Oxidation catalysts, their preparation methods and applications

Abstract

This invention relates to the field of catalysts, specifically to an oxidation catalyst, its preparation method, and its application. An oxidation catalyst is characterized in that it comprises a support and an active component, wherein the active component comprises rare earth metal oxides and alkaline earth metal oxides; the catalyst comprises channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm. The active component of the oxidation catalyst of this invention comprises rare earth metal oxides and alkaline earth metal oxides, and the catalyst comprises channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm, resulting in mild operating conditions, high selectivity for small molecule organic compounds (acetic acid), and good stability.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to an oxidation catalyst, its preparation method, and its application. Background Technology

[0002] Wet oxidation is a technology developed in the 1950s for treating organic wastewater. This method involves oxidizing organic pollutants into inorganic substances such as CO2 and water, or small-molecule organic compounds, in a liquid phase under high temperature (125-320℃) and high pressure (0.5-20MPa) conditions, using air or pure oxygen as the oxidant. This process is energy-saving and environmentally friendly, and can treat toxic, harmful, and high-concentration organic wastewater.

[0003] In the carbon conversion process of oxidizing organic pollutants into CO2 or small-molecule organic matter, the former increases CO2 emissions into the atmosphere, while the latter does not effectively address the problem of organic pollutants in water. Therefore, it is hoped that new technologies can be developed to achieve carbon reuse, solve carbon emission problems, and mitigate the greenhouse effect.

[0004] In wet oxidation processes, while adding catalysts can improve efficiency and reduce reaction conditions, achieving high COD removal rates still requires high-temperature and high-pressure conditions. Furthermore, the support and active components are prone to loss under harsh reaction conditions, leading to a gradual decrease in COD removal efficiency over long periods of operation. When COD removal efficiency is relatively low, the main organic matter in the wastewater consists of small-molecule compounds, commonly small-molecule acids such as acetic acid. The presence of acetic acid affects the hydrothermal stability of the catalyst, and the corrosion of steel equipment and instruments increases exponentially with rising temperature. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of harsh reaction conditions, unstable catalysts, easy loss of active components, and low COD removal efficiency in the existing wet oxidation technology for treating organic wastewater. This invention provides an oxidation catalyst, its preparation method, and its application. This oxidation catalyst has the advantages of mild operating conditions, high selectivity for small molecule organic compounds (acetic acid), and good stability.

[0006] To achieve the above objectives, a first aspect of the present invention provides an oxidation catalyst comprising a support and an active component, wherein the active component comprises rare earth metal oxides and alkaline earth metal oxides; the catalyst comprises channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm.

[0007] The second aspect of the present invention provides a method for preparing an oxidation catalyst, the method comprising: (1) preparing a precursor containing a support, a rare earth metal and an alkali metal; (2) treating the precursor with acetic acid, washing, drying and shaping.

[0008] A third aspect of the present invention provides a catalyst prepared by the preparation method described in the second aspect of the present invention.

[0009] The fourth aspect of the present invention provides the application of the catalyst described in the first aspect and the catalyst described in the third aspect in catalytic wet oxidation.

[0010] The fifth aspect of the present invention provides a method for treating organic wastewater, the method comprising: reacting a salt-forming aid, organic wastewater and an oxidant in the presence of a catalyst, optionally recycling part of the material after the reaction back into the organic wastewater, and subjecting the remaining part to post-treatment; wherein the catalyst is the catalyst described in the first aspect and the catalyst described in the third aspect.

[0011] Through the above technical solution, the present invention has the following beneficial effects:

[0012] The active components of the oxidation catalyst of the present invention include rare earth metal oxides and alkaline earth metal oxides, and the catalyst includes channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm, which makes the catalyst have mild operating conditions, high selectivity for small molecule organic compounds (acetic acid), and good stability.

