A hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material, a preparation method and application thereof

Abstract

The application discloses a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material and a preparation method and application thereof, and the catalytic fiber material takes a PAN fiber as a carrier, takes MOF / MOF material formed by Ce-UiO-66 and ZIF-8 as an active component, and adopts pentafluorobenzene to modify the surface of the active component. The method adopts a special pore channel chip to control the hierarchical multi-layer synthesis of the active component, takes pentafluorobenzene as a surface modifier and an acid site intensifier, and combines micro-fluid electrospinning and reaction self-heating to one-step synthesize the Ce-UiO-66 / ZIF-8@PAN catalytic fiber material. The catalyst synthesized by the method has a hierarchical multi-layer MOF / MOF structure, strong hydrophobicity and large specific surface area, and can efficiently and stably realize the denitration target of non-electric industry low-temperature flue gas working conditions.

Description

TECHNICAL FIELD

[0001] The application relates to a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material, and belongs to the field of industrial flue gas purification in the non-electricity industry. BACKGROUND

[0002] As the most commonly used NO x The technical core of the NH3-SCR method is the development of a new type of denitration catalyst, and at present, commercial catalysts for flue gas denitration of fixed sources mainly include vanadium-based catalysts and rare earth-based catalysts. However, commercial vanadium-based catalysts still have some unavoidable defects, such as poor low-temperature activity, easy volatility of V2O5 and biological toxicity, which seriously hinder their further development in practical applications. The denitration catalyst with Ce and other rare earth elements as active components can not only effectively reduce NO x Pollution of the atmosphere, and can also avoid secondary pollution of the environment by toxic elements V, but rare earth-based catalysts still face problems such as insufficient activity at low temperatures.

[0003] In existing low-temperature denitration patents, patent CN202110032477.8 mixes a molecular sieve acid catalyst with a transition metal oxide by grinding, so that the oxidation-reduction catalyst and the acid catalyst can fully contact, which can effectively increase the acidity of the oxidation-reduction catalyst, and at the same time, will not affect the oxidation-reduction performance of the catalyst itself due to chemical reaction, so that the catalyst has strong resistance to ammonium nitrate poisoning at low temperatures. Patent CN202011527738.5 discloses a low-temperature denitration catalyst and a preparation method thereof. The low-temperature denitration catalyst comprises a cordierite carrier and an active component coated on the carrier, and the active component mainly comprises V2O5, MoO3, SiO2, TiO2 and phosphate ions. The obtained catalyst has good low-temperature catalytic activity and sulfur resistance. Patent CN202011289497.5 discloses a method for preparing a low-temperature denitration catalyst from manganese ore. The method uses manganese ore as the main raw material to prepare a low-temperature denitration catalyst, which comprises the steps of crushing, grinding, component adjustment, mixing, molding, drying and calcination, realizes high-value utilization of manganese ore, and reduces the production cost of the low-temperature denitration catalyst. Although the above catalysts exhibit high-efficiency low-temperature denitration activity to some extent, some of them use V or noble metals as active components, resulting in high catalyst cost and being unsuitable for large-scale industrial applications. The other part has complex raw materials and high preparation difficulty, and has insufficient resistance to SO2 and water vapor under complex flue gas conditions in non-electricity industries. SUMMARY

[0004] The application aims at the problem of low catalytic activity of low-temperature denitration catalyst caused by the coexistence of low-temperature flue gas and multiple pollutants such as water and sulfur in the existing non-electricity industry, and proposes a preparation method and application of a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material.

[0005] A hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material, which takes polyacrylonitrile (PAN) fiber as a carrier, a material formed by Ce-UiO-66 and ZIF-8 as an active component, and pentafluorobenzene as a surface modifier of the active component; wherein the mass percentage of the active component is 1-15% based on the mass of the carrier.

[0006] In some preferred technical solutions, the mass percentage of the active component is 2-8% based on the mass of the carrier.

[0007] In the hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material, the mass ratio of Ce-UiO-66 to ZIF-8 is 1:(1-15), and the mass ratio of pentafluorobenzene to the active component is 1:(10-60).

[0008] In some preferred technical solutions, the mass ratio of Ce-UiO-66 to ZIF-8 is 1:(5-10), and the mass ratio of pentafluorobenzene to the active component is 1:(20-40).

