A porous material, a method for its preparation and its use

Abstract

The application provides a kind of porous material, its preparation method and its application, the raw material of the porous material includes the following weight parts of components: engineering spoil: 25-40 parts;Pyrite powder: 25-40 parts;Silica fume: 10-15 parts;Boric acid and / or its salt: 10-15 parts;And carbonate and / or bicarbonate: 5-10 parts.In the application, engineering spoil, pyrite, silica fume derived from industrial or construction waste are used for sintering, which increases the way of waste resource utilization, reduces the damage of the above waste to the environment, and protects the environment;Boric acid substances reduce the sintering temperature of traditional porous materials, save energy and reduce consumption;Carbonate or bicarbonate is used for foaming to increase the specific surface area of the material and enhance the adsorption property;The raw material components are scientifically compounded and reasonably proportioned, the phosphorus removal rate can reach more than 80% when rainwater is treated by the application, and the price is low due to the wide sources of each component, thereby effectively reducing the preparation cost.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection, specifically including a porous material, its preparation method, and its application. Background Technology

[0002] With the development of the national economy and the increase in urbanization, problems such as urban flooding, the heat island effect, and runoff pollution have become increasingly prominent. As early as 2014, my country issued the "Technical Guidelines for Sponge City Construction," vigorously developing sponge cities in an effort to solve these persistent problems. The construction of sponge cities is based on the concept of "infiltration, retention, storage, and purification," organically combining artificial facilities with the natural ecosystem to gradually achieve automatic rainwater storage, infiltration, and purification. Ecological materials play a crucial role in this process. Ecological materials are porous materials that simultaneously possess water storage, permeability, and purification functions. Combining the needs of sponge city construction, ecological materials, while meeting the requirements of "permeability" to alleviate flooding, should also have a certain "storage" and "purification" capacity. They can store water during rainfall and release it when needed, mitigating the heat island effect, and effectively remove pollutants such as phosphorus from rainwater during the permeation process, achieving water purification and alleviating pressure on urban drinking water.

[0003] However, existing eco-materials often struggle to achieve a balance between good phosphorus removal efficiency, low cost, and environmentally friendly production. For example, Chinese patent application number 201410644565.3 reports a method for preparing porous adsorbent materials from pyrite slag. The preparation process is relatively complex. First, the material is ball-milled, then magnetically separated to select high-iron, low-sulfur pyrite concentrate, and then dried and roasted at 800-1000℃ to obtain porous materials. The preparation process of this patent is complex, which is not conducive to the large-scale application of sponge cities. For example, Chinese patent CN113735246 A discloses a phosphorus-removing foaming lightweight filler, whose main raw materials are sulfur powder, pyrite powder, limestone, foaming agent, and foam stabilizer. The sulfur powder is a highly polluting raw material. Similarly, Chinese patent CN110078221 A discloses a phosphorus-removing lightweight material and its preparation and application method. It obtains a molten mixture by fully melting and dispersing sulfur and iron-based components, wherein the iron-based components are a mixture of pyrite and calcium magnesium carbonate. The molten mixture is then foamed to form a phosphorus-removing lightweight material, which also contains sulfur raw materials. Chinese patent CN110002806B requires the addition of both foaming agent and foam stabilizer, making its composition complex and increasing the preparation cost. Summary of the Invention

[0004] The main objective of this invention is to provide a porous material, its preparation method, and its application, aiming to provide a porous material with good phosphorus removal effect, simple preparation, and strong environmental friendliness.

[0005] To achieve the above objectives, the present invention provides a porous material, wherein the raw materials of the porous material comprise the following components in parts by weight:

[0006] Construction waste: 25 to 40 portions;

[0007] Pyrite powder: 25-40 parts;

[0008] Silica fume: 10 to 15 parts;

[0009] Boric acid and / or its salts: 10 to 15 parts; and,

[0010] Carbonates and / or bicarbonates: 5 to 10 parts.

[0011] Optionally, the raw material of the porous material comprises the following components in parts by weight:

[0012] The amount of excavated soil from the project: 31 portions;

[0013] The pyrite powder: 31 parts;

[0014] The boric acid and / or its salt: 15 parts;

[0015] 15 parts of the silica fume; and,

[0016] The carbonate and / or bicarbonate: 8 parts.

