Self-template synthesized linear biochar-based bimetallic material as well as preparation method and application thereof

Abstract

The invention discloses a self-template synthesized linear biochar-based bimetallic material as well as a preparation method and application thereof, and belongs to the technical field of carbon materials. The method comprises the following steps: pretreating ganoderma lucidum residues, and pyrolyzing in a nitrogen atmosphere to prepare charcoal; and mixing the prepared biochar with cobalt nitrate and sodium molybdate to prepare CoMoO4 nanoparticles with in-situ growth of the biochar, and then washing and drying to obtain the BC-coated CoMoO4 linear biochar-based bimetallic material. Heterojunctions formed by binding sites of cobalt-molybdenum bimetal and biochar in the material form more defect sites, the synergistic effect of the metal and the micro-nano fibrous biochar is exerted, the degradation rate in the application of catalytic degradation of bisphenol A can reach 98.18% or above, a multiple reaction mechanism with sulfate free radicals is jointly shown, and the photocatalytic degradation of bisphenol A is realized. And the method has higher adaptability and effectiveness for complex pollutants.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon materials, and particularly relates to a self-template synthesized linear biochar-based bimetallic material, a preparation method thereof and an application thereof. Background Art

[0002] The application of biochar in degrading pollutants mainly depends on its high specific surface area, porous structure and surface active functional groups, which can effectively adsorb and catalytically degrade organic pollutants and heavy metals. In the prior art, biochar is often combined with metals such as iron, copper, and zinc to form composite materials to enhance its catalytic performance or adsorption capacity. However, such composite materials have many defects and deficiencies in practical applications. First, the risk of metal leaching is relatively high, which may cause secondary pollution, especially the harm of heavy metals to the ecosystem and human health; second, the composite material may have unstable structure under long-term use or extreme conditions, affecting its degradation efficiency; in addition, the preparation cost is high and the process is complex, which limits its large-scale promotion. Some composite materials have limited degradation effects on specific pollutants, are difficult to cope with complex pollution environments, and are difficult to be efficiently regenerated and recycled after use, increasing the treatment cost. Certain composite materials may also be toxic to microorganisms or plants, destroying the ecological balance; at the same time, the properties of biochar from different sources or preparation processes vary greatly, resulting in unstable properties of the composite material. At present, the long-term environmental impact and ecological risk of metal-biochar composite materials are insufficiently studied, and it is difficult to comprehensively evaluate their safety. Therefore, although such materials show potential in pollutant degradation, further research is still needed to solve the above problems and improve their environmental friendliness and application effects.

[0003] Bisphenol A (BPA) is a chemical substance widely used in the production of plastics and resins, mainly used for manufacturing polycarbonate plastics and epoxy resins. These materials are widely used in food packaging, beverage bottles, electronic products, medical devices, etc. in daily life. However, bisphenol A is difficult to degrade in the environment, and its potential biological toxicity has attracted wide public attention. Some studies have shown that BPA may interfere with the endocrine system in organisms, causing a series of health problems, including reproductive disorders, developmental abnormalities and other chronic diseases. Therefore, developing efficient catalytic degradation technologies to remove BPA in water bodies has important environmental protection and public health significance. Summary of the Invention

[0004] The present invention aims to provide a self-template synthesized linear biochar-based bimetallic material, a preparation method thereof and an application in degrading bisphenol A.

[0005] A preparation method of a self-template synthesized linear biochar-based bimetallic material comprises the following steps:

[0006] (1) Wash the ganoderma lucidum residue with ultrapure water three times, dry and crush it into a flocculent shape.

[0007] (2) Place the mashed Ganoderma lucidum in a tubular furnace and pyrolyze it in a nitrogen atmosphere to obtain biochar (BC).

[0008] (3) Mix biochar (BC), cobalt nitrate, and sodium molybdate in water, place them in a Teflon autoclave, and carry out a heating reaction to obtain CoMoO4 nanoparticles in-situ grown on biochar (BC).

[0009] (4) Wash the CoMoO4 nanoparticles in-situ grown on biochar (BC) with water and ethanol in sequence, and dry them naturally in an oven to obtain a linear biochar-based bimetallic material.

[0010] Preferably, the drying temperature in steps (1) and (4) is 60 - 80 °C, and the drying time is 12 - 72 h.

[0011] Preferably, in step (2), the nitrogen atmosphere is heated at a rate of 5 °C / min, the pyrolysis temperature is 300 - 600 °C, and the pyrolysis time is 1 - 2 h.

[0012] Preferably, in step (3), the atomic molar ratio of cobalt nitrate to sodium molybdate is 1:1 - 1:3.

[0013] Preferably, in step (3), the solid-liquid ratio of BC to water is (0.5 - 2) g:40 mL, and the mass ratio of BC:cobalt nitrate:sodium molybdate is (0.5 - 2):0.012:(0.010 - 0.029).

[0014] Preferably, in step (3), biochar (BC), cobalt nitrate, and sodium molybdate are mixed in a Teflon autoclave, and then the reaction kettle is placed in an oven for heating to prepare CoMoO4 nanoparticles.

