A Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve and its preparation method

Abstract

The present invention belongs to the technical field of co-crystalline molecular sieves, and discloses an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve and a preparation method thereof. The preparation method includes S1, preparing a barium slag acidified separation solution A containing trivalent iron ions, aluminum ions, and divalent manganese ions; S2, preparing a reaction solution B using the remaining barium slag containing silicon; S3, preparing a low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve; S4, preparing a high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve. The present invention uses barium slag as a raw material and prepares a high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve by a hydrothermal method, with a high recovery efficiency of barium and no additional polluting products generated. It not only solves the environmental pollution caused by barium slag but also reduces resource waste.

Description

Technical Field

[0001] The present invention relates to the technical field of co-crystalline molecular sieves, and particularly to an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve and a preparation method thereof. Background Art

[0002] As a solid waste inevitably generated during the industrial production of barium carbonate from barite, barium slag not only occupies a large amount of valuable land resources, posing a severe challenge to the balance of the local ecosystem, but also may pollute groundwater, soil and air through percolation and other means, causing a profound and irreversible impact on the environment. Therefore, the treatment of barium slag has always attracted much attention. However, through in-depth exploration of the composition of barium slag, relevant personnel found that barium slag contains rich barium-containing, iron-containing compounds and other associated resources, which endow barium slag with potential recycling value, meaning that they may be transformed into valuable secondary resources and have potential recycling value.

[0003] However, in the current common treatment methods for barium slag, such as ball milling treatment, water-soluble treatment, acidification treatment, etc., the recovery efficiency of barium and the resource utilization rate in barium slag still need to be improved, and the resource waste rate is relatively high; moreover, new pollutants such as organic impurities and insoluble barium salts may be generated during the treatment process, and these pollutants need to be further treated, increasing the environmental burden. Summary of the Invention

[0004] The present invention aims to provide an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve and a preparation method thereof. Using barium slag as a raw material, a high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve is prepared by a hydrothermal method, which has a high recovery efficiency of barium and does not produce additional pollution products. It not only solves the environmental pollution caused by barium slag, but also reduces resource waste, thus solving the problems in the background art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A preparation method of an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve, comprising the following steps:

[0007] S1. Prepare barium slag acidification separation solution A containing ferric ions, aluminum ions and manganese ions

[0008] Wash the silicon-containing barium slag to neutral, then add an acid solution for acidification, stir evenly, take the supernatant, add hydrogen peroxide, and carry out an aging reaction to convert ferrous ions in the supernatant into ferric ions. After the reaction is complete, add manganese chloride powder and aluminum sulfate reagent, and dilute to obtain solution A;

[0009] S2. Prepare reaction solution B using the residue of silicon-containing barium slag

[0010] Take the barium residue left after step S1, wash it until neutral and dry it, then ball-mill and crush the barium residue to obtain barium residue particles, and then soak them in a strong alkali solution. After the aging reaction ends, take the supernatant to obtain reaction solution B.

[0011] S3. Prepare low-sodium Fe-Mn-ZSM5 / 11 barium residue-based co-crystalline zeolite

[0012] Disperse the ZSM5 / 11 zeolite into solution A, raise the temperature to accelerate ion exchange to obtain a C mixed system; after the reaction ends, under stirring, drop the reaction solution B obtained in step S2 into the C mixed system, raise the temperature for pre-crystallization, cool and transfer it to a reaction kettle for reaction to obtain a mixed system D; filter the mixed system D, and after washing, obtain low-sodium Fe-Mn-ZSM5 / 11 barium residue-based co-crystalline zeolite.

[0013] S4. Prepare high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium residue-based co-crystalline zeolite

[0014] Add iron-containing and manganese-containing solutions to the low-sodium Fe-Mn-ZSM5 / 11 barium residue-based co-crystalline zeolite obtained in step S3, raise the temperature for ion exchange, then wash, dry and calcine to prepare high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium residue-based co-crystalline zeolite.

