Nano-carbon supported ruthenium cluster nano-catalyst as well as preparation method and application thereof

Abstract

The invention discloses a nano-carbon supported ruthenium cluster nano-catalyst as well as a preparation method and application thereof. According to the present invention, the synthesis process of the catalyst is simple and easy to perform, the reaction process is controllable, the nanocarbon with characteristics of rich defects and large specific surface area is adopted as the carrier, the ruthenium cluster is loaded on the surface of the nanocarbon, and the nanometer catalyst with characteristics of high specific surface area and high atom utilization rate is synthesized. The catalyst can catalyze persulfate (PDS) to generate products with strong oxidation activity, namely sulfate free radicals (SO4.-), hydroxyl free radicals (. OH) and singlet oxygen (1O2), so that effective inactivation of bacteria is realized. In the invention, the reaction of activating the persulfate to disinfect by the catalyst is carried out at room temperature under neutral conditions, and in a mild reaction environment, the nanocarbon-loaded ruthenium cluster nanocatalyst shows good capability of catalyzing the persulfate to inactivate bacteria, and has huge potential in practical application of water disinfection.

Description

Technical Field

[0001] The invention belongs to the technical field of catalytic persulfate disinfection, and specifically relates to a nano-carbon-loaded ruthenium cluster nano-catalyst and a preparation method and application thereof. Background Art

[0002] Water is the source of life. The pollution of water resources by pathogens seriously harms the ecological environment and human health. People are paying more and more attention to the safety of water resources. At present, waterborne diseases have brought great harm to the human body. Pathogenic microorganisms in water such as pathogenic bacteria and viruses are the main factors causing waterborne diseases. How to effectively solve the problem of pathogenic microorganisms in water has become an important research topic at present. Traditional water disinfection methods include ultraviolet radiation, chlorination, ozone oxidation, etc. These methods have problems such as insufficient disinfection, high energy consumption, and great impact of by-products on the environment. At present, advanced oxidation process (AOPs) is a more advanced disinfection technology, and the Fenton-like advanced oxidation process based on persulfate is one of the typical representatives.

[0003] The Fenton-like advanced oxidation process based on persulfate has the advantages of more efficient sterilization, lower energy consumption, and simple operation. After being activated, persulfate can produce sulfate free radicals (SO4 ·- ), hydroxyl radical (·OH), and singlet oxygen ( 1 O2) and other types of products with strong oxidizing properties. These species with strong oxidizing properties can inactivate bacteria in a variety of ways, including attacking bacterial cell membranes, changing the structure of their macromolecules and cell membrane permeability, causing the outflow of cell contents, and oxidizing bacterial proteins, causing oxidative damage to bacterial DNA and RNA, and then leading to bacterial death. In summary, activated persulfate has great development potential in the field of water disinfection. Summary of the invention

[0004] The purpose of the present invention is to develop a nano-carbon-supported ruthenium cluster nanocatalyst that can efficiently catalyze persulfate and effectively inactivate bacteria. The catalyst can be applied to the field of bacterial inactivation in water bodies, and the catalyst can achieve the purpose of effective disinfection by activating persulfate to produce a product with strong oxidizing properties.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The invention discloses a nano-carbon supported ruthenium cluster nano-catalyst, which is synthesized by taking nano-carbon as a carrier and atomically dispersed ruthenium clusters as active centers.

[0007] Preferably, in the above-mentioned nanocarbon-supported ruthenium cluster nanocatalyst, the loading amount of metal ruthenium is 0.5% by mass.

[0008] The preparation method of the nano-carbon supported ruthenium cluster nanocatalyst described in any of the above items comprises the following steps: dispersing ruthenium chloride in deionized water, dispersing the nano-diamond@graphene composite material in deionized water, obtaining a uniform suspension by ultrasonic dispersion, adjusting the pH of the system to 10 with sodium carbonate, maintaining stirring at 50°C for 8 hours, filtering, washing with deionized water, and drying in an oven at 60°C to obtain a precursor, and reducing the precursor to obtain the nano-carbon supported ruthenium cluster nanocatalyst.

[0009] Furthermore, in the above-mentioned preparation method, the method of reducing the precursor is as follows: the obtained precursor is reduced at 200° C. for 1 hour under H 2 atmosphere to obtain a nanocarbon-supported ruthenium cluster nanocatalyst.

