Gold-containing composite film with sulfur resistance and method of making and use thereof

Abstract

This invention relates to the field of palladium-based alloy materials, and discloses a gold-containing composite membrane with sulfur resistance, its preparation method, and its applications. The composite membrane comprises a composite palladium-based alloy material and, sequentially, hydrophobic groups modified with a silica-alumina molecular sieve and VIB metal oxides attached to the surface of the composite palladium-based alloy material. The composite palladium-based alloy material contains Pd, Cu, and Au, with a molar ratio of Pd, Cu, and Au of 100:(58-95):(9-37). The composite palladium-based alloy material has a face-centered cubic close-packed crystal structure with a lattice parameter k of 0.4098-4286 nm. The composite membrane of this invention exhibits high structural stability and sulfur resistance, and can be applied to the hydrogen separation and purification process after reforming in industrial hydrogen-rich and sulfur- and acidic gas fields. It can obtain high-purity hydrogen and a high hydrogen recovery rate, and has a long service life.

Description

Technical Field

[0001] This invention relates to the field of palladium-based alloy materials, specifically to a gold-containing composite film with sulfur resistance, its preparation method, and its applications. Background Technology

[0002] Compared to hydrogen separation and purification technologies such as pressure swing adsorption (PSA) and cryogenic distillation, membrane separation technology has the advantage of completely removing trace impurities such as N2, Ar, He, and CO2 remaining in hydrogen. Theoretically, dense palladium membranes can achieve 100% selectivity for hydrogen, corresponding to 100% hydrogen purity—a purity standard difficult to achieve with other separation technologies. Therefore, palladium membrane separation technology is a highly promising hydrogen separation and purification technology. However, palladium or palladium alloy membranes form hydrides when in contact with H2 at low temperatures, causing "hydrogen embrittlement," which damages the integrity and density of the pure palladium or palladium alloy membrane. At high temperatures, the surface grains of the palladium membrane rearrange and sinter, leading to pinholes and defects, and even membrane rupture. Therefore, to ensure the long-term stability of the palladium membrane, a suitable and stable operating temperature must be provided; the suitable operating temperature for palladium membranes is 350-500℃. Meanwhile, when palladium membrane separation technology is applied to the separation of industrially abundant hydrogen or the separation and purification of hydrogen produced from reforming in sulfur-containing gas fields, trace amounts of hydrogen sulfide, methyl sulfide, and other sulfur compounds are more easily adsorbed and accumulated on the palladium membrane surface than hydrogen gas. Over time, this leads to the formation of Pd4S structures in the bulk phase of the palladium membrane, resulting in a decrease in the mechanical strength of the membrane material and ultimately causing defects in the palladium membrane, affecting its separation efficiency. Therefore, the application of palladium membranes in the separation and purification system of sulfur-containing hydrogen presents the following problems that urgently need to be addressed: 1) After hydrogen is dissolved at low temperatures (<573K), ultrathin palladium membranes are prone to hydrogen embrittlement and cracking due to drastic changes in lattice parameters, making traditional palladium membrane separation technology unsuitable for low-temperature separation environments. 2) As the concentration of sulfur compounds in the system to be separated increases, the separation efficiency decreases due to sulfide poisoning on the palladium membrane surface. The low-temperature environment exacerbates the decrease in the mechanical strength of the palladium membrane and the exposure of defects, ultimately affecting the hydrogen separation and purification efficiency.

[0003] Existing technologies prepare composite modified solutions by mixing palladium nanoparticle suspensions of a certain particle size with MoS2 particles (or by preparing modified solutions using MoS2). Leveraging the high specific surface area and high activity of palladium nanoparticles, these solutions preferentially adsorb and decompose sulfur and chlorine pollutants, enabling stable operation under sulfur and chlorine pollutant atmospheres without affecting the hydrogen permeability of the palladium membrane. These technologies maintain the high hydrogen permeability and selectivity of the palladium membrane and are characterized by simple processes, convenient operation, low investment, and good reproducibility. However, the bonding force between the palladium membrane and MoS2 particles in these existing technologies is insufficient. The composite modified solution prepared by mixing palladium nanoparticle suspensions and MoS2 particles is difficult to uniformly cover the palladium membrane surface and achieve 100% decomposition of sulfur-containing pollutants. Exposed portions of the palladium membrane are often more susceptible to preferential poisoning by sulfides, leading to structural changes and defects. Furthermore, MoS2 has low decomposition efficiency for sulfur-containing compounds, and the decomposed H2S still exists as elemental sulfur on the palladium membrane surface, interacting with the membrane over time and further causing sulfide poisoning. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of hydrogen embrittlement and sulfur poisoning in palladium membranes during hydrogen separation after sulfur-containing hydrogen gas, which leads to changes in crystal structure and affects hydrogen permeability. The invention provides a gold-containing composite membrane with sulfur resistance, its preparation method, and its applications.

[0005] To achieve the above objectives, the first aspect of the present invention provides a gold-containing composite film with sulfur resistance, the composite film comprising a composite palladium-based alloy material and a silica-alumina molecular sieve and a group VIB metal oxide sequentially attached to the surface of the composite palladium-based alloy material with hydrophobic groups, wherein the composite palladium-based alloy material contains Pd, Cu and Au, and the molar ratio of Pd, Cu and Au is 100:(58-95):(9-37), and the crystal structure of the composite palladium-based alloy material is face-centered cubic close-packed with a lattice parameter k of 0.4098-4286 nm.

[0006] A second aspect of the present invention provides a method for preparing a gold-containing composite film with sulfur resistance, the method comprising:

[0007] (1) Pd, Cu and Au are deposited on the support, and then the support with Pd, Cu and Au deposited is alloyed, wherein the molar ratio of Pd, Cu and Au is 100:(58-95):(9-37);

[0008] The alloying process is as follows: in an activating atmosphere, heat treatment is first performed at a temperature of 380-580℃ and a pressure greater than 0.2MPa, and then the temperature is reduced to below 230℃ at a rate greater than 35℃ / min. The gas providing the activating atmosphere may optionally include an alkaline gas.

[0009] (2) The alloyed material is placed in a solution of a precursor containing silicon-aluminum molecular sieve and subjected to hydrothermal crystallization, drying and calcination in sequence to obtain a composite membrane precursor.

[0010] (3) Modify the composite membrane precursor with hydrophobic groups;

[0011] (4) Deposit oxides of group VIB metals on the surface of the product modified with hydrophobic groups obtained in step (3).

[0012] A third aspect of the present invention provides a composite membrane prepared by the method described above.

[0013] The fourth aspect of the present invention provides a composite palladium-based alloy material, which is the composite palladium-based alloy material defined in the first aspect or the product of the alloying treatment described in the second aspect.

[0014] The fifth aspect of this invention provides the application of the composite membrane in hydrogen separation.

[0015] This invention improves the structural stability and sulfur resistance of the palladium-based alloy film by doping it with other metal elements and controlling the quenching conditions to obtain a palladium-based alloy film with a specific crystal structure. Furthermore, this invention adds an in-situ molecular sieve membrane as a protective armor layer on the alloy film surface, which can effectively separate and isolate substances such as H2S and methyl sulfide from the environment, reducing their direct contact with the palladium film. This composite membrane structure allows the palladium film to have a longer service life in sulfur-containing media. Simultaneously, the sulfur-resistant metal oxide nanoparticles on the surface of the molecular sieve membrane can activate and decompose some sulfur-containing compounds, further improving the overall sulfur resistance of the membrane material.

