Metal basic salt mineralized membrane, preparation method thereof and application of metal basic salt mineralized membrane as heterogeneous catalyst in organic wastewater treatment

Abstract

The invention belongs to the technical field of treatment of wastewater containing heavy metal ions and refractory organic wastewater, and particularly relates to a metal basic salt mineralized membrane, a preparation method thereof and application of the metal basic salt mineralized membrane as a heterogeneous catalyst in treatment of organic wastewater. The method comprises the following steps: mixing composite particles with heavy metal wastewater, carrying out hydration reaction under a standing condition to obtain particles with metal basic salt mineralized membranes on the outer layers, and separating to obtain the metal basic salt mineralized membranes. The metal basic salt mineralized membrane provided by the invention can be combined with hydrogen peroxide (or visible light or both hydrogen peroxide and visible light) as a heterogeneous catalyst to exert Fenton-like catalysis, photocatalysis or photo-Fenton catalysis efficiency to treat refractory organic wastewater, and the catalytic efficiency is excellent and stable when the metal basic salt mineralized membrane is recycled for multiple times.

Description

Technical Field

[0001] This invention belongs to the field of treatment technology for wastewater containing heavy metal ions and recalcitrant organic wastewater, specifically relating to a metal basic salt mineralization membrane and its preparation method, as well as its application as a heterogeneous catalyst in the treatment of organic wastewater. Background Technology

[0002] Water environment management faces two major challenges: heavy metal pollution and persistent organic pollutants (POPs). The dual control and resource utilization of these two pollutants have become key scientific issues urgently needing to be addressed in the field of environmental engineering.

[0003] Advanced oxidation processes (AOPs) have been repeatedly reported to be highly efficient at degrading pollutants. In recent years, among various AOPs, the application of Fenton-like and photo-Fenton technologies to degrade organic dyes and antibiotics has attracted scientific attention. While Fenton-like and photo-Fenton technologies are highly efficient means of degrading organic dyes and antibiotics, their core technological bottleneck lies in the high Fe ion dissolution rate, poor cycle stability, and Fe sludge formation associated with homogeneous catalysts. Although heterogeneous catalysts can overcome these shortcomings, nanoscale heterogeneous catalysts suffer from easy aggregation and difficulty in recycling. Furthermore, existing non-nanoscale supports are mostly artificially synthesized materials such as MOFs and graphene, resulting in high preparation costs and insufficient environmental compatibility. Therefore, there is an urgent need to develop a novel, economically feasible, highly efficient, stable, easily recyclable, and reusable heterogeneous Fenton / visible Fenton green catalyst.

[0004] For heavy metal ion wastewater, existing treatment technologies, such as chemical precipitation and adsorption, can achieve preliminary removal of heavy metals, but they have limitations such as low added value of the products, large amounts of precipitated sludge (hazardous waste), difficulty in separating sludge and water, small adsorbent capacity, and easy generation of secondary pollution. While membrane separation and electrochemical reduction technologies can improve recovery efficiency, they face bottlenecks such as high equipment investment and high operating energy consumption. In particular, the valuable metals in the wastewater are precious mineral resources that have not been effectively recovered and utilized. Traditional heavy metal treatment technologies mostly focus on the efficient removal of heavy metals and metalloids, but generally neglect the potential for metal resource recovery and high-value utilization. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a metal basic salt mineralization membrane and its preparation method, as well as its application as a heterogeneous catalyst in the treatment of organic wastewater. The metal basic salt mineralization membrane prepared by this invention using heavy metal wastewater can be used as a heterogeneous catalyst in combination with hydrogen peroxide (or visible light irradiation or simultaneous hydrogen peroxide + visible light irradiation) to exert Fenton-like catalytic, photocatalytic, or photo-Fenton catalytic effects to treat recalcitrant organic wastewater. Moreover, it has excellent and stable catalytic performance after multiple cycles, which is beneficial to the recovery and high-value utilization of metal resources.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a metal basic salt mineralization film, comprising the following steps: The composite particles and heavy metal wastewater are mixed and subjected to a hydration reaction under static conditions. The resulting colloidal liquid membrane adsorbs, precipitates, and crystallizes the heavy metal ions in the heavy metal wastewater to obtain particles with an outer metal basic salt mineralization membrane. There is a gap between the metal basic salt mineralization membrane and the particles in the particles with the outer metal basic salt mineralization membrane. The particles with the outer layer of metal basic salt mineralization film are separated to obtain the metal basic salt mineralization film and particles, which are then recycled separately. The method for preparing the composite particles includes the following steps: Sodium carbonate, bentonite, carbide slag and water are mixed and then granulated and dehydrated in sequence to obtain composite particles.

[0007] Preferably, the heavy metal ions in the heavy metal wastewater include Cu. 2+ Fe 2+ Zn 2+ Mn 2+ Co 2+ and Ni 2+ One or more of the following; the concentration of heavy metal ions in the heavy metal wastewater is 150~1000 mg / L, and the pH value is 3.0~6.5.

[0008] Preferably, the ratio of the composite particles to the heavy metal wastewater is (0.1~3.5)g:(0.1~1)L.

[0009] The present invention also provides a metal basic salt mineralization film prepared by the preparation method described in the above technical solution, the main component of which is metal basic salt crystal.

[0010] The present invention also provides the application of the metal basic salt mineralization membrane described above as a heterogeneous catalyst in the treatment of organic wastewater.

[0011] Preferably, the organic wastewater contains at least one of organic dyes and antibiotics; the organic dyes include one or more of Congo red, methylene blue, rhodamine b, and methyl orange; the antibiotics include one or more of norfloxacin, enoxacin, levofloxacin, and sulfadiazine; the concentration of the organic dyes in the organic wastewater is 20-200 mg / L, and the concentration of the antibiotics is 5-50 mg / L.

[0012] Preferably, the method for treating organic wastewater includes Fenton-like process, photocatalysis, or photo-Fenton process.

[0013] Preferably, the photocatalytic method involves adding a metal basic salt mineralization membrane to organic wastewater and carrying out a photocatalytic reaction under visible light irradiation.

[0014] Preferably, the steps of the Fenton-like method are as follows: adding a metal basic salt mineralization membrane and hydrogen peroxide to organic wastewater, adjusting the pH of the system to 3.0~9.5, and then carrying out a Fenton-like catalytic reaction.

[0015] Preferably, the steps of the photo-Fenton method are as follows: adding a metal basic salt mineralization film and hydrogen peroxide to organic wastewater, and carrying out a photo-Fenton catalytic reaction under visible light irradiation.

[0016] This invention provides a method for preparing a metal basic salt mineralization film, comprising the following steps: The composite particles and heavy metal wastewater are mixed and subjected to a hydration reaction under static conditions. The resulting colloidal liquid membrane adsorbs, precipitates, and crystallizes the heavy metal ions in the heavy metal wastewater to obtain particles with an outer metal basic salt mineralization membrane. There is a gap between the metal basic salt mineralization membrane and the particles in the particles with the outer metal basic salt mineralization membrane. The particles with the outer layer of metal basic salt mineralization film are separated to obtain the metal basic salt mineralization film and particles, which are then recycled separately. The method for preparing the composite particles includes the following steps: Sodium carbonate, bentonite, carbide slag and water are mixed and then granulated and calcined in sequence to obtain composite particles.

