Adsorbing material, fertilizer production method, and fertilizer

Abstract

To provide: an adsorbing material which is capable of adsorbing phosphorus and nitrogen in a solution such as sewage sludge to collect them; a fertilizer production method; and a fertilizer.SOLUTION: An adsorbing material contains 40 to 60 pts.mass of charcoal, 20 to 30 pts.mass of iron, 10 to 30 pts.mass of a zeolite, and 1 to 10 pts.mass of citric acid and adsorbs phosphorus and / or nitrogen in an aqueous solution. In a fertilizer production method, the adsorbing material is caused to be present in a solution containing phosphorus and / or nitrogen and the adsorbing material having the phosphorus and / or the nitrogen adsorbed thereon is separated from the solution to obtain a fertilizer. The adsorbing material having the phosphorus and / or the nitrogen adsorbed thereon can be utilized as the fertilizer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adsorbent, a method for manufacturing a fertilizer, and a fertilizer.

Background Art

[0002] In Japan, most of the phosphorus and nitrogen, which are the main raw materials of chemical fertilizers, are imported. In particular, phosphorus is 100% dependent on imports. Due to the stagnation of imports and fluctuations in exchange rates, the securing of these raw materials is in an unstable situation, and a stable supply of fertilizer raw materials is demanded. Under these circumstances, since sewage sludge contains resources such as phosphorus and nitrogen, attempts have been made to recover phosphorus and nitrogen in sewage sludge and use them as fertilizer raw materials.

[0003] As methods for recovering phosphorus and the like, in addition to the HAP (hydroxyapatite) method, the MAP (magnesium ammonium phosphate) method, etc., methods using various adsorbents are known. For example, as in Patent Document 1, an adsorbent in which an iron compound is held on a ceramic substrate such as zeolite is known. Also, as in Patent Document 2, a method using a mixed packed bed of granular zeolite and granular activated alumina is known. Further, as in Patent Document 3, a method using hydrated iron oxide particles and zeolite particles is known.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although various adsorbents for adsorbing and recovering phosphorus and nitrogen are known, there is a demand for an adsorbent that can more effectively adsorb and recover phosphorus and nitrogen.

[0006] The present invention has been made in view of the above matters, and an object thereof is to provide an adsorbent capable of adsorbing and recovering phosphorus and nitrogen in a solution such as sewage sludge, a method for producing a fertilizer, and a fertilizer.

Means for Solving the Problems

[0007] The adsorbent according to the first aspect of the present invention is containing 40 to 60 parts by mass of carbon, 20 to 30 parts by mass of iron, 10 to 30 parts by mass of zeolite, and 1 to 10 parts by mass of citric acid, adsorbing phosphorus and / or nitrogen in an aqueous solution, characterized by this.

[0008] Furthermore, it preferably contains a photocatalyst and hornblende ore.

[0009] Also, with respect to 100 parts by mass in total of the carbon, the iron, the zeolite, and the citric acid, it preferably contains 0.08 parts by mass or more of the photocatalyst and 0.7 parts by mass or more of the hornblende ore.

[0010] Also, with respect to 100 parts by mass in total of the carbon, the iron, the zeolite, and the citric acid, it preferably contains 0.24 parts by mass or more of the photocatalyst and 2.1 parts by mass or more of the hornblende ore.

[0011] Also, it is preferable that the carbon is one or more selected from charcoal, coal, and biochar.

[0012] Also, it is preferable that the zeolite is natural zeolite.

[0013] Also, it is preferable that the photocatalyst is titanium oxide.

[0014] The method for manufacturing a fertilizer according to the second aspect of the present invention is as follows. An adsorbent according to the first aspect of the present invention is interposed in a solution containing phosphorus and / or nitrogen. The adsorbent having adsorbed phosphorus and / or nitrogen is separated from the solution. This is the gist of the present invention.

[0015] The fertilizer according to the third aspect of the present invention is as follows. An adsorbent according to the first aspect of the present invention, and phosphorus and / or nitrogen adsorbed on the adsorbent. This is the gist of the present invention.

Advantages of the Invention

[0016] According to the present invention, it is possible to provide an adsorbent capable of adsorbing and recovering phosphorus and nitrogen in a solution such as sewage sludge, a method for manufacturing a fertilizer, and a fertilizer.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0018] The adsorbent according to the present embodiment adsorbs phosphorus and nitrogen in an aqueous solution and contains carbon, zeolite, iron, and citric acid.

[0019] As the carbon, charcoal, coal, biochar, etc. can be used. When the total of the carbon, zeolite, iron and citric acid is 100 parts by mass, the carbon content is preferably 40 to 60 parts by mass, more preferably 50 to 60 parts by mass.

[0020] As the zeolite, either artificial zeolite or natural zeolite may be used, but natural zeolite is preferred. Further, mordenite is preferably used as the natural zeolite. Natural zeolite is an ore composed of crystalline aluminosilicate and contains various minerals such as calcium, magnesium, sodium, potassium, etc., and has the property of being able to maintain its function for a long time without being affected by the surrounding environment. When the total of the carbon, zeolite, iron and citric acid is 100 parts by mass, the zeolite content is preferably 10 to 30 parts by mass, more preferably 15 to 20 parts by mass.

