Carbon-based catalyst as well as preparation method and application thereof

Abstract

The invention specifically discloses a carbon-based catalyst as well as a preparation method and application thereof. The preparation method of the carbon-based catalyst comprises the following steps: carrying out high-temperature treatment on a carbon-based material in a carbonization atmosphere; the high-temperature treatment comprises the following steps: firstly heating the carbon-based material to 700-800 DEG C, preserving heat for 1-3 hours, then heating to 1000-1200 DEG C, and preserving heat for 0.5-6 hours to obtain the carbon-based catalyst; the carbon-based material comprises at least one of graphene, carbon black, activated carbon, diamond and biomass charcoal; the carbonization atmosphere comprises inert gas. The prepared carbon-based catalyst can efficiently purify waste water containing organic pollutants, the consumption of the oxidizing agent is small, the enrichment capacity of the pollutants is large, toxic by-products are not generated, the preparation cost is low, and the carbon-based catalyst can be applied to actual waste water treatment.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a carbon-based catalyst and a preparation method and application thereof. Background Art

[0002] With the development of industry, a wide variety of consumer products have emerged, inevitably leading to a surge in the amount of organic pollutants in urban wastewater. To date, advanced oxidation processes (AOPs), dominated by heterogeneous Fenton technology, have played an important role in the wastewater treatment industry due to their ability to effectively remove these organic pollutants.

[0003] AOP technology primarily relies on catalysts to activate oxidants to produce reactive oxygen species (ROS), such as superoxide, hydroxyl radicals, and singlet oxygen. These ROS attack organic pollutants, degrading and mineralizing them, thereby achieving water purification. However, this reaction mechanism, which requires a catalyst to efficiently activate the oxidant to produce ROS species, places extremely high demands on the catalyst's performance. Consequently, developed catalysts are often costly and unstable, making them difficult to widely use in actual wastewater treatment. Summary of the Invention

[0004] In order to efficiently purify wastewater containing organic pollutants, the present application provides a carbon-based catalyst and its preparation method and application.

[0005] In a first aspect, the present application provides a method for preparing a carbon-based catalyst, which adopts the following technical solution:

[0006] A method for preparing a carbon-based catalyst comprises the following steps:

[0007] subjecting the carbon-based material to high-temperature treatment in a carbonizing atmosphere;

[0008] The high temperature treatment comprises the following steps: first heating the carbon-based material to 700-800° C., keeping the temperature for 1-3 hours, then heating the material to 1000-1200° C., keeping the temperature for 0.5-6 hours, to obtain the carbon-based catalyst;

[0009] The carbon-based material includes at least one of graphene, carbon black, activated carbon, diamond, and biochar;

[0010] The carburizing atmosphere includes an inert gas.

[0011] The present invention adjusts the oxygen content of the carbon-based material to a suitable stage by first performing a high-temperature treatment operation in stages, which helps the carbon-based material to form a stable sp 2 Carbon Network, sp 2The electron transfer characteristics of the carbon network can cause organic pollutants and oxidants to undergo oxidative polymerization on the surface of the carbon-based catalyst, which is the direct oxidation transfer process (DOTP), so that the organic pollutants are enriched on the surface of the carbon-based catalyst. Compared with the catalysts in the prior art that mainly decompose organic pollutants, the carbon-based catalyst prepared in this application, when used in the treatment of wastewater containing organic pollutants, has a low consumption of oxidants, a large pollutant enrichment capacity, does not produce toxic by-products, and has a low preparation cost. It can be widely used in the actual treatment of wastewater containing organic pollutants.

[0012] Preferably, the biomass charcoal includes at least one of sludge charcoal, sawdust, rice husk, and circuit board charcoal.

[0013] Preferably, the inert gas includes at least one of nitrogen or argon.

[0014] Preferably, the oxygen content of the carbon-based material is less than 15 wt%.

[0015] This application helps carbon-based catalysts build a stable sp by selecting carbon-based materials with appropriate oxygen content. 2 carbon network, thereby enhancing its effect in promoting the oxidative polymerization of organic pollutants and polymers on the catalyst surface.

[0016] Preferably, during the high-temperature treatment, the inert gas has a flow rate of 80-200 mL / min.

