CN113546604B

CN113546604B - Adsorption material

Info

Publication number: CN113546604B
Application number: CN202110392106.0A
Authority: CN
Inventors: 横山茂辉; 袋昭太; 松泽大起; 仓泽响
Original assignee: Japanese Fujita Co ltd
Current assignee: Japanese Fujita Co ltd
Priority date: 2020-04-23
Filing date: 2021-04-13
Publication date: 2023-11-03
Anticipated expiration: 2041-04-13
Also published as: JP2021171692A; CN113546604A

Abstract

The invention provides an adsorbent having excellent adsorption performance and uniform shape. The adsorbent contains porous carbide and iron, and has a substantially cylindrical shape having a long axis (D) and a height (H), wherein the ratio (H/D) of the height (H) to the long axis (D) is 0.5 to 5, and the long axis (D) is 1mm to 20 mm. The iron content may be 5% or more and 35% or less. The content of the organic carbon in the carbide may be 30% or more and 85% or less. The content of the organic carbon in the carbide may be 50% or more and 85% or less.

Description

Adsorption material

Technical Field

The present invention relates to an adsorbent material. And more particularly to an adsorbent material for adsorbing phosphorus.

Background

Technology is known in which carbon dioxide is artificially recovered and stored underground in order to reduce the amount of carbon dioxide in the atmosphere. For example, biomass (biomass) such as wood and crops can absorb carbon dioxide in the atmosphere, and the carbon dioxide can be fixed to the biomass as organic carbon. However, since these biomasses are organic, even if they are stored directly under the ground, they are decomposed and spoiled, and carbon dioxide is released again into the atmosphere. On the other hand, when the biomass is heated while blocking oxygen, oxygen atoms and hydrogen atoms are separated from each other, and carbide composed of carbon and ash can be produced. Since this carbide is a carbon block containing no glycans or amino acids decomposed by microorganisms, it is very stable in the environment (underground) and hardly decomposed. Carbonized biomass has been used in farmland since ancient times, and is also recognized as a soil improvement material in japan law (earth's power enhancement method), and therefore, carbon dioxide can be sequestered and stored underground as a result of fertilization of farmland and the like. In other words, the agricultural utilization of biomass carbides helps to reduce the amount of carbon dioxide in the atmosphere. However, considering the cost required to produce carbide and current carbon pricing, the soil improvement formula for using carbide only for soil is not matched to the production cost.

On the other hand, since carbide is porous, it is known that its surface area is very large. By utilizing the surface area, carbide can be used as an adsorbing material for various substances. For example, patent document 1 discloses a phosphorus recovery material using a carbide supporting calcium. By adsorbing phosphorus using such a phosphorus recovery material, water pollution due to phosphorus discharge into natural waters can be suppressed. Further, if the phosphorus recovery material having phosphorus adsorbed thereto is buried in an agricultural field, the crop can dissolve the phosphorus adsorbed to the phosphorus recovery material by the organic acid released from the roots. This phosphorus acts as a fertilizer for crops, and thus can increase the yield of farmlands where phosphorus recovery material is buried, or can grow high quality crops.

Thus, there is an increasing demand for carbides which not only improve the soil properties of the soil but also, for example, can suppress environmental pollution by adsorbing a substance or which can apply such a harmful substance to other uses.

(prior art literature)

(patent literature)

Patent document 1: japanese patent laid-open No. 2007-75706

Patent document 2: japanese patent laid-open No. 2020-11211

Disclosure of Invention

(problem to be solved by the invention)

However, in the phosphorus recovery material of patent document 1, a material containing a large amount of silicon such as rice husk or diatomaceous earth is required to be used. In the case of using a material containing a large amount of silicon, the production amount of the phosphorus recovery material is limited. In addition, the allowable amount of substances such as phosphorus that can be adsorbed is limited.

Patent document 2 describes an adsorbent made of an iron-containing carbide. Since the carbide has high conductivity, electron exchange can be rapidly performed between the carbide and iron attached to the pores provided in the carbide. Therefore, if an adsorbent made of an iron-containing carbide is placed in water, iron can be ionized to produce a hydroxide such as iron oxyhydroxide (FeOOH), and the hydroxide reacts with phosphate ions present in water to form iron phosphate, and the iron phosphate is adsorbed and fixed to the carbide. That is, the adsorbing material composed of the carbide containing iron can efficiently adsorb phosphorus by the above mechanism.

Such an adsorbent is generally used by packing it into a column (column). That is, the phosphorus-containing water or the like passes through the column, whereby the phosphorus is adsorbed by the adsorbent and removed. On the other hand, when using an adsorbent having phosphorus adsorbed thereon, it is necessary to take out the adsorbent from the column. However, if the shape of the adsorbent is not uniform, there is a problem in that it is difficult to take out the adsorbent from the column, such as the adsorbent sticking to the wall surface of the column. Further, since the adsorbent packed in the column is an adsorbent having a certain size or more, the adsorbent is screened, but if the adsorbent is not uniform in shape, there are many cases where the material that can be used as the adsorbent passes through the mesh of the screen, and there is a problem that the utilization rate of the adsorbent is lowered.

One of the embodiments of the present invention has been accomplished in view of the above problems, and an object thereof is to provide an adsorbent having excellent adsorption characteristics and a uniform shape.

(measures taken to solve the problems)

The adsorbent according to one embodiment of the present invention contains porous carbide and iron, is substantially cylindrical having a long axis (long diameter) D and a height H, and has a ratio (H/D) of the height H to the long axis D of 0.5 to 5, and the long axis D of 1mm to 20 mm.

The iron content may be 5% or more and 35% or less.