[0010] Use of any of the above-mentioned nanocarbon-supported ruthenium cluster nanocatalysts in catalyzing the inactivation of bacteria by persulfate.

[0011] Furthermore, the above application is carried out in the following method: adding nanocarbon-supported ruthenium cluster nanocatalyst and persulfate to the bacterial suspension.

[0012] Preferably, in the above application, the concentration of the nanocarbon-supported ruthenium cluster nanocatalyst is 0.06 mg / mL.

[0013] Preferably, in the above application, the concentration of the persulfate is 2 mM.

[0014] Furthermore, in the above application, the bacteria is Escherichia coli.

[0015] Furthermore, in the above application, the persulfate is potassium persulfate.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The present invention prepares nanocarbon-supported ruthenium cluster nanocatalysts, the preparation method is simple and easy, the reaction process is controllable, and the conditions for large-scale production are met.

[0018] 2. In the present invention, defect-rich nanocarbon with a large specific surface area is used as a carrier. The defect-rich carrier can effectively anchor and stabilize atomically dispersed metals, improve the stability of the catalyst, and the large specific surface area helps to capture bacteria, which is an important contribution to the effective inactivation of bacteria by the material. The prepared nanocarbon-loaded ruthenium cluster nanocatalyst can catalyze persulfate to effectively inactivate Escherichia coli.

[0019] 3. In the present invention, metallic ruthenium is loaded on the nanocarbon carrier in the form of clusters. The atomic-level dispersion can greatly improve the utilization rate of metal atoms, and the clusters provide adjacent active sites, further improving the catalytic ability of the material.

[0020] 4. The reaction of activating persulfate to inactivate bacteria by the nanocarbon-supported ruthenium cluster nanocatalyst prepared by the present invention can be carried out at room temperature and under neutral conditions. In a mild reaction environment, the catalyst exhibits a good ability to catalyze persulfate to inactivate bacteria and can effectively inactivate Escherichia coli.

[0021] 5. The active substances produced by the nanocarbon-supported ruthenium cluster nanocatalyst prepared by the present invention catalyze the production of persulfate contain a large amount of 1 O2, 1 O2 has the unique advantage of non-radical oxidation, is less affected by environmental factors, and can be applied in more scenarios.

[0022] 6. The nanocarbon-loaded ruthenium cluster nanocatalyst prepared by the present invention can efficiently activate persulfate and effectively inactivate Escherichia coli, and the active substances produced are mainly 1 O2, relying on its unique advantage of non-radical oxidation, can be applied to a variety of environmental conditions and is expected to be used for bacterial inactivation in actual water bodies.

[0023] In summary, the nanocarbon-supported ruthenium cluster nanocatalyst of the present invention is prepared in a simple and easy manner, has the advantages of a carrier rich in defects and a high specific surface area, and an active site advantage with high atomic utilization, and the active substance produced contains a large amount of 1 O2, less affected by the environment. The combined effect of various factors makes it a catalyst with excellent catalytic performance, which can effectively deactivate 10 7 coli with a CFU / mL, which has great potential in the practical application of inactivating water bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the HRTEM image of nanodiamond@graphene (ND@G).

[0025] Figure 2 It is a nanocarbon-supported ruthenium cluster nanocatalyst (Ru n / ND@G), where A: 5 nm; B: 2 nm.

[0026] Figure 3 The carrier nanodiamond@graphene (ND@G) and nanocarbon-supported ruthenium cluster nanocatalyst (Ru n / ND@G)’s X-ray diffraction pattern (XRD pattern).

[0027] Figure 4 It is ND@G+PDS, Ru n / ND@G、PDS、Ru n / Diagram of ND@G+PDS inactivating Escherichia coli.

[0028] Figure 5 is the Ru under different PDS concentrations n / Diagram of ND@G+PDS inactivating Escherichia coli.

[0029] Figure 6 It is different n / ND@G concentration of Ru n / Diagram of ND@G+PDS inactivating Escherichia coli.

[0030] Figure 7 Ru under the action of different scavengers (tert-butyl alcohol TBA, furfuryl alcohol FFA, methanol) n / Diagram of the inactivation of Escherichia coli by the ND@G+PDS system. DETAILED DESCRIPTION

[0031] The invention is further described in detail below in conjunction with specific embodiments.

