Preparation method of Cu2O / black phosphorus catalyst for removing antibiotics from water

Abstract

This invention belongs to the field of environmental chemical catalytic water treatment technology and discloses a method for preparing a Cu2O / black phosphorus catalyst for removing antibiotics from water. Using Cu2O and black phosphorus (BP) as precursor reactants, a series of Cu2O / BP composite photocatalysts were prepared. The BP catalyst was prepared by a simple hydrothermal method. Then, Cu(NO3)2·3H2O and BP were calcined in varying proportions to form the composite Cu2O / BP photocatalysts. Analysis revealed that the Cu2O was loaded onto the BP layer, forming a composite structure. The prepared catalysts were used to degrade levofloxacin hydrochloride under visible light, and the catalytic activity of the composite photocatalysts was evaluated. Results showed that among the photocatalysts with varying Cu2O / BP loadings, 3% and 4% Cu2O / BP exhibited the best photocatalytic degradation performance, achieving a degradation rate of 89% in 3 hours, 2.83 times that of pure BP. This demonstrates the successful preparation of highly efficient composite catalysts.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental chemical catalytic water treatment, relates to visible light treatment to generate clean gas, and particularly relates to a method for preparing a Cu2O / black phosphorus catalyst for removing antibiotics from water. Background Art

[0002] Due to the high pollution concentrations of compound antibiotic wastewater, treatment is usually carried out using a combination of physical, biological, and advanced oxidation processes. However, as far as current domestic and international technologies are concerned, no technology has achieved significant and more specific results. Therefore, antibiotic wastewater treatment is a major concern at this stage, and oxidation treatment measures are needed to effectively treat wastewater with significant treatment effects to protect the quality of people's living environment. Antibiotic wastewater contains intermediate metabolites, surfactants, and high concentrations of acids, bases, and organic solvents. Due to its complex composition, it is easy to cause pH fluctuations and affect biochemical effects during extraction and separation procedures. Currently, the more practical methods for treating water pollution include photocatalysis, adsorption, and membrane separation. Among them, photocatalysis can use solar energy to convert hydrogen energy for storage and can also be used to degrade organic wastewater. However, efficiency and cost are the main factors restricting the development of photocatalysis. Therefore, it is imperative to find a substance that can efficiently and cost-effectively degrade antibiotics in the environment.

[0003] Black phosphorus (BP) is a form of phosphorus in nature, and is an allotrope of the common flammable red phosphorus. The preparation of BP crystals began as early as 100 years ago. BP crystals are composed of a single layer of black phosphorus flakes. BP is a p-type semiconductor, and its light absorption range can cover the ultraviolet-visible-near infrared range. The adjustable range has great advantages compared to other semiconductors. Although BP has excellent photocatalytic properties, it is easily oxidized and decomposed in oxygen-containing air, water and visible light, and its properties are unstable. Therefore, it is necessary to continue to explore and study the modification of BP, which can retain its original photocatalytic properties and improve its stability.

[0004] Copper is an element in Group 11 of the periodic table. A transition metal, copper is naturally abundant, with the greatest advantages of being non-toxic and widely available. At room temperature, copper has the second-highest electrical and thermal conductivity of all pure metals, second only to silver. Its high ductility makes it a frequently used material in industrial products. Cu2O is one of the most studied transition metal oxide crystals, as the electrical and optical properties of the semiconductor Cu are particularly useful in solar cells and technological devices. Cu2O exhibits p-type conductivity and is inexpensive to produce, effectively absorbing sunlight. Its high absorption coefficient makes it potentially useful in solar cell fabrication, and its stability makes it highly stable. Therefore, Cu2O has great potential for applications in solar energy conversion and photocatalysis. Nanowire photocathodes have been developed, reportedly the most efficient metal oxide material currently available. Furthermore, Cu2O can be formed into semiconducting thin films, offering great potential for electron transport. Summary of the Invention

[0005] Because BP is easily oxidized and decomposed in oxygen-containing air, water, and visible light, resulting in inefficiency and unstable properties, research has explored modifying BP in ways that both retain its original photocatalytic properties and enhance its stability. Cu2O is one of the most studied transition metal oxide crystals, with promising applications in solar energy conversion and photocatalysis. It is currently the most effective metal oxide material. Furthermore, Cu2O can be formed into a semiconductor thin film, offering promising development prospects for electron transfer. The present invention combines the two, avoiding their respective shortcomings to produce a highly efficient composite metal photocatalyst. The study examined the effects of varying concentrations of Cu2O combined with BP on the degradation and photocatalytic performance of levofloxacin hydrochloride wastewater.