[0016] This invention can be applied to the hydrogen separation and purification process after reforming in industrial hydrogen-rich and sulfur- and acidic gas fields. It is a quiet, efficient, green, and energy-saving hydrogen separation and purification process. It can also be extended to other hydrogen separation and purification applications. The high-purity hydrogen obtained meets the quality requirements of GB / T 37244 and can be directly supplied to hydrogen fuel cell systems. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope image of a composite film prepared according to a preferred embodiment of the present invention;

[0018] Figure 2 These are silicon NMR characterization images of the palladium-based composite film material before and after treatment with a hydrophobic silanizing agent;

[0019] Figure 3 These are scanning electron microscope (SEM) images of the composite palladium-based alloy material in the composite membrane of Example 1 before (a) and after (b) hydrogen separation and purification tests in a hydrogen sulfide atmosphere.

[0020] Figure 4 These are scanning electron microscope (SEM) images of the composite palladium-based alloy material of Example D12 before (a) and after (b) hydrogen separation and purification tests in a hydrogen sulfide atmosphere;

[0021] Figure 5 These are X-ray diffraction patterns of the membrane material before and after hydrogen separation and purification tests in a hydrogen sulfide atmosphere. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The first aspect of the present invention provides a gold-containing composite film with sulfur resistance, the composite film comprising a composite palladium-based alloy material and a silica-alumina molecular sieve and a group VIB metal oxide sequentially attached to the surface of the composite palladium-based alloy material with hydrophobic groups modified thereon, wherein the composite palladium-based alloy material contains Pd, Cu and Au, and the molar ratio of Pd, Cu and Au is 100:(58-95):(9-37), and the crystal structure of the composite palladium-based alloy material is face-centered cubic close-packed with a lattice parameter k of 0.4098-4286 nm.

[0024] In this invention, the molar ratio of Pd, Cu and Au can be 100:58:9, 100:60:10, 100:60:20, 100:60:30, 100:60:37, 100:70:9, 100:80:9, 100:86:9, 100:86:15, 100:86:21, 100:86:37, 100:95:9, 100:95:15, 100:95:37 or any value between the above.

[0025] In this invention, "face-centered cubic close packing" means that the 14 atoms involved in a unit cell belong to 4 layers: with one vertex as layer A, the three face-centered atoms and three vertex atoms adjacent to it belong to layer B, the next 6 atoms belong to layer C, and there is another vertex opposite to the vertex of layer A, which is in the next cycle of layer A.

[0026] In this invention, "lattice parameter k" refers to the physical dimensions of a unit cell in a crystal lattice, representing a fundamental structural parameter of a crystalline material. The lattice parameter k represents the edge length of the unit cell, that is, the edge length of each parallelepiped unit, and it is directly related to the bonding energy between atoms. A unit cell in three-dimensional space generally has three lattice parameters, denoted by a, b, and c. Based on the morphological distribution of the Bravais lattice, in the cubic crystal structure (face-centered cubic close packing) involved in this invention, these three constants are all equal, and therefore can be represented by parameter k. Changes in k reflect changes in the composition, stress state, etc., within the crystal. The lattice parameter k can be determined using X-ray diffraction (XRD) or atomic force microscopy (AFM).

[0027] According to the present invention, preferably, the half-width at half-maximum (WHM) of at least one characteristic peak of 2θ in the range of 5°-90° in the XRD pattern of the composite palladium-based alloy material is less than or equal to 0.1615; more preferably, the half-width at half-maximum (WHM) of all characteristic peaks of 2θ in the range of 5°-90° in the XRD pattern of the composite palladium-based alloy material is less than or equal to 0.1615.

[0028] According to the present invention, preferably, in the XRD pattern of the composite palladium-based alloy material, the full width at half maximum (FWHM) of the characteristic peak at 2θ = 40° ± 1° (i.e., the characteristic peak of crystal plane (110)) is less than or equal to 0.0524 (e.g., 0.0524, 0.05, 0.045, 0.04, 0.035, 0.0349, 0.03, 0.025, 0.02, 0.0175, 0.015, 0.01, and any two of the above points), more preferably 0.03-0.0524, and even more preferably 0.022-0.03, or the FWHM of the characteristic peak at 2θ = 46° ± 1° (i.e., the characteristic peak of crystal plane (111)) is less than or equal to 0.0873 (e.g., 0.0698, 0.01, 0.01, 0.01, and any two of the above points). 6. 0.0524, 0.05, 0.045, 0.04, 0.035, 0.0349, 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points), more preferably 0.036-0.08, even more preferably 0.036-0.06, or the full width at half maximum (FWHM) of the characteristic peak at 2θ = 69° ± 1° (i.e., the characteristic peak of crystal plane (220)) is less than or equal to 0.1222 (e.g., 0.1222, 0.12, 0.11, 0.1, 0.09, 0.0873, 0.08, 0.07, 0.06, 0.0698, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0 The range of 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points), more preferably 0.05-0.09, and even more preferably 0.0526-0.0836, or the full width at half maximum (FWHM) of the characteristic peak at 2θ = 83° ± 1° (i.e., the characteristic peak of the crystal plane (311)) is less than or equal to 0.1396 (e.g., 0.13, 0.1222, 0.12, 0.11, 0.1047, 0.1, 0.09, 0.0873, 0.08, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points). The half-width of the characteristic peak at 2θ = 87° ± 1° (i.e., the characteristic peak of the crystal plane (222)) is less than or equal to 0.1571 (e.g., 0.1571, 0.14, 0.13, 0.12, 0.11, 0.1047, 0.1, 0.09, 0.0873, 0.08, 0.07, 0.06, 0.0524, 0.05, 0.045, 0.04, 0.035, 0.03, 0.025, 0.02, 0.015, 0.01, and any two of the above points), more preferably 0.08-0.13, and more preferably 0.0808-0.093.

[0029] According to the present invention, preferably, the thickness of the composite palladium-based alloy material is 0.5-30 μm (e.g., 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, and any two of the above), more preferably 5-15 μm, and even more preferably 7-10 μm.

[0030] According to the present invention, preferably, the water contact angle of the composite membrane is greater than or equal to 90°, more preferably greater than or equal to 105°, and even more preferably 108-113°.

[0031] According to the present invention, preferably, the composite membrane is a tubular membrane.

[0032] According to the present invention, preferably, the composite membrane further includes a support body, the composite palladium-based alloy material is attached to the support body, and the thickness of the support body is 0.1-20 mm (for example, 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, and any two of the above), preferably 2-5 mm.

[0033] According to the present invention, preferably, the hydrophobic group-modified silica-alumina molecular sieve... 29 In the Si MAS NMR spectrum, the ratio of the peak areas of the peaks with chemical shifts near -113ppm and -103ppm is 6-12 (e.g., 6, 6.5, 7, 7.5, 8, 8.5, 9, 10, 11, 12, and any two of the above), more preferably 6.5-8.5, and even more preferably 7.3-8.3.

[0034] According to the present invention, preferably, the hydrophobic groups in the hydrophobic group-modified silica-alumina molecular sieve are provided by at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, 3-aminopropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, 1-[3-(trimethoxysilyl)propyl]urea, (3-chloropropyl)trimethoxysilane, and 3-chloropropyltriethoxysilane, and more preferably by at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, and 3-aminopropyltrimethoxysilane.