[0017] Preferably, in the high temperature treatment, the temperature rise gradient of the first heating is 5-8°C / min, and the temperature rise gradient of the second heating is 6-10°C / min.

[0018] Preferably, the carbonization atmosphere further includes ammonia.

[0019] The present invention can introduce carbon-nitrogen covalent bonds into the final carbon-based catalyst by introducing ammonia, and the carbon-nitrogen covalent bonds can form carbon-nitrogen bonds with sp 2 The carbon network is coordinated to improve the adsorption capacity of the carbon-based catalyst for organic pollutants and oxidants, thereby significantly improving the removal effect of the carbon-based catalyst on organic pollutants.

[0020] Preferably, the carbon-based material is pretreated before the high-temperature treatment, and the pretreatment includes the following steps:

[0021] The ammonia and the inert gas are introduced into the carbon-based material, and the temperature is raised to 200-400° C. and kept warm for 0.5-1 hour, and then raised to 400-600° C. and kept warm for 0.5-1 hour to obtain a pretreated carbon-based material.

[0022] Preferably, in the process of introducing the ammonia gas and the inert gas into the carbon-based material, the temperature rise gradient of the first heating is 3-5°C / min, and the temperature rise gradient of the second heating is 5-8°C / min.

[0023] Preferably, in the pretreatment, the gas flow rate of the ammonia gas is 20-30 mL / min, and the gas flow rate of the inert gas is 60-160 mL / min.

[0024] Preferably, in the pretreatment, the ratio of the gas flow rate of the ammonia gas to the gas flow rate of the inert gas is 1:(3-5).

[0025] The present invention controls the flow rate of ammonia and inert gas in the carbonizing atmosphere to adjust the ratio of carbon-nitrogen covalent bonds introduced into the carbon-based catalyst. When the number of carbon-nitrogen covalent bonds is too large, the effect of the carbon-based catalyst in removing organic pollution will be inhibited to a certain extent. When the number of carbon-nitrogen covalent bonds is too small, the effect of carbon-nitrogen covalent bonds on improving the removal of organic matter by the carbon-based catalyst is limited. Therefore, the introduction of ammonia and inert gas simultaneously within the above-mentioned gas flow range can make the carbon-nitrogen covalent bonds and sp in the carbon-based catalyst more stable. 2 The carbon network forms a good coordination effect, thereby significantly improving the removal effect of carbon-based catalysts on organic pollutants.

[0026] In a second aspect, the present application provides a carbon-based catalyst, which adopts the following technical solution:

[0027] A carbon-based catalyst is prepared by the method described above.

[0028] In a third aspect, the present application provides an application of a carbon-based catalyst in treating wastewater containing organic pollutants, using the following technical solution:

[0029] A method for treating wastewater containing organic pollutants using a carbon-based catalyst comprises the following steps:

[0030] The carbon-based catalyst is mixed with wastewater containing organic pollutants to obtain a mixed solution, and an oxidant is added to the mixed solution to obtain purified wastewater;

[0031] Wherein, the concentration of organic pollutants contained in the organic pollutant wastewater is 0.01-0.25 g / L; the organic pollutants include at least one of phenol, aniline, and bisphenol A;

[0032] The oxidant includes at least one of persulfate, hydrogen peroxide, and peracetic acid.

[0033] Preferably, the concentration of the oxidant in the mixed solution is 0.133-1.33 mmol / L; the dosage of the carbon-based catalyst in the mixed solution is 0.1-1 g / L.

[0034] The carbon-based catalyst of the present application is used to treat wastewater containing organic pollutants, and the removal rate of the target organic pollutants reaches 100%, and the required oxidant is only twice the amount of the target organic pollutants. DETAILED DESCRIPTION

[0035] For better understanding and implementation, the technical solution of the present application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0037] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties sought to be obtained.

[0038] As used herein, "and / or" means one or all of the mentioned elements.

[0039] As used herein, “including” and “comprising” encompasses the case where only the stated elements are present and also the case where there are other elements other than the stated elements.

[0040] All percentages in this application are by weight unless otherwise stated.

[0041] Unless otherwise indicated, as used in this specification, "a," "an," "an," and "the" are intended to include "at least one" or "one or more." For example, "a component" refers to one or more components, and thus more than one component is contemplated and may be employed or used in the practice of the described embodiment.

