A polyaniline-derived carbon-doped boron nitride material, preparation method and application thereof

Abstract

The present invention belongs to the field of functional material preparation, and is specifically related to a polyaniline-derived carbon-doped boron nitride material, a preparation method and its application. The present invention uses a very small amount of polyaniline as a carbon precursor, and calcines the carbon in situ with a boron nitride precursor at high temperature to form carbon-doped boron nitride in boron nitride, so that it has two active sites of B-N-C and pyridinic nitrogen, and its ultrathin porous structure further increases the number of active sites, so that the carbon-doped boron nitride material of the present invention can efficiently activate PMS to catalyze the degradation of pollutants. When the carbon-doped boron nitride material of the present invention activates PMS to degrade sulfadiazine, it can be completely degraded in 60min without additional energy input. The preparation process of the present invention is simple, and the carbon-doped boron nitride prepared at the same time has extremely high activation PMS catalytic degradation of pollutants performance, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of functional material preparation, and specifically relates to a polyaniline-derived carbon-doped boron nitride material and a preparation method thereof, and also relates to the application of the material in activating peroxymonosulfate to degrade antibiotics. Background Art

[0002] Antibiotics are widely used in the fields of animal husbandry and human disease treatment. However, antibiotics are generally difficult to degrade after being discharged into the natural world, such as water bodies. They also have high potential risks and can cause serious impacts on nature and human health even at low concentrations. Therefore, the removal of these organic pollutants in water bodies has led to an increasing demand for efficient treatment technologies. For example, Chinese patent CN201410334628.5 discloses a few-layer boron nitride and its preparation method and application. The adsorption properties of few-layer boron nitride are used to adsorb and remove antibiotic pollutants in water bodies. However, after use, the material still needs to undergo subsequent treatment of the adsorbed antibiotic pollutants. The subsequent treatment steps are necessary and cumbersome, and the pollutants are not truly removed. In addition, in order to ensure the special pore structure of few-layer boron nitride to ensure its excellent adsorption properties, it is necessary to strictly control the temperature rise program during the preparation process, and the preparation process is complicated.

[0003] In recent years, the advanced oxidation process (AOP) based on peroxymonosulfate (PMS) activation can completely degrade and remove pollutants and has been proven to be one of the most effective methods for removing antibiotic pollutants.

[0004] Advanced oxidation technologies based on PMS activation offer rapid reaction speeds, high levels of pollutant mineralization, simple operation, and a wide range of environmental applications, showing promising development and application prospects in treating refractory organic wastewater. Heterogeneous Fenton materials can effectively activate PMS, thereby promoting the degradation of antibiotics. Furthermore, heterogeneous Fenton materials are widely studied for their ease of recycling and reuse.

[0005] Boron nitride substrate is a novel heterogeneous Fenton material with the advantages of extremely stable structure, low preparation cost and easy modification. However, its performance in activating PMS to degrade antibiotics needs to be further improved. 3+ 、Cu 2+ 、Co 2+Etc. are widely used in the doping modification of boron nitride substrate materials. For example, Chinese patent CN202210005053.7 discloses a preparation of a boron nitride material anchored cobalt ferrite composite catalyst and its application in catalytic degradation of oxytetracycline. The invention first obtains boron nitride nanotubes by high-temperature calcination, and then coprecipitates boron nitride with cobalt salts and iron salts by stirring. Finally, cobalt ferrite-doped boron nitride materials are prepared by hydrothermal method for activating PMS to degrade oxytetracycline. However, the composite catalyst material has the disadvantages of complicated preparation process and easy leaching of metal ions to cause secondary pollution. Therefore, if the introduction of metal ions in the system can be avoided, and the material is designed based on the ubiquitous and environmentally friendly non-metallic atoms in nature, the boron nitride material will have a higher application value in the field of activating PMS to degrade antibiotics. Summary of the Invention