[0009] A preparation method of the above-mentioned catalytic fiber material, which is as follows:

[0010] (1) Preparation of PAN carrier spinning solution

[0011] Dissolve PAN in solvent 1 and stir uniformly to obtain PAN spinning solution A;

[0012] (2) Preparation of active component precursor solution

[0013] Dissolve the zinc source and 2-methylimidazole in solvent 1 and stir uniformly to obtain solution B; dissolve cerium salt, formic acid and p-xylylenic acid in solvent 1 and stir uniformly to obtain Ce-UiO-66 precursor solution C; dissolve pentafluorobenzene in solvent 1 and stir uniformly to obtain solution D;

[0014] (3) Preparation of catalytic fiber material

[0015] Inject solutions A, B, C and D into the microchannel of the microfluidic control chip through multiple micro-injection pumps, mix uniformly to obtain a spinning stock solution, and finally perform electrospinning molding through a microfluidic electrospinning machine. After the fiber molding is completed, the hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material is obtained after drying at room temperature.

[0016] In the preparation method, the molecular weight of the PAN in step (1) is 100000-150000; the mass ratio of the PAN to the solvent 1 in the solution A is 1:(10-12.5); and the solvent 1 is N,N-dimethylformamide.

[0017] In the preparation method, the zinc source in step (2) is zinc nitrate hexahydrate; and the mass ratio of the zinc source, 2-methylimidazole and the solvent 1 in the solution B is 1:(2-7):(15-45).

[0018] In step (2), the cerium salt is cerium ammonium nitrate hexahydrate; and the mass ratio of the cerium salt, terephthalic acid, formic acid and the solvent 1 in the solution C is 1:(0.1-0.5):(1-5):(45-105).

[0019] In step (2), the mass ratio of the pentafluorobenzene to the solvent 1 in the solution D is 1:(20-100).

[0020] The solvent 1 is N,N-dimethylformamide.

[0021] In the preparation method, the injection rate of the micro-injection pump in step (3) is 0.1-25 mL / h; and the spinning voltage of the electrostatic spinning machine is 15-25 kV.

[0022] In the preparation method, the micro-pore channel of the microfluidic control chip is provided with a channel for conveying the solution A and a channel for conveying the solution B, both of which are connected to a main pipe, at least two channels for conveying the solution C are also connected to the main pipe, and the output end of the main pipe is connected to a channel for conveying the solution D, so that the mixed solution of the solution at the output end of the main pipe and the solution D is the spinning dope;

[0023] Preferably, the solution A is injected into the main channel, the solution B also enters the main channel to mix with the spinning solution A, and the solution C also enters the channel to react, the reaction is an exothermic reaction, and the released heat is transferred to the main channel to guide the synthesis of ZIF-8, so that the Ce-UiO-66 is loaded on the surface of the ZIF-8 to form a MOF / MOF structure, and then the pentafluorobenzene solution modifies the active components of the MOF / MOF, and finally the spinning dope with uniform mixing is obtained at the tail end of the chip.

[0024] Most preferably, the flow rates of the injection pumps for the solutions A, B, C and D are set to 10-30 mL / h, 1-10 mL / h, 0.5-2 mL / h and 0.01-2 mL / h, respectively.

[0025] In the technical scheme, the catalytic fiber material is applied to the low-temperature flue gas denitrification in non-electricity industries, and the non-electricity industries are the steel industry, the cement industry, the non-ferrous metal smelting industry and the chemical industry.

[0026] The catalyst activity evaluation experiment condition of the application: 0.1g of the fiber material is poured into a quartz tube with an inner diameter of 6mm, and is fixed by quartz wool and iron wire, the quartz tube is placed in a tube furnace, the actual temperature of the catalytic reaction is adjusted by controlling the heating temperature of the tube furnace. The gas composition: NO (500ppm), NH3 (500ppm), O2 (11vol.%), the rest is N2, the total gas flow is 100mL / min, the control temperature is 90-180℃, each 30℃ stays stable for 30min, and the NO concentration is tested by Laoying 3021 type portable carbon emission monitor. The denitration efficiency of the catalyst is higher than 80% in the temperature range of 90-180℃.

