CN114733549B - Preparation method and application of dinitrogen group embedded carbon nano-frame - Google Patents
Preparation method and application of dinitrogen group embedded carbon nano-frame Download PDFInfo
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- CN114733549B CN114733549B CN202210427538.5A CN202210427538A CN114733549B CN 114733549 B CN114733549 B CN 114733549B CN 202210427538 A CN202210427538 A CN 202210427538A CN 114733549 B CN114733549 B CN 114733549B
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- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 113
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 112
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical group N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 62
- 238000002360 preparation method Methods 0.000 title claims abstract description 14
- 238000011069 regeneration method Methods 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 36
- 230000008929 regeneration Effects 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
- 238000004108 freeze drying Methods 0.000 claims abstract description 31
- 230000001699 photocatalysis Effects 0.000 claims abstract description 19
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 claims description 38
- 239000007788 liquid Substances 0.000 claims description 36
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 30
- 239000013078 crystal Substances 0.000 claims description 30
- 238000003756 stirring Methods 0.000 claims description 30
- XNPMXMIWHVZGMJ-UHFFFAOYSA-N pyridine-2,6-dicarbonitrile Chemical compound N#CC1=CC=CC(C#N)=N1 XNPMXMIWHVZGMJ-UHFFFAOYSA-N 0.000 claims description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 28
- ITMCEJHCFYSIIV-UHFFFAOYSA-N triflic acid Chemical compound OS(=O)(=O)C(F)(F)F ITMCEJHCFYSIIV-UHFFFAOYSA-N 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 20
- 238000009210 therapy by ultrasound Methods 0.000 claims description 19
- 238000006731 degradation reaction Methods 0.000 claims description 18
- 238000000926 separation method Methods 0.000 claims description 17
- 230000008569 process Effects 0.000 claims description 16
- 238000001816 cooling Methods 0.000 claims description 15
- 239000008367 deionised water Substances 0.000 claims description 15
- 229910021641 deionized water Inorganic materials 0.000 claims description 15
- 239000003344 environmental pollutant Substances 0.000 claims description 15
- 239000004570 mortar (masonry) Substances 0.000 claims description 15
- 231100000719 pollutant Toxicity 0.000 claims description 15
- 230000015556 catabolic process Effects 0.000 claims description 14
- 125000003118 aryl group Chemical group 0.000 claims description 9
- 239000002351 wastewater Substances 0.000 claims description 8
- 238000011282 treatment Methods 0.000 claims description 7
- 230000003197 catalytic effect Effects 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 4
- 229910052736 halogen Inorganic materials 0.000 claims description 4
- 150000002367 halogens Chemical class 0.000 claims description 4
- 238000004128 high performance liquid chromatography Methods 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 4
- 239000012528 membrane Substances 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 238000005070 sampling Methods 0.000 claims description 4
- 238000002336 sorption--desorption measurement Methods 0.000 claims description 4
- 239000000356 contaminant Substances 0.000 claims description 3
- 239000012298 atmosphere Substances 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- 238000001179 sorption measurement Methods 0.000 abstract description 22
- JUJWROOIHBZHMG-UHFFFAOYSA-N pyridine Substances C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 abstract description 19
- 238000001035 drying Methods 0.000 abstract description 18
- 239000002243 precursor Substances 0.000 abstract description 16
- 239000011148 porous material Substances 0.000 abstract description 13
- JYEUMXHLPRZUAT-UHFFFAOYSA-N 1,2,3-triazine Chemical group C1=CN=NN=C1 JYEUMXHLPRZUAT-UHFFFAOYSA-N 0.000 abstract description 9
- 239000002957 persistent organic pollutant Substances 0.000 abstract description 8
- 238000006116 polymerization reaction Methods 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 4
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 abstract description 3
- 230000006798 recombination Effects 0.000 abstract description 3
- 238000005215 recombination Methods 0.000 abstract description 3
- 238000001308 synthesis method Methods 0.000 abstract description 3
- 238000002604 ultrasonography Methods 0.000 abstract description 3
- 238000001782 photodegradation Methods 0.000 abstract description 2
- 230000002035 prolonged effect Effects 0.000 abstract 1
- 230000000452 restraining effect Effects 0.000 abstract 1
- 239000000463 material Substances 0.000 description 44
- 239000010453 quartz Substances 0.000 description 37
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 37
- 239000007787 solid Substances 0.000 description 27
- 230000000052 comparative effect Effects 0.000 description 22
- 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 15
- 239000000126 substance Substances 0.000 description 15
- 239000012299 nitrogen atmosphere Substances 0.000 description 14
- 238000000227 grinding Methods 0.000 description 13
- 239000005457 ice water Substances 0.000 description 13
- 238000005406 washing Methods 0.000 description 13
- 230000000694 effects Effects 0.000 description 9
