A composite ceramic catalytic membrane of cobalt copper layered double hydroxide and silicon carbide

Abstract

The present application relates to a kind of cobalt copper layered double hydroxide and silicon carbide composite ceramic catalytic membrane, belong to membrane water treatment technical field.The present application uses suction filtration-calcination process, cobalt copper layered double hydroxide nanosheet is vacuum suction filtered to the surface of silicon carbide porous ceramic membrane, calcination in reducing atmosphere, i.e., CoCu-LDH / SiC composite ceramic catalytic membrane is obtained, including SiC porous ceramic membrane and CoCu-LDH catalyst supported on the surface of ceramic membrane.The present application makes CoCu-LDH catalyst and SiC ceramic membrane have strong combination, while giving catalyst more defects and metal active site, and then improve the activation of persulfate and the degradation of organic pollutants.The CoCu-LDH / SiC composite ceramic catalytic membrane prepared by the present application has simple preparation process, low firing temperature, low cost, catalyst and ceramic membrane are combined closely, suitable for industrial production and water treatment application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of membrane water treatment, more specifically, relates to a CoCu-LDH / SiC composite ceramic catalytic membrane, and particularly to a CoCu-LDH / SiC composite ceramic catalytic membrane, a preparation method and application thereof. BACKGROUND

[0002] Sulfonamide antibiotics (SAs) are a class of synthetic antibacterial drugs, belonging to nitrogen-containing heterocyclic compounds, which are not easily destroyed by metabolic processes and can exist stably in the environment for a long time, posing a great risk to the environment and human health.

[0003] Common methods for removing SAs include biological methods, adsorption methods, chlorination methods, advanced oxidation methods, and membrane separation methods. Biological methods have low operating costs and mild reaction conditions, but strong adsorbents (such as microplastics) in water bodies can affect antibiotic removal; adsorption methods are simple to operate, have high removal efficiency, low energy consumption, no by-products, and are renewable, but SAs are only separated and transferred from water, and have not been degraded, and still need further treatment; chlorination methods can effectively remove SAs, but the removal process is greatly affected by pH, and toxic by-products such as chloroform and chlorite are produced, causing secondary pollution problems; membrane separation methods have strong process adaptability, simple separation devices, and easy operation, but are prone to membrane fouling; advanced oxidation methods include ozone oxidation, Fenton oxidation, photochemical oxidation, electrochemical oxidation, and persulfate oxidation, among which the persulfate oxidation method has many advantages, such as a wide pH adaptation range, easy transportation and storage, and has attracted widespread attention from scholars, but the transition metal catalyst activated persulfate has the problems of easy loss and difficulty in recovery during water treatment.

[0004] To solve the above problems, the coupling process combining membrane separation technology and persulfate advanced oxidation has great application potential, especially the combination of ceramic membranes and catalysts to form ceramic catalytic membranes, which not only solves the problem of easy aging of organic membranes during use, but also can be used in extreme conditions such as strong acid and alkali. The patent "Preparation method of high-flux visible light responsive nanowire catalytic ceramic membrane" (CN 114471511A) discloses a method for preparing a visible light responsive nanowire catalytic ceramic membrane by loading titanium dioxide nanowires on a ceramic membrane; the patent "Nitrogen-doped metal carbon-based composite ceramic catalytic membrane and preparation method and application thereof" (CN 115608403 A) discloses a method for preparing a ceramic catalytic membrane by loading MOF material-derived nitrogen-doped metals on the surface and inside of a ceramic membrane; however, the above inventions have problems such as insufficient utilization of transition metal active sites in heterogeneous persulfate oxidation systems, complicated preparation process, and low catalyst loading strength.