[0006] In response to the problems existing in the doping, modification, and application of the heterogeneous Fenton material boron nitride in the prior art, the present invention aims to provide a polyaniline-derived carbon-doped boron nitride material and a preparation method thereof, as well as the application of the material in activating peroxymonosulfate to degrade antibiotics. In the present invention, a boron nitride precursor and polyaniline are calcined in a one-step process to in-situ introduce carbon into the boron nitride. The prepared polyaniline-derived carbon-doped boron nitride material is porous, ultrathin nanosheet-like and has two active sites, BNC and pyridinic nitrogen. It can efficiently activate PMS to catalyze the degradation of the antibiotic sulfadiazine, thereby improving the catalytic degradation efficiency of the antibiotic.

[0007] Based on the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a polyaniline-derived carbon-doped boron nitride material, which contains BNC active sites and pyridinic nitrogen active sites, and the doping amount of the polyaniline-derived carbon in the polyaniline-derived carbon-doped boron nitride is 0.21% to 0.32%.

[0009] The present invention dopes polyaniline-derived carbon into boron nitride to modify its structure, so that the carbon-doped boron nitride has an ultrathin nanosheet morphology and a rich porous structure. More importantly, the introduction of carbon atoms in the boron nitride, on the one hand, connects with the BN bond to generate a new active site BNC, which can complex with the polyaniline (PMS) to produce a metastable intermediate, efficiently transfer electrons and generate free radicals. On the other hand, the introduction of C changes the electron density distribution on the surface of the boron nitride, excites the surrounding pyridinic N to transform into another active site, which is conducive to triggering the PMS to produce more active substances and promotes the oxidative degradation reaction.

[0010] Experiments have found that when the doping amount of polyaniline-derived carbon in polyaniline-derived carbon-doped boron nitride is in the range of 0.21% to 0.32%, especially close to the theoretical value of 0.26%, the polyaniline-derived carbon-doped boron nitride material has better activation performance for PMS, which in turn manifests as an extremely high catalytic degradation rate for antibiotics.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0012] S1: Boric acid and urea are mixed in water, and evaporated to dryness in a water bath until the reactant is a white solid powder to prepare a boron nitride precursor;

[0013] S2: After mixing the boron nitride precursor and polyaniline in a mass ratio of 1.5: (0.002-0.5), calcining under an inert atmosphere to obtain a polyaniline-derived carbon-doped boron nitride material.

[0014] The present invention uses boric acid and urea as boron nitride precursors and a very small amount of polyaniline as a carbon precursor, and calcines them at high temperature to form carbon-doped boron nitride. This preparation method realizes in-situ doping of carbon into boron nitride to form BNC bonds, which has strong chemical bonding force. In addition, the escape of gases such as NH3 generated during the calcination process is conducive to the formation of a porous structure in the carbon-doped boron nitride material, further increasing the number of active sites. The present invention can achieve a disordered porous morphology that supports a wide range of sites through a one-step calcination, while ensuring the in-situ introduction of carbon atoms, greatly reducing the complexity of the process and simplifying the preparation process.

[0015] The polyaniline-derived carbon-doped boron nitride material prepared by the method of the present invention has two active sites: BNC and pyridinic nitrogen. These two sites activate PMS to degrade pollutants by forming electron complexes to promote electron transfer and promoting the production of highly active species from PMS, respectively. Experimental results show that the carbon-doped boron nitride of the present invention significantly improves the PMS activation performance of the boron nitride material compared to undoped boron nitride. Furthermore, the experiments also found that the pyridinic nitrogen plays a dominant role in the two active sites. With the increase of polyaniline-derived carbon, the proportion of pyridinic nitrogen gradually decreases, the proportion of BNC gradually increases, and the PMS activation performance decreases. Therefore, when the mass ratio of the boron nitride precursor to polyaniline is within the above range, so that the polyaniline-derived carbon doping amount in the polyaniline-derived carbon-doped boron nitride is 0.21% to 0.32%, the resulting polyaniline-derived carbon-doped boron nitride exhibits excellent PMS activation performance. In particular, when the mass ratio of the two is 1.5:0.005, the carbon-doped boron nitride exhibits even better PMS activation performance.