- 239000010410 layer Substances 0.000 description 9
- 238000007146 photocatalysis Methods 0.000 description 8
- 238000002474 experimental method Methods 0.000 description 6
- 239000011229 interlayer Substances 0.000 description 5
- 238000001000 micrograph Methods 0.000 description 4
- 239000011941 photocatalyst Substances 0.000 description 4
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 125000004093 cyano group Chemical group *C#N 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 229910017053 inorganic salt Inorganic materials 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- 238000009777 vacuum freeze-drying Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- MYOXMAQGEINAEF-UHFFFAOYSA-N [C].N1=NN=CC=C1 Chemical compound [C].N1=NN=CC=C1 MYOXMAQGEINAEF-UHFFFAOYSA-N 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-O diazynium Chemical group [NH+]#N IJGRMHOSHXDMSA-UHFFFAOYSA-O 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 230000004298 light response Effects 0.000 description 2
- 229910001507 metal halide Inorganic materials 0.000 description 2
- 150000005309 metal halides Chemical class 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000013033 photocatalytic degradation reaction Methods 0.000 description 2
- 238000013032 photocatalytic reaction Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000005829 trimerization reaction Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- CABMTIJINOIHOD-UHFFFAOYSA-N 2-[4-methyl-5-oxo-4-(propan-2-yl)-4,5-dihydro-1H-imidazol-2-yl]quinoline-3-carboxylic acid Chemical compound N1C(=O)C(C(C)C)(C)N=C1C1=NC2=CC=CC=C2C=C1C(O)=O CABMTIJINOIHOD-UHFFFAOYSA-N 0.000 description 1
- WJJMNDUMQPNECX-UHFFFAOYSA-N Dipicolinic acid Natural products OC(=O)C1=CC=CC(C(O)=O)=N1 WJJMNDUMQPNECX-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 150000001721 carbon Chemical class 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
Classifications
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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
-
- 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—
-
- 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
-
- 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
-
- 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
-
- 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
-
- 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 dinitrogen group embedded carbon nano-frame. Embedding two nitrogen-containing groups by adopting a structure regulation strategy: the pore diameter and the specific surface area of the carbon nano-frame are changed by utilizing triazine group polymerization reaction of two precursors of 2, 6-pyridine dimethyl nitrile and terephthalonitrile with different molar mass ratios, and the adsorption performance of the carbon nano-frame is optimized by adopting ultrasonic to promote the offset widening of a sheet stacking structure and forming multiple pore channels; simultaneously, ultrasound and embedding pyridine groups into the carbon nano-frame are used for restraining recombination of electrons and holes, widening the photoresponse range, improving the photocatalytic activity of the carbon nano-frame, fully drying by adopting a freeze drying technology, and well maintaining an ultrasound optimized structure. The carbon nano-frame prepared by the method is low in price, the synthesis method is environment-friendly, the concentrated organic pollutants can be effectively enriched and photodegradation is carried out on the concentrated organic pollutants, the regeneration cycle of the carbon nano-frame is realized, the service cycle is effectively prolonged, and the cost is reduced.
Description
Technical Field
The invention belongs to the field of material preparation, and particularly relates to a preparation method and application of a dinitrogen group embedded carbon nano-frame.
Background
The adsorption method is widely applied as a mainstream method for removing organic pollutants in water, but the organic pollutants are not truly removed and even secondary pollution is caused, so that development of a material with adsorption capacity and capable of realizing photodegradation of the organic pollutants is a very development prospect, and the material has the advantage of realizing regeneration and recycling of the material. The emerging method is simple to operate, high in efficiency, environment-friendly and has universality for the treatment of polluted water bodies.
Carbon nano-frames with abundant porous structures and excellent physicochemical stability have recently been considered as a promising contaminant 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 channel structure, and is favorable for adsorbing organic pollutants. In addition, the carbon nano-frame has wider optical band gap, a certain light response range and great application potential in the field of photocatalysis. However, many photocatalysts with adsorption performance have a common problem at present that the mutual interference of adsorption sites and photocatalysis sites can generate negative effects, and the ideal effect is often not achieved, so that the regeneration performance of the material is reduced. In order to solve the problem, the adsorption capacity and the photocatalytic activity of the material are improved, the material is regenerated and recycled, and the structural regulation and control are an effective means.
