A photocatalytic material for deep treatment of antibiotics in landfill leachate

Abstract

The present invention provides a photocatalytic material for deep treatment of antibiotics in landfill leachate. The photocatalytic material is a nano heterojunction photocatalytic material, which is mainly composed of a composite of nano rod-shaped bismuth oxide, nano spherical cobalt oxide and boron nitride nanosheets. The photocatalytic material of the present invention has stable photocatalytic performance, strong heterojunction stability in a water environment, and high efficiency in degradation of norfloxacin. The photocatalytic material can deeply treat antibiotics in landfill leachate and is highly efficient and circularly economical.

Description

Technical Field

[0001] The invention belongs to the field of deep treatment of antibiotic wastewater and photocatalytic treatment, and specifically relates to a photocatalytic material for deep treatment of antibiotics in landfill leachate. Background Art

[0002] In recent years, antibiotics have attracted widespread attention from the whole society as one of the important reasons for the increase of pathogen resistance and the generation of ARGs (Antibiotics Resistance Genes, ARGs). The "Action Plan for the Control of New Pollutants (Draft for Comments)" also includes antibiotics in the first list of key controlled new pollutants. Compared with municipal wastewater and natural water bodies, landfill leachate has a higher concentration of antibiotics. The high-content antibiotics remaining in standardized landfills mainly enter the surrounding environment through the tail water discharge of leachate treatment facilities, posing potential risks to the surrounding ecological environment. The discharge of landfill leachate wastewater has become an important source of antibiotics in the environment that cannot be ignored. Therefore, it is urgent to find a simple and efficient method to remove antibiotics from leachate.

[0003] In recent years, photocatalytic technology has attracted international attention as an emerging means of pollution prevention and control. Compared with traditional photocatalysts, bismuth-based photocatalysts can absorb a large amount of visible light in the solar spectrum and make full use of solar energy to catalytically degrade pollutants. They have many advantages, such as low production cost, high photostability, narrow band gap, anti-photocorrosion, and large specific area / pore volume. However, they also have high photogenerated electron-hole recombination rate and low photocatalytic efficiency. Among them, Bi2O3 has been a material that has attracted much attention in recent years due to its good conductivity, thermal properties and narrow band gap (2.8eV). However, the photocatalytic activity of pure Bi2O3 is still insufficient for application. To solve this problem, strategies such as doping, preparing composite materials with other semiconductor materials, or establishing heterojunctions are used to improve the photocatalytic activity of Bi2O3, such as Bi2O3 / Co3O4, α-Bi2O3 / β-Ni(OH)2, Bi2O3 / Bi2WO6, etc., all of which have shown excellent photocatalytic performance.

[0004] Co3O4 is attractive for photocatalytic treatment of wastewater contaminated by organic pollutants due to its narrow band gap in the range of 1.2-2.1 eV. In addition, Co3O4 is introduced as a co-catalyst into heterojunction photocatalysts or photoelectrochemical catalysts, which can promote the oxidation of water and the separation of photogenerated electron-hole pairs.

[0005] Boron nitride (BN), a graphene analog, is a non-metallic semiconductor with a two-dimensional (2D) structure similar to g-C3N4 and graphene. This 2D structure has a high specific surface area, abundant reaction sites, and a short bulk charge diffusion length, which is very beneficial for improving photocatalytic activity. Previous studies have shown that photocatalysts composed of BN, such as BN / AgBr and BN / Cu2O, exhibit better photocatalytic activity because BN inhibits the rapid recombination of photoinduced electron-hole pairs during photocatalysis. Although there are many studies on Bi2O3 / Co3O4 composites, research on constructing BN / Bi2O3 / Co3O4 heterojunctions using BN as a charge transport medium has not yet been carried out, and its application in the removal of antibiotics in leachate is of great significance. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a visible light catalytic material for deep treatment of antibiotics in landfill leachate.

[0007] The technical solution of the present invention is: a photocatalytic material for deep treatment of antibiotics in landfill leachate, the photocatalytic material is a nano heterojunction composite material, the nano heterojunction composite material is prepared by compounding BN nano sheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 1 to 10:90 to 99.5:5; wherein the diameter of the nano rod-shaped Bi2O3 is 1000 to 2000nm, the size of the BN nano sheet is 100 to 1000nm, and the diameter of the nano spherical Co3O4 is 50 to 300nm.

