Oxygen-vacancy-enriched multi-metal attapulgite-based catalyst as well as preparation method and application thereof

Abstract

The invention discloses an oxygen-vacancy-enriched multi-metal attapulgite-based catalyst as well as a preparation method and application thereof, and belongs to the technical field of sewage treatment. The oxygen-vacancy-enriched multi-metal attapulgite-based catalyst is formed by taking attapulgite and activated carbon powder as matrixes and adopting two metal oxides containing oxygen vacancies for loading; the method is simple in preparation method, controllable in stoichiometry, simple in synthesis equipment and low in raw material cost, and the catalyst is used for removing pesticides in high-salt pesticide wastewater and has excellent salt resistance and efficient degradation activity.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater deep treatment and catalyst, and in particular to an oxygen-vacancy-rich multi-metal attapulgite-based catalyst and a preparation method and application thereof. Background Art

[0002] Pesticide wastewater is a typical salt-containing, difficult-to-degrade industrial wastewater, mainly produced by the production, use and cleaning of pesticide spraying equipment. Pesticide wastewater has the characteristics of high salinity, high COD, high toxicity, complex chemical composition and poor biodegradability. After secondary biochemical treatment, the effluent still contains residual pesticides, which poses a threat to the ecological environment and human health, and the demand for deep treatment is becoming increasingly urgent.

[0003] Heterogeneous catalytic ozone oxidation technology is an advanced oxidation technology that can produce active oxygen species such as hydroxyl radicals, thereby significantly improving ozone utilization and organic matter mineralization rate. The reaction conditions are mild, green and efficient, and there is no secondary pollution. It is suitable for the deep treatment of pesticide wastewater. In a typical heterogeneous catalytic ozone oxidation process, ozone is adsorbed on the catalyst and then decomposed to produce hydroxyl radicals and other free radicals to efficiently degrade organic pollutants. However, the high concentration of inorganic anions in pesticide wastewater will quench active oxygen species such as hydroxyl radicals in heterogeneous catalytic ozone oxidation, which will have a significant inhibitory effect on the oxidation efficiency.

[0004] Therefore, during the use of commonly used catalysts (especially those utilizing free radicals in metal oxides for catalysis, i.e., the oxidation reaction between free radicals and organic matter to effectively degrade organic pollutants), the high concentration of inorganic anions in the pesticide wastewater will quench the free radicals, thereby increasing the difficulty of achieving the oxidation reaction and significantly inhibiting the oxidation efficiency, thereby making it necessary to improve the catalytic effect in treating pesticide wastewater. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an oxygen-vacancy-rich multi-metal attapulgite-based catalyst and a preparation method and application thereof.

[0006] An oxygen-vacancies-rich multi-metal attapulgite-based catalyst, characterized in that the oxygen-vacancies-rich multi-metal attapulgite-based catalyst is formed by using attapulgite and activated carbon powder as a matrix and two metal oxides containing oxygen vacancies for loading, and the mass ratio of the attapulgite, activated carbon powder, and metal oxide containing oxygen vacancies is: 40-80:10-25:20-50; wherein the metal oxide containing oxygen vacancies includes copper oxide containing oxygen vacancies and cerium oxide containing oxygen vacancies;

[0007] The preparation method of the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies is:

[0008] S1-1, taking Cu(NO3)2·6H2O, Ce(NO3)3·6H2O, pure water, and a precipitant solution with a concentration of 2-5 mol / L according to a ratio of 8-16 g: 8-16 g: 1 L: 2 L, wherein the precipitant is sodium hydroxide or potassium hydroxide;

[0009] First, dissolve Cu(NO3)2·6H2O and Ce(NO3)3·6H2O in pure water, add the precipitant solution and stir after dissolution, then perform hydrothermal treatment at a temperature of 60 to 130° C. for 5 to 12 hours for precipitation, and obtain an oxygen-rich vacancy metal precursor after precipitation;

[0010] S1-2, drying and calcining the oxygen-vacancy-rich metal precursor obtained in S1-1 to obtain the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies.

[0011] Description: The above-mentioned catalyst obtained by using attapulgite and activated carbon powder as the matrix and copper oxide and cerium oxide containing oxygen vacancies as the carrier can utilize the advantages of higher specific surface area and porosity of attapulgite and activated carbon powder. At the same time, in the copper oxide and cerium oxide containing oxygen vacancies, the presence of oxygen vacancies can capture oxygen-containing species, thereby enhancing the catalyst's ability to adsorb ozone, so as to directly promote the dissociation of ozone into non-radical species such as surface atomic oxygen and singlet oxygen; copper oxide and cerium oxide have excellent catalytic activity, and the surfaces of both are rich in hydroxyl groups and oxygen vacancies, which are potential active sites for the generation of non-radical active species; therefore, it has a good treatment effect on high-salt pesticide wastewater.