[0013] The catalyst of this invention is applied to catalytic wet oxidation technology with the goal of generating economically viable small molecule organic compounds (acetic acid). Carbon is selectively converted into small molecule organic compounds (acetic acid), which react with absorbed salt-forming aids to generate salt, thereby achieving carbon recycling and reducing carbon emissions. In a preferred embodiment, the salt-forming aid contains ammonia, which enables the recovery and utilization of ammonia. Attached Figure Description

[0014] Figure 1 This is a flow chart of an organic wastewater treatment process according to a preferred embodiment of the present invention;

[0015] Figure 2 This is a pore volume-pore size distribution diagram of the catalyst prepared in Example 1 of the present invention.

[0016] Explanation of reference numerals in the attached figures

[0017] 1. Absorption tower; 6. Gas phase stream;

[0018] 2. Oxidation reactor; 7. Absorbent solution;

[0019] 3. Distillation column; 8. Partial absorbent;

[0020] 4. Gas streams containing water-soluble organic matter; 9. Distillation condensate;

[0021] 5. Salt-forming aids; 10. Organic acid salts. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The present invention provides an oxidation catalyst comprising a support and an active component, wherein the active component comprises rare earth metal oxides and alkaline earth metal oxides; the catalyst comprises channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm.

[0024] The active components of the oxidation catalyst of the present invention include rare earth metal oxides and alkaline earth metal oxides, and the catalyst includes channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm, which makes the catalyst have mild operating conditions, high selectivity for small molecule organic compounds (acetic acid), and good stability.

[0025] According to a preferred embodiment of the present invention, the catalyst contains 30-60% pores with a pore size of 10-50 nm and 15-40% pores with a pore size of 1-2 nm, based on pore volume. For example, the catalyst contains 40%, 45%, 50%, 55%, and 60% pores with a pore size of 10-50 nm, and 15%, 20%, 25%, 30%, 35%, and 40% pores with a pore size of 1-2 nm.

[0026] According to a preferred embodiment of the present invention, the support comprises nano-metal oxides coated on the outer surface of the catalyst. By employing the aforementioned preferred embodiment, the stability of the catalyst can be further improved.

[0027] In this invention, there are no special requirements for the particle size of the nano-metal oxide. According to a preferred embodiment of this invention, the particle size of the nano-metal oxide is 2-10 nanometers.

[0028] In this invention, the type of nano-metal oxide can be a conventional choice in the art. According to a preferred embodiment of the invention, the nano-metal oxide is a nano-group IVB metal oxide, preferably selected from nano-titanium oxide and / or nano-zirconia, and more preferably nano-titanium oxide. By adopting the aforementioned preferred embodiment, the stability of the catalyst can be further improved.

[0029] In this invention, there are no particular limitations on the content of each component in the catalyst. According to a preferred embodiment of the invention, the catalyst comprises, based on 100 parts by weight: (1) 0.01-10 parts of alkaline earth metal oxide; (2) 0.1-2 parts of rare earth metal oxide; and (3) 88-99.89 parts of support. By adopting the aforementioned preferred embodiment, the selectivity of the catalyst for small molecule organic compounds (acetic acid) and the stability of the catalyst can be further improved.

[0030] In this invention, the carrier can be a conventional choice in the art. According to a preferred embodiment of the invention, the carrier is at least one of titanium oxide, zirconium oxide, and silicon oxide.

[0031] According to a preferred embodiment of the present invention, the support is a mixture of titanium oxide, zirconium oxide, and silicon oxide, preferably in a weight ratio of 50-70:8-45:10-25. By adopting the aforementioned preferred embodiment, the selectivity of the catalyst for small molecule organic compounds (acetic acid) and the stability of the catalyst can be further improved.

[0032] In this invention, the alkaline earth metal can be a conventional choice in the art. According to a preferred embodiment of the invention, the alkaline earth metal is selected from at least one of magnesium, calcium, strontium, and barium, preferably at least one of magnesium, calcium, and barium, and more preferably barium. By adopting the aforementioned preferred embodiment, the selectivity of the catalyst for small molecule organic compounds (acetic acid) and the stability of the catalyst can be further improved.