[0008] Description: Through the three-phase composite material based on the simultaneous loading of BN nanosheets and nano-spherical Co3O4 on nanorod-like Bi2O3, the BN nanosheets established a charge transfer bridge between the Co3O4 nanospheres and the Bi2O3 nanorods, forming a heterogeneous structure among the three. With the introduction of BN and Co3O4, the three-phase photocatalytic material BN / Bi2O3 / Co3O4 has a wider absorption range for visible light, and the absorption in the ultraviolet and visible light regions is greatly enhanced. This phenomenon helps to improve the visible light photocatalytic activity of the three-phase material, is conducive to the generation of more photogenerated electrons and holes, and improves the transfer efficiency of charge carriers, thereby improving the comprehensive performance of the composite material.

[0009] A method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate comprises the following steps:

[0010] S1. In a ratio of nano-spherical Co3O4 to solvent of 1 g:3 ml, BN nanosheets, nano-rod-shaped Bi2O3 and nano-spherical Co3O4 are added to the solvent step by step at 30-40°C, and the mixture is stirred for 22-25 hours to obtain a mixture;

[0011] S2. After centrifugal separation, filtration, and washing the mixture for multiple times, the mixture is placed in an oven at 55-70° C. and dried for 12 hours to obtain a nano-heterojunction composite material.

[0012] Description: The above method is used to prepare photocatalytic materials, so that Co3O4 nanospheres and BN nanosheets can be dispersed on the surface of Bi2O3, and BN nanosheets are evenly attached to the surface of Bi2O3 to form a relatively uniform surface morphology. The electron conduction ability between the loaded material and graphene is more efficient, and the obtained nano-heterojunction composite material has better catalytic performance.

[0013] Furthermore, the solvent in step S1 is anhydrous ethanol.

[0014] Note: Anhydrous ethanol liquid is used as the solvent because ethanol has good solubility and is cheap and easily available.

[0015] Furthermore, the centrifugal separation parameters in step S2 are: centrifugation at a speed of 3000 to 5000 r / min for 8 to 10 min; and the washing is performed with ultrapure water.

[0016] Note: By processing the above parameters, solid-liquid separation can be achieved better.

[0017] Furthermore, the solvent is a solution prepared by mixing polyetheramine: silane coupling agent: toluene in a mass ratio of 1:1:55-65.

[0018] Note: By using the above solvent, the nano-objects can be dispersed, making the combination of the three nano-objects more uniform. At the same time, it can promote the formation of heterojunctions and reduce agglomeration, thereby improving the composite quality and enhancing the catalytic performance.

[0019] Furthermore, the stepwise adding method and the stirring and mixing process in step S1 are as follows:

[0020] S1-1, firstly, add BN nanosheets and nano-spherical Co3O4 into a solvent, and ultrasonically disperse them for 30 to 50 minutes at an ultrasonic frequency of 30 to 40 KHz to obtain a dispersion of BN nanosheets and nano-spherical Co3O4;

[0021] S1-2. Add the nanorod-shaped Bi2O3 to the dispersion obtained in step S1-1, stir at a stirring speed of 500-800 r / min for 20-24 h, and then perform ultrasonic blending at an ultrasonic frequency of 30-40 kHz for 1-2 h to obtain a mixture.

[0022] Note: Through the stirring treatment by the above method, BN nanosheets and nano-spherical Co3O4 can be evenly dispersed in the solvent to combine first, and then nano-rod-like Bi2O3 is added to make BN nanosheets and nano-spherical Co3O4 fall evenly on the surface of nano-rod-like Bi2O3 to combine, which can make the combination of the three nanomaterials more uniform and reduce the agglomeration of small particles, thereby improving the composite quality and enhancing the catalytic performance.

[0023] Furthermore, the nanorod-shaped Bi2O3 added in step S1-2 is pretreated nanorod-shaped Bi2O3; the pretreatment method is: first, a polyetheramine, a silane coupling agent, and ultrapure water in a mass ratio of 1:1:75-85 are mixed to obtain a treatment agent; then the treatment agent and the nanorod-shaped Bi2O3 are mixed and stirred in a mass ratio of 1:1 for 15-20 minutes, and then filtered and ventilated and dried to obtain the treated nanorod-shaped Bi2O3.