[0042] Example 1

[0043] 1. Preparation of carbon-based catalysts

[0044] (1) Grinding the nanodiamond into powder and drying;

[0045] (2) The powder obtained in step (1) was evenly spread in a magnetic boat, and then the magnetic boat was placed in a tube furnace. After the tube was evacuated with an air pump, nitrogen was continuously passed through for 1 hour to ensure that there was no air in the tube furnace;

[0046] (3) The tube furnace was heated to 800°C at a heating rate of 8°C / min and kept at this temperature for 1 h. The temperature was then increased to 1200°C at a heating rate of 10°C / min and kept at this temperature for 0.5 h. During this period, nitrogen gas was kept flowing at a nitrogen flow rate of 120 mL / min.

[0047] (4) Step (3) is completed and cooled to room temperature to obtain a carbon-based catalyst. The sp 2 Carbon / sp 3 Carbon is 1.1.

[0048] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0049] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0050] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0051] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.2 mM;

[0052] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0053] Example 2

[0054] 1. Preparation of carbon-based catalysts

[0055] (1) Spread the graphene oxide powder evenly in a magnetic boat, then place the magnetic boat in a tube furnace. After the tube is evacuated with an air pump, nitrogen is continuously passed through for 1 hour to ensure that there is no air in the tube furnace.

[0056] (2) The tube furnace was heated to 700°C at a heating rate of 5°C / min and kept at this temperature for 3 h. The temperature was then increased to 1000°C at a heating rate of 6°C / min and kept at this temperature for 6 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 200 mL / min.

[0057] (3) Step (2) is completed and cooled to room temperature to obtain a carbon-based catalyst.

[0058] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0059] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0060] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0061] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.266 mM;

[0062] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0063] Example 3

[0064] 1. Preparation of carbon-based catalysts

[0065] (1) Grind the sludge into powder, sieve it with a 150-mesh sieve and dry it;

[0066] (2) The powder obtained in step (1) was evenly spread in a magnetic boat, and then the magnetic boat was placed in a tube furnace. After the tube was evacuated with an air pump, nitrogen was continuously passed through for 1 hour to ensure that there was no air in the tube furnace;

[0067] (3) The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 10°C / min and kept at this temperature for 3 h. During this period, nitrogen was kept flowing at a nitrogen flow rate of 160 mL / min.

[0068] (4) Step (3) is completed and cooled to room temperature to obtain a carbon-based catalyst.

[0069] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0070] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0071] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0072] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.266 mM;

[0073] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0074] Example 4

[0075] 1. Preparation of carbon-based catalysts

[0076] (1) Grind the sludge into powder, sieve it with a 150-mesh sieve and dry it;

[0077] (2) The powder obtained in step (1) was evenly spread in a magnetic boat, and then the magnetic boat was placed in a tube furnace. After the tube was evacuated with an air pump, nitrogen was continuously passed through for 1 hour to ensure that there was no air in the tube furnace;

[0078] (3) heating the tubular furnace to 300°C at a heating rate of 4°C / min, holding the temperature for 0.6h, and then heating the tubular furnace to 500°C at a heating rate of 6°C / min, holding the temperature for 0.9h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as the nitrogen source, the gas flow rate of ammonia was 25mL / min, and the gas flow rate of nitrogen was 100mL / min, to obtain a pretreated carbon-based material;

[0079] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0080] (4) Step (3) is completed and cooled to room temperature to obtain a carbon-based catalyst.

[0081] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0082] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0083] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0084] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.266 mM;

[0085] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0086] Example 5

[0087] 1. Preparation of carbon-based catalysts

[0088] (1) Grind the sludge into powder, sieve it with a 150-mesh sieve and dry it;

[0089] (2) The powder obtained in step (1) was evenly spread in a magnetic boat, and then the magnetic boat was placed in a tube furnace. After the tube was evacuated with an air pump, nitrogen was continuously passed through for 1 hour to ensure that there was no air in the tube furnace;

[0090] (3) heating the tube furnace to 400°C at a heating rate of 5°C / min, holding the temperature for 0.5h, and then heating the tube furnace to 600°C at a heating rate of 8°C / min, holding the temperature for 0.5h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as the nitrogen source, the gas flow rate of ammonia was 20mL / min, and the gas flow rate of nitrogen was 160mL / min, to obtain a pretreated carbon-based material;

[0091] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0092] (4) Step (3) is completed and cooled to room temperature to obtain a carbon-based catalyst.

