A ruthenium-poly-2,6-diaminopyridine catalytic material, a preparation method and application thereof

Abstract

The application provides a ruthenium-poly-2,6-diaminopyridine (Ru-PDAP) catalytic material and a preparation method and application thereof, and belongs to the technical field of water treatment. The Ru-PDAP catalytic material provided by the application comprises porous poly-2,6-diaminopyridine (PDAP) and ruthenium nanoparticles (Ru) loaded on the surface and internal pores of the PDAP. The Ru-PDAP catalytic material provided by the application has a good cavity structure, the PDAP serves as an electron donor to provide an activation site for a periodate, and the mutual conversion of various valence states (0, 2+, 3+, 4+, 6+, 8+) of the Ru can provide more electrons for the oxidation and degradation of organic matters by the periodate, and has a good catalytic effect on the degradation of antibiotics by the periodate / hydrogen peroxide.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a ruthenium-poly 2,6-diaminopyridine catalytic material, a preparation method and an application thereof. Background Art

[0002] The extensive use of antibiotics has caused them to proliferate in the aquatic environment and has led to the proliferation of a large number of drug-resistant microorganisms, which has led to the aggravation of antibiotic and microbial pollution in the aquatic environment.

[0003] At present, the main methods for removing antibiotic pollutants in water bodies include physical membrane treatment, adsorption and oxidation methods. Studies have shown that the use of catalysts (or activators) can effectively improve the removal effect of antibiotic pollutants. For example, patent CN114671510A discloses a method for using Fe-N self-doped algae-based carbon catalyst to activate persulfate to degrade antibiotics. The Fe-N self-doped algae-based carbon catalyst is used as a catalyst for activating persulfate to degrade antibiotics. It can effectively activate persulfate and convert it into active groups with strong oxidizing effects on antibiotics, so that these active groups can be used to achieve effective degradation of antibiotics; patent CN115430444A discloses a method for degrading macrolide antibiotic wastewater by using MXenes / NZVI catalyst to synergistically photoactivate persulfate. The method uses MXenes / NZVI catalyst to add MXenes / NZVI catalyst to wastewater containing macrolide antibiotics. MXenes / NZVI synergistically photoactivates persulfate to produce OH radicals and SO4 ·- Free radicals can act on the glycosidic bond connecting the lactone ring and the sugar group of macrolide antibiotics, thereby achieving the effect of degrading antibiotics.

[0004] However, there is no research or report on the relevant catalysts (or activators) for the periodate (PI) / hydrogen peroxide (H2O2) system for antibiotic degradation. Summary of the Invention

[0005] In view of this, the present invention aims to provide a ruthenium-poly (2,6-diaminopyridine) (Ru-PDAP) catalytic material, its preparation method, and its application. The Ru-PDAP catalytic material of the present invention can significantly improve the ability of the PI / H2O2 system to degrade antibiotics.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The invention provides a ruthenium-poly 2,6-diaminopyridine catalytic material, comprising porous poly 2,6-diaminopyridine and ruthenium nanoparticles loaded on the surface and internal pores of the porous poly 2,6-diaminopyridine.

[0008] Preferably, the BET specific surface area of the ruthenium-poly 2,6-diaminopyridine catalytic material is 130-320 m 3 / g, the pore volume is 0.1-1 cm 3 / g, and the pore size is 5-50 nm.

[0009] Preferably, the mass ratio of the ruthenium nanoparticles to the porous poly 2,6-diaminopyridine is 25-100:200.

[0010] The application provides a preparation method of the ruthenium-poly 2,6-diaminopyridine catalytic material.

[0011] 2,6-diaminopyridine, SiO2, and (NH4)2S2O8 are mixed, and a polymerization reaction is performed under alkaline conditions to obtain a poly 2,6-diaminopyridine precursor material;

[0012] The poly 2,6-diaminopyridine precursor material is pyrolyzed to obtain pyrolyzed poly 2,6-diaminopyridine;

[0013] The pyrolyzed poly 2,6-diaminopyridine is mixed with a hydrofluoric acid solution to remove the silica template, and porous poly 2,6-diaminopyridine is obtained;

[0014] The porous poly 2,6-diaminopyridine, a soluble ruthenium ion source, NaBH4, and water are mixed to perform a reduction reaction, and a ruthenium-poly 2,6-diaminopyridine catalytic material is obtained.

[0015] Preferably, the mass ratio of the 2,6-diaminopyridine to SiO2 is 1-10:30;

[0016] The mass ratio of the 2,6-diaminopyridine to (NH4)2S2O8 is 5:10-20;

[0017] The concentration of the hydrofluoric acid solution is 5-15%.

[0018] Preferably, the temperature of the polymerization reaction is 0-5℃, and the time is 8-24h;

[0019] The pyrolysis includes first-stage pyrolysis and second-stage pyrolysis, the temperature of the first-stage pyrolysis is 200-300℃, and the time is 1-1.5h; the temperature of the second-stage pyrolysis is 600-800℃, and the time is 2-3h.

[0020] The application provides application of the ruthenium-poly 2,6-diaminopyridine catalytic material in degrading antibiotics.

[0021] The application provides a method for strengthening degradation of antibiotics by a high-iodate, which comprises the following steps:

[0022] The ruthenium-poly 2,6-diaminopyridine catalytic material, periodate and hydrogen peroxide are added to water containing antibiotics, and the pH value is adjusted to acidic to carry out an oxidative degradation reaction.