[0005] Therefore, it is urgent to find a catalytic material that can sufficiently improve the utilization rate of transition metal active sites. Layered double hydroxides (LDH) have unique layered structure, anion exchangeability and guest molecule adjustability, and exhibit excellent reaction activity in activating persulfate, and are widely concerned in the catalytic advanced oxidation coupling process. SUMMARY

[0006] The application selects CoCu-LDH nanosheet with excellent catalytic performance as a catalytic material, and loads it on the surface of SiC porous ceramic membrane through a filtration calcination method to form a CoCu-LDH / SiC composite ceramic catalytic membrane. The CoCu-LDH / SiC composite ceramic catalytic membrane not only has higher catalytic performance, but also can realize efficient activation of persulfate and rapid degradation of sulfamethoxazole, and overcomes the problem of catalyst collection after application. In addition, compared with other ceramic catalytic membranes, the CoCu-LDH / SiC composite ceramic catalytic membrane has lower preparation cost.

[0007] According to a first aspect of the application, a preparation method of a composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide is provided, which comprises the following steps:

[0008] (1) mixing silicon carbide and polyvinyl alcohol solution to obtain a blank; dry-pressing the blank into a block-shaped material, drying the block-shaped material, and then calcining to obtain a silicon carbide porous ceramic support;

[0009] (2) adding silicon carbide and polyvinyl alcohol into water, mixing to obtain a silicon carbide ceramic slurry; coating the silicon carbide ceramic slurry on the surface of the silicon carbide porous ceramic support obtained in step (1), drying, and then calcining to obtain a silicon carbide porous ceramic membrane;

[0010] (3) dispersing cobalt-copper layered double hydroxide nanosheets to obtain a suspension, and using a vacuum filtration method to filter the suspension onto the surface of the silicon carbide porous ceramic membrane obtained in step (2), drying, and then calcining in a reducing atmosphere to obtain the composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide.

[0011] Preferably, in step (3), the calcination temperature is 300-500℃, the temperature rising rate is 3-10℃ / min, and the holding time is 1-3h.

[0012] Preferably, the cobalt-copper layered double hydroxide nanosheets account for 0.02%-0.1% of the mass of the silicon carbide porous ceramic membrane.

[0013] Preferably, in step (3), the cobalt-copper layered double hydroxide nanosheet is prepared by the following method: Co(NO3)2 and Cu(NO3)2 are added to water, and then Na2CO3 is added to obtain a mixed solution, the pH value of the mixed solution is adjusted to 8-11, the mixed solution is filtered to obtain a precipitate, and the precipitate is washed and dried to obtain the cobalt-copper layered double hydroxide nanosheet.

[0014] Preferably, the molar ratio of Co(NO3)2 to Cu(NO3)2 is (2-4):1.

[0015] Preferably, the molar ratio of Na2CO3 to the sum of the molar amounts of cobalt ions and copper ions is 1:(1-3).

[0016] Preferably, in step (1), the calcination temperature is 1000-1200℃, and the holding time is 2-4h.

[0017] In step (2), the calcination temperature is 900-1100℃, and the holding time is 2-4h.

[0018] According to another aspect of the present application, there is provided a composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide prepared by any one of the methods.

[0019] Preferably, the loading amount of the cobalt-copper layered double hydroxide nanosheet in the composite ceramic catalytic membrane is 0.16-0.80mg / cm 2 .

[0020] According to another aspect of the present application, the composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide is used for catalyzing the degradation of wastewater containing organic pollutants by persulfate.

[0021] Preferably, the organic pollutants are one or more of antibiotics, dyes, and humic acid.

[0022] Preferably, the pH of the wastewater containing organic pollutants is 3-10.

[0023] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0024] (1) The present application uses SiC as a raw material to prepare a silicon carbide porous ceramic membrane, uses the silicon dioxide formed by surface oxidation during the sintering process of SiC for bonding, and the sintering temperature is only 1000-1200 DEG C, compared with the ceramic membranes prepared from commonly used raw materials such as alumina, zirconia and titania, the sintering temperature of the SiC porous ceramic membrane is relatively low, so the preparation cost of the ceramic membrane can be greatly reduced, thereby being suitable for large-scale industrial production and application. The CoCu-LDH / SiC composite ceramic catalytic membrane prepared in the present application has the advantages of simple preparation process, low sintering temperature and low cost, and the catalyst and the ceramic membrane are combined closely.