[0017] Beneficial effects: This invention utilizes composite particles to recover heavy metal ions from heavy metal wastewater and prepare a heterogeneous metal basic salt mineralization membrane, which is rich in numerous metal-based active sites and surface hydroxyl groups (OH). - When used in conjunction with hydrogen peroxide (or visible light irradiation, or both), this membrane exhibits Fenton-like, photocatalytic, or photo-Fenton-like catalytic efficacy in treating recalcitrant organic wastewater. It demonstrates excellent and stable catalytic performance with multiple cycles, achieving the dual benefits of heavy metal resource recovery and organic pollution control. Furthermore, this metal basic salt mineralization membrane is low-cost, simple to prepare and use, economically feasible, highly efficient and stable, produces no Fenton sludge, is environmentally friendly, easy to recycle, and can be reused multiple times, providing a viable pathway for heavy metal resource recovery and efficient organic degradation. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the process flow for the recovery and preparation of composite particles and metal basic salt mineralization membranes in this invention, wherein (a) is the preparation of composite particles, (b) is the experimental apparatus used for mineralization membrane preparation, (c) is the film formation stage of mineralization membrane, (d) is the self-growth stage of mineralization membrane, (e) is the maturation stage of mineralization membrane, (f) is the separation and extraction of mineralization membrane, (g) is the recovery of composite particles, (h) is the natural drying of mineralization membrane, and (i) is the recovered metal basic salt mineralization membrane; Figure 2 A macroscopic photograph of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention; Figure 3 This is a flowchart illustrating the preparation process of the metal basic salt mineralization film recovered and obtained in Example 1 of the present invention. Figure 4 This is a diagram illustrating the growth process of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention. Figure 5 This is a schematic diagram illustrating the photocatalytic principle of Congo Red CR using the metal basic salt mineralization membrane recovered and prepared in Example 1 of the present invention. Figure 6 The figures shown in Example 1 of this invention illustrate the photocatalytic effect of the metal basic salt mineralization membrane recovered and prepared on Congo red CR. (a) shows the photocatalytic performance of Cu-MF on CR and the concentration of H2O2 produced; (b) shows the quenching results of Cu-MF on the photocatalytic active groups of CR; and (c) shows the effect of Cu-MF on the photocatalytic degradation of CR after 5 cycles and the Cu-MF concentration after each cycle. 2+ Leaching concentration graph; Figure 7 This is a SEM image showing the microstructure of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention. Figure 8 This is an EDS image showing the microstructure of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention. Figure 9 This is a diagram showing the elemental composition of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention. Figure 10 The image shows the microscopic characterization XRD pattern of the metal basic salt mineralization film recovered and prepared in Example 1 of this invention. Figure 11 A macroscopic photograph of the metal basic salt mineralization film recovered and prepared in Example 2 of the present invention; Figure 12 The diagram above shows the process flow of the metal basic salt mineralization membrane recovered and prepared in Example 2 of the present invention and the schematic diagram of its CR-type Fenton catalytic principle for Congo red (bottom). Figure 13 The graph shows the effect of the metal basic salt mineralization membrane recovered and prepared in Example 2 of this invention on Congo red CR-type Fenton catalysis. Figure 14The diagram shows the effect of multiple recycling of the metal basic salt mineralization membrane recovered and prepared in Example 2 of the present invention, where (a) is 1 to 8 times, (b) is 9 to 16 times, (c) is 17 to 24 times, and (d) is 25 to 32 times. Figure 15 The images shown are SEM images of the metal basic salt mineralization film recovered and prepared in Example 2 of the present invention, where (a) is SEM 3000 and (b) is SEM 10000. Figure 16 The image shows the EDS of the metal basic salt mineralization film recovered and prepared in Example 2 of the present invention, where (c) is the EDS and (d) is the percentage of each element. Figure 17 The above are XRD patterns of the metal basic salt mineralization film recovered and prepared in Example 2 of the present invention before use and after 32 cycles of use. Figure 18 A macroscopic photograph of the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention; Figure 19 This is a schematic diagram of the preparation process of the composite particles (a) and the recycled metal basic salt mineralization film (b) in Example 3 of the present invention; Figure 20 This is a magnified SEM image of the flower-like nanosphere crystals of the metal basic salt mineralization film in Example 3 of the present invention. Figure 21 This is a schematic diagram illustrating the photocatalytic principle of norfloxacin using the metal basic salt mineralization membrane recovered and prepared in Example 3 of the present invention. Figure 22 The image shows the effect of the metal basic salt mineralization membrane recovered and prepared in Example 3 of this invention on the photocatalytic Fenton effect of norfloxacin. Figure 23 The images shown are SEM and EDS images of the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention, where (ac) is the SEM before the reaction, (df) is the SEM after the reaction, (gj) is the EDS before the reaction, and (kn) is the EDS after the reaction. Figure 24 This is a diagram showing the proportion of each element in the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention; Figure 25 This is a particle size analysis diagram of the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention, where (p) is the particle size analysis before the reaction and (q) is the particle size analysis after the reaction. Figure 26 The graph shows the changes in BET specific surface area (a) and pore size (b) of the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention before and after the reaction. Figure 27The diagram shows the degradation and removal effect of norfloxacin in Comparative Example 1 of this invention. Fe(OH)3 is a commercially available Fe(OH)3 reagent, Fe-MF is a self-grown Fe mineralization film without ascorbic acid, and AA-Fe-MF is a self-grown mineralization film with ascorbic acid. Detailed Implementation

[0019] This invention provides a method for preparing a metal basic salt mineralization film, comprising the following steps: The composite particles and heavy metal wastewater are mixed and subjected to a hydration reaction under static conditions. The resulting colloidal liquid membrane adsorbs, precipitates, and crystallizes the heavy metal ions in the heavy metal wastewater to obtain particles with an outer metal basic salt mineralization membrane. There is a gap between the metal basic salt mineralization membrane and the particles in the particles with the outer metal basic salt mineralization membrane. The particles with the outer layer of metal basic salt mineralization film are separated to obtain the metal basic salt mineralization film and particles, which are then recycled separately. The method for preparing the composite particles includes the following steps: Sodium carbonate, bentonite, carbide slag and water are mixed and then granulated and dehydrated in sequence to obtain composite particles.

[0020] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0021] As one embodiment, the heavy metal ions in the heavy metal wastewater include Cu. 2+ Fe 2+ Zn 2+ Mn 2+ Co 2 + and Ni 2+ One or more of the following, specifically Cu in the embodiment. 2+ , or Cu 2+ and Fe 2+ , or Fe 2+ The concentration of heavy metal ions in the heavy metal wastewater is 150~1000 mg / L, specifically 150~300 mg / L in this embodiment, and the pH value is 3.0~6.5, specifically 3.6 or 5.0 in this embodiment; the anions in the heavy metal wastewater include SO42-. 2- The ratio of the composite particles to the heavy metal wastewater is (0.1~3.5) g:(0.1~1) L, specifically 0.4 g:200 mL or 2 g:1 L in this embodiment. When the pH value of the heavy metal wastewater is not within the range of 3.0~6.5, the pH value of the heavy metal wastewater is adjusted to 3.0~6.5 with an acid solution; the acid solution is a sulfuric acid solution; the concentration of the sulfuric acid solution is 0.1 M.

[0022] As one implementation method, when the heavy metal wastewater contains only Fe 2+ When adding ascorbic acid to the heavy metal wastewater, the concentration of ascorbic acid in the heavy metal wastewater is 100~500mg / L, and in a specific embodiment it is 200mg / L.

