Catalyst for activating persulfate as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for activating persulfate as well as a preparation method and application of the catalyst, and belongs to the technical field of catalytic materials and the technical field of water treatment. The preparation method comprises the step of calcining a mixture of graphite-like carbon nitride and coal to obtain the catalyst for activating persulfate. According to the catalyst for activating the persulfate, graphite-like carbon nitride serves as a nitrogen source, coal serves as a carbon source, the catalyst for activating the persulfate is prepared through a simple calcination method, the problem of catalytic inertia of the coal is solved, the yield is high, further purification is not needed, the catalyst can be directly used, the preparation process is simple and convenient, reaction conditions are universal, and the catalyst has high application value; the industrial production is convenient.

Description

Technical Field

[0001] The present disclosure relates to the technical field of catalytic materials and the technical field of water treatment, and in particular to a catalyst for activating persulfate, a preparation method thereof, and an application thereof. Background Art

[0002] The abuse and improper handling of antibiotics have led to pollution of surface water, groundwater and soil. The human body or animals can absorb some antibiotics, and the rest are excreted from the body and enter the sewage treatment plant, often accompanied by the production of drug-resistant bacteria, which are difficult to be biodegraded and then enter the environment. The accumulation of antibiotics in the environment may also cause drug resistance in the human body.

[0003] Advanced oxidation technology (AOP) based on persulfate can produce free radicals and non-free radicals. It is an efficient and inexpensive method for degrading antibiotics in water, and has broad application prospects in the field of sewage treatment. The key to activating persulfate technology to produce free radicals and non-free radicals is the catalyst. Among them, precious metal catalysts have high activation efficiency, but their cost is high; metal-based catalysts have metal dissolution, and metal-based catalysts are prone to agglomeration during the persulfate activation process, making the active sites insufficient; the performance of carbon catalysts in activating persulfate is lower than that of metal catalysts. Summary of the invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides a catalyst for activating persulfate, and a preparation method and application thereof.

[0005] According to an embodiment of one aspect of the present disclosure, a method for preparing an activated persulfate catalyst is provided, comprising: calcining a mixture of graphite-like carbon nitride and coal to obtain an activated persulfate catalyst.

[0006] According to an embodiment of the present disclosure, the calcination temperature is 500-800° C. and the calcination time is 2-4 hours.

[0007] According to an embodiment of the present disclosure, the calcination is performed under a protective atmosphere.

[0008] According to an embodiment of the present disclosure, the mass ratio of the above-mentioned graphite-like carbon nitride and coal is (0.5~3):1.

[0009] According to an embodiment of the present disclosure, the above-mentioned coal is natural coal or natural coal that has been pretreated.

[0010] According to an embodiment of the present disclosure, the above-mentioned natural coal is one or more of coking coal, anthracite, sub-bituminous coal, bituminous coal or lignite.

[0011] According to an embodiment of another aspect of the present disclosure, a catalyst for activating persulfate prepared by the above preparation method is provided.

[0012] According to an embodiment of another aspect of the present disclosure, there is provided the use of the above-mentioned catalyst for activating persulfate in degrading antibiotics in water.

[0013] According to an embodiment of the present disclosure, the above catalyst for activating persulfate and persulfate are added to water containing antibiotics to achieve degradation of the antibiotics in the water.

[0014] According to an embodiment of the present disclosure, the mass ratio of the catalyst for activating persulfate to the persulfate is 1:(0.6~2.4).

[0015] According to an embodiment of the present disclosure, the mass ratio of the antibiotic in the water to the persulfate is 1:(12~48).

[0016] According to an embodiment of the present disclosure, the initial pH of the antibiotic-containing water is 3-11.

[0017] According to an embodiment of the present disclosure, the above-mentioned antibiotics are one or more of tetracycline, chlortetracycline, oxytetracycline, ciprofloxacin, sulfamethoxazole, sulfachloropyridazine, sulfadiazine, sulfa, sulfamethazine and bisphenol A.

[0018] According to the embodiments of the present disclosure, the above-mentioned activated persulfate catalyst can be reused after washing and drying.

[0019] According to the embodiments of the present disclosure, a catalyst for activated persulfate is prepared by a simple calcination method using graphite-like carbon nitride as a nitrogen source and coal as a carbon source, thereby solving the problem of the catalytic inertness of coal, having a high yield, and can be used directly without further purification. The preparation process is simple, the reaction conditions are universal, the catalyst has a high application value, and is convenient for industrial production.