[0024] Description: The nanorod-like Bi2O3 is pretreated by the above method to enhance the adhesion of BN nanosheets and nanospherical Co3O4 on the surface of the nanorod-like Bi2O3, so that the obtained nano-heterojunction composite material has a better catalytic effect.

[0025] Furthermore, the preparation method of the BN nanosheets is:

[0026] 1) Dissolve boric acid and urea in ultrapure water at a ratio of 0.62 g: 28.83 g: 40 mL, place in a 65°C water bath, and stir until dry to obtain a solid;

[0027] 2) The solid obtained in step 1) is heated to 900° C. at a heating rate of 3° C. / min in a N2 atmosphere, and is calcined at a constant temperature for 5 h and then cooled in the furnace to obtain boron nitride nanosheets.

[0028] Description: The BN nanosheets obtained by the above method have a large surface and thin film layer; they can establish a charge transfer bridge between Co3O4 nanospheres and Bi2O3 nanorods, forming a strong heterostructure between the three.

[0029] Furthermore, the preparation method of the nanorod-shaped Bi2O3 is:

[0030] 1) Take a 300 g / L bismuth nitrate pentahydrate solution, add 0.1 mol of bismuth nitrate pentahydrate and 1 ml of dilute nitric acid with a mass fraction of 10% to obtain a pretreatment solution;

[0031] 2) Heat the pretreatment solution in a water bath at 50°C for 2 minutes, then slowly add a 2 mol / L NaOH solution at a mass ratio of bismuth nitrate pentahydrate to NaOH of 3.13:1, and slowly add 5% of the total amount of NaOH solution per minute, and then stir for 30 minutes;

[0032] 3) Filter to obtain a light yellow precipitate, wash the light yellow precipitate three times with distilled water and anhydrous ethanol in turn, and dry the washed precipitate in a drying oven at 80°C for 2 hours to obtain nanorod-shaped Bi2O3.

[0033] Description: The nanorod-shaped Bi2O3 obtained by the above method is regular and uniform, and has the advantages of good crystallinity and high purity.

[0034] A use of an antibiotic photocatalytic material for deep treatment of landfill leachate, wherein the catalytic material is used to degrade the norfloxacin antibiotic in the landfill leachate; the pH value of the leachate is 3-9; the degradation method is: the nano-heterojunction composite material is mixed with the antibiotic-containing leachate and then a catalytic reaction is carried out under visible light for 3 hours.

[0035] Description: Through the use and use of the above-mentioned photocatalytic material, norfloxacin can be efficiently degraded, and the degradation rate can reach 98%.

[0036] The beneficial effects of the present invention are:

[0037] (1) The present invention establishes a charge transfer bridge between Co3O4 nanospheres and Bi2O3 nanorods by simultaneously loading BN nanosheets and nanospherical Co3O4 on nanorod-like Bi2O3, thereby forming a heterogeneous structure among the three. With the introduction of BN and Co3O4, the three-phase photocatalytic material BN / Bi2O3 / Co3O4 has a wider absorption range for visible light, and the absorption in the ultraviolet and visible light regions is greatly enhanced. This phenomenon helps to improve the visible light photocatalytic activity of the three-phase material, is conducive to generating more photogenerated electrons and holes, and improves the transfer efficiency of charge carriers, thereby improving the comprehensive performance of the composite material.

[0038] (2) The present invention prepares photocatalytic materials through the above method, so that Co3O4 nanospheres and BN nanosheets can be dispersed on the surface of Bi2O3, and BN nanosheets are evenly attached to the surface of Bi2O3 to form a relatively uniform surface morphology. The electron conduction ability between the supported material and graphene is more efficient, and the obtained nano-heterojunction composite material has better catalytic performance, which reduces the agglomeration effect between small particles, thereby improving the composite quality and enhancing the catalytic performance.

