Preparation method and application of Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water

Abstract

The present invention discloses a preparation method and application of an Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water. The preparation method includes the following steps: S1. Prepare a carrier Zn-Ti organic framework material; S2. Prepare TiC / TiN-CNTs; S3. Etch with ammonia water to obtain TiC / TiN-NH2; S4. Chelate and load manganese and perform ultrasonic cavitation treatment to obtain an ozone catalyst for degrading chloroquine phosphate in water, namely Mn@(TiC-TiN)-NH2. The Mn@(TiC-TiN)-NH2 catalyst prepared by the present invention has a large specific surface area and high catalytic ability for ozone, and can achieve a decomposition efficiency of more than 94% for chloroquine phosphate pollutants at the mg / L level within 40 minutes, and can effectively purify pharmaceutical wastewater such as chloroquine phosphate.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment and relates to a catalyst for degrading chloroquine phosphate pharmaceutical wastewater, and in particular to a preparation method and application of a Mn@(TiC-TiN)-NH2 ozone catalyst for catalyzing O3-H2O2 to degrade chloroquine phosphate in wastewater. Background Art

[0002] Chloroquine phosphate (CQP) is often used to treat rheumatism, malaria, systemic lupus erythematosus, etc., and studies have found that chloroquine phosphate has a certain effect on novel coronavirus infection. However, CQP accumulated in the environment can cause toxic reactions in the human central nervous system, cardiovascular system, and digestive system, have toxic effects on aquatic organisms, and destroy the balance of the aquatic ecosystem. CQP is easily soluble in water and difficult to biodegrade, so seeking a mild, efficient and low-cost method for degrading antiviral drugs has become a new hotspot in the field of environmental technology.

[0003] For the removal of refractory pollutants, the most widely studied and applied technology is advanced oxidation technology (AOPs). The main oxidizing agent in the degradation process of pollutants is reactive oxygen species (ROS), including free radicals such as ·OH, SO4·- and non-free radicals such as H2O2 and O3. However, ozone has a short residence time in water and is costly. The degradation of pollutants by ozone alone is only preliminary, and the oxidation reaction is not thorough. For refractory pharmaceutical wastewater, even if hydrogen peroxide is added, the removal rate is still not high. Existing catalysts have certain problems in terms of stability, adsorption, recyclability and treatment cost. In order to improve the stability, adsorption, recyclability of the catalyst and control the treatment cost of chloroquine phosphate wastewater, it is necessary to select a suitable carrier, structure and preparation method to improve the performance of the catalyst, achieve efficient activation of ozone and H2O2, and improve the efficiency of catalytic oxidation degradation of chloroquine phosphate in wastewater and reduce the cost of chloroquine phosphate wastewater treatment. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water.

[0005] According to one aspect of the present invention, there is provided a method for preparing a Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water, comprising the following steps:

[0006] S1. Weigh zinc oxide powder, titanium oxide powder, dimethylimidazole and 1 mL of methanol in a certain proportion, add them to a ball mill, use a planetary ball mill to perform ball milling, make the zinc oxide powder, titanium oxide powder and dimethylimidazole powder and mix them thoroughly to obtain a ball-milled mixture, take out the ball-milled mixture, put it into a polytetrafluoroethylene-lined reactor, place it in an oven, and dry it at a certain temperature for a period of time to obtain a carrier mixture, i.e., a Zn-Ti organic framework material;

[0007] S2. Take out the Zn-Ti organic framework material prepared in step S1 and grind it, place it in a tube furnace, and heat it to 1100-1400°C at a certain heating rate under the protection of inert gas to obtain TiC / TiN-CNTs;

[0008] S3. TiC / TiN-CNTs were etched in dilute ammonia, washed three times with dilute ammonia, and dried in an oven at 60°C to obtain TiC / TiN-NH2;

[0009] S4. Add a certain amount of TiC / TiN-NH2 to the manganese source chelated ion solution, place it in a nitrogen atmosphere, and carry out ultrasonic reaction at 50-80°C for 1-4 hours. After the ultrasonic reaction, place it in a vacuum oven at 100-150°C for drying for 2-4 hours to obtain an ozone catalyst for degrading chloroquine phosphate in water, namely Mn@(TiC-TiN)-NH2.