[0017] Optionally, the excavated soil contains at least 80% by mass of active substances, including silica, alumina, and iron oxide; and / or,

[0018] The pyrite powder contains not less than 50% by mass of ferrous sulfide; and / or,

[0019] The silica fume contains not less than 80% silica by mass.

[0020] Optionally, the boric acid includes orthoboric acid and / or tetraboric acid; and / or,

[0021] The salt corresponding to the boric acid is hydrated tetraborate; and / or,

[0022] The carbonate includes sodium carbonate and / or potassium carbonate; and / or,

[0023] The bicarbonate includes sodium bicarbonate and / or potassium bicarbonate.

[0024] Optionally, the excavated soil contains clay particles, and the specific surface area of ​​the clay particles is 10 to 1000 m². 2 / g; and / or,

[0025] The pyrite powder has a particle size of 300–500 μm; and / or,

[0026] The silica fume has a particle size of 4000 mesh to 8000 mesh.

[0027] Furthermore, the present invention provides a method for preparing the above-mentioned porous material, the method comprising:

[0028] The engineering waste soil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume are added to a solvent and mixed, dried to form a shape, and then sintered to obtain a porous material.

[0029] Optionally, the solvent is ethanol.

[0030] Optionally, the sintering includes a first stage sintering and a second stage sintering, wherein the temperature of the first stage sintering is 400-440°C and the sintering time is 20-30 min, the temperature of the second stage sintering is 880-900°C and the sintering time is 20-30 min.

[0031] Optionally, before the step of mixing the engineering waste soil, the pyrite powder, the boric acid and / or its salts, the carbonates and / or the bicarbonates, and the silica fume in a solvent, drying to a final shape, and then sintering to obtain a porous material, the method further includes:

[0032] The pyrite is ground into pyrite powder with a particle size of 300 μm to 500 μm.

[0033] Furthermore, the present invention also provides a method for reducing the phosphorus content in water, the method comprising the following steps:

[0034] Provide water to be treated;

[0035] The porous material described above is added to the water to be treated to initiate a reaction.

[0036] In this invention, sintering is carried out using engineering waste soil, pyrite, and silica fume derived from industrial or construction waste, which increases the ways to utilize waste resources, reduces the environmental damage caused by the aforementioned wastes, and protects the environment. Boric acid substances lower the sintering temperature of traditional porous materials, saving energy and reducing consumption. Foaming with carbonates or bicarbonates increases the specific surface area of ​​the material and enhances its adsorption capacity. Its raw material composition is scientifically compounded and rationally proportioned. When used to treat rainwater for dephosphorization, the dephosphorization rate can reach more than 80%. At the same time, the various components are widely available and therefore inexpensive, effectively reducing the preparation cost. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 The preparation process of a porous material according to an embodiment of the present invention is described below.

[0039] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0041] It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available products. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0042] In view of the technical shortcomings of existing dephosphorization materials, which cannot simultaneously achieve dephosphorization, environmentally friendly material sources, and low preparation costs, this invention provides a porous material, wherein the raw materials of the porous material include the following components in parts by weight:

[0043] Construction waste: 25 to 40 portions;

[0044] Pyrite powder: 25-40 parts;

[0045] Silica fume: 10 to 15 parts;

[0046] Boric acid and / or its salts: 10 to 15 parts; and,

[0047] Carbonates and / or bicarbonates: 5 to 10 parts.

[0048] In this invention, sintering is carried out using engineering waste soil, pyrite, and silica fume derived from industrial or construction waste, which increases the ways to utilize waste resources, reduces the environmental damage caused by the aforementioned wastes, and protects the environment. Boric acid substances lower the sintering temperature of traditional porous materials, saving energy and reducing consumption. Foaming with carbonates or bicarbonates increases the specific surface area of ​​the material and enhances its adsorption capacity. Its raw material composition is scientifically compounded and rationally proportioned. When used to treat rainwater for dephosphorization, the dephosphorization rate can reach more than 80%. At the same time, the various components are widely available and therefore inexpensive, effectively reducing the preparation cost.

