CN111111637A

CN111111637A - Boron-doped non-metallic catalyst and preparation method and application thereof

Info

Publication number: CN111111637A
Application number: CN201911413310.5A
Authority: CN
Inventors: 李兴发; 梁丹丹
Original assignee: Taiyuan University of Technology
Current assignee: Taiyuan University of Technology
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2020-05-08

Abstract

The invention discloses a boron-doped non-metallic catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: adding a carbon material into an acid solution, heating, soaking, filtering, washing with ultrapure water, and drying; dispersing the boron-containing precursor into a volatile solvent, adding the boron-containing precursor, heating in an oil bath, washing with ultrapure water after the reaction is finished, and drying; and then roasting the mixture in a non-oxidizing atmosphere to obtain the boron-doped non-metallic catalyst. The invention replaces the high-toxicity heavy metal catalyst with the low-toxicity boron-doped non-metal catalyst, has the characteristic of environmental protection, has good degradation and removal effects on organic pollutants, and shows extremely high catalytic activity and wide application range of the catalyst.

Description

Boron-doped non-metallic catalyst and preparation method and application thereof

Technical Field

The invention relates to the technical field of catalyst materials, in particular to a boron-doped non-metal catalyst and a preparation method and application thereof.

Background

In recent decades, with the rapid development of industry and the improvement of living standard of people, many new chemicals continuously enter the environment, and the pollutants have the characteristics of low concentration, high toxicity, difficult biodegradation and the likeIt is difficult to remove by conventional treatment techniques, which may have serious impact on the ecological environment. The advanced oxidation technology based on sulfate radical is to generate strong oxidizing sulfate radical (SO) after persulfate is used for activation₄ ^●−) The water treatment technology for degrading organic pollutants has the advantages of environmental friendliness, simple equipment, quick reaction and the like, and has great application potential in the aspects of water treatment, soil remediation, sludge treatment and landfill leachate treatment. Among all persulfate activation methods, transition metal activation is favored because of its advantages such as simple equipment, easy operation, and low cost. However, the activation with noble metals is costly and not practical for large-scale treatment of wastewater, and the metal ions dissolved out during use of heavy metal catalysts are likely to cause secondary pollution. In the case of cobalt, excessive amounts of cobalt can lead to asthma, pneumonia and myocardial infarction, and may be carcinogenic. In addition to heavy metal contamination, metal leaching may also result in severe loss of catalytic effect, reduced recycling performance, and the production of large amounts of sludge. Therefore, the exploration of the green activated persulfate technology which is environment-friendly and has excellent effect has important scientific significance and application value.

Disclosure of Invention

The invention aims at the technical problems and provides a preparation method of a boron-doped non-metal catalyst, the boron-doped non-metal catalyst prepared by the method has high activity in the range of pH = 3-11, has high degradation efficiency on organic pollutants, has wide application range and simple use steps; meanwhile, the preparation method is simple and easy to operate, low in process cost and wide in application range, and industrial production can be realized.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a boron-doped non-metallic catalyst comprises the following steps: adding a carbon material into an acid solution, heating and soaking for 0.5-24h at the temperature of 25-200 ℃, further preferably at the temperature of 100 ℃, heating for 4h, wherein the weight ratio of the carbon material to the acid solution is 1:1-1:500, further preferably 1:100, filtering, washing with ultrapure water, and drying to obtain an intermediate 1; dispersing the intermediate 1 into a volatile solvent, adding a boron-containing precursor, heating in an oil bath, washing with ultrapure water after the reaction is finished, and drying to obtain an intermediate 2; and roasting the intermediate 2 at the temperature of 300-900 ℃ for 0.5-6h in a non-oxidizing atmosphere to obtain the boron-doped non-metal catalyst, wherein the further preferable temperature is 800 ℃ and the roasting time is 1 h.

Further, the main components of the carbon material are graphene and carbon nanotubes, the graphene is high-purity graphene, graphene oxide or reductive graphene oxide, and the carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes or multi-walled carbon nanotubes, and are preferably multi-walled carbon nanotubes.