[0039] (3) The present invention can disperse the nano-objects by using a solvent and pre-treating the nano-rod-like Bi2O3, making the combination of the three nano-objects more uniform and promoting the formation of a heterojunction, thereby improving the composite quality and enhancing the catalytic performance; by pre-treating the nano-rod-like Bi2O3 by the above method, the adhesion effect of BN nanosheets and nano-spherical Co3O4 on the surface of the nano-rod-like Bi2O3 is enhanced, so that the obtained nano-heterojunction composite material has a better catalytic effect.

[0040] (4) The method of the present invention is simple and low in cost, and can degrade 98% of norfloxacin in landfill leachate within 100 minutes. After four cycles of use, the photocatalytic material still exhibits efficient photocatalytic performance, and the degradation efficiency after four cycles still reaches 88.4%, indicating that the photocatalytic performance of the photocatalytic material of the present invention is stable, the heterojunction has strong stability in the water environment, and the degradation efficiency of norfloxacin is high. The photocatalytic material is a composite photocatalytic material that can deeply treat antibiotics in landfill leachate and is efficient and circularly economical. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The XRD diffraction pattern of the photocatalyst obtained in Example 1 of the present invention;

[0042] Figure 2 a in the present invention is a Bi2O3 rod-like structure; b is a BN nanosheet; c is a Co3O4 nanosphere; d is a Co3O4 nanosphere and a BN nanosheet deposited on a Bi2O3 nanorod; e is an EDS analysis diagram; f is a TEM image of Example 1; g is an HRTEM image of Example 1;

[0043] Figure 3 The photocatalytic degradation of norfloxacin by the photocatalysts obtained in Examples 1 to 4 of the present invention under visible light is shown;

[0044] Figure 4 The DRS spectrum and band gap energy diagram of the photocatalyst obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with specific implementation methods to better reflect the advantages of the present invention.

[0046] Example 1

[0047] A photocatalytic material for deep treatment of antibiotics in landfill leachate.

[0048] The photocatalytic material is a nano heterojunction composite material, which is prepared by compounding BN nanosheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 5:95:5; wherein the diameter of the nano rod-shaped Bi2O3 is 1000-2000nm, the size of the BN nanosheet is 100-1000nm, and the diameter of the nano spherical Co3O4 is 50-300nm

[0049] The preparation method comprises the following steps:

[0050] S1. At a ratio of 1 g of nano-spherical Co3O4 to 3 ml of solvent, BN nanosheets, nano-rod-shaped Bi2O3 and nano-spherical Co3O4 are added step by step to 15 ml of solvent at 35°C, and the mixture is stirred and mixed for 24 hours to obtain a mixture; the solvent is a solution prepared by preparing polyetheramine: silane coupling agent: toluene at a mass ratio of 1:1:60;

[0051] S1-1, firstly, BN nanosheets and nano-spherical Co3O4 are added to a solvent, and ultrasonically dispersed for 40 minutes at an ultrasonic frequency of 35KHz to obtain a dispersion of BN nanosheets and nano-spherical Co3O4;

[0052] S1-2, adding the nanorod-shaped Bi2O3 to the dispersion obtained in step S1-1, stirring at a stirring speed of 600 r / min for 22 hours, and then ultrasonically blending at an ultrasonic frequency of 35 KHz for 1.5 hours to obtain a mixture;

[0053] The nanorod-shaped Bi2O3 added in step S1-2 is pretreated nanorod-shaped Bi2O3; the pretreatment method is: firstly, a polyetheramine, a silane coupling agent, and ultrapure water are mixed in a mass ratio of 1:1:75-85 to obtain a treatment agent; then, the treatment agent and the nanorod-shaped Bi2O3 are mixed and stirred in a mass ratio of 1:1 for 18 minutes, and then filtered and ventilated and dried to obtain the treated nanorod-shaped Bi2O3;

[0054] S2, centrifugation, filtration, washing the mixture for multiple times, and drying it in an oven at 65° C. for 12 hours to obtain a nano heterojunction composite material; the centrifugation parameter is 4000 r / min at a speed of 9 minutes; the washing is performed with ultrapure water;

[0055] The preparation method of the BN nanosheet is:

[0056] 1) Dissolve boric acid and urea in ultrapure water at a ratio of 0.62 g: 28.83 g: 40 mL, place in a 65°C water bath, and stir until dry to obtain a solid;

