Titanium-cobalt-nickel composite nanosheet catalyst and its preparation method and application

Abstract

The invention discloses a method for preparing a titanium-cobalt-nickel composite nanosheet catalyst, comprising the following steps: step 1: dissolving cobalt acetate in ethylene glycol, stirring continuously, and obtaining an organic solution A; step 2: dissolving nickel acetate in ethylene glycol, stirring continuously, and obtaining an organic solution B; step 3: dissolving tetrabutyl titanate in ethylene glycol, stirring continuously, and obtaining an organic solution C; step 4: mixing organic solution A, organic solution B and organic solution C, stirring continuously, and obtaining a mixed organic solution D; step 5: hydrothermally reacting the mixed organic solution D to obtain a reaction mixture E, and standing to room temperature; step 6: after the reaction mixture E is obviously layered, removing the liquid phase product at the top, and burning the solid phase product at the bottom; step 7: after the burning reaction, placing the reaction product F on a steel plate for quenching, and obtaining a titanium-cobalt-nickel composite nanosheet catalyst sample. The catalyst prepared by the preparation method provided by the invention can efficiently and stably remove pollutants in medical wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of catalytic materials, and in particular to a titanium-cobalt-nickel composite nanosheet catalyst and a preparation method and application thereof. Background Art

[0002] Pharmaceutical wastewater has the characteristics of high concentration of organic pollutants, difficulty in biodegradation, and high content of toxic and harmful substances. Most of the residual antibiotics, halogenated compounds, organic solvents, ether compounds, nitro compounds, etc. in the wastewater are difficult to degrade, so traditional biological treatment technology cannot effectively treat this type of wastewater.

[0003] Catalytic wet oxidation is an advanced oxidation technology based on high temperature and high pressure hydrothermal reaction. Organic pollutants are oxidized into intermediate products or mineralized into carbon dioxide, water and related inorganic salts in the presence of solid catalysts. From an environmental perspective, the use of catalytic wet oxidation (CwAO) process to remove pollutants from pharmaceutical wastewater is a promising option. The development of efficient and stable catalytic materials is crucial for the application of catalytic wet oxidation technology. The addition of efficient catalysts can shorten the reaction process and achieve effective degradation of organic pollutants under mild conditions.

[0004] However, most catalysts currently have problems such as high cost, limited treatment effect, and poor stability. In order to solve the above problems, the present invention is presented. Summary of the invention

[0005] The present invention aims to provide a titanium-cobalt-nickel composite nanosheet catalyst and a preparation method and application thereof. The prepared catalyst can effectively remove pollutants in medical wastewater and reduce the toxicity of the wastewater.

[0006] Based on the above problems, one of the technical solutions provided by the present invention is:

[0007] A method for preparing a titanium-cobalt-nickel composite nanosheet catalyst comprises the following steps:

[0008] Step 1: dissolving cobalt acetate in ethylene glycol, stirring continuously, to obtain an organic solution A;

[0009] Step 2: dissolving nickel acetate in ethylene glycol, stirring continuously, to obtain an organic solution B;

[0010] Step 3: dissolving tetrabutyl titanate in ethylene glycol, stirring continuously, to obtain an organic solution C;

[0011] Step 4: Mix the organic solution A, the organic solution B and the organic solution C, and continue stirring to obtain a mixed organic solution D;

[0012] Step 5: placing the mixed organic solution D in a hydrothermal reactor for hydrothermal reaction to obtain a reaction mixture E, and allowing it to stand to room temperature;

[0013] Step 6: After the reaction mixture E is clearly separated into layers, the liquid phase product on the top is removed, and the solid phase product on the bottom is burned for reaction;

[0014] Step 7: After the calcination reaction, the reaction product F is directly placed on a steel plate for quenching to obtain the final titanium-cobalt-nickel composite nanosheet catalyst sample.