[0032] Example 1 Nanocarbon-supported Ruthenium Cluster Nanocatalyst (Ru n / ND@G)

[0033] (I) Preparation of materials

[0034] First, add 40mL of deionized water to a round-bottom flask, then add 50μL of ruthenium trichloride solution with a metal Ru concentration of 10mg / mL to the round-bottom flask, weigh 100mg of nanodiamond@graphene (ND@G) and add it to the round-bottom flask (the metal and the carrier are added at a mass percentage of 0.5%), and ultrasonically disperse for 20 minutes to form a uniform suspension in the round-bottom flask. Add sodium carbonate solution to adjust the pH of the suspension to 10. Increase the temperature of the oil bath to 50°C, then place the round-bottom flask in the oil bath and stir at this temperature for 8h. Finally, cool the reaction solution and filter it, wash it with deionized water several times, and then dry it at 60°C to obtain a precursor. Hydrogen is provided by a hydrogen generator, and the prepared precursor is placed in a tubular furnace and reduced at 200°C for 1 hour in a hydrogen atmosphere to obtain a nanocarbon-supported ruthenium cluster nanocatalyst (Ru n / ND@G).

[0035] (II) Characterization

[0036] Figure 1 This is the HRTEM image of the carrier ND@G, from which the morphology of the carrier can be clearly observed.

[0037] Figure 2 As catalyst Ru nAC-HAADF-STEM image of / ND@G. It can be seen from the image that the ruthenium species are uniformly loaded on the surface of the carrier in the form of clusters.

[0038] Figure 3 As the carrier ND@G and catalyst Ru n / ND@G XRD pattern, it can be seen from the figure that ND@G and Ru n / ND@G have typical characteristic signals of diamond and graphene, indicating that the loading of Ru does not destroy the structure of the carrier, and Ru n There is no characteristic signal of Ru in / ND@G, indicating that Ru is highly dispersed on the carrier surface.

[0039] Example 2 Nanocarbon-supported Ruthenium Cluster Nanocatalyst (Ru n Study on the disinfection performance of / ND@G)

[0040] The disinfection experiment includes the following steps:

[0041] 1) LB liquid medium: Add 2 g of tryptone, 2 g of sodium chloride and 1 g of yeast extract powder to a 250 mL conical flask, then add 200 mL of deionized water to the conical flask, adjust the pH to 7.2-7.4, and sterilize at high temperature and high pressure for later use.

[0042] 2) LB solid medium: Add 16.5 g of LB nutrient agar to a 500 mL conical flask, then add 500 mL of water to the conical flask, adjust the pH to 7.2-7.4, sterilize with high temperature and high pressure, shake well, pour into a culture dish (sterilized) while hot, cool and refrigerate for later use.

[0043] 3) Sterilization: Before the experiment, the culture medium, inoculation loop, applicator, centrifuge tube, pipette tip, beaker, deionized water and other items involved in the experiment need to be sterilized. Sterilization equipment: pressure steam sterilizer, setting parameters: 121℃, 20min.

[0044] 4) Bacterial culture: After thawing the Escherichia coli strain (E.coli ATCC 15597), use an inoculation loop to streak the strain on the solid culture medium, place the solid culture medium in an incubator, set the temperature to 37°C, and culture for 12 hours. Add 10mL of liquid culture medium to a conical flask, use an inoculation loop to pick up a single colony on the solid culture medium and place it in the liquid culture medium, put it in a shaker, set the parameters to: 37°C, 200r, and culture for 10 hours to obtain a bacterial suspension. Take 5mL of the bacterial suspension and centrifuge it at 9000r / min for 5 minutes in a centrifuge. After washing twice, add 5mL of deionized water to obtain a concentration of about 10 9 CFU / mL of Escherichia coli suspension, and then dilute the suspension 10 times to obtain a concentration of 10 8CFU / mL of Escherichia coli suspension is ready for use.

[0045] 5) Disinfection experiment: This experiment uses E. coli as the research object, and the concentration of E. coli is 10 7 CFU / mL. Add deionized water and bacteria to a beaker, place it on a magnetic stirrer and stir, adjust the pH of the system to between 6.5 and 7 with sodium hydroxide and sulfuric acid, add a certain concentration of PDS potassium persulfate and catalyst and start timing, take out 1mL of the reaction solution at regular intervals and add it to a centrifuge tube containing sodium thiosulfate, take 100μL of the reaction solution after appropriate dilution and spread it on the solid culture medium, place the solid culture medium in a constant temperature incubator at 37℃ and culture for 12h, and calculate the bacterial concentration in the reaction solution during this period by the number of colonies and the dilution multiple. The volume of the reaction solution in the experiment was 100mL, and the optimal concentration of potassium persulfate was found to be 2mM and the catalyst concentration was 0.06mg / mL.