[0057] 2) The solid obtained in step 1) is heated to 900° C. at a heating rate of 3° C. / min in a N2 atmosphere, and is calcined at a constant temperature for 5 hours and then cooled in the furnace to obtain boron nitride nanosheets;

[0058] The preparation method of the nanorod-shaped Bi2O3 is:

[0059] 1) Take a 300 g / L bismuth nitrate pentahydrate solution, add 0.1 mol of bismuth nitrate pentahydrate and 1 ml of dilute nitric acid with a mass fraction of 10% to obtain a pretreatment solution;

[0060] 2) Heat the pretreatment solution in a water bath at 50°C for 2 minutes, then slowly add bismuth nitrate pentahydrate: NaOH at a mass ratio of 3.13:1 to a 2 mol / L NaOH solution at a rate of 5% of the total amount of NaOH solution per minute, and then stir for 30 minutes;

[0061] 3) Filter to obtain a light yellow precipitate, wash the light yellow precipitate three times with distilled water and anhydrous ethanol in sequence, and dry the washed precipitate in a drying oven at 80° C. for 2 h to obtain the target nanorod-shaped bismuth oxide;

[0062] The preparation method of nano-spherical cobalt oxide is as follows:

[0063] First, 0.1M cobalt II and 0.2M cobalt III were dissolved in a 1:1 mixed solvent of ethanol and distilled water in a ratio of 1:1.5; 1ml of hydrogen peroxide was added, and then 2ml of sodium hydroxide was dropped into the cobalt precursor mixture and stirred for 1h; the stirred mixture was transferred to a Teflon-coated autoclave and stored in an oven at 140°C for 8h; the reaction mixture was filtered, dried, and calcined at 500°C for 5h to obtain nano-spherical cobalt oxide.

[0064] Example 2

[0065] The difference between this embodiment and embodiment 1 is that the raw material components are different. The nano heterojunction composite material is prepared by compounding BN nano sheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 1:99:5.

[0066] Example 3

[0067] The difference between this embodiment and embodiment 1 is that the raw material components are different. The nano heterojunction composite material is prepared by compounding BN nano sheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 10:90:5.

[0068] Example 4

[0069] The difference between this embodiment and embodiment 1 is that the raw material components are different. The nano heterojunction composite material is prepared by compounding BN nano sheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 2.5:97.5:5.

[0070] Example 5

[0071] The difference between this embodiment and embodiment 1 is that the condition parameters in step S1 are different. At 30° C., BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4 are added to 15 ml of solvent and stirred and mixed for 22 hours to obtain a mixture; the solvent is anhydrous ethanol liquid.

[0072] Example 6

[0073] The difference between this embodiment and embodiment 1 is that the condition parameters in step S1 are different. At 40° C., BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4 are added to 15 ml of solvent and stirred and mixed for 25 hours to obtain a mixture; the solvent is anhydrous ethanol liquid.

[0074] Example 7

[0075] The difference between this embodiment and embodiment 1 is that the condition parameters in step S2 are different, the nano-heterojunction composite material is placed in an oven at 55° C. for 12 hours to obtain the nano-heterojunction composite material; the centrifugal separation is performed at a speed of 5000 r / min for 8 minutes; and the washing is performed with ultrapure water.

[0076] Example 8

[0077] The difference between this embodiment and embodiment 1 is that the condition parameters in step S2 are different, the nano-heterojunction composite material is placed in an oven at 70° C. for 12 hours to obtain the nano-heterojunction composite material; the centrifugal separation is performed at a speed of 3000 r / min for 10 minutes; and the washing is performed with ultrapure water.

[0078] Example 9

[0079] The difference between this embodiment and embodiment 1 is that the solvent is anhydrous ethanol liquid.

[0080] Example 10

[0081] The difference between this embodiment and embodiment 1 is that the solvent is a solution prepared by mixing polyetheramine: silane coupling agent: toluene in a mass ratio of 1:1:55.

[0082] Embodiment 11

[0083] The difference between this embodiment and embodiment 1 is that the solvent is a solution prepared by mixing polyetheramine: silane coupling agent: toluene in a mass ratio of 1:1:65.