[0010] In this preparation method, the carrier TiC / TiN-CNTs itself has a large specific surface area and porosity. The carrier is prepared by sintering, using the Zn-Ti organic framework as a precursor, and the internal Zn-Ti occupies the metal site. High temperature is used to enhance the coordination between Zn, Ti and dimethylimidazole to prevent the detachment of Ti. The high temperature of 1100°C exceeds the boiling point of Zn to effectively remove the internal Zn. In this process, the evaporation path of Zn forms channels inside the catalyst to further increase the specific surface area and promote the formation of the core-shell structure of the catalyst. Dimethylimidazole and nitrogen provide carbon and nitrogen sources to promote the generation of a small amount of TiC-TiN to improve the stability of the catalyst.

[0011] In this preparation method, ammonia water is used to etch the carrier to achieve the purpose of removing Zn, and at the same time, amino groups are provided to the catalyst, which enhances the adsorption of ozone through hydrogen bonding and provides catalyst activity. Nitrilotriacetic acid is used as a chelating agent to form a multidentate chelate with Mn, enhance the stability of Mn to prevent its leaching during the reaction, and is more economical and environmentally friendly than other chelating agents. Ultrasonic hydrothermal treatment accelerates the formation of catalyst particles, so that manganese ions are evenly dispersed on the catalyst surface, and cavitation forms defects inside the catalyst, further increasing the specific surface area of ​​the catalyst.

[0012] In some embodiments, in step S1, the mass ratio of zinc oxide powder, titanium oxide powder and dimethylimidazole particles is 1: (0.5-2): (3-6), the rotation speed of the ball milling treatment is 400 r / min, the ball milling treatment time is 2 h, the drying reaction temperature is 200° C., and the drying reaction time is 12 h.

[0013] In some embodiments, the heating rate in step S2 is 5° C. / min and the calcination time is 2 h.

[0014] In some embodiments, the ammonia water in step S3 is prepared by mixing concentrated ammonia water and pure water in a volume ratio of 1:(3-6).

[0015] In some embodiments, the manganese source chelated ion solution in step S4 is prepared by adding manganese sulfate to a nitrilotriacetic acid solution, the pH value of the nitrilotriacetic acid solution is 8, the mass volume ratio of nitrilotriacetic acid to water in the nitrilotriacetic acid solution is 1-4:100-300, and the mass volume ratio of manganese sulfate to the nitrilotriacetic acid solution in the manganese source chelated ion solution is 4-8:100-300.

[0016] According to another aspect of the present invention, an ozone catalyst for degrading chloroquine phosphate in water is provided for use in degrading chloroquine phosphate in water.

[0017] According to another aspect of the present invention, a method for degrading chloroquine phosphate in water is provided, comprising the following steps:

[0018] A1. Add the wastewater containing chloroquine phosphate to the reaction flask, and add a certain amount of Mn@(TiC-TiN)-NH2 to the reaction flask;

[0019] A2. Connect the ozone generator to the air source and the titanium aeration head, turn on the power of the ozone generator, and adjust the ozone flow rate. After the ozone is stably produced, place the titanium aeration head in the reaction bottle and add a certain amount of hydrogen peroxide into the reaction bottle;

[0020] A3. Place the reaction bottle on a magnetic stirrer for stirring, then start timing. During the reaction time, take 1 mL of the reaction solution into the liquid phase bottle at regular intervals. After sampling, add sodium thiosulfate to the reaction bottle to terminate the reaction.

[0021] A4. The reaction solution obtained by multiple sampling is subjected to high performance liquid chromatography to determine the concentration of chloroquine phosphate in the reaction solution sampled each time.

