A layered lattice iron bifunctional catalyst, its preparation method and application

Abstract

The present application provides a layered lattice iron bifunctional catalyst, a preparation method thereof, and an application thereof. The preparation method is to mix a layered structure material with deionized water to obtain a slurry, add the slurry to a nucleation reactor and stir vigorously, and stir cyclically for multiple times; then collect the slurry and centrifuge it to obtain a solid material, which is dried in vacuum to obtain a purified material; the obtained material is calcined at a high temperature for structural evolution to obtain the layered lattice iron bifunctional catalyst. The layered lattice iron bifunctional catalyst provided by the present application has a unique pore structure, a large specific surface area, and a wide pore size distribution, effectively adsorbing and enriching organic pollutants in water, providing a driving force for the Fenton oxidation degradation of low-concentration organic pollutants, and improving the Fenton oxidation degradation efficiency; the layered lattice Fe exists in the catalyst in the form of aluminum-oxygen-iron covalent bonds, the stability of Fe is improved, the dissolution amount of Fe during the oxidation degradation process is extremely low, and no iron sludge is generated, which is beneficial to the continuous progress of the removal reaction and the recycling of the catalyst.

Description

Technical Field

[0001] This application relates to the technical field of Fenton catalysts, and more specifically, to a layered lattice iron bifunctional catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of textile, papermaking, plastics, leather, electrolysis, resin, rubber, and other chemical industries, various industrial products have greatly enriched people's lives. However, the subsequent wastewater discharge directly affects the ecological environment and seriously threatens human health. Therefore, it is particularly urgent and important to develop an efficient and environmentally friendly treatment material and technology to promote the sustainable development of resources.

[0003] At present, a variety of treatment technologies for organic pollutants have been proposed at home and abroad, including adsorption method, membrane separation method, biodegradation method, advanced oxidation method, photocatalysis method, etc. Among them, the advanced oxidation method, especially the Fenton-like heterogeneous oxidation method, has attracted much attention because of its economic sustainability, environmental friendliness, and ability to completely degrade various organic pollutants in water. So far, iron-based catalysts have become one of the most commonly used Fenton catalysts due to their high catalytic performance and low cost. For example, in the literature A.M. Mesquita, I.R. G.M.M.D. Castro, M.A. T.C. Ramalho, M.C. Guerreiro, Appl. Catal. B Environ. 2016, 192, 286 - 295, goethite-derived iron oxide (Gt-B1×4) was used to remove methylene blue, an organic dye in water. The adsorption technology helps to enrich low-concentration pollutants on the catalyst surface, thereby accelerating the Fenton oxidation process. On the other hand, it also realizes the in-situ regeneration of the catalyst. Therefore, many researchers have prepared iron-based catalysts through composite structures to improve the Fenton oxidation degradation efficiency. For example, in the literature P. Zhou, Z. Dai, T. Lu, X. Ru, M.A. Ofori, W. Yang, J. Hou, H. Jin, Catalysts, 2022, 12, 669, an iron-loaded attapulgite Fenton catalyst was prepared for the removal of rhodamine B in water; in the literature C. Wang, R. Sun, R. Huang, J. Clean. Prod. 2021, 297, 126681, iron was doped into biochar to remove rhodamine B in water, but there is still a problem of decreased cycling performance due to the loss of active species.

[0004] In summary, there are two main challenges in the practical application of common Fenton catalysts: (1) low efficiency in treating low-concentration actual wastewater; (2) a large amount of dissolution of iron-based active species in the low pH range, forming iron sludge, resulting in a decline in the degradation performance and recycling performance of the Fenton catalyst. Therefore, how to solve the above challenges faced by the Fenton catalyst and design and develop a high-performance, high-stability and low-cost Fenton catalyst has become a research hotspot and focus. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present application provides a layered lattice iron bifunctional catalyst, a preparation method thereof and an application. The layered lattice iron bifunctional catalyst provided by the present application has a unique pore structure, a large specific surface area and a wide pore size distribution, which can effectively adsorb organic pollutants in water, enrich them on the material surface, provide a driving force for the Fenton oxidation degradation of low-concentration organic pollutants, and improve the Fenton oxidation degradation efficiency; the layered lattice Fe exists in the catalyst in the form of aluminum-oxygen-iron (Al-O-Fe) covalent bonds, the stability of Fe is improved, and the dissolution amount of Fe during the oxidation degradation process is extremely low, and no iron sludge is generated, which is beneficial to the continuous progress and recycling of the removal reaction.

