A method for producing building material substrates from municipal solid waste incineration and its preparation process.

Abstract

This invention discloses a method for producing building material substrates from municipal solid waste incineration waste and its preparation process. The substrate consists of 30-50 wt% fly ash, 20-40 wt% bottom ash, 10-20 wt% silicate cement, 3-10 wt% Fe-N-C@Cu-NPs modifier, and 5-15 wt% water. The fly ash is washed with water and heat-treated at 600-800℃ to remove chlorides and organic matter. The bottom ash is screened and magnetically separated to control particle size and iron content. Fe-N-C@Cu-NPs are prepared by high-temperature pyrolysis and wet chemical methods, catalyzing dioxin decomposition and heavy metal solidification. The preparation process includes pretreatment, mixing, vibration molding (5-10 MPa), and wet curing (20-35℃, 80-95% humidity, 7-21 days). The substrate has a compressive strength of 11.8-14.0 MPa, a dioxin content of less than 0.1 ng-TEQ / kg, a heavy metal curing rate of 96.5-98.5%, and a porosity of 10.5-12%, realizing the resource utilization of solid waste and achieving both environmental and economic benefits.

Description

Technical Field

[0001] This invention relates to the technical field of building material substrates, and in particular to a method for producing building material substrates using municipal solid waste incineration waste and its preparation process. Background Technology

[0002] Utilizing fly ash and bottom ash from municipal solid waste incineration to produce building material substrates is an important technological path for realizing the resource utilization of solid waste, and it has received much attention in the fields of environmental protection and building materials in recent years. Existing technologies mainly transform incineration fly ash into building material substrates suitable for walls, paving bricks, or concrete admixtures through processes such as mechanical ball milling, water washing to remove chlorine, conditioning and solidifying heavy metals, pulping and molding, and curing. Chinese patent (publication number: CN108083755A) discloses a method for manufacturing residential building materials from municipal solid waste incineration fly ash. Mechanical ball milling partially breaks down organic pollutants (such as dioxins) in the fly ash, water washing removes soluble chlorides, and then heavy metals are solidified using a polypolymer gel (such as calcium silicate hydrate, CSH), producing building material products with a compressive strength of 10-15 MPa. These technologies, through the synergistic effect of multiple processes, have initially realized the resource utilization of fly ash, providing a feasible solution for solid waste reduction and the diversification of building materials. While the aforementioned technologies have made some progress in the utilization of fly ash in building materials, they still have significant shortcomings in the treatment of dioxins (polychlorinated dibenzo-p-dioxins / furans, PCDD / Fs) and the control of byproducts. Dioxin molecules have a stable aromatic ring structure and C-Cl bonds, requiring high energy input to break. Mechanical ball milling provides kinetic energy through particle collisions and shear forces, but the energy distribution is random and non-specific. Most of the energy is dissipated in the physical breakage and surface morphology changes of fly ash particles, rather than concentrated in the chemical breaking of C-Cl bonds, resulting in generally low dioxin decomposition efficiency. Furthermore, the non-selective reactions induced by mechanical energy easily degrade dioxins into carbon residues or low-molecular-weight chlorinated organic compounds. These byproducts not only increase the processing load of subsequent washing and conditioning processes but may also pose a risk of secondary pollution during environmental release. Summary of the Invention

[0003] This application provides a building material substrate produced from municipal solid waste incineration waste, the building material substrate being composed of the following components by weight percentage:

[0004] Municipal solid waste incineration fly ash: 30-50 wt%

[0005] Municipal solid waste incineration bottom ash: 20-40 wt%

[0006] Silicate cement: 10-20 wt%

[0007] Fe-NC@Cu-NPs: 3-10wt%;

[0008] Water: 5-15 wt%.

[0009] It should be noted that the building material substrate is provided by aluminosilicate and heavy metal sources from municipal solid waste incineration fly ash (30-50 wt%), bottom ash (20-40 wt%) as coarse aggregate to enhance structural stability, silicate cement (10-20 wt%) as a binder to generate CSH gel through hydration reaction to provide strength, and water (5-15 wt%) to regulate slurry fluidity and promote hydration. Fe-NC@Cu-NPs (3-10 wt%) is a key modifier; its single-atom Fe-N4 sites adsorb and activate oxygen to generate reactive oxygen species, effectively decomposing dioxins. Cu nanoparticles catalyze C-Cl bond breaking to accelerate dechlorination, and the high specific surface area nitrogen-carbon carrier enhances the solidification rate of heavy metals (such as Pb and Cd). Simultaneously, it optimizes the substrate microstructure and reduces the expansion effect of free CaO / MgO, thereby improving compressive strength and durability.

[0010] As a preferred technical solution for producing building material substrates from municipal solid waste incineration waste, the municipal solid waste incineration fly ash undergoes pretreatment, including the following steps:

[0011] More than 90% of soluble chloride salts in municipal solid waste incineration fly ash are removed by water washing, and organic pollutants are removed by heat treatment at 600-800℃ for 1-2 hours.

[0012] It should be noted that more than 90% of the soluble chloride salts in the fly ash from municipal solid waste incineration are removed by water washing, and organic pollutants are effectively removed by heat treatment at 600-800℃ for 1-2 hours.

[0013] As a preferred technical solution for producing building material base material from municipal solid waste incineration waste, the municipal solid waste incineration bottom ash is screened and magnetically separated, with the particle size controlled between 0.25 mm and 5 mm and the iron content less than 1 wt%.