[0035] According to the present invention, preferably, the hydrophobic group-modified silica-alumina molecular sieve is at least one of the following: ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-34, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, SAPO-31, SAPO-34, SAPO-44, RUB-13, MCM-68, Y-type molecular sieve, and mordenite.

[0036] According to the present invention, preferably, the thickness of the hydrophobic group-modified silica-alumina molecular sieve is 2-125 μm (e.g., 2 μm, 10 μm, 15 μm, 18 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 125 μm, and any two of the above), preferably 15-50 μm, and more preferably 15-25 μm.

[0037] According to the present invention, preferably, the silicon-to-aluminum molar ratio of the hydrophobic group-modified silica-alumina molecular sieve is (5-100):1, more preferably (10-40):1; the average particle size is 100-350 nm, more preferably 150-200 nm; the average pore size is 0.35-280 nm, more preferably 0.85-55 nm; and the specific surface area is 75-800 m². 2 / g, preferably 100-550m 2 / g; crystallinity greater than or equal to 90%, preferably 95-99%.

[0038] According to the present invention, preferably, the average particle size of the group VIB metal oxide is 10-750 nm.

[0039] According to the present invention, preferably, the group VIB metal is Mo and / or W (or the oxide of the group VIB metal is MoO2 and / or WO3), but more preferably Mo (or the oxide of the group VIB metal is MoO2).

[0040] According to the present invention, preferably, the content of the group VIB metal oxide is such that the molar ratio between the group VIB metal and Pd is 0.01-0.5 (e.g., 0.01, 0.05, 0.08, 0.1, 0.11, 0.15, 0.2, 0.21, 0.25, 0.3, 0.4, 0.5, and any two of the above), more preferably 0.08-0.21.

[0041] According to the present invention, preferably, the composite membrane has an Eact value of less than or equal to 15, more preferably 12-13.5, and even more preferably 12.3-12.8. act (Hydrogen permeation activation energy, unit: kJ·mol) -1The test method involves measuring the hydrogen permeation rate from 573 K to 773 K under a transmembrane pressure difference of 0.1 MPa, combined with the Arrhenius equation J. H2 =J H2 ° exp(-E act / RT), calculated through measurement, where J H2 It is the hydrogen permeation diffusion rate, J H2 ° is the hydrogen permeation diffusion coefficient, and R is the gas constant. The higher the hydrogen permeation activation energy, the higher the hydrogen mass transfer resistance of the composite membrane material, and the more difficult it is for hydrogen to permeate and diffuse through the composite membrane.

[0042] A second aspect of the present invention provides a method for preparing a gold-containing composite film with sulfur resistance, the method comprising:

[0043] (1) Pd, Cu and Au are deposited on the support, and then the support with Pd, Cu and Au deposited is alloyed, wherein the molar ratio of Pd, Cu and Au is 100:(58-95):(9-37);

[0044] The alloying process is as follows: in an activating atmosphere, heat treatment is first performed at a temperature of 380-580℃ and a pressure greater than 0.2MPa, and then the temperature is reduced to below 230℃ at a rate greater than 35℃ / min. The gas providing the activating atmosphere may optionally include an alkaline gas.

[0045] (2) The alloyed material is placed in a solution of a precursor containing silicon-aluminum molecular sieve and subjected to hydrothermal crystallization, drying and calcination in sequence to obtain a composite membrane precursor.

[0046] (3) Modify the composite membrane precursor with hydrophobic groups;

[0047] (4) Deposit oxides of group VIB metals on the surface of the product modified with hydrophobic groups obtained in step (3).

[0048] The present invention reduces the activation energy of hydrogen permeation of the membrane material by performing heat treatment at a specific temperature and then cooling it at a specific rate, thereby improving the hydrogen permeation efficiency and stability of the membrane material (the half-peak width corresponding to the characteristic peak is small). The use of alkaline gas will further improve the hydrogen permeation and stability of the membrane material.

[0049] According to the present invention, preferably, the alloying treatment is carried out as follows: after treatment in an activating atmosphere at a temperature of 400-500°C and a pressure of 0.24-0.35 MPa for 4-6 hours, the temperature is reduced to 180-230°C at a rate of 40-65°C / min.

[0050] According to the present invention, preferably, the gas providing the activating atmosphere comprises hydrogen and nitrogen, wherein the hydrogen content in the mixture of hydrogen and nitrogen is greater than or equal to 30% by volume, more preferably 31-61% by volume.

[0051] According to the present invention, preferably, the gas providing the activating atmosphere includes hydrogen and alkaline gas; more preferably, the content of alkaline gas in the gas providing the activating atmosphere is greater than or equal to 20% by volume; and even more preferably, it is 22-30% by volume.

[0052] According to the present invention, preferably, the alkaline gas is selected from at least one of ethylenediamine, NH3, PH3 and N2H4.

[0053] According to the present invention, preferably, the total thickness of Pd, Cu and Au deposited on the support is 0.5-30 μm (e.g., 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, and any two of the above), preferably 5-15 μm, and more preferably 7-10 μm.

[0054] According to the present invention, preferably, the thickness of the support is 0.1-20 mm (e.g., 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 15 mm, 20 mm, and any two of the above), preferably 2-5 mm. The support can be provided by materials commonly used in the art that can withstand the operating temperature of the present invention without affecting hydrogen permeability, that is, materials that do not deform or affect hydrogen permeability at the operating temperature of the present invention. To ensure excellent hydrogen permeability and to obtain better mechanical and thermal stability, as well as to reduce the amount of palladium used (reducing costs), preferably, the support is a porous support, which can be selected from at least one of porous ceramics, porous glass, porous metals (such as porous stainless steel), porous quartz, and polymers, more preferably from at least one of porous ceramics, porous metals, and polymers. Generally, the porosity distribution of the support ranges from 15-75%, and the average pore size is 0.05-0.4 μm. To obtain a tubular membrane, the support is preferably a tubular support. The porous ceramic material can be γ-Al₂O₃, with a porosity distribution ranging from 25-66% and an average pore size of 0.12-0.4 μm. The porous stainless steel material can be 316L(Fe₂O₃). 69 Cr 17 Ni 12Mo2 has a porosity ranging from 32% to 71% and an average pore size of 0.08 to 0.36 μm. The polymer material can be polyimide, with a porosity ranging from 15% to 37% and an average pore size of 0.05 to 0.22 μm. The "porosity range" and "average pore size" can both be determined using nitrogen physical adsorption.

[0055] According to the present invention, preferably, the precursor solution of the silicon-aluminum molecular sieve contains a silicon source, an aluminum source, a template agent, and water.

[0056] According to the present invention, preferably, the molar ratio of the silicon source, aluminum source, template agent and water is 100:(1-20):(8-60):(75-2500), and more preferably 100:(2.5-10):(30-60):(80-1200).

[0057] According to the present invention, preferably, the content of template agent in the solution of the precursor containing silica-alumina molecular sieve is 0.25-1.2 mol / L.

[0058] According to the present invention, preferably, the amount of the solution containing the silica-alumina molecular sieve precursor is 0.05-2 ml (e.g., 0.2 ml, 0.25 ml, 0.3 ml, 0.4 ml, 0.5 ml, 0.6 ml, 0.7 ml, 0.8 ml, 0.9 ml, 1 ml, 1.5 ml, 2 ml, and any two of the above) relative to 1 g of the alloyed material, more preferably 0.2-0.3 ml.

