Preparation method of TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics

Abstract

The present invention discloses a preparation method of a catalyst for photocatalytic activation of PMS to degrade ECs based on TiO2-in-CNT / Co3O4. The catalyst is a nanocomposite with carbon nanotubes as the main body, TiO2 embedded in the tubes, and Co3O4 loaded outside the tubes. The prepared TiO2-in-CNT / Co3O4 of the present invention can activate PMS under visible light photocatalysis to effectively degrade ECs. The prepared TiO2-in-CNT / Co3O4 catalyst has regular morphology, simple preparation, low cost, and is suitable for large-area popularization and application.

Description

Technical Field

[0001] The present invention relates to the field of ECs treatment, and particularly to a preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics. Background Art

[0002] As is well known, the rapid development of modern industry has brought about an excellent quality of life, but it has also caused quite a number of social problems that cannot be ignored. Among them, the water safety crisis caused by emerging pollutants has seriously affected the survival of humans and other organisms. Antibiotics are essential drugs for animal health, agriculture, and aquaculture. As a large class of typical emerging pollutants (ECs), the annual consumption of antibiotics exceeds 100,000 tons, and the half-life is as long as 77 days. The large-scale production and wide application of antibiotics have caused potential harm to the water environment and ecosystem. Norfloxacin (NOR) is a member of the fluoroquinolone antibiotics. Due to its high activity against Gram-negative and Gram-positive bacteria, it has been widely used in clinical, veterinary, and aquaculture. Unfortunately, NOR in animals or humans cannot be fully metabolized. Most of them enter the environment with excreta. The widespread use has increased the detectable concentration of NOR in the environment, reaching the ng / L - μg / L level in urban wastewater and even the "mg / L" level in pharmaceutical wastewater. NOR in the environment can easily change the microbial community structure in the environment by interfering with bacterial DNA replication, and at the same time, it will also lead to the generation of drug-resistant bacteria. It has been proven that NOR may pose potential ecological risks to human health and the ecosystem. Therefore, exploring how to efficiently and greenly remove NOR treatment technology from wastewater has become one of the focuses of researchers' attention.

[0003] So far, technologies including adsorption, biodegradation, and chemical degradation have been developed to solve antibiotic pollutants. Advanced oxidation processes (AOPs) have been proven to be an effective technology for degrading these refractory pollutants by using highly reactive free radicals. In recent years, the advanced oxidation technology based on peroxymonosulfate (PMS) has attracted much attention due to its low cost, high efficiency, strong stability, and good adaptability. Once activated by a catalyst, PMS can release ·OH and ·SO4 - to decompose pollutants because their high redox potentials (1.8 - 2.7V and 2.5 - 3.1V respectively) and long half-lives (30 - 40 μs) are conducive to promoting pollutant degradation. Generally speaking, the reactions involved can be divided into two types. One is free radical oxidation mainly based on ·OH and ·SO4 - and the other is electron transfer. 1Non-radical oxidation mainly based on O2 and high-valent metals. Currently, the activation methods of PMS include electrolysis, heating, ultrasonic waves, and activation by transition metal (Fe, Co, Ni)-based substances. These methods have simple reactions and low energy consumption, and have been gradually widely studied. Since cobalt ions show strong catalytic ability for PMS, among various transition metal oxides, Co-containing oxide nanomaterials are used as common PMS activators. Especially spinel-type Co3O4 is more attractive due to its low cost and excellent redox performance. However, in the process of activating PMS by transition metal-based catalysts, there are still problems to be solved, such as poor metal ion recycling and metal ion leaching. To solve the above problems, a suitable carrier can be selected to provide a large specific surface area to support Co oxide nanoparticles. The combination of photocatalysis and activation of PMS can promote the recycling of metal ions and produce a synergistic effect. TiO2 has been widely used in photocatalytic hydrogen production, solar cells, treatment of pollutants, etc. due to its inherent characteristics such as non-toxicity, good stability, and low cost. In recent years, one-dimensional nanomaterials such as CNTs with a large specific surface area have been widely studied. Confining nanoparticles inside CNT tubes can increase the interaction between the metal and the carrier, form an active interface between the metal and the carrier, and enhance the electron transfer efficiency.