The content of the organic carbon in the carbide may be 30% or more and 85% or less. The content of the organic carbon in the carbide may be 50% or more and 85% or less.

At least a part of the organic carbon may be produced by calcining at least one selected from molasses, waste molasses, starch, dextrin, corn starch, rice bran, polyvinyl alcohol, pulp waste liquid, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenolic resin, and tar pitch.

The adsorption amount of phosphorus of the adsorbent may be 5mg-P/g or more.

(effects of the invention)

The adsorbent according to one embodiment of the present invention has not only excellent adsorption characteristics but also a certain uniform shape. Therefore, the adsorbent can be easily packed into or taken out of the column, and the adsorbent can be easily used in various applications. In addition, in the screening when selecting the adsorbent, the utilization efficiency of the adsorbent can be improved. Therefore, the yield in the screening of the adsorbent can be improved, and an inexpensive adsorbent can be provided.

Drawings

Fig. 1 is a schematic view of an adsorbent material according to one embodiment of the present invention.

Fig. 2 is a flowchart of a method for producing an adsorbent according to an embodiment of the present invention.

Fig. 3 is a diagram illustrating a method for producing an adsorbent according to one embodiment of the present invention.

(description of the reference numerals)

10: an adsorption material; 20: granulating; 100: a first carbide; 110: iron;

120: a second carbide; 200: carbide; 210: an iron compound; 220: organic adhesive

Detailed Description

Hereinafter, an adsorbent and a method for producing the adsorbent according to one embodiment of the present invention will be described with reference to the drawings. However, the adsorbent and the method of producing the adsorbent in one of the embodiments of the present invention may be implemented in a variety of different ways, and should not be construed as being limited to the descriptions of the examples shown below. In the drawings referred to in this embodiment, the same reference numerals are given to the same parts or parts having the same functions, or letters are added to the same parts or parts having the same functions, and overlapping descriptions are omitted.

[1. Structure of adsorbent 10 ]

The structure of the adsorbent 10 will be described with reference to fig. 1.

Fig. 1 is a schematic view of an adsorbent material 10 according to one embodiment of the present invention. As shown in fig. 1, the adsorbent material 10 includes a first carbide 100, iron 110, and a second carbide 120. In the adsorbing material 10, the first carbide 100 and the second carbide 120 may be the same carbide or different carbides. Details will be described later, but raw materials of the first carbide 100 and the second carbide 120 are different. Accordingly, for convenience, the first carbide 100 and the second carbide 120 are differently described below based on the difference of raw materials.

The adsorbent material 10 is in the form of so-called pellets (pellet). The details will be described later, but the adsorbent 10 is granulated and formed into granules. The shape of the adsorbent 10 is, for example, a substantially cylindrical shape, a substantially elliptic cylindrical shape, a substantially polygonal cylindrical shape, or the like, but is not limited thereto.

The substantially cylindrical shape is preferably a perfect cylinder shape, but is not limited thereto. The ratio (major axis/minor axis) of the major axis (major axis) to the minor axis (minor axis) of the substantially cylindrical circle is 1 to 5. On the other hand, a substantially columnar shape having a ratio of the major axis to the minor axis (major axis/minor axis) of more than 5 is regarded as a substantially elliptic columnar shape. In addition, the substantially cylindrical facing surfaces may not have the same dimensions. Further, the substantially cylindrical shape in this specification includes a substantially cylindrical shape with a partial missing portion.

The substantially polygonal columnar shape includes, for example, a triangular columnar shape, a quadrangular columnar shape, a pentagonal columnar shape, a hexagonal columnar shape, or the like. The generally polygonal columnar facing surfaces may not have the same dimensions. Further, the substantially polygonal columnar shape in this specification includes a substantially polygonal columnar shape in which a portion is missing.

The shape of the adsorbent 10 is substantially determined by the shape of the granulated substance 20 described later, but the height H (see fig. 1) of the adsorbent 10 is 1mm or more and 20mm or less, preferably 3mm or more and 15mm or less, and more preferably 6mm or more and 12mm or less. The major axis D (maximum diameter in the direction perpendicular to the height, see fig. 1) of the adsorbent 10 is 1mm to 20mm, preferably 2mm to 10mm, and more preferably 3mm to 8 mm. The size of the adsorbent 10 may be controlled during the manufacturing process of the adsorbent 10. Therefore, the size of the adsorbent 10 is preferably within the above range that is easy to use and has good adsorption effect.

The ratio (H/D) of the height H to the long axis D of the adsorbent 10 is 0.5 to 5, preferably 0.5 to 4, more preferably 0.5 to 3. When the ratio (H/D) of the height H to the long axis D of the adsorbent 10 is within the above range, the adsorbent 10 is excellent in adsorption effect, and the adsorbent 10 can be easily used in various applications.

The adsorbent 10 may be porous. That is, the first carbide 100 and the second carbide 120 may be porous. The adsorbent 10 may contain iron 110 in the porous materials of the first carbide 100 and the second carbide 120.

[2 ] Process for producing adsorbent 10 ]

A method for producing the adsorbent 10 according to one embodiment of the present invention will be described with reference to fig. 2 and 3.

Fig. 2 is a flowchart showing a method of manufacturing the adsorbent 10 according to one embodiment of the present invention. Fig. 3 is a diagram illustrating a method for producing the adsorbent 10 according to one embodiment of the present invention.

As shown in fig. 2, the method for producing the adsorbent 10 includes a mixing step (S110), a kneading step (S120), a granulating step (S130), and a calcining step (S140). Hereinafter, each step will be described.

[2-1. Mixing step (S110) ]

In the mixing step (S110), as shown in fig. 3 (a), the carbide 200 and the iron compound 210 are mixed.