[0016] Compared with materials with a single active pathway in the prior art, the multiple reaction pathways in the polyaniline-derived carbon-doped boron nitride of the present invention greatly promote reaction efficiency. Experiments on antibiotic catalytic degradation found that when the carbon-doped boron nitride material of the present invention activated PMS to degrade 50 mg / L of sulfadiazine, it could completely degrade sulfadiazine in 60 minutes without additional energy input.

[0017] Preferably, the mass ratio of boric acid to urea is 1:(3-4.5), and the water bath heating temperature is 60°C-80°C.

[0018] The above-mentioned mass ratio of boric acid to urea can ensure that the generation of impurities during the preparation of boron nitride is minimized. The above-mentioned water bath temperature can ensure that the boron nitride mixture precursor is naturally evaporated to dryness and mixed evenly and completely.

[0019] Preferably, the calcination temperature is 850° C. to 950° C., and the calcination holding time is 4 to 6 hours.

[0020] Within the above calcination temperature and time range, especially when the calcination temperature is 900° C. and the holding time is 5 h, the formed boron nitride crystal structure is the most stable, and the doped carbon atoms are most suitable for doping into the boron nitride skeleton.

[0021] Preferably, the inert atmosphere is a nitrogen or argon atmosphere, preferably an argon atmosphere.

[0022] The inert atmosphere is preferably argon because although nitrogen and argon are both stable inert gases, nitrogen has a certain probability of incorporating additional nitrogen atoms into the boron nitride skeleton at high temperatures, which will damage the structure.

[0023] Preferably, the mixing in step S2 is grinding and mixing the boron nitride precursor and the polyaniline.

[0024] The principle of grinding and mixing is similar to that of ball milling. It uses a certain external force and the effect of van der Waals force between microscopic molecules to ensure that the carbon atom precursor is fully and evenly mixed with boric acid and urea, thereby ensuring uniform carbon atom loading during calcination and forming a stable and complete boron nitride structure.

[0025] In a third aspect, the present invention provides the use of the polyaniline-derived carbon-doped boron nitride material as a heterogeneous Fenton material in the activation of peroxymonosulfate.

[0026] The advanced oxidation process activated by peroxymonosulfate can completely degrade and remove pollutants. The polyaniline-derived carbon-doped boron nitride prepared by the present invention can efficiently activate peroxymonosulfate, which is beneficial to its ability to degrade pollutants.

[0027] In a fourth aspect, the present invention provides the use of the above-mentioned polyaniline-derived carbon-doped boron nitride material in the catalytic degradation of antibiotics.

[0028] Preferably, the polyaniline-derived carbon-doped boron nitride catalyzes the degradation of antibiotics by activating peroxymonosulfate, and the molar ratio of the polyaniline-derived carbon-doped boron nitride to the peroxymonosulfate during the catalytic antibiotic degradation treatment is (0.58-0.67):0.975.

[0029] Experiments have found that when polyaniline-derived carbon doped with boron nitride and peroxymonosulfate are used in the above-mentioned molar ratio for catalytic degradation of antibiotics, the antibiotics can be completely degraded in a short time.