[0015] Preferably, in step (3), the temperature of the heating reaction is 160 - 200 °C, and the time is 12 - 24 h; more preferably, the heating time is 12 h.

[0016] The expression of the self-template synthesized linear biochar-based bimetallic material described in the present invention is BC@CoMoO4.

[0017] The application of the self-template synthesized linear biochar-based bimetallic material obtained in the present invention in the degradation of bisphenol A, its technical solution, includes the following steps:

[0018] Prepare a BPA solution, adjust the pH of the BPA solution with sodium hydroxide and hydrochloric acid. After adding the BC@CoMoO4 catalyst, place it in a constant temperature shaker and oscillate to reach the adsorption-desorption equilibrium. After adding PMS, start the degradation reaction process. Extract 0.5 mL of the sample at each sampling time point, put it into a centrifuge tube containing 0.5 mL of methanol for quenching, and after filtering through a 0.22 μm filter membrane, measure the concentration of degraded BPA by high performance liquid chromatography (HPLC).

[0019] Preferably, the pH of the solution is 3 - 11, the dosage of the linear biochar-based bimetallic material BC@CoMoO4 is 0.1 g / L - 0.5 g / L, and the concentration of PMS is 0.2 mM - 0.6 mM; more preferably, the pH is 5.9, the dosage of BC@CoMoO4 is 0.4 g / L, and the concentration of PMS is 0.4 mM.

[0020] Preferably, the constant stirring rate of the constant temperature shaker is 160 - 200 rpm, and the reaction temperature is 25 ± 3 °C.

[0021] Preferably, in the high performance liquid chromatography (HPLC), 50% deionized water and 50% acetonitrile solution are used as the mobile phase, the flow rate is 1 mL / min, and the wavelength of the ultraviolet detector is 278 nm.

[0022] In the present invention, cobalt molybdenum bimetallic (CoMoO4) nanoparticles are grown in situ on the surface of biochar by a hydrothermal method to form a tight chemical bonding interface, avoiding the destruction of the heterojunction interface by high-temperature sintering, reducing the electron-hole separation efficiency, reducing defect sites and surface active sites, weakening the reaction activity, resulting in particle agglomeration and pore collapse, reducing the specific surface area and mass transfer efficiency, and at the same time may cause phase transformation or component separation, destroying the synergistic effect and affecting the catalytic performance.

[0023] Compared with the prior art, what are the advantages of the present invention?

[0024] (1) In the present invention, through the in-situ hydrothermal growth technique, cobalt molybdenum bimetallic (CoMoO4) nanoparticles are grown in situ on the surface of biochar with a micro-nano fibrous structure to form a tight chemical bonding interface. The coordination between the oxygen-containing functional groups on the BC surface and the metal precursor constructs a stable heterojunction structure, induces the lattice matching between CoMoO4 and BC, and gives full play to the synergistic effect between the metal and the micro-nano fibrous biochar, enabling it to have a high specific surface area, high porosity, and good electrochemical performance. The heterojunction interface forms an internal electric field through band bending, laying a foundation for excellent catalytic performance, enhancing the generation ability of sulfate radicals (SO4 - ·), thereby greatly improving the degradation rate of BPA. Defect sites can change the band structure of the heterojunction, induce electron accumulation or consumption at the heterojunction interface, and enhance the carrier separation efficiency.

[0025] (2) Through in-situ construction of heterojunction-defect synergy, the BC@CoMoO4 material is obtained after loading BC on CoMoO4 nanoparticles. Abundant defect sites such as pores and edge sites are formed on the surface of the BC@CoMoO4 material. These defects not only provide highly active nucleation sites for the anchoring of CoMoO4 nanoparticles, but also capture electrons or holes through dangling bonds, reducing interfacial charge recombination. The defect sites and the built-in electric field of the heterojunction act synergistically to further optimize the charge transport path, enabling the material to exhibit a multiple radical (SO4 - ·, ·OH, 1 O)) synergistic degradation mechanism, showing excellent catalytic performance, and remaining highly efficient in degrading in complex water quality environments with high concentrations of Cl - , HCO3 - etc., and having strong adaptability to complex pollutant environments.

[0026] (3) By exploring the influencing factors of the dosage of the catalyst, the concentration of PMS, and the pH of the reaction system on the degradation of BPA, the optimal degradation conditions are obtained: under the conditions of a catalyst dosage of 0.4 g / L, a concentration of potassium persulfate (PMS) of 0.5 mM, and a pH of 5.9, the degradation rate of BC@CoMoO4 for BPA can reach 98.18% within 5 minutes and complete degradation can be achieved within 7 minutes; compared with single BC, PMS, BC / PMS, and BC@CoMoO4, the degradation effect under the BC@CoMoO4 / PMS system is significantly improved, proving the synergistic catalytic mechanism of the heterojunction interface and defect sites, and verifying the unique advantage of the in-situ hydrothermal method in constructing heterojunctions, providing a reliable technical solution for the efficient degradation of BPA.

