A porous composite material, its preparation method and use

Abstract

The present application relates to the field of environmental functional materials, and more particularly to a porous composite material, a preparation method and application thereof.The porous composite material comprises the following raw materials in mass fraction: a compound of fly ash and coal gangue 45-60 parts, cement 15-25 parts, humus 5-15 parts, aluminum powder 0.1-0.5 parts, starch 3-8 parts, ammonium sulfate 1-3 parts, and quartz sand 2-8 parts; wherein the humus has an organic matter content of 35wt% or more and a pH of 6-7.5.The porous composite material provided by the present application can realize a complete closed loop from an environmental management end point to a hydrogen energy material starting point and then to an agricultural recycling node.

Description

Technical Field

[0001] This invention relates to the field of environmental functional materials, and in particular to a porous composite material, its preparation method, and its application. Background Technology

[0002] Copper is a typical heavy metal pollutant in urban stormwater runoff, mainly originating from industrial emissions, metal corrosion, automotive brake pad wear, and pesticide use. It is significantly toxic to aquatic ecosystems. Traditional phytoretention systems have limited capacity to remove dissolved copper and are functionally singular, failing to meet the needs of sustainable development.

[0003] On the other hand, the stockpiling of industrial solid waste (fly ash, coal gangue) and construction waste causes serious environmental pressure. Fly ash and coal gangue are rich in strategic elements such as aluminum, magnesium, and silicon, and have potential resource utilization value. In existing technologies, such as patent CN115746382B, a method for preparing porous silica-alumina oxide / chitosan composite materials using silica fume and secondary aluminum ash via a sol-gel method is disclosed, mainly for use in thermal insulation or general adsorption fields. However, existing technologies still have the following bottlenecks: Fly ash / coal gangue-based materials have insufficient mechanical properties, are prone to embrittlement and breakage in soil environments, and are difficult to recycle completely; the materials have limited functions and fail to effectively link pollution control with the resource utilization value of elements after the materials have been used; there is a lack of systematic design for the resource utilization path of saturated materials throughout their entire life cycle, especially the failure to organically combine environmental governance end-stages with hydrogen energy material preparation and agricultural recycling.

[0004] Therefore, there is an urgent need to develop a multifunctional composite material that integrates structural load-bearing, pollution control, hydrogen energy material preparation, and cascade recycling, so as to achieve deep coupling of industrial solid waste disposal, rainwater purification, hydrogen storage material preparation, and agricultural recycling. Summary of the Invention

[0005] This invention provides a porous composite material, its preparation method, and its application, to achieve a complete closed loop from the endpoint of environmental governance to the starting point of hydrogen energy materials and then to the node of agricultural cycle.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a porous composite material comprising the following parts by weight of raw materials: A composite of fly ash and coal gangue, 45-60 parts. 15-25 parts cement 5-15 parts of humus 0.1~0.5 parts aluminum powder, 3-8 parts starch 1-3 parts ammonium sulfate 2-8 parts of quartz sand; The composite material of fly ash and coal gangue is a material obtained by soaking fly ash and coal gangue in an alkaline solution. The humus contains ≥35wt% organic matter and has a pH of 6~7.5.

[0007] In some specific embodiments, the preparation process of the fly ash and coal gangue composite is as follows: Figure 1 As shown, it includes the following steps: Fly ash and crushed coal gangue were mixed and then soaked in sodium hydroxide solution for modification. After soaking, the mixture was washed and dried.

[0008] In some specific embodiments, the mass ratio of the fly ash to the coal gangue is (60~90):(10~40).

[0009] In some specific embodiments, the ratio of the total mass of the fly ash and the coal gangue to the amount of sodium hydroxide solution is 1g:(3~8)mL.

[0010] In some specific embodiments, the concentration of the sodium hydroxide solution is 0.5~2 mol / L.

[0011] In some specific embodiments, the soaking temperature is 10~30℃, and the soaking time is 7~14 days.

[0012] In some specific embodiments, the cement includes ordinary Portland cement.

[0013] In some specific embodiments, the humus is obtained from fallen leaves through composting.

