CN114733549A - Preparation method and application of double-nitrogen-group embedded carbon nano-framework - Google Patents
Preparation method and application of double-nitrogen-group embedded carbon nano-framework Download PDFInfo
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- CN114733549A CN114733549A CN202210427538.5A CN202210427538A CN114733549A CN 114733549 A CN114733549 A CN 114733549A CN 202210427538 A CN202210427538 A CN 202210427538A CN 114733549 A CN114733549 A CN 114733549A
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 118
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 117
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
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- 238000011069 regeneration method Methods 0.000 claims abstract description 38
- 238000004108 freeze drying Methods 0.000 claims abstract description 34
- BHXFKXOIODIUJO-UHFFFAOYSA-N benzene-1,4-dicarbonitrile Chemical compound N#CC1=CC=C(C#N)C=C1 BHXFKXOIODIUJO-UHFFFAOYSA-N 0.000 claims abstract description 32
- XNPMXMIWHVZGMJ-UHFFFAOYSA-N pyridine-2,6-dicarbonitrile Chemical compound N#CC1=CC=CC(C#N)=N1 XNPMXMIWHVZGMJ-UHFFFAOYSA-N 0.000 claims abstract description 31
- 230000001699 photocatalysis Effects 0.000 claims abstract description 20
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- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical group C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 description 17
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- YJLUBHOZZTYQIP-UHFFFAOYSA-N 2-[5-[2-(2,3-dihydro-1H-inden-2-ylamino)pyrimidin-5-yl]-1,3,4-oxadiazol-2-yl]-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethanone Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C1=NN=C(O1)CC(=O)N1CC2=C(CC1)NN=N2 YJLUBHOZZTYQIP-UHFFFAOYSA-N 0.000 description 2
- MYOXMAQGEINAEF-UHFFFAOYSA-N [C].N1=NN=CC=C1 Chemical compound [C].N1=NN=CC=C1 MYOXMAQGEINAEF-UHFFFAOYSA-N 0.000 description 2
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- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
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Images
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/32—Freeze drying, i.e. lyophilisation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
- B01J27/24—Nitrogen compounds
-
- B01J35/39—
-
- B01J35/60—
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
- B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation
- B01J37/343—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of ultrasonic wave energy
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/32—Hydrocarbons, e.g. oil
- C02F2101/327—Polyaromatic Hydrocarbons [PAH's]
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/34—Organic compounds containing oxygen
- C02F2101/345—Phenols
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/10—Photocatalysts
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Abstract
The invention discloses a preparation method and application of a double-nitrogen-group embedded carbon nano-framework. The structure regulation strategy is adopted to carry out the embedding of two nitrogen-containing groups: carrying out triazine group polymerization reaction on two precursors of 2, 6-pyridinedicarbonitrile and terephthalonitrile with different molar mass ratios to change the aperture and the specific surface area of the carbon nano-frame, promoting the migration and the widening of a lamellar stacking structure by adopting ultrasound and forming a plurality of channels to optimize the adsorption performance of the carbon nano-frame; meanwhile, the recombination of electrons and holes is inhibited by ultrasonic waves and pyridine groups embedded in the carbon nano-frame, the photoresponse range is widened, the photocatalytic activity of the carbon nano-frame is improved, the carbon nano-frame is fully dried by adopting a freeze drying technology, and meanwhile, the ultrasonic optimized structure is well maintained. The carbon nano-frame prepared by the invention has low price, the synthetic method is green and environment-friendly, and the carbon nano-frame can effectively enrich and concentrate organic pollutants and carry out photodegradation on the organic pollutants, simultaneously realizes self regeneration cycle, effectively prolongs the service cycle and reduces the cost.
Description
Technical Field
The invention belongs to the field of material preparation, and particularly relates to a preparation method and application of a double-nitrogen-group embedded carbon nano-framework.
Background
The adsorption method is widely applied as a main flow method for removing organic pollutants in water, but the organic pollutants are not really removed and even cause secondary pollution, so that the development of a material which has adsorption capacity and can realize photodegradation of the organic pollutants is a direction with great development prospect, and the material has the advantage of realizing the regeneration and cyclic utilization of the material. The emerging method is simple to operate, high in efficiency, green and environment-friendly, and has universality for treating polluted water bodies.