[0020] The catalyst for activating persulfate provided in the embodiments of the present disclosure has a high specific surface area, rich pores, and a high degree of defects. At the same time, it fully utilizes the amorphous carbon in natural coal and the metals in the coal, etc., without the need to add additional metal salts, that is, it can form active sites such as graphite N, pyridine N, pyrrole N, metal-N, C=O, etc. to activate persulfate to produce a variety of active species, thereby degrading antibiotics.

[0021] The catalyst for activating persulfate provided in the embodiments of the present disclosure improves the inertness of coal-activated persulfate, can accelerate the production of active substances by persulfate to efficiently degrade antibiotics in water, and has the advantages of high degradation rate, fast reaction rate, strong environmental adaptability, good stability, and environmental friendliness. In addition, the catalyst for activating persulfate provided in the embodiments of the present disclosure can be reused after washing and drying, and the degradation rate can still be maintained at a high level. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The scanning electron microscope test image of the activated persulfate catalyst prepared in Example 1 is shown;

[0023] Figure 2 The Fourier transform infrared spectra test diagrams of the activated persulfate catalyst and natural coal prepared in Example 1 are shown;

[0024] Figure 3 The X-ray photoelectron spectroscopy test diagram of the activated persulfate catalyst and natural coal prepared in Example 1 is shown;

[0025] Figure 4 The N 1s high-resolution spectrum test diagram of the activated persulfate catalyst and natural coal prepared in Example 1 is shown;

[0026] Figure 5 The fully automatic physical adsorption test diagram of the activated persulfate catalyst and natural coal prepared in Example 1 is shown;

[0027] Figure 6 The Raman spectrum test diagram of the activated persulfate catalyst and natural coal prepared in Example 1 is shown;

[0028] Figure 7 A comparison chart of the removal of sulfadiazine in Example 5 of the present disclosure and Comparative Examples 1 to 3 is shown;

[0029] Figure 8 A comparison chart showing the removal of sulfadiazine in different water matrices by Examples 5 to 7 of the present disclosure is shown;

[0030] Fig. 9 A comparison chart showing the removal of sulfamethoxazole (SMX), sulfachloropyridazine (SCP), tetracycline (TC), phenol, and bisphenol A (BPA) according to Examples 8 to 12 of the present disclosure is shown;

[0031] Fig.10 A comparison diagram of the removal of sulfadiazine according to Examples 5, 13 to 15 of the present disclosure is shown;

[0032] Fig.11 A comparative graph showing the removal of sulfadiazine after catalyst recovery of activated persulfate according to Example 16 of the present disclosure. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0034] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0035] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0036] Advanced oxidation technology (AOP) based on persulfate can produce free radicals and non-free radicals. It is an efficient and inexpensive method for degrading antibiotics in water, and has broad application prospects in the field of sewage treatment. The key to activating persulfate technology to produce free radicals and non-free radicals is the catalyst. Among them, precious metal catalysts have high activation efficiency, but their cost is high; metal-based catalysts have metal dissolution, and metal-based catalysts are prone to agglomeration during the persulfate activation process, making the active sites insufficient; the performance of carbon catalysts in activating persulfate is lower than that of metal catalysts.

[0037] During the research process, it was found that nitrogen doping can improve the catalytic activity of carbon materials, but its improvement on catalytic activity is limited; metal doping can not only form new active sites in carbon-nitrogen catalysts and improve the performance of activated persulfate, but also produce high-valent metal oxygen species, such as high-valent iron oxygen species, high-valent cobalt oxygen species, high-valent manganese oxygen species, etc.; C=O and graphitic nitrogen in amorphous carbon-nitrogen structures can serve as active sites, and the metal-N in metal-doped carbon-nitrogen catalysts can also be active sites.

[0038] In the process of realizing the concept of the present invention, it was found that, in the case of graphite-like carbon nitride as a nitrogen source and coal as a carbon source, an unexpected technical effect was achieved by preparing a catalyst for activated persulfate by a simple calcination method.

[0039] Specifically, according to an embodiment of one aspect of the present disclosure, a method for preparing an activated persulfate catalyst is provided, comprising: calcining a mixture of graphite-like carbon nitride and coal to obtain an activated persulfate catalyst.