[0059] According to the present invention, preferably, the silicon source is at least one of silicate ester, silicate and silicon dioxide, and more preferably selected from at least one of tetrabutyl orthosilicate, tetraethyl orthosilicate, sodium silicate, potassium silicate, silica sol and water glass.

[0060] According to the present invention, preferably, the aluminum source is at least one selected from aluminate, alumina, aluminum salt, aluminum sol and organic aluminum alkoxide, and more preferably selected from at least one selected from sodium aluminate, boehmite, aluminum sulfate, aluminum nitrate and aluminum isopropoxide.

[0061] According to the present invention, preferably, the template agent is at least one of tetraalkylammonium hydroxide, alkylamine and tetraalkylammonium halide, and more preferably selected from at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, triethylamine, hexadecyltrimethylammonium bromide and isopropylamine.

[0062] According to the present invention, preferably, the hydrothermal crystallization method is to first perform aging and then crystallize, wherein the aging conditions include: aging temperature 80-100℃ and aging time 3.5-6.5h; and the crystallization conditions include: crystallization temperature 150-180℃ and crystallization time 48-96h.

[0063] The aging process of the present invention can be carried out under stirring conditions, preferably at a stirring rate of 800-950 rpm.

[0064] The crystallization of the present invention can be carried out under stirring conditions, preferably with an aging stirring rate of 15-30 rpm.

[0065] According to the present invention, preferably, the drying conditions include: a drying temperature of 35-60°C and a drying time of 16-24 hours.

[0066] According to the present invention, preferably, the calcination conditions include: calcination temperature of 550-600℃ and calcination time of 6-8h.

[0067] According to the present invention, preferably, the method of modifying the composite membrane precursor with a hydrophobic group is as follows: the composite membrane precursor is silanized using a silanizing agent.

[0068] According to the present invention, preferably, the amount of the silanizing agent used is 3-9 ml (e.g., 3 ml, 3.5 ml, 4 ml, 4.5 ml, 5 ml, 5.5 ml, 6 ml, 7 ml, 8 ml, 9 ml, and any two of the above) relative to 1 g of the composite membrane precursor, more preferably 4.5-5.5 ml.

[0069] According to the present invention, preferably, the silanizing agent is selected from at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, 3-aminopropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, 1-[3-(trimethoxysilyl)propyl]urea, (3-chloropropyl)trimethoxysilane, and 3-chloropropyltriethoxysilane, and more preferably from at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, and 3-aminopropyltrimethoxysilane. More preferably, the weight-average molecular weight of the polymethylhydrosiloxane is 1000-5000 g / mol, and even more preferably 1700-3200 g / mol.

[0070] According to the present invention, preferably, the conditions for silanization treatment may include: a temperature of 15-75°C, preferably 30-55°C; and a pressure of 10-70 kPa. The silanizing agent may be introduced by a purge gas (which may be N2, a rare gas, CO2, etc.), and the flow rate of the purge gas may be 35-75 ml / min.

[0071] According to the present invention, preferably, the average particle size of the group VIB metal oxide is 10-750 nm (e.g., 10 nm, 50 nm, 100 nm, 150 nm, 155 nm, 175 nm, 185 nm, 195 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 750 nm, and any two of the above), more preferably 150-220 nm.

[0072] According to the present invention, preferably, the deposition amount of the group VIB metal oxide is such that the molar ratio between the group VIB metal and Pd is 0.01-0.5 (e.g., 0.01, 0.05, 0.08, 0.1, 0.11, 0.15, 0.2, 0.21, 0.25, 0.3, 0.4, 0.5, and any two of the above), more preferably 0.08-0.21.

[0073] According to the present invention, preferably, the method for depositing VIB metal oxides on the surface of the hydrophobic group-modified product obtained in step (3) is as follows: the hydrophobic group-modified product obtained in step (3) is placed in a solution containing a VIB metal precursor for hydrothermal reaction. More preferably, the hydrothermal reaction conditions include: a temperature of 150-250°C and a time of 24-40 h.

[0074] In this invention, the concentration of the Group VIB metal element in the solution containing the Group VIB metal precursor is 0.01-0.55 mol / L. The Group VIB metal precursor can be selected from molybdates and / or tungstates, preferably at least one of (NH4)6Mo7O2, sodium tungstate, sodium molybdate, potassium molybdate, and strontium molybdate.

[0075] According to a specific embodiment of the present invention, the solution containing the VIB metal precursor contains (NH4)6Mo7O2, (NH4)2CO3, N2H4 and LiOH in a molar ratio of 1:(1-5):(5-8):(2-5), more preferably, the molar ratio of (NH4)6Mo7O2, (NH4)2CO3, N2H4·H2O and LiOH is 1:(2-3):(5-7.5):(3-4.5).

[0076] A third aspect of the present invention provides a composite membrane prepared by the method described above.

[0077] The fourth aspect of the present invention provides a composite palladium-based alloy material, which is the composite palladium-based alloy material defined in the first aspect or the product of the alloying treatment described in the second aspect.

[0078] The fifth aspect of the present invention provides the application of the composite membrane in hydrogen separation.

[0079] According to the present invention, preferably, the conditions for hydrogen separation include: a transmembrane pressure difference greater than or equal to 0.1 MPa (e.g., 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 1 MPa, 10 MPa, and any two of the above), more preferably 0.5-1 MPa, and a system separation temperature of 100-500°C, more preferably 100-200°C, wherein the transmembrane pressure difference refers to the difference between the pressure on the inner side of the membrane (the side where the feed gas enters) and the pressure on the outer side (the side where hydrogen permeates out).

[0080] The present invention will be described in detail below through examples. In the following examples and comparative examples, the inner surface of the support is sealed with polytetrafluoroethylene (PTFE) material, so molecular sieves, nanoparticles, etc. are selectively loaded only on the outer surface of the support, and the PTFE material is peeled off before application or performance testing.

[0081] Examples D1-D4

[0082] (1) Using a porous stainless steel tube as the support (tubular, inner diameter: 10 mm, outer diameter: 13 mm; average pore size: 0.25 μm, porosity: 65%), the support was first soaked in anhydrous ethanol for 30 minutes to remove surface contaminants such as dust and grease. Then, the surface and inner side of the support were rinsed with deionized water and placed in warm water for vacuum cleaning to remove residual ethanol from the pores. Finally, it was placed in an oven and dried at 423 K for 4 hours. According to Faraday's law, Pd, Cu, and Au atomic molar ratios M were deposited on the support using electroplating, as shown in Table 1. The effective film area was 50 cm². 2 The electroplating process involved using a conductive layer carrier as the working electrode, a platinum electrode (Pd plated), a waveguide with 99.999% copper content (Cu plated), and a ruthenium / titanium oxide (RuO2 / TiO2) electrode (Au plated) as the counter electrode, and a saturated calomel electrode as the reference electrode. The plating solution contained metal ions (Pd...) at 30°C. 2+ Cu 2+ Au 3+The concentration was 0.01-0.1 mol / L. Electroplating experiments were carried out using cyclic voltammetry, with the working voltage range being -0.60V to -0.90V, the scan rate being 0.0075V / s, the scan period being 1000, and the sensitivity being set to 0.0001A / V. Meanwhile, during the electroplating process, a plunger-type constant flow pump was used to add the following solutions to the plating bath at a rate of 1-2 ml / min: 0.05 mol / L ammonium palladium chloride ((NH4)2PdCl4) solution; 0.5-1.5 ml / min: 0.075 mol / L copper nitrate (Cu(NO3)2) solution; 0.25-1 ml / min: 0.01 mol / L chloroauric acid (HAuCl4) solution; 0.1 ml / min: ethylenediamine (EDA, 99%, analytical grade); 0.05 ml / min: disodium ethylenediaminetetraacetate (EDTA-2Na, 99%, analytical grade); and 0.01 ml / min: bipyridine (C... 10 H8N2 (99%, analytical grade). The plating bath was vigorously stirred (1000 r / min) while the above solution was added. Every 30 min of electroplating, the working electrode, cleaned with distilled water, was immersed for 10 min in 0.05 mol / L phosphoric acid (H3PO4) solution and 0.05 mol / L dipotassium hydrogen phosphate (K2HPO4) solution, respectively. After the cyclic voltammetry procedure, the working electrode was treated in distilled water at 95℃ for 15 min before being removed. The Pd, Cu, and Au-deposited support was subjected to high-temperature alloying. The alloying process was as follows: after treatment at temperature T1 and pressure P in an activating atmosphere for a period of time (t); the temperature was then reduced to T2 at a cooling rate V. The activating atmosphere consisted of H2 and N2, with the volume ratio of H2 to N2 equal to R1. The amount of activating atmosphere gas provided ensured that the alloying pressure was P. Detailed parameters are shown in Table 1.

