Method for promoting photodegradation of azithromycin in water body and application thereof

Abstract

The application belongs to the technical field of wastewater degradation, and specifically discloses a method for promoting photodegradation of azithromycin in water and application; after manganese porphyrin is added into wastewater containing azithromycin, the concentration of manganese porphyrin in each liter of wastewater is ensured to be 50 mg / L-100 mg / L, and the azithromycin is subjected to photodegradation under visible light conditions; the reaction condition of the degradation is simple, the input cost is low, and no toxic substances are generated in the process of promoting photodegradation of azithromycin, and the method is environment-friendly and non-polluting.

Description

TECHNICAL FIELD

[0001] The application relates to a method for promoting photodegradation of azithromycin in water bodies and application, and belongs to the technical field of wastewater degradation. BACKGROUND

[0002] Azithromycin, as a kind of macrolide antibiotic, is commonly used in life and has a high detection rate in domestic sewage, and is often detected in natural water bodies in rivers and lakes. Azithromycin can change the normal physiological characteristics of organisms in soil and water bodies, and has a serious impact on the survival of organisms.

[0003] Antibiotics in freshwater environments can be naturally degraded through physical, chemical and biological effects. Biological transformation and photodegradation are the main ways of natural degradation of antibiotics. Photosensitizer, as a carrier or acceptor of light energy, can effectively improve the efficiency of antibiotic photodegradation under certain conditions. In the current research on the photodegradation of azithromycin wastewater, photosensitizers synthesized from silicon dioxide, bismuth tungstate and bismuth molybdate are used for reaction. Most of the photosensitizers used in the existing research need to be prepared, and the synthesis materials are complex. Some intermediate products also have certain toxicity, and do not have the characteristics of green and economy. Moreover, most of them need to be degraded under ultraviolet light. SUMMARY

[0004] The purpose of the present application is to overcome the shortcomings of the prior art, provide a method for promoting photodegradation of azithromycin in water bodies and application, and solve the problem that conventional wastewater treatment and purification technology cannot effectively remove azithromycin in wastewater.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0006] In a first aspect, the present application provides a method for promoting photodegradation of azithromycin in water bodies. Manganese porphyrin is added to wastewater containing azithromycin, and then photodegradation of azithromycin is carried out under visible light. The concentration of manganese porphyrin in each liter of wastewater is 50mg / L-100mg / L.

[0007] In combination with the first aspect, further, the method comprises adjusting the pH of the wastewater mixed with manganese porphyrin to 7-9, and improving the photodegradation efficiency of azithromycin in water bodies.

[0008] Further, the method comprises oxygenating the wastewater mixed with manganese porphyrin to ensure that the dissolved oxygen content in the wastewater is greater than 10, and promoting the activation of manganese porphyrin.

[0009] Further, the concentration of manganese porphyrin in each liter of wastewater is 50mg / L.

[0010] Further, the light intensity of the visible light is 3000lx-4000lx.

[0011] In a second aspect, the present application provides an application of the azithromycin photodegradation in water, using any of the above-mentioned methods for promoting the azithromycin photodegradation in water.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] The present application uses manganese porphyrin as a photosensitizer, and only needs to carry out the azithromycin photodegradation reaction under visible light, so that the reaction condition is simple, the manganese porphyrin can be reused, the input cost is low, and the manganese porphyrin does not produce toxic substances in the process of promoting the azithromycin photodegradation, is friendly to the environment, and has no pollution. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the influence of different dosages of manganese porphyrin provided by the embodiment of the present application on the azithromycin photodegradation efficiency in water;

[0015] Figure 2 is the influence of manganese porphyrin on the azithromycin photodegradation efficiency of different initial concentrations;

[0016] Figure 3 is the influence of manganese porphyrin on the azithromycin photodegradation efficiency in water under different visible light intensities;

[0017] Figure 4 is the influence of manganese porphyrin on the azithromycin photodegradation efficiency in water under different pH values;

[0018] Figure 5 is the influence of manganese porphyrin on the azithromycin photodegradation efficiency in water under different dissolved oxygen environments;

[0019] Figure 6 is the influence of manganese porphyrin on the azithromycin photodegradation efficiency in water under different concentrations of nitrate;

[0020] Figure 7 is the MS spectrum of the azithromycin degradation product provided by the embodiment of the present application;

[0021] Figure 8 is the chemical structure and degradation pathway of part of the azithromycin degradation product provided by the embodiment of the present application. DETAILED DESCRIPTION

[0022] The present application will be further described below in combination with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0023] The application provides a method for promoting the photodegradation of azithromycin in water, which comprises adding manganese porphyrin into azithromycin-containing wastewater and then performing photodegradation of azithromycin under visible light, wherein the concentration of manganese porphyrin in the wastewater is 50 mg / L-100 mg / L per liter of wastewater, and the illumination intensity of visible light is 3000 lx-4000 lx.