[0012] Furthermore, in S1-2, the drying temperature is 60-130°C, and the drying time is 6-12 hours.

[0013] Note: The above temperature setting is more preferred. Exceeding this range may cause the surface properties of metal oxides containing oxygen vacancies to decrease.

[0014] Furthermore, in S1-2, the calcination is: placing the dried oxygen-rich vacancy metal precursor in a tubular furnace, calcining for 2 to 6 hours at a temperature of 300 to 600° C. in a reducing atmosphere to obtain a calcined solid, and grinding the calcined solid into 100 mesh to complete the treatment.

[0015] Note: The above calcination method can promote the formation of pores in the catalyst carrier through drying and calcination, increase the specific surface area, and provide more anchoring points for the active components, thereby improving the activity of the catalyst. The catalyst precursor may undergo a phase change to form a phase with specific catalytic properties. Calcination is carried out in a reducing atmosphere to adjust the redox state of the active components and optimize their catalytic performance.

[0016] Furthermore, the reducing atmosphere in S1-2 is pure H2 or a H2 / Ar2 mixed gas.

[0017] A method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst comprises the following steps:

[0018] S1. Mix attapulgite, metal oxide containing oxygen vacancies in activated carbon powder, and water in a mass ratio of 40-80:10-25:20-50:10-25 to obtain a mixture, and age the mixture for 2-6 hours to obtain a wet material;

[0019] S2, placing the wet material in a granulator for granulation, granulating to obtain a cylindrical material, and then extruding to obtain a molding material, and drying the molding material at a temperature of 110 to 130° C. for 5 to 7 hours to obtain a catalyst blank;

[0020] S3. The catalyst blank obtained in step S2 is placed in a reducing atmosphere and calcined at a temperature of 300-600° C. for 3-5 hours to obtain a calcined catalyst, and then the calcined catalyst is rinsed with deionized water until the pH of the rinse water is 7-8, and then dried at a temperature of 60-130° C. for 11-24 hours to obtain the oxygen-rich vacancy multi-metal attapulgite-based catalyst.

[0021] Description: Through the above-mentioned preparation method, attapulgite, activated carbon powder, copper oxide containing oxygen vacancies and cerium oxide containing oxygen vacancies can be combined and loaded, and catalyst particles with moderate size and good catalytic effect can be obtained through granulation. The binding effect of the dead can be further optimized through calcination, thereby improving the surface performance and catalytic activity of the catalyst.

[0022] Furthermore, the reducing atmosphere in S3 is pure Ar2 or a H2 / Ar2 mixed gas.

[0023] Note: The above-mentioned atmosphere is a reducing atmosphere, and calcination is carried out in a reducing atmosphere to adjust the redox state of the active components and optimize their catalytic performance.

[0024] Furthermore, the aging treatment is:

[0025] First, the mixture is placed in a constant temperature water bath at a temperature of 40-45°C for 1-2 hours, during which it is stirred every 30 minutes, and each stirring time is 2-4 minutes; then the mixture is transferred to an oven at a temperature of 60-65°C for 1-3 hours, during which it is stirred every 40 minutes, and each stirring time is 3-6 minutes; then the mixture is subjected to microwave treatment at a microwave power of 300 W for 10-60 minutes.

[0026] Description: Aging treatment can further improve the performance of materials, promote the rearrangement and optimization of the internal structure of materials, improve the chemical and physical stability of materials, enhance their durability and anti-aging properties, and at the same time increase their specific surface area and porosity, thereby enhancing catalytic activity and selectivity.

[0027] Furthermore, the microwave treatment is: intermittent microwave radiation is performed at a microwave frequency of 2450 MHz, the intermittent microwave radiation is irradiated for 30 seconds and rested for 30 seconds; and the frequency of each radiation is reduced by 50 MHz compared with the frequency of the previous radiation; and during the microwave radiation process, the material is stirred every 3 minutes.

[0028] Note: Through the above-mentioned microwave treatment, the microstructure of the material can be optimized, crystal growth and grain refinement can be promoted, the active sites on the surface of the material can be increased, and its chemical reactivity can be improved.