[0083] (2) The alloyed material obtained in step (1) was placed in the precursor solution of ZSM-5 molecular sieve for hydrothermal crystallization (aging and crystallization were performed in sequence), drying and calcination. The molar ratio R2 of silicon source, aluminum source, template agent and water and the conditions of each step are shown in Table 1 to obtain the composite membrane precursor. In the precursor solution of ZSM-5 molecular sieve, tetrapropylammonium hydroxide is used as template agent, tetrabutyl orthosilicate (TEOS) is used as silicon source and sodium aluminate is used as aluminum source. The amount of silicon-aluminum molecular sieve precursor solution used is 0.25 ml relative to 1 g of alloyed material.

[0084] (3) The surface of the composite membrane precursor was silanized using a silanizing agent (Table 1) to obtain the composite membrane. The silanization process was as follows: the composite membrane was silanized with the silanizing agent for 45 min in a chemical vapor deposition furnace under certain temperature, pressure, vacuum and inert purge gas conditions. The silanization conditions were: temperature of 55℃, system pressure of 25 kPa (atmospheric pressure of 101.325 kPa) maintained by a vacuum pump; inert purge gas was N2 with a flow rate of 35-75 ml / min; the silanizing agent was an analytical grade sample, and 5 ml of the sample was measured relative to 1 g of composite membrane precursor and placed in a quartz boat, with the quartz boat located on both sides of the sample.

[0085] (4) Further depositing molybdenum oxide on the product obtained in step (3), specifically: the silanized material is placed in a high-pressure hydrothermal synthesis vessel with PTFE (polytetrafluoroethylene) material as the liner, and a mixture of (NH4)6Mo7O2·4H2O, (NH4)2CO3, N2H4·H2O, and LiOH is added, wherein the molar ratio of the above substances is R3, and the molar concentration of (NH4)6Mo7O2·4H2O is 0.075mol / L. Hydrothermal synthesis is carried out in a rotary oven to obtain a uniform MoO2 nanoparticle layer on the surface of the material.

[0086] Table 1

[0087]

[0088] Example D4

[0089] The procedure was carried out as described in Example D1, except that in step (4): the obtained silanized material was placed in a high-pressure hydrothermal synthesis vessel with PTFE (polytetrafluoroethylene) as the liner, and a mixture of Na2WO4·2H2O, H2O, and HCl was added, wherein the molar ratio of the above substances was 1:50:20, and the concentration of Na2WO4·2H2O was 0.03 mol / L. The mixture was vigorously stirred to form a uniform suspension, and hydrothermally synthesized at 180°C in a rotary oven for 24 hours. A uniform WO3 nanoparticle layer was obtained on the surface of the material.

[0090] Example D5

[0091] The process was carried out in accordance with Example D1, except that the gas providing the activation atmosphere was changed to hydrogen and ammonia, with a volume ratio of 2.5:1, and the treatment time in the activation atmosphere was t = 4h.

[0092] Example D6

[0093] The process was carried out in accordance with Example D1, except that the gas providing the activation atmosphere was changed to hydrogen and hydrazine, with a volume ratio of 3:1, and the treatment time in the activation atmosphere was t = 4.5 h.

[0094] Example D7

[0095] The process was carried out in accordance with Example D1, except that the gas providing the activation atmosphere was changed to hydrogen and phosphine, with a volume ratio of 3.5:1, and the treatment time in the activation atmosphere was t = 4.2 h.

[0096] Example D8

[0097] The process is carried out in accordance with Example D1, except that the gas providing the activating atmosphere is only N2.

[0098] Example D9

[0099] The process is carried out in accordance with Example D1, except that the gas providing the activating atmosphere is only H2.

[0100] Example D10

[0101] The process is carried out in accordance with Example D1, except that the gas providing the activation atmosphere is only argon.

[0102] Example D11

[0103] The process was carried out in accordance with Example D1, except that the gases providing the activation atmosphere were hydrogen and CO2 (volume ratio 1:1).

[0104] Comparative Example D1

[0105] The procedure was carried out in accordance with Example D1, except that the temperature was reduced to T2 at a rate of V = 5°C / min.

[0106] Comparative Example D2

[0107] The process was carried out in accordance with Example D1, except that the alloying temperature T1 = 700°C.

[0108] Comparative Example D3

[0109] The process was carried out in accordance with Example D1, except that the alloying pressure P = 0.1 MPa.

[0110] Comparative Example D4

[0111] The procedure was carried out in accordance with Example D1, except that the molar ratio of Pd, Cu, and Au atoms was M = 100:0.5:0.5.

[0112] Comparative Example D5

[0113] The procedure was carried out in accordance with Example D1, except that the molar ratio of Pd, Cu and Au atoms was M = 100:500:500.

[0114] Example D12

[0115] The procedure was carried out in accordance with Example D1, except that steps (2), (3), and (4) were not performed, i.e., no ZSM-5 molecular sieve and MoO3 nanoparticle modification was performed.

[0116] Test case

[0117] (I) The materials obtained after alloying treatment in step (1) of each embodiment and comparative example (i.e., composite palladium-based alloy materials) were characterized. The characterization method is as follows, and the crystal structure parameters of the composite palladium-based alloy materials are shown in Table 2.

[0118] The crystal structure analysis of the composite palladium-based alloy was performed on an X'Pert PRO / PANalytical automated X-ray diffractometer manufactured by Philips, Netherlands. The experimental conditions were Cu K α X-rays (λ = 0.1543 nm), tube voltage 40 kV, current 40 mA, diffraction angle 2θ scan range 10-90°. The interplanar spacing of the sample was calculated using the Bragg equation.

[0119] d=λ / 2sinθ

[0120] Where λ corresponds to Cu K α The wavelength of the radiation, θ is the angle of the diffraction peak.