Carbon nano-frameworks with abundant porous structures and excellent physicochemical stability have recently been considered as a promising pollutant treatment material. The carbon nano-frame is formed by infinitely extending a series of highly conjugated units such as benzene rings, triazine rings and the like in a polymerization mode, has a certain pore structure, and is favorable for adsorbing organic pollutants. In addition, the carbon nano-framework has wider optical band gap, has a certain photoresponse range and has great application potential in the field of photocatalysis. However, many of the existing photocatalysts with adsorption property have a common problem that the adsorption sites and the photocatalytic sites interfere with each other to generate negative effects, which often cannot achieve ideal effects, and thus the regeneration property of the material is reduced. In order to solve the problem, the adsorption capacity and the photocatalytic activity of the material are improved at the same time, the regeneration and cyclic utilization of the material are realized, and the structure regulation becomes an effective means.
Chinese patent CN202110532349.X discloses a preparation method of a pyridine-rich cationic covalent triazine polymer. The preparation method comprises the step of calcining T-CN and anhydrous zinc chloride for 40 hours in a vacuum sealed container at high temperature (400 ℃, 500 ℃), although the material prepared in the patent has triazine groups and pyridine groups, the preparation method still needs vacuum and high temperature conditions and has certain potential safety hazard.
Disclosure of Invention
The invention aims to provide a preparation method and application of a double-nitrogen-group embedded carbon nano framework.
In order to reduce the negative influence generated by mutual interference of adsorption sites and photocatalytic sites and improve the adsorption capacity and photocatalytic activity, the invention adopts a brand new thought: the double-nitrogen-group embedded carbon nano-framework is prepared by mixing two precursors, namely 2, 6-pyridinedicarbonitrile and terephthalonitrile, according to a certain proportion, wherein after a triazine group formed by the cyano groups of the two precursors is subjected to polymerization reaction, the structure and the aperture of the carbon nano-framework can be adjusted, the specific surface area is increased, a lamellar stacking structure generated by combining an ultrasonic means is subjected to certain offset, the vertical distance between layers is widened, a plurality of channels are formed, the number and the exposure probability of adsorption sites are increased, and the adsorption performance of the carbon nano-framework is optimized; secondly, the ultrasonic wave can shift the lamellar structure of the carbon nano frame, the interlayer spacing is enlarged, the electron density of atoms in the molecular structure of the material is changed, and the hole distribution generated by optical excitation is changed along with the change of the electron density, so that the holes are not easy to be compounded with electrons, and meanwhile, the pyridine group is embedded in the carbon nano frame, so that the carbon nano frame is beneficial to adsorbing pollutants, the optical response range is widened, and the photocatalytic activity is improved; thirdly, compared with the conventional heating and drying method, the vacuum freeze drying method can effectively remove water on the surface of the carbon nano frame and in the pores and inorganic salt and other impurities dissolved in the water, under the condition of low temperature, the carbon nano frame is frozen, the volume is hardly changed, the laminated structure optimized by ultrasonic is maintained in the original form, and the adsorption and photocatalysis performance of the material are not influenced. Fourthly, the carbon nano-frame is synthesized by taking trifluoromethanesulfonic acid as a catalyst, so that energy waste and potential safety hazards under vacuum and high-temperature conditions are avoided, the material preparation period is greatly shortened, and the purpose of saving cost is achieved.
The technical scheme of the invention is as follows:
a preparation method of a double-nitrogen-group embedded carbon nano-framework comprises the following steps:
1) mixing 2, 6-pyridinedicarbonitrile and terephthalonitrile, adding the mixture into trifluoromethanesulfonic acid under the protection of low-temperature environment and inert gas atmosphere, and stirring to form uniform light yellow liquid;
2) carrying out ultrasonic treatment on the obtained light yellow liquid, then carrying out heating treatment, and cooling to obtain yellow crystals;
3) washing the yellow crystal alternately by using deionized water and acetone, carrying out solid-liquid separation, freeze-drying to constant weight, and grinding by using a mortar to obtain the double-nitrogen-group embedded carbon nano-frame;
the steps are all finished under normal pressure, and the mass ratio of the 2, 6-pyridinedicarbonitrile to the terephthalonitrile is controlled to be 0.5-3: 1.
Further, the temperature of the low-temperature environment in the step 1) is controlled to be-5 ℃, preferably 0 ℃, so as to prevent a large amount of heat from being released when the 2, 6-pyridinedicarbonitrile and the terephthalonitrile are dissolved in the trifluoromethanesulfonic acid.
Further, the ratio of the total amount of the 2, 6-pyridinedicarbonitrile and terephthalonitrile substances to the volume amount of the trifluoromethanesulfonic acid in the step 1) is controlled to be 1.0-2.0 mmol/mL, preferably 1.6mmol/mL, and the trifluoromethanesulfonic acid is used as two precursors of the 2, 6-pyridinedicarbonitrile and the terephthalonitrile to perform trimerization reaction to synthesize the double-nitrogen-group embedded carbon nano-frame, so that the material can be synthesized under mild conditions, and energy waste and potential safety hazards caused by a vacuum and high-temperature synthesis path are effectively avoided.