[0006] In order to solve the problems mentioned in the background technology, the purpose of the present invention is to provide a Cu2O / BP catalyst and a preparation method having good photocatalytic properties and providing new ideas for subsequent wastewater degradation.

[0007] The present invention mainly achieves the above-mentioned object by improving the catalyst composition and preparation method. To achieve this object, the present invention provides:

[0008] A Cu2O / black phosphorus catalyst for removing antibiotics from water is prepared by first synthesizing a BP nanolayer, then synthesizing Cu2O particles and finally loading BP on them. The Cu2O material is in the form of spherical bodies, and the BP has a clear layered structure. The synthesized composite material is in the shape of spherical nanoparticles embedded in the layered structure.

[0009] On the other hand, a method for preparing the above-mentioned Cu2O / black phosphorus catalyst for removing antibiotics in water is provided, comprising the following steps:

[0010] (1) Preparation of BP: 0.25-0.75 g of red phosphorus was first ground into powder using a pestle and mortar, and then 70-80 mL of ethylenediamine was added. After vigorous stirring with a magnetic stirrer for 30 min, the mixture was transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave and placed in a constant temperature drying oven. After heating at 165°C for 24 h, the mixture was rapidly cooled to room temperature and the product was collected with cold water. After centrifugation, the product was washed three times with ethanol to remove the residual solvent ethylenediamine. The final product was dried in a vacuum at 40°C.

[0011] (2) Preparation of Cu2O: Dissolve 0.004 mol of Cu(NO3)2·3H2O in 70–90 mL of EG. After stirring for 2 h, the clear, pale blue solution was transferred to a 100 mL autoclave (stainless steel autoclave), sealed, and transferred to an oven, where it was heated to 180°C for 2 h. The final yellow product was filtered and washed several times with ethanol to remove unreacted EG, and then dried in air at 40°C.

[0012] (3) Preparation of Cu2O / BP: The prepared Cu2O and BP powders were dissolved in 80 mL of EG (1 g of BP powder, with a Cu2O to BP mass ratio of 1% to 10%). After stirring for 2 h, the transparent light blue solution was transferred to a 100 mL autoclave (stainless steel autoclave), sealed, and transferred to an oven, where it was heated to 180°C for 2 h. The final yellow product was filtered and washed several times with ethanol to remove unreacted EG, and then dried in air at 40°C.

[0013] On the other hand, the invention provides the application of composite catalyst Cu2O / BP in photocatalytic degradation of levofloxacin hydrochloride wastewater.First, 3-5mg pure Cu2O, pure BP and the Cu2O / BP composite catalyst having compounded different proportions are respectively taken and added into 100mL levofloxacin hydrochloride (10mg / L). Then, under dark conditions, stirring 60min sets up the adsorption-desorption equilibrium between catalyst and levofloxacin hydrochloride solution. A 500w xenon lamp is vertically placed 15cm above the solution. 4mL is sampled at regular intervals and transferred into a centrifuge tube, and the photocatalyst is separated by centrifugation. Finally, an ultraviolet-visible spectrophotometer is used to measure the absorbance at 294nm. The variation of levofloxacin hydrochloride concentration is determined by absorbance to analyze the degradation efficiency of the photocatalyst.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. The composite Cu2O / BP catalyst is composed of Cu2O particles and BP particles. The BP nanolayer is prepared first and then loaded with Cu2O.

[0016] 2. The composite Cu2O / BP catalyst has strong light adsorption ability and high electron-hole separation efficiency. The material structure is stable, the photogenerated carrier transmission is fast, and the recombination of photogenerated carriers can be effectively suppressed.

[0017] 3. Compared with pure Cu2O and BP, the composite Cu2O / BP catalyst has better visible light absorption performance and greatly improves the photocatalytic degradation of levofloxacin hydrochloride solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 (a) is a scanning electron micrograph of Cu2O of Example 1, (b) is a scanning electron micrograph of BP of Example 1, and (c) is a scanning electron micrograph of 3% Cu2O / BP;

[0019] Figure 2 The photoelectron spectra of Cu2O, BP, and 3%Cu2O / BP in Example 1 are shown;

[0020] Figure 3 The infrared spectra of Cu2O, BP and 3%Cu2O / BP in Example 1 are shown;

[0021] Figure 4 The UV-visible diffuse reflectance spectra of Cu2O, BP, and 3% Cu2O / BP in Example 1 are shown;

[0022] Figure 5 The fluorescence spectra of Cu2O, BP and 3%Cu2O / BP in Example 1 are shown;

[0023] Figure 6 This is a graph showing the removal rate of levofloxacin hydrochloride degraded by different catalysts under visible light irradiation in Example 1. DETAILED DESCRIPTION

[0024] The following non-limiting examples are provided to provide a more comprehensive understanding of the present invention to those skilled in the art, but are not intended to limit the present invention in any way. Unless otherwise specified, the experimental methods employed in the present invention are conventional methods, and the experimental equipment, materials, and reagents used are all commercially available.

