A catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, and its preparation method and application

Abstract

The present invention provides a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, and a preparation method and application thereof. The preparation method of the present invention comprises the following steps: S1: Dissolve vanadyl acetylacetonate and 2-methylimidazole in an organic solvent, then add zinc nitrate and carry out a polymerization reaction under alkaline conditions. After the reaction, filter, wash, and dry to obtain an intermediate; S2: Grind the intermediate and then calcine it, and after grinding, washing, and drying again, obtain a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure. The catalyst of the present invention can activate dissolved oxygen to degrade pollutants at normal temperature and pressure and within a relatively wide pH range, without the need for external energy and additives. The catalyst has a long service life and good stability during the degradation of pollutants, greatly reducing the treatment cost of new pollutants in water.

Description

Technical Field

[0001] The present invention relates to the technical field of treatment of new pollutants in water, and particularly to a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, and a preparation method and application thereof. Background Art

[0002] With the rapid development of industry and human society, the discharge of sewage has been increasing continuously. Sewage contains harmful substances such as organic matters, inorganic salts, sulfides, nitrides, and various heavy metals, causing great pollution to the environment.

[0003] Currently, the methods for treating new pollutants in water by sewage treatment plants include adsorption using activated sludge and membrane bioreactor technology combined with traditional activated sludge method, etc. However, after treating sewage containing POPs by the above methods, new pollutants can still be detected in the effluent. Since the traditional sewage treatment process is difficult to adapt to the current water pollution situation, it is necessary to conduct research on the advanced treatment of new water pollutants.

[0004] Based on this, advanced oxidation technologies (AOPs) that can generate strongly oxidizing active species for the tertiary advanced treatment of sewage have gradually developed. However, traditional advanced oxidation technologies have defects such as high pH range requirements, small selectivity, easy generation of iron sludge, high treatment costs, and the need to continuously add chemicals. Therefore, it is necessary to develop a water treatment technology that does not require additional energy and chemicals and is efficient, low-energy-consuming, and clean.

[0005] In view of this, the present invention is specifically proposed. Summary of the Invention

[0006] The object of the present invention is to provide a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, and a preparation method and application thereof. The catalyst can activate dissolved oxygen to degrade pollutants at normal temperature, normal pressure, and within a wide pH range, without the need for external energy and additives, has a long service life of the catalyst, and good stability when degrading pollutants.

[0007] The present invention provides a preparation method of a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, comprising the following steps:

[0008] S1: Dissolve vanadyl acetylacetonate and 2-methylimidazole in an organic solvent, then add zinc nitrate and carry out a polymerization reaction under alkaline conditions. After the reaction, filter, wash, and dry to obtain an intermediate;

[0009] S2: Grind the intermediate and then calcine it. After grinding, washing, and drying again, obtain a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure.

[0010] In step S1, the molar ratio of vanadyl acetylacetonate, 2-methylimidazole, and zinc nitrate is (1-10):(10-50):(1-10), preferably (1-5):(10-50):(1-5), more preferably (2-4):(28-32):(1-3), and even more preferably 3:30:2.

[0011] In step S1, the organic solvent is selected from at least one of methanol, ethanol, and isopropanol.

[0012] In step S1, the alkaline condition is a pH value of 10-12; the temperature of the polymerization reaction is 20-40 °C, and the time of the polymerization reaction is 20-30 h.

[0013] In step S1, the filtration is centrifugal filtration, the rotation speed during centrifugal filtration is 7000-10000 rpm, and the centrifugal filtration time is 5-10 min; the washing is carried out with ethanol, and the number of washing times is 3-10 times; the drying can be carried out in a vacuum drying oven; the drying temperature is 60-80 °C, and the drying time is 6-10 h.

[0014] In step S2, the calcination is carried out in a tubular furnace under a nitrogen atmosphere, the calcination temperature is 500-800 °C, preferably 600-800 °C, more preferably 700 °C; the calcination time is 1-3 h, and the heating rate during calcination is 5-10 °C / min.

[0015] In step S2, it is ground to 50-100 mesh; the washing is carried out with ethanol, and the number of washing times is 3-10 times; the drying temperature is 60-80 °C, and the drying time is 3-5 h.

[0016] The present invention also provides a catalyst for activating dissolved oxygen at normal temperature and pressure to degrade pollutants, which is prepared according to the above preparation method.

[0017] The present invention also provides the application of the above catalyst for activating dissolved oxygen at normal temperature and pressure to degrade pollutants in treating new pollutants in water.

[0018] The present invention does not strictly limit the type of new pollutants. The new pollutants include but are not limited to rhodamine B, ciprofloxacin, bisphenol A, phenytoin, etc.; the concentration of new pollutants in water ≥ 10 ppm; the dosage of the catalyst in treating new pollutants in water is 0.6-1.4 g / L.