[0015] Further, in S1, the acid solution is sulfuric acid with a concentration of 0.25 mol·L -1 , and the volume of sulfuric acid and the mass of barium residue are in accordance with 100 ml of sulfuric acid acidifying 10 g of barium residue; the concentration of hydrogen peroxide is 30%, and the volume ratio of sulfuric acid to hydrogen peroxide is 1:40; the aging time is 3 - 5 h.

[0016] Further, the molar ratio of each component in the prepared solution A is Fe 3+ : Mn 2+ : Al 3+ is 2:1:2 - 20.

[0017] Further, in S2, the ball-milling time is 5 - 8 h, and the ball-to-material ratio is 1:10. The particle size of the barium residue particles after ball-milling and crushing is 5 - 20 μm; the strong alkali solution is sodium hydroxide with a concentration of 0.25 mol·L -1 .

[0018] Further, in the prepared reaction solution B, the molar ratio of each component to Al 3+ in the solution A in step S1 is SiO2:NaOH:Al 3+ : H2O is 10 - 30:5 - 15:0.2 - 1:100 - 600.

[0019] Further, in S3, after the mixed system D is filtered, it is washed successively with water and an acidic solution by suction filtration to remove sodium.

[0020] Further, the acidic solution is an ammonium sulfate solution or an ammonium chloride solution with a mass fraction of 10 - 15%.

[0021] Further, in S3, the temperatures for heating up to accelerate ion exchange and heating up for pre-crystallization are both 75 - 85°C, and the time for pre-crystallization is 5 h.

[0022] Further, in S3, during the process of dispersing the ZSM5 / 11 molecular sieve into solution A, the mass of the ZSM5 / 11 molecular sieve is 0.2 - 2 times the mass of the aluminum source in solution A in step S1; wherein, the mass of the aluminum source is calculated according to the molecular weight of Al2O3.

[0023] Further, in S4, before adding the iron-containing and manganese-containing solutions to the low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve, first, an inorganic iron salt, manganese tetrachloride, water, and the low-sodium Fe-Mn-ZSM5 / 11 obtained in step S3 are mixed and slurried according to a mass ratio of 0.3 - 1:0.3 - 1:4 - 10:1, and exchanged at 75 - 85°C for 1 - 10 hours, then filtered and washed to obtain a low-sodium, high-iron, and high-manganese Fe-Mn-ZSM5 / 11 molecular sieve filter cake.

[0024] Further, in S4, the temperature for heating up to conduct ion exchange is 75 - 85°C, and the solution containing iron and manganese is a mixed solution of an inorganic iron salt, manganese chloride, and water.

[0025] The Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve prepared by the above method for preparing an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve.

[0026] The principle and beneficial effects of the technical solution are as follows:

[0027] 1. For the method for preparing an Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve provided by the present invention, metal ions such as iron and aluminum in the barium slag are dissolved out through an acidification reaction, and hydrogen peroxide is used to oxidize divalent iron ions to trivalent iron ions to increase the stability and catalytic activity of the iron ions; manganese chloride powder and aluminum sulfate reagent are added to provide a manganese source and an aluminum source; through ball milling and soaking in strong alkali, silicon in the barium slag residue is dissolved out to form a sodium silicate solution, providing a silicon source for subsequent molecular sieve synthesis.

[0028] 2. A preparation method of Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve provided by the present invention uses ZSM5 / 11 molecular sieve as a carrier. By ion exchange, iron, manganese, and aluminum ions in solution A are introduced into its framework or pores, which can change the catalytic performance of the molecular sieve. Solution B is dropped into the C mixed system, and through hydrothermal synthesis, the silicon source is combined with metal ions. Through ion exchange, more iron and manganese are introduced into the molecular sieve to further improve its catalytic activity.

[0029] 3. A preparation method of Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve provided by the present invention uses barium slag as a raw material and converts it into a valuable molecular sieve through chemical treatment, realizing the effective recovery and reuse of resources. Using barium slag as a raw material reduces the environmental pollution caused by barium slag, and at the same time, the preparation process of the molecular sieve is environmentally friendly and will not cause secondary pollution. And by introducing metal ions such as iron, manganese, and aluminum, the catalytic performance of the molecular sieve is changed.