[0027] (4) Through the innovative design of the trinity of in-situ heterostructure construction-defect synergy-green process, this invention solves problems such as low efficiency, high cost, and poor environmental adaptability of traditional catalysts, providing an efficient and sustainable technical solution for the treatment of refractory organic pollutants in water bodies. Description of the Drawings

[0028] Figure 1 It is the XRD pattern of the BC@CoMoO4 composite material prepared in Example 1.

[0029] Figure 2 It is the SEM image of the biochar-based BC and the biochar-based cobalt-molybdenum bimetallic composite material prepared in Example 1. Figure (a) is the SEM image of the biochar-based BC prepared in Example 1, and Figure (b) is the SEM image of the biochar-based cobalt-molybdenum bimetallic composite material (BC@CoMoO4) prepared in Example 1.

[0030] Figure 3The effects of BC@CoMoO4 catalysts with different dosages on the degradation of BPA in Application Example 1.

[0031] Figure 4 The effects of different concentrations of PMS on the degradation of BPA by BC@CoMoO4 composite materials in Application Example 2.

[0032] Figure 5 The effects of different system pH values on the degradation of BPA by BC@CoMoO4 composite materials in Application Example 3.

[0033] Figure 6 The effects of BC@CoMoO4 composite materials with different cobalt / molybdenum molar ratios on the degradation of BPA in Application Example 4.

[0034] Figure 7 The effects of different anions and concentrations on the degradation of BPA by BC@CoMoO4 composite materials in Application Example 5. Figure (a) shows the effects of different anions at 10 mM on the degradation of BPA by BC@CoMoO4 composite materials, and Figure (b) shows the effects of different anions at 25 mM on the degradation of BPA by BC@CoMoO4 composite materials.

[0035] Figure 8 The effects of different humic acids on the degradation of BPA by BC@CoMoO4 composite materials in Application Example 6.

[0036] Figure 9 The effects of different quenchers on the degradation of BPA by BC@CoMoO4 composite materials in Application Example 7.

[0037] Figure 10 The effects of BC, PMS, BC / PMS, and BC@CoMoO4 on the degradation of BPA in Comparative Examples 1-4. Detailed implementation mode

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0039] Example 1

[0040] A preparation method of a self-template synthesized linear biochar-based bimetallic material, comprising the following steps:

[0041] (1) Wash the ganoderma lucidum residue with ultrapure water three times, dry it in an oven at 60 °C, and crush it into a flocculent state after 24 h.

[0042] (2) Place the crushed ganoderma lucidum residue in a tubular furnace, heat it to 600 °C at a heating rate of 5 °C / min in a nitrogen atmosphere, and pyrolyze for 2 h to obtain biochar (BC).

[0043] (3) Add 0.5 g of BC, 0.001 mol of Co(NO3)2·6H2O and 0.001 mol of Na2MoO4·2H2O into a Teflon high-pressure reactor. After adding 40 mL of ultrapure water, place it in an oven at 160 °C and heat for 12 h to prepare CoMoO4 nanoparticles in-situ grown on BC.

[0044] (4) Wash the in-situ grown CoMoO4 nanoparticles successively with ultrapure water and ethanol solution, and dry them in an oven at 80 °C for 12 h to obtain a linear biochar-based bimetallic material (BC@CoMoO4).

[0045] Perform XRD characterization analysis on the linear biochar-based bimetallic material (BC@CoMoO4) prepared in this example, as Figure 1 shown. The XRD pattern of BC shows that there is only one broad diffraction peak belonging to amorphous carbon. By comparing with CoMoO4 (PDF#97-028-1235), it can be seen that CoMoO4 is successfully loaded on the surface of BC. For BC@CoMoO4, the diffraction peaks at 19.04°, 24.68°, 30.66°, 36.32°, 41.38°, 54.14° and 58.82° respectively belong to the (100), (110), (111), (002), (121), (221) and (013) crystal planes of CoMoO4 (PDF#97-028-1235). The decrease of the characteristic peaks of BC@CoMoO4 biochar may be due to the low content of biochar.

[0046] Perform SEM characterization analysis on the biochar BC and the linear biochar-based bimetallic material (BC@CoMoO4) prepared in this example, as Figure 2 shown. As can be seen from Figure 2 (a), the original biochar BC has a highly uniform porous fibrous network structure with a smooth surface and no adhesion to other substances, which is beneficial to achieving a large specific surface area and constructing a layered pore structure; as can be seen from Figure 2 (b), many CoMoO4 nanoparticles on the surface of BC occupy it, which not only improves the dispersion between particles and forms more reaction sites, thus being more conducive to enhancing the catalytic activity of BC. The surface morphology of the biochar-based bimetallic material (BC@CoMoO4) formed after loading CoMoO4 nanoparticles becomes looser and rougher, forming more defect sites. The defect sites can change the energy band structure of the heterojunction, induce electron accumulation or consumption at the heterojunction interface, and enhance the carrier separation efficiency.