[0006] In order to achieve the above object, in the first aspect, the present application provides a preparation method of a layered lattice iron bifunctional catalyst, comprising the following steps:

[0007] Step 1: Mix the layered structure material with deionized water evenly to obtain a slurry, add the slurry to a nucleation reactor and stir vigorously, add the stirred slurry to the nucleation reactor again and continue stirring, and repeat the cycle for multiple times; then collect the slurry for centrifugation, and vacuum dry the solid material obtained by centrifugation to obtain a purified and size-selected material;

[0008] Step 2: Calcinate the material obtained in Step 1 at a high temperature for structural evolution to obtain the layered lattice iron bifunctional catalyst.

[0009] Further, the layered structure material in Step 1 includes any one or a combination of two of attapulgite containing iron or iron-based hydrotalcite.

[0010] Preferably, the relative content of Fe in the layered structure material in Step 1 is 10.83 wt.% to 20.48 wt.%.

[0011] Further, the mass ratio of the layered structure material to deionized water is 1:1000 to 1:100.

[0012] Further, the mass of the layered structure material in Step 1 is 1 to 25000 g.

[0013] Further, the parameters of the nucleation reactor in step 1 are set as follows: the stator-rotor slit width is 0.05 - 0.5 mm, and the rotation speed is 100 - 3000 rpm.

[0014] Further, the number of cycles in step 1 is 2 - 10 times.

[0015] Further, the drying temperature in step 1 is 60 °C, and the time is 6 h.

[0016] Further, the high-temperature calcination temperature in step 2 is 150 - 700 °C, the heat preservation time is 1 - 5 h, and the heating rate is 4 - 10 °C / min.

[0017] In a second aspect, the present invention provides a layered lattice iron bifunctional catalyst prepared by the above preparation method.

[0018] Further, the Zeta potential of the layered lattice iron bifunctional catalyst is -32.26 - 45.16 mV, the specific surface area is 63.97 - 146.98 m 2 / g, and the pore diameter is 13.34 - 26.89 nm.

[0019] Further, the molar ratio of divalent iron to trivalent iron (Fe(II) / Fe(III)) in the layered lattice iron bifunctional catalyst is 0.54 - 1.94.

[0020] In a third aspect, the present invention provides the application of the above layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants.

[0021] Further, the method for degrading and removing organic pollutants includes the following steps:

[0022] Step S1: Select an organic pollutant, and adjust the concentration and pH of the pollutant solution.

[0023] Step S2: Adjust the temperature of the reaction system.

[0024] Step S3: Put the layered lattice iron bifunctional catalyst into the pollutant solution, perform the first oscillation, and then add H2O2 for the second oscillation to make the reaction complete, so as to achieve the removal of organic pollutants.

[0025] Preferably, the organic pollutant in step S1 is any one or a mixture of methylene blue, methyl orange, congo red, rhodamine B, tetracycline hydrochloride, doxycycline hydrochloride, ciprofloxacin, phenol, bisphenol A, or 2,4-dichlorophenol; the concentration of the pollutant solution is adjusted to 10 - 30000 mg / L, the volume is 0.05 - 2 L, and the pH of the pollutant solution is 2 - 14.

[0026] More preferably, 1M sulfuric acid or sodium hydroxide is used to adjust the pH of the pollutant solution.

[0027] Preferably, the temperature of the reaction system in step S2 is 20-80°C.

[0028] Preferably, in step S3, the first oscillation time is 0-120 min; the purity of H2O2 is 10 wt.% - 30 wt.%, and the mass fraction ratio of H2O2 to the layered lattice iron bifunctional catalyst is 1:100 - 1:10; the second oscillation time is 0-120 min.

[0029] More preferably, both the first oscillation and the second oscillation are carried out under dark conditions.

[0030] Preferably, the method for degrading and removing organic pollutants further includes the recovery of the layered lattice iron bifunctional catalyst. The specific method is to filter the mixed solution of the layered lattice iron bifunctional catalyst after the reaction through a 0.22 μm filter membrane, wash the residual organic matter on the surface with deionized water, and dry it at 60°C for 6 h under vacuum conditions.