[0023] For heavy metal wastewater containing Fe(II), Fe(II) is easily oxidized and forms precipitates during the film-forming mineralization process, making it difficult to recover a complete mineralized film. To obtain a more ideal mineralized film, this invention innovatively proposes adding ascorbic acid (AA) to the heavy metal wastewater for regulation. Ascorbic acid has multiple hydroxyl groups (OH). - The structure allows it to coordinate with heavy metal Fe(II) in wastewater, which not only makes Fe(II) more dispersed and uniformly self-grown into a film at multiple sites, but also inhibits the rapid oxidation of low-valence metal Fe(II) to form a precipitate. This results in the mineralization film containing multivalent metals Fe(II) and Fe(III), which makes the mineralization film have a better catalytic effect.

[0024] In one implementation, the hydration reaction temperature is 10~35℃, specifically 25℃ in this embodiment, and the time is 24~48h, specifically 48h in this embodiment; after the hydration reaction, the process further includes: ripening; the ripening temperature is 10~35℃, specifically 25℃ in this embodiment, and the time is 0~48h, specifically 24h in this embodiment.

[0025] In one embodiment, after the hydration reaction, the process further includes: naturally drying the mineralized film produced by the hydration reaction and then recovering it. The present invention does not specifically limit the natural drying process; any process well-known in the art can be used.

[0026] As one embodiment, the method for preparing the composite particles includes the following steps: Sodium carbonate, bentonite, carbide slag and water are mixed and then granulated and dehydrated in sequence to obtain composite particles.

[0027] In one embodiment, the particle size of the bentonite and carbide slag is independently ≤74μm; the mass ratio of the bentonite and carbide slag is 40~20:60~80, and in a specific embodiment it is 2:8 (i.e. 20:80); the mass of the sodium carbonate accounts for 1~20% of the total mass of the sodium carbonate, bentonite and carbide slag, in another embodiment it is 5~15%, and in a specific embodiment it is 10%.

[0028] In one embodiment, the chemical composition of the bentonite, by mass percentage, includes: SiO2: 65-80%, Al2O3: 11-17%, Na2O: 3.0-6.0%, CaO: 2.0-3.5%, MgO: 2.0-5.0%, Fe2O3: 1.6-4.0%, TiO2: 0.04-0.20%, K2O: 0.1-1.2%, and impurities: 0.10-2.16%; the chemical composition of the carbide slag, by mass percentage, includes: CaO: 86.7-94.5%, SiO2: 2.0-6.5%, Al2O3: 0.5-3.0%, Na2O: 0.5-2.5%, Fe2O3: 0.2-1.5%, MgO: 0.10-0.22%, TiO2: 0.01-0.08%, and impurities: 1.0-1.72%.

[0029] In a specific embodiment of the present invention, the chemical composition of the bentonite includes: SiO2: 71.33%, Al2O3: 14.55%, Na2O: 4.26%, CaO: 3.23%, MgO: 3.59%, Fe2O3: 2.27%, TiO2: 0.11%, K2O: 0.51%, and impurities: 0.15%; the chemical composition of the carbide slag includes: CaO: 92.65%, SiO2: 3.95%, Al2O3: 0.84%, Na2O: 0.73%, Fe2O3: 0.20%, MgO: 0.15%, TiO2: 0.07%, and impurities: 1.41%.

[0030] In one embodiment, the mixing of sodium carbonate, bentonite, carbide slag and water involves first mixing the sodium carbonate, bentonite and carbide slag evenly, and then adding water for a second mixing; the mass ratio of the total mass of sodium carbonate, bentonite and carbide slag to the mass of water is 1:0.5~0.9, and in a specific embodiment it is 1:0.7.

[0031] In one embodiment, the granulation involves kneading a mixture of sodium carbonate, bentonite, carbide slag, and water until it reaches a plastic state, extruding it into strips, dividing it into granules, and drying it. The diameter of the strips is 2-3 mm, specifically 2 mm or 2.5 mm in this embodiment. The extrusion equipment is an extruder, specifically a small manual noodle press in this embodiment. The particle size of the granulated material is 2-7 mm, specifically 2-5 mm in this embodiment. The drying process involves air drying in a dark place for 1-3 hours, specifically 60 minutes in this embodiment.

[0032] In one implementation, the dehydration condensation is carried out by drying or calcination under natural conditions, specifically calcination in this embodiment; the drying time is 24~48h, specifically 48h in this embodiment; the calcination temperature is 100~300℃, specifically 150℃ in this embodiment, and the time is 0.6~1.5h, specifically 1h in this embodiment.

[0033] As one implementation method, before roasting, the granulated material is aged; the aging temperature is 10~35℃, specifically 25℃ in this embodiment, and the time is 1~12h, specifically 1h or 3h in this embodiment; the aging is carried out naturally in a dark and ventilated place.

[0034] In one embodiment, the apparatus used to prepare the metal basic salt mineralization film includes a transparent plastic box and a perforated plate placed inside the transparent plastic box; the transparent plastic box has dimensions of 110mm × 80mm × 80mm; the perforated plate has dimensions of 105mm in length × 75mm in width, a hole diameter of 6mm, and a hole spacing of 16mm.

[0035] In one embodiment, the present invention uses the metal basic salt mineralization membrane as a heterogeneous metal basic salt mineralization membrane catalyst for recovery.

[0036] Figure 1 This is a schematic diagram of the process flow for the recovery and production of composite particles and metal basic salt mineralization films in this invention. Figure 1 It is known that the present invention utilizes bentonite-carbide slag composite particles to achieve high-purity mineralization and recovery of valuable metals in heavy metal wastewater. The mineralized film formed in situ is recovered as a metal-based film material - mineralized film. This mineralized film also contains metal elements such as M, O, and S, and has a stable film structure. It can overcome the problems of easy agglomeration and difficulty in recovery of nanomaterials, as well as the high cost of preparation of artificial synthetic materials such as MOFs and graphene. It can be used as a low-cost heterogeneous stable catalyst for the degradation of organic pollutants.

[0037] This invention addresses the challenges of treating heavy metal wastewater due to its high toxicity, difficulty in treatment, high cost, and the difficulty in recovering valuable metals, as well as the recalcitrant degradation of organic dye and antibiotic wastewater. It utilizes bentonite-carbide slag composite particles to treat heavy metal wastewater, enabling the spontaneous formation and growth of a metal basic salt mineralization film. The main component of this mineralization film is metal basic salt crystals (such as Cu4SO4(OH)6, etc.), with copper ions reacting with OH- released from the composite particles. - and SO4 in heavy metal wastewater 2- (Reaction generated), rich in highly active metal groups and surface OH groups - It can be recycled and used as a heterogeneous Fenton, visible light catalysis, and visible light Fenton catalyst to treat recalcitrant organic wastewater.

[0038] The present invention also provides a metal basic salt mineralization film prepared by the preparation method described in the above technical solution, the main component of which is metal basic salt crystal.

[0039] In one embodiment, the basic metal salt crystallizes into Cu4SO4(OH)6.

[0040] Metal basic salt crystals (such as Cu4SO4(OH)6) are rich in highly active metal groups and surface OH groups. - It can be recycled and used as a heterogeneous Fenton, visible light catalysis, and visible light Fenton catalyst to treat recalcitrant organic wastewater.

[0041] The present invention also provides the application of the metal basic salt mineralization membrane described above as a heterogeneous catalyst in the treatment of organic wastewater.