[0121] The crystal structure of the composite palladium-based alloy was tested at the European Synchrotron Radiation Facility (beam BM25A) in France, which has higher resolution, with synchrotron radiation λ = 0.0618886 nm or 0.077449 ​​nm and tube voltage of 10.0335 keV or 20.0335 keV. Initially, a 10 × 1 mm sample was used. 2 The sample was placed in a 2mm diameter quartz capillary tube, with both ends sealed with quartz wool. The capillary tube was then mounted on a rotating sample stage (to ensure uniform temperature and a larger X-ray irradiation area). The test temperature range was 298-473K (heated by a hot air blower), and the pressure range was 10... -4 The test atmosphere was -130 kPa. Hydrogen gas was first introduced and treated for 30 minutes, then a vacuum was drawn, and helium gas was introduced as a protective gas for measurement.

[0122] Methods for testing the lattice parameters of composite palladium-based alloy materials: Combining the above-mentioned in-situ XRD tests, the cell parameters of the palladium-based alloy materials are obtained (represented by three cell constants a, b, and c, and the three inter-edge angles α, β, and γ). According to the formula d1 = a / (α... 2 +β 2 +γ 2 ) 0.5 d2=b / (α) 2 +β 2 +γ 2 ) 0.5 d3=c / (α) 2 +β 2 +γ 2 ) 0.5 The interplanar spacing (d1 d2 d3) of the corresponding characteristic crystal planes is calculated. That is, the PdCuAu alloy material obtained in this invention belongs to the face-centered cubic close-packed (FCC) structure. Its characteristic crystal planes include (110), (111), (220), (311), and (222). At the same time, according to the X-ray diffraction results, a series of different characteristic crystal plane ratios (the intensity corresponding to different crystal planes) can be obtained. For example, in the PdCuAu alloy material obtained in this invention, the (110) plane corresponds to the characteristic peak at 2θ = 40° ± 1°, the (111) plane corresponds to the characteristic peak at 2θ = 46° ± 1°, the (220) plane corresponds to the characteristic peak at 2θ = 69° ± 1°, the (311) plane corresponds to the characteristic peak at 2θ = 83° ± 1°, and the (222) plane corresponds to the characteristic peak at 2θ = 87° ± 1°. Using HighScorePlus analysis software, combined with the peak intensities of the aforementioned characteristic crystal planes, the lattice parameters k of the corresponding materials are calculated.

[0123] The thickness of the composite palladium-based alloy material was tested by scanning electron microscopy (model: JSM-7610F). The thickness of the alloy film was determined by measuring the corresponding scale according to the magnification. The surface smoothness of the obtained composite palladium-based alloy material could also be observed by scanning electron microscopy. The results showed that the surface of the palladium-based alloy material prepared by this invention was smooth and free of defects.

[0124] The method for testing the half-peak width (WHM) of composite palladium-based alloy materials is as follows: based on the XRD spectrum test results, combined with HighScore Plus software analysis, the radian value of the WHM is obtained.

[0125] (II) The composite films (materials obtained before oxide deposition) obtained from each embodiment and comparative example were subjected to solid-phase exfoliation treatment to peel off the molecular sieves for characterization. The characterization method is as follows, and the relevant structural parameters of the molecular sieves attached to the surface of the composite palladium-based alloy material are obtained, as shown in Table 2.

[0126] The molecular sieve samples were analyzed using an Empyrean X-ray diffractometer from Malvern-Panalytical. The test conditions were: Cu target, Ka radiation, Ni filter, tube voltage 40 kV, tube current 40 mA, scintillation counter, step size 0.0131°, scan range 5–35°, and scan rate 2.5° / min. The results showed that it was a ZSM-5 aluminosilicate molecular sieve with a double ten-membered ring cross-channel structure (MFI structure). (The four characteristic peaks in the XRD patterns of each embodiment between 23° and 25° indicate that the material contains a double ten-membered ring cross-channel structure, consistent with the characteristics of ZSM-5 aluminosilicate molecular sieves, indicating that the obtained molecular sieves were all ZSM-5 aluminosilicate molecular sieves).

[0127] Methods for determining the specific surface area and average pore size of molecular sieves: The tests were conducted using a Micromeritics ASAP 2020 physical adsorption analyzer (USA). Samples were subjected to high vacuum treatment at 363 K and 573 K for 1 h and 3 h, respectively, followed by adsorption using N2 as the adsorbate at a constant temperature of 77 K. The BET specific surface area was obtained from the N2 adsorption isotherm combined with the BET equation; the average pore size was determined using the BJH method, calculated from the desorption branch of the N2 adsorption isotherm.

[0128] Method for testing the crystallinity of molecular sieves: A conventional X-ray diffractometer was used with a tube voltage of 40 kV, a tube current of 40 mA, and a scanning speed of 2.5° / min. The diffraction patterns of the samples were recorded within the range of 2θ = 5–35°. ZSM-5 sample M196697 from Shanghai Aladdin Biochemical Technology Co., Ltd. was used as a reference sample, with its relative crystallinity set to 100. The relative crystallinity of each sample was calculated by summing the peak intensities of its characteristic diffraction peaks at 2θ = 7.96°, 8.83°, 23.18°, 23.99°, and 24.45° and comparing this sum with the sum of the peak intensities of the reference sample.

[0129] The methods for testing the average particle size of molecular sieves are as follows: observe the microstructure of the molecular sieve in the sample using a transmission electron microscope and measure the diameter according to the scale bar; calculate the corresponding particle size distribution by taking the average of several samples using mathematical statistical methods.

[0130] The thickness of the molecular sieve is determined by scanning electron microscopy, and the thickness of the molecular sieve membrane is determined by measuring the corresponding scale according to the magnification.

[0131] The method for determining the infrared hydroxyl content of molecular sieves is as follows: Using KBr as a background, the Fourier transform infrared spectrum of the sample is recorded on a Bruker-INVENIO R and Tensor 27 infrared spectrometer. The sample is placed in a flow cell and vacuumed at 823 K for 2 hours, with the wavelength ranging from 4000 to 650 cm⁻¹. -1The hydroxyl content within a certain range was determined by summing 32 scans at a specific wavenumber. The corresponding spectrum was obtained at a wavenumber of 3500 cm⁻¹. -1 The nearby peaks represent the relative content of hydroxyl groups in the molecular sieve, wavenumber 3750 cm⁻¹. -1 The peaks near the molecular sieve represent the relative content of hydroxyl groups at the molecular sieve tip. The change in peak area indicates the degree of reduction in the total amount of hydroxyl groups before and after hydrophobic treatment. A larger peak area at the corresponding position indicates a higher hydroxyl content, which can qualitatively describe the hydrophobic properties of the membrane material (the infrared characterization results of hydroxyl groups before and after silanization reagent treatment show that the wavenumber after hydrophobic treatment is 3500 cm⁻¹). -1 Wavenumber 3750cm -1 The significantly reduced peak area indicates that the hydrophobic treatment method described in this invention can effectively reduce the number of hydroxyl groups on the membrane material surface and improve the hydrophobicity of the membrane material.