[0025] Example 1

[0026] The preparation method of the composite Cu2O / BP catalyst is as follows:

[0027] Composite materials containing different mass ratios of BP and Cu2O were prepared by varying the Cu2O content of the mixed solution before calcination while maintaining the BP content constant. The photocatalysts thus prepared are denoted as Cu2O / BP(x:y), where x:y is the mass ratio of Cu2O to BP. Cu2O / BP composite catalysts with different mass ratios (1%, 2%, 3%, 4%, 5%, and 10%) were prepared using the following method: Different amounts of Cu(NO3)2·3H2O and 1 g of the prepared BP powder were dissolved in 80 mL of EG. After stirring for 2 hours, the clear, light blue solution was transferred to a 100 mL autoclave (stainless steel autoclave), sealed, and transferred to an oven, where it was heated to 180°C for 2 hours. The final yellow product was filtered, washed several times with ethanol to remove unreacted EG, and dried in air at 40°C.

[0028] Example 2

[0029] 0.5 g of red phosphorus was ground into a powder using a pestle and mortar, followed by the addition of 75 mL of ethylenediamine. After vigorous stirring with a magnetic stirrer for 30 minutes, the mixture was transferred to a 100 mL Teflon-lined stainless steel autoclave and placed in a constant-temperature drying oven. After heating at 165°C for 24 hours, the mixture was rapidly cooled to room temperature and collected with cold water. After centrifugation, the product was washed three times with ethanol to remove residual ethylenediamine solvent. The final product was dried in a vacuum at 40°C to obtain BP.

[0030] Example 3

[0031] Dissolve 0.004 mol of Cu(NO₃)₂·3H₂O in 80 mL of EG. After stirring for 2 hours, the clear, light blue solution was transferred to a 100 mL autoclave (stainless steel autoclave), sealed, and transferred to an oven, where it was heated to 180°C for 2 hours. The final yellow product was filtered, washed several times with ethanol to remove unreacted EG, and dried in air at 40°C. Cu₂O was obtained.

[0032] Figure 1 The scanning electron microscope images of Cu2O, BP and 3%Cu2O / BP in Example 1 are shown; Figure 1 a, is the SEM image of BP material at 10nm. It can be seen from Figure (a) that BP has a clear layered structure. Figure 1 b is the SEM image of Cu2O nanomaterials at 1 μm. It can be seen from the figure that Cu2O exhibits a spherical shape and is connected into a rod shape. Figure 1 As shown in (c), the structure of the Cu2O / BP composite material can be seen, and Cu2O nanoparticles are adsorbed on the layered BP.

[0033] Figure 2The photoelectron spectra of Cu2O, BP and Cu2O / BP in Example 1 confirm the presence of Cu, O and P elements in the Cu2O / BP structure.

[0034] Figure 3 The infrared spectra of Cu2O, BP and 3% Cu2O / BP in Example 1 are shown in the figure. As shown in the figure, in the infrared spectrum of Cu2O, the -1 The peak at corresponds to the stretching vibration of the Cu-O bond. The corresponding characteristic peak can also be seen in the composite sample, confirming that Cu2O / BP is composed of Cu2O and BP.

[0035] Figure 4 The UV-visible diffuse reflectance spectra of all samples in Example 1 are shown below. Black phosphorus has a wide absorption range and excellent light absorption ability. Cu2O has an absorption peak at 400-600nm and weak light absorption ability. The absorption peaks of Cu2O / BP with different ratios are all in the middle of the two pure samples. Compared with Cu2O, the composite samples have a wider visible light absorption range.

[0036] Figure 5 Figure 2 is the fluorescence spectrum of all samples in Example 1; as shown in the figure, the PL intensity of Cu2O and BP is higher than that of the Cu2O / BP composite material, and the PL intensity of the Cu2O / BP composite material is reduced, indicating that the presence of BP reduces the PL intensity, effectively separates the photogenerated electron-hole pairs, reduces the recombination of photogenerated electron-hole pairs, and realizes effective electron transfer.