[0030] Preferably, the antibiotic comprises a sulfonamide antibiotic including sulfadiazine.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention uses a very small amount of polyaniline as a carbon precursor, which is then calcined at high temperature with a boron nitride precursor to in-situ dope carbon into the boron nitride to form carbon-doped boron nitride. This material has two active sites, BNC and pyridinic nitrogen. Its ultrathin porous structure further increases the number of active sites, enabling the carbon-doped boron nitride material of the present invention to efficiently activate PMS to catalyze the degradation of pollutants. Multiple reaction pathways greatly promote reaction efficiency. When the carbon-doped boron nitride material of the present invention activates PMS to degrade sulfadiazine, it can completely degrade it in 60 minutes without additional energy input. The preparation process of the present invention is simple, and the prepared carbon-doped boron nitride has extremely high performance in activating PMS to catalyze the degradation of pollutants, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 TEM images, SEM images and physical photos of the polyaniline-derived carbon-doped boron nitride material prepared in Example 1;

[0034] Figure 2 The XRD patterns of the samples prepared in Example 1 and Comparative Examples 1 to 3 are shown below:

[0035] Figure 3 FTIR spectra of the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3;

[0036] Figure 4 The XPS spectra of the samples prepared in Example 1, Example 3, Comparative Example 1, and Comparative Example 2 are shown;

[0037] Figure 5 The degradation kinetics of sulfadiazine by the samples prepared in Examples 1 to 6 are shown;

[0038] Figure 6 The degradation kinetics of sulfadiazine by the samples prepared in Example 1 and Comparative Examples 1 to 3 are shown. Implementation Method

[0039] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below with reference to specific examples. Those skilled in the art will appreciate that the specific examples described herein are intended only to illustrate the present invention and are not intended to limit the present invention. The experimental methods used in the examples are conventional methods unless otherwise specified; the materials and reagents used are commercially available unless otherwise specified. Example

[0040] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0041] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60°C water bath until evaporated to dryness or the reactants in the beaker turn into a white solid powder to prepare a boron nitride precursor.

[0042] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.005 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a mixture of the boron nitride precursor and polyaniline.

[0043] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a polyaniline-derived carbon-doped boron nitride material, which was designated as RePBN-0.005.

[0044] The TEM images, SEM images and photos of the polyaniline-derived carbon-doped boron nitride material (RePBN-0.005) prepared in this example are as follows: Figure 1 As shown, Figure 1 a. Figure 1 b are morphology images at 0.2μm and 100nm respectively. It can be seen from the figure that RePBN-0.005 is a typical ultra-thin nanosheet morphology with a rich porous structure. Figure 1 c is a photo of the polyaniline-derived carbon-doped boron nitride material. It can be seen that the material is in a flower-shaped cluster after calcination. Figure 1 The SEM image of d also confirms this morphology, confirming the successful preparation of porous carbon-doped boron nitride material. Example

[0045] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0046] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60°C water bath until the reactants in the beaker turn into a white solid powder to obtain a boron nitride precursor.

[0047] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.002 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a mixture of the boron nitride precursor and polyaniline.

[0048] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a carbon-doped boron nitride material, which was designated as RePBN-0.002. Example

[0049] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0050] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60 °C water bath until evaporated to dryness. The reactants in the beaker turn into white solid powder, thereby obtaining a boron nitride precursor.

[0051] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.1 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a mixture of boron nitride and polyaniline.

[0052] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a polyaniline-derived carbon-doped boron nitride material, which was designated as RePBN-0.1. Example

[0053] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0054] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60°C water bath until the reactants in the beaker turn into a white solid powder to obtain a boron nitride precursor.

[0055] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.2 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a polyaniline-derived carbon-doped boron nitride material precursor.

[0056] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a polyaniline-derived carbon-doped boron nitride material, which was designated as RePBN-0.2. Example

[0057] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0058] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60°C water bath until the reactants in the beaker turn into a white solid powder to obtain a boron nitride precursor.

[0059] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.3 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a mixture of the boron nitride precursor and polyaniline.

[0060] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a polyaniline-derived carbon-doped boron nitride material, which was designated as RePBN-0.3. Example

[0061] This embodiment provides a method for preparing a polyaniline-derived carbon-doped boron nitride material, comprising the following steps:

[0062] S1: Place 2 g of boric acid and 8 g of urea in a beaker, add 50 mL of deionized water, and heat in a 60°C water bath until the reactants in the beaker turn into a white solid powder to obtain a boron nitride precursor.