[0047] Example 2

[0048] A preparation method for self-template synthesis of a linear biochar-based bimetallic material, comprising the following steps:

[0049] (1) Wash the Ganoderma lucidum residue three times with ultrapure water, dry it in an oven at 60 °C, and crush it into a flocculent state after 16 h.

[0050] (2) Place the crushed Ganoderma lucidum residue in a tubular furnace, heat it to 400 °C at a heating rate of 5 °C / min in a nitrogen atmosphere and pyrolyze for 2 h to obtain biochar (BC).

[0051] (3) Add 1.5 g of BC, 0.001 mol of Co(NO3)6H2O and 0.002 mol of Na2MoO4·2H2O to a Teflon autoclave, add 40 mL of ultrapure water, and then place it in an oven at 180 °C and heat for 18 h to obtain in-situ grown CoMoO4 nanoparticles. 2· 6H2O and 0.002 mol of Na2MoO4·2H2O, add 40 mL of ultrapure water, and then place it in an oven at 180 °C and heat for 18 h to obtain in-situ grown CoMoO4 nanoparticles.

[0052] (4) Wash the in-situ grown CoMoO4 nanoparticles successively with ultrapure water and ethanol solution, and dry them in an oven at 70 °C for 36 h to obtain a linear biochar-based bimetallic material (BC@CoMoO4).

[0053] Example 3

[0054] A preparation method for synthesizing a linear biochar-based bimetallic material by self-template, comprising the following steps:

[0055] (1) Wash the Ganoderma lucidum three times with ultrapure water, dry it in an oven at 60 °C, and crush it into a flocculent state after 48 h.

[0056] (2) Place the crushed Ganoderma lucidum in a tubular furnace, heat it to 300 °C at a heating rate of 5 °C / min in a nitrogen atmosphere and pyrolyze for 2 h to obtain biochar (BC).

[0057] (3) Add 2.0 g of BC, 0.001 mol of Co(NO3)2·6H2O and 0.003 mol of Na2MoO4·2H2O to a Teflon autoclave, add 40 mL of ultrapure water, and then place it in an oven at 200 °C and heat for 22 h to obtain in-situ grown CoMoO4 nanoparticles.

[0058] (4) Wash the in-situ grown CoMoO4 nanoparticles successively with ultrapure water and ethanol solution, and dry them in an oven at 60 °C for 48 h to obtain a linear biochar-based bimetallic material (BC@CoMoO4).

[0059] Combined with XRD and SEM, the results show that the coordination between the oxygen-containing functional groups on the surface of BC and the metal precursor constructs a stable heterojunction structure, induces the lattice matching of CoMoO4 and BC, and gives full play to the synergistic effect of the metal and micro-nano fibrous biochar, endowing it with a high specific surface area, high porosity, and good electrochemical performance. The built-in electric field is formed by band bending at the heterojunction interface. These characteristics lay the foundation for its excellent catalytic performance, enhance the generation ability of sulfate radicals (SO4 - ·), and thus greatly improve the degradation rate of BPA. The XRD patterns of the linear biochar-based bimetallic materials prepared in Examples 2 and 3 are similar to those in Example 1, showing similar levels in terms of degradation effects. Considering energy conservation and environmental protection, the sintering temperature has less energy consumption and low environmental impact, so the materials fired at a lower temperature are selected for use.

[0060] Comparative Example

[0061] The difference between this comparative example and Example 1 is that a biochar-based bimetallic material is prepared by a high-temperature sintering method.

[0062] A preparation method of a biochar-based bimetallic material includes the following steps:

[0063] (1) Wash the ganoderma lucidum residue with ultrapure water three times, and dry and crush it into a flocculent shape in an oven at 60 °C.

[0064] (2) Place the crushed ganoderma lucidum residue in a tubular furnace, and heat it to 600 °C at a heating rate of 5 °C / min in a nitrogen atmosphere and pyrolyze for 2 h to obtain biochar (BC).

[0065] (3) Mix 2.0 g of the biochar (BC) prepared in step (2), 0.001 mol of Co(NO3)2·6H2O, and 0.001 mol of Na2MoO4·2H2O in a vacuum tubular high-temperature sintering furnace, and heat it to 400 - 600 °C at a rate of 5 °C / min in an N2 atmosphere and pyrolyze for 2 h to obtain a biochar-based bimetallic material.

[0066] The biochar-based bimetallic material prepared by the high-temperature sintering method is prone to reducing defect sites and surface active sites, weakening the reaction activity, resulting in particle agglomeration and pore collapse, reducing the specific surface area and mass transfer efficiency, possibly causing phase transformation or component separation in the composite material, destroying the synergistic effect, changing the surface chemical properties, and reducing functional groups, further affecting the catalytic performance. Therefore, the biochar-based bimetallic material prepared by the in-situ hydrothermal method in the present invention constructs a unique heterojunction, avoids the destruction of the heterojunction interface by high-temperature sintering, reduces the electron-hole separation efficiency, and has unique advantages.