Further, in the process of stirring to form a light yellow liquid in the step 1), a constant-temperature water bath magnetic stirrer is used for stirring, and the rotating speed is controlled to be 600-1200 rpm, preferably 900 rpm; the stirring time is controlled to be 1-3 h, preferably 2h, so that the two precursors of 2, 6-pyridinedicarbonitrile and terephthalonitrile can be fully dissolved in trifluoromethanesulfonic acid, and the subsequent trimerization reaction for synthesizing the carbon nano-framework can be smoothly carried out.
Further, in the ultrasonic treatment process in the step 2), the temperature is constantly controlled to be 10-40 ℃, and preferably 30 ℃; the ultrasonic frequency is 20-80 kHz, and preferably 40 kHz; the ultrasonic treatment time is 20-60 min, preferably 40min, the ultrasonic is used as a key step for controlling the shape and structure of the double-nitrogen-group embedded carbon nano-framework, two precursors can be well and uniformly mixed with trifluoromethanesulfonic acid, the migration of a certain degree and the widening of the vertical distance between layers of the material sheet stacking structure are promoted, rich pore channels are generated, in addition, the electron density of atoms in the molecular structure of the material is changed, and the distribution of photo-generated holes generated by photocatalysis is changed; in the heating treatment process, the temperature is controlled to be 80-120 ℃, and preferably 100 ℃; the constant temperature time is controlled within 10-40 min, preferably 30min, the breakage and recombination of precursor molecular bonds occur in the process, and the micromolecules are polymerized again into the double-nitrogen-group embedded carbon nano-framework under the catalysis of the trifluoromethanesulfonic acid at high temperature.
Further, the solid-liquid separation process in the step 3) is carried out in a centrifugal machine, and the rotating speed is controlled to be 8000-12000 rpm, preferably 10000 rpm; the centrifugation time is controlled to be 3-8 min, preferably 5 min.
Further, the freeze drying process in the step 3) is carried out in a vacuum freeze dryer, and the freeze drying temperature is controlled to be-70 to-80 ℃, preferably-75 ℃; the freeze drying time is controlled within 20-30 h, preferably 24h, the freeze drying under the vacuum condition can change the water on the surface of the material and in the pores into solid water and sublimate in a very short time, impurities such as inorganic salt dissolved in the water can be removed together, the volume of the carbon nano frame is almost unchanged in the frozen state, the laminated structure after ultrasonic optimization is maintained, and the adsorption and photocatalysis performance of the laminated structure are not influenced.
The application of the double-nitrogen-group embedded carbon nano-frame in adsorption-photoregeneration catalytic degradation of aromatic pollutants in wastewater comprises the following steps:
1) adding the double-nitrogen-group embedded carbon nano-frame into aromatic pollutant wastewater, simultaneously placing the wastewater in a dark place for magnetic stirring for 60min to achieve adsorption-desorption balance, simulating sunlight conditions by using a metal halide lamp (400W), simultaneously performing photocatalytic pollutant degradation reaction by using magnetic stirring, periodically sampling, filtering by using a filter membrane, and detecting the residual concentration of the aromatic pollutants by using high performance liquid chromatography;
2) and (3) collecting the reacted double-nitrogen-group embedded carbon nano-frame, freeze-drying to constant weight, and repeating the experimental process of the step 1), wherein the step 1) is the 1 st round regeneration of the double-nitrogen-group embedded carbon nano-frame, and the number of the regeneration rounds is analogized.
Further, the aromatic pollutant is bisphenol A or naphthalene, and the concentration of the double-nitrogen-group embedded carbon nano-framework in the wastewater is 10-30 mg/L, preferably 20 mg/L.
The invention provides a mild synthesis method for carrying out structure regulation and embedding triazine groups and pyridine groups in two precursors, wherein a double-nitrogen-group embedded carbon nano-framework is prepared by utilizing key steps of ultrasound, freeze drying and the like, and has the following advantages in implementation and use:
1. compared with the common adsorbent, the double-nitrogen-group embedded carbon nano-frame has rich pore structure and large specific surface area, and has photocatalytic activity, so that organic pollutants can be effectively degraded; secondly, the double-nitrogen-group embedded carbon nano-framework adopts a structure regulation strategy, the triazine and pyridine groups embedded inside are beneficial to transmission of photo-generated electrons, and the high-conjugated structure of the double-nitrogen-group embedded carbon nano-framework has pi-pi accumulation effect with organic pollutants in water, especially with aromatic pollutants.