[0025] (2) The present application loads CoCu-LDH nanosheets on the surface of the ceramic membrane in situ through a filtration-calcination process, and calcination is carried out under H2 atmosphere, which not only enhances the bonding force between the catalyst and the ceramic membrane, but also improves the defect concentration of the CoCu-LDH nanosheets, so that the ceramic catalytic membrane has excellent catalytic stability and high catalytic degradation efficiency for sulfamethoxazole, and can realize instantaneous filtration catalytic degradation of sulfamethoxazole in wastewater, with a degradation rate of more than 91%.

[0026] (3) The present application can control the loading amount of CoCu-LDH nanosheets on the surface of the SiC porous ceramic membrane by controlling the concentration of the nanosheet solution according to the pollutant concentration in the actual wastewater, so as to prepare CoCu-LDH / SiC composite ceramic catalytic membranes with different catalytic effects, realize the synergistic optimization of the driving pressure, flux, catalytic efficiency and preparation cost of the ceramic catalytic membrane, and greatly expand the economic designability of the ceramic catalytic membrane for catalytic degradation of pollutants in wastewater.

[0027] (4) The present application adopts the filtration-calcination process, so that the CoCu-LDH catalyst and the SiC ceramic membrane have strong combination, and the catalyst has more defects and metal active sites, thereby improving the activation of persulfate and the degradation of organic pollutants.

[0028] (5) The CoCu-LDH / SiC composite ceramic catalytic membrane prepared in the present application has high degradation efficiency (the degradation rate of sulfamethoxazole is more than 91%), wide pH adaptation range (pH=3-10), and can be applied in complex water environments. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is the physical map (a) and the micro-morphology map (b) of the CoCu-LDH / SiC composite ceramic catalytic membrane in Example 1.

[0030] Figure 2 It is the treatment effect diagram of the CoCu-LDH / SiC composite ceramic catalytic membrane on sulfamethoxazole under different concentrations of persulfate in Example 2.

[0031] Figure 3 Figure of the treatment effect of CoCu-LDH / SiC composite ceramic catalytic membrane on sulfamethoxazole at different pH values in Example 3. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0033] The present application is a CoCu-LDH / SiC composite ceramic catalytic membrane and a preparation method thereof, comprising the following steps:

[0034] (1) Preparation of SiC porous ceramic support

[0035] First, SiC and polyvinyl alcohol (PVA) solution are poured into a zirconium oxide ball mill jar, and a planetary ball mill is used for ball milling mixing, the ball milling time is 60-120 min, and a uniform blank is obtained; then, the mixed blank is pressed into a block by a dry pressing forming process, the pressure is 30-50 MPa, then the blocky sample is placed in a blast drying oven for drying for 24-48 h, and finally, it is placed in a muffle furnace for calcination at 1000-1200℃, and the holding time is 2-4 h.

[0036] The average particle size of the silicon carbide is 10-38 μm;

[0037] The PVA has a molecular weight of 1700-5000 and a solution concentration of 2-6 wt%;

[0038] The addition amount of the PVA solution is 10-15 wt% of SiC.

[0039] (2) Preparation of SiC porous ceramic membrane

[0040] SiC, PVA and water are mixed in a certain proportion, stirred by a magnetic stirrer at 80-90℃ for 8-12 h to obtain a uniform SiC ceramic slurry, which is coated on the surface of the SiC porous ceramic support by an immersion coating method, the immersion time is 10-20 s, then dried in a blast drying oven at 25-30℃ for 12-24 h, and finally calcined in a muffle furnace to obtain a SiC porous ceramic membrane, the calcination temperature is 900-1100℃, and the holding time is 2-4 h.