Chinese patent No. cn202110532349.X discloses a process for the preparation of pyridine-enriched cationic covalent triazine polymers. The preparation method comprises calcining T-CN and anhydrous zinc chloride in a vacuum sealed container at high temperature (400 ℃ and 500 ℃) for 40 hours, wherein although the material prepared in the patent has triazine groups and pyridine groups, the preparation method still needs vacuum and high-temperature conditions, and certain potential safety hazard exists.
Disclosure of Invention
The invention aims to provide a preparation method and application of a dinitrogen group embedded carbon nano-frame.
In order to reduce the negative influence caused by mutual interference of adsorption sites and photocatalysis sites and improve adsorption capacity and photocatalytic activity, the invention adopts a brand new idea: the 2, 6-pyridine dinitrile and terephthalonitrile precursors are mixed according to a certain proportion to prepare the dinitrogen group embedded carbon nano-frame, wherein after the triazine groups formed by cyano groups of the two precursors undergo polymerization reaction, the structure and the aperture of the carbon nano-frame can be adjusted, the specific surface area is increased, the lamellar stacking structure generated by combining an ultrasonic means is offset to a certain extent, the interlayer vertical distance is widened, multiple pore channels are formed, the number of adsorption sites and the exposure probability are increased, and the adsorptivity of the carbon nano-frame can be optimized; secondly, the ultrasonic wave can shift the lamellar structure of the carbon nano-frame, the interlayer spacing is increased, the electron density of atoms in the molecular structure of the material is changed, and the hole distribution generated by light excitation is changed along with the interlayer spacing, so that the holes are not easy to be combined with electrons, and simultaneously, the pyridine group is embedded in the carbon nano-frame, thereby being beneficial to adsorbing pollutants, widening the light response range and improving the photocatalytic activity; and thirdly, compared with the conventional heating and drying method, the vacuum freeze drying method can effectively remove the impurities such as water and inorganic salt dissolved in the water on the surface and in the pores of the carbon nano-frame, the carbon nano-frame is frozen at the low temperature, the volume is hardly changed, the ultrasonic optimized sheet stacking structure is maintained in the original form, and the adsorption and photocatalysis performance of the material are not affected. Fourthly, the trifluoro methane sulfonic acid is used as a catalyst to synthesize the carbon nano-frame, thereby avoiding the waste of energy and potential safety hazards under the conditions of vacuum and high temperature, greatly shortening the preparation period of the material and achieving the purpose of saving the cost.
The technical scheme of the invention is as follows:
the preparation method of the dinitrogen group embedded carbon nano frame comprises the following steps:
1) Mixing 2, 6-pyridine dinitrile and terephthalonitrile, adding 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 yellowish liquid, then carrying out heating treatment, and cooling to obtain yellow crystals;
3) The yellow crystal is alternately washed by deionized water and acetone, is freeze-dried to constant weight after solid-liquid separation, and is ground by a mortar to obtain the dinitrogen group embedded carbon nano frame;
the steps are all completed under normal pressure, and the ratio of the amounts of the 2, 6-pyridine dimethyl nitrile and 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 to 5 ℃, preferably 0 ℃, so as to prevent a great amount of heat from being released when 2, 6-pyridine dinitrile and terephthalonitrile are dissolved in trifluoromethanesulfonic acid.
Further, in the step 1), the ratio of the total amount of 2, 6-pyridine dinitrile and terephthalonitrile substances to the volume amount of trifluoromethanesulfonic acid is controlled to be 1.0-2.0 mmol/mL, preferably 1.6mmol/mL, and trifluoromethanesulfonic acid is used as two precursors of 2, 6-pyridine dinitrile and terephthalonitrile to carry out trimerization reaction to synthesize the dinitrogen group embedded carbon nano frame, so that the material can be synthesized under mild conditions, and energy waste and potential safety hazard caused by a vacuum and high-temperature synthesis path are effectively avoided.
