Catalyst for degrading carbonic ester peroxide as well as preparation method and application of catalyst

Abstract

The invention belongs to the technical field of peroxides, and discloses a catalyst for degrading carbonic ester peroxides as well as a preparation method and application of the catalyst. The catalyst takes Fe3O4 as a magnetic core, the magnetic core is coated with a SiO2 mesoporous layer, and the mesoporous layer is loaded with a metal oxide; the metal oxides are selected from two of Cu, Mn, Ni, Co, Ti, Mg and Mo. The method comprises the following steps: (1) mounting a 20-40kHz ultrasonic vibrator on the side wall of a reaction kettle, adding a catalyst into organic wastewater containing carbonic ester peroxide, and uniformly mixing; and (2) carrying out irradiation treatment by using 300-700W microwaves to realize the degradation of the carbonic ester peroxides. The catalytic degradation method disclosed by the invention is high in treatment efficiency, short in time, recyclable and low in treatment cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of peroxide, more particularly to a catalyst for degrading carbonate peroxide and a preparation method and application thereof. BACKGROUND

[0002] In the production and use of peroxide carbonates, especially peroxide dicarbonates (such as diisopropyl peroxide dicarbonate, dicyclohexyl peroxide dicarbonate), mixed wastewater such as strong acidic wastewater, strong alkaline wastewater, and product washing wastewater will be produced. Such wastewater usually contains organic peroxide (containing peroxide carbonate, peroxide ester, hydroperoxide, etc.), solvent and inorganic salt, and has the characteristics of strong irritating odor, difficult degradation, high toxicity, and poor biodegradability.

[0003] At present, the methods for degrading organic wastewater mainly include physical adsorption, biological decolorization, ultrasonic degradation, photocatalytic degradation, wet air oxidation, and microwave-assisted photocatalytic degradation. The biological method has a long treatment time and cannot completely degrade the pollutants in the wastewater. The adsorption method cannot degrade the pollutants, but only transfers their state. The photocatalytic method is only suitable for the treatment of low-concentration organic wastewater and has a long treatment time. The wet air oxidation method uses air as an oxidant under high temperature and high pressure, which requires high energy consumption and high equipment requirements. The ultrasonic degradation method has a long treatment time and low degradation efficiency. The microwave-assisted photocatalytic degradation method essentially uses microwave assistance to enhance the photocatalytic effect. The microwave catalyst materials used are mostly powders or granules, which are difficult to recover and cannot be reused. Some researchers add oxidizing agents such as hydrogen peroxide and chlorine dioxide when using microwave technology, which still does not deviate from traditional oxidation technology.

[0004] Chinese invention patent with publication number CN103663609A discloses a method for degrading COD in wastewater under microwave induction using an activated carbon loaded with manganese oxide catalyst. The catalyst can effectively remove organic matter in water. However, activated carbon has low strength and can cause secondary pollution. It cannot be reused multiple times, and the cost of the catalyst is high due to the high price of manganese.

[0005] Therefore, in order to overcome the defects of low treatment efficiency, long time, low utilization rate of oxidizing agent, and high treatment cost in the prior art, it is an urgent problem for those skilled in the art to propose a new microwave catalyst for degrading organic wastewater and a degradation method. SUMMARY

[0006] In view of this, the application provides a catalyst for degrading carbonate peroxide and a preparation method and application thereof. The catalyst with a "magnetic core-mesoporous shell-double active site" structure takes Fe3O4 nanoparticles as a magnetic core, coats a SiO2 mesoporous layer, forms a composite core-shell carrier, realizes rapid separation and recovery of the catalyst by using magnetism, improves substrate adsorption capacity by using the mesoporous structure, and improves catalytic activity by using the synergistic effect of double active sites through impregnation of double metal active components.

[0007] One of the purposes of the application is to provide a catalyst for degrading carbonate peroxide. The catalyst takes Fe3O4 as a magnetic core, coats a SiO2 mesoporous layer outside, and loads metal oxides on the mesoporous layer. The metal oxides are selected from two of Cu, Mn, Ni, Co, Ti, Mg, and Mo. The weight ratio of the magnetic core, the mesoporous layer, and the metal oxides is 6-7:2:1-2 by weight.

[0008] The metal oxides are located on the inner and outer surfaces of the pore channels of the mesoporous material.