[0063] S2: Weigh 1.5 g of the boron nitride precursor prepared above and 0.5 g of polyaniline into an agate mortar and grind them evenly for 15 min to obtain a mixture of the boron nitride precursor and polyaniline.

[0064] S3: The ground mixture was placed in a porcelain ark and calcined at 900° C. for 5 h in an argon atmosphere in a tube furnace to obtain a polyaniline-derived carbon-doped boron nitride material, which was designated as RePBN-0.5.

[0065] This comparative example provides a method for preparing a boron nitride material, comprising the following steps:

[0066] 2 g of boric acid and 8 g of urea were evenly ground and placed in a porcelain ark. They were calcined at 900 °C for 5 h in a tube furnace under an argon atmosphere and then cooled to room temperature under an argon atmosphere to obtain a boron nitride material, which was recorded as h-BN.

[0067] The difference between this comparative example and Examples 1-3 is that this comparative example does not undergo polyaniline-derived carbon doping treatment.

[0068] This comparative example provides a method for preparing a polyaniline-derived carbon material, comprising the following steps:

[0069] 3 g of polyaniline was ground into powder and placed in a porcelain ark. It was calcined at 900 °C for 5 h in a tube furnace under argon atmosphere and cooled to room temperature under argon atmosphere to obtain a polyaniline-derived carbon material, which was recorded as Re-PANI.

[0070] This comparative example 3 provides a method for preparing a polyaniline material, comprising the following steps:

[0071] 3 g of commercial polyaniline was ground for 20 min to a very fine black powder to obtain polyaniline material, which was recorded as PANI.

[0072] (1) XRD pattern analysis

[0073] The XRD patterns of the samples prepared in Example 1 and Comparative Examples 1 to 3 are as follows: Figure 2 As shown in the figure, it can be clearly observed that the peaks at 26.6° and 42.1° correspond to the (002) and (100) planes of boron nitride. The peak at 24° corresponds to the graphitic carbon in the polyaniline-derived carbon, and the weak impurity peak between 35° and 40° is also consistent with the peak of polyaniline-derived carbon, proving that partial bonding of the two precursors also occurs in the RePBN structure, and also proving the successful composite of polyaniline-derived carbon and boron nitride in RePBN.

[0074] (2) FTIR spectrum analysis

[0075] The FTIR spectra of the samples prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are as follows: Figure 3 As shown, from Figure 3 It can be seen that 1387.7 cm -1 The peak at 809.2 cm is the characteristic peak of BN. -1 The peak at is the characteristic peak of BNB. Both PePBN and h-BN show the above two types of bonding. It is worth noting that with the increase of the loading of polyaniline precursor, the characteristic peak of BNB gradually blue-shifts, indicating that the vibration frequency of the chemical bond becomes higher, which also implies the change of the composition and content of the surrounding chemical bonds. The quinone ring stretching bond (1576 cm) in the original PANI −1 ), benzene ring stretching bond (1481 cm −1 ), C-N single bond stretching of secondary aromatic amines (1300 cm −1 ) disappeared after calcination and were replaced by the peak of ordered graphitic carbon (1576 cm −1 ). The above confirms the synthesis of boron nitride and the introduction of C element into the boron nitride substrate.

[0076] (3) XPS spectrum analysis

[0077] The XPS spectra of Examples 1, 3, Comparative Examples 1 and 2 are as follows: Figure 4 As shown, from Figure 4The comparative spectra clearly show that, in addition to the characteristic BN peaks of pristine boron nitride, RePBN also produces a distinct pyridinic N peak derived from polyaniline-derived carbon. Furthermore, the introduction of carbon induces the formation of BNC bonds, confirming the successful atomic-level carbon doping. Comparing ReBPN materials with varying carbon loadings, it is found that as the loading increases, the proportion of pyridinic N decreases and the proportion of BNC increases. This is due to the continuous introduction of carbon atoms, consistent with the aforementioned conclusions.