[0024] After 3h of reaction, the removal rate of azithromycin in the wastewater can reach 92.0-97.2%

[0025] The photodegradation effect of azithromycin can be further improved by the following operations:

[0026] The pH of the wastewater after mixing with manganese porphyrin is adjusted to 7-9;

[0027] The wastewater after mixing with manganese porphyrin is oxygenated to ensure that the dissolved oxygen content in the wastewater is greater than 10;

[0028] The application is further described in detail in combination with examples and comparative examples.

[0029] The application provides seven examples and one comparative example, and the examples and the comparative example use finished azithromycin solid to prepare a mother liquor with a mass concentration of 1 g / L (anhydrous ethanol: pure water = 1:1), dilute the mother liquor, and configure to obtain azithromycin solutions with concentrations of 10 mg / L, 20 mg / L, 40 mg / L, 80 mg / L and 100 mg / L.

[0030] Example 1

[0031] As shown in Table 1, the effects of different dosages of manganese porphyrin provided by the application on the photodegradation efficiency of azithromycin in water are as follows: Figure 1 Manganese porphyrin is added to 100 mg / L azithromycin solution to make the concentration of manganese porphyrin in the solution be 20 mg / L, 50 mg / L, 100 mg / L, 200 mg / L and 300 mg / L, respectively;

[0032] A small amount of hydrochloric acid and sodium hydroxide solution are used to make the pH of the solution be 7.0, and the solution is reacted under visible light; samples are taken every 30 minutes, and centrifugal separation, solid-phase extraction and color development experimental operations are performed, and then the absorbance is measured by using a visible spectrophotometer.

[0033] Under the conditions of this example, the results of the photodegradation of azithromycin within 3h are shown in Table 1:

[0034] Table 1: Photodegradation efficiency of azithromycin under different dosages of manganese porphyrin (%)

[0035]

[0036] Mn porphyrin 0 min 30 min 60 min 90 min 120 min 150 min 180 min 20 mg / L 0.00 24.84 56.19 65.89 73.35 78.57 82.31 50 mg / L 0.00 60.66 80.07 89.77 94.25 96.49 97.23 100 mg / L 0.00 50.22 76.34 83.80 89.02 92.75 94.99 200 mg / L 0.00 15.89 33.05 56.93 70.37 77.08 79.32 300 mg / L 0.00 18.13 29.32 48.72 58.43 63.65 65.89 ​

[0037] As can be seen from Table 1, the concentration of the manganese porphyrin in the wastewater is 50 mg / L-100 mg / L, and the effect of degrading azithromycin is optimal; preferably, when the concentration of the manganese porphyrin in the wastewater is 50 mg / L, the degradation efficiency of azithromycin after 3 h is 97.2%.

[0038] Example Two

[0039] 100 mL of 10 mg / L, 20 mg / L, 40 mg / L, 80 mg / L and 100 mg / L azithromycin solutions were respectively prepared, 5 mg of manganese porphyrin was added, a small amount of hydrochloric acid and sodium hydroxide solution was used to make the pH of the solution 7.0, and the reaction was carried out under visible light, and the sample was taken every 30 minutes, and the centrifugal separation, solid phase extraction and color development experimental operations were carried out, and then the absorbance was measured using a visible spectrophotometer.

[0040] Under the conditions of this example, the results of the photodegradation reaction of azithromycin within 3 h are shown in Table 2:

[0041] Table 2: Photodegradation efficiency (%) of azithromycin with different initial concentrations after adding manganese porphyrin

[0042] Azithromycin 0 min 30 min 60 min 90 min 120 min 150 min 180 min 10 mg / L 0.00 49.93 64.85 79.78 79.78 79.78 79.78 20 mg / L 0.00 52.57 67.50 74.96 82.43 89.89 89.89 40 mg / L 0.00 38.97 53.90 65.09 72.56 78.15 81.88 80 mg / L 0.00 62.02 79.75 86.28 91.88 94.67 96.54 100 mg / L 0.00 60.66 80.07 89.77 94.25 96.49 97.23

[0043] As can be seen from Table 2, after adding manganese porphyrin, the degradation efficiency of 100 mg / L azithromycin solution after 3 h is 97.2%.