[0031] The technical solution provided by this application has at least the following beneficial effects compared with the prior art:

[0032] 1) The present invention uses a nucleation reactor to disperse and control the size of layered structure materials (including iron-rich attapulgite clay minerals and iron-based hydrotalcite), and then activates the crystals of the materials through structural evolution, adjusts the controllable exposure of iron and the valence ratio of iron, and obtains a layered lattice iron bifunctional catalyst; the present invention innovatively and controllably synthesizes a bifunctional catalyst rich in layered lattice iron and applies it to the adsorption-Fenton coupling degradation and removal of organic pollutants in water, realizing the theoretical guidance of practical applications;

[0033] 2) The layered lattice Fe bifunctional catalyst prepared by the present invention has a unique pore structure, a large specific surface area, and a wide pore size distribution, and can effectively adsorb organic pollutants in water during use, enrich them on the material surface, provide a driving force for the Fenton oxidation degradation of low-concentration organic pollutants, and improve the Fenton oxidation degradation efficiency;

[0034] 3) The layered lattice Fe in the present invention exists stably in the catalyst through Al-O-Fe covalent bonds, the stability of Fe is improved, the dissolution amount of Fe during the oxidation degradation process is extremely low, and no iron sludge is generated, which is beneficial to the continuous progress and recycling of the removal reaction;

[0035] 4) When the catalyst of the present invention performs a removal reaction, H2O2 adsorbed on the catalyst surface can be activated in situ by it, thereby generating hydroxyl radicals, shortening the distance between the hydroxyl radicals and the pollutants; at the same time, the layered lattice Fe of the present invention accelerates the electron transfer between the organic pollutant-catalyst-H2O2, promotes the reduction of Fe(III) on the catalyst surface to Fe(II), accelerates the Fe(III) / Fe(II) cycle, increases the catalytic degradation rate of the Fenton reaction, and increases the degree of mineralization degradation of organic pollutants;

[0036] 5) The layered lattice iron bifunctional catalyst of the present invention achieves a certain degree of in-situ regeneration without the need for elution with organic solvents, acids, or bases. The process is simple to operate, flexible in form, and does not produce toxic or harmful by-products. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a data diagram of the iron phase composition characterization of the sample in Example 1 using a Topologic Systems 500A Mössbauer spectrometer;

[0038] Figure 2 The figure shows the crystal structure of the sample of Example 1 using an XRD-6000 X-ray powder diffractometer;

[0039] Figure 3 A structural model diagram of the sample in Example 1 constructed using the software Vesta;

[0040] Figure 4 This is a data diagram of group characterization of the sample in Example 1 using a TENSOR II Fourier transform infrared spectrometer;

[0041] Figure 5 This is a data diagram showing the Fe valence state characterization of the sample in Example 1 using a Thermo Fisher X-ray photoelectron spectrometer;

[0042] Figure 6 This is a data graph showing the pore structure characterization of the sample in Example 1 using a 3QDS-MP-30 specific surface area and pore size analyzer. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to understand the present application more clearly, the present application is further described in detail below in conjunction with examples and drawings. However, it should be understood that the following examples are only preferred implementation methods of the present application, and the scope of protection required by the present application shall be based on the scope defined in the claims.

[0044] In the description of the present invention, it should be noted that for those not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0045] <Example>

[0046] Example 1

[0047] A layered lattice iron bifunctional catalyst is prepared by the following method:

[0048] Step 1: Mix 5 g of attapulgite with an iron content of 14.64 wt.% with 5000 mL of deionized water to obtain a slurry. Set the stator-rotor slit width of the nucleation reactor to 0.3 mm and the rotation speed to 500 rpm. Add the slurry to the nucleation reactor and stir vigorously. The stirred slurry is added to the nucleation reactor again for continuous stirring, and the cycle is repeated 6 times; then collect the slurry for centrifugation. The solid material obtained by centrifugation is dried at 60 °C in vacuo to obtain a purified and size-selected material;

[0049] Step 2: Set the heating rate to 5 °C / min, and calcine the material obtained in Step 1 at 150 °C for 4 h for structural evolution, thus obtaining the product.

[0050] Testing:

[0051] 1. Use a 500A Mössbauer spectrometer from Topologic Systems of Japan to characterize the iron phase composition of the sample. The results are as Figure 1 shown. It can be Figure 1 seen that the iron composition includes Fe(II), Fe(III) and Fe2O3.

[0052] 2. Use an XRD-6000 X-ray powder diffractometer from Shimadzu Corporation of Japan to characterize the crystal structure of the sample and perform refinement. The results are as Figure 2 shown. Further, a structure model is constructed according to the software Vesta. The results are as Figure 3 shown. It can be Figure 2 and Figure 3 seen that the iron in the catalyst exists in the form of M-O-Fe bonds, and the metal M is Mg or Al.

[0053] 3. Use a TENSOR II Fourier transform infrared spectrometer from Bruker Corporation of Germany to characterize the groups of the sample. The results are as Figure 4 shown. It can be Figure 4 seen that the iron in the catalyst exists in the form of Al-O-Fe bonds.

[0054] 4. The X-ray photoelectron spectrometer of Thermo Company in the United States was used to characterize the Fe valence state of the sample, and the results are as Figure 5 shown. It can be seen from Figure 5 that the molar ratio of Fe(II) / Fe(III) is 0.79.