[0078] The method for investigating the degradation performance of simulated pollutants provided by the present invention is as follows:

[0079] Add 15 mg of the sample prepared in Examples 1-6 to a beaker. Also, add 50 mL of a 50 mg / L sulfadiazine (SDZ) solution to the beaker. Stir the suspension with a magnetic stirrer. After adsorption equilibrium is reached, add 0.975 mM PMS to the beaker. To obtain degradation kinetic data, remove 1 mL of the solution at specified times and measure the SDZ concentration using HPLC.

[0080] The degradation kinetics of SDZ by carbon-doped boron nitride in Examples 1 to 6 are shown in FIG. Figure 5 As shown in Figure a, within 60 minutes, as the loading amount of polyaniline-derived carbon gradually decreased, the degradation activity of RePBN towards SDZ gradually increased until a peak value appeared when the addition amount was 5 mg. This is because by adjusting the loading amount, the content of active sites is also adjusted accordingly. The combined effect of BNC and pyridinic nitrogen in RePBN-0.005 on activating PMS is the strongest, which fully reflects the synergistic effect of the dual pathways.

[0081] Referring to the above method, the carbon-doped boron nitride material prepared in Example 1 was added to the beaker, and its concentration in the reaction system was adjusted to 0.1 g / L, 0.2 g / L, 0.3 g / L, and 0.4 g / L, respectively. The other parameters not mentioned were the same as the above experimental process. The degradation kinetics of SDZ by carbon-doped boron nitride materials at different concentrations are shown in FIG. Figure 5 As shown in Figure b, with the increase of catalyst input, the degradation activity gradually increased, but when the dosage increased from 0.3 g / L to 0.4 g / L, the growth rate of the degradation activity slowed down. Therefore, from the perspective of economic benefits and environmental impact, 0.3 g / L was selected as the optimal catalyst dosage concentration for the RePBN / PMS system.

[0082] Referring to the above method, the amount of PMS added to the beaker was adjusted to 0.325 mM, 0.65 mM, 0.975 mM, and 1.3 mM, respectively. The degradation kinetics of SDZ by different amounts of PMS were shown in the figure below. Figure 5As shown in Figure c, with the increase of PMS concentration, the degradation activity also showed an increasing trend. However, when the concentration was added to 1.3 mM, its degradation activity was the same as that of 0.975 mM, indicating that the degradation kinetics had reached a peak. Therefore, 0.975 mM PMS was selected as the optimal PMS addition content.

[0083] Depend on Figure 5 The results shown in this study demonstrate that, considering a comprehensive balance between economics and efficiency, carbon-doped boron nitride (RePBN-0.005) prepared by doping a 5 mg polyaniline carbon precursor at a controlled concentration of 0.3 g / L in the reaction system, combined with the addition of 0.975 mM PMS to a 50 mg / L SDZ system, exhibits the best catalytic degradation of SDZ compared to other systems. Within reasonable ranges for PMS and catalyst dosage, and under optimal conditions, the system can degrade 93.7% of SDZ within 60 minutes and 97% within 2 hours, surpassing other previously published boron nitride substrates in both reaction rate and degradation efficiency.

[0084] 15 mg of the sample prepared in Example 1 and Comparative Examples 1 and 2 was added to a beaker. 50 mL of a 50 mg / L sulfadiazine (SDZ) solution was also added to the beaker. The suspension was stirred with a magnetic stirrer. After adsorption equilibrium was reached, 0.975 mM PMS or no PMS was added to the beaker. To obtain degradation kinetic data, 1 mL of the solution was removed at specified times and the SDZ concentration was determined using HPLC.

[0085] The degradation kinetics of SDZ in Example 1, Comparative Examples 1 and 2 are as follows: Figure 6 As shown in the figure, "+PMS" means that PMS was added during the experiment, "PMS only" means that only PMS was added, and the samples prepared in Example 1 and Comparative Examples 1 and 2 were not added, and "RePBN-0.005 only" means that the sample prepared in Example 1 was added but PMS was not added to the system.