Further, in the process of stirring to form light yellow liquid in the step 1), stirring is carried out by using a constant-temperature water bath magnetic stirrer, and the rotating speed is controlled to be 600-1200 rpm, preferably 900rpm; the stirring time is controlled to be 1-3 h, preferably 2h, so that two precursors of 2, 6-pyridine dinitrile and terephthalonitrile can be fully dissolved in trifluoromethanesulfonic acid, and the subsequent trimerization reaction for synthesizing the carbon nano-frame can be smoothly carried out.
Further, in the ultrasonic treatment process of the step 2), the temperature is constantly controlled at 10-40 ℃, preferably 30 ℃; the ultrasonic frequency is 20-80 kHz, preferably 40kHz; the ultrasonic treatment time is 20-60 min, preferably 40min, the ultrasonic is taken as a key step of controlling the morphology structure of the dinitrogen group embedded carbon nano-frame, so that two precursors and trifluoromethanesulfonic acid can be well mixed uniformly, the material sheet layer stacking structure layer is promoted to deviate to a certain extent and the vertical distance is widened, and meanwhile, rich pore channels are generated, in addition, the electron density of atoms in the molecular structure of the material is changed, and the photo-generated hole distribution generated by photocatalysis is also changed; in the heating treatment process, the temperature is controlled to be 80-120 ℃, preferably 100 ℃; the constant temperature time is controlled to be 10-40 min, preferably 30min, and the precursor molecular bond is broken and recombined in the process, and the micromolecules are polymerized again into the dinitrogen group embedded carbon nano frame under the catalysis of the trifluoromethanesulfonic acid at high temperature.
Further, 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 10000rpm; the centrifugation time is controlled to be 3-8 min, preferably 5min.
Further, 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 hours, preferably 24 hours, the freeze drying is carried out under the vacuum condition, so that water on the surface and in pores of the material is changed into solid water and sublimated in a very short time, inorganic salt and other impurities dissolved in the water can be removed together, meanwhile, the volume of the carbon nano frame is almost unchanged in a frozen state, and the ultrasonic optimized lamellar stacked structure is maintained without influencing the adsorption and photocatalytic performance of the carbon nano frame.
The application of the dinitrogen group embedded carbon nano frame in adsorption-photo-regeneration catalytic degradation of aromatic pollutants in wastewater comprises the following steps:
1) Adding a dinitrogen group embedded carbon nano-frame into aromatic pollutant wastewater, magnetically stirring in a dark place for 60min to reach adsorption-desorption balance, then simulating sunlight conditions by using a metal halogen lamp (400W), magnetically stirring to perform photocatalytic pollutant degradation reaction, regularly sampling, filtering by using a filter membrane, and detecting the residual concentration of the aromatic pollutant by using high performance liquid chromatography;
2) And (3) collecting the reacted di-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 1 st round of regeneration of the di-nitrogen group embedded carbon nano-frame, and the number of regeneration rounds is the same.
Further, the aromatic pollutant is bisphenol A or naphthalene, and the concentration of the diaza group embedded carbon nano-frame in the wastewater is 10-30 mg/L, preferably 20mg/L.
The invention provides a mild synthesis method for carrying out structure regulation and control and embedding triazine groups and pyridine groups into two precursors, which prepares the dinitrogen group embedded carbon nano-frame by utilizing key steps such as ultrasonic treatment, freeze drying and the like, and has the following advantages in implementation and use:
1. compared with the common adsorbent, the dinitrogen group embedded carbon nano-frame pore structure is rich, the specific surface area is large, and the photocatalyst has photocatalytic activity and can effectively degrade organic pollutants; secondly, the dinitrogen group embedded carbon nano-frame adopts a structure regulation strategy, and the triazine and pyridine two groups embedded in the carbon nano-frame are beneficial to the transmission of photo-generated electrons, and pi-pi accumulation effect exists between the highly conjugated structure and organic pollutants in water, especially aromatic pollutants.
2. Compared with the traditional method for embedding the dinitrogen group, the synthesis method adopted by the dinitrogen group embedded carbon nano frame is mild, avoids energy waste and potential safety hazards caused by vacuum and high temperature conditions, greatly shortens the preparation period and is low in cost; meanwhile, the content of the dinitrogen groups can be controlled by changing the proportion of the precursor.