[0046] Figure 4 For Ru n / ND@G+PDS、Ru n / ND@G, PDS and ND@G+PDS inactivate Escherichia coli. The experimental results show that Ru alone n The inactivation effects of E. coli by ND@G, PDS or carrier ND@G+PDS were all negligible. n / ND@G can catalyze persulfate to inactivate Escherichia coli within 75 minutes, and the system has a good disinfection effect.

[0047] Figure 5 is Ru at different PDS concentrations n / ND@G+PDS inactivation of Escherichia coli. The experimental results show that the disinfection ability of the system increases with the increase of PDS concentration, and the optimal PDS concentration is 2mM.

[0048] Figure 6 For different n / ND@G concentration of Ru n / ND@G+PDS inactivation of Escherichia coli. Experimental results show that with the increase of Ru n / ND@G concentration increases with the disinfection ability of the system, and the optimal Ru n / ND@G concentration is 0.06 mg / mL.

[0049] 6) Active substance test: Different scavengers are added to the disinfection experiment to verify the active substances produced in the system. TBA is a scavenger of ·OH, and FFA is 1 O2 scavenger, Methanol is SO4 ·-In the disinfection experiment, different scavengers were added to observe the inactivation of E. coli in the system to determine the active substances in the system that act on E. coli. The concentration of potassium persulfate was 2mM, the catalyst concentration was 0.06mg / mL, and the concentration of E. coli was 10 7 CFU / mL.

[0050] Figure 7 Ru under different scavengers n / ND@G+PDS system inactivates E. coli. The experimental results show that the disinfection ability of the system is inhibited after the addition of TBA, indicating that ·OH is produced in the system. Compared with the addition of TBA, the disinfection ability of the system is further weakened after the addition of methanol, indicating that in addition to ·OH, SO4 is also produced in the system. ·- After adding FFA, the disinfection ability of the system was also inhibited, indicating that 1 O2. In summary, the active substances that act on inactivating E. coli mainly include 1 O2, OH and SO4 ·- .

Claims

1. A nanocarbon-supported ruthenium cluster nanocatalyst, characterized in that: The nano-carbon-supported ruthenium cluster nanocatalyst is synthesized with nano-carbon as carrier and atomically dispersed ruthenium clusters as active centers.

2. The nanocarbon-supported ruthenium cluster nanocatalyst according to claim 1, characterized in that: In terms of mass percentage, the loading amount of metal ruthenium is 0.5%.

3. The method for preparing a nanocarbon-supported ruthenium cluster nanocatalyst according to claim 1 or 2, characterized in that: The method comprises the following steps: dispersing ruthenium chloride in deionized water, dispersing a nano-diamond@graphene composite material in deionized water, obtaining a uniform suspension by ultrasonic dispersion, adjusting the pH value of the system to 10 with sodium carbonate, maintaining stirring at 50° C. for 8 hours, filtering, washing with deionized water, and drying in an oven at 60° C. to obtain a precursor, and reducing the precursor to obtain a nano-carbon-loaded ruthenium cluster nano-catalyst.

4. The preparation method according to claim 3, characterized in that: The method for reducing the precursor is as follows: the obtained precursor is reduced at 200° C. for 1 hour under H2 atmosphere to obtain a nano-carbon-supported ruthenium cluster nano-catalyst.

5. Use of the nanocarbon-supported ruthenium cluster nanocatalyst according to claim 1 or 2 in catalyzing the inactivation of bacteria by persulfate.

6. The use according to claim 5, characterized in that: The method is as follows: adding nanocarbon-supported ruthenium cluster nanocatalyst and persulfate to a bacterial suspension.

7. The use according to claim 6, characterized in that: The concentration of the nano-carbon-supported ruthenium cluster nanocatalyst is 0.06 mg / mL.

8. The use according to claim 6, characterized in that: The concentration of persulfate was 2 mM.

9. The use according to claim 5, characterized in that: The bacteria is Escherichia coli.

10. The use according to claim 5, characterized in that: The persulfate is potassium persulfate.

Images