[0086] pass Figure 6The comparison confirmed the excellent degradation activity of RePBN-0.005. After the introduction of carbon into boron nitride, the degradation rate of the antibiotic sulfadiazine by the activated PMS was greatly improved compared to that without the introduction of carbon, indicating that the carbonized polyaniline greatly improved the performance of the activated PMS of the boron nitride material. This is because, on the one hand, the co-calcination of polyaniline introduced carbon atoms into the material. The introduction of carbon source can effectively change the electronic structure of the material to efficiently activate PMS. Specifically, the carbon atoms are connected to the BN bond to produce a new active site BNC, which can complex with PMS to produce a metastable intermediate, efficiently transfer electrons and generate free radicals at the same time; on the other hand, the introduction of C changes the electron density distribution on the surface, exciting the surrounding pyridine N to transform into another active site, which is conducive to attracting PMS in the system to produce more active species.

[0087] in addition, Figure 4 、 5 , 6, and 10, respectively, demonstrate that pyridinic nitrogen plays a dominant role in the system's two active sites. Increased polyaniline-derived carbon leads to decreased activity, while XPS results demonstrate that the proportion of pyridinic nitrogen decreases and that of BNC increases with increasing polyaniline loading. Therefore, it is reasonable to speculate that pyridinic nitrogen plays a greater role in the system. Consequently, carbon-doped boron nitride (i.e., a weight ratio of 0.005:1.5 polyaniline to boron nitride precursor) prepared by doping 1.5 g of a boron nitride precursor with 5 mg of polyaniline as a carbon precursor exhibits superior activation performance for PMS.

[0088] In summary, the present invention uses boric acid and urea as boron nitride precursors and a very small amount of polyaniline as a carbon precursor. The two are calcined at high temperature to form carbon-doped boron nitride. This in-situ carbon atom doping can be more tightly combined and produce stronger chemical bonding force. In addition, the escape of gases such as NH3 produced during the calcination process is conducive to the formation of a porous structure, further increasing the number of active sites. Compared with the step-by-step doping method in the prior art, the product synthesized by the present invention has an essential difference in structure, resulting in significantly higher activity.

[0089] For example, the prior art Chinese patent application CN104056590A also uses a few-layer boron nitride material for treating sulfadiazine. The material adopts an adsorption method, and the adsorbed sulfadiazine still needs to be treated after use. The subsequent steps are necessary and cumbersome, and the pollutant is not truly removed. However, the polyaniline-derived carbon-doped boron nitride of the present invention can achieve complete degradation of pollutants after recovery without any secondary treatment. Moreover, the polyaniline-derived carbon-doped boron nitride of the present invention can be directly put into another set of simulated wastewater with the same conditions without any processing after recovery, and can still achieve a degradation rate of 78.5% within 60 minutes. Extending the reaction time or acid-washing the material is expected to achieve better results. In addition, from the perspective of the preparation process, in order to ensure the special pore structure of few-layer boron nitride, the preparation method described in the prior art performs extremely detailed segmented temperature control and heating treatment on the calcination temperature. However, the carbon-doped boron nitride material of the present invention does not require detailed temperature control and can achieve a disordered porous morphology with a wide range of sites in a one-step calcination. At the same time, it can ensure the in-situ introduction of carbon atoms, greatly reducing the complexity of the process, making the preparation process simpler and easier to promote and apply.

[0090] Another example is patent publication number CN 109317183 A (A boron nitride quantum dot / ultra-thin porous carbon nitride composite photocatalytic material, its preparation method and application). From the perspective of degradation difficulty, some scholars have demonstrated through plasma energy delivery that sulfadiazine has a greater energy requirement than the tetracycline-type oxytetracycline, and is also more stable in structure and difficult to decompose. The concentration of sulfadiazine degraded by the present invention is 50 mg / L, which is much higher than the 10 mg / L oxytetracycline hydrochloride degraded by the prior art, further proving that the polyaniline-derived carbon-doped boron nitride combined with PMS of the present invention has more excellent catalytic degradation performance for antibiotics.