[0093] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0094] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0095] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0096] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.266 mM;

[0097] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0098] Example 6

[0099] 1. Preparation of carbon-based catalysts

[0100] (1) Grind the sludge into powder, sieve it with a 150-mesh sieve and dry it;

[0101] (2) The powder obtained in step (1) was evenly spread in a magnetic boat, and then the magnetic boat was placed in a tube furnace. After the tube was evacuated with an air pump, nitrogen was continuously passed through for 1 hour to ensure that there was no air in the tube furnace;

[0102] (3) heating the tubular furnace to 300°C at a heating rate of 3°C / min, holding the temperature for 0.8h, and then heating the tubular furnace to 400°C at a heating rate of 5°C / min, holding the temperature for 1h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as the nitrogen source, the gas flow rate of ammonia was 30mL / min, and the gas flow rate of nitrogen was 60mL / min, to obtain a pretreated carbon-based material;

[0103] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0104] (4) Step (3) is completed and cooled to room temperature to obtain a carbon-based catalyst.

[0105] 2. Application of carbon-based catalysts in treating wastewater containing organic pollutants

[0106] (1) Weigh 4 mg of the above carbon-based catalyst, ultrasonically disperse it in 20 mL of phenol solution (phenol concentration is 12.5 mg / L), and magnetically stir for 5 h for pre-adsorption. The stirring speed is maintained at 300 r / min to obtain a mixed solution;

[0107] (2) After the pre-adsorption of step (1) is completed, 1 mL of the mixed solution sample is taken out with a pipette and placed into a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution);

[0108] (3) Add persulfate (PDS) solution to the centrifuge tube to make the PDS concentration in the system 0.266 mM;

[0109] (4) At 2 min, 4 min, 10 min, 18 min, 30 min, 44 min, and 60 min after adding PDS, 1 mL of solution sample was taken with a pipette and placed in a 2 mL centrifuge tube (containing 100 μL of 0.1 M ascorbic acid solution) for storage; purified wastewater was obtained.

[0110] Example 7

[0111] The difference between this embodiment and embodiment 4 is that the high temperature treatment process includes the following steps:

[0112] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept warm for 2 hours, and then heated to 1100°C at a heating rate of 8°C / min and kept warm for 3 hours, during which nitrogen was kept flowing at a nitrogen gas flow rate of 160 mL / min to obtain a pretreated carbon-based material;

[0113] The tube furnace was heated to 300°C at a heating rate of 4°C / min and kept at this temperature for 0.6 h. The temperature was then increased to 500°C at a heating rate of 6°C / min and kept at this temperature for 0.9 h. During this period, nitrogen and ammonia gases were kept flowing, with ammonia being used as the nitrogen source, the gas flow rate of ammonia being 25 mL / min, and the gas flow rate of nitrogen being 160 mL / min.

[0114] Other steps and parameter settings are consistent with Example 4.

[0115] Example 8

[0116] The difference between this embodiment and embodiment 4 is that the high temperature treatment process includes the following steps:

[0117] The tube furnace was heated to 300°C at a heating rate of 4°C / min, kept warm for 0.6h, and then heated to 500°C at a heating rate of 6°C / min, kept warm for 0.9h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as a nitrogen source, the gas flow rate of ammonia was 25mL / min, and the gas flow rate of nitrogen was 75mL / min, to obtain a pretreated carbon-based material;

[0118] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0119] Other steps and parameter settings are consistent with Example 4.

[0120] Example 9

[0121] The difference between this embodiment and embodiment 4 is that the high temperature treatment process includes the following steps:

[0122] The tube furnace was heated to 300°C at a heating rate of 4°C / min, kept warm for 0.6h, and then heated to 500°C at a heating rate of 6°C / min, kept warm for 0.9h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as a nitrogen source, the gas flow rate of ammonia was 25mL / min, and the gas flow rate of nitrogen was 125mL / min, to obtain a pretreated carbon-based material;

[0123] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0124] Other steps and parameter settings are consistent with Example 4.