[0055] 5. The 3QDS-MP-30 specific surface area and pore size analyzer of Quantachrome Company in the United States was used to characterize the pore structure of the sample, and the results are as Figure 6 shown. It can be seen from Figure 6 that the specific surface area and average pore diameter of the catalyst are 146.98 m 2 / g and 13.34 nm respectively.

[0056] 6. The Zetasizer Nano ZS nano particle size and Zeta potential analyzer of Malvern Instruments in the UK was used to characterize the surface properties of the sample, and the measured Zeta potential is -6.88 mV.

[0057] It can be seen from the above tests that the layered lattice Fe bifunctional catalyst prepared in this example has the potential to be used as an adsorption and Fenton catalyst.

[0058] Example 2

[0059] A layered lattice iron bifunctional catalyst is prepared by the following method:

[0060] Step 1: 10 g of attapulgite with an iron content of 10.83 wt.% was mixed evenly with 1000 mL of deionized water to obtain a slurry. The stator-rotor slit width of the nucleation reactor was set to 0.15 mm and the rotation speed was 1500 rpm. The slurry was added to the nucleation reactor and stirred vigorously. The stirred slurry was added to the nucleation reactor again and stirred continuously for 8 cycles. Subsequently, the slurry was collected and centrifuged. The solid material obtained by centrifugation was dried at 60 °C in vacuum to obtain the purified and size-selected material;

[0061] Step 2: The heating rate was set to 6 °C / min, and the material obtained in Step 1 was calcined at 450 °C for 5 h for structural evolution, thus obtaining the product.

[0062] The relevant tests were carried out using the same method as in Example 1. The results showed that the iron in the obtained layered lattice iron bifunctional catalyst exists in the form of Al-O-Fe bonds. The iron composition includes Fe(II), Fe(III) and Fe2O3. The Fe(II) / Fe(III) is 1.22, the Zeta potential is -20.09 mV, and the specific surface area and average pore diameter are 63.97 m 2 / g and 25.98 nm respectively.

[0063] Example 3

[0064] A layered lattice iron bifunctional catalyst is prepared by the following method:

[0065] Step 1: Mix 1 g of aluminum-iron hydrotalcite with an iron content of 13.17 wt.% evenly with 500 mL of deionized water to obtain a slurry. Set the stator-rotor slit width of the nucleation reactor to 0.05 mm and the rotation speed to 100 rpm. Add the slurry to the nucleation reactor and stir vigorously. Then add the stirred slurry back into the nucleation reactor and continue stirring for 2 cycles. Subsequently, collect the slurry and perform centrifugation. The solid material obtained by centrifugation is dried in vacuo at 60 °C to obtain a purified and size-selected material;

[0066] Step 2: Set the heating rate to 4 °C / min and calcine the material obtained in Step 1 at 650 °C for 2 h for structural evolution, thus obtaining the catalyst.

[0067] Using the same method as in Example 1 for relevant tests, the results show that the iron in the obtained layered lattice Fe bifunctional catalyst exists in the form of Al-O-Fe bonds. The iron composition includes Fe(II), Fe(III), and Fe2O3, the Fe(II) / Fe(III) is 1.64, the Zeta potential is 45.16 mV, and the specific surface area and average pore diameter are 75.82 m 2 / g and 14.11 nm, respectively.

[0068] Example 4

[0069] A layered lattice iron bifunctional catalyst is prepared by the following method:

[0070] Step 1: Mix 25000 g of attapulgite with an iron content of 15.79 wt.% evenly with 2500 L of deionized water to obtain a slurry. Set the stator-rotor slit width of the nucleation reactor to 0.35 mm and the rotation speed to 2000 rpm. Add the slurry to the nucleation reactor and stir vigorously. Then add the stirred slurry back into the nucleation reactor and continue stirring for 10 cycles. Subsequently, collect the slurry and perform centrifugation. The solid material obtained by centrifugation is dried in vacuo at 60 °C to obtain a purified and size-selected material;

[0071] Step 2: Set the heating rate to 10 °C / min and calcine the material obtained in Step 1 at 700 °C for 1 h for structural evolution, thus obtaining the catalyst.

[0072] The relevant tests were carried out using the same method as in Example 1. The results showed that the iron in the obtained layered lattice Fe bifunctional catalyst existed in the form of Al-O-Fe bonds. The iron composition included Fe(II), Fe(III), and Fe2O3. The Fe(II) / Fe(III) was 1.94, the Zeta potential was -32.26 mV, and the specific surface area and average pore diameter were 75.89 m 2 / g and 26.89 nm respectively.

