A superoxide catalytic oxidation catalyst and its preparation method

Abstract

The present invention relates to the field of catalytic materials, and particularly to a superoxide catalytic oxidation catalyst and a preparation method thereof. The method includes: using a titanium salt as a raw material, adding a fluorination reagent and a dispersion solvent to mix into a base mixed solution, adjusting the pH to weakly alkaline, and then carrying out a reaction under heat preservation and pressure to synthesize the superoxide catalytic oxidation catalyst in one step. The present invention can rapidly and effectively decompose the difficult-to-degrade organic substances in sewage, and has a broad-spectrum and high-efficiency disinfection and sterilization ability; relying on the excellent oxidation performance of its active oxygen, it can widely and efficiently kill bacteria and viruses. In addition, the cost-benefit is remarkable; compared with traditional wastewater treatment methods, the catalyst used in the present invention has a lower usage cost, and due to its high-efficiency characteristics, it can shorten the treatment time, thereby reducing the overall operating cost.

Description

Technical Field

[0001] The present invention relates to the field of catalytic materials, and particularly to a superoxide catalytic oxidation catalyst and a preparation method thereof. Background Art

[0002] In the current field of sewage treatment technology, many existing technical means are limited to achieving a single function, such as only being able to degrade organic matter in wastewater, or only being able to perform disinfection treatment to remove microorganisms such as bacteria and viruses in wastewater. However, these single-function technologies often face insurmountable problems, such as possible secondary pollution, or relatively low treatment efficiency, making it difficult to meet actual needs. Especially when dealing with wastewater containing multiple pollution factors, the situation is more complex. For example, wastewater may contain various pollutants such as organic matter, bacteria, and heavy metals, and a series of complex treatment processes are required for comprehensive treatment to ensure that the wastewater meets the discharge standards.

[0003] When dealing with difficult-to-degrade biopharmaceutical wastewater such as antibiotics, there is currently a lack of a treatment technology that is both efficient and low-cost. Such biopharmaceutical wastewater usually contains high concentrations of organic matter and difficult-to-decompose chemical substances, making the treatment process more difficult. Therefore, in order to achieve efficient and harmless degradation and disinfection treatment of wastewater, improve water resource utilization rate, and ensure environmental safety, the sewage treatment field urgently needs a safe and efficient degradation and disinfection treatment solution that can handle special wastewater (such as pharmaceutical wastewater).

[0004] This solution needs to have multiple functions, be able to simultaneously handle multiple pollution factors, including organic matter, bacteria, heavy metals, etc., and be able to effectively degrade difficult-to-decompose chemical substances (such as antibiotics). In addition, this solution also needs to have a high treatment efficiency, be able to complete wastewater treatment in a short time, reduce treatment costs, and at the same time ensure that the treated wastewater meets environmental protection discharge standards and does not cause secondary pollution to the environment. Summary of the Invention

[0005] The technical solution of the present invention aims at the technical problems such as complex process and secondary pollution existing in the current wastewater treatment process, and provides a superoxide catalytic oxidation catalyst and a preparation method thereof.

[0006] The main purposes of the present invention are as follows:

[0007] I. Efficiently degrade the difficult-to-degrade organic matter in the sewage water system;

[0008] II. Have extremely high oxidation activity and be able to kill microorganisms such as bacteria and viruses in the water system;

[0009] III. Be environmentally friendly and will not cause secondary pollution to the environment.

[0010] To achieve the above purposes, the present invention adopts the following technical solutions.

[0011] A preparation method of a superoxide catalytic oxidation catalyst

[0012] The method includes:

[0013] Using a titanium salt as a raw material, adding a fluorinating reagent and a dispersion solvent to mix into a base mixed solution, adjusting the pH to weakly alkaline, and then performing a heat preservation and pressure preservation reaction to synthesize the superoxide catalytic oxidation catalyst in one step.

[0014] Preferably,

[0015] The titanium salt is titanium sulfate;

[0016] The fluorinating reagent is hydrofluoric acid;

[0017] The dispersion solvent is deionized water.

[0018] Preferably,

[0019] The titanium salt, the fluorinating reagent and the dispersion solvent are mixed in a mass ratio of 1:(4.4 - 4.5):(17 - 23).

[0020] Preferably,

[0021] In the process of adjusting the pH to weakly alkaline, ammonia water is used to adjust the pH value to 8 - 9.