[0014] It should be noted that the purpose of screening and magnetic separation of the municipal solid waste incineration bottom ash is to optimize its physical and chemical properties for use as aggregate in building material substrates: screening controls the particle size to 0.25-5 mm through mechanical separation, and uses the principle of particle gradation to ensure uniform distribution of aggregates, thereby enhancing the density and compressive strength of the substrate; magnetic separation uses the principle of ferromagnetism to remove iron-containing impurities, reduce the volume expansion and microcracks caused by iron oxides, and at the same time reduce the potential catalytic activity on dioxin regeneration, thereby improving the long-term stability and durability of the substrate.

[0015] As a preferred technical solution for producing building material substrates from municipal solid waste incineration, the nitrogen-doped carbon carrier has a specific surface area of ​​500-1200 m². 2 / g, nitrogen content is 5-15 wt%.

[0016] It should be noted that the high specific surface area provides abundant adsorption sites, which enhances the solidification of heavy metals (such as Pb and Cd) and the decomposition of dioxins in fly ash and bottom slag. The doping of nitrogen atoms optimizes the coordination environment of Fe-N4 single atoms through electronic effects, thereby improving their oxygen activation ability. The dispersibility of Cu nanoparticles is also improved due to the anchoring of nitrogen enrichment sites, thus synergistically catalyzing the breaking of C-Cl bonds and the optimization of the substrate microstructure, ultimately improving compressive strength and stability.

[0017] In addition, this application provides a preparation process for producing building material substrates using municipal solid waste incineration waste, including the following steps:

[0018] Step S1: Pre-treat the fly ash and bottom ash from municipal solid waste incineration to obtain pre-treated fly ash and pre-treated bottom ash;

[0019] Step S2: Preparation of the modifier Fe-NC@Cu-NPs: Nitrogen-doped carbon support was prepared by high-temperature pyrolysis, and single-atom iron and copper nanoparticles were loaded onto the support using a wet chemical method;

[0020] Step S3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water and stir to form a homogeneous slurry;

[0021] Step S4: Inject the slurry into the mold and use a vibration molding process with a molding pressure of 5-10 MPa;

[0022] Step S5: Curing at a temperature of 20-35℃ and a humidity of 80-95% for 7-21 days yields the building material substrate.

[0023] It should be noted that free CaO / MgO in fly ash and bottom ash reacts with SiO2 through water washing and heat treatment to form stable silicates. Sieving and magnetic separation optimize the particle size and purity of the bottom ash to reduce the impact of expansion and impurities. The high specific surface area and nitrogen coordination sites of the nitrogen-doped carbon support enhance the oxygen activation of Fe-N4 single atoms and the catalytic breaking of C-Cl bonds in Cu nanoparticles, promoting the solidification of heavy metals and the decomposition of dioxins. Furthermore, the nitrogen-doped carbon support provides abundant adsorption sites to capture free CaO / MgO particles. Fe-N4 single atoms are activated by oxygen to generate active oxygen species, catalyzing the reaction of CaO / MgO with SiO2 or Al2 in the substrate. O3 reaction generates stable silicates (such as CaSiO3) or magnesium aluminum spinel (MgAl2O4), reducing the formation of expansive hydroxides (such as Ca(OH)2, Mg(OH)2). Cu nanoparticles further promote electron transfer on the CaO / MgO surface, accelerating its chemical bonding with surrounding components, inhibiting volume expansion and microcracks, thereby improving the compressive strength and long-term stability of the substrate. Silicate cement hydration reaction generates CSH gel. Vibration molding compacts the substrate structure through pressure and vibration, reducing porosity. Wet curing and natural curing conditions induce gel solidification and carbonization, synergistically improving compressive strength and durability.

[0024] As a preferred technical solution for the preparation process of building material substrates using municipal solid waste incineration waste, step S2, the preparation of Fe-NC@Cu-NPs includes:

[0025] Nitrogen-doped carbon support was prepared by pyrolysis using urea and glucose as precursors.

[0026] Fe-N4 sites were formed by impregnation with FeCl3 solution and heat treatment;

[0027] Copper nanoparticles are formed by reducing CuCl2 with NaBH4.

[0028] It should be noted that the process of preparing nitrogen-doped carbon support via pyrolysis using urea and glucose as precursors involves the decomposition of urea to release nitrogen atoms that embed into the carbon framework, forming pyridine nitrogen and pyrrole nitrogen coordination sites. Simultaneously, glucose is carbonized to generate a porous structure with a high specific surface area. Impregnation with FeCl3 solution followed by heat treatment allows Fe ions to coordinate with the nitrogen coordination sites, generating a stable Fe-N4 single-atom structure, which enhances oxygen activation capacity through electronic effects. During the reduction of CuCl2 by NaBH4, Cu... 2+ Reduced to Cu0 nanoparticles (2-5 nm), they are uniformly dispersed under the anchoring of nitrogen-enriched sites, synergistically catalyzing the breaking of C-Cl bonds and the solidification of heavy metals at Fe-N4 sites, thereby optimizing the catalytic performance of Fe-NC@Cu-NPs.

[0029] As a preferred technical solution for the preparation process of building material substrates using municipal solid waste incineration, the stirring in step 3 is carried out using a twin-shaft mixer with a speed of 100-200 rpm and a stirring time of 10-20 minutes.

[0030] It should be noted that the pretreated fly ash, bottom slag, silicate cement, and Fe-NC@Cu-NPs modifier should be thoroughly mixed with water to form a uniform slurry.

[0031] As a preferred technical solution for the preparation process of building material substrates using municipal solid waste incineration, the vibration frequency of the vibration molding process in step S4 is 30-50 Hz and the vibration time is 1-3 minutes.