The carbide 200 is, for example, charcoal, bamboo charcoal, white charcoal, black charcoal, wood dust charcoal, coconut shell charcoal, rice hull charcoal, or powdered charcoal. The carbide 200 can be produced by carbonizing an organic material such as living wood (including stump, conifer, bamboo, etc., wood-based waste material of woodland, waste material of wood manufacturing plant or wood processing plant (including sawdust, tree scraps, chips, and chippings), plant-based shell, building decomposed material, or wood-based waste material of furniture material.

Carbonization of the organic substance can be performed by heating the organic substance in an inert gas atmosphere such as nitrogen or argon, an oxygen-free atmosphere, a low oxygen atmosphere, a reducing atmosphere, or a reduced pressure atmosphere. In the case of carbonizing the organic matter under a reduced pressure atmosphere, the carbonization may be performed in a range of 10 ² Pa or more and 10 ⁵ Low vacuum state of Pa or less, 10 ^-1 Pa or more and 10 ² A medium vacuum state of Pa or less, 10 ^-5 Pa or above 10 ^-1 A high vacuum state of Pa or less, or 10 ^-5 And under ultra-high vacuum condition of Pa or below. In the case of carbonizing an organic material in a low-oxygen atmosphere, the carbonization may be performed at an oxygen concentration of 0.01% or more and 3% or less, preferably 0.1% or more and 2% or less. The heating temperature for carbonizing the organic material is 400 to 1200 ℃, preferably 500 to 1100 ℃, more preferably 600 to 1000 ℃, particularly preferably 600 to 900 ℃. The heating time is 10 minutes to 10 days, preferably 10 minutes to 5 hours.

Carbonization of the organic material can be performed by internal combustion or external heating using an intermittent open or closed type charcoal kiln, a continuous rotary kiln, a swinging carbonization furnace, a screw furnace, a heating chamber, or a capped heat-resistant container (crucible). The internal heat type is a carbonization furnace that ensures heat required for carbonization of a material, and can supply oxygen required for burning the material to carbonize an organic substance. The external heating type is a carbonization furnace that supplies heat required for carbonization from the outside, and can block oxygen to carbonize organic substances.

When the organic matter is heated under reducing conditions, during the heating (for example, about 280 ℃), the composition decomposition of the organic matter starts, and oxygen or hydrogen in the organic matter volatilizes as a gas such as carbon dioxide, carbon monoxide, hydrogen or hydrocarbon, and the organic matter changes into amorphous carbon having a large carbon content. Further heating is continued at high temperature, oxygen or hydrogen in the organic matter is further reduced, and carbide 200 composed of high purity fixed carbon and ash is generated. Since moisture or constituent components in the organic matter are desorbed as volatile gas or the like, the carbide 200 generated by carbonization of the organic matter becomes a porous material in which a plurality of continuous pores of different sizes are formed. Further, as the heating temperature increases, carbide 200 formed by carbonization has heat resistance (fire resistance), adsorptivity, or conductivity. Accordingly, the carbide 200 may be porous, or may have heat resistance (fire resistance), adsorptivity, or conductivity.

The iron compound 210 may be a divalent iron compound or a trivalent iron compound, and divalent and trivalent iron may also be present in combination. As the iron compound 210, iron oxide, iron chloride, iron nitrate, iron sulfate, iron acetate, iron oxalate, or the like can be used. Among them, as the iron compound 210, iron oxide which is stable in performance and inexpensive is preferable. Iron oxides are, for example, feO (wustite), fe ₂ O ₃ (Hematite or maghemite) or Fe ₃ O ₄ (magnetite) and the like. The iron compound 210 may be one compound or may contain a plurality of compounds.

In addition, a metal compound other than iron may be used instead of the iron compound 210. As the metal other than iron, for example, aluminum, vanadium, nickel, cobalt, manganese, magnesium, calcium, or an alloy thereof may be used.

The carbide 200 generally contains water, and the content of water varies depending on the kind of the carbide 200. Therefore, in calculating the mixing ratio of the carbide 200 and the iron compound 210, the amount of the solid component of the carbide 200 is taken as a reference. For example, in the case where 100g of the carbide 200 contains 5% of water, the amount of the solid component of the carbide 200 may be calculated as 100×0.95=95 (g).

The mixing ratio of the amount (α) of the solid component of the carbide 200 to the amount (β) of the iron compound is α: beta = 100:1 to 80, preferably α: beta = 100:10 to 50, more preferably α: beta = 100: 20-40. If the mixing ratio is within the above range, the carbide 200 and the iron compound 210 do not agglomerate, and the carbide 200 and the iron compound 210 are uniformly mixed.

When the carbide 200 and the iron compound 210 are mixed, the particle diameters of the carbide 200 and the iron compound 210 may be adjusted. By adjusting the particle diameters of the carbide 200 and the iron compound 210, the carbide 200 and the iron compound 210 can be uniformly mixed. The particle diameters of the carbide 200 and the iron compound 210 can be adjusted by crushing the carbide 200 or the iron compound 210. In particular, since the particle size of the carbide 200 is larger than that of the iron compound 210 in many cases, the carbide 200 may be crushed so that the particle size of the carbide 200 matches that of the iron compound 210.

In addition, the carbide 200 and the iron compound 210 may be crushed in a kneading step (S120) described later, but fine adjustment of the particle size is difficult in the kneading step (S120). Therefore, in the case of adjusting the particle diameters of the carbide 200 and the iron compound 210, it is preferable to adjust the particle diameters of the carbide 200 and the iron compound 210 in advance in the mixing step (S110).