[0019] The implementation of the present invention has at least the following advantages:

[0020] 1. The catalyst of the present invention can activate the dissolved oxygen in water at normal temperature and pressure, utilize the energy of pollutants in sewage, form a catalyst-dissolved oxygen in water self-purification system in sewage. During the process of removing organic pollutants in water, no additional energy and chemicals need to be added, and no secondary pollution will be generated, greatly reducing energy consumption and improving treatment efficiency.

[0021] 2. The surface of the catalyst of the present invention is rough and uneven, covered with wrinkles. When treating organic pollutants in sewage, it can adapt to a relatively wide pH range and has strong applicability.

[0022] 3. The catalyst of the present invention is a solid catalyst, which is easy to recycle. In particular, the catalyst has a long service life and good stability during pollutant degradation, greatly reducing the treatment cost of new pollutants in water and having good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 Scanning electron microscope image of the catalyst prepared in Example 1;

[0025] Figure 2 Degradation curves of the catalyst prepared in Example 1 for Rhodamine B (RhB), Bisphenol A (BPA), and Ciprofloxacin (CIP);

[0026] Figure 3 Degradation curves of the catalyst prepared in Example 1 for Ciprofloxacin (CIP) under different pH conditions;

[0027] Figure 4 Structural schematic diagram of a fixed-bed column reactor using the catalyst of the present invention;

[0028] Figure 5 Effect diagram of the continuous degradation of Rhodamine B (RhB) by the catalyst prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations for the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Example 1

[0033] The preparation method of the catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure in this example includes the following steps:

[0034] S1: Prepare the intermediate

[0035] Dissolve vanadium acetylacetonate and 2-methylimidazole in ethanol, then add zinc nitrate, adjust the pH to 10 and carry out a polymerization reaction, wherein the molar ratio of vanadium acetylacetonate, 2-methylimidazole, and zinc nitrate is controlled to be 3:30:2, the dosage ratio of vanadium acetylacetonate to ethanol is 3 mol:300 mL, the polymerization reaction temperature is 30 °C, and the polymerization reaction time is 24 h.

[0036] After the polymerization reaction, centrifuge the reaction product at 8000 rpm for 10 min, then wash it 6 times with ethanol, and then vacuum dry it at 60 °C for 12 h to obtain the intermediate.

[0037] S2: Prepare the catalyst

[0038] Grind the intermediate obtained in step S1 to pass through a 50-mesh sieve, and then calcine it in a nitrogen atmosphere using a tube furnace. When calcining, heat it from room temperature to 700 °C at a heating rate of 8 °C / min, and then calcine it at 700 °C for 1 h; after calcining, grind it again to pass through a 50-mesh sieve, wash it 6 times with ethanol, and then vacuum dry it at 60 °C for 5 h to obtain the catalyst (V-Zn@GN) for degrading pollutants by activating dissolved oxygen at normal temperature and pressure. Its scanning electron micrograph is as Figure 1 shown.

[0039] Example 2

[0040] The preparation method of the catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure in this example includes the following steps:

[0041] S1: Prepare the intermediate

[0042] Vanadium acetylacetonate and 2-methylimidazole are dissolved in ethanol, and then zinc nitrate is added. After adjusting the pH to 11, a polymerization reaction is carried out. The molar ratio of vanadium acetylacetonate, 2-methylimidazole, and zinc nitrate is controlled to be 2:28:3, the dosage ratio of vanadium acetylacetonate to ethanol is 2 mol:200 mL, the polymerization reaction temperature is 20 °C, and the polymerization reaction time is 30 h.

[0043] After the polymerization reaction, the reaction product is centrifuged at 10000 rpm for 5 min, then washed with ethanol 3 times, and then vacuum dried at 70 °C for 11 h to obtain an intermediate.

[0044] S2: Preparation of catalyst

[0045] The intermediate in step S1 is ground to pass through a 60-mesh sieve, and then calcined in a tubular furnace under a nitrogen atmosphere. During calcination, the temperature is raised from room temperature to 600 °C at a heating rate of 5 °C / min, and then calcined at 600 °C for 3 h; after calcination, it is ground again to pass through a 60-mesh sieve, washed with ethanol 3 times, and then vacuum dried at 70 °C for 4 h to obtain a catalyst (V-Zn@GN) for degrading pollutants by activating dissolved oxygen at normal temperature and pressure.

[0046] Example 3

[0047] The preparation method of the catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure in this example includes the following steps:

[0048] S1: Preparation of intermediate

[0049] Vanadium acetylacetonate and 2-methylimidazole are dissolved in ethanol, and then zinc nitrate is added. After adjusting the pH to 12, a polymerization reaction is carried out. The molar ratio of vanadium acetylacetonate, 2-methylimidazole, and zinc nitrate is controlled to be 4:32:1, the dosage ratio of vanadium acetylacetonate to ethanol is 4 mol:400 mL, the polymerization reaction temperature is 40 °C, and the polymerization reaction time is 20 h.

[0050] After the polymerization reaction, the reaction product is centrifuged at 7000 rpm for 10 min, then washed with ethanol 10 times, and then vacuum dried at 80 °C for 10 h to obtain an intermediate.