[0027] Beneficial effects:

[0028] (1) The PAN nanofiber has small diameter, high porosity, large specific surface area, good adsorption performance, and good aging resistance under complex flue gas conditions in non-electricity industry. Since the pore diameter of the overall formed catalytic material is smaller than that of the traditional fiber, the catalytic material can effectively filter the micrometer-sized particulate matters in the flue gas, and the dust resistance of the catalytic material is improved.

[0029] (2) Ce has an unfilled 4f electron layer structure, and the Ce element in Ce-UiO-66 forms Ce 3+ / Ce 4+ Coexistence state, accompanied by the generation of oxygen vacancies, the rapid conversion between Ce 3+ / Ce 4+ brings more free electrons and promotes the adsorption and activation of molecular oxygen, improves the oxygen storage capacity and oxidation activity of the catalytic material, and effectively ensures the redox capacity of the catalytic material.

[0030] (3) ZIF-8 has high porosity, large specific surface area and excellent adsorption performance. First, the combination strength and loading effect of Ce-UiO-66 and its surface are effectively improved, the layered MOF combination structure formed exposes the Ce-UiO-66 with higher catalytic activity on the outer layer, and the ZIF-8 with higher adsorption capacity on the inner layer is enhanced, so that the adsorption effect of the catalytic material on the denitration reactants such as NO, NH3 and O2 is improved, and the overall catalytic performance is improved; at the same time, ZIF-8 has strong stability, can maintain the structure integrity under the conditions of containing water and 180℃ flue gas temperature, the loss of active components of the catalyst is less, and the long-term operation stability of the catalyst is strong.

[0031] (4) The advantages of the surface modification of pentafluorobenzene mainly include the following two aspects. First, the increase of the fluorine content on the surface of the MOF material can enhance the hydrophobicity of the material, and improve the durability of the catalytic material in the water-containing environment. Second, the electron-rich fluorine atoms on the pentafluorobenzene group can act as Lewis basic sites, thereby promoting the adsorption of NO to the surface of the catalyst and improving the NO removal efficiency of the catalytic material.

[0032] (5) Based on a special chip Figure 1 The microfluidic electrospinning technology of the channel enables the hierarchical synthesis of catalyst active components and efficient mixing with the support solution. Following the chip channel sequence, the ZIF-8 precursor solution is directly mixed with the PAN support solution. Outside the ZIF-8 synthesis channel is the Ce-UiO-66 synthesis channel. During Ce-UiO-66 synthesis, the solution itself spontaneously and rapidly generates heat, providing heating conditions for ZIF-8 synthesis. This section consumes the excess heat spontaneously generated by the system, and under heating conditions, ZIF-8 can be synthesized rapidly and efficiently. The synthesized ZIF-8, after being combined with Ce-UiO-66, is injected through the pentafluorobenzene solution at the tail, ultimately forming a spinning solution with uniformly mixed active components. The catalytic fiber material formed by electrospinning exhibits uniform dispersion of active components and high bonding strength on its surface, reducing the stepwise synthesis process of active components and fiber support to a one-step synthesis, effectively improving the production efficiency of catalytic materials.

[0033] Therefore, the catalyst prepared by this invention can not only achieve efficient removal of nitrogen oxides in flue gas, but also has strong water and dust resistance and excellent stability under complex flue gas conditions in non-power industries. Moreover, the catalyst components are environmentally friendly, the preparation process is simple, the cost is low, and the cost performance is high, making it highly valuable for application and promotion. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the channels of a chip applicable to this invention;

[0035] Figure 2 This is a physical diagram of the chip;

[0036] Figure 3 SEM image of the catalyst material prepared in Example 3;

[0037] Figure 4 The figures show the NO removal performance of the catalytic materials prepared in Examples 1-3 and Comparative Examples 1-3. Detailed Implementation

[0038] The present invention will be further described below with reference to the embodiments. The embodiments are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0039] Example 1

[0040] (1) Preparation of PAN carrier spinning solution

[0041] Take 10.0000 g of polyacrylonitrile (molecular weight 150000) and dissolve it in 100.0000 g of N, N-dimethylformamide at room temperature to obtain PAN spinning solution A, wherein the mass ratio of PAN and DMF is 1:10;

