Fe-doped graphite carbon nitride material with N defects as well as preparation method and application of Fe-doped graphite carbon nitride material

Abstract

The invention discloses a Fe-doped graphite carbon nitride material with N defects and a preparation method and application thereof.The preparation method comprises the steps that iron nitrate nonahydrate and 8-hydroxyquinoline are heated under the water bath condition, after the pH value is adjusted, an ink-color iron ligand can be separated out, then the iron ligand and melamine are mixed and calcined in air, and the Fe-doped graphite carbon nitride material with the N defects is obtained; and the gray black powder material CN-Q-Fe can be obtained. The material shows great potential in the aspect of treating water environment antibiotic pollution, and has excellent photocatalytic degradation performance on 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, and a preparation method and application thereof. Background Art

[0002] As people's living standards improve, new pollutant antibiotics have posed a health threat to people for decades due to their potential toxicity and persistence in the environment. Tetracycline antibiotics, in particular, 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. This technology can effectively remove tetracycline antibiotics from water through photocatalysts. Graphitic carbon nitride (g-C3N4) has a tunable electronic structure, is environmentally friendly, and has excellent physical and chemical property stability. However, the photogenerated carrier recombination rate of original graphitic carbon nitride is fast and its photoactivity is low. We still need to find a better way to solve this problem. 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 presence of chlortetracycline were 99.2%, 86.7% and 90.3% respectively, which showed that the tetracycline antibiotics could be efficiently degraded in multiple cycles and had a good degradation effect on tetracycline antibiotics in different water matrices.

[0005] The Fe-doped graphite carbon nitride material with N defects of the present invention can photocatalytically efficiently degrade tetracycline antibiotic solutions, has excellent cyclic degradation stability, and has a good degradation effect on tetracycline antibiotics in different water matrices. The invention can treat tetracycline antibiotic pollution in the water environment under a photocatalytic system, and shows great application potential in the field of water environment treatment.

[0006] To achieve the above object, the present invention provides the following technical solutions: The present invention provides a Fe-doped graphite carbon nitride material with N defects, wherein the graphite carbon nitride material can photocatalytically degrade tetracycline antibiotic solution, and within 30 minutes, 5 mg·L -1 Tetracycline hydrochloride solution, 10 mg·L -1 of oxytetracycline solution and 10 mg·L-1 The degradation rates of chloramphenicol solution reached 99.2%, 86.7% and 90.3% respectively. It can efficiently degrade tetracycline antibiotics in multiple cycles and has a good degradation effect on tetracycline antibiotics in different water matrices.

[0007] 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 graphite carbon nitride material with N defects.

[0008] Further, the following steps are included: 0.81 g of ferric nitrate nonahydrate and 0.87 g of 8-hydroxyquinoline were added to 40 ml of ethanol, and the mixture was ultrasonically dissolved and stirred continuously for 3 h in a water bath at 60 °C. 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 a precipitate. The inky solid material obtained after washing, 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, i.e., the Fe-doped graphite carbon nitride material with N defects.

[0009] The present invention also provides application of the above-mentioned Fe-doped graphite carbon nitride material with N defects in the field of photocatalysis.

[0010] Compared with the prior art, the present invention has the following beneficial effects: (1) The Fe-doped graphitic carbon nitride material (CN-Q-Fe) with N defects prepared in the present invention can be recycled to achieve a stable and efficient photocatalytic degradation effect of tetracycline antibiotics.

[0011] (2) The Fe-doped graphite carbon nitride material (CN-Q-Fe) with N defects 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

[0012] Figure 1 is the XRD pattern of the original graphite phase carbon nitride CN and CN-Q-Fe in Example 1; Figure 2 This is a comparison of the degradation effects of the prepared CN-Q-Fe and the original graphite phase carbon nitride (CN) on tetracycline hydrochloride (TC) under simulated sunlight; Figure 3 This is a comparison of the degradation effects of the prepared CN-Q-Fe and the original graphite phase carbon nitride (CN) on oxytetracycline (OTC) under simulated sunlight; Figure 4 This is a comparison of the degradation effects of the prepared CN-Q-Fe and the original graphite phase carbon nitride (CN) on chlortetracycline (CTC) under simulated sunlight; Figure 5 This is the cyclic degradation diagram of tetracycline hydrochloride (TC) by the prepared CN-Q-Fe under simulated sunlight irradiation; Figure 6 This is the cyclic degradation diagram of oxytetracycline (OTC) by the prepared CN-Q-Fe under simulated sunlight irradiation; Figure 7 This is the cyclic degradation diagram of chlortetracycline (CTC) by the prepared CN-Q-Fe under simulated sunlight irradiation; Figure 8 This is a comparison chart of the degradation effect of the prepared CN-Q-Fe on tetracycline hydrochloride (TC) in different water matrices under simulated sunlight; Fig. 9 This is a comparison chart of the degradation effect of the prepared CN-Q-Fe on oxytetracycline (OTC) in different water matrices under simulated sunlight; Fig.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; Fig.11 It is the electron paramagnetic resonance image of the original graphite phase carbon nitride CN and CN-Q-Fe in Example 1. DETAILED DESCRIPTION

[0013] The present invention is described in detail below with reference to specific embodiments and accompanying drawings.