Furthermore, the diameter of the multi-wall carbon nano tube is 2-50 nm, and is preferably 8-20 nm.

Further, the volatile solvent is methanol, ethanol, water, acetonitrile, isopropanol or cyclohexane, preferably ethanol.

Further, the boron-containing precursor is boric acid, borate or a boron-substituted organic substance containing any number of boron atoms, and boric acid and 1, 4-phenyl diboronic acid are preferred.

Further, the non-oxidizing atmosphere is a non-oxidizing gas such as nitrogen, hydrogen, helium, or argon, and preferably nitrogen.

Further, the acid solution is nitric acid, sulfuric acid, hydrochloric acid or phosphoric acid, preferably nitric acid.

The invention also provides a boron-doped non-metallic catalyst prepared by the preparation method of any one of the technical schemes.

The invention also provides an application method for catalytically degrading organic pollutants in wastewater by using the boron-doped non-metallic catalyst.

Further, the wastewater is organic wastewater, the initial pH value is 3-11, preferably the pH value is 5-9, an oxidant and a catalyst are added in the treatment process, the operation is very simple, the concentration of organic pollutants in the wastewater is 1-100 mg/L, preferably the concentration is 5-20 mg/L, the boron-doped non-metal catalyst is used in the application process in an amount of 0.05-2 g/L, preferably 0.1-0.5 g/L, the oxidant is peroxymonosulfate or peroxydisulfate, preferably peroxymonosulfate, the mass concentration of the peroxymonosulfate is 0.1-10 g/L, preferably 1-2 g/L, and the degradation time of the wastewater is 0.1-24 h, preferably 0.5-2 h. The boron-doped non-metallic catalyst prepared by the invention has extremely high catalytic removal effect on phenol pollutants, and the removal rate can reach more than 95% within 1h under the condition that the initial pH = 7.

In the present invention, the carbon nanotube has intact sp²A carbon surface, each carbon atom forming an sp with three adjacent carbon atoms²The hybridized covalent bond has good conductivity and excellent catalytic potential because the outermost layer of the carbon atom has four valence electrons, and each carbon atom has one non-bonded electron which forms a ring-shaped large pi bond in the six-membered ring grid structure of the carbon nanotube.

Research shows that holes and defects generated by the modified carbon nanotubes can more effectively activate oxygen-oxygen bonds on persulfate than original carbon surfaces, and have larger adsorption energy and electron transfer capacity. The doping modification of the carbon network can change the surface structure of the carbon nano tube, so that a large number of steps, holes and defects are generated on the surface of the carbon nano tube. Carbon materials are catalytically active by activating persulfate with electron-rich carbon backbones, diverse functional groups and defect sites, and thus doping of heteroatoms may lead to carbon backbone distortion and electron density rearrangement, thereby creating more active sites.

The boron atom electron layer structure is 1s²2s²2p_x ¹Capable of forming sp similar to graphene and carbon nanotubes²The hybrid electron orbit is favorable for generating active species by the action of the structure and O-O bonds on persulfate. And after boron doping, the original sp on the carbon nano-tube²The network structure of the hybrid carbon is not obviously changed, and the high-speed transmission of electrons is not influenced; secondly, the electronegativity of the boron atom is lower than that of the carbon atom, so that covalent electrons formed by the carbon and the boron after doping are slightly polarized to the carbon, the boron atom is enabled to carry partial positive charges, and a new catalytic center is easily formed at the position of the boron atom. Thus, boron-doped carbon nanotubesThe pipe catalyst has certain innovativeness and application potential when being used for degrading organic matters by using metal-free activated persulfate.