3. Compared with the common layered structure, the invention optimizes the structure of the material by combining the ultrasonic means, particularly realizes that the vertical distance between layers in the stacked structure of the layers is widened, and the layers are offset to a certain extent and form multiple pore channels, so that the quantity and the exposure probability of adsorption sites in the layers of the material 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, the recombination of electrons and photo-generated holes is restrained, the adsorption performance and the photocatalytic activity are improved, the recycling 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 and drying technology, the invention adopts the vacuum freeze-drying technology, sublimates water molecules in the pores on the surface and in the interior of the material at extremely low temperature in a short time, achieves the complete drying of the material, simultaneously removes inorganic salt and other impurities dissolved in the water, and causes the volume of the material to expand and damage the structural morphology to a certain extent.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) micrograph of a dinitrogen group embedded carbon nano-frame prepared in example 1;
FIG. 2 is a Scanning Electron Microscope (SEM) micrograph of a dinitrogen group embedded carbon nano-frame prepared in example 3;
FIG. 3 is a Scanning Electron Microscope (SEM) micrograph of a dinitrogen group embedded carbon nano-frame prepared in example 5;
fig. 4 is a transmission electron microscope image of the dinitrogen group embedded carbon nano frame prepared in example 3.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples so that those skilled in the art can better understand the spirit of the present invention, but the scope of the present invention is not limited thereto.
Process of embedding a dinitrogen group in a carbon nano-frame: 2, 6-pyridine dimethyl nitrile and terephthalonitrile are mixed according to a certain proportion, and then added into a certain volume of trifluoromethanesulfonic acid under the protection of nitrogen atmosphere at 0 ℃ to form a viscous and uniform solution through uniform stirring by a magnetic stirrer. In each of the examples below, cleavage and recombination of precursor molecular bonds was achieved using this method. Of course, those skilled in the art will recognize that the process of embedding the dinitrogen groups in the carbon nano frame is only a preferred mode of the present invention, and that each parameter may be adjusted according to actual needs. The 2, 6-pyridine-dinitrile and terephthalonitrile in the precursor can also be replaced, and other compounds with cyano groups and pyridine groups can be selected.
The optimization of the lamellar stacking structure of the dinitrogen group embedded carbon nano frame is promoted by ultrasonic steps, and the lamellar stacking structure is particularly characterized in that a certain degree of offset occurs between lamellar layers, so that the interlayer vertical distance is widened, and multiple pore channels are formed in the lamellar stacking structure.
The polymerization process of the dinitrogen group embedded carbon nano-frame is carried out by keeping constant temperature for a certain time after heating in an electrothermal blowing constant temperature drying oven, and the dinitrogen group embedded carbon nano-frame is polymerized again through small molecules under the catalysis of trifluoromethanesulfonic acid at high temperature.
Specific examples are as follows:
example 1
In this embodiment, the specific steps for preparing the di-nitrogen group embedded carbon nano-frame are as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.3443 g,2.67 mmol) and terephthalonitrile (0.6834 g,5.33 mmol) were put into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Example 2
In this embodiment, the specific steps for preparing the di-nitrogen group embedded carbon nano-frame are as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.4132 g,3.2 mmol) and terephthalonitrile (0.6150 g,4.8 mmol) were put into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Example 3
In this embodiment, the specific steps for preparing the di-nitrogen group embedded carbon nano-frame are as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Example 4
In this embodiment, the specific steps for preparing the di-nitrogen group embedded carbon nano-frame are as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.6198 g,4.8 mmol) and terephthalonitrile (0.4100 g,3.2 mmol) were put into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Example 5
In this example, the specific procedure for preparing the pyridine modified renewable triazine carbon based photocatalyst is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.6886 g,5.33 mmol) and terephthalonitrile (0.3417 g,2.67 mmol) were put into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Example 6
In this embodiment, the specific steps for preparing the di-nitrogen group embedded carbon nano-frame are as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.7747 g,6.0 mmol) and terephthalonitrile (0.2563 g,2.0 mmol) were put into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
In examples 1 to 6, the total amount of 2, 6-pyridine dinitrile and terephthalonitrile was controlled to 8mmol, and the structure of the carbon nano-frame was controlled by changing the ratio of the two materials. The carbon nano-frames obtained in examples 1, 3 and 5 were subjected to electron microscopic scanning, and the results were as described in fig. 1, 2 and 3. From the figure, the triazine groups and the pyridine groups are embedded into the carbon nano-frame, so that more pore channels are generated in the sheet stacking structure, the specific surface area of the material is increased, and the adsorption and photocatalysis performances of the material are improved. The excessive amount of pyridine groups may cause a part of pyridine not to be embedded into the carbon nano-frame structure, but to be accumulated on the surface of the carbon nano-frame to break up a part of the sheet stacking structure, and may also block light from reaching the carbon nano-frame. By carrying out transmission electron microscope scanning on the embodiment 3, the material well forms a sheet layer stacking structure, ultrasonic treatment promotes the deviation of sheets and the widening of the vertical distance between layers, exposure of adsorption sites and photocatalysis sites is facilitated, and the vacuum freeze drying technology well maintains the structural morphology of the material after ultrasonic optimization.