[0042] In one embodiment, the organic wastewater contains at least one of organic dyes and antibiotics, specifically an organic dye; the organic dye includes one or more of Congo red, methylene blue, rhodamine b, and methyl orange, specifically Congo red (CR); the antibiotic includes one or more of norfloxacin, enoxacin, levofloxacin, and sulfadiazine, specifically norfloxacin (NOR); the concentration of the organic dye in the organic wastewater is 20-200 mg / L, specifically 50 mg / L in this embodiment, and the concentration of the antibiotic is 5-50 mg / L, specifically 10 mg / L in this embodiment; the pH value of the organic wastewater is 3.0-9.5, specifically 5.0 in this embodiment. When the pH value of the organic wastewater is not within the range of 3.0-9.5, the pH value of the organic wastewater is adjusted to 3.0-9.5; the reagent used to adjust the pH value of the organic wastewater is a 0.10M NaOH solution or a 0.10M H2SO4 solution.

[0043] As one implementation method, the method for treating organic wastewater includes Fenton-like process, photocatalysis, or photo-Fenton process.

[0044] As one implementation method, the photocatalytic method comprises the following steps: adding a metal basic salt mineralization membrane to organic wastewater and carrying out a photocatalytic reaction under visible light irradiation; the concentration of the metal basic salt mineralization membrane in the organic wastewater is 0.5~2.5 g / L, specifically 0.7 g / L in this embodiment; the visible light irradiation is provided by a xenon lamp; the power of the xenon lamp is 150~550W, specifically 300W in this embodiment; and the intensity of the visible light irradiation is 200~2000 mW / cm². 2 In a specific embodiment, it is 800mW / cm 2The visible light irradiation time is 60~180min, and in a specific embodiment it is 180min; the photocatalytic reaction is carried out under stirring conditions; the stirring speed is 100~700r / min, and in a specific embodiment it is 500r / min.

[0045] In one embodiment, the steps of the Fenton-like method are as follows: A metal basic salt mineralization membrane and hydrogen peroxide are added to organic wastewater, and the pH of the system is adjusted to 3.0-9.5 before a Fenton-like catalytic reaction is carried out. The mass fraction of the hydrogen peroxide is 30%. The concentration of the metal basic salt mineralization membrane in the organic wastewater is 0.5-2.5 g / L, specifically 1.4 g / L in this embodiment, and the concentration of hydrogen peroxide is 0.5-3.0 mmol / L, specifically 1.8 mmol / L in this embodiment. The pH of the system is adjusted to 3.0-9.5, specifically 6.68 in this embodiment. The temperature of the Fenton-like catalytic reaction is 10-45℃, specifically 25℃ in this embodiment, and the time is 1.0-3 h, specifically 2 h in this embodiment. The Fenton-like catalytic reaction is carried out in a shaker. The rotation speed of the shaker is 50-300 r / min, specifically 100 r / min in this embodiment.

[0046] In one embodiment, the photo-Fenton method comprises the following steps: adding a metal basic salt mineralization membrane and hydrogen peroxide to organic wastewater, and conducting a photo-Fenton catalytic reaction under visible light irradiation; the concentration of the metal basic salt mineralization membrane in the organic wastewater is 0.1~2.5 g / L, specifically 0.5 g / L in this embodiment; the concentration of hydrogen peroxide in the organic wastewater is 0.1~3.5 mmol / L, specifically 1.8 mmol / L or 3.0 mmol / L in this embodiment; the visible light irradiation is provided by a xenon lamp; the power of the xenon lamp is 150~550W, specifically 300W in this embodiment; and the intensity of the visible light irradiation is 200~2000 mW / cm². 2 In a specific embodiment, it is 800mW / cm 2 The duration of visible light illumination is 30-120 minutes, and in a specific embodiment it is 60 minutes.

[0047] As one implementation method, after the organic wastewater treatment is completed, the method further includes recycling the metal basic salt mineralization membrane for reuse; the number of times the membrane is recycled is 5 to 32 times, and in specific embodiments it is 5 times and 32 times.

[0048] The metal basic salt mineralization membrane catalyst provided by this invention exhibits excellent and stable catalytic efficiency for decolorizing and degrading organic dyes and antibiotics after multiple cycles, with a low metal leaching rate. It is a low-cost, simple-to-prepare and-use catalyst with excellent and stable performance, no Fenton sludge, and is environmentally friendly.

[0049] This invention first prepares composite particles by controlling the ratio of bentonite and carbide slag, especially the amount of sodium carbonate added. Then, by controlling the amount of composite particles added, the type and concentration of heavy metal wastewater, pH value, temperature, self-growth time, and especially the amount of ascorbic acid added, it effectively recovers heavy metal ions and produces a product rich in metal-based active sites and surface hydroxyl groups (OH). - This invention provides a metal basic salt mineralization membrane catalyst, and by adjusting the dosage of the catalyst and hydrogen peroxide (or visible light intensity, or simultaneously adjusting the hydrogen peroxide dosage and visible light intensity), it achieves Fenton-like, photocatalytic, or photo-Fenton-like effects to treat recalcitrant organic wastewater. Experimental results show that the heterogeneous metal basic salt mineralization membrane provided by this invention has high mineral phase purity, large specific surface area, a metal mass percentage exceeding 47.99%, and is rich in metal active sites and surface hydroxyl groups (OH). - When used in combination with hydrogen peroxide (or visible light irradiation, or both hydrogen peroxide and visible light irradiation), it can exert Fenton-like catalytic, photocatalytic, and photo-Fenton catalytic effects, producing large amounts of •OH and •O. 2- , 1 Active oxygen species such as O2 achieve decolorization and degradation removal rates of over 92% for organic dyes and antibiotics. Even after more than five cycles of use, their efficiency remains excellent and stable, with metal ion leaching rates consistently below 5.0 mg / L. Furthermore, the method consumes minimal amounts of hydrogen peroxide, significantly reducing reagent costs. This method achieves the dual benefits of heavy metal resource recovery and organic pollution control. Moreover, the catalyst is low-cost, simple to prepare and use, exhibits excellent and stable performance, produces no Fenton sludge, and is environmentally friendly, providing a feasible pathway for heavy metal resource recovery and efficient organic pollution degradation.

[0050] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments thereof, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1 (1) Preparation of composite particles: The main components of the composite particles are bentonite (particle size ≤74μm) and carbide slag (particle size ≤74μm). After drying, the two are mixed in a mass ratio of 2:8. At the same time, 10% of anhydrous Na2CO3 is added as a binder and activator. After adding deionized water and stirring, cylindrical particles with a length and diameter of 2mm are formed. They are then placed in a dark place and air-dried naturally for 60 minutes. The mass ratio of sodium carbonate, bentonite and carbide slag to water is 1:0.7. Finally, the particles are calcined in a muffle furnace at 150℃ for 1 hour to produce the finished particles. (2) Composite particle treatment for heavy metal wastewater recovery and mineralization membrane: The experimental setup consisted of a self-made transparent plastic square box, used in conjunction with a multi-well plate. During the experiment, the prepared composite particles were evenly distributed in the small holes of the multi-well plate, and 200 mL of acidic water sample containing heavy metal ions (containing SO42-) was injected into the square box.2- In acidic water samples containing heavy metal ions, heavy metal ions spontaneously form and grow a mineralized film around them under the action of the composite particle hydration reaction. After the film formation and self-growth process, the porous plate is removed, and the spherical sheet-like mineralized film is separated and naturally dried to obtain the mineralized film (Cu-MF). The conditions for 200 mL of acidic water samples containing heavy metal ions are set as follows: Cu 2+ The concentration was 300 mg / L; pH = 3.6; the reaction temperature was room temperature (25℃); the particle dosage was 0.4 g / 200 mL; the reaction time was 48 h; and the reaction was then cured at 25℃ for 24 h. The chemical composition of bentonite, by mass percentage, includes: SiO2: 71.33%, Al2O3: 14.55%, Na2O: 4.26%, CaO: 3.23%, MgO: 3.59%, Fe2O3: 2.27%, TiO2: 0.11%, K2O: 0.51%, and impurities: 0.15%. The chemical composition of carbide slag, by mass percentage, includes: CaO: 92.65%, SiO2: 3.95%, Al2O3: 0.84%, Na2O: 0.73%, Fe2O3: 0.20%, MgO: 0.15%, TiO2: 0.07%, and impurities: 1.41%.