[0030] In summary, the present invention uses barium slag containing iron compounds, aluminum compounds, and manganese compounds as a raw material to prepare Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve. After the zeolite molecular sieve is ion-exchanged with iron ions, the number, size, and position of cations change. For example, when high-valent cations exchange low-valent cations, the number of cations in the zeolite molecular sieve decreases. On the one hand, this causes a certain blockage of the pores, reduces the effective pore diameter, and enhances selective adsorption. On the other hand, the surface of the zeolite molecular sieve modified with manganese has strong acid centers, and there is a strong Coulomb field in the crystal pores to play a polarization role. These characteristics increase the catalytic performance of the Fe-Mn-ZSM5 / 11 barium slag-based molecular sieve, which not only solves the environmental pollution caused by barium slag but also increases the catalytic performance of the Fe-Mn-ZSM5 / 11 molecular sieve modified by barium slag, realizing the recycling of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a flowchart of a preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve of the present invention;

[0032] Figure 2 is an XRD diagram of ZSM-5 / 11 molecular sieve and the barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve prepared by the present invention;

[0033] Figure 3 is an XPS spectrum of the barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve prepared by the present invention;

[0034] Figure 4 is an SEM diagram of ZSM-5 / ZSM-11 molecular sieve and the barium slag-based Fe-Mn-ZSM5 / ZSM-11 co-crystalline molecular sieve prepared by the present invention;

[0035] In the figure, (a) is the SEM image of ZSM-5, (b) is the SEM image of ZSM-11; (c) is the SEM image of Fe-Mn-ZSM5, and (d) is the SEM image of Fe-Mn-ZSM-11;

[0036] Figure 5 This is the EDX mapping image of the barium slag-based Fe-Mn-ZSM5 / ZSM-11 co-crystalline molecular sieve prepared by the present invention;

[0037] Figure 6 This is the TCD diagram of the barium slag-based Fe-Mn-ZSM5 / ZSM-11 co-crystalline molecular sieve and ZSM-5 / ZSM-11 prepared by the present invention. Specific Embodiments

[0038] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments:

[0039] As Figure 1 shown, a preparation method of a barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve includes the following steps:

[0040] S1: Prepare a barium slag acidified separation solution A containing trivalent iron ions, aluminum ions, and divalent manganese ions

[0041] Wash 10.0 g of barium slag to neutral, add 100 ml of sulfuric acid with a concentration of 0.25 mol·L -1 for acidification. After stirring evenly, take the supernatant, add 2.5 ml of hydrogen peroxide with a concentration of 30%, carry out an aging reaction for 4 h to convert divalent iron ions in the supernatant into trivalent iron ions. After the reaction is complete, add 0.5 g of manganese chloride powder and 2 g of aluminum sulfate powder, and then dilute the mixture to 500 ml to obtain solution A, so that the molar ratio of each component in solution A is Fe 3+ : Mn 2+ : Al 3+ = 2:1:2 - 20;

[0042] S2: Prepare a high-concentration sodium silicate solution B using the barium slag residue containing silicon

[0043] Wash the barium slag residue after taking the supernatant in step S1 to neutral, dry it, ball-mill and break the barium slag residue. The ball-milling time is 6 h, and the ball-to-material ratio is 1:10 to obtain barium slag residue particles with a particle size of 5 - 20 μm; then soak it with 100 ml of sodium hydroxide solution with a concentration of 0.25 mol·L -1 , carry out an aging reaction for about 5 h, and take the supernatant to obtain sodium silicate solution B;

[0044] S3: Preparation of low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve

[0045] Disperse the ZSM5 / 11 molecular sieve into solution A, heat it to 80 °C to accelerate ion exchange to obtain a C mixed system; after the reaction ends, while stirring, drip 500 ml of the sodium silicate solution B obtained in step S2 into the C mixed system, heat it to 80 °C for pre-crystallization for 3 h, then cool and transfer it to a reaction kettle to react at 180 °C for 24 h to obtain a mixed system D; filter the mixed system D, wash it with water 8 - 10 times, and wash it with a 15% mass fraction ammonium chloride acidic solution 2 - 3 times to remove sodium, and obtain 2.4 g of low-sodium Fe-Mn-ZSM5 / 11 molecular sieve through suction filtration washing;