[0049] The term "engineering waste soil" as used in this invention refers to raw soil located 1m below the surface, which is essentially a composite of clay and gravel, rich in fine clay particles with a large specific surface area of ​​10-1000 m² / g. Existing technologies generally consider pyrite to have good removal effects on total nitrogen and total phosphorus in wastewater. However, raw pyrite has a high specific gravity, small specific surface area, and low utilization rate of its effective components. Although pyrite powder can increase the specific surface area, it is prone to detachment and clogging when used as a packing material in biological filters.

[0050] The excavated soil from the construction project has strong adsorption properties and can adsorb phosphorus from the water; secondly, FeS2 in pyrite will produce Fe during the reaction process. 3+ Or Fe(OH)3, which can react with PO3 -4 The phosphorus in the water is removed by precipitation or adsorption by Fe(OH)3.

[0051] The inventors' research team discovered that combining pyrite powder with engineering waste soil not only combines the advantages of porous materials from engineering waste soil and pyrite in wastewater treatment, but also, during the phosphorus removal process, pyrite promotes the phosphorus adsorption performance of porous materials from engineering waste soil. In turn, the phosphorus adsorption performance of porous materials from engineering waste soil allows pyrite to fully contact these substances, further increasing the utilization rate of pyrite powder. The two promote each other and have a synergistic effect, resulting in a better phosphorus removal effect than either porous materials from engineering waste soil or pyrite powder alone.

[0052] Furthermore, the silica fume, boric acid substances, and pore-forming carbonates or bicarbonates in this invention promote and strengthen the molding of both materials, allowing the pyrite powder to adhere firmly to the substrate of the engineering waste soil, increasing the specific surface area of ​​the entire material, and giving the material lightweight and wear-resistant properties.

[0053] In some embodiments, the raw material of the porous material comprises the following components in parts by weight:

[0054] Construction waste: 31 portions;

[0055] Pyrite powder: 31 parts;

[0056] Boric acid and / or its salts: 15 parts;

[0057] 15 parts silica fume; and,

[0058] Carbonates and / or bicarbonates: 8 parts.

[0059] The above ratio will further improve the material's phosphorus removal rate in water.

[0060] In some embodiments, the engineering waste soil contains at least 80% by mass of active substances, including silica, alumina, and iron oxide.

[0061] The aforementioned active substances can undergo chemical solid-phase reactions during sintering to generate silicates, aluminates, and ferrates of a certain strength, which can serve as a carrier to support and load pyrite powder.

[0062] In some embodiments, the pyrite powder contains at least 50% ferrous sulfide by mass. When the ferrous sulfide content is at least 50%, the phosphorus removal efficiency can be further improved.

[0063] In some embodiments, the silica fume contains not less than 80% by weight of silica.

[0064] Insufficient silicon content in construction waste leads to a lack of silicon-oxygen tetrahedra in the fired products, resulting in a certain degree of decreased strength. Increasing the silica content can replenish the silicon in the construction waste and improve the stability of the products.

[0065] In some embodiments, the boric acid includes orthoboric acid and / or tetraboric acid; using the above-mentioned boric acid or borate can further reduce the sintering temperature. In some embodiments, the salt corresponding to the boric acid is hydrated tetraborate, more specifically, when it is sodium tetraborate decahydrate, the sintering temperature can be reduced to 800°C to 900°C.

[0066] It should be noted that, in this invention, the specific materials used for pore formation are not limited, provided that the pores are formed based on the decomposition of carbonate and bicarbonate ions. Specifically, the carbonates include sodium carbonate and / or potassium carbonate; the bicarbonates include sodium bicarbonate and / or potassium bicarbonate. More preferably, sodium bicarbonate is used for pore formation, resulting in better phosphorus removal efficiency.

[0067] In some embodiments, the particle size of the pyrite powder is 300-500 μm. If the particle size of pyrite is too large, its specific surface area will be too small, which will lead to uneven distribution of pyrite in the sintering material and affect the adsorption effect of the product on total phosphorus. Pyrite itself is a hard particle, and an excessively large particle size will lead to energy waste and material wear during the grinding process, which is not economically efficient.