[0015] Furthermore, in step 1, the mass ratio of cobalt acetate to ethylene glycol is 1:10-20.

[0016] Furthermore, in step 2, the mass ratio of nickel acetate to ethylene glycol is 1:10-20.

[0017] Furthermore, in step 3, the mass ratio of tetrabutyl titanate to ethylene glycol is 1:7-12.

[0018] Furthermore, in step 4, the molar ratio of cobalt, nickel and titanium elements in the organic solution D is x:1-x:1, wherein 0.2≤x≤0.4.

[0019] Furthermore, in step 5, the temperature of the hydrothermal reaction is 140-160° C., and the reaction time is 6-8 hours.

[0020] Furthermore, in step 6, the temperature of the calcination reaction is 750-850° C., and the reaction time is 6-8 hours.

[0021] Furthermore, in step 7, the temperature of the steel plate is 0° C., which is controlled by an ice-water mixture water bath.

[0022] Based on the above problems, the second technical solution provided by the present invention is:

[0023] Any one of the above preparation methods can produce a titanium-cobalt-nickel composite nanosheet catalyst.

[0024] Based on the above problems, the third technical solution provided by the present invention is:

[0025] Application of any of the above titanium-cobalt-nickel composite nanosheet catalysts in catalytic wet oxidation treatment of pharmaceutical wastewater.

[0026] Furthermore, the COD concentration of the pharmaceutical wastewater is 30,500 to 41,000 mg / L; the temperature of the catalytic wet oxidation reaction is 150° C. to 190° C., the reaction time is 0.5 to 2.5 h, and the amount of catalyst added is 0.20 to 1.60 g / L.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] The catalyst is a composite nanosheet, which is used in the catalytic wet oxidation treatment of pharmaceutical wastewater and can effectively and stably remove pollutants in the wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. The accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0030] Figure 1 The scanning electron microscope results of the catalyst samples synthesized in Examples 1 and 2 are shown;

[0031] Figure 2 The scanning electron microscope results of the catalyst samples synthesized in Examples 3 and 4 are shown;

[0032] Figure 3 The scanning electron microscope results of the catalyst samples synthesized in Examples 5 and 6 are shown;

[0033] Figure 4 The X-ray diffraction results of the catalyst samples synthesized in Examples 1 and 2 are as follows;

[0034] Figure 5 The X-ray diffraction results of the catalyst samples synthesized in Examples 3 and 4 are as follows;

[0035] Figure 6 The X-ray diffraction results of the catalyst samples synthesized in Examples 5 and 6 are as follows;

[0036] Figure 7 The present invention is a process flow chart of the preparation process. DETAILED DESCRIPTION

[0037] The above scheme is further described below in conjunction with specific examples. It should be understood that these examples are used to illustrate the present invention and are not limited to the scope of the present invention. The implementation conditions adopted in the examples can be further adjusted according to the conditions of the specific manufacturer, and the unspecified implementation conditions are usually the conditions in conventional experiments.

[0038] Example 1

[0039] A method for preparing a titanium-cobalt-nickel composite nanosheet catalyst comprises the following steps:

[0040] 1) dissolving cobalt acetate in ethylene glycol and stirring for 2 hours to obtain an organic solution A, wherein the mass ratio of cobalt acetate to ethylene glycol is 1:10;

[0041] 2) dissolving nickel acetate in ethylene glycol and stirring for 3 hours to obtain an organic solution B, wherein the mass ratio of nickel acetate to ethylene glycol is 1:10;

[0042] 3) dissolving tetrabutyl titanate in ethylene glycol and stirring for 2 hours to obtain an organic solution C, wherein the mass ratio of tetrabutyl titanate to ethylene glycol is 1:7;

[0043] 4) Mixing organic solution A, organic solution B and organic solution C, and stirring for 2 hours to obtain a mixed organic solution D, wherein the molar ratio of cobalt, nickel and titanium elements after mixing is 0.2:0.8:1;