[0052] Example 2 (1) Preparation of composite particles: The composite particles are made of carbide slag (particle size ≤74μm) and bentonite (particle size ≤74μm) as raw materials, and anhydrous sodium carbonate as binder and activator. The preparation conditions are: the mass ratio of carbide slag to bentonite is 8:2, the amount of anhydrous sodium carbonate added is 10% of the total mass of raw materials, the calcination temperature is 150℃, and the calcination time is 60min. The specific preparation process is as follows: the dried and cooled carbide slag, bentonite and anhydrous sodium carbonate are mixed evenly in the above ratio, deionized water is added (the mass ratio of the total mass of sodium carbonate, bentonite and carbide slag to water is 1:0.7) and kneaded until plastic. After being extruded into strips with a diameter of 2mm by an extruder, they are divided into particles with a length of about 2mm. They are placed in a dark and ventilated place for natural aging for 2h, and then placed in a muffle furnace to complete the calcination. After cooling, they are sealed for later use. (2) Preparation of mineralized membrane: The mineralized membrane was prepared in a square box with dimensions of 110mm×80mm×80mm. A porous plate with dimensions of 105mm×75mm, a pore diameter of 6mm, and a pore spacing of 16mm was placed inside the box. 200mL of acidic heavy metal ion wastewater (300mg / L Cu) was injected into the square box. 2+ +150mg / L Fe 2+ Coexisting mixed water samples containing SO4 2- The water sample had a pH of 3.6. 0.4 g of the prepared composite particles were uniformly distributed in the pores of a porous plate. The Cu in the acidic wastewater was measured at 25°C.2+ Fe 2+ Under the action of the composite particle hydration reaction, a mineralized film is spontaneously formed and grown around it. After 3 days of film formation, self-growth and ripening process, the porous plate is taken out and the spherical sheet mineralized film is separated. After natural drying, Cu-Fe bimetallic mineralized film (Cu@Fe-MF) is obtained. The chemical composition of bentonite, by mass percentage, includes: SiO2: 71.33%, Al2O3: 14.55%, Na2O: 4.26%, CaO: 3.23%, MgO: 3.59%, Fe2O3: 2.27%, TiO2: 0.11%, K2O: 0.51%, and impurities: 0.15%. The chemical composition of carbide slag, by mass percentage, includes: CaO: 92.65%, SiO2: 3.95%, Al2O3: 0.84%, Na2O: 0.73%, Fe2O3: 0.20%, MgO: 0.15%, TiO2: 0.07%, and impurities: 1.41%.

[0053] Example 3 The calcium carbide slag and bentonite were crushed and ground, and passed through a 200-mesh sieve. The two materials, along with Na2CO3, were placed in a 105°C forced-air drying oven and dried for 120 minutes. The calcium carbide slag and bentonite were mixed at a mass ratio of 8:2, and 10% of the total mass of Na2CO3 admixture was added. Deionized water was added (the mass ratio of the total mass of sodium carbonate, bentonite, and calcium carbide slag to water was 1:0.7). After mixing evenly, the composite material was extruded into strips with a diameter of 2.5 mm using a small manual dough press. Then, it was cut into uniformly sized composite particles using a blade. The composite particles were aged in a dark and ventilated place for 1 hour, and then placed in a muffle furnace and calcined at 150°C for 60 minutes. After cooling, they were ready for use. The composite particles (2 g / L) were placed in a self-developed reactor, and simulated heavy metal acidic wastewater (prepared with FeSO4) and ascorbic acid (AA) were added. 2+ With Fe and AA concentrations of 300 mg / L and 200 mg / L respectively, and pH adjusted to 5.0 with 0.1 M H2SO4, the mixture was left to stand at 25℃ for 24 h. The heavy metal Fe ions underwent in-situ mineralization and self-growth to form a mineralized film Fe@AA-MF, which was then extracted, dried, and recovered. The chemical composition of bentonite, by mass percentage, includes: SiO2: 71.33%, Al2O3: 14.55%, Na2O: 4.26%, CaO: 3.23%, MgO: 3.59%, Fe2O3: 2.27%, TiO2: 0.11%, K2O: 0.51%, and impurities: 0.15%. The chemical composition of carbide slag, by mass percentage, includes: CaO: 92.65%, SiO2: 3.95%, Al2O3: 0.84%, Na2O: 0.73%, Fe2O3: 0.20%, MgO: 0.15%, TiO2: 0.07%, and impurities: 1.41%.

[0054] Application Example 1 Experiment on the photocatalytic decolorization and degradation performance of Cu-MF on Congo red (CR): 100 mL of CR solution with a concentration of 50 mg / L and 0.07 g of Cu-MF were added sequentially to a 150 mL flask. The flask was then placed under a 300 W xenon lamp with a 420 nm cutoff filter for visible light irradiation at an intensity of 800 mW / cm². 2 The magnetic stirring speed was 500 r / min, the reaction time was 3 h, and samples were taken every 30 min during the reaction.

[0055] Application Example 2 The decolorization and degradation effect and the catalytic performance of the catalyst were characterized by the concentration of CR solution. The specific process and initial conditions are as follows: 50 mL of CR solution with a concentration of 50 mg / L, 0.07 g of Cu@Fe-MF, and 0.01 mL of 30% hydrogen peroxide (H2O2) with a mass fraction of 1.8 mmol / L were added sequentially to a 100 mL Erlenmeyer flask. After adjusting the pH of the system to 6.68, the Erlenmeyer flask was placed in a shaker and the Fenton-like catalytic decolorization and degradation reaction was carried out at a speed of 100 r / min and a temperature of 25 °C for 2 h. Samples were taken at regular intervals during the reaction.

[0056] Application Example 3 Add 50 mg of Fe@AA-MF catalyst to 100 mL of norfloxacin (NOR) solution with pH 5.00 and a concentration of 10 mg / L; irradiate with a 300 W xenon lamp with a 420 nm cutoff filter (visible light intensity 800 mW / cm²). 2 Simultaneously, 30.60 μL of 30% H2O2 solution (hydrogen peroxide concentration of 3.0 mmol / L) was added to carry out the photo-Fenton catalytic reaction for 60 min. The pH of the NOR solution was adjusted with diluted NaOH (0.10 M) or H2SO4 (0.10 M).

[0057] Comparative Example 1 The degradation and removal effects of norfloxacin were compared using commercially available Fe(OH)3 reagent, a self-grown Fe mineralization membrane without ascorbic acid (Fe-MF, preparation steps were the same as in Example 3, except ascorbic acid was not added), and a self-grown mineralization membrane AA-Fe-MF with ascorbic acid (preparation steps were the same as in Example 3). See [link to relevant documentation]. Figure 27 .

[0058] The degradation and removal conditions for norfloxacin were exactly the same as in Application Example 3 (i.e., the pH of the norfloxacin water sample was 5.00, the concentration was 10 mg / L, the temperature was 25°C, the catalyst dosage was 0.5 g / L, the hydrogen peroxide concentration was 3.0 mmol / L, the xenon lamp power was 300 W, and the light intensity was 800 Wm / cm²). 2 The illumination time is 60 minutes.