[0132] The silicon NMR test method for molecular sieves was as follows: On a VARIAN VNMRS 400WB NMR spectrometer, a single-pulse method was used with (CH3)3Si(CH2)3SO3Na as the chemical shift reference, and a rotation rate of 3 kHz and a cycle delay of 60 s were applied at a frequency of 79.43 MHz. 29 Si MAS NMR spectroscopy measurements. The peak areas near -113 ppm and -103 ppm in the corresponding spectra represent the relative contents of the silicon framework structures Q4:Si(OSi)4 and Q3:Si(OSi)3OH in the molecular sieve, respectively. The ratio Q4 / Q3 represents the relative content of silanol groups on the molecular sieve. A higher Q4 / Q3 value indicates fewer silanol groups and better hydrophobicity of the material; see Table 2 for the corresponding values ​​of "Silanol Groups (Q4 / Q3)". The degree of reduction in the relative content of silanol groups can be determined based on the change in the ratio before and after hydrophobicity treatment (NMR characterization results before and after silanization reagent treatment show that Q4 / Q3 decreases after hydrophobicity treatment, indicating that the hydrophobic treatment method described in this invention can effectively reduce the number of silanol groups on the membrane material surface and improve the hydrophobicity of the membrane material). The silicon NMR characterization results of the composite membrane prepared in Example D1 are shown below. Figure 2 As shown, dashed line 1 represents the peak area of ​​the composite membrane material before silanization treatment near chemical shifts of -113 ppm and -103 ppm, corresponding to the relative content of the molecular sieve silicon framework structures Q4:Si(OSi)4 and Q3:Si(OSi)3OH, with a ratio (Q4 / Q3) of 4.321; solid line 2 represents the peak area of ​​the composite membrane material after silanization treatment near chemical shifts of -113 ppm and -103 ppm, corresponding to the relative content of the molecular sieve silicon framework structures Q4:Si(OSi)4 and Q3:Si(OSi)3OH, with a ratio (Q4 / Q3) of 8.591.

[0133] (IV) Overall testing of composite membranes

[0134] The obtained composite membrane was tested for liquid contact angle. Specifically, the contact state between different liquids and the composite membrane was captured by the built-in high-speed camera of the Data Physics ContactAngle System OCA 25 instrument using different liquids as the medium, and the contact angle information was obtained after processing by the built-in software.

[0135] E act (Hydrogen permeation activation energy, unit: kJ·mol) -1 The test method involves measuring the hydrogen permeation rate from 573 K to 773 K under a transmembrane pressure difference of 0.1 MPa, combined with the Arrhenius equation J. H2 =J H2 °exp(-E act / RT), calculated through measurement, where J H2 It is the hydrogen permeation diffusion rate, J H2 ° is the hydrogen permeation diffusion coefficient, R is the gas constant, and T is the absolute temperature. The higher the hydrogen permeation activation energy, the higher the hydrogen mass transfer resistance of the composite membrane material, and the more difficult it is for hydrogen to permeate and diffuse through the composite membrane.

[0136] J H2 (Hydrogen permeation rate, unit: mol·m) -2 ·s -1 The test method involves measuring the volume of hydrogen passing through the palladium-based composite membrane per minute (in liters) at 20℃ and a transmembrane pressure difference of 0.1 MPa, and then normalizing it to the hydrogen permeation rate (mol·m²) based on the membrane area (square meters). -2 ·s -1 ).

[0137] J N2 (Nitrogen permeation diffusion rate, unit: mmol·m) -2 ·s -1 The test method involves measuring the volume (mL) of nitrogen gas passing through the palladium-based composite membrane per minute at 20℃ and a transmembrane pressure difference of 0.1 MPa, and then normalizing it to the hydrogen permeation rate (mmol·m²) based on the membrane area (m²). -2 ·s -1 ).

[0138] The elemental composition of the composite film was analyzed by X-ray fluorescence (XRF) combined with inductively coupled plasma optical emission spectroscopy (ICP-OES), and the valence states of the elements were determined by X-ray photoelectron spectroscopy (XPS).

[0139] The morphology of the oxide nanoparticles was observed using scanning electron microscopy (SEM), and the average particle size was calculated. The SEM image of the composite film prepared in Example D1 is shown below. Figure 1 As shown, (a) is the overall morphology of the composite membrane material after modification with ZSM-5 molecular sieve loaded with MoO3, and (b) is the morphology of MoO3 nanoparticles loaded on ZSM-5 molecular sieve after local magnification.

[0140] Table 2

[0141]

[0142] Table 2 (continued)

[0143]

[0144] (IV) Application Testing

[0145] The performance of the composite membrane prepared in the above embodiments in the preparation of high-purity hydrogen was tested.

[0146] The composite membrane prepared above was encapsulated in a tubular reactor. Nitrogen gas was first introduced into the inner and outer sides of the composite membrane at flow rates of 10 mL / min and 30 mL / min, respectively. The temperature was increased to 723 K at a rate of 1 K / min to activate the composite membrane for 4 hours. Then, the gas to be separated (sulfur-containing hydrogen gas containing 280 ppm H2S, including 90 vol% H2, 6 vol% N2, 3 vol% CH4, and 0.9 vol% CO2) was introduced into the tubular reactor through the gas inlet. Under the separation action of the composite membrane, high-purity hydrogen gas was discharged from the permeate side outlet, and the remaining components were discharged from the effluent side outlet. The separation temperature was controlled at 200℃, and the pressure difference (P) between the inside and outside of the composite membrane was maintained. 外侧 -P 内侧 The pressure is equal to 0.5 MPa. The gas components to be separated, high-purity hydrogen, and residual components during the separation process were analyzed online using a Shanghai Tianmei SCION-456 gas chromatograph equipped with FID and PDHID detectors. Product distribution and hydrogen purity changes were monitored in real time. High-purity hydrogen was tested every 5 hours. The continuous operating time was recorded when the purity of high-purity hydrogen decreased to 99.9%. The initial separation values ​​and experimental measurements after reaching the continuous operating time are shown in Table 3. The hydrogen sulfide content on the permeate side is represented by C. H2S The purity of the high-purity hydrogen obtained from the permeation side is indicated by S. 高 The hydrogen recovery rate is expressed in H2. 回 , where H 回 The calculation formula is:

[0147] H 回 = Amount of hydrogen on the permeate side / (Amount of hydrogen on the permeate side + Amount of hydrogen on the residual permeate side).

[0148] The sulfur content in both the composite membrane and the composite palladium-based alloy material was measured using inductively coupled plasma atomic emission spectrometry (ICP).

[0149] Table 3

[0150]

[0151] In addition, the molecular sieves on the composite membrane before and after hydrogen separation were removed, and then the scanning electron microscope images of the composite palladium-based alloy material before and after hydrogen separation were compared to see if cracks were generated. Figure 3 (a) is a scanning electron microscope image of the composite palladium-based alloy material in the composite membrane before hydrogen separation in Example D1. Figure 3 (b) is a scanning electron microscope image of the composite palladium-based alloy material in the composite membrane after hydrogen separation in Example D1. Figure 3 (a) and Figure 3 (b) In comparison, after the composite membrane of Example D1 was continuously operated for a certain period of time, no cracking of the composite palladium-based alloy material occurred.

[0152] Figure 4 These are scanning electron microscope (SEM) images of the composite palladium-based alloy material of Example D12 before (a) and after (b) hydrogen separation and purification tests in a hydrogen sulfide atmosphere. Figure 4 (a) and Figure 4 (b) In comparison, the composite palladium-based alloy material of Example D12 experienced severe surface cracking after continuous operation for a certain period of time.