[0067] To further prove the catalytic performance of the linear biochar-based bimetallic material (BC@CoMoO4) prepared by the present invention and its degradation mechanism of BPA in sewage, the present invention studied the effects of the dosage of the BC@CoMoO4 catalyst, the concentration of PMS, the pH of the reaction system, the cobalt-molybdenum ratio of the BC@CoMoO4 catalyst, different anions and their concentrations (such as Cl - , SO4 2 -, NO3 - , HCO3 - , etc.), the dosage of humic acid (HA), and the effects of different dosages of quenchers (methanol, tert-butanol, p-benzoquinone, histidine).

[0068] Application Example 1

[0069] The effects of different dosages of the BC@CoMoO4 catalyst on the degradation of BPA include the following steps:

[0070] Prepare 5 portions of 40 mL of 15 mg / L BPA solution in conical flasks, adjust the pH of the BPA solution to 5.9 with sodium hydroxide and hydrochloric acid. At room temperature of 25 ± 3 °C, place the conical flasks on a constant temperature shaker at a constant stirring rate of 180 rpm, and add 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, and 0.5 g / L of the BC@CoMoO4 catalyst respectively. Oscillate and react in the shaker for 30 min to reach adsorption-desorption equilibrium. Add 0.5 mM PMS to initiate the degradation reaction process. Extract 0.5 mL of the sample at each sampling time point and put it into a centrifuge tube containing 0.5 mL of methanol for quenching. After filtering through a 0.22 μm filter membrane, measure the concentration of BPA after degradation by high performance liquid chromatography (HPLC). The mobile phase of HPLC is 50% deionized water and 50% acetonitrile solution, the flow rate is 1 mL / min, and the wavelength of the ultraviolet detector is 278 nm. The results of the BPA degradation rate are as Figure 3 shown.

[0071] According to Figure 3As shown, after 9 min of degradation reaction, the degradation rates of BPA by BC@CoMoO4 catalysts at 0.1 g / L and 0.2 g / L were 87.86% and 97.86% respectively; the degradation rates of 0.3 g / L BC@CoMoO4 at 7 min and 10 min of oscillation reaction were 98.68% and 100% respectively; the degradation rates of 0.4 g / L BC@CoMoO4 at 5 min and 7 min of oscillation reaction were 98.18% and 100% respectively; the degradation rates of 0.5 g / L BC@CoMoO4 at 5 min and 7 min of oscillation reaction were 98.46% and 100% respectively; as the dosage of BC@CoMoO4 increased, the degradation rate of BPA by BC@CoMoO4 increased. Considering the preparation cost of the catalyst comprehensively; more preferably, the dosage of BC@CoMoO4 was selected to be 0.4 g / L.

[0072] Application Example 2

[0073] The effects of different concentrations of PMS on the degradation of BPA by BC@CoMoO4 include the following steps:

[0074] Prepare 5 portions of 40 mL of 15 mg / L BPA solution in conical flasks, adjust the pH of the BPA solution to 5.9 with sodium hydroxide and hydrochloric acid. At room temperature (25 ± 3 °C), place the conical flasks on a constant temperature shaker at a constant stirring rate of 180 rpm, add 0.4 g / L of BC@CoMoO4 catalyst to each, and oscillate in the shaker for 30 min to reach adsorption-desorption equilibrium. Then, add 0.2 mM, 0.3 mM, 0.4 mM, 0.5 mM, and 0.6 mM of PMS respectively to start the degradation reaction process. Extract 0.5 mL of the sample at each sampling time point, put it into a centrifuge tube containing 0.5 mL of methanol for quenching, and after filtering through a 0.22 μm filter membrane, measure the concentration of BPA after degradation by high performance liquid chromatography (HPLC). The measurement conditions are the same as those in Application Example 1. The results of the BPA degradation rate are as Figure 4 shown.

[0075] According to Figure 4As shown, after 9 minutes of the degradation reaction, the degradation rates of BPA by 0.2 mM, 0.3 mM, 0.4 mM, and 0.5 mM of PMS on the BC@CoMoO4 catalyst were 70.88%, 87%, 95.71%, respectively; the degradation rates of BPA by 0.5 mM of PMS on the BC@CoMoO4 catalyst at 7 minutes and 10 minutes were 98.18% and 100%, respectively; the degradation rates of BPA by 0.6 mM of PMS on the BC@CoMoO4 catalyst at 7 minutes and 10 minutes were 97.99% and 100%, respectively; with the increase in the concentration of PMS, the degradation rate of BPA by BC@CoMoO4 increased, but after the PMS concentration reached 0.5 mM, the degradation rate of BPA by BC@CoMoO4 began to decrease.

