A Fe-doped graphite carbon nitride material with N defects and its preparation method and application

Abstract

This invention discloses an Fe-doped graphitic carbon nitride material with nitrogen defects, its preparation method, and application. Iron nitrate nonahydrate and 8-hydroxyquinoline are heated in a water bath, and after adjusting the pH, an inky iron ligand is precipitated. The iron ligand is then mixed with melamine and calcined in air to obtain a gray-black powder material, CN-Q-Fe. This material has great potential for treating antibiotic contamination in aquatic environments, and exhibits excellent photocatalytic degradation of tetracycline antibiotics.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis, and in particular to an Fe-doped graphite carbon nitride material with N defects, a preparation method thereof, and applications thereof. Background Art

[0002] Tetracycline antibiotics can cause drug-resistant bacteria to appear in water bodies and are toxic to aquatic organisms.

[0003] Photocatalytic technology is a promising strategy for removing tetracycline antibiotics from water using photocatalysts. Graphitic carbon nitride (g-C3N4) has a tunable electronic structure, is environmentally friendly, and exhibits excellent physicochemical stability. However, pristine graphitic carbon nitride suffers from rapid recombination of photogenerated charge carriers and low photoactivity, necessitating the search for better solutions. Summary of the Invention

[0004] In order to overcome the problems existing in the prior art, the present invention prepared an iron (Fe)-doped g-C3N4 photocatalyst with nitrogen (N) defects, which could -1 Tetracycline hydrochloride (TC) solution, 10 mg·L -1 Oxytetracycline (OTC) solution and 10 mg·L -1 The degradation rates of chlortetracycline (CTC) solution in the water matrix reached 99.2%, 86.7% and 90.3% respectively, which can efficiently degrade tetracycline antibiotics in multiple cycles and has a good degradation effect on tetracycline antibiotics in different water matrices.

[0005] The Fe-doped graphitic carbon nitride material with nitrogen defects of the present invention can efficiently photocatalytically degrade tetracycline antibiotic solutions, exhibiting excellent cyclic degradation stability and good degradation effects on tetracycline antibiotics in various water matrices. This invention can be used to treat tetracycline antibiotic contamination in aquatic environments using a photocatalytic system, demonstrating significant potential for application in the field of water environment management.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a Fe-doped graphite carbon nitride material with N defects, which can photocatalytically degrade tetracycline antibiotic solution and degrade 5 mg·L tetracycline within 30 min. -1 Tetracycline hydrochloride solution, 10 mg·L -1 of oxytetracycline solution and 10 mg·L -1The degradation rates of chloramphenicol solution reached 99.2%, 86.7% and 90.3% respectively, which can efficiently degrade tetracycline antibiotics in multiple cycles and have good degradation effects on tetracycline antibiotics in different water matrices.

[0008] Furthermore, a mixture of ferric nitrate nonahydrate and 8-hydroxyquinoline is heated in a water bath, and after pH adjustment, an inky iron ligand is obtained. The iron ligand is mixed with melamine and then calcined in air to prepare the Fe-doped graphitic carbon nitride material with N defects.

[0009] Further, the following steps are included:

[0010] 0.81 g of ferric nitrate nonahydrate and 0.87 g of 8-hydroxyquinoline were added to 40 ml of ethanol, and after ultrasonic dissolution, stirring was continued in a water bath at 60 ° C for 3 h. After stirring, the mixture should be uniformly mixed. Then, the pH value was adjusted to 7 with 0.1 mol / L NaOH solution to precipitate. The inky solid material obtained after washing with water, filtration and vacuum drying was the iron ligand. Subsequently, 5 g of melamine and 75 mg of the iron ligand were ground and calcined at 500 ° C in air for 3 h to obtain a gray-black powder material CN-Q-Fe, that is, the Fe-doped graphitic carbon nitride material with N defects.

[0011] The present invention also provides application of the above-mentioned Fe-doped graphite carbon nitride material with N defects in the field of photocatalysis.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] (1) The Fe-doped graphitic carbon nitride material with N defects (CN-Q-Fe) prepared in the present invention can be recycled to achieve stable and efficient photocatalytic degradation of tetracycline antibiotics.

[0014] (2) The Fe-doped graphite carbon nitride material with N defects (CN-Q-Fe) prepared in the present invention can still have a high degradation rate for tetracycline antibiotics in a variety of water matrices. The impurities in different water matrices have little effect on the degradation effect. The CN-Q-Fe polymer has good anti-interference ability against anions, cations and organic impurities in different water matrices during photocatalytic degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the XRD pattern of the original graphite phase carbon nitride CN and CN-Q-Fe in Example 1;

[0016] Figure 2This is a comparison of the degradation effects of the prepared CN-Q-Fe and pristine graphite-phase carbon nitride (CN) on tetracycline hydrochloride (TC) under simulated sunlight;

[0017] Figure 3 This is a comparison of the degradation effects of the prepared CN-Q-Fe and pristine graphite-phase carbon nitride (CN) on oxytetracycline (OTC) under simulated sunlight;