2. Compared with the traditional double-nitrogen-group embedding method, the double-nitrogen-group embedded carbon nano-frame disclosed by the invention has the advantages that the synthesis method is mild, the energy waste and potential safety hazards caused by vacuum and high-temperature conditions are avoided, the preparation period is greatly shortened, and the cost is low; meanwhile, the content of the dinitrogen group can be controlled by changing the proportion of the precursor.
3. Compared with the common laminated structure, the structure of the material is optimized by combining ultrasonic means, and the specific characteristics are that the vertical distance between layers in the laminated stacked structure is widened, the layers deviate to a certain degree, and multiple pore channels are formed, so that the number and the exposure probability of adsorption sites in the material sheet are improved, the electron density of atoms in the molecular structure of the material is changed, the hole distribution generated by light excitation is changed along with the change of the electron density, the recombination of electrons and photogenerated holes is inhibited, the adsorption performance and the photocatalytic activity are improved, the regeneration and cyclic utilization of the material can be realized, the utilization rate of the material is improved, and the cost is reduced.
4. Compared with the traditional heating drying, the invention adopts the vacuum freeze drying technology, the water molecules on the surface and in the inner pores of the material are sublimated at extremely low temperature in a short time, the complete drying of the material is achieved, meanwhile, the impurities such as inorganic salt dissolved in water are removed together, the volume of the material is expanded by the heating drying, and the structural appearance can be damaged to a certain extent.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) microscopic image of the double-nitrogen-group embedded carbon nano-framework prepared in example 1;
FIG. 2 is a scanning electron microscope image of the double nitrogen group embedded carbon nano-frame prepared in example 3;
FIG. 3 is a scanning electron microscope image of the double nitrogen group embedded carbon nano-frame prepared in example 5;
FIG. 4 is a transmission electron microscope image of the double nitrogen group embedded carbon nano-frame prepared in example 3.
Detailed Description
The invention is further described in the following with reference to the figures and examples in order to better understand the nature of the invention for those skilled in the art, but the scope of the invention is not limited thereto.
The process of embedding the double nitrogen groups in the carbon nano-framework comprises the following steps: mixing 2, 6-pyridinedicarbonitrile and terephthalonitrile according to a certain proportion, adding into certain volume of trifluoromethanesulfonic acid at 0 ℃ under the protection of nitrogen, and stirring at uniform speed by a magnetic stirrer to form a viscous and uniform solution. In each of the following examples, the method was used to achieve cleavage and recombination of precursor molecular bonds. However, it should be understood by those skilled in the art that the process of inserting the double nitrogen group into the carbon nano-frame is only a preferred mode of the present invention, and each parameter can be adjusted according to actual needs. The 2, 6-pyridinedicarbonitrile and terephthalonitrile in the precursor may be replaced, and other compounds having a cyano group and a pyridine group may be selected.
The optimization of the lamellar stacking structure of the double-nitrogen-group embedded carbon nano frame is promoted by an ultrasonic step, and the formation is particularly characterized in that certain offset occurs between lamellar layers, the vertical distance between the layers is widened, and multiple pore channels are formed in the lamellar stacking structure.
The polymerization process of the double-nitrogen-group embedded carbon nano-frame is carried out after the electric heating air blowing constant-temperature drying oven is heated and then is kept at a constant temperature for a certain time, and micromolecules are polymerized again into the double-nitrogen-group embedded carbon nano-frame under the catalysis of the trifluoromethanesulfonic acid at a high temperature.
The specific embodiment is as follows:
example 1
In this embodiment, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.3443g, 2.67mmol) and terephthalonitrile (0.6834g, 5.33mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Example 2
In this embodiment, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.4132g, 3.2mmol) and terephthalonitrile (0.6150g, 4.8mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be 30 ℃ constantly, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Example 3
In this embodiment, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Example 4
In this embodiment, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.6198g, 4.8mmol) and terephthalonitrile (0.4100g, 3.2mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, carrying out solid-liquid separation by using a centrifugal machine, wherein the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Example 5
In this embodiment, the specific steps for preparing the pyridine-modified renewable triazine carbon-based photocatalyst are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.6886g, 5.33mmol) and terephthalonitrile (0.3417g, 2.67mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be 30 ℃ constantly, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Example 6
In this embodiment, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.7747g, 6.0mmol) and terephthalonitrile (0.2563g, 2.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
In examples 1 to 6, the sum of the amounts of 2, 6-pyridinedicarbonitrile and terephthalonitrile was controlled to 8mmol, and the structure of the carbon nano-frame was controlled by changing the ratio of the two. The carbon nano-frames obtained in examples 1, 3 and 5 were subjected to electron microscope scanning, and the results thereof are shown in fig. 1, 2 and 3. As can be seen from the figure, the triazine group and the pyridine group are embedded into the carbon nano framework, so that more channels are generated in the laminated stacked structure of the carbon nano framework, the specific surface area of the material is increased, and the adsorption and photocatalysis performance of the material is improved. The excessive pyridine groups can cause a part of pyridine not to be embedded into the carbon nano framework structure, but to be accumulated on the surface of the carbon nano framework to cause the fragmentation of a part of the laminated stacked structure, and can also prevent light from reaching the carbon nano framework. Scanning the transmission electron microscope of example 3, it can be seen from fig. 4 that the material well forms a lamellar stack structure, the ultrasonic treatment promotes the deviation of lamellae and the widening of the vertical distance between layers, which is beneficial to the exposure of adsorption sites and photocatalytic sites, and the vacuum freeze-drying technology well maintains the structural morphology of the material after ultrasonic optimization.