[0040] According to the embodiments of the present disclosure, graphite-like carbon nitride is a material with a two-dimensional layered structure, which is abundant in source and simple to prepare, and has good physical and chemical stability. The coal in the above embodiments can be natural coal or pre-treated coal, which is mainly composed of elements such as carbon, hydrogen, oxygen, silicon and metals, wherein the metal content is generally between 0.5% and 5.91%.

[0041] According to the embodiments of the present disclosure, a catalyst for activated persulfate is prepared by a simple calcination method using graphite-like carbon nitride as a nitrogen source and coal as a carbon source, thereby solving the problem of catalytic inertness of coal, having a high yield, and can be used directly without further purification. The preparation process is simple, the reaction conditions are universal, the catalyst has a high application value, and is convenient for industrial production.

[0042] The catalyst for activating persulfate provided in the embodiments of the present disclosure has a high specific surface area, rich pores, and a high degree of defects. It fully utilizes amorphous carbon in natural coal and metals in coal, and can form active sites such as graphite N, pyridine N, pyrrole N, metal-N, C=O, etc. to activate persulfate to produce a variety of active species, such as O2 •- , 1 O2 and high-valent metal oxygen species, etc., thereby degrading antibiotics.

[0043] According to an embodiment of the present disclosure, the calcination temperature is 500-800°C, preferably 600-800°C, and the calcination time is 2-4h. Specifically, the calcination temperature can be 500°C, 600°C, 650°C, 700°C, 750°C or 800°C, preferably 600°C; the calcination time can be 2h, 2.5h, 3h, 3.5h or 4h, preferably 2h.

[0044] According to the embodiments of the present disclosure, the appropriate calcination temperature is conducive to efficiently obtaining a catalyst for activating persulfate with excellent performance. Since coal is mainly composed of condensed aromatic rings and heteroatom aromatic rings, and contains functional groups such as phenolic hydroxyl and carboxyl, dehydroxylation can occur at around 600°C, and the structure changes at the same time, and the required active sites can be obtained at a lower temperature, and the maximum number can be achieved. Therefore, the present disclosure can prepare a catalyst for activating persulfate with excellent performance at 600°C.

[0045] According to an embodiment of the present disclosure, calcination is performed under a protective atmosphere.

[0046] According to an embodiment of the present disclosure, the protective atmosphere may be one or more of nitrogen, helium, neon, argon, krypton and xenon.

[0047] According to the embodiments of the present disclosure, the protective atmosphere can isolate the mixture of graphite-like carbon nitride and coal from the air, thereby preventing the mixture of graphite-like carbon nitride and coal from reacting with oxygen to reduce the catalyst yield.

[0048] According to the embodiments of the present disclosure, the heating rate of calcination is 2~8℃ / min, preferably 4~6℃ / min, specifically 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min or 8℃ / min, preferably 5℃ / min.

[0049] According to an embodiment of the present disclosure, the mass ratio of graphite-like carbon nitride to coal is (0.5-3): 1, preferably (1-2.5): 1. Specifically, the mass ratio of graphite-like carbon nitride to coal can be 0.5: 1, 1: 1, 1.5: 1, 2: 1, 2.5: 1 or 3: 1, preferably 2: 1.

[0050] According to the embodiments of the present disclosure, a suitable mass ratio of graphite-like carbon nitride to coal can improve the catalyst performance of activated persulfate while ensuring economic benefits.

[0051] According to an embodiment of the present disclosure, the coal is natural coal or pre-treated natural coal.

[0052] According to an embodiment of the present disclosure, the natural coal is one or more of coking coal, anthracite, sub-bituminous coal, bituminous coal or lignite.

[0053] According to an embodiment of the present disclosure, natural coal may be coal mined from underground without any processing.

[0054] According to an embodiment of the present disclosure, the pre-treated natural coal may be natural coal that has been ball-milled and screened. The particle size of the pre-treated natural coal may be below 200 meshes, so that it can be fully mixed with graphite-like carbon nitride to form a mixture of graphite-like carbon nitride and coal.

[0055] According to another embodiment of the present disclosure, there is provided a method for preparing a catalyst for activating persulfate, comprising the following steps:

[0056] pre-treating natural coal to obtain pre-treated natural coal;

[0057] The pretreated natural coal is mixed with graphite-like carbon nitride, and ground to obtain a mixture of graphite-like carbon nitride and coal;

[0058] The mixture of graphite-like carbon nitride and coal is calcined to obtain an activated persulfate catalyst.

[0059] According to an embodiment of another aspect of the present disclosure, a catalyst for activating persulfate prepared by the above preparation method is provided.