[0044] 5) placing the mixed organic solution D in a hydrothermal reactor for hydrothermal reaction at 140° C. for 6 h to obtain a reaction mixture E, which was allowed to stand until it reached room temperature;

[0045] 6) After the reaction mixture E is clearly separated into layers, the liquid phase product on the top is removed, and the solid phase product on the bottom is placed in a muffle furnace and calcined at 750° C. for 6 hours;

[0046] 7) After the calcination reaction is completed, the reaction product F is directly placed on a steel plate for quenching, and the temperature of the steel plate is 0° C. and controlled by an ice-water mixture water bath to obtain the final titanium-cobalt-nickel composite nanosheet catalyst sample, and the thickness of the nanosheet is about 100 to 200 nm.

[0047] The titanium-cobalt-nickel composite nanosheet catalyst prepared in this example is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0048] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnet rotary stirring reactor, add a certain amount of catalyst at the same time, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct a wet oxidation experiment on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8MPa. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 30 500mg / L, and the COD removal rate = (COD 反应前 -COD 反应后 )÷COD 反应前 ×100%.

[0049] Table 1 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0050]

[0051] It can be seen from the experimental results in Table 1 that when no catalyst is added, wet oxidation treatment of pharmaceutical wastewater has a certain effect, but it is very limited. After adding a small amount of catalyst, under high temperature excitation, the electrons on the catalyst valence band are excited to the conduction band to form strongly reducing thermally excited electrons, and at the same time, strongly oxidizing thermally excited holes are formed in the valence band. On the one hand, thermally excited electrons and holes can use their own strong reducing and oxidizing properties to degrade pollutants. On the other hand, thermally excited electrons can also react with oxygen molecules to form superoxide radicals with strong reducing properties, and thermally excited holes can also react with water molecules to form hydroxyl radicals with strong reducing properties. The formation of superoxide and hydroxyl radicals contributes to the efficient degradation of pollutants. Finally, under the joint action of the two mechanisms, the treatment efficiency of catalytic wet oxidation for pharmaceutical wastewater is significantly improved. And with the continuous increase in the amount of catalyst, the efficiency of catalytic wet oxidation increases significantly.

[0052] When no catalyst was added, the reaction temperature was 150℃, and the reaction time was 2.5h, the COD removal rate of pharmaceutical wastewater was only 18.6%. When the amount of catalyst added was 0.25g / L and the reaction time was 2.5h, the treatment efficiency was increased to 48.8%, and the removal rate was increased by 30.2%; when the amount of catalyst was increased to 0.8g / L and the reaction time was 2.5h, the treatment efficiency was 61.1%; when the amount of catalyst was increased to 1.6g / L, the catalytic wet oxidation efficiency was further increased to 72.2%, an increase of 53.6% compared with the case without catalyst under similar conditions. These results show that the addition of catalyst can significantly improve the removal rate of pharmaceutical wastewater.

[0053] Example 2

[0054] The titanium-cobalt-nickel composite nanosheet catalyst prepared in Example 1 is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0055] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnet rotary stirring reactor, add a certain amount of catalyst at the same time, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct a wet oxidation experiment on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8MPa. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 33480mg / L, and the COD removal rate = (COD 反应前 -COD 反应后 )÷COD 反应前 ×100%.

[0056] Table 2 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0057]

[0058]

[0059] It can be seen from the experimental results in Table 2 that the addition of catalyst can significantly improve the efficiency of wet oxidation treatment of pharmaceutical wastewater. For example, when no catalyst is added, the COD removal rate of pharmaceutical wastewater is 27.1% when the reaction temperature is 170°C and the reaction time is 2.5h. When the amount of catalyst added is 0.3g / L and the reaction time is 2.5h, the treatment efficiency is increased to 58.9%, and the removal rate is increased by 31.8%; when the amount of catalyst is increased to 0.7g / L and the reaction time is 2.5h, the treatment efficiency is 73.2%, which is 46.1% higher than when no catalyst is added; when the amount of catalyst is increased to 1.5g / L, the catalytic wet oxidation efficiency is further increased to 84.5%, which is 57.4% higher than when no catalyst is added under similar conditions.