[0014] A second aspect of the present invention also provides a method for preparing the above-mentioned porous composite material, comprising the following steps: A mixture of fly ash and coal gangue, cement, humus, aluminum powder, starch, ammonium sulfate, and quartz sand is prepared to obtain a mixture. After grinding and sieving the mixture, it is placed in a molding mold, then water is sprayed into the mixture, and it is allowed to stand and foam to obtain a foamed preform. The foamed preform is placed in a drying device and heat-treated with coke oven flue gas to allow the foamed preform to foam a second time and be shaped to obtain a foamed body. The foamed material is cured, and the cured material is immersed in zinc sulfate solution for activation to obtain a porous composite material.

[0015] In some specific embodiments, the sieve opening is 8-10 mesh.

[0016] In some specific embodiments, the sprayed water makes the water content of the mixture 25% to 35%.

[0017] In some specific embodiments, the standing foaming time is 10-30 minutes.

[0018] In some specific embodiments, the temperature of the coke oven flue gas is 200~300℃.

[0019] In this invention, the coke oven flue gas is mainly used as a heat source.

[0020] In some specific embodiments, the heat treatment time is 5 to 10 minutes.

[0021] In some specific embodiments, the curing conditions are: temperature 18~22℃, humidity ≥95%, and time 7~28 days.

[0022] In some specific embodiments, the ratio of the cured material to zinc sulfate solution is 1g:(5~20)mL.

[0023] In some specific embodiments, the concentration of the zinc sulfate solution is 0.5~2 mol / L.

[0024] In some specific embodiments, the soaking activation temperature is 10~30℃, and the soaking activation time is 24~48h.

[0025] A third aspect of the present invention also provides the application of the above-described porous composite material in the removal of copper contaminants from rainwater runoff.

[0026] In some specific embodiments, the application includes: The porous composite material is incorporated into the functional layer of the plant retention system to adsorb copper pollutants in rainwater runoff. In the plant retention system, the functional layer is laid below the planting soil layer and above the drainage layer.

[0027] In some specific embodiments, after the porous composite material becomes saturated with copper contaminants, it is recycled as a resource. The resource recycling method includes: a) The porous composite material saturated with adsorbed copper contaminants was removed, crushed, and powdered. b) Selective leaching and recovery of copper using hydrometallurgical methods; c) Utilizing the pre-activation effect formed by the material during its service in the soil and the through-hole structure constructed by cement hydration products, aluminum, magnesium and silicon elements are extracted from the residue after copper leaching. d) The extracted aluminum and magnesium elements will be used as raw materials for preparing aluminum-based hydrogen production materials and magnesium-based hydrogen storage alloys, respectively. e) The remaining residue after extraction is returned to farmland as a soil conditioner for planting energy crops.

[0028] In some specific embodiments, the resource recycling method specifically includes the following steps: (1) The porous composite material saturated with adsorbed copper pollutants was removed and crushed to obtain powder; (2) The powder was placed in a sulfuric acid solution with pH=2.0 and leached at 50°C for 2 hours to obtain copper leaching solution and copper leaching residue. The leaching solution was electrolyzed to recover metallic copper. (3) The copper leaching residue was mixed with NaOH at a mass ratio of 1:1 and melted at 600℃ for 1h. After melting, the product was filtered by water leaching to obtain filtrate. CO2 was introduced into the filtrate and the final pH was controlled to 10.0~11.0. Aluminum hydroxide was preferentially precipitated and calcined to obtain γ-Al2O3 (purity 98.5%), which was used to prepare Al-Ga-In-Sn hydrogen production alloy. After aluminum precipitation, the solution was acidified to obtain silica gel and prepared porous SiO2. The magnesium component in the molten residue was extracted by chlorination roasting-molten salt electrolysis to obtain metallic magnesium, which was used to prepare Mg-Ni hydrogen storage alloy.

[0029] 4) The remaining residue after extraction (mainly calcium silicate, incompletely dissolved aluminosilicate and trace elements) is applied to marginal land to plant switchgrass.

[0030] The core innovation of this invention lies in systematically revealing and utilizing the synergistic mechanism of fly ash-coal gangue-cement-based composite materials in "soil service, in-situ activation, element recovery, and hydrogen energy material preparation." Its scientific basis can be understood from four closely related levels: First, the aluminum (Al2O3 content 15%-35%) and magnesium (MgO content 1%-5%) abundant in fly ash and coal gangue are core strategic elements of the hydrogen energy industry chain: aluminum can react with water to generate hydrogen (2Al+6H2O→2Al(OH)3+3H2), making it an ideal chemical hydrogen production material. By alloying with low-melting-point metals (Ga, In, Sn), the surface oxide film barrier can be removed, enabling controlled hydrogen release at room temperature; magnesium can reversibly absorb and release hydrogen (Mg+H2↔MgH2), with a theoretical hydrogen storage capacity of up to 7.6wt%, making it a highly promising solid hydrogen storage material.