[0060] According to an embodiment of another aspect of the present disclosure, there is provided use of the above-mentioned catalyst for activating persulfate in degrading antibiotics in water.

[0061] The catalyst for activating persulfate provided in the embodiments of the present disclosure improves the inertness of coal-activated persulfate, can accelerate the production of active substances by persulfate to efficiently degrade antibiotics in water, and has the advantages of high degradation rate, fast reaction rate, strong environmental adaptability, good stability and environmental friendliness.

[0062] According to an embodiment of the present disclosure, a catalyst for activating persulfate and persulfate are added to water containing antibiotics to achieve degradation of the antibiotics in the water.

[0063] According to an embodiment of the present disclosure, the mass ratio of the catalyst for activating persulfate to the persulfate is 1:(0.6-2.4), preferably 1:(1.0-2.0). Specifically, the mass ratio of the catalyst for activating persulfate to the persulfate can be 1:0.6, 1:1.0, 1:1.2, 1:1.5, 1:1.8, 1:2.0 or 1:2.4, preferably 1:1.2.

[0064] According to an embodiment of the present disclosure, the mass ratio of antibiotics to persulfate in water is 1:(12-48), preferably 1:(18-40), and further preferably 1:(20-35). Specifically, the mass ratio of antibiotics to persulfate in water can be 1:12, 1:15, 1:18, 1:20, 1:24, 1:30, 1:35, 1:40, 1:45 or 1:48, preferably 1:24.

[0065] According to the embodiments of the present disclosure, excessive use of the catalyst for activating persulfate and persulfate will increase the economic cost, while too little use will affect the effect of removing antibiotics.

[0066] According to an embodiment of the present disclosure, the initial pH of the water containing antibiotics is 3 to 11, preferably 3 to 9. Specifically, the initial pH of the water containing antibiotics can be 3, 4, 5, 6, 7, 8, 9, 10 or 11, preferably 6.

[0067] According to an embodiment of the present disclosure, the antibiotic is one or more of tetracycline, chlortetracycline, oxytetracycline, ciprofloxacin, sulfamethoxazole, sulfachloropyridazine, sulfadiazine, sulfa, sulfamethazine and bisphenol A, and sulfadiazine is selected.

[0068] According to an embodiment of the present disclosure, the persulfate may be one or more of KHSO5•0.5KHSO4•0.5K2SO4, KHSO4, preferably KHSO5•0.5KHSO4•0.5K2SO4.

[0069] According to the embodiments of the present disclosure, the catalyst for activating persulfate can be reused after washing and drying.

[0070] According to an embodiment of the present disclosure, the drying temperature may be 50-100° C., preferably 60-90° C. Specifically, the drying temperature may be 50° C., 60° C., 70° C., 80° C., 90° C. or 100° C.

[0071] The activated persulfate catalyst provided in the embodiments of the present disclosure can be reused after washing and drying, and the degradation rate can still be maintained at a high level, which not only reduces the use cost of the activated persulfate catalyst, but is also environmentally friendly.

[0072] The following lists a number of specific embodiments to illustrate the technical solution of the present invention in detail. It should be noted that the specific embodiments below are only used for illustration and are not used to limit the present invention.

[0073] Example 1

[0074] This embodiment provides a method for preparing a catalyst for activating persulfate, comprising the following steps:

[0075] (1) The coking coal from Pangpangta is ball-milled and sieved to obtain natural coal with a mesh size of less than 200.

[0076] (2) 2 g of graphite-like carbon nitride and 1 g of natural coal were mixed, ground evenly, placed in a covered corundum crucible, and calcined in a nitrogen atmosphere at a temperature of 600 °C and a heating rate of 5 °C / min; the calcination time was 2 h, and the mixture was cooled to room temperature to obtain 1.391 g of an activated persulfate catalyst, referred to as C-CN600.

[0077] The characterization test analysis of the activated persulfate catalyst (C-CN600) prepared above is as follows:

[0078] (1) The morphology of the prepared catalyst was observed using a scanning electron microscope (SEM, Thermo scientific Apreo 2C, USA). Figure 1 The SEM test picture shown. Figure 1 It can be observed that the morphology of C-CN600 is a lamellar structure.