[0029] Furthermore, the oxygen-vacancy-rich multi-metal attapulgite-based catalyst is used to remove pesticides from high-salt pesticide wastewater (the salt content in high-salt pesticide wastewater is more than 1%, such as imidacloprid wastewater, fungicide wastewater, and herbicide wastewater).

[0030] Description: The catalyst obtained in the method of the present invention introduces oxygen vacancies through calcination in a reducing atmosphere and doping with activated carbon, generating potential active sites for non-radical active species, which can avoid the occurrence of active oxygen species such as hydroxyl radicals quenched by high concentrations of inorganic anions in pesticide wastewater in heterogeneous catalytic ozone oxidation. It has good salt resistance and high catalytic activity and is suitable for the treatment of high-salt pesticide wastewater.

[0031] The beneficial effects of the present invention are:

[0032] The present invention uses attapulgite and activated carbon powder as a matrix and copper oxide and cerium oxide containing oxygen vacancies as a carrier to obtain an oxygen-vacancy-rich multi-metal attapulgite-based catalyst, which can utilize the advantages of high specific surface area and porosity of attapulgite and activated carbon powder. At the same time, in the copper oxide and cerium oxide containing oxygen vacancies, the presence of oxygen vacancies can capture oxygen-containing species, thereby enhancing the catalyst's ability to adsorb ozone, so as to directly promote the dissociation of ozone into non-radical species such as surface atomic oxygen and singlet oxygen; copper oxide and cerium oxide have excellent catalytic activity, and the surfaces of both are rich in hydroxyl groups and oxygen vacancies, which are potential active sites for generating non-radical active species; therefore, it has a good treatment effect on high-salt pesticide wastewater; the preparation method of the present invention is simple, the stoichiometry is controllable, the synthesis equipment is simple, and the raw material cost is low; and the oxygen-vacancy-rich multi-metal attapulgite-based catalyst of the present invention has excellent salt resistance and efficient catalytic effect on the treatment of high-salt pesticide wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a diagram showing the removal effect of atrazine in Example 1-6;

[0034] Figure 2 is the solid electron spin resonance spectrum of the ozone catalyst prepared in Example 1-3;

[0035] Figure 3 This is the solid electron paramagnetic resonance spectrum of the ozone catalyst prepared in Example 1;

[0036] Figure 4 The COD-Cr removal effect diagram of Example 1 and Example 2;

[0037] Figure 5 It is a product schematic diagram of the molding material in Example 1. DETAILED DESCRIPTION

[0038] In order to further illustrate the method adopted by the present invention and the effect achieved, the technical solution of the present invention will be clearly and completely described in combination with experiments below.

[0039] In the embodiments of the present invention, oxygen vacancies, as an important anion defect, have been shown to significantly affect the catalytic performance of the catalyst. The presence of oxygen vacancies can capture oxygen-containing species, thereby enhancing the catalyst's ability to adsorb ozone. In addition, oxygen vacancies can also directly promote the dissociation of ozone into non-radical species such as surface atomic oxygen and singlet oxygen. Copper oxide and cerium oxide are common non-precious metal oxides, which are widely used as active components of catalysts because of their excellent catalytic activity. The surfaces of these two metal oxides are rich in hydroxyl groups and oxygen vacancies, which are potential active sites for generating non-radical active species. Based on this, an oxygen-vacancy-rich multi-metal concave soil-based salt-resistant catalyst was developed in order to achieve excellent salt resistance and efficient catalytic activity in the treatment of high-salt pesticide wastewater.

[0040] In recent years, non-radical oxidation processes have attracted extensive attention because they can produce high-concentration and long-lived reactive oxygen species. Compared with traditional free radical oxidation processes, non-radical oxidation processes show significant advantages in pesticide wastewater treatment: non-radical oxidizing species usually have good selectivity for bacteria and electron-rich organic matter; non-radical oxidation processes have strong resistance to water interference and are less affected by water pH and coexisting matrices (such as inorganic anions and natural organic matter); the utilization efficiency of oxidants in non-radical oxidation processes is higher, which helps to reduce the cost of water pollution control technology. Therefore, it is of great significance to develop ozone catalysts based on non-radical processes.