In example 3, the ultrasonic and freeze-drying conditions in example 3 were varied to prepare a series of carbon nano-frameworks while controlling the sum of the amounts of 2, 6-pyridinedicarbonitrile and terephthalonitrile to 8mmol and the ratio of the amounts of the two substances to 1: 1.
The specific comparative examples are as follows:
comparative example 1
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(4) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(5) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(6) and then placing the separated solid in an oven, keeping the temperature at 60 ℃ for 24 hours continuously, and grinding the dried solid matter by using a mortar to obtain the double-nitrogen-group embedded carbon nano-frame.
Comparative example 2
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at the temperature of 0 ℃ in an ice-water bath under the protection of nitrogen atmosphere, and stirring at the rotating speed of 900rpm for 2 hours to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, carrying out solid-liquid separation by using a centrifugal machine, wherein the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in an oven, keeping the temperature at 60 ℃ for 24 hours continuously, and grinding the dried solid matter by using a mortar to obtain the double-nitrogen-group embedded carbon nano-frame.
Comparative example 3
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(4) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(5) then, carrying out solid-liquid separation by using a centrifugal machine, wherein the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(6) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Comparative example 4
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at the temperature of 0 ℃ in an ice-water bath under the protection of nitrogen atmosphere, and stirring at the rotating speed of 900rpm for 2 hours to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 20kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Comparative example 5
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be 30 ℃ constantly, controlling the ultrasonic frequency to be 80kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-75 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Comparative example 6
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at 0 ℃ in an ice-water bath under the protection of nitrogen, and stirring at 900rpm for 2h to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at the temperature of-70 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Comparative example 7
In this comparative example, the specific steps for preparing the dinitrogen-based embedded carbon nano-framework are as follows:
(1) adding 2, 6-pyridinedicarbonitrile (0.5165g, 4.0mmol) and terephthalonitrile (0.5125g, 4.0mmol) into a quartz tube with a rotor, and uniformly mixing by magnetic stirring;
(2) slowly adding 5.0 mL of trifluoromethanesulfonic acid into a quartz tube at the temperature of 0 ℃ in an ice-water bath under the protection of nitrogen atmosphere, and stirring at the rotating speed of 900rpm for 2 hours to form uniform light yellow liquid;
(3) putting the quartz tube into an ultrasonic machine, controlling the temperature to be constant at 30 ℃, controlling the ultrasonic frequency to be 40kHz, and carrying out ultrasonic treatment for 40 min;
(4) transferring to an electric heating constant temperature blast drying oven, heating to 100 deg.C, maintaining for 30min, and cooling to obtain yellow crystal;
(5) washing the obtained yellow crystal with deionized water and acetone alternately for 3 times;
(6) then, solid-liquid separation is carried out by using a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5 min;
(7) and then placing the separated solid in a vacuum freeze dryer, freeze-drying for 24h at-80 ℃, and grinding the dried solid matter by a mortar to obtain the double-nitrogen-group embedded carbon nano-framework.
Application example 1
Bisphenol A (BPA) is respectively subjected to adsorption-light regeneration catalytic degradation experiments under the irradiation of a metal halogen lamp by using the double-nitrogen-group embedded carbon nano-frames prepared in the examples 1 to 6 and the comparative examples 1 to 7, and the experiment steps are as follows: (1) in each set of experiments, 20mg of the double-nitrogen-group embedded carbon nano-frame prepared in the examples 1 to 6 was added into 100mL of wastewater with bisphenol A (BPA) concentration of 100ppm, and the wastewater was magnetically stirred in the dark for 60min to achieve adsorption-desorption equilibrium, then a metal halide lamp (400W) was used to simulate solar conditions, and the magnetic stirring was used to perform photocatalytic pollutant degradation reaction, and the samples were sampled at regular time and filtered through a 0.45 μm filter membrane, and the residual concentration of BPA was detected by high performance liquid chromatography; (2) and (3) collecting the reacted double-nitrogen-group embedded carbon nano-frame, freeze-drying the carbon nano-frame to constant weight (-75 ℃, 24h), and repeating the experimental process of the step (1).