In example 3, the sum of the amounts of 2, 6-pyridine-dicarboxylic acid and terephthalonitrile was controlled to 8mmol, the ratio of the amounts of both materials was 1:1, and the conditions of ultrasonic and freeze-drying in example 3 were changed to prepare a series of carbon nano-frames.
The specific comparative examples are as follows:
comparative example 1
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm to form uniform light yellow liquid;
(3) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(6) And placing the separated solid in an oven, continuously maintaining at 60 ℃ for 24 hours, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 2
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And placing the separated solid in an oven, continuously maintaining at 60 ℃ for 24 hours, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 3
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm to form uniform light yellow liquid;
(3) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(6) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 4
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 20kHz, and carrying out ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 5
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of 75 ℃ below zero, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 6
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of-70 ℃, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Comparative example 7
In this comparative example, the specific procedure for preparing the di-nitrogen group embedded carbon nano-frame is as follows:
(1) 2, 6-Pyridinedicarbonitrile (0.5165 g,4.0 mmol) and terephthalonitrile (0.5125 g,4.0 mmol) were added into a quartz tube equipped with a rotor, and stirred magnetically and mixed well;
(2) Slowly adding 5.0mL of trifluoromethanesulfonic acid into a quartz tube under the protection of ice water bath and nitrogen atmosphere at the temperature of 0 ℃ and stirring for 2 hours at the rotating speed of 900rpm 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 performing ultrasonic treatment for 40min;
(4) Transferring to an electrothermal constant temperature blast drying oven, heating to 100deg.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 utilizing a centrifugal machine, the rotating speed is 10000rpm, and the centrifugal time is 5min;
(7) And then placing the separated solid into a vacuum freeze dryer, freeze drying for 24 hours at the temperature of minus 80 ℃, and grinding the dried solid substance by a mortar to obtain the dinitrogen group embedded carbon nano frame.
Application example 1
The dinitrogen group embedded carbon nano frames prepared by using examples 1 to 6 and comparative examples 1 to 7 respectively carry out adsorption-photo-regeneration catalytic degradation experiments on bisphenol A (BPA) under the irradiation of a metal halogen lamp, and the experimental steps are as follows: (1) Each group of experiments respectively adding 20mg of the dinitrogen group embedded carbon nano frame prepared in the examples 1-6 into 100mL of wastewater with bisphenol A (BPA) concentration of 100ppm, magnetically stirring in a dark place for 60min to reach adsorption-desorption balance, then simulating sunlight conditions by using a metal halogen lamp (400W), magnetically stirring to perform photocatalytic degradation pollutant reaction, regularly sampling, filtering with a 0.45 mu m filter membrane, and detecting the residual concentration of the BPA by using high performance liquid chromatography; (2) And (3) collecting the reacted dinitrogen group embedded carbon nano frame, freeze-drying the carbon nano frame (-75 ℃ for 24 hours) to constant weight, and repeating the experimental process of the step (1).
Wherein, the step (1) is 1 st round of regeneration of the carbon nano-frame embedded with the diazonium group, and the number of regeneration rounds is the same.
Application example 2
The dinitrogen group embedded carbon nano frames prepared by using examples 1 to 6 and comparative examples 1 to 7 respectively carry out adsorption-photo-regeneration catalytic degradation experiments on Naphthalene (NAP) under the irradiation of a metal halide lamp, and the experimental steps are as follows: (1) Each experiment was performed by adding 20mg of the pyridine-modified renewable triazine carbon-based photocatalyst prepared in examples 1 to 6 to 100mL of wastewater having Naphthalene (NAP) concentration of 100ppm, magnetically stirring in the dark for 60min to reach adsorption-desorption equilibrium, then simulating the sunlight condition with a metal halide lamp (400W), magnetically stirring to perform photocatalytic degradation of pollutants, periodically sampling, filtering with a 0.45 μm filter membrane, and detecting the residual concentration of NAP with high performance liquid chromatography; (2) And (3) collecting the reacted dinitrogen group embedded carbon nano frame, freeze-drying the carbon nano frame (-75 ℃ for 24 hours) to constant weight, and repeating the experimental process of the step (1).