Compared with the prior art, the invention has the beneficial effects that: the carbon material is used for replacing noble metal and heavy metal catalysts, so that the cost of wastewater treatment is reduced, and secondary pollution to the environment is reduced; the preparation method is simple and easy for industrial production; the method can be used for other carbon materials and has wide application range; the reaction system can react at room temperature, the device is simple, the cost is low, the environment is friendly, and the method has an industrial application prospect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a scanning electron microscope and a transmission electron microscope image of the boron-doped non-metallic catalyst prepared in example 1;

FIG. 2 is an X-ray photoelectron spectrum of carbon and boron of the boron-doped non-metallic catalyst prepared in example 1;

FIG. 3 is a Raman spectrum of the boron-doped non-metallic catalyst prepared in example 1;

FIG. 4 is a graph illustrating the degradation of phenol by the boron doped non-metallic catalyst and the reference material prepared in example 1;

FIG. 5 is a graph showing the inhibition effect on phenol degradation when different chemical trapping agents are added;

FIG. 6 shows the active species generated by electron paramagnetic resonance measurement upon catalytic degradation;

FIG. 7 shows the degradation results of phenol in the boron-doped non-metallic catalyst prepared in example 1 and in comparative example 1;

FIG. 8 is a graph of total organic carbon removal for phenol versus boron doped non-metallic catalyst prepared in example 1 and comparative example 1;

FIG. 9 is a graph of the effect of carbon material structure on catalyst activity;

FIG. 10 is a graph of the effect of doping a precursor on catalyst activity;

FIG. 11 is a graph of the effect of the calcination atmosphere on catalyst activity;

FIG. 12 is a graph of the effect of calcination temperature on catalyst activity;

FIG. 13 is a graph of the effect of an oxidizing agent on the effectiveness of catalytic degradation;

FIG. 14 is a graph showing the effect of contaminants on the catalytic degradation effect.

Detailed Description

The following describes embodiments of the present invention in further detail through a description of examples. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Preparation of a boron-doped non-metallic catalyst:

adding 1.0 g of carbon nanotube into 100 mL of nitric acid solution according to data in Table 1, carrying out heating reflux reaction for 4h at 80 ℃ in an oil bath, repeatedly washing the mixture to be neutral by using ultrapure water after filtering to obtain an intermediate 1, dispersing the intermediate 1 into 50 mL of absolute ethyl alcohol, adding 1.0 g of boron-containing precursor, carrying out heating stirring reaction for 4h at 80 ℃ in an oil bath, filtering the mixture after the reaction is finished, repeatedly washing the mixture to be neutral by using ultrapure water, drying the obtained solid in an oven at 120 ℃, and then roasting the solid in a tubular furnace under a certain atmosphere to obtain the boron-doped nonmetal catalyst.

TABLE 1 preparation of boron-doped non-metallic catalysts test parameters

Characterization of boron-doped non-metallic catalysts:

(1) surface morphology of boron-doped non-metallic catalyst

The carbon nanotube is a hollow tubular carbon nanomaterial crystallized from graphite carbon atoms, the macroscopic morphology of the carbon nanotube is black powder, and the microstructure of the carbon nanotube can be observed by a high-power electron microscope. As is apparent from the Scanning Electron Microscope (SEM) photograph and the Transmission Electron Microscope (TEM) photograph of fig. 1, the boron-doped carbon nanotube prepared in example 1 has a slender tubular structure, and particularly, the boron-doped carbon nanotube has a hollow structure, which is advantageous for the mass transfer process of the contaminants and the oxidant in the liquid-phase catalytic reaction, and accelerates the reaction.