[0033] In this invention, the rare earth metal can be a conventional choice in the art. According to a preferred embodiment of the invention, the rare earth metal is selected from at least one of cerium, lanthanum, and neodymium. By employing the aforementioned preferred embodiment, the selectivity of the catalyst for small molecule organic compounds (acetic acid) and the stability of the catalyst can be further improved.

[0034] This invention provides a method for preparing an oxidation catalyst, the method comprising:

[0035] ((1) Preparation of precursors containing a support, rare earth metals and alkali metals;

[0036] (2) The precursor is treated with acetic acid, washed, dried and shaped.

[0037] The active components of the oxidation catalyst prepared by the method of the present invention include rare earth metal oxides and alkaline earth metal oxides, and the catalyst includes channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm, which makes the catalyst have mild operating conditions, high selectivity for small molecule organic compounds (acetic acid), and good stability.

[0038] According to a preferred embodiment of the present invention, step (1) includes: dissolving a carrier source, a rare earth metal source, and an alkaline earth metal source to obtain a mixed solution, adding an alkaline solution to the mixed solution to obtain a slurry, and subjecting the slurry to a first drying and a first calcination to obtain a precursor.

[0039] In this invention, no special requirements are made for the conditions of the first roasting. In this embodiment, roasting at 550°C for 2 hours is used as an example to illustrate the advantages of this invention.

[0040] According to a preferred embodiment of the present invention, in step (1), an alkaline solution is added to obtain a slurry with a pH of 8-10.

[0041] The range of carrier sources in this invention is relatively wide. For example, the carrier source can be silica sol, titanate TiOSO4, Zr(NO3)4, etc.

[0042] In this invention, the rare earth metal source is selected from soluble salts of cerium, lanthanum and neodymium, and the alkaline earth metal source is selected from soluble salts of magnesium, calcium, strontium and barium, with soluble salts of barium being more preferred.

[0043] According to a preferred embodiment of the present invention, the alkaline solution is selected from at least one of ammonia water, urea solution, sodium hydroxide solution, sodium carbonate solution and sodium bicarbonate solution.

[0044] According to a preferred embodiment of the present invention, the first drying method is spray drying.

[0045] According to a preferred embodiment of the present invention, the acetic acid treatment is carried out by hydrothermal treatment in an autoclave.

[0046] According to a preferred embodiment of the present invention, the conditions for acetic acid treatment in step (2) include: an acetic acid concentration of 0.1-2 wt%.

[0047] According to a preferred embodiment of the present invention, the conditions for acetic acid treatment in step (2) include: a temperature of 80-200°C, preferably 100-150°C.

[0048] According to a preferred embodiment of the present invention, the conditions for acetic acid treatment in step (2) include: a time of 5-120 min, preferably 15-60 min.

[0049] By employing the aforementioned acetic acid treatment conditions, the selectivity of the prepared catalyst for small molecule organic compounds (acetic acid) and the catalyst stability can be further improved.

[0050] According to a preferred embodiment of the present invention, the forming step in step (2) includes: bonding the dried solid, nano-metal oxide and binder, extruding, second drying and second calcination.

[0051] According to a preferred embodiment of the present invention, the mass ratio of the dried solid to the nano-metal oxide is 80-95:5-20, and the amount of binder is 2-30% of the total amount of the dried solid, nano-metal oxide and binder.

[0052] According to a preferred embodiment of the present invention, the particle size of the nano-metal oxide is 2-10 nanometers.

[0053] According to a preferred embodiment of the present invention, the nano-metal oxide is a Group IVB metal oxide, preferably selected from nano-titanium oxide and / or zirconium oxide, and more preferably nano-titanium oxide.

[0054] According to a preferred embodiment of the present invention, the binder is selected from at least one of water, liquid paraffin, hydroxymethyl cellulose, polyvinyl alcohol, starch and dextrin, and at least one of nitric acid, sulfuric acid, oxalic acid and citric acid.

[0055] In this invention, there are no special requirements for the second drying conditions. In the embodiments, drying at a temperature of 120°C is used as an example for illustration.