[0037] Figure 6 The removal rate of levofloxacin hydrochloride degradation by different catalysts under visible light irradiation in Example 1; Application Example 1

[0038] First, 3-5 mg of pure Cu2O, pure BP, and Cu2O / BP composite catalysts in different proportions (1%, 2%, 3%, 4%, 5%, and 10%) were added to 100 mL of levofloxacin hydrochloride (10 mg / L). The mixture was then stirred in the dark for 60 minutes to establish an adsorption-desorption equilibrium between the catalyst and the levofloxacin hydrochloride solution. A 500W xenon lamp was placed vertically 15 cm above the solution. 4 mL of the sample was taken at regular intervals and transferred to a centrifuge tube for centrifugation to separate the photocatalyst. Finally, an ultraviolet-visible spectrophotometer was used to measure the absorbance at 294 nm. The changes in the levofloxacin hydrochloride concentration were determined by the absorbance to analyze the degradation efficiency of the photocatalyst.

[0039] The experimental results are shown in Figure 6As shown in the figure, a mixture of catalyst and levofloxacin hydrochloride was placed under a 500W xenon lamp. It is clear from the figure that pure BP degraded levofloxacin hydrochloride at a mere 31.45% efficiency, while the Cu2O / BP composite material significantly outperformed the two pure samples, with the Cu2O degradation rate only reaching 10%. Among the composite samples, the 1% Cu2O / BP degradation rate was the lowest at only 65% ​​after 180 minutes. The 3% and 4% Cu2O / BP samples were very effective, both reaching 89%. The remaining 2%, 5%, and 10% Cu2O / BP samples showed more moderate degradation, ranging from 70% to 76%. Overall, the composite catalysts still achieved higher degradation rates for the antibiotic than the pure samples, with the best achieving a 2.83-fold improvement in degradation efficiency compared to BP.

[0040] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a Cu2O / black phosphorus catalyst for removing antibiotics in water, characterized in that: The following steps are involved: (1) Preparation of BP: 0.25-0.75 g of red phosphorus powder was added to 70-80 mL of ethylenediamine, mixed evenly, and then transferred to a polytetrafluoroethylene-lined stainless steel autoclave. The mixture was placed in a constant temperature drying oven and heated at 165 °C for 24 h. The mixture was then rapidly cooled to room temperature and the product was collected with cold water. After centrifugation, the product was washed with ethanol and dried in a vacuum at 40 °C. (2) Weigh Cu2O. The preparation method of Cu2O is as follows: dissolve 0.004 mol Cu(NO3)2·3H2O in 70-90 mL EG, stir for 2 h, transfer to an autoclave or stainless steel autoclave, seal and transfer to an oven, then heat to 180°C and hold for 2 h. Filter the final yellow product, wash with ethanol, and dry in air at 40°C. (3) Preparation of Cu2O / BP: Dissolve Cu2O and BP powder in 80 mL of EG, with 1 g of BP powder and a mass ratio of Cu2O to BP of 1%-10%. After stirring for 2 h, transfer the mixture to an autoclave or stainless steel autoclave, seal it, and transfer it to an oven. Then, heat it to 180 °C and keep it for 2 h. Filter the final yellow product, wash it with ethanol to remove unreacted EG, and dry it in air at 40 °C.

2. The method for preparing the Cu2O / black phosphorus catalyst for removing antibiotics in water according to claim 1, characterized in that: Wash with ethanol three more times.

3. A Cu2O / black phosphorus catalyst for removing antibiotics from water, characterized in that: The Cu2O / black phosphorus catalyst is prepared according to the method according to any one of claims 1-2.

4. An application of a Cu2O / black phosphorus catalyst for removing antibiotics from water, characterized in that: The Cu2O / black phosphorus catalyst is prepared according to the method according to any one of claims 1-2, and is used in the photocatalytic degradation of levofloxacin hydrochloride wastewater.

5. The use of the Cu2O / black phosphorus catalyst for removing antibiotics in water according to claim 4, characterized in that: 3-5 mg of Cu2O / BP composite catalyst was added to 100 mL of 10 mg / L levofloxacin hydrochloride, and then stirred for 60 min in the dark to establish the adsorption-desorption equilibrium between the catalyst and the levofloxacin hydrochloride solution, and the xenon lamp was vertically irradiated.

6. The use of the Cu2O / black phosphorus catalyst for removing antibiotics in water according to claim 5, characterized in that: When irradiated by a xenon lamp, a magnetic stirring bar should be added to the levofloxacin hydrochloride solution containing a catalyst, and the solution should be placed on a magnetic stirrer to continue stirring the reaction.

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