[0022] Preferably,

[0023] The ammonia water is saturated ammonia water;

[0024] Calculated based on the volume of the base mixed solution, 7 - 13 %VOL of ammonia water is added dropwise to the base mixed solution per minute.

[0025] Preferably,

[0026] In the heat preservation and pressure preservation reaction process, it is continuously reacted for 2 - 4 h under the conditions of an ambient pressure of 3 - 5 MPa and an ambient temperature of 40 - 50 °C.

[0027] Preferably,

[0028] After the heat preservation and pressure preservation reaction is completed, the obtained superoxide catalytic oxidation catalyst is dried and then post - heat - treated.

[0029] Preferably,

[0030] The post - heat - treatment process is as follows:

[0031] The superoxide catalytic oxidation catalyst is placed in a protective atmosphere, heated to 550 - 550 °C at a rate of 2 - 3 °C / min, and then kept warm for 1.5 - 2.5 h for crystal phase transformation.

[0032] A superoxide catalytic oxidation catalyst.

[0033] In the technical solution of the present invention, the core lies in using the liquid-phase one-step synthesis method to prepare the catalyst material, and based on the synergistic effect of other structures of the catalyst, highly active hydroxyl radicals and superoxide ions with strong oxidizing properties are efficiently generated, which combine with organic substances to carry out rapid reactions to achieve rapid and deep degradation of refractory organic pollutants in sewage. At the same time, the cell wall is damaged, ultimately causing the inactivation of bacteria and virus particles in the wastewater to achieve disinfection and sterilization.

[0034] In the technical solution of the present invention, by precisely controlling the core parameters in the synthesis process, including pH value, reaction temperature and pressure, and subsequent heat treatment conditions, it is ensured that the catalyst exhibits excellent high activity and stability. The material titanium oxide has a relatively wide bandgap property, which means that when it is irradiated with ultraviolet light, electrons in the valence band can absorb the energy provided by photons. These electrons will then transition to the conduction band, thus generating photo-generated electrons in the conduction band and photo-generated holes in the valence band. However, although this phenomenon has certain photocatalytic potential in theory, there are some limitations in the practical application of titanium oxide. Specifically, titanium oxide can only exhibit strong photocatalytic activity when irradiated with ultraviolet light with a wavelength less than 387 nm. Therefore, under the irradiation of daily visible light, the photocatalytic activity of titanium oxide is relatively poor, and the utilization rate of visible light is very limited. In addition, since photo-generated electrons and holes are prone to recombination in titanium oxide, this recombination process further limits its application scope and efficiency as a catalyst. Therefore, although the photocatalytic performance of titanium oxide under ultraviolet light is promising, these limitations still need to be overcome in practical applications to fully exert its potential catalytic ability. To overcome the problem of insufficient catalytic activity of titanium oxide in the visible light region, the present invention first adjusts the energy band structure of titanium oxide by fluorination, and secondly, by optimizing the morphology and structure of the catalyst, it is prepared into a nanostructure to increase the specific surface area of the catalyst, thereby providing more active sites and reducing the recombination probability of photo-generated electrons and holes, further improving the catalytic efficiency of the catalyst. Moreover, the fluorinated titanium oxide presents anatase phase and shows a high degree of crystallinity. With subsequent heat treatment, it is also observed that there is close contact between the irregular clusters on the catalyst surface, and this contact promotes the effective migration of the hole-electron pairs generated by photoexcitation, which is beneficial to improving the efficiency and effectiveness of the photocatalytic reaction. Through further comparative studies, when different titanium sources are used in the preparation process of the titanium oxide catalyst, the properties of the finally prepared catalytic materials are also different, because there are various interfacial electron transfer modes in the photocatalysis on titanium oxide, which will affect the formation of oxygen vacancies and the corresponding catalytic active centers during the subsequent heat treatment process. During the wastewater degradation process, the active sites rich on the surface layer of the catalyst can efficiently adsorb the organic pollutants contained in the sewage, and then catalyze the generation of hydroxyl radicals and superoxide ions. These highly active species react with the organic matter through oxidation reactions, effectively disintegrating its chemical structure, and realizing the rapid and deep treatment of difficult-to-degrade organic matter. In addition, the catalyst also has the ability to destroy the cell walls of bacteria and viruses, thus achieving the effect of disinfection and sterilization.