[0091] In addition, compared with other materials with a single activation pathway, the polyaniline-derived carbon-doped boron nitride of the present invention has two active sites, which activate PMS to degrade pollutants by forming an electron complex to promote electron transfer and promoting PMS to produce highly active substances. Multiple reaction pathways greatly promote the reaction efficiency. According to the test results, when the sample carbon-doped boron nitride material (RePBN-0.005) of the present invention activated PMS to degrade 50 mg / L sulfadiazine, it was basically degraded completely in 60 minutes without additional energy input.

[0092] In addition, no transition metal is introduced into the polyaniline-derived carbon-doped boron nitride material of the present invention, and secondary pollution problems caused by ion leaching will not occur. Moreover, the raw materials involved in the present invention are economical and easily available, and the experimental steps are simple and convenient, which has broad application prospects.

Claims

1. A polyaniline-derived carbon-doped boron nitride material, characterized in that: The polyaniline-derived carbon-doped boron nitride material contains BNC active sites and pyridinic nitrogen active sites, and the doping amount of the polyaniline-derived carbon in the polyaniline-derived carbon-doped boron nitride is 0.21% to 0.32%; The polyaniline-derived carbon-doped boron nitride material is prepared by the following method steps: S1: Boric acid and urea are mixed in water, and evaporated to dryness in a water bath until the reactant is a white solid powder to prepare a boron nitride precursor; S2: mixing a boron nitride precursor and polyaniline in a mass ratio of 1.5:0.002-0.5, and calcining the mixture under an inert atmosphere to obtain a polyaniline-derived carbon-doped boron nitride material.

2. A method for preparing the polyaniline-derived carbon-doped boron nitride material according to claim 1, characterized in that: The steps include: S1: Boric acid and urea are mixed in water, and evaporated to dryness in a water bath until the reactant is a white solid powder to prepare a boron nitride precursor; S2: mixing a boron nitride precursor and polyaniline in a mass ratio of 1.5:0.002-0.5, and calcining the mixture under an inert atmosphere to obtain a polyaniline-derived carbon-doped boron nitride material.

3. The method for preparing polyaniline-derived carbon-doped boron nitride material according to claim 2, characterized in that: The mass ratio of the boric acid to urea is 1:3-4.5, and the temperature of the water bath heating is 60° C.-80° C.

4. The method for preparing a polyaniline-derived carbon-doped boron nitride material according to claim 2, wherein: The calcination temperature is 850°C to 950°C, and the calcination holding time is 4 to 6 hours.

5. The method for preparing polyaniline-derived carbon-doped boron nitride material according to claim 2, characterized in that: The inert atmosphere is nitrogen or argon atmosphere.

6. The method for preparing a polyaniline-derived carbon-doped boron nitride material according to claim 2, characterized in that: The mixing in step S2 is to grind and mix the boron nitride precursor and polyaniline.

7. Use of the polyaniline-derived carbon-doped boron nitride material according to claim 1 as a heterogeneous Fenton material in peroxymonosulfate activation.

8. Use of the polyaniline-derived carbon-doped boron nitride material according to claim 1 in catalytic degradation of antibiotics, characterized in that: The polyaniline-derived carbon-doped boron nitride catalyzes the degradation of antibiotics by activating peroxymonosulfate.

9. The use according to claim 8, characterized in that During the catalytic antibiotic degradation treatment, the molar ratio of polyaniline-derived carbon-doped boron nitride to peroxymonosulfate is 0.58-0.67:0.

975.

10. The use according to claim 8, characterized in that The antibiotics include sulfonamide antibiotics, and the sulfonamide antibiotics include sulfadiazine.

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