[0022] In some embodiments, the concentration of chloroquine phosphate in the wastewater containing chloroquine phosphate in step A1 is 5 to 10 ppm, and the added concentration of Mn@(TiC-TiN)-NH2 is 0.1 to 0.5 g / L.

[0023] In some embodiments, in step A2, the gas flow rate of the ozone generator is 1.5 to 2.0 L / min, the ozone output of the ozone generator is 1.6 to 2.0 g / h, the mass volume fraction of the hydrogen peroxide solution is 3%, the amount of hydrogen peroxide solution added is 20 to 50 μL, and the reaction time is 0 to 40 min.

[0024] In some embodiments, the concentration of the sodium thiosulfate solution is 0.15 mM, and the amount of the sodium thiosulfate solution added is 15 to 20 μL.

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention uses TiC / TiN-CNTs organic framework material as a carrier, and the prepared catalyst Mn@(TiC-TiN)-NH2 is more stable, effectively preventing the leaching of Mn in the catalyst and causing no pollution to the environment;

[0027] 2. The catalyst carrier of the present invention is prepared by a solidification method, which reduces the consumption of organic solvents. The high-temperature calcination removes Zn inside the carrier to form pores, which promotes the formation of a core-shell structure and increases the specific surface area of ​​the catalyst. At the same time, the organic ligand and nitrogen provide nitrogen and carbon sources for the formation of TiC-TiN, which promotes the formation of a small amount of TiC-TiN and enhances the overall stability of the catalyst.

[0028] 3. In the present invention, ammonia water is used to etch the residual Zn in the catalyst carrier, and amino groups are provided to the catalyst, so that the catalyst can enhance the adsorption of ozone molecules through hydrogen bonding, thereby improving the activity of the catalyst and adjusting the electron density of the metal center, thereby affecting the redox properties of the catalyst;

[0029] 4. The chelation of manganese ions in the preparation of the catalyst Mn@(TiC-TiN)-NH2 was carried out by ultrasonic hydrothermal treatment, which effectively and evenly dispersed the Mn ions and promoted the formation of particle catalysts. At the same time, ultrasonic cavitation formed defects inside the catalyst, further increasing the specific surface area of ​​the catalyst.

[0030] 5. The Mn@(TiC-TiN)-NH2 catalyst prepared by the present invention can achieve a decomposition efficiency of more than 94% for mg / L-level chloroquine phosphate pollutants within 40 minutes, and can effectively purify pharmaceutical wastewater such as chloroquine phosphate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a scanning electron microscope photograph of the catalyst Mn@(TiC-TiN)-NH2 in Example 1 of the present invention.

[0032] Figure 2 This is the XRD diagram of the catalyst Mn@(TiC-TiN)-NH2 in Example 1 of the present invention.

[0033] Figure 3 It is the degradation curve diagram of chloroquine phosphate in embodiment 2 of the present invention.

[0034] Figure 4 This is a degradation curve diagram of chloroquine phosphate with different dosages of Mn@(TiC-TiN)-NH2 in Example 3 of the present invention.

[0035] Figure 5 This is a comparison chart of the degradation rate of chloroquine phosphate with different dosages of Mn@(TiC-TiN)-NH2 in Example 3 of the present invention.

[0036] Figure 6 The figure is a comparison diagram of the degradation rate of chloroquine phosphate at different initial pH values ​​in Example 4 of the present invention.

[0037] Figure 7 The figure is a graph showing the degradation of chloroquine phosphate at different dosages of hydrogen peroxide in Example 5 of the present invention.

[0038] Figure 8 The figure is a comparison diagram of the degradation rate of chloroquine phosphate at different dosages of hydrogen peroxide in Example 5 of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below through specific implementation cases. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of protection of the present invention. After reading the present invention, the modifications of various equivalent forms of the present invention by those skilled in the art are all limited by the claims attached to this application. Unless otherwise specified, all raw materials and reagents of the present invention are raw materials and reagents that can be purchased in the conventional market.