The sizes of the carbide 200 and the iron compound 210 are not particularly limited, but the average particle size of the carbide 200 is preferably 1 μm or more and 50mm or less, the average particle size of the iron oxide is preferably 1 μm or more and 10mm or less, and the average particle size of the carbide 200 is preferably 5 μm or more and 2mm or less, and the average particle size of the iron oxide is preferably 1 μm or more and 1mm or less. If the sizes of the carbide 200 and the iron compound 210 are within the above-described range, not only the carbide 200 and the iron compound 210 can be uniformly mixed, but also the organic binder 220 can be attached to the surfaces of the carbide 200 and the iron compound 210 in a kneading step described later, thereby integrating the carbide 200 and the iron compound 210.

In the mixture of the carbide 200 and the iron compound 210, a certain amount of water may be added. By adding water, dust generation in the mixing step (S110) can be prevented, and the carbide 200 and the iron compound 210 can be uniformly kneaded in the kneading step (S120) described later.

Through the above-described mixing step (S110), a mixture of the carbide 200 and the iron compound 210 is produced.

[2-2. Mixing step (S120) ]

In the kneading step (S120), as shown in fig. 3 (B), an organic binder 220 is added to the mixture (carbide 200 and iron compound 210) and kneaded to produce a paste.

Examples of the organic binder 220 include molasses, waste molasses, starch, dextrin, corn starch, rice bran, polyvinyl alcohol, pulp waste liquid, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenolic resin, and tar pitch. The organic binder 220 may contain one material or a plurality of materials. In particular, molasses or waste molasses is preferable as the organic binder 220. Molasses has a large solid content, and therefore, the paste is easily coagulated. Further, since the molasses contains a large amount of carbon components, the granulated product can be efficiently reduced in the calcination step (S140) described later. In addition, molasses is inexpensive and has little harmful components, so that the production cost of the adsorbent can be suppressed, and the adsorbent produced can be used as a safe fertilizer.

The viscosity of the organic adhesive 220 can be adjusted as needed. For example, water or an organic solvent may be added to the organic adhesive 220 to adjust the viscosity of the organic adhesive 220. If the viscosity of the organic binder 220 is too high, kneading becomes difficult. If the viscosity of the organic binder 220 is too low, the viscosity of the paste must be adjusted before the granulation step (S130) to be described later. The viscosity of the paste may be adjusted by evaporating the added water or organic solvent, but the process of evaporating the water or organic solvent is required, and the carbide 200 and the iron compound 210 are agglomerated by the evaporation of the water or organic solvent, so that the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 is reduced. Therefore, the viscosity of the organic binder 220 is preferably adjusted before kneading with the mixture.

The amount of the organic binder 220 to be added is also based on the amount of the solid content of the carbide 200. The ratio of the amount (α) of the solid component of the carbide 200 to the amount (γ) of the solid component of the organic binder 220 is α: γ=100: 10 to 1000, preferably α: γ=100: 100 to 500, more preferably α: γ=100: 100-300.

In the kneading step (S120), the parameters that determine the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 are not only the mixture ratio of the mixture and the organic binder 220. The dispersibility in the mixing step (S110) may be controlled by parameters such as a kneading temperature and a kneading time of a kneader. Therefore, the mixer will be described below.

A mixer may be used to mix the mixture and the organic-based binder 220. As the kneading machine, for example, a single-screw kneading machine, a twin-screw kneading machine, a kneading roll (mixing roll), a kneader (kneader), a Banbury mixer, or the like can be used.

Further, a kneader having a mixing function may be used. In this case, the mixing step (S110) and the kneading step (S120) may be continuously performed. For example, carbide 200 and iron compound 210 are charged into a mixer and mixed. Subsequently, the organic binder 220 is put into a mixer and mixed with the mixture. The carbide 200, the iron compound 210 and the organic binder 220 may be added together in a kneader to mix and knead, but the carbide 200 and the iron compound 210 are likely to aggregate and bubbles are likely to be generated. Therefore, it is preferable to perform the mixing step (S110) and the kneading step (S120) separately. In the kneading step (S120), a kneading machine is used to add a fixed amount of the organic binder 220 to the mixture at a constant rate.

The kneading temperature may be arbitrarily set, but is not lower than 0℃and not higher than 50℃and preferably not lower than 10℃and not higher than 40 ℃. The kneading time is preferably 1 second to 1 hour, more preferably 1 minute to 30 minutes, and still more preferably 1 minute to 15 minutes. By setting the parameters of the kneading step (S120) in the above-described ranges, the dispersibility of the carbide 200 and the iron compound 210 in the organic binder 220 can be optimized.

A paste in which carbide 200 and iron compound 210 are dispersed in organic binder 220 is produced by the kneading step (S120).

[2-3 granulation step (S130) ]

In the granulating step (S130), as shown in fig. 3 (C), the paste is granulated to produce a granulated product 20 containing the carbide 200, the iron compound 210, and the organic binder 220.

The generation of the granulated substance 20 may be performed using a granulator. As the granulator, for example, a compression granulator, an extrusion granulator, a roll granulator, a blade granulator, a melt granulator, a spray granulator, or the like can be used. For the production of the substantially columnar granulated substance 20, an extrusion granulator is preferably used. Here, generation of the pellet 20 using an extrusion type pelletizer will be described.

The extrusion granulator extrudes a paste formed into a predetermined shape from a die (die) mounted thereon. The extruded paste is cut into a predetermined length to produce pellets 20 having a pellet shape with the extrusion direction being the height direction. By adjusting the cutting speed (rotational speed in the rotary cutting method) of the extrusion granulator, the length (height of the pellet shape) of the granulated material 20 can be adjusted. Further, by adjusting the opening diameter of the die, the axis (diameter when the cross-sectional shape is circular) of the granulated substance 20 can be adjusted. Therefore, by using the extrusion granulator, it is possible to produce the granulated product 20 having a particle shape (for example, a substantially cylindrical shape) whose size is controlled.