[0035] The photo-thermal catalytic synergy technology exhibits excellent oxidation performance and broad-spectrum and high-efficiency bactericidal and virucidal characteristics. This technology not only has the advantages of broad-spectrum high-efficiency, green pollution-free and high safety, but also can rapidly decompose organic substances, realize the purification treatment of wastewater, and achieve the technical goal of rapid degradation of organic substances and high-efficiency sterilization. Finally, the oxidation products are carbon dioxide and water, and the remaining reactive oxygen is converted into oxygen and released into the air. In the solution proposed in the present invention, based on titanium oxide with a nanoarray structure, the process of photocatalysis and oxygen synergistic catalytic oxidation is realized. Specifically, on the surface of the catalyst material, it can catalytically decompose adsorbed oxygen molecules to generate active groups such as oxygen free radicals. Such oxygen free radicals exhibit extremely high activity, with a half-life in the microsecond level, possessing excellent oxidation ability and high-efficiency sterilization efficacy, thus achieving the technical standard of high-efficiency degradation and killing of germs. This process does not produce secondary pollution and there are no residual substances, ensuring the safety of the surrounding environment.

[0036] In the embodiments of the present invention, by optimizing the preparation process of the catalyst, the performance of the photo-thermal catalytic synergy technology can be further improved. For example, by controlling the particle size and morphology of titanium oxide with a nanoarray structure, the specific surface area of the catalyst can be effectively increased, thereby improving its adsorption capacity for organic substances and bacteria. In addition, by introducing specific doping elements, the electronic structure of the catalyst can be adjusted, enhancing its light absorption ability, and thus improving the photocatalytic efficiency. In practical applications, the catalyst can be made into powder, granular or film form to adapt to different wastewater treatment equipment and technological processes. Through these optimization measures, the catalyst of the present invention shows excellent treatment effects when treating different types of wastewater such as industrial wastewater, domestic sewage and hospital wastewater, providing an efficient and environmentally friendly solution for the field of wastewater treatment.

[0037] The advantages of the present invention are as follows:

[0038] (1) High-efficiency degradation performance: This product can rapidly and effectively decompose the difficult-to-degrade organic substances in sewage;

[0039] (2) Broad-spectrum and high-efficiency disinfection and sterilization ability: Relying on the excellent oxidation performance of its reactive oxygen, it can widely and efficiently kill bacteria and viruses;

[0040] (3) Environmentally friendly characteristics: Its disinfection and sterilization factor - reactive oxygen, is derived from oxygen and dissolved oxygen in water, and will be converted into oxygen after completing the disinfection and sterilization task, without causing secondary pollution;

[0041] (4) Wide applicability: This product can be applied to the treatment of various types of wastewater, realizing effective degradation and disinfection and sterilization of various sewage;

[0042] (5) Significant cost-effectiveness: Compared with traditional wastewater treatment methods, the catalyst used in the present invention has lower usage costs and, due to its high efficiency, can shorten the treatment time, thereby reducing overall operating costs. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0044] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0045] Unless otherwise specified, the hydrofluoric acid used in the embodiments of the present invention is a commercially available 47% hydrogen fluoride solution.

[0046] Embodiment 1:

[0047] A method for preparing a superoxide catalytic oxidation catalyst,

[0048] The method comprises:

[0049] Titanium sulfate, hydrofluoric acid and deionized water are uniformly mixed in a mass ratio of 1:4.4:17 to prepare a base mixed solution. Then, in the one-step synthesis process, ammonia water needs to be added dropwise at a rate of 7%VOL / min of the base mixed solution until the pH of the base mixed solution is adjusted to 8. After the addition is completed, the reaction is stirred for 4 h in an environment with a pressure of 3 MPa and a temperature of 40 °C for one-step synthesis. After the reaction is completed, it is washed with distilled water and dried in an environment with a temperature of 80 °C. Then, it is kept warm in a muffle furnace with a heating rate of 2 °C / min and a heat treatment temperature of 500 °C for 2.5 h, and then naturally cooled to ambient temperature to prepare a superoxide catalytic oxidation catalyst.

[0050] The superoxide catalytic oxidation catalyst prepared in the example was subjected to performance testing, and the specific operation steps and characterization results are as follows.

[0051] COD detection of water samples: Collect the pharmaceutical wastewater from a pharmaceutical factory. The original COD value of the sampled wastewater is approximately 3613.1 - 3629.6 mg / L. Add the superoxide catalytic oxidation catalyst prepared in the example to the industrial wastewater at a dosage of 120 g / L for wastewater degradation. After exposure to the sun at 55 °C for 120 min, use a COD meter and a digestion instrument to detect the COD of the water sample under the temperature condition of 160 °C.