[0060] Example 3

[0061] A method for preparing a titanium-cobalt-nickel composite nanosheet catalyst comprises the following steps:

[0062] 1) dissolving cobalt acetate in ethylene glycol and stirring for 2 hours to obtain an organic solution A, wherein the mass ratio of cobalt acetate to ethylene glycol is 1:15;

[0063] 2) dissolving nickel acetate in ethylene glycol and stirring for 3 hours to obtain an organic solution B, wherein the mass ratio of nickel acetate to ethylene glycol is 1:15;

[0064] 3) dissolving tetrabutyl titanate in ethylene glycol and stirring for 2 hours to obtain an organic solution C, wherein the mass ratio of tetrabutyl titanate to ethylene glycol is 1:10;

[0065] 4) Mixing organic solution A, organic solution B and organic solution C, and stirring for 2 hours to obtain a mixed organic solution D, wherein the molar ratio of cobalt, nickel and titanium elements after mixing is 0.3:0.7:1;

[0066] 5) placing the mixed organic solution D in a hydrothermal reactor for hydrothermal reaction at 150° C. for 7 h to obtain a reaction mixture D, which was allowed to stand until it reaches room temperature;

[0067] 6) After the reaction mixture E is clearly separated into layers, the liquid phase product on the top is removed, and the solid phase product on the bottom is placed in a muffle furnace and calcined at 800° C. for 8 hours;

[0068] 7) After the calcination reaction is completed, the reaction product F is directly placed on a steel plate for quenching, and the temperature of the steel plate is 0° C. and controlled by an ice-water mixture water bath to obtain the final titanium-cobalt-nickel composite nanosheet catalyst sample, and the thickness of the nanosheet is about 100 to 200 nm.

[0069] The titanium-cobalt-nickel composite nanosheet catalyst prepared in this example is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0070] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnet rotary stirring reactor, add a certain amount of catalyst at the same time, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct a wet oxidation experiment on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8MPa. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 36780mg / L, and the COD removal rate = (COD 反应前 -COD 反应后 )÷COD 反应前 ×100%.

[0071] Table 3 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0072]

[0073] The experimental results in Table 3 show that the addition of catalyst can greatly improve the treatment efficiency of wet oxidation, and the removal rate of pharmaceutical wastewater by catalytic wet oxidation increases with the increase of catalyst amount. When the reaction temperature is 160℃, the reaction time is 2.5h, and the catalyst addition amount is 0.3g / L, the removal rate of pharmaceutical wastewater by catalytic wet oxidation is 54.6%, which is 33.4% higher than the removal rate of the system without catalyst; when the reaction temperature is 160℃, the reaction time is 2.5h, the catalyst addition amount is increased to 0.6g / L, the COD removal rate is increased to 66.9%, which is 45.7% higher than the removal rate of the system with catalyst; when the reaction temperature is 160℃, the reaction time is 2.5h, and the catalyst addition amount is further increased to 1.4g / L, the removal rate of pharmaceutical wastewater by catalytic wet oxidation is 78.7%, which is 57.5% higher than the removal rate of the system without catalyst under similar conditions.

[0074] Example 4

[0075] The titanium-cobalt-nickel composite nanosheet catalyst prepared in Example 3 is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0076] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnet rotary stirring reactor, add a certain amount of catalyst at the same time, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct a wet oxidation experiment on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8MPa. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 38125mg / L, and the COD removal rate = (COD 反应前 -COD 反应后 )÷COD 反应前 ×100%.