[0031] Secondly, the introduction of cement components fundamentally reshapes the microstructure and service performance of the solid waste matrix, playing a synergistic role in framework construction, pore connectivity, and alkali-activated pre-activation. The gel product formed by cement hydration (CSH gel) can form a continuous and dense cemented network, firmly encapsulating spherical fly ash particles and coal gangue fragments. This not only significantly improves the overall strength of the material but also ensures that it maintains its blocky morphology during service and recycling crushing, greatly facilitating subsequent recycling operations. Simultaneously, the natural nanoscale pores (2-50 nm) within the CSH gel are interconnected with the micron-scale macropores (50-200 μm) formed by aluminum powder foaming, constituting multi-level mass transfer channels. This creates a smooth path for efficient penetration and ion diffusion of the leachate during subsequent element extraction. Furthermore, the highly alkaline environment (pH 12-13) created by cement hydration can continuously erode the aluminosilicate glass in the solid waste, partially activating Al and Mg elements before soil service, laying the foundation for subsequent plant-microbe pre-activation.

[0032] Furthermore, the unique contribution of fly ash-gangue-cement-based materials. When the material is immersed in zinc sulfate solution, the following reaction occurs: Zn 2+ +Ca(OH)2+SO4 2- +H2O→CaSO4·2H2O (gypsum) +Zn4SO4(OH)6·nH2O (basic zinc sulfate, ZSH), as Figure 3 The microscopic mechanism explained. This process produces a dual effect: strength enhancement: the generated gypsum and ZSH crystals fill the pores, refining the pore structure and further increasing the material's compressive strength by 20%-30%; interface activation: the growth process of ZSH crystals can "leverage" the aluminosilicate framework, generating more microcracks and fresh surfaces, creating more reaction sites for subsequent element extraction—this is precisely the microscopic mechanism of "activation upon service".

[0033] Finally, the construction logic of the "agriculture-industry" cascade closed loop. During the service of the plant retention system, the materials undergo the following synergistic effects: Plant root activation: Organic acids such as citric acid and oxalic acid secreted by the roots can complex and dissolve CSH gel and the surface of aluminosilicate minerals, forming soluble Al-organic complexes, equivalent to a mild "in-situ acid leaching". Microbial metabolic activation: Organic acids, iron carriers, and extracellular polymers produced by rhizosphere microbial metabolism can change the local microenvironment pH and redox potential, inducing mineral phase transitions and transforming Al and Mg into more easily extracted forms. Wet-dry cycle activation: Periodic wet-dry cycles trigger the dissolution-reprecipitation process of minerals, combined with the expansion and contraction characteristics of cement hydration products, generating a large number of lattice defects and microcracks. The recovered residue is rich in incompletely dissolved calcium silicate, aluminosilicate fragments, and trace elements. After returning to farmland: it improves acidic soil (residual alkaline substances), replenishes beneficial elements such as silicon and calcium, improves soil aggregate structure, and provides a growth substrate for energy crops. Energy crops (such as switchgrass) have advantages such as large biomass, strong stress resistance, and the ability to be planted on marginal land. Their harvest can be used to produce biochar through pyrolysis (which can be further used for soil improvement or catalyst carriers), or to produce hydrogen through gasification / fermentation, thus realizing the green conversion of "solar energy → biomass → hydrogen energy".

[0034] Compared with the prior art, the present invention has the following beneficial effects: (1) The porous composite material provided by the present invention is prepared from a composite of fly ash and coal gangue, cement, decomposed humus from garden leaves, aluminum powder, starch, ammonium sulfate, and quartz sand as raw materials. The introduction of the cement component has a triple function of structural reinforcement, ion channel construction, and alkali activation synergy, giving the material both excellent mechanical properties (compressive strength 5-15 MPa) and high porosity (35%-50%), meeting the structural requirements of the plant retention system media layer and facilitating complete recycling. Furthermore, the presence of cement increases the subsequent aluminum leaching rate after soil use by more than 25% compared to the control group without cement.