[0042] (2) Preparation of active component precursor solution

[0043] The mass percentage of the active component is 5% based on the mass of the carrier, and the mass ratio of Ce-UiO-66 to ZIF-8 in the active component is 1:8. Take 0.5759 g of zinc nitrate hexahydrate, 2.8793 g of 2-methylimidazole and dissolve them in 11.5172 g of DMF at room temperature to obtain solution B, wherein the mass ratio of zinc salt, 2-methylimidazole and DMF is 1:5:20; take 0.0905 g of cerium ammonium nitrate hexahydrate, 0.0905 g of formic acid and 0.0090 g of terephthalic acid and dissolve them in 4.5236 g of DMF at room temperature to obtain Ce-UiO-66 precursor solution C, wherein the mass ratio of cerium salt, terephthalic acid, formic acid and DMF is 1:0.1:1:50; take 0.0250 g of pentafluorobenzene and dissolve it in 0.5000 g of DMF at room temperature to obtain solution D, wherein the mass ratio of pentafluorobenzene to active component is 1:20.

[0044] (3) Preparation of catalytic fiber material

[0045] Based on the channel chip ( Figure 1 ), solutions A, B, C and D are injected into the microchannel of the microfluidic control chip through multiple micro-injection pumps, wherein the injection pump flow rates of solutions A, B, C and D are set to 20.000 mL / h, 2.303 mL / h, 0.905 mL / h and 0.100 mL / h, respectively, in the order of flow, ZIF-8 synthesis, Ce-UiO-66 synthesis and pentafluorobenzene modification are carried out, and a uniformly mixed spinning stock solution is obtained at the tail end of the chip. Finally, electrospinning is carried out through a microfluidic electrospinning machine, the spinning voltage of the electrospinning machine is 25 kV, and after the fiber forming is completed, it is dried at room temperature to obtain a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material.

[0046] (4) Catalytic activity test

[0047] Take 0.1 g of catalytic fiber material, pour into a quartz tube with an inner diameter of 6 mm, fix with quartz wool and iron wire, place the quartz tube in a tube furnace, adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas composition is: NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), the rest is N2, the total gas flow is 100 mL / min, the control temperature is 90-180℃, and each 30℃ stays stable for 30 min, and the NO concentration is tested by Laoying 3021 type portable carbon emission monitor. The denitration activity of 90℃ catalytic fiber material reaches 87.5% in 5 min, and the denitration efficiency in 120-180℃ interval is 100% in 5 min.

[0048] Example 2

[0049] (1) Preparation of PAN carrier spinning solution

[0050] Take 10.0000 g of polyacrylonitrile (molecular weight 100000) and dissolve it in 125.0000 g of N,N-dimethylformamide to obtain PAN spinning solution A, wherein the mass ratio of PAN and DMF is 1:12.5;

[0051] (2) Preparation of active component precursor solution

[0052] The mass percentage content of active component is 2% based on the mass of the carrier, and the mass ratio of Ce-UiO-66 to ZIF-8 in the active component is 1:5. Take 0.2159 g of zinc nitrate hexahydrate, 0.8638 g of 2-methylimidazole and 8.6379 g of DMF, and stir uniformly at room temperature to obtain solution B, wherein the mass ratio of zinc salt, 2-methylimidazole and DMF is 1:4:40; take 0.0271 g of cerium ammonium nitrate hexahydrate, 0.0543 g of formic acid and 0.0054 g of terephthalic acid and 2.7141 g of DMF, and stir uniformly at room temperature to obtain Ce-UiO-66 precursor solution C, wherein the mass ratio of cerium salt, terephthalic acid, formic acid and DMF is 1:0.2:2:100; take 0.0061 g of pentafluorobenzene and 0.6111 g of DMF, and stir uniformly at room temperature to obtain solution D, wherein the mass ratio of pentafluorobenzene and active component is 1:30.