[0040] Example 1 Preparation of a Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water

[0041] A method for preparing a Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water comprises the following steps:

[0042] S1. Take 3.324g of zinc oxide powder, 3.261g of titanium oxide powder, 13.414g of dimethylimidazole particles and 1mL of methanol, add them to a ball mill, use a planetary ball mill for ball milling, the ball mill speed is 400r / min, ball milling for 2h, so that zinc oxide, titanium oxide and dimethylimidazole are in powder form and fully mixed to obtain a ball-milled mixture, take out the ball-milled mixture, put it into a polytetrafluoroethylene-lined reactor, place it in an oven at 200°C for drying and reaction for 12h to obtain a carrier mixture, i.e., a Zn-Ti organic framework material;

[0043] S2. Take out the Zn-Ti organic framework material prepared in step S1 and grind it, place it in a tube furnace, and heat it to 1100°C at a heating rate of 5°C / min under the protection of inert gas N2 to obtain TiC / TiN-CNTs;

[0044] S3. TiC / TiN-CNTs were etched in dilute ammonia for 4 h, washed with dilute ammonia for 3 times, and dried in an oven at 60 ° C to obtain TiC / TiN-NH2;

[0045] S4. Weigh 2g of nitrilotriacetic acid (NTA) and add it to 200mL of water and mix well. Then adjust the pH value of the solution to 8 with ammonia water. Weigh 6g of manganese sulfate and add it to the nitrilotriacetic acid solution. Stir and mix well to prepare a manganese source chelated ion solution. Add 8.64g of TiC / TiN-NH2 to the manganese source chelated ion solution. Place it in a nitrogen atmosphere and carry out ultrasonic reaction at 70°C for 2h. After the ultrasonic reaction is completed, filter it and place it in a vacuum oven at 120°C for drying for 4h to obtain an ozone catalyst for degrading chloroquine phosphate in water, namely Mn@(TiC-TiN)-NH2.

[0046] like Figure 1 As shown, the Mn@(TiC-TiN)-NH2 ozone catalyst prepared by the present invention is spherical, and the evaporation of internal Zn causes the catalyst to form more pores. At the same time, ammonia etching increases the surface defects of the catalyst, effectively increasing the specific surface area of ​​the catalyst; ultrasonic hydrothermal treatment causes the catalyst to be distributed in a microsphere shape, and Mn is evenly chelated on the surface of the loaded catalyst.

[0047] like Figure 2 As shown, the ozone catalyst prepared by the process of the present invention successfully synthesizes TiC-TiN, and part of the amino groups are combined on the organic framework structure of the catalyst; the manganese element on the catalyst mainly exists in the form of MnO2.

[0048] Example 2

[0049] A method for degrading chloroquine phosphate in water comprises the following steps:

[0050] A1. 350 mL of wastewater containing 10 ppm chloroquine phosphate was added to a 400 mL three-necked cylindrical flask, and 35 mg of catalyst Mn@(TiC-TiN)-NH2 was added to the reaction flask;

[0051] A2. Connect the ozone generator to the air source and the titanium aeration head, turn on the power of the ozone generator, and adjust the ozone flow rate to 1.55L / min. After the ozone is stably produced, place the titanium aeration head in the reaction bottle, and add 36μL of 3% hydrogen peroxide (i.e., the concentration of hydrogen peroxide in the solution is 100mM) into the reaction bottle;

[0052] A3. Place the reaction bottle on a magnetic stirrer for stirring, then start timing, at 0, 1, 3, 5, 7, 10, 15, 20, 30, 40 min, take 1 ml of the reaction solution and place it in a 1.5 mL liquid phase bottle. After sampling, add 20 μL of 0.15 mM sodium thiosulfate solution to the reaction bottle to terminate the reaction;

[0053] A4. The reaction solution sampled in step A3 is subjected to high performance liquid chromatography to measure the concentration of chloroquine phosphate in the reaction solution sampled each time.