[0056] In this invention, there are no special requirements for the conditions of the second roasting. In the embodiments, roasting at a temperature of 550°C is used as an example for illustration.

[0057] This invention provides a catalyst prepared by the preparation method described herein.

[0058] This invention provides an application of the catalyst described herein in catalytic wet oxidation.

[0059] The catalyst of this invention is applied to catalytic wet oxidation technology with the goal of generating economically viable small molecule organic compounds (acetic acid). Carbon is selectively converted into small molecule organic compounds (acetic acid), which react with absorbed salt-forming aids to generate salt, thereby achieving carbon recycling and reducing carbon emissions.

[0060] This invention provides a method for treating organic wastewater, comprising: reacting a salt-forming aid, organic wastewater, and an oxidant in the presence of a catalyst; optionally, after the reaction, part of the material is recycled back into the organic wastewater, and the remainder is subjected to post-treatment; the catalyst is the catalyst described in this invention.

[0061] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the pH value of the material after the contact reaction is 2-6.5, preferably 4-6.5.

[0062] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the acetic acid concentration of the material after the contact reaction is 3-20 wt%, preferably 3-12 wt%.

[0063] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the COD value of the organic wastewater is 40,000-250,000 mg / L, preferably 40,000-150,000 mg / L.

[0064] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the salt-forming substance comprises at least one of ammonia, sodium hydroxide, and potassium hydroxide, preferably ammonia; more preferably, the molar ratio of ammonia to organic wastewater, based on the N / C ratio, is 1.6-2.5, preferably 1.8-2.2. By adopting the aforementioned preferred scheme, the salt-forming aid contains ammonia, enabling the recovery and utilization of ammonia. The advantages of the present invention are illustrated using ammonia as an example in this embodiment.

[0065] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the oxidant is an oxygen-containing gas, such as air, pure oxygen, or 35-50% oxygen-enriched gas.

[0066] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the volume ratio of oxygen to organic wastewater in the contact reaction system is 10-400.

[0067] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the reaction temperature is 250-300°C.

[0068] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: the reaction pressure is 7-12.0 MPa.

[0069] According to a preferred embodiment of the present invention, the conditions for the contact reaction include: a reaction time of 10-150 minutes, preferably 10-120 minutes.

[0070] According to a preferred embodiment of the present invention, the post-processing includes distillation crystallization and / or cooling crystallization.

[0071] like Figure 1 As shown, the present invention provides an organic wastewater treatment device, which includes an absorption tower 1, an oxidation reactor 2, and a distillation tower 3 connected in series. The absorption tower is provided with an inlet for a gas stream containing water-soluble organic matter 4, an inlet for a salt-forming agent 5, an outlet for a gaseous stream 6, an outlet for an absorbent liquid 7, an inlet for a distillation condensate 9, and an inlet for a circulating absorbent liquid. The oxidation reactor 2 is provided with an inlet for an absorbent liquid 7, an outlet for a partially absorbed liquid 8, and an outlet for a circulating absorbent liquid. The distillation tower is provided with an inlet for a partially absorbed liquid, an outlet for a distillation condensate 9, and an outlet for an organic acid salt 10.

[0072] The following will be explained through examples (in Figure 1The invention will be described in detail below (using the apparatus shown). In the following examples, the ammonia-containing gas is the reaction gas obtained after the laboratory ammoxidation reaction of propylene, and the oxidant used in the wet oxidation reaction is pure oxygen. Unless otherwise specified, all raw materials are commercially available.

[0073] The process diagram is a cyclic process. The key point is that the organic matter is converted into acetic acid in the wet oxidation reactor 2. Therefore, the examples only illustrate the catalyst and evaluation results.

[0074] Example 1

[0075] 1. Catalyst Preparation

[0076] (1) Spray drying: A mixture A is prepared by stirring together an aqueous solution containing 500g silica sol (40%), 230g Ba(NO3)2, 1800g Zr(NO3)4, and 41g La(NO3)3, and an aqueous solution containing 2350g TiOSO4. Under vigorous stirring in a water bath at 20-80℃, an ammonia solution is slowly added dropwise to solution A, controlling the final pH of the solution to 9.0, to obtain slurry B. Slurry B is then spray-dried to obtain powder C.