[0023] Preferably, the amount of the ruthenium-poly 2,6-diaminopyridine catalyst material added to the water body is 50 to 200 mg / L;

[0024] The concentration of the periodate in the water body is 0.1 to 15 mmol / L;

[0025] The concentration of the hydrogen peroxide in the water body is 0.1 to 15 mmol / L.

[0026] Preferably, the pH value of the water body after pH adjustment is 1-5.

[0027] The present invention provides a ruthenium-poly 2,6-diaminopyridine (Ru-PDAP) catalytic material, comprising porous poly 2,6-diaminopyridine (PDAP) and ruthenium nanoparticles (Ru) loaded on the surface and internal pores of the porous poly 2,6-diaminopyridine. The ruthenium-poly 2,6-diaminopyridine catalytic material provided by the present invention has a good hole structure. PDAP acts as an electron donor to provide activation sites for periodate. The mutual conversion of various valence states of ruthenium (0, 2+, 3+, 4+, 6+, 8+) can provide more electrons for periodate to oxidize and degrade organic matter. Periodate / hydrogen peroxide can produce more active substances (such as ·OH, IO3) through the activation of the ruthenium-poly 2,6-diaminopyridine catalytic material. ·- 、 1 O2, etc.), broadening the pH range of action to efficiently remove antibiotic contaminants. Therefore, the ruthenium-poly 2,6-diaminopyridine catalytic material provided by the present invention has a good catalytic effect on the degradation of antibiotics by periodate / hydrogen peroxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 N2 isothermal adsorption-desorption curves of PDAP and Ru-PDAP (50:200);

[0029] Figure 2 SEM images of PDAP at 5.0k times (a) and 50.0k times (b);

[0030] Figure 3 SEM images of Ru-PDAP (25:200) at 20.0k times (a) and 50.0k times (b);

[0031] Figure 4 SEM images of Ru-PDAP (50:200) at 20.0k times (a) and 50.0k times (b);

[0032] Figure 5 SEM images of Ru-PDAP (100:200) at 20.0k times (a) and 50.0k times (b);

[0033] Figure 6 EDS analysis of PDAP, Ru-PDAP (25:200), Ru-PDAP (50:200), and Ru-PDAP (100:200);

[0034] Figure 7 Analysis of the full XPS spectrum of Ru-PDAP and the spectra of each element;

[0035] Figure 8 XRD spectra of PDAP and Ru-PDAP (50:200);

[0036] Figure 9 FTIR analysis charts of PDAP, Ru-PDAP (50:200) and Ru-PDAP (100:200);

[0037] Figure 10 The effect of different Ru addition contents in Ru-PDAP on the degradation of SPD by PI / H2O2;

[0038] Figure 11 for Figure 11 The effect of different Ru-PDAP addition amounts on the degradation of SPD by PI / H2O2;

[0039] Figure 12 The effect of different pH values ​​on the degradation of SPD by PI / H2O2;

[0040] Figure 13 The effect of different temperatures on the degradation of SPD by PI / H2O2;

[0041] Figure 14 The effect of different periodate and hydrogen peroxide ratios on the degradation of SPD by PI / H2O2;

[0042] Figure 15 The effect of different sulfapyridine concentrations on the degradation of SPD by PI / H2O2. DETAILED DESCRIPTION

[0043] The present invention provides a ruthenium-poly 2,6-diaminopyridine (Ru-PDAP) catalytic material, comprising porous poly 2,6-diaminopyridine (PDAP) and ruthenium nanoparticles (Ru) loaded on the surface and internal pores of the porous poly 2,6-diaminopyridine.

[0044] In the present invention, the mass ratio of the ruthenium nanoparticles to the porous poly-2,6-diaminopyridine is preferably 25-100:200, more preferably 50-100:200. In the present invention, the particle size of the ruthenium-poly-2,6-diaminopyridine catalytic material is preferably 4-15 nm. In the present invention, the ruthenium element in the ruthenium nanoparticles exists primarily as a single substance, followed by +2-valent compounds, +3-valent compounds, +4-valent compounds, +6-valent compounds, and +8-valent compounds.

[0045] In the present invention, the BET specific surface area of ​​the ruthenium-poly 2,6-diaminopyridine catalyst material is preferably 130 to 320 m 3 / g, and the pore volume is preferably 0.1 to 1 cm 3 / g, and the pore diameter is preferably 5 to 50 nm. In the present invention, the pore volume is preferably obtained by single-point adsorption test, and the pore diameter is preferably obtained by BET test.

[0046] The present invention provides a method for preparing the above-mentioned ruthenium-poly 2,6-diaminopyridine catalytic material, comprising the following steps:

[0047] 2,6-diaminopyridine, SiO2, and (NH4)2S2O8 are mixed and polymerized under alkaline conditions to obtain a poly-2,6-diaminopyridine precursor material;

[0048] Pyrolyzing the poly 2,6-diaminopyridine precursor material to obtain thermally decomposed 2,6-diaminopyridine;

[0049] mixing the thermally depolymerized 2,6-diaminopyridine with a hydrofluoric acid solution to remove the silica template to obtain porous poly-2,6-diaminopyridine;

[0050] The porous poly 2,6-diaminopyridine, a soluble ruthenium ion source, NaBH4 and water are mixed and subjected to a reduction reaction to obtain a ruthenium-poly 2,6-diaminopyridine catalytic material.