[0041] The SiC particle size is 1-2 μm;

[0042] The PVA has a molecular weight of 10000-30000 and a concentration of 8-12wt%;

[0043] The SiC, PVA and water are in a mass ratio of 1:1:3-1:1:5.

[0044] (3) Preparation of CoCu-LDH nanosheets

[0045] A certain amount of Co(NO3)2·6H2O and Cu(NO3)2·3H2O is weighed and added to a reagent bottle containing deionized water. After magnetic stirring at 50-80℃ for 30-60min, Na2CO3 is added in a molar ratio of Na2CO3:(Co 2 + +Cu 2+ ) = 1:1, and the pH value of the solution is adjusted to 8-11 by NaOH and H2SO4. After continuing to stir for a period of time, CoCu-LDH nanosheets are obtained through filtration, washing, drying and other processes.

[0046] (4) Preparation of CoCu-LDH / SiC composite ceramic catalytic membrane

[0047] The prepared CoCu-LDH nanosheets are added to deionized water and ultrasonically dispersed for 1-3h to obtain a CoCu-LDH nanosheet suspension. The suspension is vacuum-filtered onto the surface of a SiC porous ceramic membrane using a vacuum filtration method, and the filtration time is 0.5-1h. Then, the obtained sample is placed in an oven at 80-110℃ for drying for 12-24h. Finally, the dried sample is placed in a tube furnace for calcination to obtain a CoCu-LDH / SiC composite ceramic catalytic membrane.

[0048] In some embodiments, the molar ratio of Co(NO3)2·6H2O to Cu(NO3)2·9H2O in step (3) is 4:1-2:1, and the total amount of addition is 4-8wt% of deionized water.

[0049] In some embodiments, the stirring rate in step (3) is 300-600rpm / min, and the stirring time is 48-72h.

[0050] In some embodiments, the loading amount of CoCu-LDH nanosheets in step (4) is 0.16-0.80mg / cm 2 .

[0051] In some embodiments, the calcination atmosphere in step (4) is a mixed gas of H2 and Ar, and H2 accounts for 5-15% of the total gas volume.

[0052] In some embodiments, the calcination temperature in step (4) is 300-500 DEG C, the heating rate is 3-10 DEG C / min, and the holding time is 1-3 h.

[0053] The CoCu-LDH / SiC composite ceramic catalytic membrane prepared in the application is used for catalyzing the degradation of one or more of antibiotics, dyes, and humic acid by persulfate.

[0054] In some embodiments, the antibiotic is sulfamethoxazole, and the concentration thereof is 2-10 mg / L.

[0055] In some embodiments, the persulfate is peroxymonosulfate, and the concentration thereof is 0.2-1 mM.

[0056] In some embodiments, the CoCu-LDH / SiC composite ceramic catalytic membrane has strong acid-base adaptability and can be applied in an environment with a pH of 3-10.

[0057] The following are specific embodiments

[0058] Embodiment 1

[0059] Step (1): Preparation of SiC porous ceramic support

[0060] First, 10 g of SiC with an average particle size of 38 μm and 1.5 g of polyvinyl alcohol (PVA) solution (concentration of 6 wt%) were poured into a zirconia ball mill jar, and a planetary ball mill was used for mixing by ball milling for 60 min to obtain a uniform blank; then the mixed blank was pressed into a block under a pressure of 30 MPa, and then the block-shaped sample was dried in a blast drying oven for 48 h; finally, it was placed in a muffle furnace for calcination at 1200 DEG C for 4 h to obtain a SiC porous ceramic support.