[0077] Table 4 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0078]

[0079]

[0080] From the experimental results in Table 4, it can be seen that the removal efficiency of catalytic wet oxidation for pharmaceutical wastewater increases significantly after adding catalyst. When no catalyst is added, the reaction temperature is 180℃, the reaction time is 2.5h, and the COD removal rate of wastewater is 32.5%; when the catalyst addition amount is 0.2g / L, the reaction temperature is 180℃, and the reaction time is 2.5h, the COD removal rate increases significantly to 64.6%, which is 32.1% higher than the removal rate of the system without catalyst; when the reaction temperature is 180℃, the reaction time is 2.5h, the catalyst addition amount is increased to 0.9g / L, and the COD removal rate increases to 86.1%, which is 53.6% higher than the removal rate of the system with catalyst; when the reaction temperature is 180℃, the reaction time is 2.5h, and the catalyst addition amount is 1.5g / L, the efficiency of catalytic wet oxidation treatment of pharmaceutical wastewater is as high as 92.5%, which is 60% higher than when no catalyst is added.

[0081] Example 5

[0082] A method for preparing a titanium-cobalt-nickel composite nanosheet catalyst comprises the following steps:

[0083] 1) dissolving cobalt acetate in ethylene glycol and stirring for 2 hours to obtain an organic solution A, wherein the mass ratio of cobalt acetate to ethylene glycol is 1:20;

[0084] 2) dissolving nickel acetate in ethylene glycol and stirring for 3 hours to obtain an organic solution B, wherein the mass ratio of nickel acetate to ethylene glycol is 1:20;

[0085] 3) dissolving tetrabutyl titanate in ethylene glycol and stirring for 2 hours to obtain an organic solution C, wherein the mass ratio of tetrabutyl titanate to ethylene glycol is 1:12;

[0086] 4) Mixing solution A, solution B and solution C, and stirring for 2 hours to obtain a mixed organic solution D, wherein the molar ratio of cobalt, nickel and titanium elements after mixing is 0.4:0.6:1;

[0087] 5) placing the mixed organic solution D in a hydrothermal reactor for hydrothermal reaction at 160° C. for 8 h to obtain a reaction mixture E, which was allowed to stand until it reaches room temperature;

[0088] 6) After the reaction mixture E is clearly separated into layers, the liquid phase product on the top is removed, and the solid phase product on the bottom is placed in a muffle furnace and calcined at 850° C. for 7 hours;

[0089] 7) After the calcination reaction is completed, the reaction product F is directly placed on a steel plate for quenching, and the temperature of the steel plate is 0° C. and controlled by an ice-water mixture water bath to obtain the final titanium-cobalt-nickel composite nanosheet catalyst sample, and the thickness of the nanosheet is about 100 to 200 nm.

[0090] The titanium-cobalt-nickel composite nanosheet catalyst prepared in this example is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0091] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnetic rotary stirring reactor, add a certain amount of catalyst at the same time, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct wet oxidation experiments on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8Ma. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 39271mg / L, and the COD removal rate = (COD before reaction - COD after reaction) ÷ COD before reaction × 100%.

[0092] Table 5 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0093]

[0094] From the experimental results in Table 5, it can be seen that compared with the wet oxidation system without catalyst, the removal effect of catalytic wet oxidation for pharmaceutical wastewater is greatly improved after the catalyst is added. When no catalyst is added, the reaction temperature is 175℃, the reaction time is 2.5h, and the wastewater COD removal rate is 29.1%; when the catalyst addition amount is 0.4g / L, the reaction temperature is 175℃, and the reaction time is 2.5h, the wastewater COD removal rate is increased to 64.3%, which is 35.2% higher than when no catalyst is added; when the catalyst amount is increased to 0.9g / L, the efficiency of catalytic wet oxidation treatment of pharmaceutical wastewater is 80.4%, which is 51.3% higher than when no catalyst is added under similar conditions; when the catalyst amount is further increased to 1.6g / L, the COD removal rate is further increased to 89.1%, which is 60% higher than when no catalyst is added under similar conditions.