[0053] (3) Preparation of catalytic fiber material

[0054] Based on the special channel chip Figure 1), by multiple groups of micro-injection pump to inject solution A, B, C, D into the microfluidic control chip micro-channel, wherein, the solution A, B, C, D injection pump flow is set to 25.000 mL / h, 1.728 mL / h, 0.543 mL / h, 0.122 mL / h, respectively, in the order of flow, respectively, for ZIF-8 synthesis, Ce-UiO-66 synthesis, pentafluorobenzene modification, get mixed uniformity of the spinning dope at the end of the chip, finally through the microfluidic electrospinning machine electrospinning forming, electrospinning machine spinning voltage is 15kV, after fiber forming normal temperature drying to get hierarchical multilayer water resistance low temperature rare earth-based denitration catalytic fiber material.

[0055] (4) Catalytic activity test

[0056] Take 0.1g of catalytic fiber material, pour into a quartz tube with an inner diameter of 6mm, fixed with quartz wool and iron mesh, put the quartz tube in the tube furnace, adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The inlet gas composition: NO (500ppm), NH3 (500ppm), O2 (11vol.%), the rest is N2, the total gas flow is 100mL / min, control the temperature at 90-180℃, stay stable for 30min every 30℃, use Laoying 3021 type portable carbon emission monitor to test the concentration of NO. The denitration activity of 90℃ catalytic fiber material reaches 84.5% at 5min, the denitration efficiency of 120-180℃ interval is 100% at 5min.

[0057] Example 3

[0058] (1) Preparation of PAN carrier spinning solution

[0059] Take 10.0000g of polyacrylonitrile (molecular weight 150000) and dissolve it in 100.0000g of N, N-dimethylformamide to get a uniform stirring at room temperature to get PAN spinning solution A, wherein the mass ratio of PAN and DMF is 1:10;

[0060] (2) Preparation of active component precursor solution

[0061] The mass percentage of the active component in the carrier is 8%, and the mass ratio of Ce-UiO-66 to ZIF-8 in the active component is 1:10. 0.9423 g of zinc nitrate hexahydrate, 4.7116 g of 2-methylimidazole, and 37.6927 g of DMF are stirred uniformly at room temperature to obtain solution B, wherein the mass ratio of zinc salt, 2-methylimidazole, and DMF is 1:5:40; 0.1184 g of cerium ammonium nitrate hexahydrate, 0.1184 g of formic acid, and 0.0118 g of terephthalic acid are dissolved in 5.9218 g of DMF and stirred uniformly at room temperature to obtain Ce-UiO-66 precursor solution C, wherein the mass ratio of cerium salt, terephthalic acid, formic acid, and DMF is 1:0.1:1:50; 0.0200 g of pentafluorobenzene is dissolved in 1.0000 g of DMF and stirred uniformly at room temperature to obtain solution D, wherein the mass ratio of pentafluorobenzene to the active component is 1:40.

[0062] (3) Preparation of catalytic fiber material

[0063] Based on the special channel chip, Figure 1 ), solutions A, B, C, and D are injected into the microchannel of the microfluidic control chip through multiple micro-injection pumps, wherein the flow rates of the injection pumps for solutions A, B, C, and D are set to 20.000 mL / h, 7.539 mL / h, 1.184 mL / h, and 0.200 mL / h, respectively, in the order of flow. ZIF-8 synthesis, Ce-UiO-66 synthesis, and pentafluorobenzene modification are performed in sequence, and a uniformly mixed spinning solution is obtained at the tail end of the chip. Finally, electrospinning is performed through a microfluidic electrospinning machine, and the electrospinning voltage of the electrospinning machine is 25 kV. After fiber formation, normal temperature drying is performed to obtain a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material.

[0064] (4) Catalytic activity test

[0065] 0.1 g of the catalytic fiber material is poured into a quartz tube with an inner diameter of 6 mm, and is fixed with quartz wool and iron mesh. The quartz tube is placed in a tube furnace, and the actual temperature of the catalytic reaction is adjusted by controlling the heating temperature of the tube furnace. The inlet gas components are NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), and the rest is N2, and the total gas flow is 100 mL / min. The control temperature is 90-180℃, and each temperature stays stable for 30 min. The Laoying 3021 portable carbon emission monitor is used to test the NO concentration. The denitration activity of the catalytic fiber material at 90℃ reaches 93.4% in 5 min, and the denitration efficiency in the range of 120-180℃ is 100% in 5 min.