[0046] S4: Preparation of high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve

[0047] Mix 0.5 g of inorganic iron salt, 0.25 g of manganese dichloride, 150 g of water and 2.4 g of the low-sodium Fe-Mn-ZSM5 / 11 molecular sieve obtained in step S3 to make a homogeneous slurry, exchange at 80 °C for 5 h, filter and wash to obtain 2.8 g of a low-sodium, high-iron and high-manganese Fe-Mn-ZSM5 / 11 molecular sieve filter cake; then dry the obtained low-sodium, high-iron and high-manganese Fe-Mn-ZSM5 / 11 molecular sieve filter cake and calcine it at 500 °C for 3 h to obtain a low-sodium, high-iron and high-manganese molecular sieve with high iron and manganese content.

[0048] As Figure 2 shown, the diffraction peaks of the barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve prepared by the above method can match the standard cards ZSM-5 (PDF#42 - 0003) and ZSM-11 (PDF#42 - 0022) and there are no impurity peaks, indicating that the purity of the barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve prepared by this method is relatively high.

[0049] As Figure 3 shown, obvious Fe 2p, Mn 2p, O 1s, C 1s, Si 2p, and Al 2p orbits are found at binding energies of 711.27 eV, 641.84 eV, 532.03 eV, 284.81 eV, 102.87 eV, and 74.46 eV. Therefore, it can be judged that the barium slag-based Fe-Mn-ZSM5 / 11 co-crystalline molecular sieve prepared by the above method has Si-Fe-O and Si-Mn-O chemical bonds.

[0050] As Figure 4As shown, it can be seen from Figures (a) and (b) that the ZSM-5 / ZSM-11 molecular sieve presents a regular cuboid structure, with a length of about 2 - 5 microns and a width of about 1 - 1.5 microns. It can be seen from Figures (c) and (d) that for the molecular sieve doped with iron and manganese elements, its surface becomes very rough, which makes gas adsorption and subsequent improvement of catalytic performance possible.

[0051] As Figure 5 shown, in addition to the basic silicon and aluminum elements, the surface of the barium slag-based Fe-Mn-ZSM5 / ZSM-11 co-crystalline molecular sieve prepared by the above method is also enriched with a large amount of iron and manganese elements. These elements are evenly distributed on the surface. This is consistent with Figure 3 the conclusion of the XPS spectrum.

[0052] As Figure 6 shown, it is the desorption of NO by the barium slag-based Fe-Mn-ZSM5 / ZSM-11 co-crystalline molecular sieve prepared by the above method, which is related to its temperature trend. When the temperature is lower than 300 °C, the desorption of Fe-Mn-ZSM5 / ZSM-11 is significantly higher than that of ZSM-5 / ZSM-11. This can also indirectly reflect that Fe-Mn-ZSM5 / ZSM-11 has better adsorption of NO.

[0053] In summary, the present invention uses barium slag containing iron compounds, aluminum compounds and manganese compounds as raw materials to prepare Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve. After the zeolite molecular sieve is ion-exchanged with iron ions, the number, size and position of cations change. For example, when a high-valence cation exchanges a low-valence cation, the number of cations in the zeolite molecular sieve decreases. On the one hand, this causes a certain blockage of the pores, reducing the effective pore size and enhancing the selective adsorption. On the other hand, the surface of the zeolite molecular sieve modified with manganese has strong acid centers, and there is a strong Coulomb field in the crystal pores to play a polarization role. These characteristics increase the catalytic performance of the Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve, which not only solves the environmental pollution caused by barium slag, but also increases the catalytic performance of the Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve modified with barium slag, realizing the recycling of resources.