[0009] Preferably, the metal oxides are compounded with one of Cu, Ti, and Mg and one of Mn, Ni, Co, and Mo.

[0010] Preferably, the specific area of the catalyst is 400-700 m 2 / g, and the pore size of the mesoporous layer is 10-25 nm, and the pore volume accounts for 20-50% of the total pore volume.

[0011] The second purpose of the application is to provide a preparation method of a catalyst for degrading carbonate peroxide, which comprises the following steps: (1) taking Fe3O4 as a magnetic core, coating a SiO2 layer by a sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles. The sol-gel method refers to a synthesis method of hydrolyzing silicate in an aqueous solution to generate silicon oxide. In a solution containing magnetic particles, a SiO2 layer is generated by hydrolyzing silicate.

[0012] (2) Excess metal salt solution with a total concentration of 3-5 mol / L is impregnated on the Fe3O4 / SiO2 core-shell nanoparticles, impregnated at room temperature for 2 h, dried, and calcined to obtain a catalyst for degrading carbonate peroxide.

[0013] Preferably, the metal salt solution is a mixed solution of two metal salts in an equimolar ratio.

[0014] Preferably, the calcination is calcination at 400-600°C for 2 h.

[0015] The third purpose of the application is to provide a method for degrading carbonate peroxide, which comprises the following steps: (1) Install a 20-40kHz ultrasonic transducer on the side wall of the reactor, add the catalyst to the organic wastewater containing carbonate peroxides, and mix evenly; use the ultrasonic cavitation effect to generate microbubbles, strengthen the contact between the catalyst and the substrate, and at the same time destroy the intermolecular forces of peroxides, and accelerate their diffusion to the catalyst surface.

[0016] (2) Use 300-700W microwave irradiation for more than 20 minutes to achieve the degradation of carbonate peroxides.

[0017] Preferably, the power of the ultrasonic transducer is 100-200W.

[0018] Preferably, the mass ratio of carbonate peroxides in the organic wastewater to the catalyst is 1:1-4.

[0019] More preferably, the carbonate peroxide is peroxide carbonate, and the peroxide carbonate content is 0.1-2 wt%.

[0020] Preferably, the catalyst is further recovered by magnetic separation after the degradation is completed.

[0021] As can be seen from the above technical solution, compared with the prior art, the technical effects achieved by the present invention are as follows: (1) The catalyst coating layer of the present invention is a mesoporous material, which can provide reaction space for macromolecular organic matter and allow small molecule pollutants to enter the inner catalyst matrix for reaction, thereby reducing the limitation of pollutant diffusion.

[0022] (2) This invention can quickly and effectively degrade organic pollutants in wastewater without the need to add expensive oxidants such as H2O2 and O3.

[0023] (3) The catalyst of this invention is supported on metal oxides and has good microwave absorption performance and catalytic activity. In the microwave-assisted degradation system of organic wastewater, it can catalyze the generation of active oxide species and rapidly and effectively degrade organic pollutants in the wastewater. The addition of Cu, Ti and Mg metal oxides changes the transfer capacity of lattice oxygen and electrons in the catalyst, increases the activity of the catalyst, improves the selectivity of the catalyst, and can also adjust the acidity and alkalinity of the catalyst, thereby improving the activity and selectivity of the catalyst and reducing the generation of side reactions.

[0024] (4) The raw materials used in this invention are widely available and the operation is simple. Moreover, the catalyst is easy to recover and can be reused, which can greatly promote the engineering application of microwave catalytic oxidation of organic wastewater. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1: A method for preparing a catalyst for degrading carbonate peroxides (1) Fe3O4 is used as a magnetic core, and SiO2 layer is coated by sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the specific steps and conditions are generally used in this field.

[0027] (2) Weigh 2 mol of manganese nitrate and copper nitrate and add them to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and soak them at room temperature for 2 h. Then dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0028] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0029] The specific area of ​​the obtained catalyst is approximately 640 m². 2 / g, the pore size of the mesoporous layer is 16nm, and the pore volume accounts for about 47% of the total pore volume.

[0030] Example 2: A method for preparing a catalyst for degrading carbonate peroxides (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0031] (2) Weigh 2 mol of cobalt nitrate and metatitanic acid and add them to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and immerse them at room temperature for 2 h. Then dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0032] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0033] The specific area of ​​the obtained catalyst is approximately 570 m². 2 / g, the pore size of the mesoporous layer is 17.2nm, and the pore volume accounts for about 40% of the total pore volume.