[0125] Example 10

[0126] The difference between this embodiment and embodiment 4 is that the high temperature treatment process includes the following steps:

[0127] The tube furnace was heated to 300°C at a heating rate of 3°C / min, kept warm for 1 hour, and then heated to 500°C at a heating rate of 6°C / min, kept warm for 3 hours, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as a nitrogen source, the gas flow rate of ammonia was 15 mL / min, and the gas flow rate of nitrogen was 30 mL / min, to obtain a pretreated carbon-based material;

[0128] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0129] Other steps and parameter settings are consistent with Example 4.

[0130] Example 11

[0131] The difference between this embodiment and embodiment 4 is that the high temperature treatment process includes the following steps:

[0132] The tube furnace was heated to 300°C at a heating rate of 4°C / min, kept warm for 0.6h, and then heated to 500°C at a heating rate of 6°C / min, kept warm for 0.9h, during which nitrogen and ammonia gases were kept flowing, wherein ammonia was used as a nitrogen source, the gas flow rate of ammonia was 25mL / min, and the gas flow rate of nitrogen was 200mL / min, to obtain a pretreated carbon-based material;

[0133] The tube furnace was heated to 750°C at a heating rate of 6°C / min and kept at this temperature for 2 h. The temperature was then increased to 1100°C at a heating rate of 8°C / min and kept at this temperature for 3 h. During this period, nitrogen gas was kept flowing at a gas flow rate of 160 mL / min.

[0134] Other steps and parameter settings are consistent with Example 4.

[0135] Example 12

[0136] The difference between this embodiment and embodiment 4 is that the oxygen content of the carbon-based material is 30 wt %; other steps and parameter settings are consistent with those of embodiment 4.

[0137] Comparative Example 1

[0138] The difference between this comparative example and Example 1 is that nanodiamond is used instead of the carbon-based catalyst in Example 1; the other steps and parameter settings are consistent with Example 1. 2 Carbon / sp 3 Carbon is 0.2.

[0139] Comparative Example 2

[0140] The difference between this comparative example and Example 1 is that graphene oxide powder is used instead of the carbon-based catalyst in Example 1; other steps and parameter settings are consistent with Example 1.

[0141] Comparative Example 3

[0142] The difference between this comparative example and Example 1 is that sludge carbon is used instead of the carbon-based catalyst in Example 1; other steps and parameter settings are consistent with Example 1.

[0143] Comparative Example 4

[0144] The difference between this comparative example and Example 1 is that, in the process of treating wastewater containing organic pollutants, nano zero-valent iron of equal mass concentration is used instead of the carbon-based catalyst in Example 1; the other steps and parameter settings are consistent with Example 1.

[0145] Comparative Example 5

[0146] The difference between this comparative example and Example 1 is that, in the preparation process of the carbon-based catalyst, step (3) is to heat the tubular furnace to 1200°C at a heating rate of 10°C / min and keep it warm for 1.5 hours, during which nitrogen is kept flowing, and the nitrogen gas flow rate is 120 mL / min; the other steps and parameter settings are consistent with Example 1.

[0147] Test Method

[0148] 1. Phenol concentration test

[0149] The purified wastewater obtained in the above examples and comparative examples was tested for phenol concentration. The specific test steps were as follows: all samples were filtered with a 0.22 μm filter membrane, and the phenol concentration of each sample was measured by ultra-performance liquid chromatography (UPLC).

[0150] 2. Aniline concentration test

[0151] The purified wastewater obtained in the above examples and comparative examples was tested for aniline concentration. The specific test steps were as follows: all samples were filtered with a 0.22 μm filter membrane, and the phenol concentration of each sample was measured by ultra-performance liquid chromatography (UPLC).

[0152] 3. Bisphenol A concentration test

[0153] The purified wastewater obtained in the above examples and comparative examples was tested for bisphenol A concentration. The specific test steps were as follows: all samples were filtered with a 0.22 μm filter membrane, and the phenol concentration of each sample was measured by ultra-performance liquid chromatography (UPLC).