[0032] It should be noted that mechanical vibration effectively removes air bubbles from the slurry, optimizes particle distribution and density, thereby improving the compressive strength and structural stability of the substrate.

[0033] As a preferred technical solution for the preparation process of building material substrates using municipal solid waste incineration waste, the dioxin content of the building material substrate is less than 0.1 ng-TEQ / kg.

[0034] It should be noted that the dioxin content of the building material substrate is less than 0.1 ng-TEQ / kg, indicating that the Fe-NC@Cu-NPs modifier efficiently decomposes dioxins in fly ash and bottom slag through the oxygen activation of its Fe-N4 single atoms and the catalytic breaking of C-Cl bonds in Cu nanoparticles, ensuring that the substrate meets strict environmental protection standards and reducing potential toxicity risks.

[0035] This application utilizes municipal solid waste incineration fly ash (30-50 wt%) and bottom ash (20-40 wt%) as main raw materials, combined with silicate cement (10-20 wt%) and Fe-NC@Cu-NPs modifier (3-10 wt%), to achieve efficient resource utilization of solid waste. This significantly reduces dioxin content to 0.05-0.09 ng-TEQ / kg, far below the environmental standard (0.1 ng-TEQ / kg), and achieves a heavy metal (such as Pb and Cd) solidification rate of 96.5-98.5%. Fe-NC@Cu-NPs effectively decomposes dioxins and solidifies heavy metals through Fe-N4 single-atom site activation of oxygen and Cu nanoparticle catalytic C-Cl bond breaking. Simultaneously, it optimizes the substrate microstructure, reducing porosity to 10.5-12% and increasing compressive strength to 11.8-14.0 MPa. The optimized preparation process, including fly ash washing and heat treatment at 600-800℃, bottom ash screening and magnetic separation, vibration molding (30-50 Hz, 5-10 MPa), and wet curing (20-35℃, 80-95% humidity, 7-21 days), ensures the density of the substrate and the controllability of the process. This technology transforms hazardous waste into high-performance building material substrates, suitable for walls, paving bricks, etc., and has significant environmental, economic, and social benefits, providing an efficient and environmentally friendly solution for the resource utilization of waste from waste incineration. Attached Figure Description

[0036] Figure 1 The C1s XPS spectrum of the Fe-NC@Cu-NPs modifier in Example 1;

[0037] Figure 2 The N 1s XPS spectrum of the Fe-NC@Cu-NPs modifier in Example 1;

[0038] Figure 3 The Fe 2p XPS spectrum of the Fe-NC@Cu-NPs modifier in Example 1;

[0039] Figure 4 The Cu 2p XPS spectrum of the Fe-NC@Cu-NPs modifier in Example 1;

[0040] Figure 5 The image shows the O 1s XPS spectrum of the Fe-NC@Cu-NPs modifier in Example 1. Detailed Implementation

[0041] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0042] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0043] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments. Example Example 1

[0044] Example 1 provides a method for producing building material substrates from municipal solid waste incineration waste and its preparation process, wherein the building material substrate is composed of the following components by weight percentage:

[0045] Municipal solid waste incineration fly ash: 30 wt%

[0046] Municipal solid waste incineration bottom ash: 25 wt%;

[0047] Silicate cement: 10 wt%

[0048] Fe-NC@Cu-NPs: 3wt%;

[0049] Water: 10 wt%.

[0050] The preparation method of the high-performance silicone rubber composition includes the following technical steps:

[0051] Step 1: The fly ash from municipal solid waste incineration is washed with water to remove more than 90% of soluble chlorides, and then heat-treated at 800℃ for 1 hour to remove organic pollutants; the bottom ash from municipal solid waste incineration is screened and magnetically separated, with the particle size controlled at 0.25-5 mm and the iron content below 1 wt%.

[0052] Step 2: Preparation of the modifier Fe-NC@Cu-NPs: Using urea and glucose (mass ratio 2:1) as precursors, nitrogen-doped carbon support (NC) was prepared by pyrolysis at 900℃ for 2 hours under a nitrogen atmosphere, with a specific surface area of ​​800-1200 m². 2 / g, nitrogen content is 8-12 wt%;

[0053] Subsequently, the NC carrier was dispersed in deionized water, and FeCl3 solution (Fe content 0.5-2 wt%) was added. The mixture was stirred at 80℃ for 4 hours by wet chemical impregnation, and then heat-treated at 800℃ under a nitrogen atmosphere for 1 hour to form Fe-N4 single-atom sites. Next, Fe-NC was dispersed in ethanol, and CuCl2 solution (Cu content 1-5 wt%) was added. NaBH4 solution (concentration 0.1 mol / L) was added dropwise for reduction. The reaction temperature was controlled at 25℃, and the mixture was stirred for 2 hours to allow copper nanoparticles to be loaded in situ onto the carrier surface. Finally, the Fe-NC@Cu-NPs modifier was obtained by centrifugation, washing (3 times each with deionized water and ethanol), and vacuum drying at 60℃ for 8 hours.

[0054] Step 3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water, and stir using a twin-shaft mixer at a speed of 200 rpm for 10 minutes to form a homogeneous slurry.

[0055] Step S4: Inject the homogeneous slurry prepared in step S3 into a stainless steel mold, and use a vibration molding process with a vibration frequency of 30Hz for 3 minutes to remove air bubbles. Apply a pressure of 10 MPa for 60 seconds to promote particle compaction.