[0004] In this paper, a nanocomposite material with TiO2 embedded in carbon nanotubes (CNT) and Co3O4 loaded outside the tubes was designed and synthesized. This nanocomposite material with TiO2 confined inside the CNT tubes and Co3O4 loaded outside the tubes combines photocatalysis with the activation of PMS by transition metal-based oxide Co3O4.

[0005] Based on the above technical background, the present technical invention designed and synthesized a nanocomposite material TiO2-in-CNT / Co3O4 with TiO2 embedded in carbon nanotubes (CNT) and Co3O4 loaded outside the tubes, which has excellent performance in photocatalytic activation of PMS for degrading ECs, and no relevant technologies have been reported. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems existing in the prior art and provide a preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics.

[0007] To achieve the above purpose, the technical solution provided by the present invention is: a preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics. The catalyst is a nanocomposite material with carbon nanotubes as the main body, TiO2 embedded inside the tubes, and Co3O4 loaded outside the tubes. The preparation method of the catalyst includes the following specific steps:

[0008] (1) Preparation of TiO2-in-CNT: CNT was treated with nitric acid by a conventional method to obtain open carboxyl-functionalized CNT. 1 mL of TiCl4 was uniformly dissolved in 10 mL of ethanol to obtain a mixed solution A. Then, 2 mL of the mixed solution A and a certain amount of open carboxyl-functionalized CNT were dispersed in 10 mL of ethanol solution together to obtain a mixture. The obtained mixture was ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder was heated at 450 °C for 5 h; after washing, a sample with TiO2 confined inside the CNT tube was obtained, named TiO2-in-CNT;

[0009] (2) Preparation of TiO2-in-CNT / Co3O4: 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole were respectively put into 100 mL of methanol and ultrasonically treated until dispersed. After mixing the two solutions, they were stirred for 5 min. A certain amount of TiO2-in-CNT was added thereto, and after being dispersed evenly, it was left standing for 24 h; after filtration, it was washed 3 times with ethanol and deionized water respectively to obtain a sample; the sample was placed in an oven to be dried; the obtained solid powder after drying was placed in a muffle furnace and heated at a certain temperature for 4 h to obtain the required TiO2-in-CNT / Co3O4.

[0010] Preferably, the amount of the open carboxyl-functionalized CNT in step (1) is 20 - 80 mg.

[0011] Preferably, the amount of TiO2-in-CNT added in step (2) is 100 - 160 mg; the heating temperature of the muffle furnace is 400 - 600 °C.

[0012] Advantages of the present invention:

[0013] 1. The prepared TiO2-in-CNT / Co3O4 catalyst of the present invention can efficiently activate PMS to degrade ECs with visible light.

[0014] 2. The prepared TiO2-in-CNT / Co3O4 catalyst of the present invention has regular morphology, is simple to prepare, has low cost, and is suitable for large-scale popularization and application. Description of the Drawings

[0015] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0016] Figure 1 It is the transmission electron microscope image of the TiO2-in-CNT / Co3O4 catalyst prepared in the specific embodiment 2 of the present invention;

[0017] Figure 2Performance graph of the TiO2-in-CNT / Co3O4 catalyst prepared in Specific Example 2 of the present invention for activating PMS to degrade norfloxacin under visible light. Detailed implementation mode

[0018] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description of the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be construed as a limitation on the protection scope of the present invention.

[0019] Refer to Figure 1 , a preferred embodiment of the present invention, a preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics. The catalyst is a nanocomposite with carbon nanotubes as the main body, TiO2 confined inside the tubes, and Co3O4 loaded outside the tubes. The preparation method of the catalyst includes the following specific steps:

[0020] (1) Preparation of TiO2-in-CNT: Treat CNT with nitric acid by a conventional method to obtain open carboxyl-functionalized CNT. Dissolve 1 mL of TiCl4 uniformly in 10 mL of ethanol to obtain a mixed solution A. Then, disperse 2 mL of the mixed solution A and a certain amount of open carboxyl-functionalized CNT (the amount of open carboxyl-functionalized CNT is 20 - 80 mg) in 10 mL of ethanol solution to obtain a mixture. Ultrasonically disperse the obtained mixture and stir at room temperature to evaporate the solvent. Then, heat the obtained solid powder at 450 °C for 5 h; after washing, obtain a sample with TiO2 confined inside the CNT tubes, named TiO2-in-CNT;