[0084] Example 12

[0085] The difference between this embodiment and embodiment 1 is that the time parameters of steps S1-1 and S1-2 are different. In step S1-1, ultrasonic dispersion is performed for 30 minutes, and in step S1-2, stirring is performed for 24 hours and ultrasonic blending is performed for 1 hour.

[0086] Embodiment 13

[0087] The difference between this embodiment and embodiment 1 is that the time parameters of steps S1-1 and S1-2 are different. In step S1-1, ultrasonic dispersion is performed for 50 minutes, and in step S1-2, stirring is performed for 20 hours and ultrasonic blending is performed for 2 hours.

[0088] Embodiment 14

[0089] The difference between this embodiment and embodiment 1 is that the ultrasonic frequency and stirring speed are different. In step S1-1, the ultrasonic frequency is 40KHz, and in step S1-2, the stirring speed is 800r / min and the ultrasonic frequency is 30KHz.

[0090] Embodiment 15

[0091] The difference between this embodiment and embodiment 1 is that the ultrasonic frequency and stirring speed are different. In step S1-1, the ultrasonic frequency is 30KHz, and in step S1-2, the stirring speed is 500r / min and the ultrasonic frequency is 40KHz.

[0092] Example 16

[0093] The difference between this embodiment and embodiment 1 is that the condition parameters are different. The treatment agent is prepared by using polyetheramine: silane coupling agent: ultrapure water in a mass ratio of 1:1:75; then the treatment agent and nanorod-shaped Bi2O3 are mixed and stirred in a mass ratio of 1:1 for 20 minutes.

[0094] Embodiment 17

[0095] The difference between this embodiment and embodiment 1 is that the condition parameters are different. The treatment agent is prepared by using polyetheramine: silane coupling agent: ultrapure water in a mass ratio of 1:1:85; then the treatment agent and nanorod-shaped Bi2O3 are mixed and stirred in a mass ratio of 1:1 for 15 minutes.

[0096] Experimental example

[0097] 1. XRD, SEM and TEM spectra of the photocatalytic material obtained in Example 1 were characterized as follows: Figures 1-2 ; Using Example 1 and the DRS spectra and band gap energy diagrams of BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4, respectively, characterize:

[0098] like Figure 4 As shown in , with the introduction of BN and Co3O4, the absorption range of visible light by the photocatalytic material becomes wider, and the absorption in the ultraviolet and visible light regions is greatly enhanced. This phenomenon helps to improve the visible light photocatalytic activity of the nanocomposite material and is conducive to the generation of more photogenerated electrons and holes.

[0099] 2. Using the photocatalytic materials obtained in Examples 1 to 17, an adsorption photocatalytic degradation experiment of norfloxacin was carried out under the irradiation of a xenon lamp; the specific research is as follows:

[0100] The samples were divided into 17 groups. Each group was placed under a xenon lamp with 50 mL of a 10 mg / L norfloxacin aqueous solution. 50 mg of the prepared photocatalytic material was added and stirred in the dark for 30 min to reach adsorption-desorption equilibrium. The light was then turned on for a photocatalytic reaction for 3 h to obtain the degradation rate.

[0101] The results are as follows:

[0102] 1. To explore the effect of the composition of BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4 on the catalytic degradation effect;

[0103] Comparative Example 1: The nanorod-shaped Bi2O3 obtained in Example 1 was subjected to a degradation experiment;

[0104] Comparative Example 2: The nano-spherical cobalt trioxide obtained in Example 1 was subjected to a degradation experiment;

[0105] Comparative Example 3: Using nanorod-shaped Bi2O3 and BN nanosheets as raw materials to carry out the treatment of Example 1, a two-phase photocatalyst was obtained for degradation experiment;

[0106] Comparative Example 4: Using nanorod-shaped Bi2O3 and nanospherical cobalt oxide as raw materials to carry out the treatment of Example 1, a two-phase photocatalyst was obtained for degradation experiment;

[0107] Comparative Example 5: Using BN nanosheets and nano-spherical cobalt oxide as raw materials to carry out the treatment of Example 1, a two-phase photocatalyst was obtained for degradation experiment;