[0021] The iron is not particularly limited, such as iron scraps, etc. When the total of the carbon, zeolite, iron and citric acid is 100 parts by mass, the iron content is preferably 20 to 30 parts by mass, more preferably 23 to 27 parts by mass.

[0022] Citric acid functions to combine with iron to form divalent iron. When the total of the carbon, zeolite, iron and citric acid is 100 parts by mass, the citric acid content is preferably 1 to 10 parts by mass, more preferably 3 to 7 parts by mass.

[0023] The adsorbent preferably further contains a photocatalyst and hornblende ore. Compared with the case where the hornblende ore and the photocatalyst are not contained, the adsorbent containing the photocatalyst and the hornblende ore has a significantly increased adsorption amount of phosphorus and nitrogen. Although the principle is not clear, the adsorption of phosphorus and nitrogen is promoted by containing the hornblende ore and the photocatalyst.

[0024] As a photocatalyst, titanium dioxide can be mentioned. Titanium dioxide is widely known as a photocatalyst and is a substance with a strong photocatalytic function among photocatalysts. The content of the photocatalyst is preferably 0.08 parts by mass or more, and preferably 0.24 parts by mass or more with respect to 100 parts by mass of the total amount of carbon, zeolite, iron and citric acid.

[0025] Hornfels ore is formed by the contact deformation of protoliths such as sandstone, mudstone, and shale. Hornfels ore mainly consists of silicon oxide and aluminum oxide, contains other chemical components such as sodium, magnesium, iron oxide, etc., and may further contain elements such as rubidium, titanium, and strontium. The content of hornfels ore is preferably 0.7 parts by mass or more, and more preferably 2.1 parts by mass or more with respect to 100 parts by mass of the total amount of carbon, zeolite, iron and citric acid.

[0026] The adsorbent can be produced by mixing the above-mentioned raw material powders, adding water and kneading, and then granulating the kneaded product. Granulation can be carried out using a known granulating device. There is no limitation on the size and shape of the adsorbent, but from the viewpoint of increasing the specific surface area of the adsorbent to increase the adsorption amount of phosphorus and nitrogen, and from the viewpoint of ease of handling of the adsorbent, for example, it is advisable to make it into granules with a diameter of 3 to 10 mm.

[0027] The adsorbent can adsorb and recover phosphorus and nitrogen in the solution by being placed in a solution containing phosphorus and nitrogen such as sewage sludge, wastewater, and waste water. The adsorbent can be placed in the solution by desired means such as putting the adsorbent in a net bag and hanging it. After adsorption, the adsorbent is separated from the solution and, if necessary, dried and pulverized to obtain a fertilizer containing phosphorus and nitrogen. Since the adsorbent does not contain harmful components, the adsorbent adsorbed and recovered with phosphorus and nitrogen can be effectively used as a fertilizer.

Example

[0028] (Manufacture of adsorbent) With the compositions shown in Table 1 and Table 2, each powdery raw material was mixed, and water was added and kneaded. Then, the kneaded material was granulated into granules with a diameter of about 5 mm and naturally dried to produce Adsorbents 1 to 9 and 11 to 25, respectively.

[0029]

Table 1

[0030]

Table 2

[0031] In Table 2, Aospowder (manufactured by Audemels Co., Ltd.) is a mixed powder in which hornfels ore: zeolite: titanium oxide is mixed at a mass ratio of 70:22:8. The blending ratios of hornfels ore, zeolite, and titanium oxide in Adsorbents 11 to 25 are shown in Table 3.

[0032]

Table 3

[0033] (Experiment 1-1) Adsorption experiment of phosphorus by Adsorbents 1 to 9 An aqueous phosphoric acid solution (phosphorus concentration: 5 mg / L) was prepared by dissolving phosphoric acid (H3PO4) in water. An aqueous phosphoric acid solution (1 L) was placed in a container, and a net containing each of Adsorbents 1 to 9 was suspended so that it was located at a depth of 1 / 3 from the surface of the aqueous phosphoric acid solution. After adding Adsorbents 1 to 9 to the aqueous phosphoric acid solution, the total phosphorus concentration in the aqueous phosphoric acid solution was measured over time. The measurement of the total phosphorus concentration was carried out using Pack Test Total Phosphorus (Pack Test is a registered trademark) (WAK-PO4, Kyoritsu Chemical-Check Laboratory Co., Ltd.). The results are shown in Table 4.

[0034]

Table 4

[0035] In any of the adsorbents, the phosphorus concentration has been decreasing over time, indicating that the adsorption of phosphorus is progressing. Also, in any of the coals, the adsorption amounts at 50 parts by mass and 60 parts by mass were higher than that at 40 parts by mass.