[0021] (2) Preparation of TiO2-in-CNT / Co3O4: Respectively add 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole into 100 mL of methanol, and ultrasonically treat until dispersed. Mix the two solutions and stir for 5 min. Add a certain amount of TiO2-in-CNT (the amount of TiO2-in-CNT is 100 - 160 mg) and disperse evenly, then let it stand for 24 h; after filtration, wash 3 times with ethanol and deionized water respectively to obtain a sample; dry the sample in an oven; place the dried solid powder in a muffle furnace and heat at a certain temperature for 4 h (the heating temperature of the muffle furnace is 400 - 600 °C) to obtain the required TiO2-in-CNT / Co3O4. Specific Example 1

[0023] (1) Preparation of TiO2-in-CNT: Treat CNT with nitric acid using a conventional reported method to obtain open carboxyl-functionalized CNT. A solution is prepared by uniformly dissolving 1 mL of TiCl4 in 10 mL of ethanol to obtain a mixed solution A. Then, 2 mL of the mixed solution A and 20 mg of the above-mentioned open carboxyl-functionalized CNT are dispersed together in 10 mL of an ethanol solution to obtain a mixture. The obtained mixture is ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder is heated at 450 °C for 5 h; after washing, a sample with TiO2 confined inside the CNT tube is obtained, named TiO2-in-CNT;

[0024] (2) Preparation of TiO2-in-CNT / Co3O4: Respectively, 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole are added to 100 mL of methanol, ultrasonically treated until dispersed, the two solutions are mixed and stirred for 5 min, 100 mg of TiO2-in-CNT is added thereto, dispersed evenly and then left standing for 24 h; after filtration, it is washed 3 times with ethanol and deionized water respectively to obtain a sample; the sample is placed in an oven for drying. The obtained solid powder after drying is placed in a muffle furnace and heated at 400 °C for 4 h to obtain the required TiO2-in-CNT / Co3O4. Specific Example 2

[0026] (1) Preparation of TiO2-in-CNT: Treat CNT with nitric acid using a conventional reported method to obtain open carboxyl-functionalized CNT. A solution is prepared by uniformly dissolving 1 mL of TiCl4 in 10 mL of ethanol to obtain a mixed solution A. Then, 2 mL of the mixed solution A and 40 mg of the above-mentioned open carboxyl-functionalized CNT are dispersed together in 10 mL of an ethanol solution to obtain a mixture; the obtained mixture is ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder is heated at 450 °C for 5 h; after washing, a sample with TiO2 confined inside the CNT tube is obtained, named TiO2-in-CNT;

[0027] (2) Preparation of TiO2-in-CNT / Co3O4: Respectively, 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole are added to 100 mL of methanol, ultrasonically treated until dispersed, the two solutions are mixed and stirred for 5 min, 120 mg of TiO2-in-CNT is added thereto, dispersed evenly and then left standing for 24 h; after filtration, it is washed 3 times with ethanol and deionized water respectively to obtain a sample; the sample is placed in an oven for drying, and the obtained solid powder after drying is placed in a muffle furnace and heated at 450 °C for 4 h to obtain the required TiO2-in-CNT / Co3O4.

[0028] Refer to Figure 1 - Figure 2 ,Figure 1 It can be seen that the morphology of the TiO2-in-CNT / Co3O4 catalyst synthesized in Specific Embodiment 2 of the present invention is uniform and regular; Figure 2 This is the performance graph of the TiO2-in-CNT / Co3O4 catalyst prepared in Specific Embodiment 2 of the present invention for photocatalytic activation of PMS to degrade norfloxacin under visible light. Specific Embodiment 3

[0030] (1) Preparation of TiO2-in-CNT: The CNT was treated with nitric acid by a conventional reported method to obtain open carboxyl-functionalized CNT. A solution of 1 mL of TiCl4 uniformly dissolved in 10 mL of ethanol was prepared to obtain a mixed solution A. Then, 2 mL of the mixed solution A and 60 mg of the above-mentioned open carboxyl-functionalized CNT were dispersed in 10 mL of ethanol solution together to obtain a mixture. The obtained mixture was ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder was heated at 450 °C for 5 h; after washing, a sample with TiO2 confined in the CNT tube was obtained, named TiO2-in-CNT;