[0079] (2) The functional group structures of natural coal and C-CN600 were characterized by Fourier transform infrared spectroscopy (FTIR, IRAffinity-1S, SHIMADZU, Japan). Figure 2 The FTIR test graph shown. Figure 2 The analysis results show that compared with coal, C-CN600 has a -1 There are CN / CO at 3421 cm -1 There is a -OH functional group at the position, and the results indicate that C-CN600 was successfully prepared.

[0080] (3) The elemental composition of natural coal and C-CN600 was analyzed by ESCALAB 250X X-ray photoelectron spectroscopy (XPS) (ThermoFischer, USA). Figure 3 The XPS test graph shown in Figure 2 is shown in Figure 2. The N 1s high-resolution spectrum of natural coal and C-CN600 is detected, and the following is obtained: Figure 4 High-resolution spectrum test chart shown.

[0081] Depend on Figure 3 and Figure 4 Analysis shows that compared with natural coal, the N content of C-CN600 is significantly increased, and metal-N, pyridinic N, pyrrolic N, graphitic N and oxidized N sites are also formed, giving it higher catalytic activity.

[0082] (4) The specific surface area, total pore volume and pore size distribution of the catalysts of coal and activated persulfate were analyzed using the ASAP 2460 fully automatic physical adsorption instrument (BET model proposed by Brunauer, Emmett and Teller). Figure 5 The BET test diagram shown. Figure 5 It can be seen that the specific surface area of ​​the activated persulfate catalyst (75.36 m 2 / g) is much higher than natural coal (3.11 m 2 / g).

[0083] (5) Using a DXR3 laser confocal Raman spectrometer (Raman), Raman spectroscopy was performed to obtain the following Figure 6 The Raman test diagram shown. Figure 6 Analysis shows that Raman spectroscopy shows that I D / I G is 1.11, and I D / I G is 0.76, indicating that C-CN600 contains abundant defect sites, which makes it have high catalytic activity.

[0084] Example 2

[0085] This embodiment provides a method for preparing an activated persulfate catalyst. The steps are similar to those of Example 1, except that the calcination temperature is 500° C., and 2.32 g of an activated persulfate catalyst is prepared, referred to as C-CN500.

[0086] Example 3

[0087] This embodiment provides a method for preparing an activated persulfate catalyst. The steps are similar to those of Example 1, except that the calcination temperature is 700° C., and 1.267 g of an activated persulfate catalyst is prepared, referred to as C-CN700.

[0088] Example 4

[0089] This embodiment provides a method for preparing an activated persulfate catalyst. The steps are similar to those of Example 1, except that the calcination temperature is 800° C., and 1.065 g of an activated persulfate catalyst is prepared, referred to as C-CN800.

[0090] Example 5

[0091] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was selected to conduct an experiment to remove sulfadiazine (SDZ) in pure water, as follows:

[0092] In a 5 mg / L SDZ solution, 0.1 g / L activated persulfate catalyst (C-CN600) and 0.4 mM persulfate (PMS) were added to trigger the test. Samples were taken at regular intervals and then filtered with a 0.22µm filter membrane. Sodium thiosulfate was added to terminate the reaction, and the collected solution was analyzed for SDZ concentration by HPLC.

[0093] Example 6

[0094] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing sulfadiazine (SDZ) from tap water. The specific process was referred to Example 5, except that the pure water in Example 5 was replaced with an equal volume of tap water.

[0095] Example 7

[0096] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing sulfadiazine (SDZ) from tap water. The specific process was similar to that in Example 5, except that the pure water in Example 5 was replaced with an equal volume of lake water.

[0097] Example 8

[0098] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing sulfamethoxazole (SMX) from pure water. The experimental process was similar to that of Example 5, except that SDZ was replaced with an equal weight of SMX.

[0099] Example 9

[0100] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing sulfachloropyridazine (SCP) from pure water. The experimental process was similar to that of Example 5, except that SDZ was replaced with an equal weight of SCP.

[0101] Example 10

[0102] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing tetracycline (TC) from pure water. The experimental process was similar to that of Example 5, except that SDZ was replaced with an equal weight of TC.

[0103] Embodiment 11

[0104] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was selected to conduct an experiment on removing phenol from pure water. The experimental process was similar to that of Example 5, except that SDZ was replaced with an equal weight of phenol.

[0105] Example 12

[0106] In this example, the activated persulfate catalyst (C-CN600) prepared in Example 1 was used to conduct an experiment on removing bisphenol A (BPA) from pure water. The experimental process was similar to that of Example 5, except that SDZ was replaced with an equal weight of BPA.

