), Al 2 O 3: diameter consisting of component ratio of 0~100% (w / w) A composite material produced by mixing the fibrous material of less than 1,000 μm and water at a weight ratio of novel material: fibrous material: water = 1 to 5: 1 to 10: 0 to 10 Manufacturing method. An adsorbent characterized in that the composite material according to claim 5 is mixed substantially uniformly in sandy soil at a rate of 5 kg / m ³ or more. An impervious box-shaped container with an open top or a cylindrical container with an open top and bottom;
A purification equipment comprising the composite material according to claim 5 or the adsorbent according to claim 7, which is housed in the box-shaped container or the cylindrical container, and the contaminated soil is disposed on the upper side.   A method for purifying contaminated water, comprising disposing the composite material according to claim 5 or the adsorbent material according to claim 7 on a contaminated water flow path, and adsorbing heavy metals with the composite material or the adsorbent material.

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