Wherein, the step (1) is 1 st round of regeneration of the carbon nano-frame embedded with the diazonium group, and the number of regeneration rounds is the same. 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, and in the invention, the regeneration rate is an important index for measuring the adsorption and photo-regeneration catalytic performance of the material, and the first round of regeneration rate is 100%.
The results after the photocatalytic reaction for 6 hours are shown in tables 1 to 3, wherein table 1 shows the degradation rate of the dinitrogen group embedded carbon nano frame prepared in examples 1 to 6 on the first round of regeneration experiments of bisphenol a (BPA) and Naphthalene (NAP), the degradation effect of all the examples on two pollutants reaches more than 90%, and the degradation effect of example 3 on the two pollutants is the best, especially the degradation rate of the nano frame on NAP is as high as 95.6%. The double nitrogen group embedded carbon nano-frame synthesized by two precursors (2, 6-pyridine dinitrile and terephthalonitrile) with different molar mass ratios is subjected to multi-round regeneration after absorbing and degrading BPA and NAP, and has high regeneration rate, wherein each round of the double nitrogen group embedded carbon nano-frame has the highest regeneration rate after absorbing and degrading NAP. In example 3, when the ratio of the amounts of 2, 6-pyridine di-carbonitrile and terephthalonitrile materials was 1:1, the synthesized dinitrogen group embedded carbon nano-frame had the highest regeneration rates, the regeneration rates of the 2 nd to 4 th rounds of adsorption-degradation BPA were 98.1%, 97.1% and 95.0%, respectively, and the regeneration rates of the 2 nd to 4 th rounds of adsorption-degradation NAP were 98.9%, 98.4% and 95.1%, respectively. It can be seen that the di-nitrogen group embedded carbon nano-frame can adjust the regeneration rate by adjusting the ratio of the amounts of two precursor (2, 6-pyridine dinitrile and terephthalonitrile) substances.
TABLE 1 degradation Rate (%)
| Contaminants (S) | 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 24 wheel regeneration Rate (%)
| Number of regeneration wheels | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 |
| Wheel 1 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
| Wheel 2 | 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 |
| Wheel 4 | 90.5 | 92.0 | 95.0 | 90.3 | 89.5 | 88.2 |
TABLE 34 regeneration Rate of NAP degradation by irradiation of carbon nano-frame with embedded dinitrogen groups at different molar ratios for 6h (%)
| Number of regeneration wheels | Example 1 | Example 2 | Example 3 | Example 4 | Example 5 | Example 6 |
| Wheel 1 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 | 100.0 |
| Wheel 2 | 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 |
| Wheel 4 | 89.3 | 90.1 | 95.1 | 94.3 | 92.7 | 90.9 |
The results after the photocatalytic reaction for 6 hours are shown in tables 4 to 6. Wherein table 4 shows the degradation rate of the dinitrogen group embedded carbon nano-frame prepared in example 3 and comparative examples 1-7 on the first round of regeneration experiments of bisphenol a (BPA) and Naphthalene (NAP), and it can be seen that both ultrasonic and freeze drying treatments have a certain influence on the adsorption degradation performance of the carbon nano-frame, and the importance of the two steps in material structure optimization and maintenance is also verified. As can be seen from tables 5 and 6, the modification of the conditions of ultrasonic and freeze-drying in example 3 resulted in the multiple regeneration of bisphenol A (BPA) and Naphthalene (NAP) by adsorption and degradation of the synthesized di-nitrogen-group-embedded carbon nano-frame, and compared with the carbon nano-frame synthesized in example 3, it was found that neither the ultrasonic nor the freeze-drying had a great influence on the adsorption and photocatalytic properties of the material, so that the regeneration rate was significantly reduced. From the results of comparative examples 1 and 2, it can be seen that ultrasound is a key step in optimizing the carbon nano-framework structure and is also a precondition for maintaining the morphology and structure of the material by subsequent freeze-drying. Comparing comparative example 1 with comparative example 3, it was found that freeze-drying is a key step in maintaining the structural morphology of the material, and has a large influence on the regeneration rate. From the regeneration rate results of comparative examples 4 to 7, it can be found that reducing or increasing the ultrasonic frequency causes a certain reduction in the regeneration rate, wherein the reduction in the frequency causes insufficient ultrasonic energy to prevent the material structure from being better optimized, and the increase in the frequency causes the offset degree of the lamellar structure to be too large, so that the interlayer distance is too far to affect the photocatalytic performance; in addition, the influence of the temperature change of freeze drying on the adsorption and photocatalysis performance of the material is far smaller than that of the ultrasonic frequency change, when the temperature is higher, water molecules in pores deeper in the material can not be removed better, and when the temperature is lower, the electronic activity of the material can be reduced.