[0034] Example 3: A method for preparing a catalyst for degrading carbonate peroxides (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0035] (2) Weigh 2 mol of nickel nitrate and magnesium nitrate and add them to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution, let them stand at room temperature for 2 h, and dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h, and then cool it to room temperature to obtain the target catalyst.

[0036] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0037] The specific area of ​​the obtained catalyst is approximately 500 m². 2 / g, the pore size of the mesoporous layer is 21nm, and the pore volume accounts for about 28.4% of the total pore volume.

[0038] Example 4: A method for preparing a catalyst for degrading carbonate peroxides (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0039] (2) Weigh 2 mol of metatitanic acid and ammonium molybdate and add them to 1L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and soak them at room temperature for 2 h. Then dry them at 110℃ for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500℃ and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0040] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0041] The specific area of ​​the obtained catalyst is approximately 530 m². 2 / g, the pore size of the mesoporous layer is 19nm, and the pore volume accounts for about 30% of the total pore volume.

[0042] Comparative Example 1 (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0043] (2) Weigh 4 mol of manganese nitrate and add it to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and soak them at room temperature for 2 h. Then dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0044] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0045] The specific area of ​​the obtained catalyst is approximately 260 m². 2 / g, the pore size of the mesoporous layer is 46nm, and the pore volume accounts for about 11% of the total pore volume.

[0046] Comparative Example 2 (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0047] (2) Weigh 4 mol of copper nitrate and add it to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and soak them at room temperature for 2 h. Then dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0048] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0049] The specific area of ​​the obtained catalyst is approximately 230 m². 2 / g, the pore size of the mesoporous layer is 50nm, and the pore volume accounts for about 10% of the total pore volume.

[0050] Comparative Example 3 (1) Fe3O4 was used as the magnetic core, and SiO2 was coated by the sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; the same conditions as in Example 1 were used.

[0051] (2) Weigh 3 mol of manganese nitrate and 1 mol of copper nitrate and add them to 1 L of deionized water to obtain a solution. Immerse Fe3O4 / SiO2 core-shell nanoparticles in the solution and soak them at room temperature for 2 h. Then dry them at 110 °C for 2 h to obtain the catalyst precursor. Heat the obtained catalyst precursor to 500 °C and calcine it for 2 h. Then cool it to room temperature to obtain the target catalyst.

[0052] The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6:2:2.

[0053] The specific area of ​​the obtained catalyst is approximately 320 m². 2 / g, the pore size of the mesoporous layer is 33nm, and the pore volume accounts for about 14% of the total pore volume.

[0054] Example 5 provides a method for degrading carbonate peroxides. The catalysts prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to performance tests under the same conditions: (1) Install a 30kHz ultrasonic transducer (power 200W) on the side wall of the reactor, add the catalyst to the organic wastewater containing carbonate peroxides, and mix evenly; wherein, the mass ratio of peroxide carbonate in the organic wastewater to the catalyst is 1:3; the peroxide carbonate content in the wastewater is 0.5wt%.

[0055] Furthermore, percarbonates are the target pollutants in the wastewater, while other categories such as hydroperoxides, dialkyl peroxides, diacyl peroxides, and peroxyesters are coexisting peroxides that are either associated with or introduced by the process, with the content of coexisting peroxides ranging from 0.01 to 0.3 wt%.

[0056] (2) The patient was irradiated with 600W microwave for 30 minutes. The test results are shown in the table below: Table 1

[0057] Example 6 provides a method for degrading carbonate peroxides. The catalyst prepared in Example 1 was subjected to performance testing under the following conditions: (1) Install a 30kHz ultrasonic transducer (power 200W) on the side wall of the reactor, add the catalyst to the organic wastewater containing carbonate peroxides, and mix evenly; wherein, the mass ratio of peroxide carbonate in the organic wastewater to the catalyst is 1:3; the peroxide carbonate content in the wastewater is 0.5wt%; (2) The samples were irradiated with 600W microwave for 4, 8, 12, 16, 20, and 24 minutes. The test results are shown in the table below: Table 2

[0058] Comparative Example 4 provides a method for degrading carbonate peroxides. The catalyst prepared in Example 1 was subjected to performance testing under the following conditions: A 30kHz ultrasonic transducer (power 200W) was installed on the side wall of the reactor. A catalyst was added to the organic wastewater containing carbonate peroxides and mixed evenly. The mass ratio of carbonate peroxide in the organic wastewater to the catalyst was 1:3, and the carbonate peroxide content in the wastewater was 0.5wt%.