[0035] (2) The method for preparing porous composite materials provided by the present invention. Hydrogen gas is generated by the reaction of aluminum powder foaming agent with the alkaline environment produced by cement hydration to form initial macropores; then, in conjunction with starch gelatinization and low-temperature foaming with ammonium sulfate, secondary foaming is carried out under the action of residual heat from coke oven flue gas to construct a multi-level porous structure; finally, the cured material is immersed in zinc sulfate solution for activation, and the mechanical properties are further improved and the interface is activated by utilizing the "pore refinement effect".

[0036] (3) The porous composite material provided by the present invention serves as a functional filler layer for plant retention systems. While purifying copper pollution in rainwater, it also enables aluminum and magnesium elements in the material to undergo plant-microbe synergistic pre-activation in the soil microenvironment, laying the foundation for subsequent resource recycling.

[0037] (4) Constructing a cascaded resource recovery path of "agriculture-industry". Copper is recovered first; after the material is activated in zinc sulfate solution, its porous structure and interfacial activity are significantly improved, laying the foundation for the efficient extraction of aluminum and magnesium. Aluminum, magnesium and silicon are extracted by utilizing the pre-activation effect and the through-holes constructed by cement; aluminum and magnesium are used to prepare aluminum-based hydrogen production materials and magnesium-based hydrogen storage alloys, respectively; the residue after extraction is returned to farmland to improve the soil and plant energy crops, forming a complete material cycle and realizing "industrial solid waste → environmental treatment → hydrogen energy materials → agricultural improvement" (e.g. Figure 4 The complete material cycle (as shown) significantly reduces the carbon footprint and greatly improves resource efficiency, providing a replicable innovative paradigm for the circular economy under the "dual carbon" goal. Attached Figure Description

[0038] The above and other objects, features, and advantages of the invention will be apparent from the following description of preferred embodiments illustrating the gist of the invention and its use, and the accompanying drawings, in which: Figure 1 This is a flowchart illustrating the preparation process of the porous composite material of the present invention.

[0039] Figure 2 This is a schematic diagram of the plant retention system in Example 2.

[0040] Figure 3 This is a schematic diagram of the mechanism of the porous composite material of the present invention.

[0041] Figure 4 This is a flowchart of the "agriculture-industry" cascaded closed-loop system in this invention. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The embodiments of this application are only examples, and all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example 1 1) Raw material preparation: A composite of fly ash and coal gangue: Take fly ash and coal gangue crushed to below 100 mesh, sieve through an 8-10 mesh, and mix them at a weight ratio of 7:3. Place the mixture in a 1.0 mol / L sodium hydroxide solution (the ratio of the total mass of fly ash and coal gangue to the amount of sodium hydroxide solution is 1 g: 5 mL), soak at room temperature for 10 days, wash until pH≈8, and dry for later use.

[0044] Ordinary Portland cement: Grade 42.5R.

[0045] Humus: made from composted garden leaves, with an organic matter content of 45% and a pH of 6.5.

[0046] Aluminum powder: Industrial grade, particle size 20-50 μm.

[0047] Others: corn starch, industrial grade ammonium sulfate, quartz sand.

[0048] 2) Preparation process as follows Figure 1 As shown, the ingredients and mixing are as follows: Weigh the ingredients according to the weight ratio of fly ash and coal gangue composite: cement: humus: aluminum powder: starch: ammonium sulfate: quartz sand = 50: 20: 10: 0.2: 6: 2: 5, and mix thoroughly.

[0049] 3) Initial foaming of aluminum powder: Add water to the mixture to adjust the moisture content to 30%, stir quickly for 30 seconds and then pour into the mold. Let it stand at room temperature (25°C) for 20 minutes to foam. The aluminum powder reacts with the alkaline environment to generate hydrogen gas and form the initial pores.

[0050] Secondary foaming with residual heat: The initially foamed preform is placed in a coke oven flue gas atmosphere at 260℃ and reacted for 6 minutes. Starch gelatinization and ammonium sulfate decomposition work together to foam, forming a multi-level porous structure.

[0051] 5) Curing: After demolding, cure in a standard curing box (20℃, 95% humidity) for 28 days.

[0052] 6) Activation treatment: Immerse the cured material in a 1.0 mol / L zinc sulfate solution (the ratio of cured material to zinc sulfate solution is 1 g: 15 mL) for 36 hours, then remove and dry at 50°C to obtain the finished product.