(2) Chemical composition of boron-doped non-metallic catalyst

The catalyst was boron-doped carbon nanotubes, and the chemical composition of the catalyst prepared in example 1 was identified by X-ray photoelectron spectroscopy (XPS) in order to confirm the doping of boron and the chemical morphology after doping. The XPS full spectrum analysis finds that boron element is detected besides carbon element of the carbon nano tube, and proves the successful doping of boron. By further fitting and analyzing the fine spectra of carbon and boron, the fitting results are shown in fig. 2. As can be seen from the C1 s spectrum of FIG. 2a, the main peak at 284.0eV is attributed to the carbon-carbon bond (C-C) of the carbon nanotube itself, and the satellite peak at 290.5 eV is attributed to pi-pi, indicating that after the boron is doped into the original carbon ring, although part of the carbon atoms are replaced to form new bonds, the sp of the carbon ring as a whole is replaced to form new bonds²The bonding characteristics are not destroyed. And the B1 s spectrum of fig. 2B shows that the doped boron forms boron-oxygen bonds (B-O) in which part of boron is oxidized in addition to boron-carbon bonds (B-C).

Because the boron-doped carbon nano tube belongs to a non-metal catalyst, the catalyst has the characteristics that no metal catalytic active center exists, and catalytic active sites are positioned at defect structures. After doping, boron atoms enter the carbon ring to form boron-carbon bonds with carbon atoms, and because the size of the boron atoms is close to that of the carbon atoms, the whole structure of the carbon ring is not influenced by the doping of a small amount of boron, but because the electronegativity (2.05) of boron is smaller than that (2.55) of carbon, the electron density around the boron atoms is biased to the carbon atoms, so that the doped boron atoms are formedAnd the carbon atom adjacent to boron changes its electron density compared with the carbon atom on the carbon ring before doping, thereby forming a defect site, which becomes a catalytic reaction center. The boron-doped carbon nanotubes prepared in example 1 were characterized by Raman spectroscopy (FIG. 3) and found to be 1340 cm in length^-1D peak (representing disordered and defective structure) and 1579 cm^-1The G peak (representing a regular graphite structure) is changed compared with the G peak before doping, wherein the G peak is obviously reduced, and the ID/IG is also increased from 1.05 before doping to 1.23 after doping, which shows that the doping causes the increase of the surface defects of the carbon nano tube.

Due to the specificity of the non-metallic catalyst active center, i.e. the active sites are located at steps, corners, edges, defects, etc., this is completely different from the role played by the complete surface structure and chemical bonds. The active center of the catalyst prepared by the invention is positioned at the place where the electron density of carbon and boron is unbalanced, and other defect structures such as steps, holes and the like are formed due to doping, which is different from a carbon ring structure of a carbon nano tube and boron carbide and boron oxide structures formed by boron, carbon and oxygen respectively, and the degradation of phenol by using the catalyst and various boron-containing substances is compared through the embodiment 1. As can be seen from fig. 4, none of boric acid, boron oxide, boron carbide, amorphous boron, crystalline boron, etc., which is a precursor of boron used for doping, shows a remarkable catalytic activity, and it is confirmed that not simple boron-oxygen bond (B-O), boron-carbon bond (B-C), and boron-boron bond (B-B) can catalyze degradation reaction, but defect structure formed by boron doping has a catalytic function.

(3) Mechanism of catalytic degradation

In general, there is a free radical mechanism in the metal catalyzed persulfate reaction, i.e., the oxidant forms highly reactive hydroxyl radicals (. OH) and sulfate radicals (. SO) after activation by the catalyst₄ ^●−) And (4) degrading pollutants. In the non-metal catalytic reaction, there is a non-free radical mechanism, i.e. active center formed by defect site activates oxidant to form singlet oxygen: (¹O₂) And (4) degrading pollutants. These active substances can react with different chemical capture agents, therebyThe concentration in the reaction system is reduced, and the degradation efficiency of the pollutants is reduced. As can be seen from fig. 5, when the catalyst prepared in example 1 was added with methanol, a radical inhibitor, in a reaction system for degrading phenol, the degradation efficiency of phenol was linearly decreased, indicating that hydroxyl radicals and sulfate radicals were present in the system. Furthermore, the experiment of using p-benzoquinone to replace methanol shows that the degradation efficiency of phenol is reduced, and the reduction trend is close to the result of adding methanol, which indicates that superoxide anion free radical (O) exists in the system₂ ^−•) This radical is generally believed to result from the chain reaction of hydroxyl radicals. After the L-histidine is used as an inhibitor, the degradation of phenol is also inhibited, but the inhibition degree is lower than that of methanol and p-benzoquinone, and the singlet oxygen exists in the reaction system. In combination with the above results, not only hydroxyl radicals, sulfate radicals, superoxide anion radicals, but also singlet oxygen are present in the catalytic reaction.