[0059] Performance testing Figure 2 This is a macroscopic photograph of the metal basic salt mineralization membrane recovered and prepared in Example 1 of the present invention. As can be seen from the figure, the mineralization membrane has a stable membrane structure, which can overcome the problem of easy agglomeration and difficulty in recycling of nanomaterials. It can be used as a low-cost heterogeneous stable catalyst, which is easy to separate solid and liquid, easy to recycle, and can be used multiple times.

[0060] Figure 3 The flowchart of the preparation process of the metal basic salt mineralization membrane recycled in Example 1 of the present invention shows that the process of recycling and producing the mineralization membrane is simple, low-cost, and can realize the treatment of waste with waste, resource utilization of carbide slag solid waste, and recycling of heavy metal resources. It is economical, feasible, green and environmentally friendly.

[0061] Figure 4 This is a diagram showing the growth process of the metal basic salt mineralization membrane recovered and prepared in Example 1 of the present invention. As can be seen from the diagram, the mineralization membrane grows on its own in a static water sample, does not require external stirring, is energy-saving, and has low cost.

[0062] Figure 5 This is a schematic diagram illustrating the photocatalytic principle of Congo red CR using the metal basic salt mineralization membrane recovered and prepared in Example 1 of this invention. The diagram shows that the mineralization membrane generates H2O2 under visible light irradiation, which can exert a photo-Fenton synergistic effect to generate h2O2. + •O2 − •OH degrades Congo red CR, ultimately forming small molecule organic matter as well as H2O and CO2.

[0063] Figure 6 The figures shown in Example 1 of this invention illustrate the photocatalytic effect of the metal basic salt mineralization membrane recovered and prepared on Congo red CR. (a) shows the photocatalytic performance of Cu-MF on CR and the concentration of H2O2 produced; (b) shows the quenching results of Cu-MF on the photocatalytic active groups of CR; and (c) shows the effect of Cu-MF on the photocatalytic degradation of CR after 5 cycles and the Cu-MF concentration after each cycle. 2+ Leach concentration chart, from Figure 6 As can be seen in (a), the mineralization film exhibits excellent catalytic efficiency under visible light irradiation, achieving a decolorization and degradation rate of over 92% for Congo red, far exceeding the effects of visible light irradiation alone or the mineralization film alone. Particularly noteworthy is the generation of H2O2 during the reaction, which reacts with Cu in the mineralization film.+ A heterogeneous Fenton-like reaction occurs, especially under visible light irradiation, where the two exhibit a photo-Fenton synergistic effect, greatly promoting the decolorization and degradation of Congo red (CR). This demonstrates the excellent catalytic efficiency of the mineralized film as a visible light catalyst. Figure 6 As can be seen in (b), with different scavenging agents (tert-butanol (TBA), p-benzoquinone (BQ), and disodium ethylenediaminetetraacetate (EDTA-2Na) acting as hydroxyl radicals (•OH) and superoxide radicals (•O2), respectively... - ) and photogenerated holes (h + The addition of both the scavenging agent and the scavenging agent inhibited the degradation of Congo red CR, indicating that the main component responsible for the decolorization and degradation of Congo red CR during the photocatalytic process is h. + •O2 - And •OH; from Figure 6 As shown in (c), the Cu-MF mineralization membrane maintained a photocatalytic decolorization degradation rate of over 92% for CR after 5 cycles, indicating that the Cu-MF has excellent photocatalytic efficiency and stability. Furthermore, the Cu content in the water sample remained relatively low after each cycle. 2+ The leaching concentration was maintained between 2 and 3 mg / L, exhibiting low metal leaching characteristics. This maintained the catalyst's high efficiency, stability, and prevented it from being lost during the reaction, while also avoiding the possibility of secondary pollution of the water sample by the catalyst.

[0064] Figure 7 The image shows a microscopic SEM image of the metal basic salt mineralization film recovered and prepared in Example 1 of this invention. It can be seen from the image that the mineralization film grows into a flower-like bamboo leaf-shaped anhydrous Cu4SO4(OH)6 three-dimensional porous network structure, exhibiting a large surface area, which is suitable for use as a highly active heterogeneous photocatalyst.

[0065] Figure 8 The image shows the microscopic characterization of the metal basic salt mineralization film recovered and prepared in Example 1 of the present invention by EDS. It can be seen from the image that the mineralization film is rich in Cu, O and S.

[0066] Figure 9 The figure shows the elemental composition of the metal basic salt mineralization membrane recovered and prepared in Example 1 of this invention. As can be seen from the figure, the mass contents of the main elements Cu, O and S in the mineralization membrane are 51%, 39% and 7% respectively, and the atomic ratio is 19:66:6, which is basically consistent with the atomic ratio of each element in anhydrous Cu4(SO4)(OH)6 of 4:10:1. It belongs to a high-purity mineralization membrane. The mass content of Cu in this mineralization membrane reaches 51%, which is rich in metal-based Cu and is very suitable for use as a highly active heterogeneous photocatalyst.

[0067] Figure 10The image shows the microscopic characterization XRD pattern of the metal basic salt mineralization film recovered and prepared in Example 1 of this invention. The image reveals that the main mineral phase of the mineralization film is anhydrous Cu₄(SO₄)(OH)₆, rich in metal-based Cu and surface hydroxyl groups (OH). - It is suitable for use as a highly active heterogeneous photocatalyst.

[0068] Figure 11 This is a macroscopic photograph of the metal basic salt mineralization membrane recovered and prepared in Example 2 of the present invention. As can be seen from the figure, the mineralization membrane has a stable membrane structure, which can overcome the problems of easy agglomeration and difficulty in recycling of nanomaterials. It can be used as a low-cost heterogeneous stable catalyst, which is easy to separate solid and liquid, easy to recycle, and can be used multiple times.

[0069] Figure 12 The diagram above shows the process flow of the metal basic salt mineralization membrane recovered and prepared according to Example 2 of this invention, and the diagram below shows its Fenton-like catalytic principle for Congo red CR. The diagram above shows that the mineralization membrane recovery and preparation process is simple, self-growing in static water samples, requires no external stirring, is energy-saving, low-cost, and can achieve waste-to-waste treatment, resource utilization of carbide slag solid waste, and heavy metal resource recovery, making it economically feasible and environmentally friendly. The diagram below shows that the metal-based Cu and Fe of the mineralization membrane, used in combination with hydrogen peroxide, can exert a bimetallic Fenton-like effect on Congo red CR. Under the synergistic effect of the Cu-Fe bimetallic membrane on its surface, the mineralization membrane forms a highly efficient electron cycle, and the activation of H2O2 generates a large number of hydroxyl radicals (•OH) and superoxide radicals (•O2). - This promotes chain scission and decomposition of CR, ultimately forming small molecule organic compounds as well as CO2 and H2O, especially the intermediate product superoxide radical•O2 produced by the reaction. - A disproportionation reaction will also occur, generating a large amount of H2O2 and O2. The cyclic generation of H2O2 is very beneficial to the Fenton-like reaction. Furthermore, it is revealed that only a small amount of H2O2 needs to be added at the beginning of the reaction to achieve the desired effect, which can greatly save the amount of hydrogen peroxide used and reduce the cost of the reagents.

[0070] Figure 13 The figure shows the effect of the metal basic salt mineralization membrane recovered and prepared in Example 2 of the present invention on the Fenton-like catalytic effect of Congo red CR. It can be seen from the figure that the Fenton-like efficiency of the mineralization membrane combined with hydrogen peroxide is very excellent, and the decolorization and degradation rate of Congo red reaches more than 93.18%, which is far higher than the effect of hydrogen peroxide alone or mineralization membrane alone.