[0068] In some embodiments, the particle size of the silica fume is 4000 mesh to 8000 mesh. Silica fume is formed when a large amount of highly volatile SiO2 and Si gases are generated in a submerged arc furnace during the smelting of ferrosilicon and industrial silicon (metallic silicon). After the gases are emitted, they rapidly oxidize, condense, and precipitate with air. It is a byproduct of large-scale industrial smelting, and its particle size range is relatively stable, around 4000-8000 mesh.

[0069] Furthermore, the present invention provides a method for preparing the above-mentioned porous material, the method comprising:

[0070] The engineering waste soil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume are added to a solvent and mixed, dried to form a shape, and then sintered to obtain a porous material.

[0071] It should be noted that, provided that the raw materials are dispersible, the solvent of the present invention is not limited. Specifically, in some embodiments, the solvent is ethanol. Using ethanol as a solvent can accelerate evaporation and molding.

[0072] In some embodiments, the sintering includes a first stage sintering and a second stage sintering in sequence, wherein the temperature of the first stage sintering is 400-440°C and the time of the first stage sintering is 20-30 min, the temperature of the second stage sintering is 880-900°C and the time of the second stage sintering is 20-30 min.

[0073] The first stage of sintering is the preheating stage. The preheating temperature has a significant impact on the strength and bulk density of the sintered product. During this stage, the foaming agent fully foams, causing the sintered material to expand and creating a porous structure inside the product, increasing the specific surface area. The second stage of sintering is the sintering stage, where the silica, alumina, iron oxide, calcium carbonate, and other components in the sintered material fully react, forming a stable three-dimensional network structure at the microscopic level, producing sufficient strength to support the pyrite.

[0074] It should be noted that in this invention, the pyrite powder of a specific particle size can be purchased or ground by oneself. In some embodiments, before the step of mixing the engineering waste soil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume with a solvent, drying to form, and then sintering to obtain a porous material, the method further includes: grinding the pyrite into pyrite powder with a particle size of 300-500 μm.

[0075] Furthermore, the present invention also provides a method for reducing the phosphorus content in water, the method comprising the following steps:

[0076] Step A10: Provide the water to be treated;

[0077] Step A20: Add the above-mentioned porous material to the water to be treated and react.

[0078] When using the above-mentioned porous materials to remove phosphorus from water, the phosphorus content can be effectively reduced, with a removal rate of over 80%.

[0079] It should be noted that the source of water is not limited. In this invention, the phosphorus content in the water is 2.33 mg / L (similar to that of initial rainwater). When 0.04 g of the porous material is used per 1 ml and reacted at room temperature for 25°C, the absorption rate reaches more than 80%, proving that the porous material of this invention has a good removal effect on phosphorus in rainwater.

[0080] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0081] Examples 1-4

[0082] Examples 1 to 4 each provide a porous material, the composition of which is shown in Table 1.

[0083] Table 1. Composition of raw materials for porous materials and corresponding weight parts

[0084]

[0085] The particle sizes of pyrite powder and silica fume in Examples 1-4 are shown in Table 2. The specific surface area of ​​the engineering waste soil in Examples 1-4 is 56 m². 2 / g, the active components and contents of the engineering waste soil in Examples 1 to 4 are shown in Table 3. The silica fume contains 92% silica by mass and the pyrite powder contains 65% ferrous sulfide by mass.

[0086] Table 2 shows the particle size of pyrite powder and silica fume in Examples 1-4.

[0087] Pyrite powder particle size (μm) Silica fume particle size (mesh) Example 1 300-400 6000 Example 2 300-400 6000 Example 3 300-400 6000 Example 4 300-400 6000

[0088] Table 3. Components and contents of active substances in engineering waste soil from Examples 1-4

[0089] Quality percentage (%) <![CDATA[SiO2]]> 49.53 <![CDATA[Al2O3]]> 31.21 <![CDATA[Fe2O3]]> 4.62 MgO 0.429 <![CDATA[Na2O]]> 0.10 <![CDATA[K2O]]> 2.26 CaO 0.53

[0090] Examples 1-4 also provide methods for preparing the above-mentioned porous materials, including the following steps:

[0091] Pyrite is ground to obtain pyrite powder;

[0092] Weigh out the engineering waste soil, pyrite powder, sodium tetraborate decahydrate, silica fume, and sodium bicarbonate according to the weight proportions in the table above. Mix the raw materials evenly, add an appropriate amount of anhydrous ethanol, stir and shape to obtain sintered raw material. Place the sintered raw material into a muffle furnace and pass it through the first stage sintering and the second stage sintering in sequence. After cooling the sintered clinker to room temperature, porous material can be obtained. The conditions for the first stage sintering and the second stage sintering in Examples 1 to 4 are shown in Table 4.