[0061] Step (2): Preparation of SiC porous ceramic membrane

[0062] 1-2 μm SiC, PVA solution (concentration of 12 wt%) and water were mixed in a mass ratio of 1:1:5, and a uniform SiC ceramic slurry was obtained by stirring at 90 DEG C for 12 h by a magnetic stirrer; the SiC porous ceramic support was coated with the slurry by an impregnation coating method, the impregnation time was 10 s, and then it was dried in a blast drying oven at 25 DEG C for 12 h; finally, it was placed in a muffle furnace for calcination to obtain a SiC porous ceramic membrane (as shown in FIG. 1), the calcination temperature was 1100 DEG C, and the holding time was 4 h. Figure 1

[0063] Step (3): Preparation of CoCu-LDH nanosheet

[0064] ​First, 2.0954 g of Co(NO3)2·6H2O and 0.4339 g of Cu(NO3)2·3H2O were weighed and added to a reagent bottle containing 40 ml of deionized water. After being stirred magnetically at 80°C for 60 min, Na2CO3 was added in a molar ratio of Na2CO3:(Co 2+ + Cu 2+ ) = 1:1, and the pH value of the solution was adjusted to 11 by NaOH and H2SO4. After continuing to stir for 72 h, CoCu-LDH nanosheets were obtained through filtration, washing, drying, and the like.

[0065] Step (4): Preparation of CoCu-LDH / SiC composite ceramic catalytic membrane

[0066] 8 mg of CoCu-LDH nanosheets were weighed and added to deionized water, and ultrasonic dispersion was performed for 1 h to obtain a CoCu-LDH nanosheet suspension. The suspension was filtered onto the surface of a SiC porous ceramic membrane by vacuum filtration for 0.5 h. Then, the obtained sample was placed in an oven at 80°C for drying for 12 h. Finally, the dried sample was placed in a tube furnace for calcination to obtain a CoCu-LDH / SiC composite ceramic catalytic membrane. The calcination atmosphere was a mixed gas of H2 and methane, the H2 concentration was 10%, the calcination temperature was 500°C, the heating rate was 5°C / min, and the holding time was 3 h.

[0067] The prepared CoCu-LDH / SiC composite ceramic catalytic membrane was used for performance testing of catalytic persulfate degradation of sulfamethoxazole in water. The results were as follows: under the conditions of a pressure of 1 bar, a pH of 5.722, a persulfate concentration of 0.2 mM, and a sulfamethoxazole concentration of 10 mg / L, the degradation rate of sulfamethoxazole was 94.89%.

[0068] Figure 1 Figure (a) and micro-morphology figure (b) of the CoCu-LDH / SiC composite ceramic catalytic membrane in Example 1. As can be seen from (a) in Figure Figure 1 , the CoCu-LDH catalyst was uniformly loaded on the surface of the SiC ceramic membrane. As can be seen from (b) in Figure Figure 1 , the coating thickness of the CoCu-LDH catalyst was 2.43 μm.

[0069] Example 2

[0070] Step (1): Preparation of SiC porous ceramic support

[0071] First, 10 g of SiC with an average particle size of 10 pm and 1 g of a polyvinyl alcohol (PVA) solution (concentration of 2 wt%) were poured into a zirconia ball mill jar, and mixed by a planetary ball mill, with a ball milling time of 120 min to obtain a uniform green body. Then, the mixed green body was pressed into a block under a pressure of 50 MPa, and then the block-shaped sample was dried in a blast drying oven for 24 h. Finally, the sample was calcined in a muffle furnace at 1000 °C for 2 h to obtain a SiC porous ceramic support.

[0072] Step (2): Preparation of a SiC porous ceramic membrane

[0073] SiC, a PVA solution (concentration of 8 wt%) and water were mixed in a mass ratio of 1:1:3, and stirred by a magnetic stirrer at 90 °C for 8 h to obtain a uniform SiC ceramic slurry. The slurry was coated on the surface of the SiC porous ceramic support by a dip-coating method, with a dipping time of 20 s. Then, the sample was dried in a blast drying oven at 30 °C for 24 h. Finally, the sample was calcined in a muffle furnace to obtain a SiC porous ceramic membrane (as shown in FIG. 1), with a calcination temperature of 900 °C and a holding time of 2 h. Figure 1

[0074] Step (3): Preparation of CoCu-LDH nanosheets

[0075] First, 1.7462 g of Co(NO3)2·6H2O and 0.7232 g of Cu(NO3)2·3H2O were weighed and added to a reagent bottle containing 40 ml of deionized water. After magnetic stirring at 80 °C for 30 min, Na2CO3 was added in a molar ratio of Na2CO3:(Co 2+ + Cu 2+ ) = 1:1, and the pH value of the solution was adjusted to 8 by NaOH and H2SO4. After continuous stirring for 48 h, CoCu-LDH nanosheets were obtained through filtration, washing and drying processes.