[0076] Application Example 3

[0077] The influence of different pH values on the degradation of BPA by BC@CoMoO4 includes the following steps:

[0078] On the basis of the reaction conditions obtained from Application Examples 1 - 2, 5 portions of 40 mL of 15 mg / L BPA solution were prepared and placed in conical flasks. The pH values of the BPA solutions were adjusted to 3, 5.9, 7, 9, and 11 with sodium hydroxide and hydrochloric acid, respectively. At room temperature (25 ± 3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm through a thermostatic shaker. 0.4 g / L of the BC@CoMoO4 catalyst was added to each flask, and the reaction was oscillated in the shaker for 30 minutes to reach the adsorption - desorption equilibrium. Then, 0.5 mM of PMS was added to each flask to initiate the degradation reaction process. 0.5 mL of the sample was extracted at each sampling time point and placed in a centrifuge tube containing 0.5 mL of methanol for quenching. After filtration through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high - performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The results of the BPA degradation rate are as Figure 5 shown.

[0079] According to Figure 5As shown, at pH 3, the degradation rates of 0.5 mM PMS on the degradation of BPA by the BC@CoMoO4 catalyst were 97.10% and 100% at 5 min and 7 min of the degradation reaction, respectively; at pH 5.9, the degradation rates of 0.5 mM PMS on the degradation of BPA by the BC@CoMoO4 catalyst were 98.19% and 100% at 5 min and 7 min of the degradation reaction, respectively; at pH 7, the degradation rates of 0.5 mM PMS on the degradation of BPA by the BC@CoMoO4 catalyst were 91.80% and 100% at 3 min and 5 min of the degradation reaction, respectively; at pH 11, the degradation rates of 0.5 mM PMS on the degradation of BPA by the BC@CoMoO4 catalyst were 95.48% and 100% at 3 min and 5 min of the degradation reaction, respectively; the degradation rate of BC@CoMoO4 on BPA increased with the increase of pH value.

[0080] Application Example 4

[0081] The degradation of BPA by BC@CoMoO4 composites with different cobalt-molybdenum ratios includes the following steps:

[0082] On the basis of obtaining the reaction conditions by using Application Examples 1-3, 3 portions of 40 mL of 15 mg / L BPA solution were prepared and placed in conical flasks. At room temperature (25 ± 3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm by a thermostatic shaker. 0.4 g / L of BC@CoMoO4 catalysts with Co:Mo = 1:1, Co:Mo = 1:2, and Co:Mo = 1:3 were added respectively. After oscillating and reacting in the shaker for 30 min to reach the adsorption-desorption equilibrium, 0.5 mM of PMS was added to each to initiate the degradation reaction process. 0.5 mL of the sample was extracted at each sampling time point and put into a centrifuge tube containing 0.5 mL of methanol for quenching. After filtering through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The results of the BPA degradation rate are as Figure 6 shown.

[0083] According to Figure 6It can be seen that when the molar ratio of Co:Mo = 1:1, the degradation rates of BPA by the BC@CoMoO4 catalyst at 3 min and 5 min of the degradation reaction are 98.18% and 100% respectively; when the molar ratio of Co:Mo = 1:2, the degradation rates of BPA by the BC@CoMoO4 catalyst at 3 min and 5 min of the degradation reaction are 96.58% and 100% respectively; when the molar ratio of Co:Mo = 1:3, the degradation rate of BPA by the BC@CoMoO4 catalyst at 9 min of the degradation reaction is 96.19%. As the proportion of molybdenum in the cobalt-molybdenum ratio increases, the degradation rate of BPA by BC@CoMoO4 decreases. More preferably, the molar ratio of Co:Mo = 1:1 is selected.

[0084] Application Example 5

[0085] The influence of different anion concentrations on the degradation of BPA by BC@CoMoO4 includes the following steps:

[0086] On the basis of the reaction conditions obtained from Application Examples 1-4, 10 portions of 40 mL of 15 mg / L BPA solution were prepared and placed in conical flasks. At room temperature (25 ± 3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm by a thermostatic shaker. 0.4 g / L of the BC@CoMoO4 catalyst with a cobalt-molybdenum ratio of 1:1 was added to each. The reaction was oscillated in the shaker for 30 min to reach adsorption-desorption equilibrium. 10 mM Cl - 、10 mM SO4 2- 、10 mM NO3 - 、10 mM HCO3 - ,25 mM Cl - 、25 mM SO4 2- 、25 mM NO3 - 、25 mM HCO3 - and 0.5 mM PMS were added, and then the degradation reaction process was started. 0.5 mL of the sample was extracted at each sampling time point and placed in a centrifuge tube containing 0.5 mL of methanol for quenching. After filtration through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The degradation rate of BPA is as Figure 7 shown.