[0041] Embodiment 1: An oxygen-vacancy-rich multi-metal attapulgite-based catalyst, wherein the oxygen-vacancy-rich multi-metal attapulgite-based catalyst is formed by using attapulgite and activated carbon powder as a matrix and two metal oxides containing oxygen vacancies for loading, wherein the mass ratio of the attapulgite, activated carbon powder, and the two metal oxides containing oxygen vacancies is 45:15:30; wherein the two metal oxides containing oxygen vacancies include copper oxide containing oxygen vacancies and cerium oxide containing oxygen vacancies;

[0042] The preparation method of the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies is:

[0043] S1-1, taking Cu(NO3)2·6H2O, Ce(NO3)3·6H2O, pure water, and a precipitant solution with a concentration of 4 mol / L according to the ratio of 8g:16g:1L:2L, wherein the precipitant is sodium hydroxide;

[0044] First, Cu(NO3)2·6H2O and Ce(NO3)3·6H2O are dissolved in pure water, and after dissolution, the precipitant solution is added and stirred, and then hydrothermally treated at a temperature of 120° C. for 6 hours for precipitation, and after precipitation, an oxygen-rich vacancy metal precursor is obtained;

[0045] S1-2, drying and calcining the oxygen-rich vacancy metal precursor obtained in S1-1 to obtain the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies, the drying temperature is 120°C, and the drying time is 6 hours; the calcination is: placing the dried oxygen-rich vacancy metal precursor in a tube furnace, calcining for 4 hours at a temperature of 400°C and a reducing atmosphere to obtain a calcined solid, grinding the calcined solid to 100 mesh to complete the treatment; the reducing atmosphere is pure H2;

[0046] A method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst comprises the following steps:

[0047] S1. Mix attapulgite, activated carbon powder, metal oxide containing oxygen vacancies, and water in a mass ratio of 60:20:40:20 to obtain a mixture, and age the mixture for 4 hours to obtain a wet material;

[0048] S2, placing the wet material in a granulator for granulation, granulating to obtain a cylindrical material, and then extruding to obtain a molding material, and drying the molding material at a temperature of 120° C. for 6 hours to obtain a catalyst blank; the molding material is specifically as follows Figure 5 The butterfly shape shown;

[0049] S3. The catalyst blank obtained in step S2 is placed in a reducing atmosphere and calcined at 400° C. for 4 hours to obtain a calcined catalyst, and then the calcined catalyst is rinsed with deionized water until the pH of the rinse water is 7, and then dried at 120° C. for 12 hours to obtain the oxygen-rich vacancy multi-metal attapulgite-based catalyst; the reducing atmosphere is pure Ar2.

[0050] The aging treatment is as follows:

[0051] First, the mixture was placed in a constant temperature water bath at 42°C for 1.5 hours, during which it was stirred every 30 minutes, and each stirring time was 3 minutes; then the mixture was transferred to an oven at 63°C for 2 hours, during which it was stirred every 40 minutes, and each stirring time was 4 minutes; then the mixture was subjected to microwave treatment at a microwave power of 300 W for 30 minutes;

[0052] The microwave treatment comprises: intermittent microwave radiation at a microwave frequency of 2450 MHz, wherein the intermittent microwave radiation is irradiated for 30 seconds and rested for 30 seconds; and the frequency of each radiation is reduced by 50 MHz compared with the frequency of the previous radiation; and during the microwave radiation process, the material is stirred every 3 minutes.

[0053] Example 2: This example is different from Example 1 in that attapulgite, activated carbon powder, copper oxide containing oxygen vacancies obtained in S1-2, and cerium oxide containing oxygen vacancies are mixed in a mass ratio of 80:10:20.

[0054] Example 3: This example is different from Example 1 in that attapulgite, activated carbon powder, copper oxide containing oxygen vacancies obtained in S1-2, and cerium oxide containing oxygen vacancies are mixed in a mass ratio of 40:25:50.

[0055] Example 4: The difference between this example and Example 1 is that in S1-1, Cu(NO3)2·6H2O and Ce(NO3)3·6H2O are taken in a ratio of 8g:8g.

[0056] Example 5: The difference between this example and Example 1 is that in S1-1, Cu(NO3)2·6H2O and Ce(NO3)3·6H2O are taken in a ratio of 16g:8g.

[0057] Example 6: The difference between this example and Example 1 is that in S1-1, Cu(NO3)2·6H2O and Ce(NO3)3·6H2O are taken in a ratio of 16g:16g.

[0058] Example 7: This example is different from Example 1 in that the precipitant is potassium hydroxide.

[0059] Example 8: This example is different from Example 1 in that the concentration of the precipitant solution is 2 mol / L.

[0060] Example 9: This example is different from Example 1 in that the concentration of the precipitant solution is 5 mol / L.