[0051] The present invention mixes 2,6-diaminopyridine, SiO2, (NH4)2S2O8 and water, and performs a polymerization reaction under alkaline conditions to obtain a poly-2,6-diaminopyridine precursor material. In the present invention, the mass ratio of the 2,6-diaminopyridine to SiO2 is preferably 1 to 10:30, more preferably 5:30;

[0052] The mass ratio of 2,6-diaminopyridine to (NH4)2S2O8 is preferably 5:10-20, more preferably 5:18;

[0053] The mass ratio of the 2,6-diaminopyridine to water is preferably 5:500.

[0054] The present invention preferably uses NaOH to provide an alkaline environment. In the present invention, the mass ratio of the 2,6-diaminopyridine to NaOH is preferably 2 to 10:1, more preferably 5:1.

[0055] In the present invention, the mixing method is preferably:

[0056] Mix 2,6-diaminopyridine and SiO2 with the first portion of water, disperse them ultrasonically, and cool the resulting mixture to 0°C to obtain a premixed solution;

[0057] Combine NaOH, (NH4)2S2O8 and a second portion of water and add the resulting mixture to the premix.

[0058] In the present invention, the power of the ultrasound is preferably 80 kHz, and the time is preferably 30 min.

[0059] In the present invention, the mass ratio of the first portion of water to the second portion of water is preferably 4:1.

[0060] In the present invention, the polymerization reaction is preferably carried out at a temperature of 0 to 5° C., and for a time of 8 to 24 hours, more preferably 10 to 18 hours. In the present invention, the polymerization reaction is preferably carried out under stirring.

[0061] In the present invention, in the polymerization reaction, the (NH4)2S2O8 acts as an initiator to generate free radicals to carry out the polymerization reaction of 2,6-diaminopyridine; the alkaline reagent NaOH acts as a polymerization agent.

[0062] After the polymerization reaction, the present invention preferably performs post-treatment on the obtained polymerization reaction solution, and the post-treatment preferably includes the following steps:

[0063] The polymerization reaction liquid is sequentially subjected to solid-liquid separation, and the obtained solid is washed and dried to obtain a poly 2,6-diaminopyridine precursor material.

[0064] In the present invention, the solid-liquid separation method is preferably suction filtration; the detergent used in the washing is preferably deionized water; the drying method is preferably oven drying, and the drying temperature is preferably 60° C. After the drying, a gray solid is obtained.

[0065] After obtaining the poly-2,6-diaminopyridine precursor material, the poly-2,6-diaminopyridine precursor material is pyrolyzed to obtain pyrolyzed poly-2,6-diaminopyridine. In the present application, the pyrolysis is preferably carried out in a tube furnace, and the atmosphere of the pyrolysis is preferably N2. In the present application, the pyrolysis preferably comprises a first-stage pyrolysis and a second-stage pyrolysis, the temperature of the first-stage pyrolysis is preferably 200-300℃, more preferably 200-250℃, the holding time is preferably 1-1.5h, more preferably 1h, and the heating rate to the first-stage pyrolysis temperature is preferably 6℃ / min; the temperature of the second-stage pyrolysis is preferably 600-800℃, more preferably 700-800℃; the holding time is preferably 2-3h, more preferably 2h, and the heating rate to the second-stage pyrolysis temperature is preferably 5℃ / min. After the pyrolysis, a black powder is obtained. Through the pyrolysis, the specific surface area and pore volume of the poly-2,6-diaminopyridine can be increased, the surface impurities can be removed, and oxygen vacancy structures can be generated, so that the catalytic ability can be improved.

[0066] After obtaining the pyrolyzed poly-2,6-diaminopyridine, the pyrolyzed poly-2,6-diaminopyridine is mixed with a hydrofluoric acid solution to remove the SiO2 template to obtain porous poly-2,6-diaminopyridine. In the present application, the mass concentration of the hydrofluoric acid solution is preferably 5-15%, more preferably 10%. In the present application, the mixing is preferably oscillation mixing, which is preferably carried out in a constant-temperature shaking incubator. In the present application, the mixing time (i.e. the time for removing the SiO2 template) is preferably 6-48h, more preferably 12h.

[0067] After the mixing is completed, the obtained mixture is preferably subjected to solid-liquid separation, the obtained solid is washed and dried to obtain porous poly-2,6-diaminopyridine. In the present application, the solid-liquid separation is preferably suction filtration; the washing agent is preferably ethanol and deionized water. In the present application, the drying is preferably oven drying, and the drying temperature is preferably 60℃, and the time is preferably 24h.

[0068] After obtaining the porous poly-2,6-diaminopyridine, the porous poly-2,6-diaminopyridine, a soluble ruthenium ion source, NaBH4 and water are mixed to carry out a reduction reaction to obtain a ruthenium-poly-2,6-diaminopyridine catalytic material. In the present application, the soluble ruthenium ion source is preferably RuCl3.

[0069] In the present application, the mass ratio of the porous poly-2,6-diaminopyridine to Ru in the soluble ruthenium ion source is preferably 25-100:200, more preferably 50-75:200. The present application does not have special requirements for the specific amount of NaBH4, and an excess amount is sufficient.

[0070] In the present invention, the mixing method preferably includes the following steps:

[0071] The porous poly-2,6-diaminopyridine and water are first ultrasonically mixed, a soluble ruthenium ion source is added, and a second ultrasonic mixing and a first stirring mixing are sequentially performed to obtain a premixed solution;

[0072] The premixed solution was cooled to 0° C., and NaBH 4 solution was added, followed by a third ultrasonic mixing and a second stirring mixing.