[0087] According to Figure 7 (a) shown, it can be seen that in the experimental group with the addition of 10 mM Cl - , the degradation rates of BPA at 5 min and 7 min of degradation are 99.08% and 100% respectively; when 10 mM of SO4 2- 、10 mM of NO3 - were added, the degradation rates of BPA at 9 min of degradation were 95.13% and 93.31% respectively; when 10 mM of HCO3- , after 2 min and 3 min of degradation, the degradation rates of BPA were 98.34% and 100% respectively; according to Figure 7 (b), it can be seen that in the experimental group with 25 mM Cl - , the degradation rates of BPA were 98.58% and 100% respectively after 5 min and 7 min of degradation; in the experiment with 25 mM of SO4 2- and 25 mM of NO3 - , after 9 min of degradation, the degradation rates of BPA were 95.31% and 91.88% respectively; in the experiment with 25 mM of HCO3 - , after 2 min and 3 min of degradation, the degradation rates of BPA were 98.18% and 100% respectively; in the blank experiment, after 5 min and 7 min of degradation, the degradation rates of BPA were 98.19% and 100% respectively. Analysis shows that SO4 2- and NO3 - have an inhibitory effect on the degradation of BPA, while for Cl - , different concentrations show different effects. 10 mM Cl - has a weak promoting effect on the degradation of BPA, 25 mM Cl - has an inhibitory effect on the degradation of BPA, while HCO3 - has a strong promoting effect on the degradation of BPA.

[0088] Application Example 6

[0089] The effects of different dosages of humic acid (HA) on the degradation of BPA by BC@CoMoO4 include the following steps:

[0090] On the basis of the reaction conditions obtained from Application Examples 1 - 4, 3 portions of 40 mL of 15 mg / L BPA solution were prepared and placed in conical flasks. Without adding humic acid as the blank experiment, 10 mg and 20 mg of humic acid were added to the other two BPA solutions respectively. At room temperature (25 ± 3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm through a thermostatic shaker. 0.4 g / L of BC@CoMoO4 catalyst with a cobalt - molybdenum ratio of 1:1 was added to each. The reaction was oscillated in the shaker for 30 min to reach the adsorption - desorption equilibrium. After adding 0.5 mM of PMS, the degradation reaction process was started. 0.5 mL of the sample was extracted at each sampling time point and placed in a centrifuge tube containing 0.5 mL of methanol for quenching. After filtration through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high - performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The results of the BPA degradation rate are as Figure 8 shown.

[0091] According to Figure 8As shown, in the blank experiment, the degradation rates of BPA were 98.18% and 100% after 5 min and 7 min of degradation, respectively. After adding 10 mg and 20 mg of humic acid, the degradation rates of BPA by BC@CoMoO4 were 91.14% and 81.01% after 9 min of degradation, respectively. When the addition amount of humic acid increased, the degradation rate of BPA by BC@CoMoO4 showed a decrease, indicating that the addition of humic acid did not promote the degradation of BPA by BC@CoMoO4.

[0092] Application Example 7

[0093] The influence of different quenchers on the degradation of BPA by BC@CoMoO4 includes the following steps:

[0094] On the basis of the reaction conditions obtained from Application Examples 1-4, 5 portions of 40 mL of 15 mg / L BPA solution were prepared and placed in conical flasks. The blank experiment was without adding any quencher. 100 mM of methanol, 100 mM of tert-butanol, 20 mM of p-benzoquinone, and 1 mM of histidine were added to the other 4 portions of BPA solution, respectively. At room temperature (25 ± 3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm through a thermostatic shaker. 0.4 g / L of BC@CoMoO4 catalyst with a cobalt-molybdenum ratio of 1:1 was added to each. The reaction was oscillated in the shaker for 30 min to reach adsorption-desorption equilibrium. After adding 0.5 mM of PMS, the degradation reaction process was started. 0.5 mL of the sample was extracted at each sampling time point and quenched in a centrifuge tube containing 0.5 mL of methanol. After filtration through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The results of the BPA degradation rate are as Figure 9 shown.

[0095] From Figure 9 as shown, when the quenchers added were 100 mM of methanol, 1 mM of histidine, 100 mM of tert-butanol, and 20 mM of p-benzoquinone, the degradation rates after 9 min of degradation were 53.24%, 67.38%, 92.46%, and 99.21%, respectively; in the blank experiment, the degradation rates of BPA were 98.19% and 100% at 5 min and 7 min of degradation, respectively.

[0096] According to the analysis results of the degradation rate, the quenchers of methanol, histidine, and tert-butanol had an inhibitory effect on the degradation of BPA. Among them, the inhibitory effect of methanol was the most obvious, the inhibitory effect of histidine was the second, and the inhibitory effect of tert-butanol was weaker. Since methanol, histidine, and tert-butanol were quenchers of sulfate radical (SO4 - ·), hydroxyl radical (·OH), and non-radical singlet oxygen ( 1 O2), respectively, it indicated that SO4 - ·, ·OH, and1 O2 was involved in the degradation of BPA, among which the contribution of SO4 - · was greater; p-benzoquinone was used to quench superoxide radicals (·O2 - ), as Figure 9 shown, the inhibitory effect of p-benzoquinone on the degradation of BPA was not significant, indicating that the quenching of superoxide radicals (·O2 - ) had limited contribution in this experimental system.