The length of the granulated material 20 is 1mm to 20mm, preferably 3mm to 15mm, more preferably 6mm to 12 mm. The diameter of the granulated material 20 is 1mm to 20mm, preferably 2mm to 10mm, more preferably 3mm to 8 mm. If the size of the granulated substance 20 is within the above range, the iron compound 210 can be sufficiently reduced in the calcination step (S140), and therefore the adsorption effect of the adsorbent 10 can be improved.

The cross-sectional shape of pellet 20 is not limited to circular. The cross-sectional shape of the granulated material can also be changed by changing the opening shape of the die. The cross-sectional shape of the pellets may be, for example, elliptical or polygonal. That is, the granulated substance 20 may have a particle shape of not only a cylinder but also an elliptic cylinder or a polygonal cylinder.

In the granulation step (S130), an auxiliary agent may be added to stabilize the particle shape of the granulated substance 20. As the auxiliary agent, for example, an organic resin such as a polyester resin, an acrylic resin, a phenolic resin, an epoxy resin, a silicone resin, a polyimide resin, a polystyrene resin, or a polyurethane resin can be used. In the calcination step (S140) described later, these organic resins are carbonized, and the carbide thereof can also function as an adsorbent.

Through the granulation step (S130), the granulated product 20 containing the carbide 200, the iron compound 210, and the organic binder 220 can be produced.

[2-4 calcination step (S140) ]

In the calcination step (S140), the granulated substance 20 is calcined to produce the adsorbent 10.

Calcination of the pellets 20 is performed by heating the pellets 20 under a reducing atmosphere. The granulated substance 20 contains an organic binder 220. When the organic binder 220 is heated, a reducing gas such as carbon monoxide gas, hydrogen sulfide gas, sulfur dioxide gas, or hydrocarbon gas is generated. Therefore, the reducing gas generated from the granulated substance 20 can be used to form the reducing atmosphere without additionally introducing the reducing gas. That is, the iron compound 210 may be reduced using the reducing gas generated from the granulated substance 20. Further, since the reducing gas can be generated in the interior of the granulated substance 20, the iron compound 210 in the interior of the granulated substance 20 can be sufficiently reduced. Further, the iron compound 210 is reduced to the iron 110 by the reducing gas from the organic binder 220 around the iron compound 210, whereby the iron 110 of the adsorbent 10 after calcination has a structure contained in the porous material of the second carbide 120. Therefore, the adsorption amount of the adsorbent 10 can be increased.

In addition, from the viewpoint of explosiveness and combustibility, there are many reducing gases that are difficult to handle. Therefore, the inert gas may be contained in the calcination of the granulated material 20 in order to dilute and discharge the generated reducing gas. As the inert gas, for example, nitrogen gas, argon gas, or the like can be used. In the case of using an inert gas, for example, nitrogen may be circulated so that the concentration of carbon monoxide in the calciner is 1% or more and 20% or less.

In addition, a reducing gas such as carbon monoxide gas, hydrogen sulfide gas, sulfur dioxide gas, hydrocarbon gas, or a mixed gas thereof may be used as well as the reducing gas generated by the organic binder 220 to form a reducing atmosphere. However, even in this case, the amount of the reducing gas can be reduced as compared with the conventional method for producing the adsorbent.

The heating temperature for calcining the granulated substance 20 is 400 ℃ to 1200 ℃, preferably 400 ℃ to 900 ℃, and more preferably 700 ℃ to 900 ℃. The heating time is 1 minute or more and 10 hours or less, preferably 10 minutes or more and 5 hours or less. In the method for producing the adsorbent 10 according to the present embodiment, the iron compound 210 can be reduced using the reducing gas generated from the organic binder 220, so that the heating temperature can be reduced or the heating time can be shortened as compared with the usual method for producing the adsorbent.

By calcining the granulated substance 20, the carbide 200 changes to the first carbide 100, the iron compound 210 changes to the iron 110, and the organic binder 220 changes to the second carbide 120.

Through the above calcination step (S140), the adsorbent 10 containing the iron 110 is produced.

As described above, although the first carbide 100 and the second carbide 120 contained in the produced adsorbent 10 are distinguished from each other based on the difference in the raw materials for convenience of explanation, the first carbide 100 and the second carbide 120 are both carbides (are different in nature from the carbide 200), and the difference may not be explicitly made in the adsorbent 10. In other words, the adsorbent material 10 can be said to contain iron carbides. However, the adsorbent 10 has different properties from those of conventional iron-containing carbides, although the mechanism is not clear, unlike the conventional iron-containing carbide production method.

[2-5. Evaluation of adsorbent 10 ]

The adsorbent 10 of the present invention produced by the above-described production method is excellent in adsorption characteristics, and is reduced in elution of iron. The adsorption characteristics of the adsorbent 10 can be evaluated by, for example, the following measurement.

[2-5-1. Adsorption amount of phosphorus ]

The adsorbent 10 of the present embodiment can adsorb phosphorus, arsenic, lead, or the like. Among them, the adsorbent 10 is excellent in the adsorptivity of phosphorus. The adsorption of phosphorus in the adsorbent material 10 can be evaluated by a batch sampling test (batch testing) test. The batch sampling test is a method of calculating the adsorption amount of phosphorus from the concentration of the added phosphorus solution and the concentration difference of the supernatant after the reaction. The phosphorus solution is prepared by mixing potassium dihydrogen phosphate (KH ₂ PO ₄ ) Is dissolved in water. In the following examples, the amount of P relative to 1L of water was used as a description of the concentration of the phosphorus solution. That is, the concentration of a phosphorus solution in which 200mg of P was dissolved in 1L of water was described as 200mg/L. The amount of phosphorus adsorbed by the adsorbent 10 is described as the amount of phosphorus adsorbed per 1g of adsorbent (amount of phosphorus adsorbed (mg-P)/1 g of adsorbent).