[0056] Step S5: Place the molded blank in a curing room at a temperature of 20°C and a humidity of 95% for 15 days to obtain the building material substrate. Example 2

[0057] Example 2 provides a method for producing building material substrates from municipal solid waste incineration waste and its preparation process, wherein the building material substrate is composed of the following components by weight percentage:

[0058] Municipal solid waste incineration fly ash: 40 wt%

[0059] Municipal solid waste incineration bottom ash: 40 wt%

[0060] Silicate cement: 15wt%

[0061] Fe-NC@Cu-NPs: 10wt%

[0062] Water: 15 wt%.

[0063] The preparation method of the high-performance silicone rubber composition includes the following technical steps:

[0064] Step 1: The fly ash from municipal solid waste incineration is washed with water to remove more than 90% of soluble chlorides, and then heat-treated at 600℃ for 2 hours to remove organic pollutants; the bottom ash from municipal solid waste incineration is screened and magnetically separated, with the particle size controlled at 0.25-5 mm and the iron content below 1 wt%.

[0065] Step 2: Preparation of the modifier Fe-NC@Cu-NPs: Using urea and glucose (mass ratio 2:1) as precursors, nitrogen-doped carbon support (NC) was prepared by pyrolysis at 900℃ for 2 hours under a nitrogen atmosphere, with a specific surface area of ​​800-1200 m². 2 / g, nitrogen content is 8-12 wt%;

[0066] Subsequently, the NC carrier was dispersed in deionized water, and FeCl3 solution (Fe content 0.5-2 wt%) was added. The mixture was stirred at 80℃ for 4 hours by wet chemical impregnation, and then heat-treated at 800℃ under a nitrogen atmosphere for 1 hour to form Fe-N4 single-atom sites. Next, Fe-NC was dispersed in ethanol, and CuCl2 solution (Cu content 1-5 wt%) was added. NaBH4 solution (concentration 0.1 mol / L) was added dropwise for reduction. The reaction temperature was controlled at 25℃, and the mixture was stirred for 2 hours to allow copper nanoparticles to be loaded in situ onto the carrier surface. Finally, the Fe-NC@Cu-NPs modifier was obtained by centrifugation, washing (3 times each with deionized water and ethanol), and vacuum drying at 60℃ for 8 hours.

[0067] Step 3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water, and stir using a twin-shaft mixer at a speed of 150 rpm for 20 minutes to form a homogeneous slurry.

[0068] Step 4: Inject the homogeneous slurry prepared in step 3 into a stainless steel mold, and use a vibration molding process with a vibration frequency of 50Hz for 1 minute to remove air bubbles. Apply a pressure of 5 MPa for 60 seconds to promote particle compaction.

[0069] Step 5: Place the molded blank in a curing room at a temperature of 35℃ and a humidity of 80% for 21 days to obtain the building material substrate. Example 3

[0070] Example 3 provides a method for producing building material substrates from municipal solid waste incineration waste and its preparation process, wherein the building material substrate is composed of the following components by weight percentage:

[0071] Municipal solid waste incineration fly ash: 50 wt%

[0072] Municipal solid waste incineration bottom ash: 20 wt%

[0073] Silicate cement: 10 wt%

[0074] Fe-NC@Cu-NPs: 8wt%

[0075] Water: 5 wt%.

[0076] The preparation method of the high-performance silicone rubber composition includes the following technical steps:

[0077] Step 1: The fly ash from municipal solid waste incineration is washed with water to remove more than 90% of soluble chlorides, and then heat-treated at 700℃ for 2 hours to remove organic pollutants; the bottom ash from municipal solid waste incineration is screened and magnetically separated, with the particle size controlled at 0.25-5 mm and the iron content below 1 wt%.

[0078] Step 2: Preparation of the modifier Fe-NC@Cu-NPs: Using urea and glucose (mass ratio 2:1) as precursors, nitrogen-doped carbon support (NC) was prepared by pyrolysis at 900℃ for 2 hours under a nitrogen atmosphere, with a specific surface area of ​​800-1200 m². 2 / g, nitrogen content is 8-12 wt%;

[0079] Subsequently, the NC carrier was dispersed in deionized water, and FeCl3 solution (Fe content 0.5-2 wt%) was added. The mixture was stirred at 80℃ for 4 hours by wet chemical impregnation, and then heat-treated at 800℃ under a nitrogen atmosphere for 1 hour to form Fe-N4 single-atom sites. Next, Fe-NC was dispersed in ethanol, and CuCl2 solution (Cu content 1-5 wt%) was added. NaBH4 solution (concentration 0.1 mol / L) was added dropwise for reduction. The reaction temperature was controlled at 25℃, and the mixture was stirred for 2 hours to allow copper nanoparticles to be loaded in situ onto the carrier surface. Finally, the Fe-NC@Cu-NPs modifier was obtained by centrifugation, washing (3 times each with deionized water and ethanol), and vacuum drying at 60℃ for 8 hours.

[0080] Step 3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water, and stir using a twin-shaft mixer at 100 rpm for 15 minutes to form a homogeneous slurry.

[0081] Step 4: Inject the homogeneous slurry prepared in step 3 into a stainless steel mold, and use a vibration molding process with a vibration frequency of 40Hz for 2 minutes to remove air bubbles. Apply a pressure of 8 MPa for 60 seconds to promote particle compaction.

[0082] Step 5: Place the molded blank in a curing room at 30°C and 90% humidity for 7 days to obtain the building material substrate. Example 4

[0083] Example 4 provides a method for producing building material substrates from municipal solid waste incineration waste and its preparation process, wherein the building material substrate is composed of the following components by weight percentage:

[0084] Municipal solid waste incineration fly ash: 30 wt%

[0085] Municipal solid waste incineration bottom ash: 40 wt%

[0086] Silicate cement: 20wt%

[0087] Fe-NC@Cu-NPs: 3wt%;

[0088] Water: 10 wt%.