TABLE 4 degradation Rate (%)
TABLE 5 4 wheel regeneration Rate (%)
TABLE 6 4-round regeneration Rate (%)
The examples given above are only preferred embodiments of the present invention and are not intended to limit the present invention. For example, the precursors used in the preparation method of the material in the above examples are two of 2, 6-pyridine-dinitrile and terephthalonitrile, but it is not necessarily meant to adopt these two precursors, 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, so that the effects of the present invention can be achieved. For example, in the above embodiment, nitrogen is selected as the inert gas shielding gas, but it does not mean that nitrogen must be selected to realize the shielding effect, and only inert gas capable of avoiding oxidation of the raw material during the reduction reaction is selected, the material can be successfully synthesized and the effect of the invention can be realized.
It will thus be seen that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, all the technical schemes obtained by adopting the equivalent substitution or equivalent transformation are within the protection scope of the invention.
Claims (9)
1. The preparation method of the dinitrogen group embedded carbon nano frame is characterized by comprising the following steps of:
1) Mixing 2, 6-pyridine dinitrile and terephthalonitrile, adding 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 yellowish liquid, then carrying out heating treatment, and cooling to obtain yellow crystals;
3) The yellow crystal is alternately washed by deionized water and acetone, is freeze-dried to constant weight after solid-liquid separation, and is ground by a mortar to obtain the dinitrogen group embedded carbon nano frame;
the ratio of the amounts of the 2, 6-pyridine dinitrile and the terephthalonitrile is controlled to be 0.5-3:1;
in the ultrasonic treatment process of the step 2), the temperature is constantly controlled at 10-40 ℃; the ultrasonic frequency is 20-80 kHz; the ultrasonic treatment time is 20-60 min; in the heating treatment process, the temperature is controlled to be 80-120 ℃; the constant temperature time is controlled to be 10-40 min.
2. The method for preparing the dinitrogen 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 between-5 ℃ and 5 ℃.
3. The method for preparing a dinitrogen group embedded carbon nano-frame according to claim 1, wherein the ratio of the total amount of 2, 6-pyridine dinitrile and terephthalonitrile to the volume amount of trifluoromethanesulfonic acid in the step 1) is controlled to be 1.0-2.0 mmol/mL.
4. The method for preparing the dinitrogen group embedded carbon nano frame according to claim 1, wherein in the process of stirring to form light yellow liquid in step 1), a constant-temperature water bath magnetic stirrer is used for stirring, and the rotating speed is controlled to be 600-1200 rpm; the stirring time is controlled to be 1-3 h.
5. The method for preparing the dinitrogen 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 rotating speed is controlled to be 8000-12000 rpm; the centrifugation time is controlled to be 3-8 min.
6. The method for preparing the dinitrogen group embedded carbon nano frame according to 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 ℃; the freeze drying time is controlled to be 20-30 h.
7. The use of the di-nitrogen group embedded carbon nano-frame according to claim 1 for adsorption-photo-regeneration catalytic degradation of aromatic pollutants in wastewater, comprising the steps of:
1) Adding a dinitrogen group embedded carbon nano-frame into aromatic pollutant wastewater, magnetically stirring in a dark place for 60min to reach adsorption-desorption balance, then simulating sunlight conditions by using a 400W metal halogen lamp, magnetically stirring to perform photocatalytic pollutant degradation reaction, regularly sampling, filtering by using a filter membrane, and detecting the residual concentration of the aromatic pollutant by using high performance liquid chromatography;
2) And (3) collecting the reacted di-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 1 st round of regeneration of the di-nitrogen group embedded carbon nano-frame, and the number of regeneration rounds is the same.
8. The use according to claim 7, wherein the aromatic contaminant is bisphenol a or naphthalene.
9. The use according to claim 7, wherein the concentration of the di-nitrogen group embedded carbon nano-frame in the wastewater is 10-30 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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