[0018] Figure 4 This is a comparison of the degradation effects of the prepared CN-Q-Fe and pristine graphite-phase carbon nitride (CN) on chlortetracycline (CTC) under simulated sunlight irradiation;

[0019] Figure 5 This is the cyclic degradation diagram of tetracycline hydrochloride (TC) prepared by CN-Q-Fe under simulated sunlight irradiation;

[0020] Figure 6 This is the cyclic degradation diagram of oxytetracycline (OTC) by the prepared CN-Q-Fe under simulated sunlight irradiation;

[0021] Figure 7 This is the cyclic degradation diagram of chlortetracycline (CTC) prepared by CN-Q-Fe under simulated sunlight irradiation;

[0022] Figure 8 This is a comparison of the degradation effects of the prepared CN-Q-Fe on tetracycline hydrochloride (TC) in different water matrices under simulated sunlight;

[0023] Figure 9 This is a comparison of the degradation effects of the prepared CN-Q-Fe on oxytetracycline (OTC) in different water matrices under simulated sunlight;

[0024] Figure 10 This is a comparison of the degradation effects of the prepared CN-Q-Fe on chlortetracycline (CTC) in different water matrices under simulated sunlight;

[0025] Figure 11 1 is the electron paramagnetic resonance spectrum of the original graphite phase carbon nitride CN and CN-Q-Fe in Example 1. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0027] The preparation method of the pristine graphite-phase carbon nitride CN used in the examples is as follows: 10 g of melamine is calcined in air at 550° C. for 4 h to form pristine graphite-phase carbon nitride CN. Example 1

[0028] Preparation of Fe-doped graphitic carbon nitride with N defects (CN-Q-Fe)

[0029] Preparation of CN-Q-Fe: 0.81 g of ferric nitrate nonahydrate and 0.87 g of 8-hydroxyquinoline were added to 40 ml of ethanol, and after ultrasonic dissolution, stirring was continued in a water bath at 60°C for 3 h. After stirring, the mixture should be uniformly mixed. Then, the pH value was adjusted to 7 with 0.1 mol / L NaOH solution to precipitate. The inky solid material obtained after washing with water, filtration and vacuum drying was the iron ligand; then, 5 g of melamine and 75 mg of the iron ligand were ground evenly and calcined at 500°C in air for 3 h to obtain a gray-black powder material CN-Q-Fe, which is the Fe-doped graphitic carbon nitride material with N defects.

[0030] Figure 1 The XRD patterns of pristine graphite carbon nitride (CN) and CN-Q-Fe in Example 1 are shown. All samples exhibit two diffraction peaks at 12.9° and 27.4°, belonging to the (100) and (002) planes of g-C3N4, corresponding to the regular in-plane stacking and interlayer ordered stacking of heptazine units, respectively. The intensity of the 27.4° diffraction peak decreases significantly after iron ion modification, indicating a thinner material.

[0031] Example 2: Photocatalytic degradation of tetracycline antibiotics

[0032] Take 20 mg of CN-Q-Fe from Example 1 and add it to 50 ml of 5 mg·L -1 A 3W LED lamp was used to simulate visible light, and a dark reaction was performed for 30 minutes before illumination to achieve adsorption and desorption equilibrium. The degradation of tetracycline hydrochloride (TC) was analyzed by high performance liquid chromatography. Furthermore, the CN-Q-Fe in the system after the first run was saved, and the above operation was repeated in the second run to continue observing the cyclic degradation activity of the reused CN-Q-Fe on the tetracycline hydrochloride solution. 5 mg·L -1 tetracycline hydrochloride solution was replaced with 10 mg·L -1 Oxytetracycline (OTC) solution and 10 mg·L -1 The other conditions and operations remained unchanged to investigate the photocatalytic degradation and photocatalytic cyclic degradation of oxytetracycline and chlortetracycline by CN-Q-Fe.

[0033] Figure 2This is a comparison chart of the degradation effects of CN-Q-Fe and pristine graphite phase carbon nitride (CN) on tetracycline hydrochloride under simulated sunlight. It can be seen from the figure that in the presence of CN, the degradation rate of tetracycline hydrochloride after 30 minutes of illumination is only 59.3%, while the degradation rate of tetracycline hydrochloride by CN-Q-Fe reaches 99.2%.

[0034] Figure 3 This is a comparison chart of the degradation effects of CN-Q-Fe and original graphite phase carbon nitride (CN) on oxytetracycline under simulated sunlight. It can be seen from the figure that in the presence of CN, the degradation rate of oxytetracycline after 30 minutes of illumination is only 58.6%, while the degradation rate of CN-Q-Fe on oxytetracycline reaches 86.7%.

[0035] Figure 4 This is a comparison chart of the degradation effects of CN-Q-Fe and pristine graphite phase carbon nitride (CN) on chlortetracycline under simulated sunlight. It can be seen from the figure that in the presence of CN, the degradation rate of chlortetracycline after 30 minutes of illumination is only 60.5%, while the degradation rate of chlortetracycline by CN-Q-Fe reaches nearly 90.3%.