[0073] In the present invention, the power of the first ultrasonic mixing, the second ultrasonic mixing, and the third ultrasonic mixing is preferably 80 kHz, and the time is preferably 30 min. In the present invention, the first ultrasonic mixing and the second ultrasonic mixing are preferably carried out in a water bath, and the third ultrasonic mixing is preferably carried out in an ice bath.

[0074] In the present invention, the first stirring and mixing and the second stirring and mixing are preferably carried out at room temperature. The first stirring and mixing time is preferably 4 hours, and the second stirring and mixing time is preferably 2 hours.

[0075] In the present invention, during the third ultrasonic mixing and the second stirring mixing, the soluble ruthenium ion source undergoes a reduction reaction with NaBH4.

[0076] After the reduction reaction, the present invention preferably performs post-treatment on the obtained reduction reaction solution, and the post-treatment preferably includes the following steps:

[0077] The reduction reaction liquid is sequentially subjected to solid-liquid separation, and the resulting solid is washed and dried to obtain a ruthenium-poly-2,6-diaminopyridine catalytic material solid. In the present invention, the solid-liquid separation method is preferably suction filtration; the washing detergent is preferably ethanol and water. In the present invention, the drying method is preferably oven drying, and the drying temperature is preferably 60°C, and the drying time is preferably 24 hours.

[0078] The present invention provides the use of the above-mentioned ruthenium-poly 2,6-diaminopyridine catalytic material in the degradation of antibiotics. In the present invention, the antibiotic is preferably a sulfonamide antibiotic.

[0079] The present invention provides a method for enhancing the degradation of antibiotics by periodate, comprising the following steps:

[0080] The ruthenium-poly 2,6-diaminopyridine catalytic material, periodate and hydrogen peroxide are added to water containing antibiotics, and the pH value is adjusted to acidic to carry out an oxidative degradation reaction.

[0081] In the present invention, any type of antibiotic can be oxidatively degraded using the method of the present invention. As a specific embodiment of the present invention, the antibiotic is preferably a sulfonamide antibiotic, and more preferably one or more of sulfadiazine, sulfapyridine and sulfamethoxazole. In the present invention, the water body containing the antibiotic is preferably surface water, groundwater, sewage treatment plant influent or sewage treatment plant effluent. In the present invention, the concentration of the antibiotic in the water body containing the antibiotic is preferably 5μg / L~50mg / L, more preferably 10~40mg / L, more preferably 20~30mg / L.

[0082] In the present invention, the amount of the ruthenium-poly 2,6-diaminopyridine catalyst material added to the water body is preferably 50 to 200 mg / L, more preferably 100 to 150 mg / L.

[0083] In the present invention, the periodate is preferably sodium periodate; the concentration of the periodate in water is preferably 0.1 to 15 mmol / L, more preferably 1 to 5 mmol / L, and further preferably 2 mmol / L.

[0084] In the present invention, the concentration of hydrogen peroxide in water is preferably 0.1 to 15 mmol / L, more preferably 1 to 5 mmol / L, and even more preferably 2 mmol / L. In the present invention, the molar ratio of periodate to hydrogen peroxide is preferably (0.1 to 15):1, more preferably (1 to 10):1, and even more preferably 1:1.

[0085] In the present invention, after adjusting the pH value to acidic, the pH value of the water body is preferably 1 to 5. In the present invention, the acid used for coupling with hydrogen peroxide is preferably one or more of hydrochloric acid, sulfuric acid, and phosphoric acid, more preferably hydrochloric acid.

[0086] The present invention has no special requirements for the method of adding and mixing the ruthenium-poly 2,6-diaminopyridine catalyst material, acid, periodate, and hydrogen peroxide. The adding and mixing methods well known to those skilled in the art can be used, such as stirring and mixing.

[0087] In the present invention, the temperature of the oxidative degradation reaction is preferably 10-60° C., more preferably 20-50° C., and further preferably 30-40° C.; and the time is preferably ≤60 min, more preferably ≤30 min.

[0088] The ruthenium-poly 2,6-diaminopyridine catalytic material provided by the present invention, its preparation method and application are described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0089] Example 1

[0090] The method for preparing ruthenium-poly 2,6-diaminopyridine catalytic material (Ru-PDAP) is as follows:

[0091] (1) Polymerization: 5.0 g of 2,6-diaminopyridine and 30 g of SiO2 were dissolved in 400 mL of deionized water, and ultrasonic dispersion was performed for 30 min to obtain a mixture which was cooled to 0°C. 1.0 g of NaOH and 18.0 g of (NH4)2S2O8 were dissolved in 100 mL of deionized water at 0°C, and the foregoing mixture was added. The polymerization reaction was stirred in an ice bath for 12 h. The product was separated by suction filtration and rinsed with 200 mL of deionized water for 3 times. Drying in a 60°C oven obtained a gray solid.

[0092] (2) Pyrolysis: The gray solid was ground into powder, and pyrolysis was performed in a tube furnace (under N2) at an initial temperature of 25°C, with a temperature increase of 6°C / min to 200°C, for 1 h, and then with a temperature increase of 5°C / min to 800°C, for 2 h.

[0093] (3) Removal of SiO2 template: The black powder obtained by pyrolysis was added to 200 mL of 10% HF solution, and oscillation was performed in a constant-temperature oscillation box for 12 h. The obtained solid was subjected to suction filtration, rinsed with 100 mL of ethanol for 2 times, rinsed with 100 mL of deionized water for 2 times, and dried in a 60°C oven for 24 h to obtain black powder PDAP.