[0061] Example 10: This example is different from Example 1 in that in S1-1, hydrothermal treatment is performed at 60°C for 5 hours for precipitation.

[0062] Example 11: This example is different from Example 1 in that in S1-1, hydrothermal treatment is performed at a temperature of 130°C for 12 hours for precipitation.

[0063] Example 12: The difference between this example and Example 1 is that the drying temperature in S1-2 is 60°C and the drying time is 6 hours; the calcination is: placing the dried oxygen-rich vacancy metal precursor in a tubular furnace, and calcining it for 6 hours at a temperature of 300°C and a reducing atmosphere; the reducing atmosphere is a mixture of H2 and Ar2 in a volume ratio of 1:1.

[0064] Example 13: The difference between this example and Example 1 is that the drying temperature in S1-2 is 130°C and the drying time is 12 hours; the calcination is: placing the dried oxygen-rich vacancy metal precursor in a tubular furnace and calcining it for 2 hours at a temperature of 600°C and a reducing atmosphere.

[0065] Example 14: This example is different from Example 1 in that the mass ratio of attapulgite, activated carbon powder, metal oxide containing oxygen vacancies, and water in S1 is 60:20:40:10 to obtain a mixture, and the mixture is aged for 6 hours to obtain a wet material.

[0066] Example 15: This example is different from Example 1 in that the mass ratio of attapulgite, activated carbon powder, metal oxide containing oxygen vacancies, and water in S1 is 60:20:40:25 to obtain a mixture, and the mixture is aged for 2 hours to obtain a wet material.

[0067] Example 16: This example is different from Example 1 in that in S2, the butterfly-shaped material is dried at a temperature of 110° C. for 7 hours to obtain a catalyst blank.

[0068] Example 17: This example is different from Example 1 in that in S2, the butterfly-shaped material is dried at a temperature of 130° C. for 5 hours to obtain a catalyst blank.

[0069] Example 18: The difference between this example and Example 1 is that in S3, the catalyst blank is placed in a reducing atmosphere and calcined at a temperature of 300°C for 3 hours to obtain a calcined catalyst, and then the calcined catalyst is rinsed with deionized water until the pH of the rinse water is 7, and then dried at a temperature of 60°C for 11 hours to obtain the oxygen-rich vacancy multi-metallic concave clay-based catalyst; the reducing atmosphere is a mixed gas of H2 / Ar2 in a volume ratio of 1:1.

[0070] Example 19: The difference between this example and Example 1 is that in S3, the catalyst blank is placed in a reducing atmosphere and calcined at a temperature of 600°C for 5 hours to obtain a calcined catalyst, and then the calcined catalyst is rinsed with deionized water until the pH of the rinse water is 8, and then dried at a temperature of 130°C for 24 hours to obtain the oxygen-rich vacancy multi-metal concave clay-based catalyst.

[0071] Example 20: This example is different from Example 1 in that the aging treatment is as follows: first, the mixture is placed in a constant temperature water bath at 40°C for 1 hour, during which it is stirred every 30 minutes, and each stirring time is 2 minutes; then, the mixture is transferred to an oven at 60°C for 1 hour, during which it is stirred every 40 minutes, and each stirring time is 3 minutes; then, the mixture is subjected to microwave treatment at a microwave power of 300 W for 10 minutes.

[0072] Example 21: This example is different from Example 1 in that the aging treatment is as follows: first, the mixture is placed in a constant temperature water bath at 45°C for 2 hours, during which it is stirred every 30 minutes, and each stirring time is 4 minutes; then, the mixture is transferred to an oven at 65°C for 3 hours, during which it is stirred every 40 minutes, and each stirring time is 6 minutes; then, the mixture is subjected to microwave treatment at a microwave power of 300 W for 60 minutes.

[0073] Experimental Example: The description of this experimental example is based on the scheme described in Example 1, and is intended to illustrate the practical application effect of the present invention.

[0074] Experimental Example: 1. The catalysts obtained in Examples 1 to 21 were subjected to the following tests:

[0075] 1. Catalytic ozone oxidation performance test:

[0076] The catalytic ozone oxidation performance test was carried out in an air-blowing tower in an intermittent mode. A high-salt atrazine solution and a catalyst were added to the reactor, and then ozone was introduced into the solution to start the reaction. During the catalytic ozone oxidation reaction, samples were drawn using a syringe, and samples were taken at 0 min, 2.5 min, 5 min, 10 min, 20 min, and 40 min, respectively. Sodium thiosulfate was quickly added to quench the reaction, and the atrazine concentration of the sample was detected by high-performance liquid chromatography on the same day.