[0077] (2) Carrier pretreatment: Powder C was calcined at 550℃ for 2h (to obtain the precursor), then treated in a 0.5% acetic acid aqueous solution in an autoclave at 150℃ for 30 minutes, cooled and washed with water, and dried at 120℃ to obtain powder D;

[0078] (3) Molding: First, 180g of nano-TiO2 powder with a particle size of 2-10 nm is dispersed in a mixture of 130g of hydroxymethyl cellulose, 200g of nitric acid, and 500g of water. Then, it is bonded with powder D in a bonding machine, and after extrusion, drying at 120℃, and calcination at 550℃, the wet oxidation catalyst is obtained. The specific surface area and porosity are determined by a fully automated BET specific surface area and porosity analyzer, as shown below. Figure 2 The pore volume-pore size distribution diagram shown indicates that the catalyst includes channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm, wherein the content of channels with a pore size of 10-50 nm is 48% and the content of channels with a pore size of 1-2 nm is 22%.

[0079] 2. Catalyst Evaluation

[0080] Reaction conditions: temperature 280℃, pressure 7.5MPa, residence time 45min, oxygen / liquid volume ratio 300.

[0081] The reaction product was then sent for distillation and crystallization to obtain acetate.

[0082] The results are shown in Table 1.

[0083] Example 2

[0084] Similar to Example 1, except that in step (2), the powder C was calcined at 550°C for 2 hours (to obtain the precursor) and then treated in a 2% acetic acid aqueous solution in an autoclave at 120°C for 30 minutes, cooled, washed with water, and dried at 120°C to obtain powder D.

[0085] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 53%, and the content of pores with a diameter of 1-2 nm is 25%.

[0086] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0087] Example 3

[0088] Same as Example 1, except that in step (1), 41gLa(NO3)3 is replaced with 40gCe(NO3)3.

[0089] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 48%, and the content of pores with a diameter of 1-2 nm is 25%.

[0090] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0091] Example 4

[0092] Same as Example 1, except that in step (1), 41gLa(NO3)3 is replaced with 35gLa(NO3)3.

[0093] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 51%, and the content of pores with a diameter of 1-2 nm is 20%.

[0094] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0095] Example 5

[0096] Same as Example 1, except that step (1) pulping and spraying: an aqueous solution containing 250g silica sol (40%), 230g Ba(NO3)2, 1950g Zr(NO3)4, 41g La(NO3)3 and 2150g TiOSO 4的 Aqueous solutions were stirred to obtain solution A. Under vigorous stirring in a water bath at 20-80℃, ammonia solution was slowly added dropwise to solution A, controlling the final pH of the solution to 9.0, to obtain slurry B. Slurry B was then spray-dried to obtain powder C.

[0097] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 41%, and the content of pores with a diameter of 1-2 nm is 26%.

[0098] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0099] Example 6

[0100] Similar to Example 1, except that in step (1) slurry spraying: A mixture A containing 230g Ba(NO3)2 and 41g La(NO3)3 aqueous solution and 4080g TiOSO4 aqueous solution is stirred and mixed to obtain a mixture A. Under vigorous stirring in a water bath at 20-80℃, an ammonia solution is slowly added dropwise to solution A, controlling the final pH of the solution to be 9.0, to obtain slurry B. Slurry B is then spray-dried to obtain powder C.

[0101] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of channels with a pore size of 10-50 nm is 39%, and the content of channels with a pore size of 1-2 nm is 33%.

[0102] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0103] Example 7

[0104] Same as Example 1, except that in step (1), 230g Ba(NO3)2 is replaced with 440g Mg(NO3)2.

[0105] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 45%, and the content of pores with a diameter of 1-2 nm is 21%.