[0073] Example 5

[0074] A layered lattice iron bifunctional catalyst was prepared by the following method:

[0075] Step 1: 1000 g of aluminum-iron hydrotalcite with an iron content of 20.48 wt.% was mixed evenly with 200 L of deionized water to obtain a slurry. The stator-rotor slit width of the nucleation reactor was set to 0.5 mm, and the rotation speed was 3000 rpm. The slurry was added to the nucleation reactor and stirred vigorously. The stirred slurry was added to the nucleation reactor again and stirred continuously for 5 cycles. Subsequently, the slurry was collected and centrifuged. The solid material obtained by centrifugation was dried in a vacuum at 60 °C for 6 h to obtain a purified and size-selected material;

[0076] Step 2: The heating rate was set to 8 °C / min, and the material obtained in Step 1 was calcined at 250 °C for 3 h for structural evolution to obtain the product.

[0077] The relevant tests were carried out using the same method as in Example 1. The results showed that the iron in the obtained layered lattice Fe bifunctional catalyst existed in the form of Al-O-Fe bonds. The iron composition included Fe(II) and Fe(III). The Fe(II) / Fe(III) was 0.54, the Zeta potential was 35.11 mV, and the specific surface area and average pore diameter were 104.77 m 2 / g and 18.15 nm respectively.

[0078] Example 6

[0079] Application of the layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants:

[0080] Tetracycline hydrochloride (TCH) was selected as the target pollutant, and its solution concentration was adjusted to 50 mg / L, the solution volume was 0.1 L, the pH was adjusted to 4 with 1 M sulfuric acid, the reaction system temperature was set at 30 °C. 0.07 g of the layered lattice iron bifunctional catalysts obtained in Examples 1-5 were respectively added into the TCH solution, and the first oscillation was carried out for 60 min in a shaker at 150 rpm under dark conditions. Then 0.7 mg of 30 wt.% H2O2 was added, and the second oscillation was carried out for 120 min to achieve the removal of organic pollutants. The removal performance is shown in Table 1 (i.e., after a single experiment in Table 1).

[0081] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, and the surface residual organic matter was washed with deionized water, and then dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-added into the pollutant solution to degrade and remove organic pollutants in a cycle. The removal performance after 20 cycles is shown in Table 1 (i.e., after 20 cycles in Table 1).

[0082] As can be seen from Table 1, for a single experiment, the removal efficiencies of Examples 1-5 were 75.40%, 77.60%, 80.37%, 85.20% and 98.15% respectively; the COD removal rates were 46.29%, 49.40%, 58.11%, 65.26% and 76.84% respectively; the iron dissolution amounts were 0.0009, 0.0010, 0.0013, 0.0023 and 0.0011 mg / L respectively. For 20 cycles: the removal efficiencies of Examples 1-5 could still reach 70.39%, 73.74%, 78.53%, 82.19% and 90.35% respectively; the COD removal rates could still reach 41.56%, 40.41%, 52.41%, 60.16% and 70.18% respectively; the iron dissolution amounts could still be as low as 0.0018, 0.0020, 0.0023, 0.0037 and 0.0031 mg / L respectively. The total volume of the polluted object treated this time reached 2 L.

[0083] Example 7

[0084] Application of the layered lattice iron bifunctional catalyst in degrading and removing organic pollutants:

[0085] Doxycycline hydrochloride (DCH) was selected as the target pollutant, and its solution concentration was adjusted to 20 mg / L, the solution volume was 0.5 L, 1 M sulfuric acid was used to adjust the pH to 4, the reaction system temperature was set at 35 °C, 0.05 g of the layered lattice iron bifunctional catalyst obtained in Example 1 was put into the DCH solution, and it was first shaken in a shaker at 150 rpm for 120 min under dark conditions. Then 5.0 mg of 10 wt.% H2O2 was added, and it was shaken for a second time for 120 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate and iron dissolution amount were 92.74%, 70.47% and 0.0020 mg / L respectively.

[0086] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the surface residual organic matter was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-put into the pollutant solution to cyclically degrade and remove organic pollutants. After 50 cycles, the removal efficiency, COD removal rate and iron dissolution amount were 86.73%, 65.53% and 0.0137 mg / L, and the total volume of the treated pollutant reached 25 L this time.