[0036] Figure 5 This study simulated the cyclic degradation of tetracycline hydrochloride by CN-Q-Fe under sunlight. Over five cycles, the degradation rates were 99.2%, 98.6%, 97.8%, 97.1%, and 95.9%, respectively. This demonstrates the excellent cyclic degradation stability of CN-Q-Fe for tetracycline hydrochloride.

[0037] Figure 6 This study simulated the cyclic degradation of oxytetracycline by CN-Q-Fe under sunlight. Over five cycles, the degradation rates were 86.7%, 84.9%, 83.9%, 83.1%, and 82.9%, respectively. This demonstrates the excellent cyclic degradation stability of CN-Q-Fe for oxytetracycline.

[0038] Figure 7 This study simulated the cyclic degradation of chlortetracycline by CN-Q-Fe under sunlight. Over five cycles, the degradation rates of chlortetracycline were 90.3%, 89.5%, 89%, 88.4%, and 87.9%, respectively. This demonstrates the excellent cyclic degradation stability of CN-Q-Fe for chlortetracycline.

[0039] Example 3: Photocatalytic degradation of tetracycline antibiotics in different water matrices

[0040] Take 20 mg of CN-Q-Fe from Example 1 and add it to 50 ml of 5 mg·L -1The photocatalytic degradation activity of CN-Q-Fe on tetracycline hydrochloride solution in different aqueous matrices was tested by high-performance liquid chromatography. 5 mg·L -1 of tetracycline hydrochloride was replaced with 10 mg·L -1 of oxytetracycline and 10 mg·L -1 The other conditions and operations remained unchanged to investigate the photocatalytic degradation activity of CN-Q-Fe on oxytetracycline and chlortetracycline in different water matrices.

[0041] Figure 8 This is a comparison chart of the degradation effect of CN-Q-Fe on tetracycline hydrochloride in different water matrices under simulated sunlight. It can be seen from the figure that the degradation rates of tetracycline hydrochloride in deionized water matrix, tap water matrix, Yellow River water matrix and seawater matrix after 30 minutes of illumination are 99.2%, 96.2%, 94.1% and 91.1%, respectively, proving that CN-Q-Fe has excellent photocatalytic degradation ability of tetracycline hydrochloride in different water matrices and has good anti-interference ability against impurities in different water matrices.

[0042] Figure 9 This is a comparison chart of the degradation effect of CN-Q-Fe on oxytetracycline in different water matrices under simulated sunlight. It can be seen from the figure that the degradation rates of oxytetracycline in deionized water matrix, tap water matrix, Yellow River water matrix and seawater matrix after 30 minutes of illumination are 86.7%, 83.6%, 81.7% and 78.3%, respectively, which proves that CN-Q-Fe has excellent photocatalytic degradation ability of oxytetracycline in different water matrices and has good anti-interference ability to impurities in different water matrices.

[0043] Figure 10 This is a comparison chart of the degradation effect of CN-Q-Fe on chlortetracycline in different water matrices under simulated sunlight. It can be seen from the figure that the degradation rates of chlortetracycline in deionized water matrix, tap water matrix, Yellow River water matrix and seawater matrix after 30 minutes of illumination are 90.3%, 88.1%, 86% and 83.1%, respectively, which proves that CN-Q-Fe has excellent photocatalytic degradation ability of chlortetracycline in different water matrices and has good anti-interference ability against impurities in different water matrices.

[0044] Figure 11The electron paramagnetic resonance images of CN and CN-Q-Fe in Example 1 demonstrate the presence of N defects. The presence of N defects indicates that more unpaired electrons can be generated under visible light irradiation, further accelerating the formation of photogenerated charges in photocatalysis, thereby improving the photocatalytic ability of CN-Q-Fe.

Claims

1. Application of Fe-doped graphitic carbon nitride material with N defects in photocatalytic degradation of tetracycline antibiotic solution, characterized in that: Graphitic carbon nitride material was heated to 5 mg·L -1 Tetracycline hydrochloride solution, 10 mg·L -1 of oxytetracycline solution and 10 mg·L -1 The degradation rates of the chloramphenicol solution reached 99.2%, 86.7% and 90.3% respectively, and the tetracycline antibiotics can be degraded in multiple cycles, and the degradation effect on tetracycline antibiotics is good in different water matrices; the preparation method of the Fe-doped graphitic carbon nitride material with N defects is as follows: 0.81 g of ferric nitrate nine hydrate and 0.87 g of 8-hydroxyquinoline are added to 40 ml of ethanol, and after ultrasonic dissolution, stirring is continued for 3 h in a water bath at 60 ° C. After stirring, the state should be determined to be uniformly mixed, and then the pH value is adjusted to 7 with 0.1 mol / L NaOH solution to precipitate. The inky solid material obtained after washing, filtration and vacuum drying is the iron ligand; then 5 g of melamine and 75 mg of the iron ligand are ground evenly, and calcined at 500 ° C in air for 3 h to finally obtain a gray-black powder material CN-Q-Fe, that is, the Fe-doped graphitic carbon nitride material with N defects.

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