[0076] Step (4): Preparation of a CoCu-LDH / SiC composite ceramic catalytic membrane

[0077] 8 mg of CoCu-LDH nanosheets were weighed and added to deionized water, and ultrasonic dispersion was performed for 1 h to obtain a CoCu-LDH nanosheet suspension. The suspension was filtered onto the surface of the SiC porous ceramic membrane by vacuum suction filtration, with a filtration time of 0.5 h. Then, the obtained sample was dried in an oven at 80 °C for 12 h. Finally, the dried sample was calcined in a tube furnace to obtain a CoCu-LDH / SiC composite ceramic catalytic membrane, with a calcination atmosphere of a mixture of H2 and methane, a H2 concentration of 10%, a calcination temperature of 500 °C, a heating rate of 5 °C / min and a holding time of 3 h. ​

[0078] The prepared CoCu-LDH / SiC composite ceramic catalytic membrane was used for catalytic peroxymonosulfate degradation of sulfamethoxazole in water, and the performance test results are shown in Figure 2 As shown in the figure, under the conditions of 1 bar pressure, pH 5.722, peroxymonosulfate concentration of 0.2 mM, 0.5 mM, 1 mM, and sulfamethoxazole concentration of 10 mg / L, the degradation rate of sulfamethoxazole was 94.89%, 98.10%, and 99.59%, respectively.

[0079] Example 3

[0080] Step (1): Preparation of SiC porous ceramic support

[0081] First, 10 g of SiC with an average particle size of 25 μm and 1.2 g of polyvinyl alcohol (PVA) solution (concentration of 5 wt%) were poured into a zirconium oxide ball mill jar, and the mixture was ball milled using a planetary ball mill for 120 min to obtain a uniform blank. Then the mixed blank was pressed into a block under a pressure of 40 MPa, and then the block-shaped sample was dried in a forced air drying oven for 36 h. Finally, it was placed in a muffle furnace for calcination at 1100°C for 3 h to obtain the SiC porous ceramic support.

[0082] Step (2): Preparation of SiC porous ceramic membrane

[0083] 1-2 μm SiC, PVA solution (concentration of 10 wt%) and water were mixed in a mass ratio of 1:1:4, and the mixture was stirred by a magnetic stirrer at 90°C for 10 h to obtain a uniform SiC ceramic slurry. The slurry was coated on the surface of the SiC porous ceramic support by dip coating method, and the dipping time was 20 s. Then it was dried in a forced air drying oven at 30°C for 24 h. Finally, it was placed in a muffle furnace for calcination to obtain the SiC porous ceramic membrane (as shown in Figure 1 ), and the calcination temperature was 1000°C and the holding time was 3 h.

[0084] Step (3): Preparation of CoCu-LDH nanosheets

[0085] First, 2.0954 g of Co(NO3)2·6H2O and 0.4339 g of Cu(NO3)2·3H2O were weighed and added to a reagent bottle containing 40 ml of deionized water. After magnetic stirring at 80°C for 30 min, Na2CO3 was added in a molar ratio of Na2CO3:(Co 2+ + Cu 2+ ) = 1:1, and the pH value of the solution was adjusted to 8 by NaOH and H2SO4. After continuous stirring for 48 h, the CoCu-LDH nanosheets were obtained through filtration, washing, and drying processes.