[0089] The preparation method of the high-performance silicone rubber composition includes the following technical steps:

[0090] Step 1: The fly ash from municipal solid waste incineration is washed with water to remove more than 90% of soluble chlorides, and then heat-treated at 800℃ for 1 hour to remove organic pollutants; the bottom ash from municipal solid waste incineration is screened and magnetically separated, with the particle size controlled at 0.25-5 mm and the iron content below 1 wt%.

[0091] Step 2: Preparation of the modifier Fe-NC@Cu-NPs: Using urea and glucose (mass ratio 2:1) as precursors, nitrogen-doped carbon support (NC) was prepared by pyrolysis at 900℃ for 2 hours under a nitrogen atmosphere, with a specific surface area of ​​800-1200 m². 2 / g, nitrogen content is 8-12 wt%;

[0092] Subsequently, the NC carrier was dispersed in deionized water, and FeCl3 solution (Fe content 0.5-2 wt%) was added. The mixture was stirred at 80℃ for 4 hours by wet chemical impregnation, and then heat-treated at 800℃ under a nitrogen atmosphere for 1 hour to form Fe-N4 single-atom sites. Next, Fe-NC was dispersed in ethanol, and CuCl2 solution (Cu content 1-5 wt%) was added. NaBH4 solution (concentration 0.1 mol / L) was added dropwise for reduction. The reaction temperature was controlled at 25℃, and the mixture was stirred for 2 hours to allow copper nanoparticles to be loaded in situ onto the carrier surface. Finally, the Fe-NC@Cu-NPs modifier was obtained by centrifugation, washing (3 times each with deionized water and ethanol), and vacuum drying at 60℃ for 8 hours.

[0093] Step 3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water, and stir using a twin-shaft mixer at a speed of 150 rpm for 10 minutes to form a homogeneous slurry.

[0094] Step 4: Inject the homogeneous slurry prepared in step 3 into a stainless steel mold, and use a vibration molding process with a vibration frequency of 40Hz for 3 minutes to remove air bubbles. Apply a pressure of 5MPa for 60 seconds to promote particle compaction.

[0095] Step 5: Place the molded blank in a curing room at a temperature of 30℃ and a humidity of 95% for 14 days to obtain the building material substrate.

[0096] Comparison Example

[0097] Compare with Example 1

[0098] The building material substrate formulation and preparation process of Comparative Example 1 and Example 1 are basically the same, but the Fe-NC@Cu-NPs modifier is replaced with an equal amount (3 wt%) of municipal solid waste incineration fly ash, that is, the formulation is adjusted as follows:

[0099] Municipal solid waste incineration fly ash: 33 wt% (original 30 wt% + replacement 3 wt%)

[0100] Municipal solid waste incineration bottom ash: 25 wt%

[0101] Silicate cement: 10 wt%

[0102] Water: 10 wt%

[0103] Preparation process:

[0104] Delete step S2 (preparation of Fe-NC@Cu-NPs modifier).

[0105] The remaining steps (S1, S3, S4, S5) are the same as in Example 1, including fly ash washing and heat treatment (800℃, 1 hour), bottom ash screening and magnetic separation, twin-shaft stirring (200 rpm, 10 minutes), vibration molding (30 Hz, 3 minutes, 10 MPa), and curing (20℃, 95% humidity, 15 days).

[0106] Compare with Example 2

[0107] The building material substrate formulation of Comparative Example 2 is the same as that of Example 1, but the wet chemical preparation step of Fe-NC@Cu-NPs is omitted in the preparation process. Instead, a simple physical mixing method is used to add Fe and Cu compounds, that is:

[0108] Building material base material formulation:

[0109] Municipal solid waste incineration fly ash: 30 wt%

[0110] Municipal solid waste incineration bottom ash: 25 wt%

[0111] Silicate cement: 10 wt%

[0112] A physical mixture of FeCl3 and CuCl2 (Fe:Cu mass ratio of 1:2, total amount 3 wt%): 3 wt%

[0113] Water: 10 wt%

[0114] Preparation process:

[0115] Steps S1, S3, S4, and S5 are the same as in Example 1.

[0116] Step S2 was changed to: directly physically mixing FeCl3 and CuCl2 powders (Fe:Cu mass ratio of 1:2) with nitrogen-doped carbon support (prepared by pyrolysis of urea and glucose, specific surface area of ​​800-1200 m2 / g, nitrogen content of 8-12 wt%) without wet chemical impregnation and NaBH4 reduction process.

[0117] The mixture is used directly in the slurry preparation of step S3.

[0118] Compare with Example 3

[0119] Comparative Example 3 uses the same building material substrate formulation as Example 1, but modifies the preparation process by eliminating the high-temperature heat treatment (600-800℃) in the pretreatment of incinerator fly ash. The formulation is as follows:

[0120] Municipal solid waste incineration fly ash: 30 wt%

[0121] Municipal solid waste incineration bottom ash: 25 wt%

[0122] Silicate cement: 10 wt%

[0123] Fe-NC@Cu-NPs: 3 wt%

[0124] Water: 10 wt%

[0125] Preparation process:

[0126] Step S1 (modified): The incineration fly ash was only washed with water to remove more than 90% of the soluble chlorides, without undergoing heat treatment at 600-800℃ for 1-2 hours to remove organic pollutants. The bottom ash was screened and magnetically separated according to Example 1 (particle size 0.25-5 mm, iron content <1 wt%).