[0044] Example Three

[0045] 100 mL of 100 mg / L azithromycin solution was prepared, 5 mg of manganese porphyrin was added, a small amount of hydrochloric acid and sodium hydroxide solution was used to make the pH of the solution 7.0, and the reaction was carried out under visible light intensity of 2000 lx, 3000 lx and 4000 lx, respectively, and the sample was taken every 30 minutes, and the centrifugal separation, solid phase extraction and color development experimental operations were carried out, and then the absorbance was measured using a visible spectrophotometer.

[0046] Under the conditions of this example, the results of the photodegradation reaction of azithromycin within 3 h are shown in Table 3:

[0047] Table 3: Photodegradation efficiency (%) of azithromycin under different visible light intensities after adding manganese porphyrin

[0048] Light intensity 0 min 30 min 60 min 90 min 120 min 150 min 180 min 2000lx 0.00 52.46 71.11 80.07 86.04 89.77 92.75 3000lx 0.00 60.66 80.07 89.77 94.25 96.49 97.23 4000lx 0.00 65.89 80.81 89.02 93.50 95.74 97.23

[0049] As can be seen from Table 3, when the visible light intensity is in the range of 3000 lx-4000 lx, the effect is more optimal after adding manganese porphyrin, and the degradation efficiency of azithromycin after 3 h can reach 97.2%.

[0050] Example Four

[0051] Prepare 100 mL of 100 mg / L azithromycin solution. Add 5 mg of manganese porphyrin to 100 mL of the solution. Use a small amount of hydrochloric acid and sodium hydroxide solution to adjust the pH of the mixed solution to 3.0, 5.0, 7.0, 9.0, and 11.0, respectively. React under visible light. Take samples every 30 minutes and perform centrifugation, solid-phase extraction, and color development. Measure the absorbance using a visible light spectrophotometer.

[0052] Under the conditions of this embodiment, the results of the photodegradation reaction of azithromycin within 3 hours are shown in Table 4:

[0053] Table 4: Photodegradation efficiency (%) of azithromycin at different pH values ​​after the addition of manganese porphyrin

[0054] pH 0 min 30 min 60 min 90 min 120 min 150 min 180 min pH = 3 0.00 41.26 66.63 80.81 88.28 91.26 93.50 pH = 5 0.00 51.71 74.10 84.54 90.51 94.25 95.74 pH = 7 0.00 60.66 80.07 89.77 94.25 96.49 97.23 pH = 9 0.00 65.14 83.05 91.26 94.99 97.23 97.98 pH = 11 0.00 56.19 76.34 86.04 91.26 94.99 95.74

[0055] As can be seen from Table 4, adjusting the pH to 7-9 resulted in better time performance; preferably, when pH=9.0, the addition of manganese porphyrin resulted in a degradation efficiency of 97.9% for azithromycin after 3 hours.

[0056] Example 5

[0057] Prepare 100 mL of 100 mg / L azithromycin solution, add 5 mg of manganese porphyrin, and adjust the pH of the solution to 7.0 with a small amount of hydrochloric acid and sodium hydroxide solution. Use a pump to blow air in and measure the dissolved oxygen content of the solution to be 6.71, 9.35 and 10.73 respectively. React under visible light, take samples every 30 minutes, and perform centrifugation, solid phase extraction and color development. Then use a visible light spectrophotometer to measure the absorbance.

[0058] Under the conditions of this embodiment, the results of the photodegradation reaction of azithromycin within 3 hours are shown in Table 5:

[0059] Table 5: Photodegradation efficiency (%) of azithromycin under different dissolved oxygen conditions after the addition of manganese porphyrin

[0060] Dissolved oxygen 0 min 30 min 60 min 90 min 120 min 150 min 180 min DO = 6.71 0.00 60.66 80.07 89.77 94.25 96.49 97.23 DO = 9.35 0.00 62.90 80.81 90.51 94.99 97.23 97.98 DO = 10.73 0.00 72.60 86.78 93.50 96.49 97.98 99.00

[0061] As can be seen from Table 5, when DO = 10.73, the degradation efficiency of azithromycin was 97.9% after 150 min with the addition of manganese porphyrin. Therefore, the present invention preferably uses wastewater with a dissolved oxygen content greater than 10.

[0062] Example 6

[0063] A 100 mg / L azithromycin solution of 100 mL was prepared, and sodium nitrate solution was added to make the concentration of nitrate 0 mg / L, 100 mg / L, 200 mg / L, 300 mg / L, and 400 mg / L, respectively. Then 5 mg of manganese porphyrin was added. A small amount of hydrochloric acid and sodium hydroxide solution was used to adjust the pH of the solution to 7.0. The solution was reacted under visible light. Samples were taken every 30 minutes, and centrifugal separation, solid-phase extraction, and color development were performed. The absorbance was measured using a visible spectrophotometer.