[0086] Step (4): Preparation of CoCu-LDH / SiC composite ceramic catalytic membrane

[0087] 8 mg of CoCu-LDH nanosheets were weighed into deionized water and ultrasonically dispersed for 0.5 h to obtain a CoCu-LDH nanosheet suspension. The suspension was vacuum-filtered onto the surface of the SiC porous ceramic membrane for 0.5 h. Then, the obtained sample was placed in an oven at 90°C for drying for 18 h. Finally, the dried sample was placed in a tube furnace for calcination to obtain a CoCu-LDH / SiC composite ceramic catalytic membrane. The calcination atmosphere was a mixture of H2 and methane, the H2 concentration was 5%, the calcination temperature was 400°C, the heating rate was 3°C / min, and the holding time was 2 h.

[0088] The prepared CoCu-LDH / SiC composite ceramic catalytic membrane was used for performance testing of catalytic persulfate degradation of sulfamethoxazole in water, as shown in Table 1, the results were as follows: under the conditions of a pressure of 1 bar, a pH of 3.002, 5.236, 7.028, 9.063, 10.985, a persulfate concentration of 0.2 mM, and a sulfamethoxazole concentration of 10 mg / L, the degradation rate of sulfamethoxazole was 90.27%, 97.62%, 96.82%, 94.02%, and 89.85%, respectively. Figure 3

[0089] It is easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.​

Claims

1. Use of a composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide for the catalytic degradation of wastewater containing organic pollutants by persulfates, characterized in that, The persulfate is peroxymonosulfate, and the concentration of the peroxymonosulfate is 0.2-1 mM. The composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide is prepared by the following steps: (1) mixing silicon carbide and polyvinyl alcohol solution to obtain a blank; drying and calcining the blank to obtain a silicon carbide porous ceramic support; (2) adding silicon carbide and polyvinyl alcohol into water, mixing to obtain a silicon carbide ceramic slurry; coating the silicon carbide ceramic slurry on the surface of the silicon carbide porous ceramic support obtained in step (1), drying and calcining to obtain a silicon carbide porous ceramic membrane; (3) dispersing cobalt-copper layered double hydroxide nanosheets to obtain a suspension; vacuum filtering the suspension onto the surface of the silicon carbide porous ceramic membrane obtained in step (2), drying and calcining in a reducing atmosphere, the calcining temperature is 300-500 ℃, and the reducing atmosphere is a mixed gas of hydrogen and methane, thereby obtaining the composite ceramic catalytic membrane of cobalt-copper layered double hydroxide and silicon carbide.

2. Use according to claim 1, wherein The organic pollutants are one or more of antibiotics, dyes and humic acid.

3. Use according to claim 1 or 2, characterized in that, The pH of the wastewater containing organic pollutants is 3-10.

4. The use according to claim 1, wherein In step (3), the heating rate of calcination is 3-10 ℃ / min, and the holding time is 1-3 h.

5. The use according to claim 1, wherein In step (3), the mass fraction of the cobalt-copper layered double hydroxide nanosheets in the silicon carbide porous ceramic membrane is 0.02%-0.1%.

6. The use according to claim 1, wherein In step (3), the cobalt-copper layered double hydroxide nanosheets are prepared by the following method: adding Co(NO3)2 and Cu(NO3)2 into water, then adding Na2CO3 to obtain a mixed solution, adjusting the pH of the mixed solution to 8-11, filtering the mixed solution to obtain a precipitate, and washing and drying the precipitate to obtain the cobalt-copper layered double hydroxide nanosheets.

7. Use according to claim 6, wherein The molar ratio of Co(NO3)2 to Cu(NO3)2 is (2-4):

1.

8. The use according to claim 1, wherein The molar ratio of Na2CO3 to the sum of the molar amounts of cobalt ions and copper ions is 1:(1-3).

9. The use according to claim 1, wherein In step (1), the calcination temperature is 1000-1200 ℃, and the holding time is 2-4 h; In step (2), the calcination temperature is 900-1100 ℃, and the holding time is 2-4 h.

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