[0077] In a typical catalytic ozone oxidation experiment, the catalyst dosage is 100 g / L, the ozone dosage is 200 mg / L·h, the atrazine concentration is 10 mg / L, the atrazine solution volume is 1 L, the chloride ion concentration is 10 g / L, the initial pH is adjusted to pH = 7 ± 0.1, the temperature is adjusted to T = (20 ± 0.5) ° C, and the reaction time is 40 min.

[0078] The test results are as follows:

[0079] 1. Explore the effects of different treatment methods on the performance of catalysts;

[0080] Comparative Example 1: The difference from Example 1 is that no activated carbon is added;

[0081] Comparative Example 2: The difference from Example 1 is that the aging step is not performed;

[0082] Comparative Example 3: The difference from Example 1 is that the copper oxide and the cerium oxide are not subjected to the treatments of S1-1 and S1-2, and the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies are replaced by copper oxide and cerium oxide;

[0083] Comparative Example 4: The difference from Example 1 is that iron oxide and manganese oxide containing oxygen vacancies are used to replace the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies in Example 1;

[0084] Comparative Example 5: The difference from Example 1 is that no microwave treatment is performed.

[0085] Example 1, Example 2 and Example 3, Example 15 and Example 16, and Comparative Examples 1 to 4 are compared, as shown in Table 1;

[0086] Table 1 Experimental results of the catalytic activity of atrazine by catalysts obtained in different ways

[0087] parameter 40min Atrazine removal rate % Example 1 91.3％ Comparative Example 1 67.6％ Comparative Example 2 69.3％ Comparative Example 3 63.5％ Comparative Example 4 74.7％ Comparative Example 5 70.1％

[0088] As can be seen from Table 1, by comparing Example 1 with Comparative Example 1, it can be seen that the preparation method in Example 1 is more preferred. Compared with Comparative Example 1, the activated carbon added to the matrix material of Example 1 provides a large number of active sites for the metal oxide containing oxygen vacancies, which helps to improve the activity and efficiency of the catalyst, and the pore structure of the activated carbon can promote the diffusion of reactants and products, reduce mass transfer resistance, and thus increase the rate of the catalytic reaction. Therefore, it is more preferred to add activated carbon to the raw materials of Example 1 of the present invention.

[0089] By comparing Example 1 with Comparative Example 2, it can be seen that compared with the step of not performing aging treatment in Comparative Example 2, since the aging treatment can further improve the performance of the material and promote the rearrangement and optimization of the internal structure of the material; Comparative Example 2 is not subjected to aging treatment, the catalytic activity and selectivity of the obtained catalyst are inferior to those in Example 1.

[0090] By comparing Example 1 with Comparative Example 3, it can be found that the selection of the metal oxide containing oxygen vacancies in Example 1 is more preferred. In Comparative Example 3, the metal oxide is directly used as a carrier for loading. Since the high concentration of inorganic anions in the pesticide wastewater will quench free radicals, thereby increasing the difficulty of achieving the oxidation reaction, the effect of using metal oxides for loading is very limited.

[0091] By comparing Example 1 with Comparative Example 4, it can be seen that iron oxide and manganese oxide are used in Comparative Example 4 instead of copper oxide containing oxygen vacancies and cerium oxide containing oxygen vacancies in Example 1. The results show that the choice of metal in Example 1 is more preferred. This may be because copper oxide and cerium oxide have excellent catalytic activity, and the surfaces of both are rich in hydroxyl groups and oxygen vacancies, which are potential active sites for generating non-radical active species; therefore, they have a good treatment effect on high-salt pesticide wastewater; and relatively speaking, the iron oxide and manganese oxide catalysts in Comparative Example 4 have a lower isoelectric point and their ability to catalyze the conversion of ozone into hydroxyl radicals is weak, so the effect of treating pesticide wastewater is not as good as Example 1.

[0092] By comparing Example 1 with Comparative Example 5, it can be seen that the catalytic effect of the catalyst obtained after microwave treatment in Example 1 is better than that of Comparative Example 5 which has not been subjected to microwave treatment. The reason may be that microwave treatment can optimize the microstructure of the material, promote crystal growth and grain refinement, increase the active sites on the surface of the material, and improve its chemical reactivity.