[0071] Figure 14The figures show the effects of multiple cycles of the metal basic salt mineralization membrane recovered and prepared in Example 2 of this invention. (a) represents 1-8 cycles, (b) 9-16 cycles, (c) 17-24 cycles, and (d) 25-32 cycles. As can be seen from the figures, the Cu / Fe-MF mineralization membrane exhibits excellent long-term stability. After 32 cycles, it still maintains high degradation capacity, and the decolorization degradation rate of Congo red is still above 93.18%. There is no significant activity decay, which fully demonstrates its application potential in actual wastewater treatment.

[0072] Figure 15 These are SEM images of the metal basic salt mineralization film recovered and prepared in Example 2 of this invention, where (a) is SEM 3000 and (b) is SEM 10000. Figure 15 As can be seen in (a), the Cu / Fe-MF mineralization film exhibits a flower-like spherical structure formed by the self-growth of nanosheets. The particles have regular morphology and good dispersion, with no obvious agglomeration. Under high magnification (b), the flower-like structure of the nanosheets is clear, with a large specific surface area and fine pores, which reserve space for the adsorption of CR molecules and the transport of H2O2, making it suitable as a highly active heterogeneous catalyst.

[0073] Figure 16 This is an EDS (Electrochemical Sedimentation) diagram of the metal basic salt mineralization film recovered and prepared in Example 2 of the present invention, where (c) represents EDS and (d) represents the proportion of each element. Figure 16 As can be seen from (c), this mineralized film is rich in Cu, Fe, and O. Figure 16 As shown in Figure (d), the main elements Cu, Fe, and O in this mineralized film have mass fractions of 34.76%, 23.45%, and 30.78%, respectively, and atomic percentages of 15.23%, 11.69%, and 53.56%. The high content and uniform distribution of these two metallic elements on the material surface further reveal that the mineralization process successfully achieved Cu… 2+ Fe 2+ With targeted resource recovery and uniform enrichment and loading of bimetallic active components, the mineralized film has a cumulative content of Cu and Fe elements of 58.21%, rich in metal-based Cu and Fe, making it very suitable as a highly active heterogeneous catalyst. In addition, the mass fraction of O element is 30.78% and the atomic fraction is 53.56%, mainly existing in the form of metal oxides and hydroxyl oxygen, which provides the necessary chemical environment for the activation of H2O2.

[0074] Figure 17The XRD patterns of the metal basic salt mineralization film recovered in Example 2 of this invention are shown before use and after 32 cycles. The figures show that the main mineral phase of the mineralization film is Cu₄(SO₄)(OH)₆(H₂O), and it also contains Cu₂O. Cu exists mainly in two valence states, and the Fe-related phase is FeO. This Fe valence state can directly participate in the activation of H₂O₂ in the Fenton-like reaction, providing a key material basis for the generation of hydroxyl radicals (·OH). Simultaneously, C was detected. 10 The structure H9Cu2Fe indicates that Cu and Fe elements are bonded together through coordination bonds to form a bimetallic composite mineral phase. This structure can provide crystalline phase support for the Cu-Fe synergistic catalytic effect through intermetallic electron transfer. The mineral phase remained stable before and after use, making this mineralized film suitable as a highly active bimetallic heterogeneous catalyst.

[0075] Figure 18 This is a macroscopic photograph of the metal basic salt mineralization membrane recovered and prepared in Example 3 of the present invention. As can be seen from the figure, the mineralization membrane has a stable membrane structure, which can overcome the problem of easy agglomeration and difficulty in recycling of nanomaterials. It can be used as a low-cost heterogeneous stable catalyst, which is easy to separate solid and liquid, easy to recycle, and can be used multiple times.

[0076] Figure 19 This is a schematic diagram of the preparation process of the composite particles (a) and the recycled metal basic salt mineralization membrane (b) in Example 3 of the present invention. As can be seen from the figure, the process of recycling the composite particles and mineralization membrane is simple, grows on its own in a static water sample, does not require external stirring, is energy-saving, low-cost, and can realize the treatment of waste with waste, resource utilization of carbide slag solid waste, and recovery of heavy metal resources. It is economical, feasible, green and environmentally friendly.

[0077] Figure 20 This is a SEM magnified image of the flower-like nanosphere crystals of the metal basic salt mineralization film in Example 3 of the present invention. As can be seen from the image, the mineralization film exhibits a flower-like nanosphere structure formed by the self-growth of nanosheets. The morphology is regular and well-dispersed, with no obvious agglomeration. It has a large specific surface area and contains fine pores, which reserve space for the adsorption of organic matter, the transport of H2O2 and light irradiation, making it suitable as a highly active heterogeneous catalyst.

[0078] Figure 21 This is a schematic diagram illustrating the photocatalytic Fenton effect of the metal basic salt mineralization film recovered and prepared in Example 3 of this invention on norfloxacin. As can be seen from the diagram, when light irradiates the material surface, electrons in its crystal lattice are photoexcited and jump from the valence band (VB) to the conduction band (CB), forming photogenerated electron-hole pairs. The band structure diagram shows that the conduction band (CB) potential of the material is -0.432 eV, which is lower than that of O2. - (O2 / ·O2 -The temperature (-0.33V vs. NHE) satisfies the thermodynamic electron transfer condition, allowing O2 to be generated by gaining electrons from the material's conduction band and undergoing a reduction reaction to produce ·O2. - The generated O2 - A portion of it can be found in h + With the help of oxidizing Fe@AA-MF from VB to 1 O2 and H2O2 react with Fe(II) to form ·OH + Fe(III). The Fe(III) generated during this reaction can be rapidly reduced back to Fe(II) by conduction-band photogenerated electrons. This not only achieves dynamic cyclic regeneration of Fe(II) / Fe(III) on the catalyst surface but also suppresses electron-hole recombination by consuming photogenerated electrons, further improving photocatalytic efficiency. Fe(III) can activate H2O2 to produce ·HO2, which further generates ·O2. - . 1 There are two ways O2 is generated: First, ·HO2 is generated through its own combination. Second, it is generated from ·O2. - It is generated through a reaction with ·OH. Ultimately, ·O2 is produced through the reaction of the above three substances. - ·OH 1 O2 and other components work together to gradually degrade NOR macromolecules into smaller molecule intermediates, ultimately mineralizing them into CO2, H2O, and F. - Inorganic ions are used to completely remove pollutants.

[0079] Figure 22 The figure shows the photocatalytic effect of the metal basic salt mineralization membrane recovered in Example 3 of this invention on norfloxacin photo-Fenton catalysis. It can be seen from the figure that under Vis (visible light) + H2O2 conditions, the degradation rate is only 7.19%, indicating that H2O2 cannot be activated to generate oxidizing active substances under light irradiation. When only Fe@AA-MF catalyst is used, the removal rate is 10.69%, at which point the removal of NOR relies on the adsorption performance of the catalyst itself. When Fe@AA-MF is used in photocatalytic Vis, H2O2, and photo-Fenton (Vis + H2O2) catalytic systems, the removal rates of NOR are 33.26%, 44.50%, and 97.10%, respectively. It can be seen that Fe@AA-MF material has the ability of heterogeneous Fenton and photocatalysis synergistic effect. Under the synergistic effect of the two, the photo-Fenton catalysis effect of Fe@AA-MF is significantly improved. The catalytic activity of the catalyst is excited by external visible light. At the same time, Fe(II) and Fe(III) contained in the catalyst participate in the reaction of oxidant H2O2 to generate more oxidative active substances (ROS), which greatly improves the degradation efficiency of NOR.