[0154] 4. Oxygen content test in carbon-based catalysts

[0155] The carbon-based catalysts obtained in the above examples and comparative examples were analyzed using X-ray photoelectron spectroscopy (XPS). Full spectra and high-resolution O1s spectra (525-540 eV, step size 0.1 eV) were collected under ultra-high vacuum conditions. After correcting the binding energy using the contaminating carbon peak (C1s, 284.8 eV) as a reference, characteristic peaks such as CO (531-533 eV), C=O (533-534 eV), and OC=O (534-536 eV) were analyzed. Shirley background was subtracted and the total peak area was integrated. The oxygen content was calculated by combining the oxygen sensitivity factor (2.93) with the peak area of ​​each element according to the formula: oxygen content (wt%) = (O1s peak area / 2.93) / [Σ(peak area of ​​each element / corresponding factor)] × 100%.

[0156] Table 1 Related performance tests of Examples 1 to 12 and Comparative Examples 1 to 5

[0157]

[0158] The relevant performance test results of Examples 1-12 and Comparative Examples 1-5 are shown in Table 1. As can be seen from Table 1, the catalytic performance of the carbon-based catalysts provided by Examples 1-12 is better than that of Comparative Examples 1-5.

[0159] Among them, comparative examples 1 to 3 respectively used nanodiamonds, graphene oxide powder, and sludge carbon without pretreatment and high temperature treatment to treat wastewater containing organic pollutants. The above carbon-based materials were not treated at high temperature and did not form a stable sp 2 Carbon network, resulting in poor conductivity and poor catalytic performance; Comparative Example 4 uses nano-zero-valent iron to treat wastewater containing organic pollutants, and the catalyst removes organic pollutants in the wastewater through the action of AOP (it should be noted that the nano-zero-valent iron used in Comparative Example 4 is reduced iron powder, so the oxygen content is 0); The carbon-based catalyst provided in Comparative Example 5 does not have segmented heating in the high-temperature treatment step of the preparation process, and the oxygen content of the carbon-based material cannot be adjusted to the appropriate stage, and a stable sp 2 Therefore, it is shown that the present invention adjusts the oxygen content of the carbon-based material to a suitable stage by first performing a segmented high-temperature treatment operation, which helps the carbon-based material to form a stable sp in the subsequent heating process. 2 Carbon Network, sp 2The electron transfer characteristics of the carbon network can cause organic pollutants and oxidants to undergo oxidative polymerization on the surface of the carbon-based catalyst, which is the direct oxidation transfer process (DOTP), so that the organic pollutants are enriched on the surface of the carbon-based catalyst. Compared with the catalysts in the prior art that mainly decompose organic pollutants, the carbon-based catalyst prepared in this application, when used in the treatment of wastewater containing organic pollutants, has a low consumption of oxidants, a large pollutant enrichment capacity, does not produce toxic by-products, and has a low preparation cost. It can be widely used in the actual treatment of wastewater containing organic pollutants.

[0160] Combining Examples 3-7 and Table 1, it can be seen that the removal rate of organic pollutants in Examples 4-6 after 10 minutes of reaction is higher than that in Example 3. The reason is that, in Examples 4-6, a pretreatment step is added before the high-temperature treatment step in the carbon-based catalyst preparation process to introduce ammonia; the removal rate of organic pollutants in Example 7 after 10 and 60 minutes of reaction is worse than that in Example 4. The reason is that, in Example 7, nitrogen is first introduced in the pretreatment step in the carbon-based catalyst preparation process, and ammonia and nitrogen are introduced in the high-temperature treatment step. This shows that the present application can introduce carbon-nitrogen covalent bonds in the final carbon-based catalyst by introducing ammonia, and the carbon-nitrogen covalent bonds can react with sp in the carbon-based catalyst. 2 The carbon network is coordinated to improve the adsorption capacity of the carbon-based catalyst for organic pollutants and oxidants, thereby significantly improving the removal effect of the carbon-based catalyst on organic pollutants.