[0093] 2. To explore the effect of catalysts obtained with different preparation parameters on the catalytic activity of atrazine;

[0094] Example 1 and Examples 10-19 were compared, as shown in Table 2;

[0095] Table 2 Experimental results of atrazine catalysis by catalysts obtained with different preparation parameters

[0096]

[0097]

[0098] As can be seen from Table 2, by comparing Example 1, Example 10 and Example 11, it can be found that the hydrothermal treatment conditions of Example 1 are more preferred; this may be because, under the hydrothermal temperature, copper salt and cerium salt can be well precipitated, so that the structure of the obtained precipitate (metal hydroxide) is better, which is conducive to subsequent preparation and loading. By comparing Example 1, Example 12 and Example 13, it can be found that the drying and calcination parameters of Example 1 are more preferred, because drying and calcination can promote the formation of pores in the catalyst carrier, increase the specific surface area, provide more anchoring points for the active components, thereby improving the activity of the catalyst, and the catalyst precursor may undergo a phase change to form a phase with specific catalytic performance. Calcination can be carried out in a reducing atmosphere to adjust the redox state of the active components and optimize their catalytic performance. By comparing Example 1, Example 14 and Example 15, it can be found that the wet material preparation parameters of Example 1 are more preferred; by comparing Example 1, Example 16 and Example 17, it can be found that the drying parameters of Example 1 and the size of the obtained material are more appropriate; by comparing Example 1, Example 18 and Example 19, it can be found that the calcination parameters in Example 1 are more preferred.

[0099] 3. Explore the effect of raw material addition amount on the catalytic performance of the obtained catalyst;

[0100] Figure 1 The present invention's embodiments 1-4 and comparative examples 1-2 are shown, and a control example (ozone catalysis alone in the figure) in which a catalyst is added and only ozone catalysis is used is also provided. The effects of ozone oxidation of atrazine by ozone catalysts prepared in embodiments 1-4, comparative examples 1-2 and the control example are shown. Figure 1 As shown, the removal rates of atrazine by catalysts 1-4 (corresponding to catalysts 1-4 in the figure) with oxygen vacancies were all greater than 75% within 40 minutes, which was much higher than that of ozone oxidation alone. Among them, the best removal rate was obtained by the catalyst of Example 1, with a removal rate of 96.2% for atrazine in 40 minutes.

[0101] Figure 2 The solid electron spin resonance spectra of the ozone catalysts prepared in Examples 1-3 of the present invention are shown. Figure 2As shown, Example 1 (implementation catalyst 1 in the figure), Comparative Example 1 (comparative catalyst 1 in the figure) and Comparative Example 2 (comparative catalyst 2 in the figure) have asymmetric electron spin resonance signals at g=2.003, indicating that oxygen vacancy defects exist on the surfaces of the three catalysts. Compared with Comparative Example 2, the electron spin resonance signals of Example 1 and Comparative Example 1 are more significant, indicating that the hydrothermal synthesis and reducing atmosphere calcination process significantly increase the concentration of Vo on the surface of copper oxide and cerium oxide, and the modification of activated carbon further enhances this process.

[0102] Figure 3 The electron paramagnetic resonance spectrum of the oxygen vacancy-rich multi-metal attapulgite-based catalyst prepared in Example 1 of the present invention during the treatment of atrazine (pesticide herbicide) is shown. Figure 3 As shown in the figure, in the process of ozone oxidation of atrazine alone, the spectra of hydroxyl adducts, superoxide radical adducts and singlet oxygen adducts did not show obvious characteristic peaks, which indicated that the degradation of atrazine was mainly achieved through the direct oxidation mechanism of ozone. In the process of catalytic ozone oxidation of atrazine using catalyst 1, clear characteristic peaks of hydroxyl adducts with a signal intensity of 1:2:2:1, superoxide radical adducts with a signal intensity of 1:1:1:1 and singlet oxygen adducts with a signal intensity of 1:1:1 were observed, indicating that the catalytic ozone oxidation process using catalyst 1 produced three active oxygen species: hydroxyl radicals, superoxide radicals and singlet oxygen.

[0103] Figure 4 The COD removal rate of the actual high-salt pesticide wastewater treated by the oxygen-vacancy multi-metal attapulgite-based salt-resistant catalyst prepared in Examples 1 and 2 of the present invention is shown. Figure 4 As shown, after 60 minutes of reaction, the COD removal rate of high-salinity pesticide wastewater treated by catalytic ozone oxidation in Comparative Example 1 reached 50.7%, which is much higher than that of single ozonation treatment, while the catalytic ozone oxidation system in Example 1 further improved the treatment effect of high-salinity pesticide wastewater, with a COD removal rate of 69.8%. The results show that the oxygen-vacancy-rich multi-metal attapulgite-based catalyst has great potential in the catalytic ozone oxidation treatment of actual high-salinity organic wastewater.