[0031] (2) Preparation of TiO2-in-CNT / Co3O4: 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole were respectively put into 100 mL of methanol, and ultrasonic treatment was carried out until dispersion. After the two solutions were mixed, they were stirred for 5 min. Then, 140 mg of TiO2-in-CNT was added and dispersed evenly, and then left standing for 24 h; after filtration, it was washed 3 times with ethanol and deionized water respectively to obtain a sample; the sample was placed in an oven for drying; the obtained solid powder after drying was placed in a muffle furnace and heated at 500 °C for 4 h to obtain the required product. Specific Embodiment 4

[0033] (1) Preparation of TiO2-in-CNT: The CNT was treated with nitric acid by a conventional reported method to obtain open carboxyl-functionalized CNT. A solution of 1 mL of TiCl4 uniformly dissolved in 10 mL of ethanol was prepared to obtain a mixed solution A. Then, 2 mL of the mixed solution A and 60 mg of the above-mentioned open carboxyl-functionalized CNT were dispersed in 10 mL of ethanol solution together to obtain a mixture. The obtained mixture was ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder was heated at 450 °C for 5 h; after washing, a sample with TiO2 confined in the CNT tube was obtained, named TiO2-in-CNT;

[0034] (2) Preparation of TiO2-in-CNT / Co3O4: 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole were respectively put into 100 mL of methanol, and ultrasonic treatment was carried out until dispersion. After mixing the two solutions, stirring was carried out for 5 min. Then, 140 mg of TiO2-in-CNT was added thereto, and after uniform dispersion, it was left standing for 24 h; after filtration, it was washed 3 times with ethanol and deionized water respectively to obtain the sample; the sample was placed in an oven for drying. The obtained solid powder after drying was placed in a muffle furnace and heated at 500 °C for 4 h to obtain the required TiO2-in-CNT / Co3O4.

[0035] The TiO2-in-CNT / Co3O4 catalyst prepared by the present invention can efficiently activate PMS to degrade ECs with visible light. The TiO2-in-CNT / Co3O4 catalyst prepared by the present invention has regular morphology, simple preparation, low cost, and is suitable for large-scale popularization and application.

[0036] On the premise of no conflict, those skilled in the art can freely combine and superimpose the above additional technical features.

[0037] The above are only the preferred embodiments of the present invention, and all technical solutions that achieve the purpose of the present invention by basically the same means fall within the protection scope of the present invention.

Claims

1. A preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics, characterized in that: The catalyst is a nanocomposite with carbon nanotubes as the main body, TiO2 embedded in the tubes, and Co3O4 loaded on the outer surface. The preparation method of the catalyst includes the following specific steps: (1) Preparation of TiO2-in-CNT: The CNTs are treated with nitric acid by a conventional method to obtain open carboxyl-functionalized CNTs. 1 mL of TiCl4 is uniformly dissolved in 10 mL of ethanol to obtain a mixed solution A. Then, 2 mL of the mixed solution A and a certain amount of open carboxyl-functionalized CNTs are dispersed together in 10 mL of an ethanol solution to obtain a mixture. The obtained mixture is ultrasonically dispersed and then stirred at room temperature to evaporate the solvent. Then, the obtained solid powder is heated at 450 °C for 5 h; after washing, a sample with TiO2 confined inside the CNT tubes is obtained, named TiO2-in-CNT; (2) Preparation of TiO2-in-CNT / Co3O4: 1.452 g of Co(NO3)2·6H2O and 1.64 g of 2-methylimidazole are respectively added to 100 mL of methanol, and ultrasonically treated until dispersed. After the two solutions are mixed, they are stirred for 5 min. A certain amount of TiO2-in-CNT is added thereto, dispersed evenly, and then left standing for 24 h; after filtration, it is washed 3 times with ethanol and deionized water respectively to obtain a sample; the sample is placed in an oven to be dried; the solid powder obtained after drying is placed in a muffle furnace and heated at a certain temperature for 4 h to obtain the required TiO2-in-CNT / Co3O4.

2. The preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics according to claim 1, characterized in that: In step (1), the amount of the open carboxyl-functionalized CNTs is 20 - 80 mg.

3. The preparation method of a TiO2-in-CNT / Co3O4 catalyst for photocatalytic activation of PMS to degrade antibiotics according to claim 1, characterized in that: In step (2), the amount of TiO2-in-CNT added is 100 - 160 mg; the heating temperature of the muffle furnace is 400 - 600 °C.

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