[0095] Example 6

[0096] The titanium-cobalt-nickel composite nanosheet catalyst prepared in Example 5 is used in the catalytic wet oxidation treatment of pharmaceutical wastewater. The specific procedure is as follows:

[0097] Add 0.5L of pharmaceutical wastewater to a 1.0L permanent magnetic rotary stirring reactor, add a certain amount of catalyst, seal the reactor after mixing, and set the reaction temperature. When the reaction temperature rises to the set temperature, start timing and conduct wet oxidation experiments on pharmaceutical wastewater. During the reaction, condensed water is used to cool the external accessories of the device, and oxygen is introduced into the reactor to maintain an oxygen partial pressure of 0.8MPa. After the wet oxidation reaction is completed, the device is naturally cooled to room temperature. Use a disposable syringe to take the supernatant in the reactor for filtration, and analyze the residual chemical oxygen demand (COD) in the wastewater sample. The initial COD concentration of pharmaceutical wastewater is 41,000mg / L, and the COD removal rate = (COD before reaction - COD after reaction) ÷ COD before reaction × 100%.

[0098] Table 6 Removal effect of catalytic wet oxidation on pharmaceutical wastewater under different reaction conditions

[0099]

[0100] From the experimental results in Table 6, it can be seen that compared with the wet oxidation system without catalyst, the addition of catalyst can greatly improve the catalytic wet oxidation treatment efficiency of pharmaceutical wastewater. After the catalyst is added, the COD removal rate of the wastewater is greatly improved, and it increases with the increase of the amount of catalyst. When no catalyst was added, the reaction temperature was 190℃, the reaction time was 2.5h, and the COD removal rate of the wastewater was 36.1%; when the amount of catalyst added was 0.3g / L, the reaction temperature was 190℃, and the reaction time was 2.5h, the COD removal rate of the wastewater catalytic wet oxidation was increased to 77.8%, an increase of 41.7% over the absence of catalyst; when the amount of catalyst was increased to 0.8g / L, the reaction temperature was 190℃, and the reaction time was 2.5h, the COD removal rate of the wastewater catalytic wet oxidation was further increased to 92.5%, an increase of 56.4% over the absence of catalyst; when the amount of catalyst added was 1.4g / L, the reaction temperature was 190℃, and the reaction time was 2.5h, the COD removal of the pharmaceutical wastewater catalytic wet oxidation was as high as 99.5%, an increase of 63.4% over the absence of catalyst. These experimental results show that the addition of catalyst can greatly promote the wet oxidation reaction of pharmaceutical wastewater and improve the wastewater treatment effect.

[0101] In summary, combined with Figures 1 to 6 It can be seen that in the method for preparing a titanium-cobalt-nickel composite nanosheet catalyst of the present invention, the characteristics of the catalyst are different due to different preparation process conditions.

[0102] Figure 1 The catalysts prepared in Examples 1 and 2 have a microscopic morphology showing a nanosheet structure, with a side length of about 1 μm-3 μm and a thickness of about 100 nm. Figure 2 The catalysts prepared in Examples 3 and 4 have a microscopic morphology showing a nanosheet structure, with a side length of about 500 nm to 5 μm and a thickness of about 100 to 200 nm; Figure 3 The catalysts prepared in Examples 5 and 6 have a microscopic morphology showing a nanosheet structure with a side length of about 1 μm to 4 μm and a thickness of about 100 nm.

[0103] Figure 4 The X-ray diffraction results of the catalyst samples prepared in Examples 1 and 2 show that the main diffraction peak positions (2θ / °) and crystal planes are: 24.1°(012), 32.7°(104), 35.2°(110), 40.6°(113), 49.1°(024), 53.7°(116), 62.1°(214) and 63.6°(300). Through data analysis, it can be concluded that the catalyst has an R-3 space group crystal structure, α=β=90°, γ=120°, a=b about c = approx.

