Composite photocatalytic material, preparation method and application thereof

Abstract

The present application relates to the technical field of photocatalytic treatment of antibiotics in wastewater, and particularly relates to a composite photocatalytic material, a preparation method and application thereof. Melamine, palygorskite and water are mixed to obtain a mixed solution; the mixed solution is mixed with melamine foam, and after the melamine foam absorbs the mixed solution, drying is performed to obtain a precursor; the precursor is calcined to obtain the composite photocatalytic material. The composite photocatalytic material prepared by the present application can effectively improve the performance of the material in adsorbing antibiotics in water, enhance the photocatalytic degradation activity, and is easy to recycle, thus having a broad development prospect.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic treatment of antibiotics in wastewater, and in particular to a composite photocatalytic material, its preparation method, and its application. Background Technology

[0002] With rapid industrialization and urbanization, wastewater treatment has become an increasingly serious problem. Traditional wastewater treatment methods, such as biological treatment and chemical oxidation, have certain limitations, such as unstable treatment effects and high energy consumption. Therefore, researching new and efficient wastewater treatment technologies is of significant practical importance. Photocatalysis, as a method that uses light energy to activate catalysts and degrade organic antibiotic pollutants, has advantages such as mild reaction conditions, non-toxicity, and harmlessness, and is considered an important future development direction for the environmental protection industry. Therefore, in order to develop photocatalysis technology and solve the increasingly serious problem of various antibiotic pollution in water bodies, the research and development of new photocatalytic materials is imperative.

[0003] Attapulgite is a naturally occurring layered silicate mineral with a large specific surface area, good adsorption properties, and certain catalytic activity. In recent years, researchers have combined attapulgite with photocatalytic materials to develop a novel photocatalytic material—attapulgite-based photocatalytic material. This material exhibits good photocatalytic activity, stability, and reusability, providing a new approach for achieving efficient and green wastewater treatment. Attapulgite-based photocatalytic material possesses high photocatalytic activity, effectively degrading organic pollutants in water and improving wastewater treatment efficiency. Compared with traditional wastewater treatment methods, photocatalysis technology has lower energy consumption, contributing to energy conservation and sustainable development. Photocatalysis technology utilizes light energy to activate catalysts without the need for chemical reagents, thus reducing chemical pollution. Furthermore, it has excellent environmental performance, aligning with my country's strategic needs for energy conservation, emission reduction, and green development. The development and application of attapulgite-based photocatalytic materials will help improve the utilization value of attapulgite resources and promote the sustainable development of mining areas. In conclusion, the research and development of attapulgite-based photocatalytic materials and their application in wastewater treatment are of great theoretical and practical significance for solving my country's water pollution problems and achieving green development.

[0004] Melamine foam (nano-sponge) is a thermosetting elastic organic rubber-plastic foam with a fine three-dimensional network structure and high porosity, produced by microwave foaming of melamine polyformaldehyde resin. It is inexpensive and easily recyclable. Based on this, melamine foam's excellent comprehensive performance makes it widely used in architectural acoustics, aerospace applications, pipe insulation, supercapacitors, industrial cleaning, and water pollution adsorption. Graphitic carbon nitride (CN) is a novel visible light photocatalyst that has attracted widespread attention and research due to its excellent optical, thermal, and electrical properties. However, traditionally prepared CN precursors are mainly blocky structures with low specific surface area and severe interlayer stacking. This results in most of the introduced heteroatoms being distributed on the catalyst surface. In actual reactions, only a small amount of surface-modified catalyst can absorb light and be excited, causing a large portion of the modification to fail to play its role. To solve this problem, by loading it onto a three-dimensional porous network structure with a large specific surface area, photoexcitation can occur simultaneously on the catalyst surface and inside, allowing the internally modified portion to participate in the photocatalytic reaction. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a composite photocatalytic material, its preparation method, and its applications. The composite photocatalytic material provided by this invention utilizes melamine foam with a three-dimensional porous structure as a carrier to encapsulate g-C3N4 and ATP on its surface, forming a robust composite material. Notably, its large specific surface area and porous structure facilitate the adsorption of antibiotic pollutants in water during photocatalysis, thus laying the foundation for subsequent degradation and transformation. More importantly, as a three-dimensional foam structure material, it is easy to recycle and reuse. Preliminary research results show that under sunlight irradiation, the g-C3N4-ATP / 3D PCN composite photocatalytic material exhibits significant degradation effects on various antibiotics in water. Therefore, this work provides a theoretical basis and data support for the future rational design and preparation of highly efficient, durable, and stable three-dimensional porous photocatalysts.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing a composite photocatalytic material, comprising the following steps:

[0008] 1) Mix melamine, attapulgite clay, and water to obtain a mixture;

[0009] 2) Mix the mixture obtained in step 1) with melamine foam, and after the melamine foam absorbs the mixture, dry it to obtain the precursor;

[0010] 3) The precursor described in step 2) is calcined to obtain a composite photocatalytic material.

[0011] Preferably, the mass ratio of melamine, attapulgite clay and water in step 1) is 1~2:0.1:15.

[0012] Preferably, the mass ratio of melamine, attapulgite clay and water in step 1) is 1.5:0.1:15.

[0013] Preferably, the mixing conditions in step 1) include ultrasonic stirring for 30 minutes.

[0014] Preferably, the melamine foam in step 2) has a size of 2cm×2cm×2cm.

[0015] Preferably, the drying conditions in step 2) include: a temperature of 60°C and a time of 12 hours.

[0016] Preferably, the calcination conditions in step 3) include: a heating rate of 5°C / min, a temperature of 600°C, and a time of 2 hours.

[0017] The present invention also provides a composite photocatalytic material prepared by the preparation method described in the above technical solution.

[0018] This invention also provides the application of the composite photocatalytic material described in the above technical solution in the degradation of antibiotics.

[0019] Preferably, the composite photocatalytic material degrades antibiotics under sunlight;

[0020] The antibiotics include tetracycline.

[0021] The beneficial effects of this invention are:

[0022] (1) In this invention, ATP and melamine are used as raw materials and dispersed in deionized water. Then, melamine foam is added to the mixed solution. The fully adsorbed melamine foam composite precursor is transferred to a vacuum drying oven and kept at 60 °C for 12 h. After drying, it is cooled to room temperature. Then, the obtained melamine foam composite precursor is transferred to a closed tube furnace for calcination and annealing. After natural cooling, g-C3N4-ATP / 3D PCN composite photocatalytic material is obtained. The method of this invention is simple, has a short preparation time, low energy consumption, and the obtained g-C3N4-ATP / 3D PCN composite photocatalytic material has a unique morphology with rich pore structure and large specific surface area.

[0023] (2) The photocatalyst prepared in this invention, using g-C3N4-ATP / 3D PCN composite material as a photocatalyst and tetracycline hydrochloride antibiotic commonly found in water as a degradation product, was evaluated to assess its photocatalytic degradation and conversion performance of antibiotics in water, such as... Figure 3As shown in the figure. Test results indicate that g-C3N4, ATP, 3D PCN, and the g-C3N4-ATP / 3D PCN composite material all exhibit certain degradation activity against 100 ml of 20 mg / L tetracycline hydrochloride solution. Among them, the g-C3N4-ATP / 3D PCN composite material was able to completely degrade and convert tetracycline hydrochloride within 20 minutes, demonstrating extremely high catalytic activity. After five cycles of testing, it maintained high stability.

[0024] (3) The g-C3N4-ATP / 3D PCN composite photocatalytic material prepared by the present invention can effectively improve the adsorption performance of antibiotics in water, enhance the photocatalytic degradation activity and is easy to recycle, and has broad development prospects. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0026] Figure 1 This is the X-ray diffraction (XRD) pattern of the g-C3N4-ATP / 3D PCN composite photocatalytic material prepared in Example 1 of this invention;

[0027] Figure 2 These are scanning electron microscope (SEM) images of (A) ATP, (B) g-C3N4, (C) 3D PCN and (D) g-C3N4-ATP / 3D PCN composite photocatalytic materials prepared in Example 2 of this invention;

[0028] Figure 3 This is a graph showing the degradation performance of the g-C3N4-ATP / 3D PCN composite photocatalyst material prepared in Example 1 of this invention on 100 ml of a 20 mg / L tetracycline solution.

[0029] Figure 4 This is a graph showing the degradation performance of the g-C3N4-ATP / 3D PCN composite photocatalyst material prepared in Example 2 of this invention under different external conditions in a 100 ml, 20 mg / L tetracycline solution.