[2-5-2. Specific surface area ]

The specific surface area is a surface area per unit amount, and is one of important parameters of the porous property. The specific surface area is related to the surface structure of the adsorbent 10, and can be said to be one of the parameters determining the adsorption characteristics. The specific surface area of the adsorbent 10 can be measured, for example, by a gas adsorption method (BET method) based on the BET formula.

In the BET method, the specific surface area of a sample (surface area per 1g of sample) can be calculated from the measurement of adsorption of gas. Specifically, in the BET method, the specific surface area is determined from the adsorption isotherm. That is, the adsorption amount of the adsorbed gas can be determined based on the BET formula, and the specific surface area can be determined by multiplying the area occupied by one molecule of the adsorbed gas on the surface. As the adsorption gas, for example, nitrogen gas, argon gas, krypton gas, carbon monoxide gas, or carbon dioxide gas can be used, and the adsorption amount can be measured according to the change in pressure or volume of the adsorbed gas. As for a specific measurement by the BET method, for example, as a pretreatment, vacuum degassing is performed at a temperature of 120 ℃ and nitrogen gas is adsorbed as an adsorption gas, and the specific surface area is calculated according to the BET formula.

The specific surface area described in the present specification is typically a specific surface area measured by the BET method using nitrogen as the adsorption gas, but may be a specific surface area measured by a method other than the BET method.

The specific surface area of the adsorbent 10 was 100m ² Above/g and 500m ² Preferably 100m or less per gram ² Above/g and 400m ² Preferably less than or equal to/g, more preferably 150m ² Above/g and 400m ² And/g or less. If the specific surface area of the adsorbent 10 is too small, a sufficient adsorption amount cannot be ensured, and thus the adsorption characteristics of the adsorbent 10 are degraded. On the other hand, if the specific surface area of the adsorbent 10 is excessively large, the density decreases, and thus the strength of the adsorbent 10 decreases. That is, the adsorbent 10 cannot maintain a certain shape and becomes brittle. Therefore, the specific surface area of the adsorbent 10 is preferably within the above-described range.

[2-5-3. Total pore volume ]

The total pore volume and the specific surface area are one of the important parameters of the porosity. The total pore volume is related to the adsorption amount of the adsorbent 10, and can be said to be one of the parameters determining the adsorption characteristics of the adsorbent 10. The total pore volume of the adsorbent 10 is the sum of pore volumes calculated from the pore volume distribution, which represents the pore diameter and pore volume of the adsorbent 10.

The fine pores may be classified into large pores (d >50 nm), medium pores (2 nm. Ltoreq.d.ltoreq.50 nm) or fine pores (d <2 nm), for example, according to the fine pore diameter d. Further, the pore diameters d of the respective pores may be typically measured by measuring macropores by a mercury porosimetry method based on a Washburn formula, measuring mesopores by a gas adsorption method (BJH method) based on a BJH formula, and measuring micropores by a gas adsorption method (HK method) based on an HK formula, but are not limited thereto.

In the mercury porosimetry, the pore diameter d may be calculated from the pressure of mercury injected into a sample based on the Washburn formula. In addition, in the gas adsorption method, the pore diameter d may be calculated from the pressure of the gas injected into the sample based on the BJH formula, HK formula, or the like. Accordingly, the pressure of the injected mercury or gas is changed to measure the adsorption amount of the sample, thereby obtaining a pore volume distribution showing the pore volume corresponding to the pore diameter d.

In the present specification, the accumulation of pore volumes in the range of 7.5nm to 110000nm inclusive of the pore diameter d is referred to as the total pore volume.

The total pore volume of the adsorbent material 10 was 1000mm ³ Over/g and 3000mm ³ Preferably 1000mm or less per gram ³ Above/g and 2700mm ³ Preferably 1000mm or less per gram ³ Over/g and 2500mm ³ And/g or less. If the total pore volume of the adsorbent 10 is too small, a sufficient adsorption amount cannot be ensured, and thus the adsorption characteristics of the adsorbent 10 are degraded. On the other hand, if the total pore volume of the adsorbent 10 is too large, the specific surface area decreases, and thus the adsorption characteristics of the adsorbent 10 decrease. Accordingly, the total pore volume of the adsorbent 10 is preferably within the above range.

[2-5-4. Iron content ]

The adsorption material 10 contains iron 110 in the carbide, and thus the adsorption amount is greatly increased as compared with conventional activated carbon. Therefore, the content of the iron 110 in the adsorbent 10 is related to the adsorption amount, and can be said to be one of the parameters determining the adsorption characteristics of the adsorbent 10. The amount of iron 110 contained in the adsorbent 10 can be measured, for example, using inductively coupled plasma mass spectrometry (ICP-MS).

ICP-MS is a method of ionizing an element contained in a sample using an argon plasma as an ion source, and separating and detecting ions based on mass-to-charge ratio. The element may be specified based on the mass-to-charge ratio of the detected ions, and the amount of the element may be determined by counting the detected ions.

The content of iron 110 in the adsorbent 10 is the ratio of the amount of iron 110 to the amount of the adsorbent 10. The content of the iron 110 in the adsorbent 10 can be calculated from the amount of the iron 110 measured by the ICP-MS and the amount of the adsorbent 10 used in the measurement.