[0094] (4) Preparation of Ru-PDAP (25:200): 200±10 mg of prepared PDAP was dispersed in 10 mL of deionized water, and water bath ultrasonic dispersion was performed for 30 min, and then 64.84±0.50 mg of RuCl3·H2O solution (containing 25 mg of Ru) was added at room temperature, water bath ultrasonic dispersion was performed for 30 min, and stirring was performed at room temperature for 4 h. The mixture solution was cooled to 0°C, and then 5 mL of 0.5M NaBH4 was added dropwise, ultrasonic dispersion was performed in an ice bath for 30 min, and stirring was performed at room temperature for 2 h. Meanwhile, multiple groups were prepared, and the prepared Ru-PDAP was collected by suction filtration, rinsed with 50 mL of ethanol and water for 2 times, and dried in a 60°C oven for 24 h to obtain Ru-PDAP (25:200).

[0095] Example 2

[0096] PDAP was prepared according to the method of Example 1;

[0097] Preparation of Ru-PDAP (50:200): 200±10 mg of prepared PDAP was dispersed in 10 mL of deionized water, and water bath ultrasonic dispersion was performed for 30 min, and then 129.36±5 mg of RuCl3·H2O solution (containing 50 mg of Ru) was added at room temperature, and the remaining steps were the same as those in the preparation of Ru-PDAP (25:200), to obtain Ru-PDAP (50:200).

[0098] Example 3

[0099] PDAP was prepared according to the method of Example 1;

[0100] Preparation of Ru-PDAP (100:200): 200 ± 10 mg of the prepared PDAP was dispersed in 10 mL of deionized water and sonicated in a water bath for 30 min. Then, 258.72 ± 10 mg of RuCl3·H2O solution (containing 100 mg of Ru) was added at room temperature. The remaining steps were the same as those for the preparation of Ru-PDAP (25:200) to obtain Ru-PDAP (100:200).

[0101] Structural characterization

[0102] (1) Surface area, pore volume and pore size analysis

[0103] The surface area, pore volume and pore size test results of PDAP and Ru-PDAP (50:200) are shown in Table 1.

[0104] Table 1 Surface area, pore volume and pore size of PDAP and Ru-PDAP (50:200)

[0105]

[0106] As can be seen from Table 1, the specific surface area of ​​PDAP is 314.04 m 2 / g, the specific surface area of ​​Ru-PDAP is 139.44m 2 / g. The pore volumes are 0.8586cm 3 / g and 0.3098cm 3 / g, and the pore diameters are 10.9356nm and 8.8863nm, respectively. Comparing PDAP and Ru-PDAP, it can be found that the specific surface area, pore volume and pore diameter of PDAP are all larger than those of Ru-PDAP, which indicates that Ru is successfully loaded on the surface and micropores of PDAP.

[0107] N2 isothermal adsorption-desorption curves of PDAP (a) and Ru-PDAP (50:200) (b) are shown in Figure 2. Figure 1 shown.

[0108] According to the six adsorption-desorption isotherms classified by IUPAC, the N2 adsorption-desorption isotherms of PDAP and Ru-PDAP are closest to the "Ⅳ" type isotherm. Figure 1As can be seen in the figure, the adsorption amount increases gradually in the low-pressure range. At this point, N₂ molecules adsorb on the inner surface of the mesopores in monolayer to multilayer forms. For ordered mesoporous materials, a relative pressure of P / P₀ = 0.05 to 0.60 is suitable for calculating the specific surface area using the BET method. There is a sudden increase in adsorption at around P / P₀ = 0.8 to 0.9. The position of this range reflects the pore size of the sample, and the width of this variation can be used as a measure of mesopore uniformity. The desorption isotherm is above the adsorption isotherm. Based on the type of mesoporous hysteresis loop, it is an H1 type hysteresis loop. The presence of this hysteresis loop indicates that the material has accumulated to form mesopores. A saturated adsorption plateau is present on the adsorption isotherm, reflecting a relatively uniform pore size distribution.

[0109] (2) Morphology analysis of Ru-PDAP

[0110] Figures 2 to 5 The scanning electron microscope (SEM) images of PDAP, Ru-PDAP (25:200), Ru-PDAP (50:200) and Ru-PDAP (100:200) at different magnifications are shown. Figure 2 SEM images of PDAP at 5.0k times (a) and 50.0k times (b); Figure 3 SEM images of Ru-PDAP (25:200) at 20.0k times (a) and 50.0k times (b); Figure 4 SEM images of Ru-PDAP (50:200) at 20.0k times (a) and 50.0k times (b); Figure 5 SEM images of Ru-PDAP (100:200) at 20.0kx (a) and 50.0kx (b) magnifications are shown. The PDAP exhibits a relatively large number of cavities, while the Ru-PDAP (25:200) exhibits uniform luminescence loading. When the Ru content is increased to 50mg and 100mg, respectively, more luminescence points are observed, indicating that more Ru is successfully loaded onto the PDAP. This clearly demonstrates that both Ru-PDAPs were successfully prepared and possess a well-defined cavitation structure.