[0053] 7) Performance Testing: Compressive strength (according to standard GB / T 17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)"): 12.3 MPa (28 days); Porosity: 48%; For Cu 2+ Saturated adsorption capacity: 42 mg / g; In subsequent alkaline leaching extraction, the aluminum leaching rate of the activated material increased by 35% compared to the unactivated material, confirming that the activation treatment significantly enhanced the extractability of elements.

[0054] Control group 1 (no cement control group): Using the same raw material system and proportions as the present invention, only the cement component is removed, and fly ash-coal gangue composite is used as the main skeleton, while the remaining components (humus, aluminum powder, starch, ammonium sulfate, quartz sand) and preparation process conditions remain the same.

[0055] Control group 2 (low-alkaline structure control group): The cement components were replaced with an equal mass of fly ash to eliminate the influence of alkali activation and hydration products on pore structure and element activation, while keeping all other conditions the same.

[0056] Experimental results show that: Compared with control group 1, the aluminum leaching rate of the material of the present invention is increased by more than 25% because the cement hydration generates CSH gel to construct through channels and form a continuous alkaline environment, which pre-activates the aluminosilicate structure. Compared with control group 2, this demonstrates that the improvement is not a simple filler effect, but rather a result of the synergistic effect of the structure and chemistry of cement hydration products.

[0057] Example 2: Application of materials in plant retention systems and verification of pre-activation effect A plant retention system (structure as follows) near the industrial area Figure 2 As shown, a 35cm thick functional layer made of the material obtained in Example 1 is filled in the middle, and reeds are planted on the top layer. The plant retention system includes, from top to bottom, a vegetation layer, a planting soil layer, a functional layer, a geotextile layer, and a drainage layer.

[0058] Monitoring showed that the average removal rate of total copper in rainwater runoff reached 95%; after one year of operation, sampling analysis showed that the characteristic peaks of some aluminosilicate mineral phases were weakened by XRD; comparative tests showed that under the same extraction conditions, the Al leaching rates of the material after one year of service were 82% and 41% respectively, confirming a significant pre-activation effect.

[0059] Example 3: Cascaded Resource Recovery of Saturated Materials 1) Material Removal and Pretreatment: The porous composite material, which had reached copper adsorption saturation after two years of operation, was removed and crushed to a particle size of less than 1 cm. The material was in block form with no obvious powdering (thanks to cement reinforcement).

[0060] 2) Priority recovery of copper: The powder is placed in a sulfuric acid solution with pH=2.0 and leached at 50℃ for 2 hours to obtain copper leaching solution and copper leaching residue. The copper leaching rate is 92%. The leaching solution is electrolyzed to recover metallic copper.

[0061] 3) Stepwise separation of aluminum, silicon, and magnesium: The copper leaching residue was mixed with NaOH at a mass ratio of 1:1 and melted at 600℃ for 1 hour. After melting, the resulting product was filtered after water leaching to obtain a filtrate rich in sodium aluminate and sodium silicate. CO2 was introduced into the filtrate, and the final pH was controlled to 10.0~11.0. Aluminum hydroxide was preferentially precipitated, and calcination yielded γ-Al2O3 (purity 98.5%), which was used to prepare Al-Ga-In-Sn hydrogen production alloy. After aluminum precipitation, the solution was acidified to obtain silica gel, and porous SiO2 (specific surface area 520 m²) was prepared. 2 / g); Magnesium components in the molten residue are extracted into metallic magnesium by chlorination roasting and molten salt electrolysis, which is then used to prepare Mg-Ni hydrogen storage alloys.

[0062] 4) Returning residue to farmland: The remaining residue after extraction (mainly composed of calcium silicate, incompletely dissolved aluminosilicate and trace elements) is naturally air-dried and then crushed to a particle size of less than 2 mm. It is then applied evenly to the surface layer of marginal land (0~20 cm) at a mass ratio of 5% (residue / soil). After tilling and mixing, switchgrass is planted.

[0063] To evaluate its agricultural effects, a control group was set up as follows: the control group consisted of marginal soil of the same type without the applied residue, subjected to the same tillage treatment, with all other conditions kept consistent. The same plot of land was selected to divide the experimental and control areas, each with an area of ​​10 m². 2 Three parallel replicates were set up; the seeding density of switchgrass was 8 kg / ha, the growth cycle was 120 days, and no additional fertilizer was applied during the period, and it was grown only under natural rainfall conditions. The test results showed that the aboveground dry weight of the control group was 8.6 ± 0.5 t / ha, while that of the experimental group was 11.6 ± 0.7 t / ha; the biomass increased by about 35%.