[0054] The above are only the embodiments of the present invention. Specific technical solutions or common knowledge such as well-known characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the implementation effect of the present invention and the practicability of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. A preparation method of Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve, characterized in that, It includes the following steps: S1. Prepare barium slag acidification separation solution A containing ferric ions, aluminum ions and manganous ions Wash the silicon-containing barium slag to neutral, then add an acid solution for acidification. After stirring evenly, take the supernatant, add hydrogen peroxide, and carry out an aging reaction to convert the ferrous ions in the supernatant into ferric ions. After the reaction is complete, add manganese tetrachloride powder and aluminum sulfate reagent, and dilute to obtain solution A; The molar ratio of each component in the prepared solution A is Fe 3+ :Mn 2+ :Al 3+ 2:1:2~20; S2. Prepare reaction solution B using the residue of silicon-containing barium slag Take the barium slag residue in step S1, wash it to neutral and dry it, then ball-mill and break the barium slag residue to obtain barium slag residue particles, and then soak them in a strong alkali solution. After the aging reaction is completed, take the supernatant to obtain reaction solution B; S3. Prepare low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve Disperse ZSM5 / 11 molecular sieve into solution A, and raise the temperature to accelerate ion exchange to obtain a C mixed system; after the reaction is completed, under stirring, drop the reaction solution B obtained in step S2 into the C mixed system, raise the temperature for pre-crystallization, cool and transfer it to a reaction kettle for reaction to obtain a mixed system D; filter the mixed system D, and after washing, obtain a low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve; During the process of dispersing ZSM5 / 11 molecular sieve into solution A, the mass of ZSM5 / 11 molecular sieve is 0.2-2 times the mass of the aluminum source in solution A in step S1; wherein, the mass of the aluminum source is calculated according to the molecular weight of Al2O3; S4. Prepare high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve Add iron- and manganese-containing solutions to the low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve obtained in step S3, raise the temperature for ion exchange, and then wash, dry and calcine to prepare a high-iron and high-manganese Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve.

2. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve according to claim 1, characterized in that, In S1, the acid solution is sulfuric acid with a concentration of 0.25 mol·L -1 , and the volume of sulfuric acid and the mass of barium residue are in accordance with 100 ml of sulfuric acid for acidifying 10 g of barium residue; the concentration of hydrogen peroxide is 30%, and the volume ratio of sulfuric acid to hydrogen peroxide is 1:40; the aging time is 3 - 5 h.

3. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve according to claim 1, characterized in that, In S2, the ball milling time is 5 - 8 h, the ball-to-material ratio is 1:10, and the particle size of the remaining barium slag particles after ball milling and crushing is 5 - 20 μm; the strong alkali solution is sodium hydroxide with a concentration of 0.25 mol·L -1 .

4. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve according to claim 3, characterized in that, In the prepared reaction solution B, the molar ratios of the components to Al in the solution A of step S1 are as follows: 3+ SiO2:NaOH:Al 3+ :H2O is 10-30:5-15:0.2-1:100-600.

5. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve according to claim 1, characterized in that, In S3, after filtering the mixed system D, wash it successively with water and an acidic solution by suction filtration to remove sodium.

6. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve according to claim 5, characterized in that, The acidic solution is an ammonium sulfate solution or ammonium chloride solution with a mass fraction of 10-15%.

7. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve according to claim 1, characterized in that, In S3, the temperature for accelerating ion exchange and the temperature for pre-crystallization by raising the temperature are both 75-85°C, and the pre-crystallization time is 5h.

8. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve according to claim 1, characterized in that, In S4, before adding the iron- and manganese-containing solutions to the low-sodium Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve, first mix and beat the inorganic iron salt, manganese tetrachloride, water and the low-sodium Fe-Mn-ZSM5 / 11 obtained in step S3 according to a mass ratio of 0.3-1:0.3-1:4-10:1, and exchange at 75-85°C for 1-10 hours, filter and wash to obtain a low-sodium, high-iron, high-manganese Fe-Mn-ZSM5 / 11 molecular sieve filter cake.

9. The preparation method of a Fe-Mn-ZSM5 / 11 barium slag-based co-crystallized molecular sieve according to claim 1, characterized in that, In S4, the temperature for ion exchange by raising the temperature is 75-85°C, and the iron- and manganese-containing solution is a mixed solution of inorganic iron salt, manganese tetrachloride and water.

10. The Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve prepared by the preparation method of the Fe-Mn-ZSM5 / 11 barium slag-based co-crystalline molecular sieve according to any one of claims 1-9.

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