[0093] Table 4 Conditions for the first and second stage sintering in Examples 1-4

[0094]

[0095] Example 5

[0096] This embodiment provides a porous material with a composition that is largely the same as that in Example 1, except that sodium tetraborate decahydrate is replaced with orthoboric acid.

[0097] Pyrite is ground to obtain pyrite powder;

[0098] Weigh out the engineering waste soil, pyrite powder, orthoboric acid, silica fume, and sodium bicarbonate according to the weight proportions. Mix the raw materials evenly, add an appropriate amount of anhydrous ethanol, stir and shape to obtain sintered raw material. Put the sintered raw material into a muffle furnace and pass it through the first stage sintering and the second stage sintering in sequence. After cooling the sintered clinker to room temperature, the porous material can be obtained. The conditions for the first stage sintering and the second stage sintering in Example 5 are shown in Table 5.

[0099] Table 5. Conditions for the first and second stage sintering in Example 5

[0100]

[0101] Example 6

[0102] This embodiment provides a porous material whose composition and preparation method are largely the same as those in Example 1, except that the specific surface area of ​​the engineering waste soil is 56 m². 2 / g, the active components and contents of the engineering waste soil in Example 6 are shown in Table 6. The silica fume contains 80% silica by mass, and the pyrite powder contains 70% ferrous sulfide by mass.

[0103] Table 6. Components and contents of active substances in engineering waste soil in Example 6

[0104]

[0105] Example 7

[0106] This embodiment provides a porous material whose composition and preparation method are largely the same as those in Example 2, except that the specific surface area of ​​the engineering waste soil is 56 m².2 / g, the active components and contents of the engineering waste soil in Example 7 are shown in Table 7. The silica fume contains 95% silica by mass, and the pyrite powder contains 50% ferrous sulfide by mass.

[0107] Table 7. Components and content of active substances in engineering waste soil in Example 7

[0108]

[0109] Application Examples 1-7

[0110] The porous materials from Examples 1 to 7 were used for water phosphorus removal treatment. The porous ecological materials were weighed into 1L conical flasks, and 500mL of simulated initial rainwater solution with an initial phosphorus concentration of 2.33mg / L was added to the conical flasks. The conical flasks were placed in a constant temperature shaking incubator at 25℃ and a rotation speed of 160r / min. After reacting for 24h, the phosphorus concentration in the water was measured, and the removal rate was calculated. The content of porous materials in the simulated initial rainwater solution added in the application examples is shown in Table 8.

[0111] Table 8 shows the content of porous materials added in application examples 1-7.

[0112] Application Examples Amount of porous material added (g) Application Example 1 20 Application Example 2 20 Application Example 3 20 Application Example 4 20 Application Example 5 25 Application Example 6 30 Application Example 7 25

[0113] Comparative Example 1

[0114] Weigh 20g of commercially available glass pumice into a 1L conical flask. Add 500mL of simulated initial rainwater solution with an initial phosphorus concentration of 2.33mg / L to the conical flask. Place the conical flask in a constant temperature shaking incubator and shake at 25℃ and 160r / min. After reacting for 24h, measure the phosphorus concentration in the water and calculate the removal rate.

[0115] Comparative Example 2

[0116] Weigh 20g of pyrite powder into a 1L conical flask, add 500mL of simulated initial rainwater solution with an initial phosphorus concentration of 2.33mg / L into the conical flask, place the conical flask in a constant temperature shaking incubator and shake at a temperature of 25℃ and a rotation speed of 160r / min. After reacting for 24h, measure the phosphorus concentration in the water and calculate the removal rate.

[0117] Comparative Example 3

[0118] Weigh 20g of excavated soil into a 1L conical flask. Add 500mL of simulated initial rainwater solution with an initial phosphorus concentration of 2.33mg / L to the conical flask. Place the conical flask in a constant temperature shaking incubator and shake at 25℃ and 160r / min. After reacting for 24h, measure the phosphorus concentration in the water and calculate the removal rate.