[0087] Example 8

[0088] Application of the layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants:

[0089] Methylene blue (MB) was selected as the target pollutant, and its solution concentration was adjusted to 500 mg / L, the solution volume was 0.2 L, 1 M sulfuric acid was used to adjust the pH to 2, the reaction system temperature was set at 60 °C, 0.10 g of the layered lattice iron bifunctional catalyst obtained in Example 2 and 10 mg of 25 wt.% H2O2 were put into the MB solution, and it was shaken in a shaker at 150 rpm for 60 min under dark conditions to achieve the removal of organic pollutants. The removal efficiency, COD removal rate and iron dissolution amount were 100.00%, 82.47% and 0.0048 mg / L respectively;

[0090] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the surface residual organic matter was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-put into the pollutant solution to cyclically degrade and remove organic pollutants. After 100 cycles, the removal efficiency, COD removal rate and iron dissolution amount were 93.77%, 75.53% and 0.0217 mg / L, and the total volume of the treated pollutant reached 20 L this time.

[0091] Example 9

[0092] Application of Layered Lattice Iron Bifunctional Catalyst in Degrading and Removing Organic Pollutants:

[0093] Methyl orange (MO) was selected as the target pollutant. Its solution concentration was adjusted to 200 mg / L, the solution volume was 0.4 L, the pH was adjusted to 10 with 1 M sulfuric acid, the reaction system temperature was set at 50 °C, 0.10 g of the layered lattice iron bifunctional catalyst obtained in Example 3 and 2.5 mg of 15 wt.% H2O2 were added into the MO solution, and it was oscillated in a shaker at 150 rpm under dark conditions for 100 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate, and iron dissolution amount were 93.28%, 76.37%, and 0.0036 mg / L, respectively;

[0094] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the residual organic matter on the surface was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-added into the pollutant solution to cyclically degrade and remove organic pollutants. After 50 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 89.39%, 65.94%, and 0.0162 mg / L, and the total volume of the treated pollutant reached 20 L this time.

[0095] Example 10

[0096] Application of Layered Lattice Iron Bifunctional Catalyst in Degrading and Removing Organic Pollutants:

[0097] Ciprofloxacin (CIP) was selected as the target pollutant. Its solution concentration was adjusted to 10 mg / L, the solution volume was 0.05 L, the pH was adjusted to 7 with 1 M sulfuric acid, the reaction system temperature was set at 20 °C, 0.02 g of the layered lattice iron bifunctional catalyst obtained in Example 4 was added into the CIP solution, and it was oscillated for the first time in a shaker at 150 rpm under dark conditions for 60 min, then 1 mg of 30 wt.% H2O2 was added and it was oscillated for the second time for 30 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate, and iron dissolution amount were 82.11%, 50.23%, and 0.0010 mg / L, respectively;

[0098] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the residual organic matter on the surface was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-added into the pollutant solution to cyclically degrade and remove organic pollutants. After 60 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 77.24%, 45.82%, and 0.0018 mg / L, and the total volume of the treated pollutant reached 3 L this time.

[0099] Example 11

[0100] Application of layered lattice iron bifunctional catalyst in degradation and removal of organic pollutants:

[0101] Select Congo red (CR) as the target pollutant, adjust its solution concentration to 100 mg / L, the solution volume to 1 L, adjust the pH to 6 with 1 M sulfuric acid, set the reaction system temperature to 70 °C, put 0.15 g of the layered lattice iron bifunctional catalyst obtained in Example 5 into the CR solution, conduct the first oscillation for 30 min in a shaker at 150 rpm under dark conditions, add 1.5 mg of 20 wt.% H2O2, and conduct the second oscillation for 30 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate and iron dissolution amount are 96.63%, 73.48% and 0.0043 mg / L respectively;

[0102] Filter the mixed solution of the layered lattice iron bifunctional catalyst after the reaction through a 0.22 μm filter membrane, wash the residual organic matter on the surface with deionized water, dry it at 60 °C under vacuum conditions, and put the recovered layered lattice iron bifunctional catalyst back into the pollutant solution to recycle the degradation and removal of organic pollutants. After 50 cycles, the removal efficiency, COD removal rate and iron dissolution amount are 95.14%, 70.63% and 0.0093 mg / L respectively, and the total volume of the treated pollutant reaches 50 L this time.

[0103] Example 12

[0104] Application of layered lattice iron bifunctional catalyst in degradation and removal of organic pollutants:

[0105] Select Rhodamine B (Rh B) as the target pollutant, adjust its solution concentration to 400 mg / L, the solution volume to 0.15 L, adjust the pH to 10 with 1 M sulfuric acid, set the reaction system temperature to 25 °C, put 0.08 g of the layered lattice iron bifunctional catalyst obtained in Example 5 into the Rh B solution, conduct the first oscillation for 60 min in a shaker at 150 rpm under dark conditions, add 2.0 mg of 25 wt.% H2O2, and conduct the second oscillation for 60 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate and iron dissolution amount are 94.28%, 77.33% and 0.0013 mg / L respectively;

[0106] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the residual organic matter on the surface was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was redispersed into the pollutant solution to cyclically degrade and remove organic pollutants. After 20 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 90.31%, 72.22%, and 0.0081 mg / L, respectively. The total volume of the treated pollutants reached 3 L this time.