[0054] like Figure 3 As shown, the Mn@(TiC-TiN)-NH2 ozone catalyst prepared by the present invention can decompose mg / L-level chloroquine phosphate pollutants with an efficiency of more than 94% within 40 minutes, and can effectively purify wastewater containing chloroquine phosphate drugs.

[0055] Example 3 Effect of different dosages of Mn@(TiC-TiN)-NH2 on the degradation of chloroquine phosphate

[0056] In this example, Mn@(TiC-TiN)-NH2 solutions of different concentrations were used as experimental objects. The specific concentrations of the Mn@(TiC-TiN)-NH2 solutions were set to 0, 50, 100, 200, and 500 mg / L. The wastewater containing 10 ppm of chloroquine phosphate was degraded by referring to the method of Example 2, and the effects of different dosages of the Mn@(TiC-TiN)-NH2 catalyst on the degradation of chloroquine phosphate were investigated.

[0057] like Figure 4 , Figure 5 As shown, under the same dosage volume, the Mn@(TiC-TiN)-NH2 solution with a concentration of 100 mg / L has the fastest degradation rate for chloroquine phosphate and the greatest degree of degradation for chloroquine phosphate in wastewater, with the decomposition rate of chloroquine phosphate reaching 96.27% within 40 minutes.

[0058] Example 4 Effect of different initial pH values ​​on the degradation of chloroquine phosphate

[0059] In this example, different initial pH values ​​are used as experimental objects, and the initial pH values ​​are set to 3, 5, 7, 8, and 9. The wastewater containing 10 ppm of chloroquine phosphate is degraded by referring to the method of Example 2 to examine the effect of different initial pH values ​​on the degradation of chloroquine phosphate.

[0060] like Figure 6 As shown, the initial pH value of the reaction system is in the range of 3-9, which has little effect on the degradation of chloroquine phosphate in the system.

[0061] Example 5 Effect of different dosages of hydrogen peroxide on the degradation of chloroquine phosphate

[0062] In this example, different dosages of hydrogen peroxide are used as experimental objects. The dosage of hydrogen peroxide is set to 0, 20, 50, 100, 200, and 300 μM. The wastewater containing 10 ppm of chloroquine phosphate is degraded by referring to the method of Example 2 to investigate the effect of different dosages of hydrogen peroxide on the degradation of chloroquine phosphate.

[0063] like Figure 7 , Figure 8 As shown, when the hydrogen peroxide dosage is 100, 200, and 300 μM, the degradation rate of chloroquine phosphate in the wastewater is very fast, and the decomposition rate of chloroquine phosphate reaches 96.27%, 97.08%, and 98.92%, respectively. When the hydrogen peroxide dosage reaches 100 μM, as the dosage increases, the degradation efficiency and the decomposition rate of chloroquine phosphate do not increase significantly, therefore, the hydrogen peroxide dosage of 100 μM is most suitable in this method.

[0064] In summary, the degradation method was explored and it was concluded that under optimal conditions, the dosage of Mn@(TiC-TiN)-NH2 catalyst was 100 mg / L, the dosage of H2O2 was 100 μM, and the initial pH value had little effect on the degradation of the system.

[0065] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements may be made without departing from the inventive concept of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A method for preparing a Mn@(TiC-TiN)-NH2 ozone catalyst for degrading chloroquine phosphate in water, characterized in that: The steps include: S1. Weigh zinc oxide powder, titanium oxide powder, dimethylimidazole and 1 mL of methanol in a certain proportion, add them to a ball mill, use a planetary ball mill to perform ball milling, make zinc oxide, titanium oxide and dimethylimidazole powder and mix them thoroughly to obtain a ball milled mixture, take out the ball milled mixture, put it into a polytetrafluoroethylene-lined reactor, place it in an oven, and dry it at a certain temperature for a period of time to obtain a carrier mixture, i.e., a Zn-Ti organic framework material; S2. Taking out the Zn-Ti organic framework material prepared in step S1 and grinding it, placing it in a tube furnace, heating it to 1100-1400° C. at a certain heating rate under the protection of an inert gas, and calcining it to obtain TiC / TiN-CNTs; S3. The TiC / TiN-CNTs were etched in dilute ammonia, washed three times with dilute ammonia, and dried in an oven at 60 ° C to obtain TiC / TiN-NH2; S4. Add a certain amount of the TiC / TiN-NH2 into the manganese source chelated ion solution, place it in a nitrogen atmosphere, and carry out ultrasonic reaction at 50-80°C for 1-4 hours. After the ultrasonic reaction, place it in a vacuum oven at 100-150°C for drying for 2-4 hours to obtain an ozone catalyst for degrading chloroquine phosphate in water, namely Mn@(TiC-TiN)-NH2.