[0052] Escherichia coli detection: Collect the pharmaceutical wastewater. The original concentration of Escherichia coli in the sampled wastewater is approximately 1×10 5 ~1×10 6 CFU / L, and the original concentration of fecal coliforms is approximately 1×10 7 ~1×10 8 CFU / L. Add the superoxide catalytic oxidation catalyst prepared in the example to the industrial wastewater at a dosage of 120 g / L for wastewater degradation. After exposure to the sun at 55 °C for 120 min, detect the number of coliforms.

[0053] Table 1 Detection results of Example 1

[0054]

[0055] It can be clearly seen from the characterization results in Table 1 that after being treated by the present invention, the organic pollution degree of the discharged sewage can be effectively reduced. The treated wastewater can approach the Class B discharge standard (≤500 mg / L) when the sewage passes through secondary treatment. And due to the superoxide catalytic characteristics of the catalyst of the present invention, the removal effect on Escherichia coli is even more remarkable. The catalyst of the present invention has a good photo-thermal synergistic catalytic effect, which can stimulate the generation of a large number of hydroxyl radicals and superoxide ions, and can effectively degrade organic pollutants and kill Escherichia coli. To further prove the bactericidal ability of the catalyst of the present invention, collect the pharmaceutical wastewater of the same batch. The original concentration of Escherichia coli in the sampled wastewater is approximately 1×10 5 ~1×10 6 CFU / L, and the original concentration of fecal coliforms is approximately 1×10 7 ~1×10 8 CFU / L. After exposure to the sun at 55 °C for 120 min, detect the number of coliforms. The detection results show that the concentration of Escherichia coli still reaches ≥1×10 4 CFU / L, and the concentration of fecal coliforms still reaches ≥1×10 7 CFU / L, indicating that although the heating and sun exposure processes can achieve a certain degree of disinfection, and Escherichia coli and fecal coliforms are not heat-resistant bacteria, the disinfection efficiency of simple high-temperature sun exposure is low. In contrast, it is obvious that the catalyst of the present invention can carry out the effects of photo-thermal synergistic catalytic degradation of pollutants and killing harmful bacteria under the condition of medium-temperature heating combined with sun exposure.

[0056] Example 2:

[0057] A preparation method of a superoxide catalytic oxidation catalyst,

[0058] The method includes:

[0059] Mix titanium sulfate, hydrofluoric acid, and deionized water evenly according to a mass ratio of 1:4.45:20 to prepare a substrate mixed solution. Subsequently, during the one-step synthesis process, ammonia water needs to be added dropwise at a rate of 10 %VOL / min of the volume of the substrate mixed solution until the pH of the substrate mixed solution is adjusted to 8.5. After the addition is completed, stir and react for 3 h in an environment with a pressure of 4 MPa and a temperature of 45 °C for one-step synthesis. After the reaction is completed, wash with distilled water and dry in an environment with a temperature of 80 °C. Subsequently, keep warm for 2 h in a muffle furnace with a heating rate of 2 °C / min and a heat treatment temperature of 525 °C, and then naturally cool to the ambient temperature to prepare a superoxide catalytic oxidation catalyst.

[0060] Perform the same performance tests on the superoxide catalytic oxidation catalyst prepared in the example as in Example 1, and the characterization results are as follows.

[0061] Table 2 Detection results of Example 2

[0062]

[0063] From the characterization results in Table 2, it can also be clearly seen that the catalyst prepared in this example also has good effects on degrading organic pollutants and killing harmful bacteria. And compared with the sample in Example 1, the sample prepared in this example has a slightly improved effect on killing Escherichia coli, while the degradation of organic pollutants is basically the same.

[0064] Example 3:

[0065] A preparation method of a superoxide catalytic oxidation catalyst,

[0066] The method includes:

[0067] Mix titanium sulfate, hydrofluoric acid, and deionized water evenly according to a mass ratio of 1:4.5:23 to prepare a substrate mixed solution. Subsequently, during the one-step synthesis process, ammonia water needs to be added dropwise at a rate of 13 %VOL / min of the volume of the substrate mixed solution until the pH of the substrate mixed solution is adjusted to 9. After the addition is completed, stir and react for 2 h in an environment with a pressure of 5 MPa and a temperature of 50 °C for one-step synthesis. After the reaction is completed, wash with distilled water and dry in an environment with a temperature of 80 °C. Subsequently, keep warm for 1.5 h in a muffle furnace with a heating rate of 2 °C / min and a heat treatment temperature of 550 °C, and then naturally cool to the ambient temperature to prepare a superoxide catalytic oxidation catalyst.