[0161] In combination with Examples 4, 8-11 and Table 1, it can be seen that when the flow rate value of ammonia and inert gas is controlled at 1: (3-5), the degradation rate of the obtained carbon-based catalyst when participating in the degradation reaction of wastewater containing organic pollutants is higher, that is, when the flow rate value of ammonia and inert gas is controlled at 1: (3-5), the catalytic performance of the obtained carbon-based catalyst is better, indicating that the present application controls the flow rate of ammonia and inert gas in the carbonizing atmosphere, and can adjust the ratio of carbon-nitrogen covalent bonds introduced into the carbon-based catalyst. When the number of carbon-nitrogen covalent bonds is too much, it will inhibit the effect of the carbon-based catalyst in removing organic pollution to a certain extent, and when the number of carbon-nitrogen covalent bonds is too small, the effect of carbon-nitrogen covalent bonds on improving the removal of organic matter by the carbon-based catalyst is limited. Therefore, introducing ammonia and inert gas at the same time within the above-mentioned gas flow range can make the carbon-nitrogen covalent bonds and sp in the carbon-based catalyst more stable. 2 The carbon network forms a good coordination effect, thereby significantly improving the removal effect of carbon-based catalysts on organic pollutants.

[0162] Combining Examples 1 and 12 with Table 1, it can be seen that the oxygen content of the carbon-based material used in Example 12 is 30 wt%. When treating wastewater containing organic pollutants, the organic pollutant removal rate is worse than that in Example 1, indicating that the present application helps the carbon-based catalyst to build a stable sp by selecting a carbon-based material with a suitable oxygen content. 2carbon network, thereby enhancing its effect in promoting the oxidative polymerization of organic pollutants and polymers on the catalyst surface.

[0163] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the technical solutions of the present application can be modified or replaced by equivalents, but these modifications or replacements are all within the scope of protection of the present application.

Claims

1. A method for preparing a carbon-based catalyst, characterized in that: The steps include: subjecting the carbon-based material to high-temperature treatment in a carbonizing atmosphere; The high temperature treatment comprises the following steps: first heating the carbon-based material to 700-800° C., keeping the temperature for 1-3 hours, then heating the material to 1000-1200° C., keeping the temperature for 0.5-6 hours, to obtain the carbon-based catalyst; The carbon-based material includes at least one of graphene, carbon black, activated carbon, diamond, and biochar; The carburizing atmosphere includes an inert gas.

2. The method for preparing a carbon-based catalyst according to claim 1, wherein: The oxygen content of the carbon-based material is less than 15 wt %.

3. The method for preparing a carbon-based catalyst according to claim 1, wherein: During the high-temperature treatment, the inert gas has a flow rate of 80-200 mL / min.

4. The method for preparing a carbon-based catalyst according to claim 1, wherein: The carbonization atmosphere also includes ammonia.

5. The method for preparing a carbon-based catalyst according to claim 4, wherein: The carbon-based material is also pretreated before the high-temperature treatment, and the pretreatment includes the following steps: The ammonia and the inert gas are introduced into the carbon-based material, and the temperature is raised to 200-400° C. and kept warm for 0.5-1 hour, and then raised to 400-600° C. and kept warm for 0.5-1 hour to obtain a pretreated carbon-based material.

6. The method for preparing a carbon-based catalyst according to claim 5, characterized in that: During the pretreatment, the gas flow rate of the ammonia gas is 20-30 mL / min, and the gas flow rate of the inert gas is 60-160 mL / min.

7. The method for preparing a carbon-based catalyst according to claim 6, characterized in that: In the pretreatment, the ratio of the gas flow rate of the ammonia gas to the gas flow rate of the inert gas is 1:(3-5).

8. A carbon-based catalyst, characterized in that: The method is prepared by the method according to any one of claims 1 to 7.

9. Use of a carbon-based catalyst in treating wastewater containing organic pollutants, characterized in that: The application of the carbon-based catalyst in treating wastewater containing organic pollutants comprises the following steps: mixing the carbon-based catalyst according to claim 8 with wastewater containing organic pollutants to obtain a mixed solution, and adding an oxidant to the mixed solution to obtain purified wastewater; Wherein, the concentration of organic pollutants contained in the organic pollutant wastewater is 0.01-0.25 g / L; the organic pollutants include at least one of phenol, aniline, and bisphenol A; The oxidant includes at least one of persulfate, hydrogen peroxide, and peracetic acid.

10. Use of a carbon-based catalyst in treating wastewater containing organic pollutants, characterized in that: The concentration of the oxidant in the mixed solution is 0.133-1.33 mmol / L; the dosage of the carbon-based catalyst in the mixed solution is 0.1-1 g / L.

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