[0107] Example 13

[0108] In this example, the activated persulfate catalyst (C-CN500) prepared in Example 2 was selected to conduct an experiment on removing sulfadiazine (SDZ) from pure water. The specific process was referred to Example 5, except that C-CN600 was replaced by an equal weight of C-CN500.

[0109] Embodiment 14

[0110] In this example, the activated persulfate catalyst (C-CN700) prepared in Example 3 was selected to conduct an experiment on removing sulfadiazine (SDZ) from pure water. The specific process was referred to Example 5, except that C-CN600 was replaced by an equal weight of C-CN700.

[0111] Embodiment 15

[0112] In this example, the activated persulfate catalyst (C-CN800) prepared in Example 4 was selected to conduct an experiment on removing sulfadiazine (SDZ) from pure water. The specific process was referred to Example 5, except that C-CN600 was replaced with an equal weight of C-CN800.

[0113] Example 16

[0114] In this example, the coal-derived carbon-nitrogen catalyst (C-CN600) recovered in Example 5 was selected to perform an activation persulfate test to remove SDZ from water. The specific test process was referred to Example 5, and a total of 4 recovery and tests were performed.

[0115] The recycling process is as follows: washing C-CN600 with deionized water and ethanol in sequence, filtering, and drying at 60° C. to obtain recycled C-CN600.

[0116] Comparative Example 1

[0117] This comparative example is a test for removing sulfadiazine (SDZ) from pure water with reference to Example 5, except that no catalyst (C-CN600) for activating persulfate is added in this comparative example.

[0118] Comparative Example 2

[0119] This comparative example is a test for removing sulfadiazine (SDZ) from pure water with reference to Example 5, except that persulfate (PMS) is not added in this comparative example.

[0120] Comparative Example 3

[0121] This comparative example is to conduct an experiment of removing sulfadiazine (SDZ) from pure water with reference to Example 5, except that the catalyst (C-CN600) for activating persulfate in Example 5 is replaced by an equal weight of natural coal.

[0122] The following are relevant test data of the embodiments of the present disclosure:

[0123] Figure 7 The comparison diagram of the removal of sulfadiazine by Example 5 and Comparative Examples 1 to 3 of the present disclosure is shown. Figure 7Analysis shows that the removal rates of SDZ by PMS (Comparative Example 1), C-CN600 (Comparative Example 2) and natural coal / PMS (Comparative Example 3) are all lower than 5%. The oxidation capacity of PMS alone for SDZ is low, the adsorption performance of C-CN600 for SDZ is limited, and natural coal cannot effectively activate PMS to degrade SDZ. When C-CN600 and PMS are added at the same time (Example 5), 92.8% of SDZ can be removed in 20 minutes. The activation effect of C-CN600 on PMS is much greater than that of natural coal.

[0124] Figure 8 The comparison diagram of the removal of sulfadiazine in different water matrices by Examples 5 to 7 of the present disclosure is shown. Figure 8 Analysis shows that in pure water (Example 5), tap water (Example 6) and lake water (Example 7), the removal of SDZ in 20 min was 96.73%, 81.72% and 56.54%, respectively. Since tap water and lake water contain inorganic anions such as carbonates and phosphates and natural organic matter, they not only quench the active species of the reaction system, but also competitively consume persulfate. Therefore, the removal effect of sulfadiazine in tap water and lake water is slightly poor, but C-CN600 / PMS still has a certain adaptability to the water environment.

[0125] Fig. 9 A comparison chart showing the removal of sulfamethoxazole (SMX), sulfachloropyridazine (SCP), tetracycline (TC), phenol and bisphenol A (BPA) according to Examples 8 to 12 of the present disclosure is shown. Fig. 9 The analysis showed that C-CN600 activated PMS had an excellent removal rate for antibiotics, among which the removal rates for SCP, TC, phenol and BPA were all over 90%, and the removal rate for SMX was 81.72%.

[0126] Fig.10 A comparison chart of the removal of sulfadiazine according to Examples 5, 13 to 15 of the present disclosure is shown. Fig.10 Analysis shows that increasing the calcination temperature will increase the reaction rate of SDZ removal by activated persulfate catalyst.