Claims

1. An oxygen-vacancy-rich multi-metal attapulgite-based catalyst, characterized in that: The oxygen-vacancies-rich multi-metal attapulgite-based catalyst is formed by using attapulgite and activated carbon powder as a matrix and using a metal oxide containing oxygen vacancies for loading, wherein the mass ratio of the attapulgite, activated carbon powder, and metal oxide containing oxygen vacancies is 40-80:10-25:20-50; wherein the metal oxide containing oxygen vacancies includes copper oxide containing oxygen vacancies and cerium oxide containing oxygen vacancies; The preparation method of the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies is: S1-1, taking Cu(NO3)2·6H2O, Ce(NO3)3·6H2O, pure water, and a precipitant solution with a concentration of 2-5 mol / L according to a ratio of 8-16 g: 8-16 g: 1 L: 2 L, wherein the precipitant is sodium hydroxide or potassium hydroxide; First, dissolve Cu(NO3)2·6H2O and Ce(NO3)3·6H2O in pure water, add the precipitant solution and stir after dissolution, then perform hydrothermal treatment at a temperature of 60 to 130° C. for 5 to 12 hours for precipitation, and obtain an oxygen-rich vacancy metal precursor after precipitation; S1-2, drying and calcining the oxygen-vacancy-rich metal precursor obtained in S1-1 to obtain the copper oxide containing oxygen vacancies and the cerium oxide containing oxygen vacancies.

2. The oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 1, characterized in that: In S1-2, the drying temperature is 60-130°C, and the drying time is 6-12 hours.

3. The oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 1, characterized in that: In S1-2, the calcination is as follows: placing the dried oxygen-rich vacancy metal precursor in a tubular furnace, calcining for 2 to 6 hours at a temperature of 300 to 600° C. in a reducing atmosphere to obtain a calcined solid, and grinding the calcined solid to 100 mesh to complete the treatment.

4. The oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 3, characterized in that: The reducing atmosphere described in S1-2 is pure H2 or a H2 / Ar2 mixed gas.

5. The method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 1, characterized in that: The following steps are involved: S1. Mix attapulgite, activated carbon powder, metal oxide containing oxygen vacancies, and water in a mass ratio of 40-80:10-25:20-50:10-25 to obtain a mixture, and age the mixture for 2-6 hours to obtain a wet material; S2, placing the wet material in a granulator for granulation, granulating to obtain a cylindrical material, and then extruding to obtain a molding material, and drying the molding material at a temperature of 110 to 130° C. for 5 to 7 hours to obtain a catalyst blank; S3. The catalyst blank obtained in step S2 is placed in a reducing atmosphere and calcined at a temperature of 300-600° C. for 3-5 hours to obtain a calcined catalyst, and then the calcined catalyst is rinsed with deionized water until the pH of the rinse water is 7-8, and then dried at a temperature of 60-130° C. for 11-24 hours to obtain the oxygen-rich vacancy multi-metal attapulgite-based catalyst.

6. The method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 5, characterized in that: The reducing atmosphere in S3 is pure Ar2 or a H2 / Ar2 mixed gas.

7. The method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 5, characterized in that: The aging treatment is as follows: First, the mixture is placed in a constant temperature water bath at a temperature of 40-45°C for 1-2 hours, during which it is stirred every 30 minutes, and each stirring time is 2-4 minutes; then the mixture is transferred to an oven at a temperature of 60-65°C for 1-3 hours, during which it is stirred every 40 minutes, and each stirring time is 3-6 minutes; then the mixture is subjected to microwave treatment at a microwave power of 300 W for 10-60 minutes.

8. The method for preparing an oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 5, characterized in that: The microwave treatment comprises: intermittent microwave radiation at a microwave frequency of 2450 MHz, wherein the intermittent microwave radiation is irradiated for 30 seconds and rested for 30 seconds; and the frequency of each radiation is reduced by 50 MHz compared with the frequency of the previous radiation; and during the microwave radiation process, the material is stirred every 3 minutes.

9. The use of an oxygen-vacancy-rich multi-metal attapulgite-based catalyst according to claim 1, characterized in that: The method is applied to remove pesticides from the high-salt pesticide wastewater, which is pesticide-containing wastewater with a salt content of more than 1%.

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