[0111] Figure 6EDS analysis of PDAP (a), Ru-PDAP (25:200) (b), Ru-PDAP (50:200) (c), and Ru-PDAP (100:200) (d). Figures (b) through (d) show that the distribution of Ru matches the luminescent areas in the SEM images, indicating that Ru is uniformly distributed throughout the PDAP. The compositional distribution shows that the mass percentage of Ru approximates the amount added to the raw materials. The EDS analysis result for Ru-PDAP (25:200) (wRu = 11.1%) is 9.5%, for Ru-PDAP (50:200) (wRu = 20%) it is 22.1%, and for Ru-PDAP (100:200) (wRu = 33.3%) it is 39.8%.

[0112] (3) XPS analysis

[0113] Figure 7 Analysis of the full XPS spectrum of Ru-PDAP and the spectra of each element. Figure 7 In the figure, (a) is the full XPS spectrum; (b) is the O1s spectrum; (c) is the N1s spectrum; (d) is the C1s spectrum; (e) is the Ru 3p spectrum; and (f) is the Ru 3d spectrum. Figure (a) shows that the Ru 3d core energy level overlaps with the C1s core energy level in the spectrum, making it difficult to identify the Ru species. Therefore, the Ru 3p orbital was also analyzed to better quantitatively and qualitatively determine the Ru state.

[0114] For O1s, the main coordination peaks fitted are at 530.48 eV, 531.76 eV, and 533.27 eV, corresponding to lattice oxygen, CO, and C=O, respectively. Lattice oxygen includes various high-valent oxides of Ru, namely, Ru-O. For N1s, the fitting results are 401.33 eV (C-NH2), 399.98 eV (pyrrolidine N), and 398.47 eV (pyridine N), which are related to the structure of 2,6-diaminopyridine. For C1s, the fitting results include 284.80 eV (C-C / C=C), 286.32 eV (CO-C / C-OH / C=N), and 288.20 eV (O=CO). Therefore, the functional groups on the PDAP surface can effectively promote electron transfer. The peaks at 280.23eV, 280.84eV and 282.10eV are the overlapping peaks of C1s and Ru 3d, mainly Ru 3d 5 / 2 , representing the presence of high-valent Ru oxides or Ru-N, such as Ru(Ⅲ) / Ru(Ⅳ). In the Ru 3p spectrum, the binding energy is divided into Ru 3p 1 / 2 Orbitals and Ru 3p 3 / 2 orbital, of which 484.22eV (Ru 3p 1 / 2 ) and 461.96eV(Ru 3p3 / 2 ) represents Ru(0), 485.75 eV (Ru 3p 1 / 2 ) and 463.60 eV (Ru 3p 3 / 2 ) represents Ru(IV). For the binding energy analysis of Ru 3d orbitals, it can be found that the 3d orbitals can also be divided into Ru 3d 3 / 2 orbitals and Ru 3d 5 / 2 orbitals, where 280.43 eV (Ru 3d 5 / 2 ) and 284.80 eV (Ru 3d 3 / 2 ) are Ru(0), 281.15 eV (Ru 3d 5 / 2 ) and 286.05 eV (Ru 3d 3 / 2 ) are Ru(II / III), 282.37 eV (Ru 3d 5 / 2 ) and 287.16 eV (Ru 3d 3 / 2 ) are Ru(IV) or higher valence. However, since there is overlap between Ru 3d orbitals and C 1s, 284.80 eV may also contain C 1s. Therefore, it can be observed that the mutual transformation of various valence states of Ru (0, 2+, 3+, 4+, 6+, 8+) can provide more electrons for the oxidation degradation of organic matter by periodate.

[0115] (4) XRD analysis

[0116] Figure 8 XRD spectra of PDAP (a) and Ru-PDAP (50:200) (b). It can be seen that PDAP mainly has carbon structure, which corresponds to the 002 crystal plane (diffraction angle of 26.38°) of graphite carbon, which is conducive to providing active sites for periodate with PDAP as an electron donor. In addition, it still has a certain amino pyridine structure. Ru-PDAP (50:200) has obvious carbon structure and hexagonal crystal structure of Ru (PDF # 06-0663). This proves the successful preparation of Ru-PDAP and its good structural characteristics.

[0117] (5) Zero charge point

[0118] If the charging condition of the solid surface is related to the pH of the solution, there must be a certain pH value at which the charges of various sources on the solid surface are zero, and this pH value is the zero charge point of the solid. At the isoelectric point, the system is usually in an unstable state. Figure 9Figure 2 shows the zeta potential of Ru-PDAP (50:200) at pH 1, 3, 5, 7, 9, and 11. Under these conditions, the zeta potential is 8.40, 4.55, -1.73, -15.03, -20.70, and -22.03 mV, respectively. The zero charge point is pH 4.63, where Ru-PDAP is unstable. When pH < 4.63, the Ru-PDAP (50:200) system is positively charged, and the charge increases with decreasing pH; when pH > 4.63, the Ru-PDAP (50:200) system is negatively charged, and the charge increases with increasing pH. In addition, the smaller the molecules or dispersed particles, the higher the absolute value of the zeta potential and the more stable the system. When the absolute value of the zeta potential is lower, the more likely it is to aggregate, and the system tends to be unstable. Therefore, Ru-PDAP (50:200) has a certain instability near pH 5. Low pH values ​​will reduce IO4 - Electrostatic repulsion between Ru-PDAP and the positively charged surface of the catalyst allows the activation of PI because it exerts a favorable electrostatic force on PI at pH < 4.63. - The species predominates at pH values ​​below 8.0, while its dimeric form (H3IO6 2- ) is dominant. With IO4 - / IO3 - (1.298V) compared to the reduction potential of H3IO6 2- / IO3 - The reduction potential of Ru-PDAP is low (0.686 V), which may be the reason for the low efficiency of PI / H2O2 in degrading SPD at higher pH values. When pH>4.63 is zero, the surface of Ru-PDAP is negatively charged, which indicates that the increase in pH may lead to electrostatic repulsion between Ru-PDAP and other forms of PI, thereby alleviating the inhibition of pollutant degradation.