2. The preparation method according to claim 1, characterized in that: In the step S1, the mass ratio of zinc oxide powder, titanium oxide powder and dimethylimidazole particles is 1: (0.5-2): (3-6), the rotation speed of the ball milling treatment is 400 r / min, the ball milling treatment time is 2 h, the drying reaction temperature is 200° C., and the drying reaction time is 12 h.

3. The preparation method according to claim 1, characterized in that: The heating rate in step S2 is 5° C. / min, and the calcination time is 2 h.

4. The preparation method according to claim 1, characterized in that: The dilute ammonia water in step S3 is prepared by mixing concentrated ammonia water and pure water in a volume ratio of 1: (3-6).

5. The preparation method according to claim 1, characterized in that: In step S4, the manganese source chelated ion solution is prepared by adding manganese sulfate to a nitrilotriacetic acid solution, the pH value of the nitrilotriacetic acid solution is 8, the mass volume ratio of nitrilotriacetic acid to water in the nitrilotriacetic acid solution is 1-4:100-300, and the mass volume ratio of manganese sulfate to the nitrilotriacetic acid solution in the manganese source chelated ion solution is 4-8:100-300.

6. the application of an ozone catalyst for degrading chloroquine phosphate in water obtained by the preparation method described in any one of claims 1 to 5 in degrading chloroquine phosphate in water.

7. A method for degrading chloroquine phosphate in water, characterized in that, The following steps are involved: A1. Adding the wastewater containing chloroquine phosphate to a reaction flask, adding a certain amount of Mn@(TiC-TiN)-NH2 prepared by the preparation method according to claim 1 to the reaction flask; A2. Connect the ozone generator to the air source and the titanium aeration head, turn on the power of the ozone generator, and adjust the ozone flow rate. After the ozone is stably produced, place the titanium aeration head in the reaction bottle, and add a certain amount of hydrogen peroxide into the reaction bottle; A3. The reaction bottle was placed on a magnetic stirrer for stirring, and then the timing was started. During the reaction time, 1 mL of the reaction solution was taken into the liquid phase bottle at regular intervals for several times. After the sampling was completed, sodium thiosulfate was added to the reaction bottle to terminate the reaction; A4. The reaction solution obtained by multiple samplings is subjected to high performance liquid chromatography to determine the concentration of chloroquine phosphate in the reaction solution sampled each time.

8. A method for degrading chloroquine phosphate in water according to claim 7, characterized in that, The concentration of chloroquine phosphate in the wastewater containing chloroquine phosphate in step A1 is 5-10 ppm, and the addition concentration of Mn@(TiC-TiN)-NH2 is 0.1-0.5 g / L.

9. A method for degrading chloroquine phosphate in water according to claim 7, characterized in that, In step A2, the gas flow rate of the ozone generator is 1.5-2.0 L / min, the ozone output of the ozone generator is 1.6-2.0 g / h, the mass volume fraction of the hydrogen peroxide solution is 3%, the addition amount of the hydrogen peroxide solution is 20-50 μL, and the reaction time is 0-40 min.

10. A method for degrading chloroquine phosphate in water according to claim 7, characterized in that, The concentration of the sodium thiosulfate solution is 0.15 mM, and the amount of the sodium thiosulfate solution added is 15-20 μL.

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