[0104] Figure 5 The X-ray diffraction results of the catalyst samples prepared in Examples 3 and 4 show that the main diffraction peak positions (2θ / °) and crystal planes are: 24.03°(012), 32.9°(104), 35.6°(110), 40.6°(113), 49.4°(024), 53.9°(116), 62.5°(214) and 63.9°(300). Through data analysis, it can be concluded that the catalyst has an R-3 space group crystal structure, α=β=90°, γ=120°, a=b about c = approx.

[0105] Figure 6 The X-ray diffraction results of the catalyst samples prepared in Examples 5 and 6 are as follows; the main diffraction peak positions (2θ / °) and crystal planes are: 24.02°(012), 32.9°(104), 35.6°(110), 40.7°(113), 49.4°(024), 53.8°(116), 62.2°(214) and 63.8°(300). Through data analysis and processing, it can be concluded that the catalyst has an R-3 space group crystal structure, α=β=90°, γ=120°, a=b about c = approx.

[0106] Figure 7 The present invention is a process flow chart of the preparation process of the catalyst.

[0107] The invention discloses an application of a titanium-cobalt-nickel composite nanosheet catalyst in catalytic wet oxidation treatment of pharmaceutical wastewater. The prepared catalyst has a nanosheet structure and has a pollutant removal rate of up to 99%, and can efficiently and stably reduce the pollutant concentration in pharmaceutical wastewater.

[0108] The above examples are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. Application of a titanium-cobalt-nickel composite nanosheet catalyst in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: The preparation method of the titanium-cobalt-nickel composite nanosheet catalyst comprises the following steps: Step 1: dissolving cobalt acetate in ethylene glycol, stirring continuously, to obtain an organic solution A; Step 2: dissolving nickel acetate in ethylene glycol, stirring continuously, to obtain an organic solution B; Step 3: dissolving tetrabutyl titanate in ethylene glycol, stirring continuously, to obtain an organic solution C; Step 4: Mix the organic solution A, the organic solution B and the organic solution C, and continue stirring to obtain a mixed organic solution D; Step 5: placing the mixed organic solution D in a hydrothermal reactor for hydrothermal reaction to obtain a reaction mixture E, and allowing it to stand to room temperature; Step 6: After the reaction mixture E is clearly separated into layers, the liquid phase product on the top is removed, and the solid phase product on the bottom is burned for reaction; Step 7: After the calcination reaction, the reaction product F is placed on a steel plate for quenching to obtain the final titanium-cobalt-nickel composite nanosheet catalyst sample.

2. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: In step 1, the mass ratio of cobalt acetate to ethylene glycol is 1: 10-20.

3. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: In step 2, the mass ratio of nickel acetate to ethylene glycol is 1: 10-20.

4. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: In step 3, the mass ratio of tetrabutyl titanate to ethylene glycol is 1:7-12.

5. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: In step 4, the molar ratio of cobalt, nickel and titanium elements in the organic solution D is x:1-x:1, wherein 0.2≤x≤0.

4.

6. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: The temperature of the hydrothermal reaction in step 5 is 140-160°C, and the reaction time is 6-8 h.

7. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: The temperature of the calcination reaction in step 6 is 750-850° C., and the reaction time is 6-8 hours.

8. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: The temperature of the steel plate in step 7 is 0°C, which is controlled by an ice-water mixture water bath.

9. The use of the titanium-cobalt-nickel composite nanosheet catalyst according to claim 1 in catalytic wet oxidation treatment of pharmaceutical wastewater, characterized in that: The COD concentration of the pharmaceutical wastewater is 30,500 to 41,000 mg / L; the temperature of the catalytic wet oxidation reaction is 150°C to 190°C, the reaction time is 0.5 to 2.5 hours, and the amount of catalyst added is 0.20 to 1.60 g / L.

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