[0127] ESCALAB 250X X-ray photoelectron spectroscopy (X-ray photoecectron spectroscopy, XPS) (ThermoFischer, USA) was used to detect the N 1s high-resolution spectrum of C-CN600, C-CN700, and C-CN800, and the content of each functional group was analyzed as shown in Table 1. From the analysis in Table 1, it can be seen that C-CN600, C-CN700, and C-CN800 have a higher content of active sites, among which C-CN600 and C-CN800 have a higher content of metal-N and graphite N.

[0128] Table 1

[0129]

[0130] Fig.11 A comparison diagram of the removal of sulfadiazine after catalyst recovery of activated persulfate in Example 16 of the present disclosure is shown, Fig.11 The results include the first use of C-CN600 to activate persulfate to remove SDZ from water and the 1st to 4th recycling of C-CN600 to activate persulfate to remove SDZ from water. Fig.11 The analysis shows that the catalytic performance of coal-derived carbon and nitrogen is less affected and can be recycled.

[0131] Through the embodiments disclosed herein, the preparation process of the coal-derived carbon-nitrogen catalyst uses natural coal as the carbon source and nitrogen-rich graphite-like carbon nitride as the nitrogen source. The target catalyst is synthesized by one-step pyrolysis. It can be used directly without further purification. The synthesis process is simple, the reaction conditions are universal, and it has high application value. Compared with natural coal, coal-derived carbon-nitrogen forms new sites such as graphite N, pyridine N, pyrrole N, and metal-N, and the degree of defects is much higher than that of natural coal. Coal-derived carbon-nitrogen changes the inertness of natural coal in activating persulfate. Coal-derived carbon-nitrogen can accelerate persulfate to produce active species to efficiently degrade antibiotics in water, and has the advantages of high antibiotic degradation rate, strong environmental adaptability, and good stability.

[0132] It should be noted that the preparation method of the coal-derived carbon-nitrogen catalyst provided in the embodiments of the present disclosure and its application in activating persulfate to degrade antibiotics in water also have at least one of the following effects and advantages:

[0133] (1) The coal-derived carbon-nitrogen catalyst disclosed in the present invention is prepared by a one-step pyrolysis method, the synthesis process is simple, the reaction conditions are universal, and it has high application value.

[0134] (2) The coal-derived carbon-nitrogen catalyst prepared in the present disclosure is environmentally friendly, has a high specific surface area, rich pores, and forms new sites such as defects, pyridinic N, pyrrolic N, graphitic N, carbonyl, and metal-N. Coal-derived carbon-nitrogen catalyst activates persulfate to produce O2 •- As well as high-valent metal oxygen species and 1 O2, effectively removes antibiotics from water, and can effectively activate persulfate in a wide pH range.

[0135] (3) The coal-derived carbon-nitrogen catalyst prepared in the present invention also has good recyclability.

[0136] The above is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made to the technical method by any technician familiar with the art within the spirit and principle of the present disclosure is still included in the protection scope of the technical solution of the present disclosure.

Claims

1. A method for preparing a catalyst for activated persulfate, characterized in that: The method comprises: The mixture of graphite-like carbon nitride and coal is calcined to obtain the activated persulfate catalyst.

2. The preparation method according to claim 1, characterized in that: The calcination temperature is 500-800° C. and the calcination time is 2-4 hours.

3. The preparation method according to claim 2, characterized in that: The calcination is carried out under a protective atmosphere; The heating rate of the calcination is 2-8°C / min.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the graphite-like carbon nitride to coal is (0.5~3):

1.

5. The preparation method according to any one of claims 1 to 4, characterized in that The coal is natural coal or pre-treated natural coal; The natural coal is one or more of coking coal, anthracite, sub-bituminous coal, bituminous coal or lignite.

6. A catalyst for activating persulfate obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the persulfate activated catalyst according to claim 6 in degrading antibiotics in water.

8. The use according to claim 7, characterized in that: adding the catalyst for activating persulfate and persulfate to water containing antibiotics to achieve degradation of the antibiotics in the water; The mass ratio of the catalyst for activating persulfate to the persulfate is 1:(0.6-2.4); The mass ratio of the antibiotic in the water to the persulfate is 1:(12-48); The initial pH of the antibiotic-containing water is 3-11.

9. The use according to claim 7 or 8, characterized in that: The antibiotic is one or more of tetracycline, chlortetracycline, oxytetracycline, ciprofloxacin, sulfamethoxazole, sulfachloropyridazine, sulfadiazine, sulfa, sulfamethazine and bisphenol A.

10. The use according to claim 7 or 8, characterized in that: The activated persulfate catalyst can be reused after being washed and dried.

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