[0107] Example 13

[0108] Application of the layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants:

[0109] Phenol was selected as the target pollutant, and its solution concentration was adjusted to 15000 mg / L, and the solution volume was 2 L. The pH was adjusted to 14 with 1 M sulfuric acid. The reaction system temperature was set at 60 °C. 6 g of the layered lattice iron bifunctional catalyst obtained in Example 3 was added to the Phenol solution, and it was first shaken in a shaker at 150 rpm for 120 min under dark conditions. Then 60 mg of 23.6 wt.% H2O2 was added, and it was shaken for a second time for 90 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate, and iron dissolution amount were 98.16%, 72.47%, and 0.0069 mg / L, respectively;

[0110] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, the residual organic matter on the surface was washed with deionized water, and it was dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was redispersed into the pollutant solution to cyclically degrade and remove organic pollutants. After 50 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 89.24%, 65.53%, and 0.0101 mg / L, respectively. The total volume of the treated pollutants reached 100 L this time.

[0111] Example 14

[0112] Application of the layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants:

[0113] Bisphenol A (BPA) was selected as the target pollutant, and its solution concentration was adjusted to 30000 mg / L, with a solution volume of 1 L. 1 M sulfuric acid was used to adjust the pH to 3, and the reaction system temperature was set at 80 °C. 2.5 g of the layered lattice iron bifunctional catalyst obtained in Example 4 was put into the BPA solution, and the first oscillation was carried out in a shaker at 150 rpm under dark conditions for 90 min. Then 60 mg of 30 wt.% H2O2 was added, and the second oscillation was carried out for 120 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate, and iron dissolution amount were 96.74%, 72.30%, and 0.0048 mg / L, respectively.

[0114] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, and the surface residual organic matter was washed with deionized water and dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-put into the pollutant solution to cycle the degradation and removal of organic pollutants. After 100 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 82.79%, 50.35%, and 0.0042 mg / L, respectively, and the total volume of the polluted object treated this time reached 100 L.

[0115] Example 15

[0116] Application of the layered lattice iron bifunctional catalyst in the degradation and removal of organic pollutants:

[0117] 2,4-Dichlorophenol (2,4-DCP) was selected as the target pollutant, and its solution concentration was adjusted to 10 mg / L, with a solution volume of 1 L. 1 M sulfuric acid was used to adjust the pH to 6, and the reaction system temperature was set at 40 °C. 2.5 g of the layered lattice iron bifunctional catalyst obtained in Example 4 was put into the 2,4-DCP solution, and the first oscillation was carried out in a shaker at 150 rpm under dark conditions for 90 min. Then 60 mg of 30 wt.% H2O2 was added, and the oscillation was carried out for 0 min to achieve the removal of organic pollutants. The removal efficiency, COD removal rate, and iron dissolution amount were 86.54%, 52.30%, and 0.0018 mg / L, respectively.

[0118] The mixed solution of the layered lattice iron bifunctional catalyst after the reaction was filtered through a 0.22 μm filter membrane, and the surface residual organic matter was washed with deionized water and dried at 60 °C under vacuum conditions. The recovered layered lattice iron bifunctional catalyst was re-put into the pollutant solution to cycle the degradation and removal of organic pollutants. After 100 cycles, the removal efficiency, COD removal rate, and iron dissolution amount were 82.88%, 49.15%, and 0.0022 mg / L, respectively, and the total volume of the polluted object treated this time reached 100 L.

[0119] Comparative Example 1

[0120] The application of the catalyst provided in this comparative example in the degradation and removal of organic pollutants is generally the same as that in Example 8. The main difference is that the catalyst used in this Comparative Example 1 is replaced by loading iron oxide on attapulgite material (the iron content in attapulgite is about 2 wt.%) by the impregnation method [refer to the literature Magnetic Activated-ATP@Fe3O4 Nanocomposite as an Efficient Fenton-Like Heterogeneous Catalyst for Degradation of Ethidium Bromide. Sci. Rep. 7, 6070 (2017).].

[0121] The removal efficiency, COD removal rate, and iron dissolution amount after a single experiment in this comparative example are 68.79%, 37.46%, and 1.3796 mg / L, respectively; after 100 cycles, the removal efficiency, COD removal rate, and iron dissolution amount are 33.17%, 17.65%, and 17.65 mg / L, respectively.