[0127] Steps S2, S3, S4, and S5 are the same as in Example 1, including Fe-NC@Cu-NPs preparation, biaxial stirring (200 rpm, 10 minutes), vibration molding (30 Hz, 3 minutes, 10 MPa), and curing (20°C, 95% humidity, 15 days).

[0128] Compare with Example 4

[0129] Comparative Example 4 uses the same formula as Example 1, but the curing conditions are changed. The wet curing (20-35℃, 80-95% humidity, 7-21 days) is replaced with a shorter period of dry curing at room temperature. The formula is as follows:

[0130] Municipal solid waste incineration fly ash: 30 wt%

[0131] Municipal solid waste incineration bottom ash: 25 wt%

[0132] Silicate cement: 10 wt%

[0133] Fe-NC@Cu-NPs: 3 wt%

[0134] Water: 10 wt%

[0135] Preparation process:

[0136] Steps S1, S2, S3, and S4 are the same as in Example 1, including fly ash pretreatment (water washing and 800℃ heat treatment), bottom ash screening and magnetic separation, Fe-NC@Cu-NPs preparation, biaxial stirring (200 rpm, 10 minutes), and vibration molding (30 Hz, 3 minutes, 10 MPa).

[0137] Step S5 (modified): The formed preform is dry-cured for 7 days at room temperature (25℃, 50-60% humidity), instead of wet-curing for 7-21 days at 20-35℃ and 80-95% humidity.

[0138] Performance testing methods

[0139] 1. Compressive strength test

[0140] Test method: Refer to GB / T 17671-1999 "Test method for strength of cement mortar (ISO method)".

[0141] Steps: Prepare standard test blocks (e.g., 40 mm × 40 mm × 160 mm or cubic test blocks) according to the formulation and process of Examples 1-4 (vibration molding, wet curing for 7-21 days); apply uniform loading using a universal testing machine at a loading rate of 0.5-1.0 MPa / s, and record the maximum load when the test block fails.

[0142] Calculate compressive strength (MPa) = Maximum load (N) / Compressed area (mm²) 2 ).

[0143] 2. Dioxin content test

[0144] Test method: Refer to HJ77.2-2008 "Determination of dioxins in ambient air and exhaust gas by isotope dilution high-resolution gas chromatography-high-resolution mass spectrometry".

[0145] The steps involve sampling from the molded substrate and pulverizing it to a particle size of <0.25 mm; extracting dioxin-like compounds from the sample using an organic solvent (such as toluene), and adding an isotope-labeled internal standard (such as 13C-labeled PCDD / Fs); and quantitatively determining the concentrations of 17 toxic dioxin homologues by high-resolution gas chromatography-mass spectrometry (HRGC-HRMS) analysis and calculating the toxic equivalent (TEQ).

[0146] 3. Heavy metal curing rate test

[0147] Test method: Refer to GB 5085.3-2007 "Identification Standard for Hazardous Waste - Leaching Toxicity Identification".

[0148] Steps: Prepare a molded substrate sample and pulverize it to a particle size <9.5 mm; perform a toxicity leaching procedure (TCLP) using an acetic acid buffer solution (pH 2.88 or 4.93) with shaking for 18 hours (30 rpm); filter the leachate and determine the concentrations of heavy metals such as Pb and Cd using inductively coupled plasma mass spectrometry (ICP-MS).

[0149] The curing rate is calculated as follows: (Initial heavy metal content - content in leachate) / initial heavy metal content × 100%.

[0150] 4. Porosity testing

[0151] Test method: Refer to GB / T 21650.2-2008 "Determination of pore size distribution and porosity of solid materials by mercury porosimetry and gas adsorption method - Part 2: Analysis of mesopores and macropores by gas adsorption method".

[0152] Procedure: Take a molded substrate sample and dry it to constant weight. Use mercury indentation method (MIP) to determine the pore volume and pore size distribution, and calculate the total porosity = pore volume / total sample volume × 100%.

[0153] Table 1 shows the experimental data of Examples 1 to 4 and Control Examples 1 to 4.

[0154]

[0155] In conjunction with Example 1 and Figures 1 to 5 It can be seen that the C 1s spectrum shows sp 2The carbon (284.6 eV, intensity 0.50) predominant structure indicates that the graphitized carbon framework is the main body of the nitrogen-doped carbon support. CN bonds (286.2 eV, intensity 0.15) confirm nitrogen doping. CO (286.8 eV) and C=O (288.5 eV, intensities 0.10 each) reflect a small number of oxygen functional groups on the surface. π-π transitions (290.5 eV) verify the aromatic structure. The N 1s spectrum is dominated by pyridine nitrogen (398.5 eV, intensity 0.40) and Fe-N coordination (399.2 eV, intensity 0.20), with pyrrole nitrogen (400.2 eV, intensity 0.25) providing auxiliary stabilization. Graphitic nitrogen (401.2 eV) and nitrogen oxides (402.5 eV, lower intensity) enhance the conductivity and surface activity of the support. The Fe 2p spectrum is dominated by Fe-N4... The presence of predominantly single atoms (711.0 / 724.5 eV, intensities 0.60 / 0.30), with small amounts of Fe oxides (712.5 / 726.0 eV) and metallic Fe (707.0 / 720.5 eV, extremely low intensities), indicates single-atom dispersion; the Cu 2p spectrum is dominated by metallic Cu. 0 (932.6 / 952.4 eV, strength 0.70 / 0.35) predominates, with a small amount of Cu. 2+ (934.5 / 954.3 eV, including the satellite peak at 943 eV) and Cu + (932.8 / 952.6 eV) reflects surface oxidation; the O 1s spectrum is dominated by CO / C=O (532.0 eV, intensity 0.60), with metal oxides (530.0 eV) and adsorbed oxygen / water (533.5 eV, each intensity 0.20) contributing to surface chemistry. These functional groups and chemical states synergistically enhance the modifier's performance: CN and pyridine nitrogen provide high specific surface areas (800-1200 m²). 2 / g) and active sites promote the adsorption and solidification of heavy metals (such as Pb 96.5-98.0%, Cd 97.2-98.5%); Fe-N4 single-atom sites catalyze oxygen activation, Cu 0 Nanoparticles catalyze the breaking of C-Cl bonds, thereby reducing dioxin content; oxygen functional groups enhance surface affinity, optimize the compressive strength and porosity of building material substrates, and provide structural and performance guarantees for the application of environmentally friendly building materials.