The step (1) is the 1 st round of regeneration of the double-nitrogen-group embedded carbon nano-framework, and the like.
Application example 2
Naphthalene (NAP) is subjected to adsorption-light regeneration catalytic degradation experiments under the irradiation of a metal halide lamp by using the double-nitrogen-group embedded carbon nano-frames prepared in examples 1 to 6 and comparative examples 1 to 7, and the experimental steps are as follows: (1) in each experiment, 20mg of the pyridine-modified renewable triazine carbon-based photocatalyst prepared in examples 1 to 6 was added to 100mL of wastewater with a Naphthalene (NAP) concentration of 100ppm, and the wastewater was magnetically stirred in the dark for 60min to achieve adsorption-desorption equilibrium, then a metal halide lamp (400W) was used to simulate solar conditions, and the reaction for photocatalytic degradation of pollutants was performed with magnetic stirring, and then samples were taken at regular times and filtered with a 0.45 μm filter membrane, and the residual concentration of NAP was detected with high performance liquid chromatography; (2) and (3) collecting the reacted double-nitrogen-group embedded carbon nano-frame, freeze-drying the carbon nano-frame to constant weight (-75 ℃, 24h), and repeating the experimental process of the step (1).
The step (1) is the 1 st round of regeneration of the double-nitrogen-group embedded carbon nano-framework, and the like. The regeneration rate refers to the ratio of the adsorption capacity of the next round of material to the adsorption capacity of the previous round of material, in the invention, the regeneration rate is an important index for measuring the catalytic performance of material adsorption and light regeneration, and the first round regeneration rate is 100%.
The results after 6h of photocatalytic reaction are shown in tables 1 to 3, where table 1 is the degradation rate of the dinitrogen-based embedded carbon nano-framework prepared in examples 1 to 6 for the first round of regeneration experiments of bisphenol a (bpa) and Naphthalene (NAP), all examples achieve a degradation effect of more than 90% on two pollutants, example 3 has the best degradation effect on two pollutants, and particularly the degradation rate on NAP is as high as 95.6%. The double-nitrogen-group embedded carbon nano-frame synthesized by two precursors (2, 6-pyridinedicarbonitrile and terephthalonitrile) with different molar mass ratios can adsorb and degrade BPA and NAP and then carry out multiple rounds of regeneration, both have high regeneration rates, and each round of adsorption and degradation of NAP in each embodiment has the highest regeneration rate. In example 3, when the amount ratio of the 2, 6-pyridinedicarbonitrile to the terephthalonitrile was 1:1, the regeneration rate of the synthesized dinitrogen-group-embedded carbon nano-framework was the highest, the 2 nd to 4 th regeneration rates for adsorbing and degrading BPA were 98.1%, 97.1% and 95.0%, respectively, and the 2 nd to 4 th regeneration rates for adsorbing and degrading NAP were 98.9%, 98.4% and 95.1%, respectively. Therefore, the double-nitrogen-group embedded carbon nano-framework can adjust the regeneration rate by adjusting the ratio of the amounts of two precursor substances (2, 6-pyridinedicarbonitrile and terephthalonitrile).