[0014] The preparation method of the original 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 original graphite phase carbon nitride CN. Example 1

[0015] Preparation of Fe-doped graphitic carbon nitride material with N defects (CN-Q-Fe) 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 the mixture was ultrasonically dissolved and stirred continuously for 3 h in a water bath at 60 °C. 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 precipitate. The inky solid material obtained after washing, 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, i.e., the Fe-doped graphite carbon nitride material with N defects.

[0016] Figure 1 The XRD patterns of the original graphite carbon nitride CN and CN-Q-Fe in Example 1. Two diffraction peaks were found at 12.9° and 27.4° for all samples, belonging to the (100) plane and (002) plane in g-C3N4, respectively, corresponding to the regular in-plane stacking and interlayer ordered stacking modes of the heptazine units. The intensity of the diffraction peak at 27.4° was significantly weakened after the iron ion modification, indicating that the modified material became thinner.

[0017] Example 2: Photocatalytic degradation of tetracycline antibiotics 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 the visible light source, and a dark reaction was performed for 30 min 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 to observe the cyclic degradation activity of the reused CN-Q-Fe on the tetracycline hydrochloride solution. 5 mg·L -1 The 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.

[0018] Figure 2 This 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%.

[0019] 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 oxytetracycline by CN-Q-Fe reaches 86.7%.

[0020] Figure 4 This is a comparison chart of the degradation effects of CN-Q-Fe and original 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%.

[0021] Figure 5 This is a cyclic degradation experiment of tetracycline hydrochloride by CN-Q-Fe under simulated sunlight. In the five cyclic degradations, the degradation rates of tetracycline hydrochloride were 99.2%, 98.6%, 97.8%, 97.1% and 95.9%, respectively. This shows that CN-Q-Fe has excellent cyclic degradation stability for tetracycline hydrochloride.

[0022] Figure 6 This is a cyclic degradation experiment of oxytetracycline by CN-Q-Fe under simulated sunlight irradiation. In the five cyclic degradations, the degradation rates of oxytetracycline were 86.7%, 84.9%, 83.9%, 83.1% and 82.9%, respectively. This shows that CN-Q-Fe has excellent cyclic degradation stability for oxytetracycline.

[0023] Figure 7 This is a cyclic degradation experiment of CN-Q-Fe on chlortetracycline under simulated sunlight. In the five cycles of degradation, the degradation rates of chlortetracycline were 90.3%, 89.5%, 89%, 88.4% and 87.9%, respectively. This shows that CN-Q-Fe has excellent cyclic degradation stability for chlortetracycline.

[0024] Example 3: Photocatalytic degradation of tetracycline antibiotics in different water matrices Take 20 mg of CN-Q-Fe from Example 1 and add it to 50 ml of 5 mg·L -1 The photocatalytic degradation activity of CN-Q-Fe on tetracycline hydrochloride solution in different water matrices was tested by HPLC. 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 towards oxytetracycline and chlortetracycline in different water matrices.

[0025] 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 to impurities in different water matrices.

[0026] Fig. 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, proving 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.

[0027] Fig.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, proving that CN-Q-Fe has excellent photocatalytic degradation ability of chlortetracycline in different water matrices and has good anti-interference ability to impurities in different water matrices.

[0028] Fig.11 : This is the electron paramagnetic resonance image of CN and CN-Q-Fe in Example 1, and the presence of N defects is confirmed by electron paramagnetic resonance. 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. A Fe-doped graphite carbon nitride material having N defects, characterized in that: The graphite carbon nitride material can photocatalytically degrade tetracycline antibiotic solution, and 5 mg·L -1 Tetracycline hydrochloride solution, 10 mg·L -1 of oxytetracycline solution and 10 mg·L -1 The degradation rates of chloramphenicol solution 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.

2. The method for preparing a Fe-doped graphite carbon nitride material having N defects according to claim 1, characterized in that: The 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 graphite carbon nitride material with N defects.

3. The method for preparing a Fe-doped graphite carbon nitride material having N defects according to claim 2, characterized in that: The following steps are involved: 0.81 g of ferric nitrate nonahydrate and 0.87 g of 8-hydroxyquinoline were added to 40 ml of ethanol, and the mixture was ultrasonically dissolved and stirred continuously for 3 h in a water bath at 60 °C. 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 a precipitate. The inky solid material obtained after washing, 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, i.e., the Fe-doped graphite carbon nitride material with N defects.

4. Application of the Fe-doped graphite carbon nitride material with N defects as claimed in claim 1 in the field of photocatalysis.

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