The iron 110 content of the adsorbent 10 is 5% to 35%, preferably 5% to 30%, more preferably 5% to 25%. If the iron content of the adsorbent 10 is too small, the effect of iron cannot be exhibited, and thus the adsorption characteristics of the adsorbent 10 are degraded. On the other hand, if the iron content of the adsorbent 10 is too high, iron will be eluted when adsorbing phosphorus. Therefore, the iron content of the adsorbent 10 is preferably within the above range.

[2-5-5. Organic carbon content ]

In the above-described method for producing the adsorbent 10, the organic binder 220 can be kneaded to stably produce the granulated product 20 in the form of particles. The iron compound 210 can be sufficiently reduced to the iron 110 by the reducing gas generated from the organic binder 220 of the granulated material 20. Therefore, the organic binder 220 is a very important material in the production of the adsorbent 10. Since the organic binder 220 is changed to the second carbide 120 through the calcination process (S140), it is difficult to directly quantify the organic binder 220 by measurement of the adsorbent 10. However, the present inventors have found that the content of organic carbon contained in the carbide of the adsorbent 10 is related to the adsorption characteristics of the adsorbent 10. The mechanism of this association is not necessarily clear, but it is assumed that the organic carbon contained in the carbide of the adsorbent 10 is the second carbide 120. Therefore, by measuring the content of the organic carbon contained in the carbide of the adsorbent 10, the content of the second carbide 120 contained in the carbide of the adsorbent 10 can be obtained, and the adsorbent 10 can be specified to be manufactured using the organic binder 220. In this regard, the content of the organic carbon contained in the carbide of the adsorbent 10 can be said to be one of the parameters that determine the adsorption characteristics of the adsorbent 10.

The content of organic carbon contained in the carbide of the adsorbent material 10 can be calculated by subtracting the content of inorganic carbon from the content of total carbon. The total carbon content may be calculated, for example, based on the amount of carbon dioxide produced by burning the sample. The inorganic carbon content can be calculated based on, for example, the amount of carbon dioxide released from carbonate or the like by heating the sample while making the sample acidic. The combustion temperature at the time of measuring the total carbon content is preferably higher than the calcination temperature in the calcination step (S140). For example, if the calcination temperature in the calcination step (S140) is 850 ℃, the combustion temperature at the time of measuring the total carbon content may be 900 ℃. The heating temperature for measuring the inorganic carbon content is preferably lower than the calcination temperature in the calcination step (S140). The heating temperature for determining the inorganic carbon content is, for example, 200 ℃. In addition, the content of organic carbon may be calculated by measuring the content of total carbon and the content of inorganic carbon using a total organic carbon analyzer.

The content of organic carbon in the carbide of the adsorbent 10 is a ratio of the amount of organic carbon to the amount of carbide of the adsorbent 10. The content of organic carbon in the carbide of the adsorbent 10 can be calculated from the calculated content of organic carbon and the measured content of total carbon.

The content of organic carbon in the carbide of the adsorbent 10 is 30% or more and 85% or less, preferably 30% or more and 75% or less, and more preferably 35% or more and 70% or less.

[2-5-6. Major axis (major diameter) D and height H ]

The adsorbent material 10 may be photographed using an optical Microscope (Microscope) or a Scanning Electron Microscope (SEM), and the long axis D and the height H of the adsorbent material 10 may be determined using image software. In addition, the ratio (H/D) of the height H to the long axis D may be calculated using the measured long axis D and the height H.

As described above, the adsorbent 10 according to the embodiment of the present invention does not use special manufacturing equipment, and therefore can suppress manufacturing costs. The adsorbent 10 has different parameters and excellent adsorption characteristics from those of conventional adsorbents.

[ example ]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples.

Example 1

300g of amorphous charcoal as carbide and 83g of iron oxide were mixed for 3 minutes to obtain a mixture. Further, the moisture content of charcoal was 7.5%, and the solid content of charcoal was 300×92.5% = 277.5g. Thus, the ratio of the amount of solid components of charcoal to the amount of iron oxide was 277.5:83 =100: 30.

next, the mixture was put into a kneader (manufactured by Dalton (DALTON CORPORATION), model: KDRJ-10) and 500g of molasses was added thereto at ordinary temperature for 2 minutes, followed by kneading for 30 minutes to obtain a paste. The moisture content of the waste molasses was 30%, and the solid content of the waste molasses was 500×70.0% =350.0 g. The content ratio of the solid component amount of charcoal to the solid component amount of waste molasses was 277.5:350 =100: 126.1.

next, the paste was fed into a granulator (manufactured by Dalton, co., ltd.: F-5) to obtain granules having a diameter of 6mm and a height of 9mm in the form of granules at a rotation speed of 112 rpm.

Next, 50g of the obtained pellets were calcined at 750 ℃ for 3 hours under a nitrogen atmosphere using a two-wire three-zone tubular furnace unit (manufactured by Asahi physical and chemical manufacturing, co.) equipped with a quartz tube, to obtain 25g of adsorbent a.

The amount of phosphorus adsorbed by the adsorbent a was evaluated using a batch method. To 200mg/L of 50ml of phosphorus solution was added 0.1g of adsorbent material A, and the mixture was shaken horizontally at 23℃and 100rpm until reaching an equilibrium concentration, followed by filtration. The adsorption amount of phosphorus of the adsorbent material A calculated by analyzing the phosphorus concentration of the filtrate by molybdenum blue spectrophotometry was 27.2 (mg-P/g). Further, after the evaluation of the amount of phosphorus adsorbed, no disintegration of the adsorbent a was observed, and it was found that the adsorbent a had high strength in water. Further, the amount of iron eluted was 9.4ppm, and it was found that the amount of iron eluted from the adsorbent A was reduced.