[0119] (6) Ru dissolution

[0120] To clarify the activity and stability of Ru-PDAP, the dissolution of metallic Ru was tested under different material ratios and reaction conditions. The dissolution of Ru under different material ratios and reaction conditions is shown in Table 2.

[0121] Table 2 Ru dissolution under different materials and reaction conditions

[0122]

[0123]

[0124] In the PI / H₂O₂ / Ru-PDAP system at pH 7, Ru concentrations of 25:200, 50:200, and 100:200 were tested, resulting in Ru dissolution rates of 2.34, 2.04, and 0.70%, respectively. Although the Ru-PDAP (25:200) solution contained the least amount of added Ru, it exhibited the highest Ru dissolution rate, while the Ru-PDAP (100:200) solution exhibited the lowest. At pH 3, the Ru dissolution rate from the Ru-PDAP (50:200) solution increased by 0.008 mg / L compared to that from the pH 7 solution. In contrast, the dissolution of Ru-PDAP (25:200) in ultrapure water increased slightly, while that of Ru-PDAP (50:200) did not dissolve. Furthermore, the dissolution of Ru in Ru-PDAP (100:200) was significantly reduced. This indicates that Ru-PDAP (50:200) and Ru-PDAP (100:200) are stable in the PI / H2O2 system and exhibit good catalytic performance.

[0125] Application Examples

[0126] Ru-PDAP was used in the periodate / hydrogen peroxide degradation of sulfapyridine (SPD) system to verify its catalytic effect.

[0127] (1) Influence of Ru:PDAP

[0128] PDAP, Ru-PDAP (25:200), Ru-PDAP (50:200) and Ru-PDAP (100:200) were used to degrade sulfapyridine in water. The specific conditions were: pH = 7, Ru-PDAP = 50 mg / L, initial SPD concentration = 20 mg / L, PI:H2O2 = 2mM:2mM.

[0129] Effects of different Ru addition contents in Ru-PDAP on the degradation of SPD by PI / H2O2 Figure 10 As shown. Figure 10As can be seen, the degradation rate of PI / H2O2 activated by PDAP alone was 18.78%. The addition of Ru-PDAP at different Ru addition ratios (Ru-PDAP (25:200), Ru-PDAP (50:200), and Ru-PDAP (100:200)) resulted in degradation rates of 29.68%, 44.71%, and 55.96%, respectively. Compared to the SPD degradation rate of 10.12% in the PI / H2O2 system at pH 7, the addition of PDAP increased the degradation rate by 85.6%. Ru-PDAP further enhanced the SPD degradation rates by 193.2%, 341.8%, and 452.9%, respectively. Therefore, the PI / H2O2 / Ru-PDAP system exhibits excellent SPD degradation.

[0130] (2) Effect of Ru-PDAP addition

[0131] Ru-PDAP (50:200) was used to degrade sulfapyridine in water. The specific conditions were: pH = 7, SPD = 20 mg / L, PI:H2O2 = 2mM:2mM.

[0132] Figure 11 The effect of different Ru-PDAP addition amounts on the degradation of SPD by PI / H2O2. Figure 11 As can be seen, the SPD degradation rates at addition levels of 50, 100, and 200 mg / L were 44.71%, 57.95%, and 62.81%, respectively. Compared to a 50 mg / L Ru-PDAP addition, 100 mg / L increased the SPD degradation rate by 0.28 times. However, when the Ru-PDAP addition level was further increased to 200 mg / L, the SPD degradation rate only increased by 0.08 times. Therefore, a 100 mg / L Ru-PDAP (50:200) addition level was sufficient to achieve excellent SPD degradation, increasing the SPD degradation rate by 4.73 times compared to the PI / H2O2 system.

[0133] (3) Effect of initial pH

[0134] Ru-PDAP (50:200) was used to degrade sulfapyridine in water. The specific conditions were: Ru-PDAP = 50 mg / L, SPD = 20 mg / L, PI:H2O2 = 2 mM:2 mM.

[0135] Figure 12 The effect of different pH values ​​on the degradation of SPD by PI / H2O2. Figure 12It can be seen that at initial pH values ​​between 3 and 11, the reaction almost always reaches equilibrium within approximately 1 minute, further increasing the reaction rate compared to the PI / H₂O₂ system. At initial pH values ​​of 3, 5, 7, 9, and 11, the SPD degradation rates were 99.06%, 52.40%, 44.71%, 38.38%, and 36.10%, respectively, indicating a decreasing trend with increasing pH. The SPD degradation rate varied significantly from pH 3 to 5, while the degradation rates at other pH conditions were similar. The SPD degradation rates of the PI / H₂O₂ / Ru-PDAP system at pH values ​​of 3, 7, 9, and 11 all increased compared to the PI / H₂O₂ system by 0.025, 3.42, 1.01, and 0.58 times, respectively. However, the SPD degradation rate at pH 5 decreased by 0.24 times compared to the PI / H₂O₂ system. This shows that under pH 5 conditions, the addition of Ru-PDAP is actually not conducive to the degradation of SPD. This may be because the zero charge point of Ru-PDAP is near pH 5, which makes Ru-PDAP unstable at this pH and unable to efficiently activate PI / H2O2 to produce active species and thus degrade SPD.