[0066] Comparative Example 1

[0067] (1) Preparation of active component precursor solution

[0068] Except that the Ce-UiO-66 precursor solution is not added in the active component precursor solution, other conditions are the same as example 1;

[0069] (2) Catalytic activity test

[0070] Take 0.1 g of the catalytic fiber material, pour it into a quartz tube with an inner diameter of 6 mm, fix it with quartz wool and iron wire, place the quartz tube in a tube furnace, and adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas composition is: NO (500 ppm), NH3(500 ppm), O2(11 vol.%), and the rest is N2, the total gas flow is 100 mL / min, the control temperature is 90-180℃, and each 30℃ stays stable for 30 min, and the NO concentration is tested by Laoying 3021 type portable carbon emission monitor. The denitration activity of the catalytic fiber material at 90℃ reaches 50.7% in 5 min, and the denitration efficiency at 180℃ is 60.3% in 5 min.

[0071] (3) Comparison effect

[0072] Compared with example 1, the Ce-UiO-66 precursor solution is not added in the preparation of the active component precursor solution, forming a single ZIF-8 supported on PAN fiber catalytic fiber material, losing the strong redox ability of the active component Ce-UiO-66, resulting in a significant decrease in NO removal performance.

[0073] Comparative example 2

[0074] (1) Preparation of catalytic fiber material

[0075] Except that the carrier and active component are not formed by microfluidic electrospinning in one step during the preparation of the catalytic fiber material, but are combined by immersion after being formed in steps, other conditions are the same as example 2;

[0076] (2) Catalytic activity test

[0077] Take 0.1 g of the catalytic fiber material, pour it into a quartz tube with an inner diameter of 6 mm, fix it with quartz wool and iron wire, place the quartz tube in a tube furnace, and adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas composition is: NO (500 ppm), NH3(500 ppm), O2(11 vol.%), and the rest is N2, the total gas flow is 100 mL / min, the control temperature is 90-180℃, and each 30℃ stays stable for 30 min, and the NO concentration is tested by Laoying 3021 type portable carbon emission monitor. The denitration activity of the catalytic fiber material at 90℃ reaches 50.7% in 5 min, and the denitration efficiency at 180℃ is 60.3% in 5 min.

[0078] (3) Comparison effect

[0079] Compared with Example 2, the carrier and active component are not formed by microfluidic electrospinning one-step forming, but are formed by step-by-step forming and then impregnated and combined, which results in low combination strength of the MOF material and the fiber carrier, poor loading effect, serious insufficient content of the active component of the fiber material, and serious decline of the denitration efficiency.

[0080] Comparative Example 3

[0081] (1) Preparation of active component precursor solution

[0082] Except that the pentafluorobenzene solution is not added in the active component precursor solution, other conditions are the same as those in Example 3.

[0083] (2) Test of catalytic activity

[0084] 0.1 g of the catalytic fiber material is poured into a quartz tube with an inner diameter of 6 mm, and is fixed by quartz wool and iron wire, and the quartz tube is placed in a tube furnace, and the actual temperature of the catalytic reaction is adjusted by controlling the heating temperature of the tube furnace. The inlet gas components are NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), and the rest is N2, and the total gas flow is 100 mL / min, and the control temperature is 90-180℃, and each 30℃ stays stable for 30 min, and the NO concentration is tested by Laoying 3021 type portable carbon emission monitor. The denitration activity of the catalytic fiber material at 90℃ for 5 min is 54.3%, and the denitration efficiency at 180℃ for 5 min is 68.1%.

[0085] (3) Comparison effect

[0086] Compared with Example 3, the pentafluorobenzene solution is not added in the preparation of the active component precursor solution, the adsorption performance of the catalytic fiber material to the reactant molecules is reduced, and the water resistance is reduced, which results in obvious decline of the NO removal performance.

Claims

1. A hierarchical multi-layered water-resistant low temperature rare earth-based de-NOx catalytic fibrous material, characterized in that: The catalytic fiber material takes polyacrylonitrile (PAN) fiber as a carrier, and a material formed by Ce-UiO-66 and ZIF-8 as an active component, and the surface of the active component is modified by pentafluorobenzene; wherein, the mass percentage of the active component is 1-15% based on the mass of the carrier.