[0064] Under the conditions of this example, the results of the photodegradation of azithromycin within 3 h are shown in Table 6.

[0065] Table 6: Photodegradation efficiency of azithromycin under different concentrations of nitrate after adding manganese porphyrin (%)

[0066] Nitrate 0 min 30 min 60 min 90 min 120 min 150 min 180 min 0 0.00 60.66 80.07 89.77 94.25 96.49 97.23 100 0.00 70.37 87.53 94.25 97.23 99.00 99.00 200 0.00 65.14 83.05 91.26 94.99 97.23 99.00 300 0.00 55.44 71.11 85.29 91.26 95.74 97.23 400 0.00 58.43 72.60 86.78 92.01 95.74 99.00

[0067] As can be seen from Table 6, the photodegradation efficiency of azithromycin within 3 h is little affected by the concentration of nitrate. The promotion effect of manganese porphyrin is stable and is not affected by the concentration of nitrate in the environment system.

[0068] Example Seven

[0069] A 100 mg / L azithromycin solution of 100 mL was prepared, and 5 mg of manganese porphyrin (i.e., the concentration of manganese porphyrin in the solution was 50 mg / L per liter) was added. A small amount of hydrochloric acid was used to adjust the pH of the solution to 7.0-9.0. Air was pumped into the solution to make the dissolved oxygen content of the solution 10-11. The solution was reacted under visible light. The light intensity of the visible light was controlled to be 3000 lx. Samples were taken every 30 minutes, and centrifugal separation, solid-phase extraction, and color development were performed. The absorbance was measured using a visible spectrophotometer.

[0070] Under the conditions of this example, the results of the photodegradation of azithromycin within 3 h are shown in Table 7.

[0071] Table 7: Photodegradation efficiency of azithromycin under comprehensive suitable conditions after adding manganese porphyrin (%)

[0072]

[0073]

[0074] As can be seen from Table 7, under the comprehensive suitable conditions, 5 mg / L of manganese porphyrin was added to azithromycin-containing wastewater, the pH of the wastewater was adjusted to 7.0-9.0, and the wastewater was oxygenated to make the dissolved oxygen content of the wastewater 10-11. The azithromycin was photodegraded under the light intensity of visible light of 3000 lx. The degradation efficiency of azithromycin after 3 h was 98.1-99.0%.

[0075] Comparative Example 1

[0076] A 100 mL solution of 100 mg / L azithromycin was prepared without adding manganese porphyrin, and a small amount of hydrochloric acid and sodium hydroxide solution was used to adjust the pH of the solution to 7.0. The solution was reacted under visible light, and samples were taken every 30 minutes. After centrifugal separation, solid-phase extraction, and color development, the absorbance was measured using a visible spectrophotometer.

[0077] Under the conditions of the present comparative example, the results of the photodegradation reaction of azithromycin within 3 hours are shown in Table 8:

[0078] Table 8: Photodegradation efficiency (%) of azithromycin without adding manganese porphyrin

[0079] Mn porphyrin 0 min 30 min 60 min 90 min 120 min 150 min 180 min 0 mg / L 0.00 4.69 8.43 12.90 15.89 21.11 24.84

[0080] As can be seen from the experimental results in Table 8, the degradation efficiency of azithromycin itself after 3 hours is only 24.8%.

[0081] Comparative Example 2

[0082] Silicon dioxide was prepared by the sol-gel method, and graphene oxide was prepared by improving the Hummer's method. In anhydrous methanol medium, silicon dioxide was used as a catalyst, and a UV lamp was used as a light source to obtain a graphene-loaded silicon dioxide photocatalyst by catalytic reduction. The photocatalyst was used to degrade azithromycin wastewater, and the degradation efficiency of azithromycin after 3 hours was 85-92%.

[0083] As can be seen from the above examples and comparative examples, the addition of the photosensitizer manganese porphyrin and the promotion of the degradation efficiency of azithromycin under suitable environmental conditions are obvious.

[0084] The principle of using manganese porphyrin to promote the photodegradation of azithromycin is as follows: after the addition of manganese porphyrin and irradiation with visible light, the number of active oxygen in the water body increases, among which the hydroxyl radical is the main active oxygen. Then, azithromycin is attacked by more hydroxyl radicals, which breaks the bond, opens the ring, and hydrolyzes at different positions (C-N and C-O), thereby achieving the purpose of degradation.