[0136] (4) Influence of different temperatures

[0137] Ru-PDAP (50:200) was used to degrade sulfapyridine in water. The specific conditions were: pH = 3, Ru-PDAP = 50 mg / L, SPD = 20 mg / L, PI:H2O2 = 2 mM:2 mM.

[0138] Figure 13 The effect of different temperatures on the degradation of SPD by PI / H2O2. Figure 13 It can be seen that when the reaction temperature is set to 10°C, 20°C, 30°C, and 60°C, the SPD degradation rates are 98.50%, 100.00%, 99.06%, and 99.00%, respectively. Therefore, temperature has no significant effect on the degradation of SPD by the PI / H2O2 / Ru-PDAP system.

[0139] (5) Effect of the ratio and dosage of periodate and hydrogen peroxide

[0140] Ru-PDAP (50:200) was used to degrade sulfapyridine in water under the following conditions: pH = 3, SPD = 20 mg / L.

[0141] Figure 14 The effect of different periodate and hydrogen peroxide ratios on the degradation of SPD by PI / H2O2. Figure 14It can be seen that when the PI:H2O2 ratios were 2:2, 2:1, 1:1, and 1:2 (in mM), the final SPD degradation rates were 99.06%, 93.36%, 97.79%, and 98.96%, respectively. Compared with the PI / H2O2 system with the same PI and H2O2 addition amounts and ratios, the SPD degradation rates increased by 0.025, 0.358, 0.946, and 0.070 times. This indicates that the addition of Ru-PDAP can significantly reduce the amount of oxidants PI and H2O2 used. When the PI and H2O2 addition amounts were 1 mM, nearly 100% SPD degradation was achieved within 30 minutes.

[0142] (6) Effect of initial sulfapyridine concentration

[0143] Ru-PDAP (50:200) was used to degrade sulfapyridine in water. The specific conditions were: pH = 3, Ru-PDAP = 50 mg / L, PI:H2O2 = 2mM:2mM.

[0144] Figure 15 The effect of different sulfapyridine concentrations on the degradation of SPD by PI / H2O2. Figure 15 As can be seen, the final SPD degradation rates were 100%, 100%, 99.06%, and 93.36%, respectively. Compared to the PI / H2O2 system, the SPD degradation rate increased with the addition of Ru-PDAP. In particular, when the initial SPD concentration was 50 mg / L, the SPD degradation rate increased from 75.0% to 93.36%, a 24.5% increase. This demonstrates that the addition of Ru-PDAP can promote the degradation of pollutants in the PI / H2O2 system.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for enhancing the degradation of antibiotics by periodate, comprising the following steps: In water containing antibiotics, ruthenium-poly 2,6-diaminopyridine catalytic material, periodate and hydrogen peroxide are added to adjust the pH value to acidic to carry out oxidative degradation reaction; The ruthenium-poly 2,6-diaminopyridine catalytic material comprises porous poly 2,6-diaminopyridine and ruthenium nanoparticles loaded on the surface and internal pores of the porous poly 2,6-diaminopyridine.

2. The method according to claim 1, characterized in that The amount of the ruthenium-poly 2,6-diaminopyridine catalyst material added to the water body is 50-200 mg / L; The concentration of periodate in water is 0.1-15 mmol / L; The concentration of the hydrogen peroxide in the water body is 0.1-15 mmol / L.

3. The method according to claim 1 or 2, characterized in that After adjusting the pH value, the pH value of the water body is 1~5.

4. The method according to claim 1, wherein The BET specific surface area of ​​the ruthenium-poly 2,6-diaminopyridine catalytic material is 130-320 m 2 / g, pore volume is 0.1~1cm 3 / g, pore size is 5~50 nm.

5. The method according to claim 1, wherein The mass ratio of the ruthenium nanoparticles to the porous poly 2,6-diaminopyridine is 25-100:

200.

6. The method according to claim 1, characterized in that The preparation method of the ruthenium-poly 2,6-diaminopyridine catalytic material comprises the following steps: 2,6-diaminopyridine, SiO2, and (NH4)2S2O8 are mixed and polymerized under alkaline conditions to obtain a poly-2,6-diaminopyridine precursor material; Pyrolyzing the poly 2,6-diaminopyridine precursor material to obtain thermally decomposed 2,6-diaminopyridine; mixing the thermally depolymerized 2,6-diaminopyridine with a hydrofluoric acid solution to remove the silica template to obtain porous poly-2,6-diaminopyridine; The porous poly 2,6-diaminopyridine, a soluble ruthenium ion source, NaBH4 and water are mixed and subjected to a reduction reaction to obtain a ruthenium-poly 2,6-diaminopyridine catalytic material.

7. The method according to claim 6, characterized in that The mass ratio of 2,6-diaminopyridine to SiO2 is 1-10:30; The mass ratio of 2,6-diaminopyridine to (NH4)2S2O8 is 5:10-20; The concentration of the hydrofluoric acid solution is 5-15%.

8. The method according to claim 6, characterized in that The polymerization reaction temperature is 0-5°C and the reaction time is 8-24h; The pyrolysis includes a first stage pyrolysis and a second stage pyrolysis. The temperature of the first stage pyrolysis is 200-300° C. and the time is 1-1.5 hours. The temperature of the second stage pyrolysis is 600-800° C. and the time is 2-3 hours.

Images