To confirm the above judgment, we detected the active species in the reaction by Electron Paramagnetic Resonance (EPR). The instrumental measurement method uses DMPO (5, 5-dimethyl-1-pyrrole N-oxide) as a spin trapping agent to detect free radical active substances, and uses TMP (2, 2,6, 6-tetramethyl-4-piperidinol) as another spin trapping agent to detect singlet oxygen. Since different active substances have a spectrum with a specific shape, the active species in the system can be effectively identified. As can be seen from fig. 6, not only are significant hydroxyl and sulfate radicals present in the reaction system (fig. 6 a) and a small amount of superoxide anion radicals (fig. 6 b), but a large amount of singlet oxygen is also detected (fig. 6 c). The results of the instrumental characterization confirmed the results of the chemical inhibition reactions, indicating the presence of a variety of active species in the catalytic reaction, the coexistence of free radical and non-free radical reactions.

B, testing the performance of the boron-doped non-metal catalyst:

the catalytic degradation experiment was performed in a 150 mL conical flask, and a typical reaction system contained 0.2 g/L of catalyst, 10 mg/L of model contaminant phenol, 100 mL of solution volume, pH = 7, and 1 g/L of oxidant per sulfate (PMS). The reaction solution was sealed and placed in an incubator and the reaction was carried out at 25 ℃ with shaking at 120 rpm. After a certain time interval, 1 mL of the reaction mixture was removed and 0.5 mL of methanol was added, the catalyst was removed by filtration through a 0.22 μm membrane and measured by high performance liquid chromatography at 210 nm.

Catalytic degradation example 1: confirmation of catalytic Activity

Because the catalyst is a novel non-metallic carbon material catalyst, the carbon material per se has a certain adsorption effect on pollutants, and meanwhile, the oxidant PMS per se also has a certain oxidation capacity, in order to prove that the catalyst really has a catalytic effect, the catalyst prepared in example 1 is utilized, and the removal of phenol, which is a common pollutant, in a reaction system is compared under the conditions of oxidant blank (representing adsorption effect) and catalyst blank (representing oxidation effect of the oxidant). As can be seen from FIG. 7, under the conditions of adding the catalyst and PMS, the catalyst has a very high catalytic removal effect on phenol, which reaches more than 95% within 1h, while the adsorption under the same conditions is only 5.8%, and meanwhile, the degradation caused by the oxidant PMS itself is 1.7% under the condition without the catalyst, which indicates that the removal of phenol is completely caused by the degradation of catalyst activated PMS. To confirm that the activity of the catalyst is related to boron doping, we prepared a sample of comparative example 1 that was not doped. As can be seen from fig. 7, comparative example 1 has a significantly lower removal rate of phenol than example 1 under the same conditions, confirming the effectiveness of the doping effect.

Catalytic degradation example 2: demonstration of mineralization Capacity

In advanced oxidation reactions, the mineralization ability is also one of the important factors for evaluating catalytic oxidation performance. Mineralization capability is generally expressed in terms of Total Organic Carbon (TOC) removal rate, since this index can represent the processes of phenol ring opening cleavage to form small molecule acids followed by formation of carbon dioxide and water, inorganic salts, and the like. Too low an organic concentration, e.g. 10 mg/L, is highly inaccurate due to the TOC test principle, where 100 mg/L phenol is used in order to test the mineralization ability of the catalyst. As shown in fig. 8, the TOC removal rate for phenol was as high as 69.4% in 1 hour for example 1, while the sample prepared in comparative example 1 reached only 15.9% under the same conditions. This result not only indicates that phenol is mostly mineralized under catalytic action, but also reconfirms the effectiveness and superiority of boron doping.