[0156] As can be seen from Examples 1 to 4 and Table 1, the compressive strength of Examples 1-4 is 11.8-14.0 MPa, the dioxin content is as low as 0.05-0.09 ng-TEQ / kg, the heavy metal curing rate is as high as Pb 96.5-98.0%, Cd 97.2-98.5%, and the porosity is 10.5-12%.

[0157] Combining Example 1, Comparative Example 1, and Table 1, it can be seen that the building material substrate of Example 1 exhibits excellent performance: compressive strength of 12.5 MPa, dioxin content as low as 0.08 ng-TEQ / kg, heavy metal curing rate reaching Pb 96.5% and Cd 97.2%, and porosity of 12%. In contrast, the performance of Comparative Example 1 (without Fe-NC@Cu-NPs) is significantly reduced: compressive strength of only 8.5 MPa, dioxin content as high as 1.50 ng-TEQ / kg, heavy metal curing rate reduced to Pb 85.0% and Cd 87.0%, and porosity increased to 18.5%. This indicates that the Fe-NC@Cu-NPs modifier is crucial for improving substrate strength, reducing toxic pollutants, and optimizing microstructure. The excellent performance of the Fe-NC@Cu-NPs modifier stems from its unique chemical structure and synergistic catalytic mechanism. Nitrogen-doped carbon support (specific surface area 800-1200 m²) 2 / g, nitrogen content 8-12 wt%) provides abundant adsorption sites through CN bonds (286.2 eV) and pyridine nitrogen (398.5 eV), effectively capturing heavy metals (such as Pb, Cd) and dioxin molecules; Fe-N4 single-atom sites (711.0 / 724.5 eV) activate O2 through electronic effects, generating reactive oxygen species, catalyzing the oxidative cleavage of the aromatic ring of dioxins; Cu 0 Nanoparticles (932.6 / 952.4 eV) accelerate C-Cl bond breaking, promote dioxin dechlorination, and significantly reduce toxicity equivalent; oxygen functional groups (CO / C=O, 532.0 eV) enhance surface affinity and synergize with Fe-N4 and Cu. 0 Catalytic reaction of free CaO / MgO with SiO2 / Al2O3 to form stable silicates (such as CaSiO3) inhibits the formation of expansive products such as Ca(OH)2 / Mg(OH)2, thereby reducing porosity and increasing compressive strength.

[0158] Combining Example 1, Comparative Example 2, and Table 1, it can be seen that the building material substrate of Example 1 (containing 3 wt% Fe-NC@Cu-NPs, prepared by wet chemical method) exhibits excellent performance: compressive strength reaches 12.5 MPa, dioxin content is as low as 0.08 ng-TEQ / kg, heavy metal solidification rate is as high as Pb 96.5% and Cd 97.2%, and porosity is 12%. In contrast, the performance of Comparative Example 2 (a physical mixture of FeCl3 and CuCl2 replacing Fe-NC@Cu-NPs) is significantly reduced: compressive strength is only 9.0 MPa, dioxin content increases to 1.20 ng-TEQ / kg, heavy metal solidification rate decreases to Pb 88.0% and Cd 89.5%, and porosity increases to 17.0%. This indicates that the Fe-N4 single atoms and Cu nanoparticles prepared by wet chemical method are crucial to improving the substrate performance. The excellent performance of Fe-NC@Cu-NPs stems from its unique chemical structure and synergistic catalytic mechanism. Nitrogen-doped carbon support (specific surface area 800-1200 m²) 2 / g, nitrogen content 8-12wt%) provides high-density adsorption sites through CN bonds (286.2 eV) and pyridine nitrogen (398.5 eV), efficiently capturing heavy metals (such as Pb, Cd) and dioxins; Fe-N4 single-atom sites (711.0 / 724.5 eV) activate O2 through electronic effects to generate reactive oxygen species, catalyzing the oxidative cleavage of the dioxin aromatic ring (π-π transition, 290.5 eV); Cu 0 Nanoparticles (932.6 / 952.4 eV, 2-5 nm) were uniformly dispersed via a wet chemical method (NaBH4 reduction of CuCl2), catalyzing the breaking of C-Cl bonds to accelerate dechlorination and significantly reducing dioxin toxicity. Oxygen functional groups (CO / C=O, 532.0 eV) enhanced surface affinity, synergistically acting on Fe-N4 and Cu... 0 Catalyzing the reaction of CaO / MgO with SiO2 / Al2O3 to form stable silicates (such as CaSiO3) inhibits the formation of expansive Ca(OH)2 / Mg(OH)2, reduces porosity, and improves compressive strength. The physical mixture in Control Example 2 lacks Fe-N4 and Cu. 0 The nanoscale dispersion and nitrogen coordination lead to a decrease in catalytic efficiency and adsorption capacity, highlighting the necessity of wet chemical preparation.