[0068] The superoxide catalytic oxidation catalyst prepared in the examples was subjected to the same performance tests as in Example 1, and the characterization results are as follows.

[0069] Table 3 Test Results of Example 3

[0070]

[0071] From the characterization results in Table 3, it can also be clearly seen that the catalyst prepared in this example also has good effects on degrading organic pollutants and killing harmful bacteria. And compared with the sample in Example 1, the effect of the sample prepared in this example on killing Escherichia coli is basically the same, while there is a slight improvement in the degradation of organic pollutants.

[0072] Comparative Example 1:

[0073] A preparation method of a superoxide catalytic oxidation catalyst, the specific preparation method is the same as that in Example 2. In the comparative example, only the defined range of pH in the present invention is changed. Specifically, the pH of the substrate mixed solution is adjusted to 11, and the superoxide catalytic oxidation catalyst is prepared. The catalyst prepared in the comparative example was subjected to the same performance tests as in Example 1, and the characterization results are as follows.

[0074] Table 4 Test Results of Comparative Example 1

[0075]

[0076] From the results in Table 4, in this example, only more ammonia water was added during the one-step synthesis process, and the reaction was carried out in a more alkaline environment. And this will actually have a significant impact on the structure of the product. The impact is mainly reflected in the crystal structure. Because in a more alkaline condition, during the heat and pressure preservation reaction process, crystals will precipitate and aggregate faster, resulting in a decrease in the specific surface area of the product and the blockage of the pore structure. Intuitively, the particle size of the obtained product increases significantly, which leads to a decrease in the contact area and contact rate between the catalyst and pollutants (organic pollutants and harmful bacteria), resulting in a decrease in the treatment efficiency and treatment effect of the water body. In addition, since the catalyst in the system of the present invention is a one-step reaction centered on the hydrolysis process of titanium salt, the pH value will have a significant impact on the hydrolysis process and the doping process of fluoride ions. Because in the hydrolysis process and doping process, it is necessary to first construct TiO 2 / Ti(OH) 2 ·nH 2 O, and the present invention also additionally adds hydrogen fluoride as a fluorinating agent. If titanium fluoride is directly formed, it itself does not have the ability to stimulate hydroxyl radicals and superoxide ions for catalytic oxidation. However, through the regulation of the environmental pH value and the cooperation of the fluorinating agent in the present invention, ionic fluorine modification can be effectively realized, greatly enhancing the photothermal catalytic performance of the catalyst. Especially in terms of photocatalytic performance, appropriate pH value and the use of fluorinating agent can achieve in TiO2 / Ti(OH) 2 ·nH 2 O generates a large number of ≡Ti-F bonds and oxygen defects on the surface, thereby promoting the transfer of photo-generated electron-hole pairs, improving the absorption ability of the catalyst in the visible light region, and enhancing the photocatalytic degradation efficiency. However, in this example, due to the too high pH value of the reaction environment, it will cause TiO 2 / Ti(OH) 2 ·nH 2 O to further polymerize and inhibit the continuous forward hydrolysis reaction, resulting in an increase in the difficulty of doping with fluoride ions and ultimately a significant decrease in the performance of the catalyst.

[0077] Comparative Example 2:

[0078] A preparation method of a superoxide catalytic oxidation catalyst, and its specific preparation method is the same as that of Example 2. The comparative example only changes the limited range of temperature in the present invention. Specifically, after the dropping is completed, the reaction is stirred for 3 h in an environment with a pressure of 5 MPa and a temperature of 70 °C to prepare a superoxide catalytic oxidation catalyst. The catalyst prepared in the comparative example is subjected to the same performance test as that of Example 1, and the characterization results are as follows.