Catalytic degradation example 3: influence of carbon Material Structure

The carbon material mainly comprises graphene and carbon nanotubes, wherein the carbon nanotubes comprise single-wall carbon nanotubes, double-wall carbon nanotubes and multi-wall carbon nanotubes. The carbon material has different parameters, wall thickness and pore size, and can affect the transfer of electrons on the carbon material and the generation of free radicals, thereby affecting the activity of the catalyst. As can be seen from the degradation curves of examples 1 to 8 in FIG. 9 for phenol, the catalysts all showed certain activity when the wall thickness of the carbon nanotubes ranged from 1-2 nm for single-walled carbon nanotubes to >50 nm for multi-walled carbon nanotubes, especially the activity was strongest when the diameter of the carbon nanotubes ranged from 10 to 20 nm, and was 8 to 15 nm. It is worth mentioning that single-walled carbon nanotubes are the most costly but the least active, probably because their surface energy is too high to agglomerate easily and thus agglomerate, reducing the surface area exposed to the reaction environment and thus reducing the catalytic activity.

Catalytic degradation example 4: effect of doping precursors

The doped element is boron (B), and the precursor comprises boric acid, borate and boron substituted organic matters containing different boron atoms. The doping effect of boron on the carbon material is influenced by different chemical environments of boron and different boron content in the precursor. As can be seen from fig. 10, example 1 and examples 9 to 12, the degradation effect of phenol is that, as the number of boron atoms in the precursor increases, the catalytic activity increases first and then decreases under the condition of the precursor with the same amount of substance, where the activity of 1, 4-phenyl diboronic acid containing two boron atoms in the precursor is the strongest, which indicates that the more boron atoms in the precursor, the higher the activity is, the boron atoms are doped on the carbon material has an upper doping limit, too much doping can seriously damage the carbon ring structure of the carbon nanotube, the original conjugated large pi bond is damaged, the free flow of electrons is affected, and therefore, the transfer of electrons between the catalyst and the oxidant is not facilitated, and the catalytic effect decreases.

Catalytic degradation example 5: influence of roasting gas atmosphere

The carbon material of the invention is doped with nitrogen (N)₂) Inert gas is used because the carbon material can better keep the original sp under the inert gas condition²And the carbon structure avoids the introduction of other elements except for the doping element. In a reducing gas such as hydrogen (H)₂) Under the condition, the activity of the doped carbon material is improved to a limited extent, which shows that the doped carbon material possibly reacts with the carbon material under the hydrogen atmosphere to change partial functional groups on the surface of the carbon material, so that the catalytic effect is reduced, and the hydrogen belongs to flammable and explosive gas and has safety risk in use. And oxygen (O) in an oxidizing gas such as air₂) At higher temperature, the carbon material reacts with oxygen to be oxidized into carbon dioxide, so that a large amount of carbon material is volatilized and lost, and the catalytic activity is greatly reduced (figure 11).

Catalytic degradation example 6: influence of calcination temperature

Since the surface structure of the material during calcination is dependent on the calcination temperature, the catalytic activity of the doped carbon material may vary depending on the calcination temperature. As can be seen from fig. 12, the activity of the catalysts of example 13 and comparative examples 4 to 9 prepared by the present invention is enhanced with the increase of temperature under the inert gas calcination atmosphere, and reaches the best at 800 ℃, and the catalytic activity is significantly reduced when the temperature is increased to 900 ℃, which indicates that the calcination temperature has a significant influence on the doping process, and the excessive temperature may cause the change of the physical structure of the carbon material and the chemical state of the doping element, thereby affecting the catalytic activity.