TABLE 1 degradation ratio (%) -of first round regeneration experiments for adsorption of pollutants to be degraded by dinitrogen-based embedded carbon nano-frameworks with different molar ratios
| Contaminants | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 |
| BPA | 91.6 | 92.6 | 94.7 | 91.4 | 90.7 | 90.1 |
| NAP | 90.9 | 92.2 | 95.6 | 94.8 | 94.1 | 92.9 |
Table 2. double nitrogen group embedded carbon nano-frame with different molar ratios and 6h illumination, 4 regeneration rates (%)
| Number of regeneration rounds | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 |
| 1 st wheel | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
| |
95.3 | 96.8 | 98.1 | 94.6 | 92.3 | 90.9 |
| Wheel 3 | 93.4 | 95.1 | 97.1 | 93.2 | 91.8 | 89.3 |
| 4 th wheel | 90.5 | 92.0 | 95.0 | 90.3 | 89.5 | 88.2 |
Table 3. double nitrogen group embedded carbon nano-frame with different molar ratios and 6h illumination for adsorbing and degrading NAP 4 rounds of regeneration rate (%)
| Number of regeneration rounds | Example 1 | Example 2 | Practice ofExample 3 | Example 4 | Example 5 | Example 6 |
| 1 st wheel | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
| 2 nd wheel | 92.8 | 94.2 | 98.9 | 98.0 | 96.1 | 94.6 |
| Wheel 3 | 91.6 | 92.9 | 98.4 | 96.9 | 94.5 | 93.3 |
| 4 th wheel | 89.3 | 90.1 | 95.1 | 94.3 | 92.7 | 90.9 |
The results after 6h of photocatalytic reaction are shown in tables 4-6. Table 4 shows the degradation rate of the double-nitrogen-group embedded carbon nano-frame prepared in example 3 and comparative examples 1 to 7 for the first round of regeneration experiments of bisphenol a (bpa) and Naphthalene (NAP), and it can be seen that both ultrasonic treatment and freeze-drying treatment have certain influence on the adsorption degradation performance of the carbon nano-frame, and the importance of the two steps in the aspects of material structure optimization and maintenance is also confirmed. As can be seen from tables 5 and 6, when the conditions of ultrasound and freeze-drying in example 3 are changed, the synthesized double-nitrogen-group embedded carbon nano-framework is subjected to multiple cycles of regeneration after adsorbing and degrading bisphenol a (BPA) and Naphthalene (NAP), and compared with the carbon nano-framework synthesized in example 3, it is found that no ultrasound or freeze-drying is performed on BPA or NAP, so that the adsorption and photocatalytic performance of the material is greatly influenced, and the regeneration rate is obviously reduced. From the results of comparative example 1 and comparative example 2, it can be seen that ultrasound is a key step for optimizing the carbon nano framework structure, and is also a precondition for maintaining the morphology structure of the material by subsequent freeze drying. Comparing comparative example 1 with comparative example 3, it was found that freeze drying is a critical step in maintaining the structural morphology of the material, and has a large impact on the regeneration rate. From the regeneration rate results of comparative examples 4-7, it can be found that the regeneration rate is reduced to a certain extent by reducing or increasing the ultrasonic frequency, wherein the reduction of the frequency can cause insufficient ultrasonic energy and can not lead to better optimization of the material structure, and the increase of the frequency can cause overlarge offset degree of the lamellar structure and overlarge interlayer distance to influence the photocatalytic performance; in addition, the influence of the temperature change of freeze drying on the adsorption and photocatalytic performance of the material is far smaller than the influence brought by the change of ultrasonic frequency, when the temperature is higher, water molecules in deeper pores of the material cannot be better removed, and when the temperature is lower, the electronic activity of the material can be reduced.
TABLE 4 degradation Rate (%)
Table 5. double nitrogen group embedded carbon nano-frame illumination for 6h under different ultrasonic and freeze-drying conditions to adsorb and degrade 4 regeneration rates (%)
TABLE 6 4 regeneration rates (%)
The above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention. For example, the precursors used in the method for preparing the material in the above-mentioned examples are two kinds of 2, 6-pyridinedicarboxonitrile and terephthalonitrile, but it is not necessary to use these two precursors, and the effects of the present invention can be achieved as long as two precursors each having a cyano functional group are selected and can undergo polymerization to intercalate a triazine group, and at least one of them has a pyridine group. For example, the inert gas is nitrogen in the above examples, but it is not meant that nitrogen must be used for protection, and the materials can be successfully synthesized and the effect of the present invention can be achieved by using inert gas which can avoid oxidation of the raw materials during the reduction reaction.
It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the technical solutions obtained by means of equivalent substitution or equivalent transformation all fall within the protection scope of the present invention.
Claims (10)
1. A preparation method of a double-nitrogen-group embedded carbon nano-framework is characterized by comprising the following steps:
1) mixing 2, 6-pyridinedicarbonitrile and terephthalonitrile, adding the mixture into trifluoromethanesulfonic acid under the protection of low-temperature environment and inert gas atmosphere, and stirring to form uniform light yellow liquid;
2) carrying out ultrasonic treatment on the obtained light yellow liquid, then carrying out heating treatment, and cooling to obtain yellow crystals;
3) washing the yellow crystal alternately by using deionized water and acetone, carrying out solid-liquid separation, freeze-drying to constant weight, and grinding by using a mortar to obtain the double-nitrogen-group embedded carbon nano-frame;
the amount ratio of the 2, 6-pyridinedicarbonitrile to the terephthalonitrile is controlled to be 0.5-3: 1.