[0030] Figure 5 This is a graph showing the stability test of the g-C3N4-ATP / 3D PCN composite photocatalyst material prepared in Example 3 of this invention at 100 ml and 20 mg / L.

[0031] Figure 6This is a graph showing the degradation performance (general applicability) of the g-C3N4-ATP / 3D PCN composite photocatalyst material prepared in Example 3 of this invention on 100 ml of different antibiotic solutions at 20 mg / L. Detailed Implementation

[0032] This invention provides a method for preparing a composite photocatalytic material, comprising the following steps:

[0033] 1) Mix melamine, attapulgite clay, and water to obtain a mixture;

[0034] 2) Mix the mixture obtained in step 1) with melamine foam, and after the melamine foam absorbs the mixture, dry it to obtain the precursor;

[0035] 3) The precursor described in step 2) is calcined to obtain a composite photocatalytic material.

[0036] This invention involves mixing melamine, attapulgite, and water to obtain a mixture. In this invention, the preferred mass ratio of melamine, attapulgite, and water is 1-2:0.1:15. In this invention, the preferred mass ratio of melamine, attapulgite, and water is 1.5:0.1:15. In this invention, the preferred mixing conditions include ultrasonic stirring for 30 minutes.

[0037] This invention involves mixing the aforementioned mixture with melamine foam, and then drying the melamine foam after it has absorbed the mixture to obtain a precursor. In this invention, the melamine foam is preferably 2cm × 2cm × 2cm in size. The drying conditions are preferably: a temperature of 60°C and a time of 12 hours.

[0038] This invention involves calcining the precursor to obtain a composite photocatalytic material. The preferred calcination conditions include a heating rate of 5°C / min, a temperature of 600°C, and a time of 2 hours.

[0039] The present invention also provides a composite photocatalytic material prepared by the preparation method described in the above technical solution.

[0040] This invention also provides the application of the composite photocatalytic material described above in the degradation of antibiotics. In this invention, the composite photocatalytic material preferably degrades antibiotics under sunlight. In this invention, the antibiotic preferably includes tetracycline.

[0041] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1

[0043] A method for preparing a g-C3N4-ATP / 3D PCN composite photocatalytic material includes the following steps:

[0044] S1. Take 1.0 g of melamine and put it into a 100 ml beaker, then add 15 ml of water and 0.1 g of ATP, and sonicate for 30 min to obtain a mixed solution.

[0045] S2. Place the melamine foam (2cm*2cm*2cm) at the bottom of a beaker to fully absorb the dispersion of ATP and melamine; then transfer it to a vacuum drying oven at 60℃ and dry for 12 hours. Remove the precursor and place it in a ceramic boat, then transfer it to the middle part of a quartz tube and seal it. Heat to 600℃ at a heating rate of 5℃ / min and hold for 2 hours. Allow it to cool naturally. The final sample obtained is g-C3N4-ATP / 3D PCN, denoted as g-C3N4-ATP / 3D PCN-1.

[0046] Example 2

[0047] A method for preparing g-C3N4-ATP / 3D PCN nanomaterials includes the following steps:

[0048] S1. Take 1.5 g of melamine and put it into a 100 ml beaker, then add 15 ml of water and 0.1 g of ATP, and sonicate for 30 min to obtain a mixed solution.

[0049] S2. Place the melamine foam (2cm*2cm*2cm) at the bottom of a beaker to fully absorb the dispersion of ATP and melamine; then transfer it to a vacuum drying oven at 60℃ and dry for 12 hours. Remove the precursor and place it in a ceramic boat, then transfer it to the middle part of a quartz tube and seal it. Heat to 600℃ at a heating rate of 5℃ / min and hold for 2 hours. Allow it to cool naturally. The final sample obtained is g-C3N4-ATP / 3D PCN, denoted as g-C3N4-ATP / 3D PCN-2.

[0050] Example 3

[0051] A method for preparing g-C3N4-ATP / 3D PCN nanomaterials includes the following steps:

[0052] S1. Take 2.0 g of melamine and put it into a 100 ml beaker, then add 15 ml of water and 0.1 g of ATP, and sonicate for 30 min to obtain a mixed solution.