[0108] Comparative Example 6: Commercially available nanorod-shaped Bi2O3 / BN nanosheets and nanospherical cobalt oxide were used as raw materials to carry out the treatment of Example 1 to obtain a photocatalyst for degradation experiments;

[0109] Examples 1 to 4 and comparative examples 1 to 5 are compared as follows:

[0110] Table 1 Effect of different amounts of BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4 on catalytic degradation;

[0111]

[0112]

[0113] From Table 1 and Figure 3 It can be seen that the photocatalytic material in Example 1 shows the best photocatalytic performance, and the degradation rate of norfloxacin can reach 98%, indicating that the photocatalytic material in Example 1 can be used for the efficient treatment of organic pollutants in water; by comparing Examples 1 to 4, it can be seen that the proportioning components in Example 1 are optimal; by comparing Example 1 and Comparative Examples 1 to 5, it can be seen that the degradation efficiency of Comparative Examples 1 to 3 and Comparative Example 5 is relatively low, and by comparing Comparative Example 4 with Example 1, it can be found that after adding BN, the photocatalytic degradation rate is significantly improved; by comparing Example 1 with Comparative Example 6, it can be found that the raw material prepared by the method of Example 1 is more preferred.

[0114] 2. Explore the effects of different parameters in the preparation process on the catalytic degradation effect;

[0115] Example 1, Examples 5 to 8, and Examples 12 to 17 were used for experimental comparison, and the results are shown in Table 2 below:

[0116] Table 2 Effect of different condition parameters on catalytic degradation

[0117]

[0118]

[0119] It can be seen from Table 2 that different temperatures, stirring times and centrifugal parameters all affect the obtained photocatalytic effect. By comparing Example 1 with Examples 5 to 8, it can be seen that the condition parameters of Example 1 are better. By comparing Example 1 with Examples 12 to 15, it can be seen that the time of steps S1-1 and S1-2, the ultrasonic frequency and stirring parameters all affect the obtained photocatalytic effect, among which Example 1 is better.

[0120] 3. Investigate the effect of solvent composition on the catalytic degradation effect

[0121] Using Example 1 and Examples 9 to 11 as experimental comparisons, the results are shown in Table 3 below:

[0122] Table 3 Effect of different solvents on catalytic degradation

[0123] parameter Degradation rate % Example 1 98 Example 9 91 Example 10 95 Embodiment 11 96

[0124] It can be seen from Table 3 that different solvents have an effect on the catalytic degradation performance of the prepared photocatalytic material. By comparing Example 1 and Example 9, it can be seen that Example 1 is better, indicating that the solvent used in Example 1 is more preferred. By comparing Example 1, Example 10 and Example 11, it can be seen that the solvent preparation component of Example 1 is better.

[0125] 3. Investigate the effect of pretreatment preparation of nanorod-shaped Bi2O3 on the catalytic degradation effect

[0126] Comparative Example 7: The nanorod-shaped Bi2O3 was not pretreated, and the rest was the same as Example 1;

[0127] Comparative Example 8: Step S1-1 and step S1-2 were not set in the preparation process, and the remaining processes were the same as those in Example 1;

[0128] Example 1 and Examples 16 to 17 were used as experimental comparisons, and the results are shown in Table 4 below:

[0129] Table 4 Effect of different nanorod-shaped Bi2O3 pretreatments on catalytic degradation

[0130] parameter Degradation rate % Example 1 98 Example 16 96 Embodiment 17 94 Comparative Example 7 90 Comparative Example 8 87

[0131] It can be seen from Table 4 that whether or not the nanorod-like Bi2O3 is pretreated has an impact on the catalytic degradation performance of the prepared photocatalytic material. By comparing Example 1 and Comparative Example 7, it can be seen that Example 1 pretreated with nanorod-like Bi2O3 is more preferred; by comparing Example 1 and Comparative Example 8, it can be seen that the catalytic degradation performance of the photocatalytic material prepared by the treatment of step S1-1 and step S1-2 in Example 1 is significantly improved; by comparing Example 1, Example 16 and Example 17, it can be seen that the treatment liquid component ratio and stirring time of Example 1 are better.