[0079] Table 5 Detection Results of Comparative Example 2

[0080]

[0081] In this example, a higher reaction temperature is adopted. Under different temperature conditions, the hydrolysis reaction process will be different. Under relatively low temperature conditions, such as 45 °C in Example 2, the hydrolysis reaction rate is relatively slow under relatively low temperature conditions, and the crystallinity of the product formed at this time is usually higher. Generally speaking, the higher the crystallinity, the greater the difficulty of doping with fluoride ions, which will lead to a worse doping effect of fluoride ions, because the orderliness of the crystal structure may hinder the insertion of fluoride ions. High temperature is beneficial to increasing the proportion of amorphous or low-crystallinity components of the product TiO 2 / Ti(OH) 2 ·nH 2 O, but for the technical solution of the present invention, since titanium sulfate and hydrogen fluoride are first mixed and preferentially mixed before adding ammonia water to adjust the pH value, it is beneficial to first form a Ti-F complex, thereby realizing deep doping of fluoride ions. Compared with first hydrolyzing to form TiO 2 / Ti(OH) 2 ·nH 2For the two-step method of doping and diffusing fluoride ions with hydrogen fluoride, the present invention improves the preparation efficiency and realizes more effective deep doping of fluoride ions. At the same time, the constructed complex is also beneficial to constructing the pore structure of the product, and to a certain extent, the "pitting corrosion" of hydrogen fluoride is used to construct a "pore template". On this basis, using a higher reaction temperature will actually lead to a decrease in the crystallinity of the product, and as a result, as shown in Table 5, the structural stability of the product will decrease, and it is easy to collapse. Especially during the post-heat treatment process, the pulverization of the product will be aggravated, resulting in a significant decrease in the catalytic degradation ability, which is instead not conducive to the preparation of high-quality catalysts.

[0082] Comparative Example 3:

[0083] A preparation method of a superoxide catalytic oxidation catalyst, the specific preparation method is the same as that of Example 2. The comparative example only changes the limited range of the pressure in the present invention. Specifically, after the dropping is completed, the reaction is stirred for 3 h in an environment with a pressure of 8 MPa and a temperature of 45 °C to prepare a superoxide catalytic oxidation catalyst. The catalyst prepared in the comparative example is subjected to the same performance test as that in Example 1, and the characterization results are as follows.

[0084] Table 6 Detection Results of Comparative Example 3

[0085]

[0086] Compared with Example 2 in this example, Comparative Example 3 uses a higher environmental pressure for the reaction. Generally speaking, pressure usually does not affect the reaction, but for the present invention, the used fluorinating agent and alkaline pH regulator are actually weak acids and weak bases, and there is an equilibrium position during the reaction. The change in pressure will cause the reaction equilibrium to change. The increase in pressure may increase the collision frequency between reactant molecules, thereby accelerating the reaction rate, and at the same time affect the solubility of titanium sulfate and hydrogen fluoride, and then affect the progress of the reaction. And due to the above-mentioned reaction intensification and reaction equilibrium change, more by-products such as TiF 4 will be produced, changing the existence form of fluoride ions, and will also affect the pore structure and change the crystal structure, resulting in a decrease in the comprehensive performance of the product as shown in Table 6.

[0087] By comprehensively analyzing the characterization results of Comparative Example 1, Comparative Example 2, and Comparative Example 3, the catalysts prepared in the comparative examples have poor degradation ability for organic pollutants in pharmaceutical wastewater and weak killing ability for microorganisms. Through further research and analysis, in the present invention, due to the ability of the catalyst to generate strongly oxidizing reactive oxygen species, it can achieve the purpose of rapidly degrading organic matter and efficiently sterilizing, but there are restrictions on the environment during the synthesis process. When the alkalinity is too high during the reaction process, the crystal form formed by titanium oxide on the surface of the catalyst is abnormal, thereby reducing the catalytic activity of the catalyst; when the temperature and pressure are too high during the reaction process, the two-dimensional structure of the nanocatalyst cannot be constructed due to the too high catalytic activity of the catalyst itself, thereby reducing the number of catalytic centers and resulting in a decrease in the catalyst activity.

[0088] Comparative Example 4:

[0089] A preparation method of a superoxide catalytic oxidation catalyst, the specific preparation method is the same as that of Example 2. In the comparative example, only the heat treatment of the catalyst in the present invention is not carried out, and the superoxide catalytic oxidation catalyst is prepared. In addition, the catalyst prepared in Example 2 and the catalyst prepared in this example are subjected to a cyclic life test, and the specific operation steps and characterization results are as follows.