[0059] Without microwave irradiation for 30 minutes, the COD removal rate was measured to be 15.2%, and the carbonate peroxide removal rate was 32.11%.

[0060] Comparative Example 5 provides a method for degrading carbonate peroxides. The catalyst prepared in Example 1 was subjected to performance testing under the following conditions: (1) Add the catalyst to the organic wastewater containing carbonate peroxides in the reactor and mix evenly; wherein the mass ratio of carbonate peroxide in the organic wastewater to the catalyst is 1:3; the carbonate peroxide content in the wastewater is 0.5wt%. Do not install an ultrasonic transducer.

[0061] (2) After being irradiated with 600W microwave for 30 minutes, the COD removal rate was measured to be 55.3% and the carbonate peroxide removal rate was 51.20%.

[0062] Example 7: A method for degrading carbonate peroxides The catalyst prepared in Example 1 was subjected to performance testing under the following conditions: (1) Install a 30kHz ultrasonic transducer (power 200W) on the side wall of the reactor, add the catalyst to the organic wastewater containing carbonate peroxides, and mix evenly; wherein, the mass ratio of peroxide carbonate in the organic wastewater to the catalyst is 1:3; the peroxide carbonate content in the wastewater is 0.5wt%; (2) The catalyst was treated with 600W microwave irradiation for 30 minutes. After degradation, the catalyst was magnetically separated and recovered and dried. The above steps were repeated 5 times. The final COD removal rate was 67.1% and the carbonate peroxide removal rate was 92.67%.

[0063] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A catalyst for degrading carbonate peroxides, characterized in that, The catalyst has Fe3O4 as a magnetic core, covered with a SiO2 mesoporous layer, and the mesoporous layer supports a metal oxide; the metal oxide is selected from two of Cu, Mn, Ni, Co, Ti, Mg, and Mo. The weight ratio of the magnetic core, mesoporous layer, and metal oxide is 6-7:2:1-2.

2. The catalyst for degrading carbonate peroxides according to claim 1, characterized in that, The metal oxide is a compound of one of Cu, Ti, and Mg with one of Mn, Ni, Co, and Mo.

3. The catalyst for degrading carbonate peroxides according to claim 1, characterized in that, The catalyst has a specific surface area of ​​400-700 m². 2 / g, wherein the pore size of the mesoporous layer is 10-25nm, and the pore volume accounts for 20-50% of the total pore volume.

4. The method for preparing the catalyst for degrading carbonate peroxides according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Fe3O4 was used as a magnetic core and SiO2 was coated by sol-gel method to obtain Fe3O4 / SiO2 core-shell nanoparticles; (2) The Fe3O4 / SiO2 core-shell nanoparticles were impregnated with an excess of a metal salt solution with a total concentration of 3-5 mol / L, and then dried and calcined at room temperature for 2 h to obtain a catalyst for degrading carbonate peroxides.

5. The method for preparing the catalyst for degrading carbonate peroxides according to claim 4, characterized in that, The metal salt solution is a mixture of two metal salts in equimolar ratio.

6. The method for preparing the catalyst for degrading carbonate peroxides according to claim 4, characterized in that, The roasting process involves roasting at 400-600℃ for 2 hours.

7. A method for degrading carbonate peroxides, characterized in that, Includes the following steps: (1) Install a 20-40kHz ultrasonic transducer on the side wall of the reactor, add the catalyst prepared by any of the methods described in claims 4-6 to the organic wastewater containing carbonate peroxides, and mix them evenly; (2) Use 300-700W microwave irradiation to degrade carbonate peroxides.

8. The method for degrading carbonate peroxides according to claim 7, characterized in that, The power of the ultrasonic transducer is 100-200W.

9. The method for degrading carbonate peroxides according to claim 7, characterized in that, The mass ratio of carbonate peroxides to catalyst in the organic wastewater is 1:1-4.

10. The method for degrading carbonate peroxides according to claim 7, characterized in that, It also includes the magnetic separation and recovery of the catalyst after the degradation is completed.

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