[0064] 5) Resource utilization of energy crops: After harvesting switchgrass, partial pyrolysis is used to prepare biochar (specific surface area 380 m²). 2 / g, which can be used as an adsorbent material or catalyst support), partially produces hydrogen through gasification (hydrogen production rate 0.8 m). 3 / kg biomass).

[0065] Although preferred embodiments of the invention have been shown and described, it is conceivable that those skilled in the art can devise various modifications to the invention within the spirit and scope of the appended claims.

Claims

1. A porous composite material, characterized by, The raw materials include the following parts by weight: A composite of fly ash and coal gangue, 45-60 parts. 15-25 parts cement 5-15 parts of humus 0.1~0.5 parts aluminum powder, 3-8 parts starch 1-3 parts ammonium sulfate 2-8 parts of quartz sand; The composite material of fly ash and coal gangue is a material obtained by soaking fly ash and coal gangue in an alkaline solution. The humus contains ≥35wt% organic matter and has a pH of 6~7.

5.

2. The porous composite material of claim 1, wherein, The preparation of the composite of fly ash and coal gangue includes the following steps: Fly ash and crushed coal gangue were mixed and then soaked in sodium hydroxide solution for modification. After soaking, the mixture was washed and dried.

3. The porous composite material of claim 2, wherein, The mass ratio of the fly ash to the coal gangue is (60~90):(10~40). The ratio of the total mass of the fly ash and the coal gangue to the amount of sodium hydroxide solution is 1g:(3~8)mL; The concentration of the sodium hydroxide solution is 0.5~2 mol / L; The soaking temperature is 10~30℃, and the soaking time is 7~14 days.

4. The porous composite material of claim 2, wherein, The cement includes ordinary Portland cement; The humus is obtained from fallen leaves through composting.

5. A method for preparing a porous composite material according to any one of claims 1 to 4, characterized in that, Includes the following steps: A mixture of fly ash and coal gangue, cement, humus, aluminum powder, starch, ammonium sulfate, and quartz sand is prepared to obtain a mixture. After grinding and sieving the mixture, it is placed in a molding mold, then water is sprayed into the mixture, and it is allowed to stand and foam to obtain a foamed preform. The foamed preform is placed in a drying device and heat-treated with coke oven flue gas to allow the foamed preform to foam a second time and be shaped to obtain a foamed body. The foamed material is cured, and the cured material is immersed in zinc sulfate solution for activation to obtain a porous composite material.

6. The method for preparing porous composite materials according to claim 5, characterized in that, The sieve opening is 8-10 mesh; The sprayed water reduces the moisture content of the mixture to 25%~35%. The time for standing foaming is 10-30 minutes.

7. The method for preparing porous composite materials according to claim 5, characterized in that, The temperature of the coke oven flue gas is 200~300℃; The heat treatment time is 5-10 minutes; The curing conditions are: temperature 18~22℃, humidity ≥95%, and time 7~28 days; The concentration of the zinc sulfate solution is 0.5~2 mol / L; The ratio of the cured material to zinc sulfate solution is 1g:(5~20)mL. The soaking and activation temperature is 10~30℃, and the soaking and activation time is 24~48h.

8. The use of the porous composite material according to any one of claims 1 to 4 in removing copper contaminants from rainwater runoff.

9. The application according to claim 8, characterized in that, The applications include: The porous composite material is incorporated into the functional layer of the plant retention system to adsorb copper pollutants in rainwater runoff. In the plant retention system, the functional layer is laid below the planting soil layer and above the drainage layer.

10. The application according to claim 8, characterized in that, Once the porous composite material becomes saturated with copper contaminants, it is recycled as a resource. The resource recycling method includes: a) The porous composite material saturated with adsorbed copper contaminants was removed, crushed, and powdered. b) Selective leaching and recovery of copper using hydrometallurgical methods; c) Utilizing the pre-activation effect formed by the material during its service in the soil and the through-hole structure constructed by cement hydration products, aluminum, magnesium, and silicon elements are extracted from the residue after copper leaching. d) The extracted aluminum and magnesium elements will be used as raw materials for preparing aluminum-based hydrogen production materials and magnesium-based hydrogen storage alloys, respectively. e) The remaining residue after extraction is returned to farmland as a soil conditioner for planting energy crops.

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