[0097] The biochar bimetallic material BC@CoMoO4 prepared in Examples 1-3 was applied to the degradation of the organic pollutant bisphenol A. By exploring the influencing factors of the BC@CoMoO4 catalyst for the degradation of BPA in Application Examples 1-4, according to the data results of the degradation rate, the optimal reaction conditions of the BC@CoMoO4 material in the degradation of bisphenol A (BPA) were determined as follows: the dosage of the BC@CoMoO4 catalyst was 0.4 g / L, the concentration of potassium persulfate (PMS) was 0.5 mM, and the pH value was 5.9; meanwhile, in Application Examples 5-7, on the basis of the optimal reaction conditions, the degradation ability of the BC@CoMoO4 catalyst in a complex water quality environment was investigated.

[0098] Control group

[0099] Four control experimental groups were set up to investigate the results of the degradation of BPA by biochar BC, PMS, BC+PMS, and BC@CoMoO4 respectively, including the following specific steps:

[0100] Four 40 mL of 15 mg / L BPA solutions with a pH of 5.9 were prepared and placed in conical flasks. At room temperature (25±3 °C), the conical flasks were stirred at a constant stirring rate of 180 rpm by a thermostatic shaker. 0.4 g / L biochar (BC), 0.5 mM PMS, 0.4 g / L BC activator and 0.5 mM PMS, and 0.4 g / L BC@CoMoO4 were added respectively for the degradation reaction. The reaction was oscillated in the shaker for 30 min to reach the adsorption-desorption equilibrium. 0.5 mL of the sample was extracted at each sampling time point and placed in a centrifuge tube containing 0.5 mL of methanol for quenching. After filtration through a 0.22 μm filter membrane, the concentration of BPA after degradation was measured by high performance liquid chromatography (HPLC). The measurement conditions were the same as those in Application Example 1. The degradation rate results were as Figure 10 shown.

[0101] As Figure 10As shown, in the control group, when only BC, PMS, BC / PMS, and BC@CoMoO4 were used, the degradation rates of BPA were 11.04%, 12.47%, 13.94%, and 13.72% respectively when the degradation reaction reached 9 minutes. During the degradation process of BPA by BC@CoMoO4 / PMS, the degradation rate of BPA was 98.19% when the degradation reaction reached 5 minutes, and the degradation rate of BPA was 100% when the degradation reaction reached 7 minutes.

[0102] In addition, it can be seen from the comparison with the control group in Application Examples 1-7 that in the degradation systems using only biochar BC, PMS, BC+PMS, and BC@CoMoO4, the degradation rate of BPA decreased significantly compared with that in the BC@CoMoO4 / PMS system, the degradation effect was significantly improved, which proved the synergistic catalytic mechanism of the heterojunction interface and defect sites in the linear biochar-based bimetallic material BC@CoMoO4. The reason may be that cobalt molybdate (CoMoO4) nanoparticles grew directionally on the surface of biochar, forming a tight chemical bonding interface (Co-O-C / Mo-O-C bond). This may be due to the coordination between the oxygen-containing functional groups on the surface of in-situ grown biochar and the metal precursor, constructing a stable heterojunction structure and inducing the lattice matching between CoMoO4 and BC.

[0103] The above has described in detail the preferred specific embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any person skilled in the art within the scope of knowledge can also make various changes or equivalent substitutions without departing from the purpose of the present invention. These changes or equivalent substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a self-template synthesized linear biochar-based bimetallic material, characterized in that, It includes the following steps: (1) Wash, dry and then crush the Ganoderma lucidum residue into a flocculent state; (2) Pyrolyze the crushed Ganoderma lucidum residue in a nitrogen atmosphere to obtain biochar; (3) Mix the biochar obtained in step (1), cobalt nitrate and sodium molybdate in water, place it in a Teflon autoclave for heating reaction, and then wash and dry to obtain a self-template synthesized linear biochar-based bimetallic material.

2. The preparation method of the self-template synthesized linear biochar-based bimetallic material according to claim 1, characterized in that, In steps (1) and (4), the drying temperature is 60 - 80 °C, and the drying time is 12 - 72 h.

3. The preparation method of the self-template synthesized linear biochar-based bimetallic material according to claim 1, characterized in that In step (2), the nitrogen atmosphere is heated at a rate of 5 °C / min, the pyrolysis temperature is 300 - 600 °C, and the pyrolysis time is 1 - 2 h.

4. The preparation method of the self-template synthesized linear biochar-based bimetallic material according to claim 1, characterized in that, In step (3), the molar ratio of cobalt nitrate to sodium molybdate is 1:(1 - 3); the solid-liquid ratio of BC to water is (0.5 - 2) g:40 mL; the mass ratio of BC:cobalt nitrate:sodium molybdate is (0.5 - 2): 0.012：(0.010-0.029)。 5. The preparation method of the self-template synthesized linear biochar-based bimetallic material according to claim 1, characterized in that, In step (3), the temperature of the heating reaction is 160 - 200 °C, and the heating time is 12 - 24 h.

6. The linear biochar-based bimetallic material prepared by the method according to any one of claims 1 - 5.

7. The application of the linear biochar-based bimetallic material according to claim 6 in activating PMS to degrade bisphenol A.

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