2. The method for preparing the double-nitrogen-group embedded carbon nano-frame according to claim 1, wherein the temperature of the low-temperature environment in the step 1) is controlled to be-5 ℃, preferably 0 ℃.
3. The method for preparing the double-nitrogen-group embedded carbon nano-framework as claimed in claim 1, wherein the ratio of the total amount of the 2, 6-pyridinedicarbonitrile and terephthalonitrile substances in the step 1) to the volume consumption of the trifluoromethanesulfonic acid is controlled to be 1.0-2.0 mmol/mL, preferably 1.6 mmol/mL.
4. The preparation method of the double-nitrogen-group embedded carbon nano-frame as claimed in claim 1, wherein in the process of stirring to form a light yellow liquid in the step 1), a constant-temperature water bath magnetic stirrer is used for stirring, and the rotation speed is controlled to be 600-1200 rpm, preferably 900 rpm; the stirring time is controlled to be 1-3 h, preferably 2 h.
5. The method for preparing the double-nitrogen-group embedded carbon nano-frame according to claim 1, wherein in the ultrasonic treatment process in the step 2), the temperature is constantly controlled to be 10-40 ℃, preferably 30 ℃; the ultrasonic frequency is 20-80 kHz, and preferably 40 kHz; the ultrasonic treatment time is 20-60 min, preferably 40 min; in the heating treatment process, the temperature is controlled to be 80-120 ℃, and preferably 100 ℃; the constant temperature time is controlled within 10-40 min, preferably 30 min.
6. The method for preparing the double-nitrogen-group embedded carbon nano-frame according to claim 1, wherein the solid-liquid separation process in the step 3) is performed in a centrifuge, and the rotation speed is controlled to be 8000-12000 rpm, preferably 10000 rpm; the centrifugation time is controlled to be 3-8 min, preferably 5 min.
7. The method for preparing the double-nitrogen-group embedded carbon nano-framework as claimed in claim 1, wherein the freeze-drying process in the step 3) is performed in a vacuum freeze-dryer, and the freeze-drying temperature is controlled to be-70 to-80 ℃, preferably-75 ℃; the freeze drying time is controlled to be 20-30 h, preferably 24 h.
8. The application of the double-nitrogen-group embedded carbon nano-frame in adsorption-photoregeneration catalytic degradation of aromatic pollutants in wastewater as claimed in claim 1, characterized by comprising the following steps:
1) adding the double-nitrogen-group embedded carbon nano-frame into aromatic pollutant wastewater, simultaneously placing the wastewater in a dark place for magnetic stirring for 60min to achieve adsorption-desorption balance, simulating solar conditions by using a metal halide lamp (400W), simultaneously performing photocatalytic pollutant degradation reaction by using magnetic stirring, periodically sampling, filtering by using a filter membrane, and detecting the residual concentration of the aromatic pollutants by using high performance liquid chromatography;
2) and (3) collecting the reacted double-nitrogen-group embedded carbon nano-frame, freeze-drying to constant weight, and repeating the experimental process of the step 1), wherein the step 1) is the 1 st round regeneration of the double-nitrogen-group embedded carbon nano-frame, and the number of the regeneration rounds is analogized.
9. The use of claim 8, wherein the aromatic contaminant is bisphenol a or naphthalene.
10. The use according to claim 8, wherein the concentration of the double nitrogen group embedded carbon nano-framework in wastewater is 10-30 mg/L, preferably 20 mg/L.
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| CN110075902A (en) * | 2019-05-22 | 2019-08-02 | 浙江工业大学 | A kind of deficiency covalent triazine frame material derived material catalyst and its preparation method and application |
| CN110479379A (en) * | 2019-08-28 | 2019-11-22 | 浙江工业大学 | A kind of covalent organic frame material catalyst and its preparation method and application based on load Ru nano particle |
| CN113666450A (en) * | 2021-08-16 | 2021-11-19 | 浙江工业大学 | Method for cooperatively treating low-concentration organic wastewater through adsorption and in-situ light regeneration |
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| CN110075902A (en) * | 2019-05-22 | 2019-08-02 | 浙江工业大学 | A kind of deficiency covalent triazine frame material derived material catalyst and its preparation method and application |
| CN110479379A (en) * | 2019-08-28 | 2019-11-22 | 浙江工业大学 | A kind of covalent organic frame material catalyst and its preparation method and application based on load Ru nano particle |
| CN113666450A (en) * | 2021-08-16 | 2021-11-19 | 浙江工业大学 | Method for cooperatively treating low-concentration organic wastewater through adsorption and in-situ light regeneration |
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