[0051] S2: Preparation of catalyst

[0052] The intermediate in step S1 is ground to pass through a 60-mesh sieve, and then calcined in a tubular furnace under a nitrogen atmosphere. During calcination, the temperature is raised from room temperature to 800 °C at a heating rate of 10 °C / min, and then calcined at 800 °C for 2 h; after calcination, it is ground again to pass through a 60-mesh sieve, washed with ethanol 10 times, and then vacuum dried at 80 °C for 3 h to obtain a catalyst (V-Zn@GN) for degrading pollutants by activating dissolved oxygen at normal temperature and pressure.

[0053] Test Example 1

[0054] The catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure prepared in Example 1 was used to degrade organic pollutants in water; the specific steps were as follows:

[0055] 0.05 g of the catalyst (V-Zn@GN) in Example 1 was added to a 50 mL, 10 ppm pollutant solution, and the temperature was kept constant at 35°C with continuous stirring. Samples were taken at different time points to detect the concentration change of the pollutants; the results are as Figure 2 shown.

[0056] Figure 2 The results showed that within 15 minutes, the degradation efficiency of the catalyst (V-Zn@GN) for RhB and CIP reached about 99%, and the degradation efficiency for BPA reached about 80% within 60 minutes.

[0057] Test Example 2

[0058] The catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure prepared in Example 1 was used to degrade organic pollutants in water; the specific steps were as follows:

[0059] 0.05 g of the catalyst (V-Zn@GN) in Example 1 was added to a 50 mL, 10 ppm pollutant solution, and the pH values of the pollutant solution were adjusted to 3.23, 5.14, 7.52, and 10.85 respectively. The temperature was kept constant at 35°C with continuous stirring. Samples were taken at different time points to detect the concentration change of the pollutants; the results are as Figure 3 shown.

[0060] Figure 3 The results showed that within 45 minutes, the degradation efficiency of the catalyst (V-Zn@GN) for CIP reached about 99% in most pH environments.

[0061] Test Example 3

[0062] The catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure prepared in Example 1 was used to degrade the organic pollutant CIP in water; the specific steps were as follows:

[0063] Combined with Figure 4 shown, the catalyst (V-Zn@GN) in Example 1 and the pollutant (RhB) solution formed a self-purification system in a fixed-bed column reactor (the catalyst concentration was 1.0 g / L, and the pollutant concentration was 10 ppm). It was continuously operated under natural conditions, the hydraulic retention time was 30 minutes, and the sampling time interval was 12 hours. The initial concentration and the concentration after the reaction of the pollutant (RhB) were detected to determine the stability and reproducibility of the catalyst; the results are as Figure 5 shown.

[0064] Figure 5 The results show that: after continuous operation for 168 hours, the degradation efficiency of the catalyst (V-Zn@GN) for the pollutant (RhB) reaches about 99%, indicating that the catalyst (V-Zn@GN) of the present invention has good stability and can be applied to the treatment of actual wastewater.

[0065] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, characterized in that, It includes the following steps: S1: Dissolve vanadyl acetylacetonate and 2-methylimidazole in an organic solvent, then add zinc nitrate and carry out a polymerization reaction under alkaline conditions. After the reaction, filter, wash, and dry to obtain an intermediate; S2: Grind the intermediate and then calcine it. After grinding, washing, and drying again, obtain a catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure; In step S1, the molar ratio of vanadyl acetylacetonate, 2-methylimidazole, and zinc nitrate is (1-10):(10-50):(1-10); the alkaline condition is a pH value of 10-12; the temperature of the polymerization reaction is 20-40 °C, and the time of the polymerization reaction is 20-30 h; In step S2, the calcination is carried out in a tubular furnace under a nitrogen atmosphere. The calcination temperature is 500-800 °C, the calcination time is 1-3 h, and the heating rate during calcination is 5-10 °C / min.

2. The preparation method according to claim 1, characterized in that, In step S1, the organic solvent is selected from at least one of methanol, ethanol, and isopropanol.

3. The preparation method according to claim 1, wherein In step S1, the filtration is centrifugal filtration. The rotation speed during centrifugal filtration is 7000-10000 rpm, and the centrifugal filtration time is 5-10 min; the washing is carried out with ethanol, and the number of washing times is 3-10 times; the drying temperature is 60-80 °C, and the drying time is 6-10 h.

4. The preparation method according to claim 1, characterized in that, In step S2, grind to 50-100 mesh; the washing is carried out with ethanol, and the number of washing times is 3-10 times; the drying temperature is 60-80 °C, and the drying time is 3-5 h.

5. A catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure, characterized in that, Prepared according to the preparation method described in any one of claims 1-4.

6. Application of the catalyst for degrading pollutants by activating dissolved oxygen at normal temperature and pressure according to claim 5 in treating water pollutants.

7. The application according to claim 6, wherein The pollutants include at least one of rhodamine B, ciprofloxacin, bisphenol A, and phenytoin.

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