[0036] (Experiment 1-2) Adsorption experiment of phosphorus by adsorbents 11 to 25 Using adsorbents 11 to 25, an adsorption experiment of phosphorus was conducted in the same manner as above. The results of adsorbents 11 to 15, adsorbents 16 to 20, and adsorbents 21 to 25 are shown in Tables 5 to 7, respectively. Also, the results of adsorbents 2 and 11 to 15, adsorbents 5 and 16 to 20, and adsorbents 8 and 21 to 25 are shown in Figures 1 to 3, respectively.

[0037]

Table 5

[0038]

Table 6

[0039]

Table 7

[0040] When hornfels ore and titanium oxide are contained, the adsorption amount of phosphorus is clearly higher. In particular, when hornfels ore is contained at 2.1 parts by mass or more and titanium oxide is contained at 0.24 parts by mass or more, it can be seen that the adsorption amount is greatly improved. In addition, when hornfels ore is contained at 3.5 parts by mass or more and titanium oxide is contained at 0.4 parts by mass or more, a plateau in the adsorption effect is observed.

[0041] (Experiment 2-1) Adsorption experiment of nitrogen by adsorbents 1 to 9 An aqueous nitrogen solution (nitrogen concentration: 75 mg / L) in which ammonium nitrate was dissolved in water was prepared. The aqueous nitrogen solution (1 L) was placed in a container, and adsorbents 1 to 9 were each added. The addition of the adsorbent was carried out in the same manner as in Experiment 1-1 described above.

[0042] After adding the adsorbent to the aqueous nitrogen solution, the total nitrogen concentration in the aqueous nitrogen solution was measured over time. The measurement of the total nitrogen concentration was carried out using Pack Test Total Nitrogen (Inorganic) ( "Pack Test" is a registered trademark) (WAK-TN-i-3, Kyoritsu Chemical-Check Laboratory Co., Ltd.). The results are shown in Table 8.

[0043]

Table 8

[0044] In any of the adsorbents, the nitrogen concentration decreased over time, indicating that the adsorption of phosphorus was progressing. Also, in any of the coals, the adsorption amounts at 50 parts by mass and 60 parts by mass were higher than those at 40 parts by mass.

[0045] (Experiment 2-2) Nitrogen adsorption experiment using adsorbents 11 to 25 Using adsorbents 11 to 25, a nitrogen adsorption experiment was conducted in the same manner as in Experiment 2-1 described above. The results of adsorbents 11 to 15, adsorbents 16 to 20, and adsorbents 21 to 25 are shown in Tables 9 to 11, respectively. Also, the results of adsorbents 2 and 11 to 15, adsorbents 5 and 16 to 20, and adsorbents 8 and 21 to 25 are shown in Figures 4 to 6, respectively.

[0046]

Table 9

[0047]

Table 10

[0048]

Table 11

[0049] When hornfels ore and titanium oxide are contained, the nitrogen adsorption amount is clearly increased. In particular, when the hornfels ore is contained in an amount of 2.1 parts by mass or more and the titanium oxide is contained in an amount of 0.24 parts by mass or more, it can be seen that the adsorption amount is greatly improved. When the hornfels ore is contained in an amount of 3.5 parts by mass or more and the titanium oxide is contained in an amount of 0.4 parts by mass or more, a plateau of the adsorption effect is observed.

Claims

1. It contains 40 to 60 parts by mass of carbon, 20 to 30 parts by mass of iron, 10 to 30 parts by mass of zeolite, and 1 to 10 parts by mass of citric acid, and adsorbs phosphorus and / or nitrogen in an aqueous solution. An adsorbent characterized by this.

2. Furthermore, it contains a photocatalyst and hornblende ore. The adsorbent according to Claim 1, characterized by this.

3. Based on 100 parts by mass in total of the carbon, the iron, the zeolite, and the citric acid, it contains 0.08 parts by mass or more of the photocatalyst and 0.7 parts by mass or more of the hornblende ore. The adsorbent according to Claim 2, characterized by this.

4. Based on 100 parts by mass in total of the carbon, the iron, the zeolite, and the citric acid, it contains 0.24 parts by mass or more of the photocatalyst and 2.1 parts by mass or more of the hornblende ore. The adsorbent according to Claim 2, characterized by this.

5. The carbon is one or more selected from charcoal, coal, and biochar. The adsorbent according to Claim 1, characterized by this.

6. The zeolite is natural zeolite. The adsorbent according to Claim 1, characterized by this.

7. The photocatalyst is titanium oxide. The adsorbent according to Claim 2, characterized by this.

8. Interpose the adsorbent according to any one of Claims 1 to 7 in a solution containing phosphorus and / or nitrogen, and separate the adsorbent having adsorbed phosphorus and / or nitrogen from the solution. A method for producing a fertilizer, characterized by this.

9. It includes the adsorbent according to any one of Claims 1 to 7 and phosphorus and / or nitrogen adsorbed on the adsorbent. A fertilizer characterized by this.

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