[0159] Combining Example 1, Comparative Example 3, and the table, it can be seen that the building material substrate of Example 1 (containing 3 wt% Fe-NC@Cu-NPs, fly ash washed with water and heat-treated at 800℃) exhibits excellent performance: compressive strength reaches 12.5 MPa, dioxin content is as low as 0.08 ng-TEQ / kg, heavy metal solidification rate is as high as Pb 96.5% and Cd 97.2%, and porosity is 12%. In contrast, the performance of Comparative Example 3 (no fly ash heat treatment, only water washing) is significantly reduced: compressive strength is only 8.8 MPa, dioxin content increases to 0.80 ng-TEQ / kg, heavy metal solidification rate decreases to Pb 90.5% and Cd 91.2%, and porosity increases to 16.5%. This indicates that high-temperature heat treatment of fly ash (600-800℃) is crucial for removing organic pollutants and improving substrate performance.

[0160] Combining Example 1, Comparative Example 4, and the table, it can be seen that the building material substrate of Example 1 (containing 3 wt% Fe-NC@Cu-NPs, wet curing at 20℃ and 95% humidity for 15 days) exhibits excellent performance: compressive strength reaches 12.5 MPa, dioxin content is as low as 0.08 ng-TEQ / kg, heavy metal curing rate is as high as Pb 96.5% and Cd 97.2%, and porosity is 12%. In contrast, the performance of Comparative Example 4 (same formulation, but dry curing at room temperature at 25℃ and 50-60% humidity for 7 days) is significantly reduced: compressive strength is only 9.5 MPa, dioxin content increases to 0.15 ng-TEQ / kg, heavy metal curing rate decreases to Pb 92.0% and Cd 93.0%, and porosity increases to 20.0%. This indicates that wet curing conditions are crucial for the strength, toxicity control, and structural optimization of the substrate.

[0161] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A building material substrate produced from municipal solid waste incineration waste, characterized in that, The building material substrate is composed of the following components by weight percentage: Municipal solid waste incineration fly ash: 30-50 wt% Municipal solid waste incineration bottom ash: 20-40 wt% Silicate cement: 10-20 wt% Fe-NC@Cu-NPs: 3-10wt%; Water: 5-15 wt% The curing conditions for the building material substrate are: curing for 7-21 days at a temperature of 20-35℃ and a humidity of 80-95%; The fly ash from the municipal solid waste incineration undergoes pretreatment, including the following steps: More than 90% of soluble chloride salts in municipal solid waste incineration fly ash are removed by water washing, and organic pollutants are removed by heat treatment at 600-800℃ for 1-2 hours. The municipal solid waste incineration bottom ash is treated by screening and magnetic separation, with the particle size controlled between 0.25 mm and 5 mm and the iron content below 1 wt%. The preparation steps of the Fe-NC@Cu-NPs modifier include: using urea and glucose as precursors, with a mass ratio of urea to glucose of 2:1, pyrolyzing at 900℃ for 2 hours under a nitrogen atmosphere to prepare a nitrogen-doped carbon support with a specific surface area of ​​800-1200 m². 2 / g, nitrogen content is 8-12 wt%; Subsequently, the nitrogen-doped carbon support was dispersed in deionized water, and FeCl3 solution with Fe content of 0.5-2 wt% was added. The mixture was stirred at 80°C for 4 hours by wet chemical impregnation, and then heat-treated at 800°C under a nitrogen atmosphere for 1 hour to form Fe-N4 single-atom sites. Next, Fe-NC was dispersed in ethanol, CuCl2 solution was added with a Cu content of 1-5 wt%, and NaBH4 solution was added dropwise for reduction with a concentration of 0.1 mol / L. The reaction temperature was controlled at 25℃ and stirred for 2 hours to allow copper nanoparticles to be loaded in situ onto the support surface. Finally, the Fe-NC@Cu-NPs modifier was obtained by centrifugation and washing, including washing with deionized water and ethanol three times each, followed by vacuum drying at 60°C for 8 hours.

2. A preparation process for a building material substrate according to claim 1, characterized in that, Includes the following steps: Step S1: Pre-treat the fly ash and bottom ash from municipal solid waste incineration to obtain pre-treated fly ash and pre-treated bottom ash. Step S2: Preparation of the modifier Fe-NC@Cu-NPs: Nitrogen-doped carbon support was prepared by high-temperature pyrolysis, and single-atom iron and copper nanoparticles were loaded onto the support using a wet chemical method; Step S3: Mix the pretreated fly ash, pretreated bottom slag, silicate cement and modifier Fe-NC@Cu-NPs in proportion, add water and stir to form a homogeneous slurry; Step S4: Inject the slurry into the mold and use a vibration molding process with a molding pressure of 5-10 MPa; Step S5: Curing at a temperature of 20-35℃ and a humidity of 80-95% for 7-21 days yields the building material substrate.

3. The preparation process according to claim 2, characterized in that, In step S3, the mixing is carried out using a twin-shaft mixer at a speed of 100-200 rpm for 10-20 minutes.

4. The preparation process according to claim 2, characterized in that, In step S4, the vibration frequency of the vibration molding process is 30-50 Hz, and the vibration time is 1-3 minutes.

5. The preparation process according to claim 2, characterized in that, The dioxin content of the building material substrate is less than 0.1 ng-TEQ / kg.

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