[0080] Figure 23The images shown are SEM and EDS images of the metal basic salt mineralization film recovered and prepared in Example 3 of this invention. (ac) represents the SEM image before the reaction, (df) represents the SEM image after the reaction, (gj) represents the EDS image before the reaction, and (kn) represents the EDS image after the reaction. Figure 23 As can be seen from the image (ac), the Fe@AA-MF mineralized film is mainly composed of a large number of well-dispersed, uniformly distributed, and uniformly sized nanoporous flower-like microspheres. After the reaction, the material ( Figure 23 The structure and shape of the material (df) remained basically unchanged; from the material before the reaction ( Figure 23 (in the middle (gj)), after the reaction ( Figure 23 As can be seen from the elemental distribution diagram of (kn), Fe, O, C and S elements are uniformly distributed on the surface of the material; Figure 24 The figure shows the proportion of each element in the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention. As can be seen from the figure, the relative atomic mass proportions of Fe, O, C and S are 47.99%, 36.51%, 13.74% and 1.76%, respectively. In particular, the proportion of highly active Fe element is as high as 47.99% and is uniformly distributed, indicating that the material is rich in metal Fe base and has excellent catalytic performance. It is an excellent heterogeneous catalyst material.

[0081] Figure 25 This is a particle size analysis diagram of the metal basic salt mineralization film recovered and prepared in Example 3 of the present invention. (p) represents the particle size analysis before the reaction, and (q) represents the particle size analysis after the reaction. As can be seen from the figure, the average particle size of the Fe@AA-MF mineralization film before (p) and after (q) the reaction is 119.56 nm and 97.02 nm, respectively. The average particle size after the reaction is 18.85% smaller than that before the reaction. This is mainly due to the Fe(II) / Fe(III) cycle in the catalytic reaction, indicating that Fe@AA-MF underwent skeletal reconstruction during the catalytic reaction. The smaller particle size and increased specific surface area are more conducive to the photo-Fenton reaction of Fe@AA-MF.

[0082] Figure 26 This is a graph showing the changes in BET specific surface area (a) and pore size (b) of the metal basic salt mineralization film recovered and prepared in Example 3 of this invention before and after the reaction. Figure 26 As can be seen in (a), the adsorption-desorption curves before and after the reaction exhibit typical hysteresis loops, indicating that they are type IV adsorption-desorption curves. This suggests that the material is primarily mesoporous, and the mesoporous structure prevents the aggregation and blockage of reaction products within the pores, further enhancing the kinetic efficiency of the heterogeneous catalytic reaction. Based on the shape of the hysteresis loop, it can be identified as an H3 type hysteresis loop, corresponding to the mesoporous structure formed by the accumulation of flower-like nanospheres. Figure 26In (a) and (b), the calculated specific surface area of ​​Fe@AA-MF is 138.25 m². 2 / g increased to 168.17m 2 / g, the number of macropores decreased, which indicates that during the catalytic reaction of the material, the macropores tend to spontaneously rearrange into mesopores, which is beneficial to improving the efficiency of heterogeneous catalytic reactions.

[0083] Figure 27 This is a graph showing the degradation and removal effect of norfloxacin in Comparative Example 1 of this invention. Fe(OH)3 is a commercially available Fe(OH)3 reagent, Fe-MF is a self-grown Fe mineralization film without ascorbic acid, and AA-Fe-MF is a self-grown mineralization film with ascorbic acid. As can be seen from the graph, the commercially available Fe(OH)3 reagent, being a powdery precipitate, is prone to agglomeration and lacks the network mineralization film structure formed by nanoporous flower-like microspheres, resulting in a lower photo-Fenton catalytic effect. For the self-grown Fe-MF without ascorbic acid, Fe(II) is easily oxidized during the film-forming mineralization process, easily forming precipitates, making it difficult to recover a complete mineralization film. It is also essentially powdery and lacks the ability to form nanoporous flower-like microspheres. The mesh-like mineralized membrane structure results in a lower photo-Fenton catalytic effect. However, when ascorbic acid is added, its polyhydroxy structure allows it to coordinate with heavy metal Fe ions in AMD, leading to a more dispersed, multi-site self-growth of Fe ions into a membrane. This also inhibits the rapid oxidation of low-valence metal Fe(II) to form a precipitate, resulting in a mineralized membrane containing multivalent metals Fe(II) and Fe(III). In particular, the formation of a mesh-like mineralized membrane structure by nanoporous flower-like microspheres enhances the catalytic and solid-liquid separation effects of the mineralized membrane. Under the synergistic effect of visible light and H2O2, Fe@AA-MF exhibits excellent degradation performance for NOR, with a removal rate of up to 97.10% within 60 minutes.

[0084] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a metal basic salt mineralization film, characterized in that, Includes the following steps: The composite particles and heavy metal wastewater are mixed and subjected to a hydration reaction under static conditions. The resulting colloidal liquid membrane adsorbs, precipitates, and crystallizes the heavy metal ions in the heavy metal wastewater to obtain particles with an outer metal basic salt mineralization membrane. There is a gap between the metal basic salt mineralization membrane and the particles in the particles with the outer metal basic salt mineralization membrane. The particles with the outer layer of metal basic salt mineralization film are separated to obtain the metal basic salt mineralization film and particles, which are then recycled separately. The method for preparing the composite particles includes the following steps: Sodium carbonate, bentonite, carbide slag and water are mixed and then granulated and dehydrated in sequence to obtain composite particles.

2. The preparation method according to claim 1, characterized in that, The heavy metal ions in the heavy metal wastewater include Cu. 2+ Fe 2+ Zn 2+ Mn 2+ Co 2+ and Ni 2+ One or more of the following; the concentration of heavy metal ions in the heavy metal wastewater is 150~1000 mg / L, and the pH value is 3.0~6.

5.

3. The preparation method according to claim 1 or 2, characterized in that, The ratio of the composite particles to the heavy metal wastewater is (0.1~3.5)g:(0.1~1)L.

4. The metal basic salt mineralization film prepared by the preparation method according to any one of claims 1 to 3, characterized in that, Its main component is a basic metal salt crystal.

5. The application of the metal basic salt mineralization membrane of claim 4 as a heterogeneous catalyst in the treatment of organic wastewater.

6. The application according to claim 5, characterized in that, The organic wastewater contains at least one of organic dyes and antibiotics; the organic dyes include one or more of Congo red, methylene blue, rhodamine b, and methyl orange; the antibiotics include one or more of norfloxacin, enoxacin, levofloxacin, and sulfadiazine; the concentration of organic dyes in the organic wastewater is 20-200 mg / L, and the concentration of antibiotics is 5-50 mg / L.

7. The application according to claim 5, characterized in that, The methods for treating organic wastewater include Fenton-like processes, photocatalytic processes, or photo-Fenton processes.

8. The application according to claim 7, characterized in that, The photocatalytic method involves adding a metal basic salt mineralization membrane to organic wastewater and conducting a photocatalytic reaction under visible light.

9. The application according to claim 7, characterized in that, The steps of the Fenton-like process are as follows: add the metal basic salt mineralization membrane and hydrogen peroxide to the organic wastewater, adjust the pH of the system to 3.0~9.5, and then carry out the Fenton-like catalytic reaction.

10. The application according to claim 7, characterized in that, The steps of the photo-Fenton method are as follows: adding a metal basic salt mineralization membrane and hydrogen peroxide to organic wastewater, and carrying out a photo-Fenton catalytic reaction under visible light irradiation.

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