[0053] S2. Place the melamine foam (2cm*2cm*2cm) at the bottom of a beaker to fully absorb the dispersion of ATP and melamine; then transfer it to a vacuum drying oven at 60℃ and dry for 12 hours. Remove the precursor and place it in a ceramic boat, then transfer it to the middle part of a quartz tube and seal it. Heat to 600℃ at a heating rate of 5℃ / min and hold for 2 hours. Allow it to cool naturally. The final sample obtained is g-C3N4-ATP / 3D PCN, denoted as g-C3N4-ATP / 3D PCN-3.

[0054] Performance testing:

[0055] 1. The phase structure of the g-C3N4-ATP / 3D PCN composite photocatalytic materials prepared in Examples 1-3 was analyzed using an XRD instrument.

[0056] Figure 1 The XRD patterns of the g-C3N4-ATP / 3D PCN composite photocatalyst materials prepared in Examples 1-3 are shown below. Figure 1 As shown, diffraction peaks were observed at approximately 19.96°, 26.68°, 30.9°, 35.1°, 41.2°, 50.6°, and 61.4°, which are attributed to ATP (JCPS NO: 29-0855). Characteristic peaks at 13.2° and 27.7° are attributed to the (100) and (002) crystal planes of g-C3N4. Notably, the characteristic peak of pure 3D PCN after high-temperature calcination is located at 27.2°. When the g-C3N4-ATP / 3DPCN composite photocatalyst material was formed, characteristic peaks of g-C3N4, ATP, and 3D PCN appeared simultaneously, indicating that the composite material is composed of the above-mentioned substances. Therefore, the g-C3N4-ATP / 3D PCN composite photocatalyst material was successfully synthesized by XRD analysis.

[0057] 2. The microstructure of the g-C3N4-ATP / 3D PCN composite photocatalytic material prepared in Example 1 was analyzed by SEM.

[0058] Figure 2 The image shows a SEM image of the g-C3N4-ATP / 3D PCN composite photocatalyst material prepared in Example 1. Figure 2 A is pure attapulgite (ATP), which has a fibrous rod-like structure with rods about ten nanometers in diameter. The rods are irregular in structure and vary in length. Figure 2In contrast, pure g-C3N4 (B) exhibits a thin, lamellar structure with wrinkled and curled edges and a high content of porous structures. Even after calcination, the three-dimensional melamine foam retains its porous network structure, with relatively smooth surfaces on each edge, although some edges show signs of breakage. Notably, when the g-C3N4-ATP / 3D PCN composite photocatalyst material is formed, the three-dimensional network structure is maintained as a carrier, with each pore and edge covered by a layer of network and lamellar material, which are respectively derived from fibrous rod-shaped attapulgite and g-C3N4. This three-dimensional porous network structure not only enhances light absorption and utilization and provides numerous adsorption and catalytically active sites, but also shortens charge transport distances, promoting charge separation and rapid transfer.