[0090] Collect the same batch of pharmaceutical wastewater, divide it into 12 equal parts, with an average initial COD value of 3621.2 mg / L. Add the catalyst to the industrial wastewater according to a dosage ratio of 120 g / L for wastewater degradation. After exposure to the sun at 55 °C for 120 min, use a COD analyzer and a digestion instrument to detect the COD of the water sample at a temperature of 160 °C. Then take out the catalyst for the degradation of the next portion of wastewater. The operation during the degradation process is the same. The catalyst prepared in Example 2 and the catalyst prepared in this example are simultaneously used for multiple wastewater degradations, and the COD of the water sample is detected. The characterization results are as follows.

[0091] Table 7 Comparison of Detection Results between Example 2 and Comparative Example 4

[0092]

[0093] Analyze the characterization results in Table 7 above. The catalyst prepared in the comparative example initially had a stronger wastewater degradation ability. However, after heat treatment, the example maintained a catalytic activity of 99.69% during multiple cycles, while the comparative example only maintained a catalytic activity of 94.05%. At the same time, there were also slight differences in the initial catalytic performance. This is mainly because the post-heat treatment process of the present invention can, to a certain extent, affect the catalytic activity of the catalyst. More importantly, during this process, it can effectively stabilize the crystal structure of the product and achieve the transformation of part of the amorphous phase to the crystal phase, thereby greatly improving the structural stability of the catalyst. In addition, for the characterization results of this group of comparative examples, the catalyst prepared in Example 2 was subjected to a 20-cycle life test with the catalyst prepared in this example. The final results showed that after heat treatment, Example 2 maintained a catalytic activity of 97.61% during multiple cycles, while Comparative Example 4 only maintained a catalytic activity of 87.26%, showing a relatively obvious stability difference.

[0094] Comparative Example 5:

[0095] A preparation method of a superoxide catalytic oxidation catalyst, the specific preparation method is the same as that in Example 2. In the comparative example, only ammonia water in the present invention is not used for the preparation of the superoxide catalytic oxidation catalyst.

[0096] The experimental results show that if the pH value is not adjusted during the reaction process, then precipitates cannot be effectively formed. In the technical solution of the present invention, ammonia water can not only play a role in adjusting the pH value of the reaction system, but more importantly, it can also act as a main precipitating agent to promote the formation of precipitates. Through further research, it was found that the preparation method using ammonia water as a precipitating agent can significantly improve the activity and stability of the catalyst. During the pH value adjustment process, the addition of ammonia water helps to form uniform and dense catalyst particles, thereby showing better catalytic performance in the subsequent wastewater treatment process. In addition, the use of ammonia water also reduces the introduction of other impurities, ensuring the high purity of the catalyst, which is crucial for the reuse and long-term stability of the catalyst. Therefore, the technical solution of the present invention has significant technical advantages in the preparation of highly efficient superoxide catalytic oxidation catalysts.

Claims

1. A method for preparing a superoxide catalytic oxidation catalyst, characterized in that: The method comprises: Titanium sulfate is used as a raw material, hydrofluoric acid and deionized water are added to form a base mixed solution, and in a one-step synthesis process, the pH is adjusted to a weak alkaline state and then the superoxide catalytic oxidation catalyst is prepared by heat preservation and pressure maintenance reaction; The titanium sulfate, hydrofluoric acid and deionized water are mixed in a mass ratio of 1: (4.4-4.5): (17-23); The process of adjusting the pH to a weak alkaline state is to adjust the pH value to 8-9 with ammonia water; The heat preservation and pressure preservation reaction process is to react continuously for 2 to 4 hours under the conditions of an ambient pressure of 3 to 5 MPa and an ambient temperature of 40 to 50 °C; After the heat preservation and pressure maintenance reaction is completed, the obtained superoxide catalytic oxidation catalyst is dried and then post-heat treated; The post-heat treatment process is: The superoxide catalytic oxidation catalyst is placed in a protective atmosphere, heated to 550°C at a rate of 2-3°C / min, and then kept at this temperature for 1.5-2.5 hours to effect a crystal phase transformation.

2. The method for preparing a superoxide catalytic oxidation catalyst according to claim 1, characterized in that: The ammonia water is saturated ammonia water; The ammonia water is calculated based on the volume of the base mixed solution, and 7-13% VOL of the base mixed solution is added dropwise every minute.

3. A superoxide catalytic oxidation catalyst prepared by the method of any one of claims 1 to 2.

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