Catalytic degradation example 7: influence of oxidizing agent

In advanced oxidation reactions, common oxidants are similar and even sometimes can be used universally. For example, in the fenton-like reaction, the commonly used oxidizing agent is hydrogen peroxide and the hydroxyl radical formed by activation, while in the persulfate reaction, the commonly used oxidizing agent is persulfate and the hydroxyl radical and the sulfate radical formed by activation. Both hydrogen peroxide and persulfates have a peroxy bond and therefore are structurally similar and may also have similar characteristics in catalytic oxidation activity. The present invention was tested on hydrogen peroxide, peroxymonosulfate and peroxydisulfate using example 1 and figure 13 shows that the catalyst prepared according to the present invention has better catalytic degradation effect on both peroxymonosulfate and peroxydisulfate, but the catalytic effect on hydrogen peroxide is more general, probably because the structures of peroxymonosulfate and peroxydisulfate are closer.

Catalytic degradation example 8: influence of target contaminants

The catalyst prepared by the invention is used for advanced oxidative degradation of organic matters, the types of the organic matters are very wide, the degradation effects under the action of active species are also greatly different, in order to test the universality of pollutants applicable to the catalyst prepared by the invention, besides phenol, the invention also tests the dye rhodamine B, the cosmetic additive bisphenol S and the pesticide diuron in the example 1, and the test result is shown in a figure 14. The result shows that the green non-metal catalyst boron-doped multi-walled carbon nano tube prepared by the invention has good catalytic degradation removal effect on the pollutants, and the technology related by the invention is proved to have wider application range.

Finally, it should be noted that the above preferred embodiments are only intended to illustrate the technical solution of the present invention and not to limit it, and it should be understood that various changes in form and details can be made by those skilled in the art without inventive efforts. In general, various changes in form and detail may be made by those skilled in the art without departing from the scope of the invention as defined by the appended claims.

Claims

1. The preparation method of the boron-doped non-metallic catalyst is characterized by comprising the following steps of: adding a carbon material into an acid solution, heating and soaking for 0.5-24h at the temperature of 25-200 ℃, wherein the weight ratio of the carbon material to the acid solution is 1:1-1:500, filtering, washing with ultrapure water, and drying to obtain an intermediate 1; dispersing the intermediate 1 into a volatile solvent, adding a boron-containing precursor, heating in an oil bath, washing with ultrapure water after the reaction is finished, and drying to obtain an intermediate 2; and roasting the intermediate 2 for 0.5-6h at the temperature of 300-900 ℃ in a non-oxidizing atmosphere to obtain the boron-doped non-metal catalyst.

2. The method for preparing the boron-doped non-metallic catalyst according to claim 1, wherein the main components of the carbon material are graphene and carbon nanotubes, the graphene is high-purity graphene, graphene oxide or reduced graphene oxide, and the carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes or multi-walled carbon nanotubes.

3. The method of claim 2, wherein the multi-walled carbon nanotubes have a diameter of 2 to 50 nm.

4. The method of claim 1, wherein the volatile solvent is methanol, ethanol, water, acetonitrile, isopropanol, or cyclohexane.

5. The method for preparing the boron-doped non-metallic catalyst according to claim 1, wherein the boron-containing precursor is boric acid, borate or a boron-substituted organic substance containing any number of boron atoms.

6. The method of claim 1, wherein the non-oxidizing atmosphere is a non-oxidizing gas such as nitrogen, hydrogen, helium, or argon.

7. The method of claim 1, wherein the acid solution is nitric acid, sulfuric acid, hydrochloric acid, or phosphoric acid.

8. A boron-doped non-metallic catalyst prepared by the method of any one of claims 1 to 7.

9. The application of the boron-doped non-metallic catalyst in degrading organic pollutants in wastewater is characterized in that the boron-doped non-metallic catalyst is prepared by the preparation method of the boron-doped non-metallic catalyst as claimed in any one of claims 1 to 7.

10. The use of the boron-doped non-metallic catalyst in degrading organic pollutants in wastewater according to claim 9, wherein the wastewater is organic wastewater, the initial pH value is 3-11, and persulfate is added in the wastewater treatment process.