< example two >

24g of adsorbent B was obtained under the same conditions as in example one, except that the calcination temperature was 800 ℃.

The amount of phosphorus adsorbed by the adsorbent B was evaluated under the same conditions as in example one. The adsorption amount of phosphorus of the adsorbent B was 37.9 (mg-P/g). Further, after the evaluation of the amount of phosphorus adsorbed, no disintegration of the adsorbent B was observed, and it was found that the adsorbent B had high strength in water. Further, the amount of iron eluted was 10.4ppm, and it was found that the amount of iron eluted from the adsorbent B was reduced.

Example III

22g of adsorbent C was obtained under the same conditions as in example one, except that the calcination temperature was 850 ℃.

The amount of phosphorus adsorbed by the adsorbent C was evaluated under the same conditions as in example one. The adsorption amount of phosphorus of the adsorbent C was 39.2 (mg-P/g). Further, after the evaluation of the amount of phosphorus adsorbed, no disintegration of the adsorbent C was observed, and it was found that the adsorbent C had high strength in water. Further, the amount of iron eluted was 9.8ppm, and it was found that the amount of iron eluted from the adsorbent C was reduced.

Comparative example

To confirm the effect of the adsorbent 10 of the present embodiment, the same evaluations as those of examples one to three were performed using commercially available activated carbon as an example of a conventional adsorbent. Specifically, the adsorption amount of phosphorus of activated carbon was evaluated using a batch method. A phosphorus solution of 0.5 g/200 mg/L (250 ml) of activated carbon (graininess WH2x manufactured by Osaka gas chemical Co., ltd.) was used. The adsorption amount of phosphorus of the activated carbon was 3.5 (mg-P/g).

Based on the above, it is apparent that the adsorption amount of phosphorus of the adsorbent 10 of the present embodiment is greatly increased by comparing the adsorbents a to C obtained in examples one to three with the activated carbon of the comparative example.

In order to compare the differences in properties between the adsorbents a to C obtained in examples one to three and the activated carbon of the comparative example, the specific surface area, total pore volume, iron content, and organic carbon content of each of the adsorbents a to C and the activated carbon were evaluated.

As a measurement of the specific surface area, a full-automatic specific surface area measuring apparatus (model: HM model-1201) manufactured by mountain Co., ltd was used.

The pore diameter distribution was measured using a fully automatic pore diameter distribution measuring apparatus (model: poreMaster 33P) manufactured by Kang Da (Quantachrome). The total pore diameter volume is obtained by integrating pore diameter volumes having pore diameters in the range of 7.5nm to 110000nm in the measured pore diameter distribution.

Regarding the measurement of the iron content, the adsorption material was subjected to a heating treatment at 100℃for 15 minutes in a 10% hydrochloric acid solution at 100℃and the iron content of the adsorption material was measured by ICP-MS. The iron content in the adsorbent was calculated from the amount of adsorbent used in the measurement and the measured iron content.

The organic carbon content was measured using a total organic carbon analyzer manufactured by Shimadzu corporation. Further, the content of the organic carbon relative to the carbide of the adsorbent was calculated based on the measured content of the organic carbon and the total carbon content.

Table 1 shows the evaluation results of the adsorbent materials a to C and activated carbon.

[ Table 1 ]

As is clear from table 1, when the calcination temperature was changed, the iron content and the organic carbon content of the adsorbent were changed. That is, if the calcination temperature is high, the iron content increases and the organic carbon content decreases. In addition, it is found that the content of organic carbon in the carbide of the adsorbent a to C is smaller than that of the activated carbon. It is presumed that the adsorption amount of phosphorus is greatly increased because the adsorbents a to C have such properties.

Further, the shapes of four samples (sample one to sample four) before screening in the adsorbent a obtained in example one were measured. Table 2 shows the measurement results of the shapes of the four samples.

[ Table 2 ]

	D(mm)	H(mm)	H/D
				Sample one	5.29	9.37	1.8
Sample two	5.07	6.48	1.3
				Sample three	3.32	7.5	2.3
Sample four	3.31	4.47	1.4

Samples one to four were all substantially cylindrical, although partially defective. The long axis D of each of the first to fourth samples is in the range of 1mm to 20 mm. The ratio (H/D) of the height H to the long axis D of each of the first to fourth samples is 0.5 to 5. It is found that samples one to four are adsorbent materials which are controlled to have a certain size even after calcination. Therefore, it is found that the adsorbent a is easily used as the adsorbent.

Claims

1. An adsorbent material, comprising: porous carbide; the iron is used to produce a metal alloy,

the adsorbent material is generally cylindrical having a long axis (D) and a height (H), wherein,

the ratio (H/D) of the height (H) to the long axis (D) is 0.5 to 5,

the long axis (D) is 1mm or more and 20mm or less,

the iron content is 5% to 35%,

the content of organic carbon in the carbide is 30% to 85%,

specific surface area of 100m ² Above/g and 500m ² The ratio of the total amount of the components per gram is less than or equal to,

the total pore volume is 1000mm ³ Over/g and 3000mm ³ And/g or less.

2. The adsorbent material of claim 1, wherein,

at least a part of the organic carbon is produced by calcining at least one selected from molasses, waste molasses, starch, dextrin, corn starch, rice bran, polyvinyl alcohol, pulp waste liquid, lignin sulfonate, carboxymethyl cellulose, hydroxypropyl methyl cellulose, sodium alginate, phenolic resin, and tar pitch.

3. The adsorbent material of claim 1, wherein,

the content of organic carbon in the carbide is 50% to 85%.

4. The adsorbent material of claim 3, wherein,

5. The adsorbent material of claim 1, wherein,

the adsorption quantity of phosphorus is more than 5 mg-P/g.