[0059] 3. The photocatalytic degradation performance of the g-C3N4-ATP / 3D PCN composite photocatalyst materials prepared in Examples 1-3 was analyzed using a liquid ultraviolet spectrometer (UV-1800PC) for tetracycline hydrochloride degradation. The specific steps were as follows: The photocatalytic degradation reaction was carried out in a quartz reactor. The light source used was a 300 W xenon lamp equipped with a filter (λ>420 nm). The photocatalytic activity of g-C3N4-ATP / 3D PCN was evaluated by degrading TC·HCl under visible light irradiation. Typically, 20 mg of catalyst was added to a TC·HCl solution (100 mL, 20 mg L⁻¹). The solution was stirred in the dark for 60 minutes to reach adsorption-desorption equilibrium, and then the photocatalytic degradation experiment was performed. Every 5 minutes, 1 mL of the suspension was filtered through a 0.45 μm Millipore filter to separate solid particles. The concentration of TC·HCl was measured using a Shimadzu UV-Vis spectrophotometer (350 nm). No photocatalytic degradation performance was observed without the catalyst. Under visible light irradiation, calcined 3D PCN (melamine foam heated to 600°C at a heating rate of 5°C / min and held for 2 hours in a closed tube furnace) exhibits almost no catalytic activity, only adsorption activity. Furthermore, under visible light irradiation, pure g-C3N4 (melamine powder heated to 600°C at a heating rate of 5°C / min and held for 2 hours in a closed tube furnace) can degrade 95% of a 100 ml, 20 mg / L tetracycline hydrochloride solution within 60 minutes. Attapulgite also shows some degradation activity, degrading approximately 66.3% of the tetracycline hydrochloride solution within 60 minutes. When attapulgite and g-C3N4 are physically mixed, their photocatalytic activity falls between the two, degrading approximately 83.9% of the tetracycline hydrochloride solution within 60 minutes. It is worth noting that the prepared g-C3N4-ATP / 3D PCN composite photocatalyst material can completely degrade 100 ml of 20 mg / L tetracycline hydrochloride solution within 20 minutes, exhibiting the best photocatalytic activity. Figure 4This study investigated the effect of varying g-C3N4 content on the photocatalytic degradation performance of tetracycline hydrochloride. With increasing g-C3N4 content, the photocatalytic activity exhibited a volcanic trend, with g-C3N4-ATP / 3D PCN-2 demonstrating the best activity, capable of completely degrading 100 ml of a 20 mg / L tetracycline hydrochloride solution within 20 minutes. In contrast, g-C3N4-ATP / 3D PCN-1 and g-C3N4-ATP / 3D PCN-3 required 35 minutes and 30 minutes, respectively, to completely degrade the same solution. Furthermore, the photocatalytic cycling stability of the prepared g-C3N4-ATP / 3D PCN-2 was tested. Figure 5 As shown in the diagram, in the first cycle, it completely degraded 100 ml of 20 mg / L tetracycline hydrochloride solution within 20 minutes. After five cycles, it still managed to degrade 98.5% of the 100 ml of 20 mg / L tetracycline hydrochloride solution within 20 minutes, maintaining high activity. It is noteworthy that g-C3N4-ATP / 3DPCN-2 not only exhibits excellent photocatalytic activity in degrading tetracycline hydrochloride, but also degrades other antibiotics (ciprofloxacin, norfloxacin, roxithromycin, metronidazole, sulfonamides, sulfamethoxazole, trimethoprim), such as... Figure 6 As shown, 100 ml of 20 mg / L sulfamethoxazole solution was completely degraded within 20 minutes. Ciprofloxacin, roxithromycin, metronidazole, sulfonamides, and trimethoprim were all degraded by more than 84% within 60 minutes. Even norfloxacin, which has a relatively slow degradation rate, was degraded by 66.3% within 60 minutes from 100 ml of 20 mg / L norfloxacin solution. Based on the above analysis, g-C3N4-ATP / 3D PCN-2 not only possesses excellent photocatalytic activity for the degradation of tetracycline hydrochloride and broad applicability to the degradation of various antibiotics, but also exhibits excellent cyclic stability, making it a potential photocatalyst for antibiotic degradation.

[0060] 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 composite photocatalytic material, characterized in that, Includes the following steps: 1) Mix melamine, attapulgite clay, and water to obtain a mixture; 2) Mix the mixture obtained in step 1) with melamine foam, and after the melamine foam absorbs the mixture, dry it to obtain the precursor; 3) The precursor described in step 2) is calcined to obtain a composite photocatalytic material.

2. The preparation method according to claim 1, characterized in that, In step 1), the mass ratio of melamine, attapulgite, and water is 1~2:0.1:

15.

3. The preparation method according to claim 1, characterized in that, In step 1), the mass ratio of melamine, attapulgite, and water is 1.5:0.1:

15.

4. The preparation method according to claim 1, characterized in that, Step 1) The mixing conditions include: ultrasonic stirring for 30 minutes.

5. The preparation method according to claim 1, characterized in that, Step 2) The melamine foam has a size of 2cm×2cm×2cm.

6. The preparation method according to claim 1, characterized in that, Step 2) The drying conditions include: a temperature of 60°C and a time of 12 hours.

7. The preparation method according to claim 1, characterized in that, Step 3) The calcination conditions include: a heating rate of 5℃ / min, a temperature of 600℃, and a time of 2h.

8. A composite photocatalytic material prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the composite photocatalytic material according to claim 8 in the degradation of antibiotics.

10. The application according to claim 9, characterized in that, The composite photocatalytic material degrades antibiotics under sunlight; The antibiotics include tetracycline.

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