[0122] Table 1

[0123]

Claims

1. A preparation method of a layered lattice iron bifunctional catalyst, characterized in that, It includes the following steps: Step 1: Mix the layered structure material with deionized water evenly to obtain a slurry. Add the slurry to a nucleation reactor and stir vigorously. Then add the stirred slurry back to the nucleation reactor and continue stirring, repeating this process multiple times. Subsequently, collect the slurry and perform centrifugation. The solid material obtained by centrifugation is dried under vacuum to obtain the purified and size-selected material; The layered structure material includes any one or a combination of two of attapulgite containing iron or iron-based hydrotalcite; the relative content of Fe in the layered structure material is 10.83 wt.% to 20.48 wt.%; The parameters of the nucleation reactor are set as follows: the stator-rotor slit width is 0.05 - 0.5 mm, and the rotational speed is 100 - 3000 rpm; Step 2: Calcinate the material obtained in Step 1 at a high temperature for structural evolution to obtain a layered lattice iron bifunctional catalyst; the high-temperature calcination temperature is 150 - 700 °C, the heat preservation time is 1 - 5 h, and the heating rate is 4 - 10 °C / min.

2. The preparation method of the layered lattice iron bifunctional catalyst according to claim 1, characterized in that, The mass ratio of the layered structure material to deionized water is 1:1000 - 1:

100.

3. The preparation method of the layered lattice iron bifunctional catalyst according to claim 1, characterized in that, The mass of the layered structure material in Step 1 is 1 - 25000 g.

4. A layered lattice iron bifunctional catalyst, characterized in that, It is prepared by using the preparation method of the layered lattice iron bifunctional catalyst according to any one of claims 1 - 3.

5. The layered lattice iron bifunctional catalyst according to claim 4, characterized in that, The Zeta potential of the layered lattice iron bifunctional catalyst is -32.26 to 45.16 mV, the specific surface area is 63.97 to 146.98 m 2 / g, and the pore diameter is 13.34 to 26.89 nm.

6. The layered lattice iron bifunctional catalyst according to claim 4, wherein In the described layered lattice iron bifunctional catalyst, the molar ratio of divalent iron to trivalent iron is 0.54 - 1.

94.

7. Application of the layered lattice iron bifunctional catalyst according to any one of claims 4 - 6 in the degradation and removal of organic pollutants.

8. Use of the layered lattice iron bifunctional catalyst according to claim 7 in degrading and removing organic pollutants, characterized in that, The method for degrading and removing organic pollutants includes the following steps: Step S1: Select an organic pollutant and adjust the concentration of the pollutant solution and the pH of the pollutant solution; Step S2: Adjust the temperature of the reaction system; Step S3: Put the layered lattice iron bifunctional catalyst into the pollutant solution, perform the first oscillation, and then add H2O2 for the second oscillation to make the reaction complete, thereby achieving the removal of the organic pollutant.

9. Use of the layered lattice iron bifunctional catalyst according to claim 8 in degrading and removing organic pollutants, characterized in that, In Step S1, the organic pollutant is any one or a mixture of multiple ones among methylene blue, methyl orange, congo red, rhodamine B, tetracycline hydrochloride, doxycycline hydrochloride, ciprofloxacin, phenol, bisphenol A, or 2,4-dichlorophenol; Adjust the concentration of the pollutant solution to 10 - 30000 mg / L, the volume to 0.05 - 2 L, and the pH of the pollutant solution to 2 - 14.

10. Use of the layered lattice iron bifunctional catalyst according to claim 9 in degrading and removing organic pollutants, characterized in that, Use 1 M sulfuric acid or sodium hydroxide to adjust the pH of the pollutant solution.

11. Use of the layered lattice iron bifunctional catalyst according to claim 8 in degrading and removing organic pollutants, characterized in that, In Step S2, the temperature of the reaction system is 20 - 80 °C.

12. Use of the layered lattice iron bifunctional catalyst according to claim 8 in degrading and removing organic pollutants, characterized in that, In Step S3, the first oscillation time is 0 - 120 min; the purity of H2O2 is 10 wt.% - 30 wt.%, and the mass fraction ratio of H2O2 to the layered lattice iron bifunctional catalyst is 1:100 - 1:10; the second oscillation time is 0 - 120 min.

13. Use of the layered lattice iron bifunctional catalyst according to claim 8 in degrading and removing organic pollutants, characterized in that, The method for degrading and removing organic pollutants further includes the recovery of the layered lattice iron bifunctional catalyst. Specifically, the mixed solution of the layered lattice iron bifunctional catalyst after the reaction is filtered through a 0.22 μm filter membrane, and the residual organic matter on the surface is washed with deionized water, and then dried at 60 °C for 6 h under vacuum conditions.

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