[0085] The specific process of the principle is as follows:

[0086] Azithromycin is attacked by active oxygen, which breaks the bond, opens the ring, and hydrolyzes at different positions, obtaining different degradation products. From Figure 8 It can be seen that the first attack of active oxygen causes the L-aldotetrosose ring to separate azithromycin to form cladinose azithromycin P2 (obtained from a, c in Figure 7 ), which further attacks from the same position to obtain P3 (obtained from a in Figure 7 ), and the loss of the deaminated ring leads to dehydration to form P4 (obtained fromFigure 7 (obtained from b and e), the breaking of the CN bond and the loss of N-methylmethylamine in P4 will further form P5 (from b and e). Figure 7 (obtained from b and e).

[0087] like Figure 7 The figures shown are MS spectra of azithromycin degradation products provided in this embodiment of the invention. Figure a shows the mass-to-charge ratio of the positive ion degradation product generated after 1.5 hours of visible light degradation (1.543 min), Figure b shows the mass-to-charge ratio of the positive ion degradation product generated after 1.5 hours of visible light degradation (2.314 min), Figure c shows the mass-to-charge ratio of the positive ion degradation product generated after 3 hours of visible light degradation (1.995 min), and Figure d shows the mass-to-charge ratio of the positive ion degradation product generated after 3 hours of visible light degradation (1.995 min). Figure e shows the mass-to-charge ratio of the negative ion degradation products after 1.5 hours of visible light degradation with the addition of the photosensitizer manganese porphyrin, and the generation of the positive ion degradation products after 1.5 hours of visible light degradation with a time of 2.029 min. Figure f shows the mass-to-charge ratio of the negative ion degradation products after 1.5 hours of visible light degradation with the addition of the photosensitizer manganese porphyrin, and the generation of the positive ion degradation products after 3 hours of visible light degradation with the addition of the photosensitizer manganese porphyrin, with a time of 2.331 min.

[0088] Depend on Figure 7 It is known that during the reaction, CN, CO, and CH bonds continuously break, thereby generating a large number of fragments with relatively small mass-charge ratios (fragments of P4 with m / z = 115 and 83 obtained from a and e, fragments of N',N'-bis(demethyl)azithromycin P6 with m / z = 376 obtained from b and e, and fragments of P6 with m / z = 375 obtained from c). At the same time, a small amount of azithromycin impurity M is generated (fragments of m / z = 750 obtained from b and e). Azithromycin is eventually degraded into two specific simple compounds (fragments of m / z = 83 and 60 obtained from e and g). The final degradation products of azithromycin are simple and have low concentrations, and they lead to the loss of azithromycin's antibiotic resistance, further reducing the environmental harm of azithromycin wastewater.

[0089] The present invention also provides an application of photodegradation of azithromycin in water, wherein any of the methods described herein for promoting photodegradation of azithromycin in water is used to photodegrade azithromycin in water.

[0090] The present application uses visible light as light source, adds manganese porphyrin to carry out photodegradation of azithromycin, the photosensitizer manganese porphyrin has the characteristics of environmental friendliness, non-toxicity and reusability, the degradation efficiency of 100mg / L azithromycin with 50mg / L manganese porphyrin under visible light within 3h can reach 97.23%, and the intermediate product is non-toxic, which is an efficient, green and economic method for removing azithromycin pollution in the environment.

[0091] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A method of promoting photodegradation of azithromycin in an aqueous body, characterized in that, The method comprises adding manganese porphyrin into the wastewater containing azithromycin, and performing photodegradation of azithromycin under visible light, wherein the concentration of the manganese porphyrin in the wastewater is 50 mg / L-100 mg / L per liter of wastewater.

2. The method of facilitating photodegradation of azithromycin in an aqueous body according to claim 1, wherein, The method comprises adjusting the pH of the wastewater mixed with manganese porphyrin to 7-9.

3. The method of facilitating photodegradation of azithromycin in an aqueous body according to claim 1, wherein, The method comprises oxygenating the wastewater mixed with manganese porphyrin to ensure that the dissolved oxygen content in the wastewater is greater than 10.

4. The method of facilitating photodegradation of azithromycin in an aqueous body according to claim 1, wherein, The concentration of the manganese porphyrin in the wastewater is 50 mg / L per liter of wastewater.

5. The method of facilitating photodegradation of azithromycin in an aqueous body according to claim 1, wherein, The illumination intensity of the visible light is 3000 lx-4000 lx.

6. Use of the photodegradation of azithromycin in a body of water, characterized in that, The method for promoting photodegradation of azithromycin in water bodies according to any one of claims 1-5 is used.

Images