[0106] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0107] Example 8

[0108] Similar to Example 1, except that in step (3) molding: first, 260g of nano ZrO2 powder is dispersed in a mixture of 130g of hydroxymethyl cellulose, 200g of nitric acid and 500g of water, and then powder D is bonded in a bonding machine, and the wet oxidation catalyst is obtained by extrusion, drying at 120°C and calcination at 550°C.

[0109] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of pores with a diameter of 10-50 nm is 44%, and the content of pores with a diameter of 1-2 nm is 26%.

[0110] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0111] Example 9

[0112] Same as Example 1, except that step (3) molding: powder D is bonded in a bonding machine with a mixture of 130g hydroxymethyl cellulose, 200g nitric acid and 500g water, and then extruded, dried at 120°C and calcined at 550°C to obtain the wet oxidation catalyst.

[0113] The pore volume-pore size distribution of the obtained catalyst is compared with Figure 2 Similarly, the content of channels with a pore size of 10-50 nm is 51%, and the content of channels with a pore size of 1-2 nm is 28%.

[0114] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0115] Comparative Example 1

[0116] Same as Example 1, except that in step (2) carrier pretreatment: powder C is calcined at 550℃ for 2h to obtain powder D.

[0117] The content of pores with a diameter of 10-50 nm was less than 5%, as determined by the fully automated BET surface area and porosity analyzer.

[0118] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0119] Comparative Example 2

[0120] Same as Example 1, except that in step (2) carrier pretreatment: powder C is calcined at 550°C for 2 hours (to obtain the precursor), then treated in a 0.5% nitric acid aqueous solution in an autoclave at 150°C for 30 minutes, cooled, washed with water, and dried at 120°C to obtain powder D.

[0121] The content of pores with a diameter of 10-50 nm was less than 5%, as determined by the fully automated BET surface area and porosity analyzer.

[0122] The evaluation method is the same as in Example 1, and the results are shown in Table 1.

[0123] Table 1

[0124]

[0125] *1g of acetate is equivalent to 1.0667g of COD

[0126] *Selective calculation: Acetate contribution to COD / (Acetate contribution to COD + Converted COD) * 100%

[0127] Example calculation illustration for Example 1: 37441 / (37441+(55000-39300))*100%=69.9%

[0128] *Raw water description: The COD varies depending on the absorption time of the propylene ammonia oxidation reaction gas obtained by absorbing pure water.

[0129] *Effective conversion rate calculation: (Acetate contribution COD + Converted COD) / Raw water COD * 100%

[0130] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An oxidation catalyst, characterized in that, The catalyst comprises a support and an active component, wherein the active component comprises rare earth metal oxides and alkaline earth metal oxides; the catalyst comprises channels with a pore size of 1-2 nm and channels with a pore size of 10-50 nm. The method for preparing the catalyst includes: (1) Preparation of precursors containing a support, rare earth metals and alkali metals; (2) The precursor is treated with acetic acid, washed, dried and shaped; The acetic acid treatment method is hydrothermal.

2. The oxidation catalyst according to claim 1, wherein, The catalyst contains 30-60% pores with a pore size of 10-50 nm and 15-40% pores with a pore size of 1-2 nm; and / or The support comprises nano-metal oxides coated on the outer surface of the catalyst.

3. The oxidation catalyst according to claim 2, wherein, The particle size of the nano-metal oxide is 2-10 nanometers.

4. The oxidation catalyst according to claim 2, wherein, The nano-metal oxide is a nano-group IVB metal oxide.

5. The oxidation catalyst according to claim 2, wherein, The nano-metal oxide is selected from nano-titanium oxide and / or nano-zirconium oxide.

6. The oxidation catalyst according to claim 1, wherein, The catalyst comprises, based on 100 parts by weight: (1) 0.01-10 parts of alkaline earth metal oxides; (2) 0.1-2 parts of rare earth metal oxides; (3) 88-99.89 copies of the carrier.