Claims

1. A photocatalytic material for deep treatment of antibiotics in landfill leachate, characterized in that: The photocatalytic material is a nano heterojunction composite material, which is prepared by compounding BN nanosheets, nano rod-shaped Bi2O3 and nano spherical Co3O4 in a mass ratio of 1-10:90-99.5:5; wherein the diameter of the nano rod-shaped Bi2O3 is 1000-2000nm, the size of the BN nanosheet is 100-1000nm, and the diameter of the nano spherical Co3O4 is 50-300nm.

2. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 1, characterized in that: The following steps are involved: S1. Add BN nanosheets, nanorod-shaped Bi2O3 and nanospherical Co3O4 into a solvent step by step at 30-40°C, and stir and mix for 22-25h to obtain a mixture; S2. After the mixture is centrifuged, filtered, and washed for multiple times, it is placed in an oven at 55-70° C. and dried for 12 h to obtain a nano-heterojunction composite material.

3. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 2, characterized in that: The solvent in step S1 is anhydrous ethanol.

4. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 2, characterized in that: The centrifugal separation parameters in step S2 are: centrifugation at a speed of 3000-5000 r / min for 8-10 min; and washing with ultrapure water.

5. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 2, characterized in that: The solvent is a solution prepared by mixing polyetheramine: silane coupling agent: toluene in a mass ratio of 1:1:55-65.

6. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 2, characterized in that: The stepwise adding method and stirring and mixing process in step S1 are as follows: S1-1, firstly, BN nanosheets and nano-spherical Co3O4 are added to a solvent, and ultrasonically dispersed for 30-50 minutes at an ultrasonic frequency of 30-40 kHz to obtain a dispersion of BN nanosheets and nano-spherical Co3O4; S1-2. Add the nanorod-shaped Bi2O3 to the dispersion obtained in step S1-1, stir at a stirring speed of 500-800 r / min for 20-24 h, and then perform ultrasonic blending at an ultrasonic frequency of 30-40 kHz for 1-2 h to obtain a mixture.

7. The method for preparing an antibiotic photocatalytic material for deep treatment of landfill leachate according to claim 6, characterized in that: The nanorod-shaped Bi2O3 added in step S1-2 is pretreated nanorod-shaped Bi2O3; the pretreatment method is: first, a polyetheramine, a silane coupling agent, and ultrapure water are mixed in a mass ratio of 1:1:75~85 to obtain a treatment agent; then the treatment agent and the nanorod-shaped Bi2O3 are mixed in a mass ratio of 1:1 and stirred for 15~20 minutes, and then filtered and ventilated and dried to obtain the treated nanorod-shaped Bi2O3.

8. The photocatalytic material for deep treatment of antibiotics in landfill leachate according to claim 1, characterized in that: The preparation method of the BN nanosheet is: 1) Dissolve boric acid and urea in ultrapure water at a ratio of 0.62 g: 28.83 g: 40 mL, place in a 65°C water bath, and stir until dry to obtain a solid; 2) The solid obtained in step 1) is heated to 900°C at a heating rate of 3°C / min in a N2 atmosphere, and is calcined at a constant temperature for 5 hours and then cooled in the furnace to obtain boron nitride nanosheets.

9. The photocatalytic material for deep treatment of antibiotics in landfill leachate according to claim 1, characterized in that: The preparation method of the nanorod-shaped Bi2O3 is: 1) Take a 300 g / L bismuth nitrate pentahydrate solution, add 0.1 mol of bismuth nitrate pentahydrate and 1 mL of dilute nitric acid with a mass fraction of 10% to obtain a pretreatment solution; 2) Heat the pretreatment solution in a water bath at 50°C for 2 minutes, then slowly add a 2 mol / L NaOH solution at a mass ratio of 3.13:1 of bismuth nitrate pentahydrate to NaOH, and add 5% of the total amount of NaOH solution per minute, and then stir for 30 minutes; 3) Filter to obtain a light yellow precipitate, wash the light yellow precipitate three times with distilled water and anhydrous ethanol in turn, and dry the washed precipitate in a drying oven at 80°C for 2 hours to obtain nanorod-shaped Bi2O3.

10. The use of antibiotic photocatalytic materials for deep treatment of landfill leachate according to claim 1, characterized in that: The photocatalytic material is applied to degrade the norfloxacin antibiotic in landfill leachate.

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