2. The hierarchical multilayered water-resistant low temperature rare earth-based de-NOx catalytic fibrous material according to claim 1, characterized in that: The mass percentage of the active component is 2-8% based on the mass of the carrier.

3. The hierarchical multilayered water-resistant low temperature rare earth-based de-NOx catalytic fibrous material according to claim 1, wherein: The mass ratio of Ce-UiO-66 to ZIF-8 is 1: (1-15), and the mass ratio of pentafluorobenzene to the active component is 1: (10-60).

4. The hierarchical multilayered water-resistant low temperature rare earth-based de-NOx catalytic fibrous material according to claim 3, wherein: The mass ratio of Ce-UiO-66 to ZIF-8 is 1: (5-10), and the mass ratio of pentafluorobenzene to the active component is 1: (20-40).

5. A method of making the catalytic fibrous material of claim 1, comprising: The preparation method of the catalytic fiber material is as follows: ​ (1) Preparation of PAN carrier spinning solution Dissolve PAN in solvent 1 and stir uniformly to obtain PAN spinning solution A; (2) Preparation of active component precursor solution Dissolve the zinc source and 2-methylimidazole in solvent 1 and stir uniformly to obtain solution B; dissolve cerium salt, formic acid and terephthalic acid in solvent 1 and stir uniformly to obtain Ce-UiO-66 precursor solution C; dissolve pentafluorobenzene in solvent 1 and stir uniformly to obtain solution D; (3) Preparation of catalytic fiber material Inject solutions A, B, C and D into the microchannel of the microfluidic control chip through multiple micro-injection pumps to mix uniformly to obtain a spinning stock solution, and finally perform electrospinning molding through a microfluidic electrospinning machine. After the fiber molding is completed, dry at room temperature to obtain a hierarchical multi-layer water-resistant low-temperature rare earth-based denitration catalytic fiber material.

6. The method of claim 5, wherein: The molecular weight of the PAN in step (1) is 100000-150000; the mass ratio of PAN to solvent 1 in solution A is 1:(10-12.5); the solvent 1 is N, N dimethylformamide.

7. The method of claim 5, wherein: The zinc source in step (2) is zinc nitrate hexahydrate, and the mass ratio of the zinc source, 2-methylimidazole and solvent 1 in solution B is 1: (2-7): (15-45); The cerium salt in step (2) is cerium ammonium nitrate hexahydrate, and the mass ratio of the cerium salt, terephthalic acid, formic acid and solvent 1 in solution C is 1: (0.1-0.5): (1-5): (45-105); The mass ratio of pentafluorobenzene to solvent 1 in solution D in step (2) is 1: (20-100); The solvent 1 is N, N dimethylformamide.

8. The method of claim 5, wherein: The injection rate of the micro-injection pump in step (3) is 0.1-25 mL / h; and the spinning voltage of the electrospinning machine is 15-25 kV.

9. The method of claim 5, wherein: In step (3), the microfluidic control chip microchannel is provided with a channel for conveying solution A and a channel for conveying solution B, both of which are connected to a total pipe. At least two solution C conveying pipes are also connected to the total pipe, and the output end of the total pipe is connected to a solution D conveying pipe. Therefore, the mixed solution of the solution at the output end of the total pipe and solution D is the spinning stock solution.

10. The method of claim 9, wherein: Solution A is injected into the main channel, solution B is also injected into the main channel to mix with spinning solution A, and after mixing, solution C is also injected into the channel to react. This reaction is an exothermic reaction, and the released heat is transferred to the main channel to guide the synthesis of ZIF-8, so that Ce-UiO-66 is loaded on the surface of ZIF-8 to form a MOF / MOF structure. Subsequently, pentafluorobenzene solution modifies the MOF / MOF active component, and finally a uniformly mixed spinning stock solution is obtained at the tail end of the chip.

11. The method of claim 9, wherein: The flow rates of the solution A, B, C and D injection pumps are set to be 10-30 mL / h, 1-10 mL / h, 0.5-2 mL / h and 0.01-2 mL / h respectively.

12. The use of the catalytic fiber material according to claim 1 in the non-electricity industry low-temperature flue gas denitration, wherein the non-electricity industry is the steel industry, the cement industry, the non-ferrous metal smelting industry and the chemical industry.

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