7. The oxidation catalyst according to claim 1, wherein, The carrier is at least one of titanium dioxide, zirconium oxide, and silicon oxide; and / or The alkaline earth metal is selected from at least one of magnesium, calcium, strontium, and barium; and / or The rare earth metal is selected from at least one of cerium, lanthanum, and neodymium.

8. The oxidation catalyst according to claim 7, wherein, The carrier is a mixture of titanium dioxide, zirconium oxide, and silicon dioxide; and / or The alkaline earth metal is at least one of magnesium, calcium, and barium.

9. The oxidation catalyst according to claim 8, wherein, The mixture contains titanium oxide, zirconium oxide, and silicon oxide in a weight ratio of 50-70:8-45:10-25; and / or The alkaline earth metal is barium.

10. The oxidation catalyst according to claim 1, wherein, Step (1) includes: dissolving the carrier source, rare earth metal source and alkaline earth metal source to obtain a mixed solution, adding an alkaline solution to the mixed solution to obtain a slurry, and subjecting the slurry to a first drying and a first calcination to obtain a precursor; and / or The conditions for acetic acid treatment in step (2) include: Acetic acid concentration is 0.1-2 wt%; and / or Temperature is 80-200℃; and / or The time is 5-120 minutes; and / or The forming steps in step (2) include: bonding the dried solid, nano-metal oxide and binder, extruding, second drying, and second calcination.

11. The oxidation catalyst according to claim 10, wherein, Adding an alkaline solution yields a slurry with a pH of 8-10. and / or The conditions for acetic acid treatment in step (2) include: The temperature is 100-150℃; and / or The time is 15-60 minutes.

12. The oxidation catalyst according to claim 10, wherein, The mass ratio of the dried solid to the nano-metal oxide is 80-95:5-20, and the amount of binder added accounts for 2-30% of the total amount of the dried solid, nano-metal oxide, and binder; and / or The particle size of the nano-metal oxide is 2-10 nanometers; and / or The nano-metal oxide is a Group IVB metal oxide; and / or The binder is selected from at least one of liquid paraffin, hydroxymethyl cellulose, polyvinyl alcohol, starch and dextrin, and at least one of nitric acid, sulfuric acid, oxalic acid and citric acid.

13. The use of the catalyst according to any one of claims 1-12 in catalytic wet oxidation.

14. A method for treating organic wastewater, characterized in that, The method includes: reacting a salt-forming aid, organic wastewater, and an oxidant in the presence of a catalyst; The catalyst is the catalyst described in any one of claims 1-12.

15. The method according to claim 14, wherein, The conditions for the contact reaction include: The pH value of the material after the contact reaction is 2-6.5; and / or The acetic acid concentration of the material after the contact reaction is 3-20 wt%; and / or The COD value of the organic wastewater is 40,000-250,000 mg / L; and / or The salt-forming substance is at least one of ammonia, sodium hydroxide, and potassium hydroxide; and / or The oxidant is an oxygen-containing gas; and / or The volume ratio of oxygen to organic wastewater in the contact reaction system is 10-400; and / or The reaction temperature is 250-300℃; and / or The reaction pressure is 7-12.0 MPa; and / or The reaction time is 10-150 minutes; and / or The post-processing methods include distillation crystallization and / or cooling crystallization.

16. The method according to claim 15, wherein, The conditions for the contact reaction include: The pH value of the material after the contact reaction is 4-6.5; and / or The acetic acid concentration of the material after the contact reaction is 3-12 wt%; and / or The COD value of the organic wastewater is 40,000-150,000 mg / L; and / or The salt-forming substance is ammonia; and / or The reaction time is 10-120 minutes.

17. The method according to claim 16, wherein, The salt-forming substance is ammonia, and the molar ratio of ammonia to organic wastewater is 1.6-2.5, calculated as N / C.

18. The method according to claim 16, wherein, The salt-forming substance is ammonia, and the molar ratio of ammonia to organic wastewater is 1.8-2.2 (N / C ratio).

19. The method of claim 14, wherein, After the contact reaction, part of the material is recycled back to the organic wastewater, and the remainder is post-treated.

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