[0119] The phosphorus concentration and removal rate after treatment in Application Examples 1-7 and Comparative Examples 1-3 are shown in Table 9.

[0120] Table 9. Detection results after P treatment.

[0121] Phosphorus concentration (mg / L) Removal rate (%) Application Example 1 0.16 93.13 Application Example 2 0.37 84.12 Application Example 3 0.43 81.54 Application Example 4 0.24 89.70 Application Example 5 0.41 82.40 Application Example 6 0.38 83.69 Application Example 7 0.39 83.26 Comparative Example 1 0.7 66.95 Comparative Example 2 0.57 75.65 Comparative Example 3 0.68 70.82

[0122] Compared to Comparative Examples 1-3, the composite raw materials of engineering waste soil, pyrite powder, and silica fume used in Application Examples 1-7 produce porous materials with better performance than those made from single glass pumice, engineering waste soil, and pyrite powder. The phosphorus removal rate reaches over 80%. Moreover, when the weight of engineering waste soil is 31 parts, pyrite powder is 31 parts, boric acid and / or its salts is 15 parts, silica fume is 15 parts, and the carbonates and / or bicarbonates are 8 parts, the phosphorus removal rate reaches over 90%.

[0123] Furthermore, when boric acid and / or its salts are specifically sodium tetraborate decahydrate, the sintering temperature can be effectively reduced, thereby reducing energy consumption during preparation.

[0124] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A porous material, characterized in that, The raw material of the porous material comprises the following components in parts by weight: Engineered spoil: 25-40 parts; Pyrite powder: 25-40 parts; Silica fume: 10-15 parts; Boric acid and / or its salt: 10-15 parts; Carbonate and / or bicarbonate: 5-10 parts; The preparation method of the porous material comprises the following steps: The engineered spoil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume are mixed in a solvent, dried, and then sintered after shaping to obtain the porous material; The sintering comprises a first-stage sintering and a second-stage sintering, wherein the temperature of the first-stage sintering is 400-440℃, the time of the first-stage sintering is 20-30 min, the temperature of the second-stage sintering is 880-900℃, and the time of the second-stage sintering is 20-30 min. The raw material of the porous material comprises the following components in parts by weight:

2. The porous material of claim 1, wherein, The engineered spoil: 31 parts; The pyrite powder: 31 parts; The boric acid and / or its salt: 15 parts; The silica fume: 15 parts; and The carbonate and / or bicarbonate: 8 parts. The engineered spoil contains not less than 80% of active substances in mass percentage, and the active substances comprise silicon dioxide, aluminum oxide, and iron oxide; and / or, 3. The porous material of claim 1, wherein, The pyrite powder contains not less than 50% of ferrous sulfide in mass percentage; and / or, The silica fume contains not less than 80% of silicon dioxide in mass percentage. The boric acid comprises orthoboric acid and / or tetraboric acid; and / or, 4. The porous material of claim 1, wherein, The salt corresponding to the boric acid is hydrated tetraborate; and / or, The carbonate comprises sodium carbonate and / or potassium carbonate; and / or, The bicarbonate comprises sodium bicarbonate and / or potassium bicarbonate. The particle size of the pyrite powder is 300-500 μm; and / or, 5. The porous material of claim 1, wherein, The engineered spoil contains clay particles, and the specific surface area of the clay particles is 10-1000 m 2 / g; and / or, The particle size of the silica fume is 4000-8000 mesh. In the step of mixing the engineered spoil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume in a solvent, drying, and then sintering after shaping to obtain the porous material, the solvent is ethanol.

6. The porous material of claim 1, wherein, Before the step of mixing the engineered spoil, the pyrite powder, the boric acid and / or its salt, the carbonate and / or the bicarbonate, and the silica fume in a solvent, drying, and then sintering after shaping to obtain the porous material, the step further comprises:

7. The porous material of claim 1, wherein, Grinding the pyrite into the pyrite powder with a particle size of 300-500 μm. The method for reducing the content of phosphorus in water comprises the following steps:

8. A method of reducing the phosphorus content of water, characterized in that, Providing water to be treated; Adding the porous material according to any one of claims 1-7 into the water to be treated for reaction. ​

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