[0153] The molecular sieves on the composite membrane before and after hydrogen separation were removed, and then the presence of Pd4S characteristic peaks in the composite palladium-based alloy material before and after hydrogen separation was compared. Figure 5 (a) shows the X-ray diffraction patterns of the composite palladium-based alloy material of the composite membrane in Example D1 before (1) and after (2) hydrogen separation and purification tests in a hydrogen sulfide atmosphere. Figure 5 (b) shows the X-ray diffraction patterns of the composite palladium-based alloy material of Example D12 before (1) and after (2) hydrogen separation and purification tests in a hydrogen sulfide atmosphere. Figure 5 (a) It can be seen that after the composite film of Example D1 has been running continuously for a certain period of time, the composite palladium-based alloy material still maintains the characteristic peaks of face-centered cubic close packing and does not generate the characteristic peaks of Pd4S. Figure 5 (b) It can be seen that after the composite palladium-based alloy material of Example D12 has been running continuously for a certain period of time, in addition to the characteristic peaks of face-centered cubic close packing, Pd4S characteristic peaks are also generated in the composite palladium-based alloy material.

[0154] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A gold-containing composite film with sulfur-resistant properties, characterized in that, The composite membrane comprises a composite palladium-based alloy material and a silica-alumina molecular sieve and a group VIB metal oxide sequentially attached to the surface of the composite palladium-based alloy material with hydrophobic groups. The composite palladium-based alloy material is composed of Pd, Cu, and Au, with a molar ratio of Pd, Cu, and Au of 100:(58-95):(9-37). The crystal structure of the composite palladium-based alloy material is face-centered cubic close-packed, with a lattice parameter k of 0.4098-4286 nm. In the XRD pattern of the composite palladium-based alloy material, 2θ = 40... o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.0524, and 2θ = 46. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.0873, and 2θ = 69. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.1222, and 2θ = 83. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.1396, and 2θ = 87. o ±1 o The full width at half maximum (FWHM) of the characteristic peak at that location is less than or equal to 0.1571. The crystal phase structure of the composite palladium-based alloy material was determined using an X-ray diffractometer. The experimental conditions were Cu... K α ray, λ =0.1543 nm, tube voltage 40 kV, current 40 mA, diffraction angle 2 θ The scanning range is 10-90. o ; The method for testing the half-peak width (WHM) of composite palladium-based alloy materials is as follows: based on the X-ray diffraction test results, combined with HighScore Plus software analysis, the radian value of the WHM is obtained.

2. The composite membrane according to claim 1, wherein, The thickness of the composite palladium-based alloy material is 0.5-30µm.

3. The composite membrane according to claim 1, wherein, The thickness of the composite palladium-based alloy material is 5-15µm.

4. The composite membrane according to claim 1 or 2, wherein, The water contact angle of the composite membrane is greater than or equal to 90°. o ; And / or, the composite membrane is a tubular membrane; And / or, the composite membrane further includes a support, on which the composite palladium-based alloy material is attached, and the thickness of the support is 0.1-20 mm.

5. The composite membrane according to claim 1 or 2, wherein, The water contact angle of the composite membrane is greater than or equal to 105°. o .

6. The composite membrane according to claim 1 or 2, wherein, The composite membrane also includes a support body, on which the composite palladium-based alloy material is attached, and the thickness of the support body is 2-5 mm.

7. The composite membrane according to claim 1 or 2, wherein, The hydrophobic group-modified silica-alumina molecular sieve 29 In the Si MAS NMR spectrum, the ratio of the peak areas of the peaks with chemical shifts near -113 ppm and -103 ppm is 6-12. And / or, the hydrophobic groups in the hydrophobic group-modified silica-alumina molecular sieve are provided by at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, 3-aminopropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, 1-[3-(trimethoxysilyl)propyl]urea, (3-chloropropyl)trimethoxysilane, and 3-chloropropyltriethoxysilane; And / or, the hydrophobic group-modified silica-alumina molecular sieve is at least one of the following: hydrophobic group-modified ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-34, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, SAPO-31, SAPO-34, SAPO-44, RUB-13, MCM-68, Y-type molecular sieve and mordenite; And / or, the thickness of the hydrophobic group-modified silica-alumina molecular sieve is 2-125µm; And / or, the silica-alumina molecular sieves modified with hydrophobic groups have a silica-alumina molar ratio of (5-100):1; an average particle size of 100-350 nm; an average pore size of 0.35-280 nm; and a specific surface area of ​​75-800 m². 2 / g; crystallinity greater than or equal to 90%.

8. The composite membrane according to claim 1 or 2, wherein, The hydrophobic groups in the modified silica-alumina molecular sieve are provided by at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, and 3-aminopropyltrimethoxysilane.

9. The composite membrane according to claim 1 or 2, wherein, The thickness of the hydrophobic group-modified silica-alumina molecular sieve is 15-50µm.

10. The composite membrane according to claim 1 or 2, wherein, The molar ratio of silicon to aluminum in the hydrophobic group-modified silica-alumina molecular sieve is (10-40):

1.

11. The composite membrane according to claim 1 or 2, wherein, The average particle size of the hydrophobic group-modified silica-alumina molecular sieve is 150-200 nm.

12. The composite membrane according to claim 1 or 2, wherein, The average pore size of the hydrophobic group-modified silica-alumina molecular sieve is 0.85-55 nm.

13. The composite membrane according to claim 1 or 2, wherein, The specific surface area of ​​hydrophobic group-modified silica-alumina molecular sieves is 100-550 m². 2 / g.

14. The composite membrane according to claim 1 or 2, wherein, The crystallinity of the hydrophobic group-modified silica-alumina molecular sieve is 95-99%.

15. The composite membrane according to claim 1 or 2, wherein, The average particle size of the oxides of the group VIB metals is 10-750 nm.

16. The composite membrane according to claim 1 or 2, wherein, The content of the oxides of the group VIB metals is such that the molar ratio between the group VIB metals and Pd is 0.01-0.

5.

17. A method for preparing a gold-containing composite film with sulfur resistance, characterized in that, The method includes: (1) Pd, Cu and Au are deposited on the support, and then the support with Pd, Cu and Au deposited is alloyed, wherein the molar ratio of Pd, Cu and Au is 100:(58-95):(9-37). The alloying process is as follows: in an activating atmosphere, heat treatment is first performed at a temperature of 380-580℃ and a pressure greater than 0.2MPa, and then the temperature is reduced to below 230℃ at a rate greater than 35℃ / min. The gas providing the activating atmosphere may optionally include an alkaline gas. (2) The alloyed material is placed in a solution of a precursor containing silicon-aluminum molecular sieve and subjected to hydrothermal crystallization, drying and calcination in sequence to obtain a composite membrane precursor; (3) Modify the composite membrane precursor with hydrophobic groups; (4) Deposit oxides of group VIB metals on the surface of the product modified with hydrophobic groups obtained in step (3).

18. The method according to claim 17, wherein, The alloying treatment is performed by treating the material in an activating atmosphere at a temperature of 400-500℃ and a pressure of 0.24-0.35MPa for 4-6 hours. The temperature is reduced to 180-230℃ at a rate of 40-65℃ / min; And / or, the content of alkaline gas in the gas providing the activating atmosphere is greater than or equal to 20% by volume; And / or, the alkaline gas is selected from at least one of ethylenediamine, NH3, PH3 and N2H4; And / or, the total thickness of Pd, Cu and Au deposited on the support is 0.5-30µm; And / or, the thickness of the support is 0.1-20 mm.

19. The method of claim 17, wherein, The total thickness of Pd, Cu and Au deposited on the support is 5-15µm.

20. The method of claim 17, wherein, The thickness of the support is 2-5mm.

21. The method according to claim 17, wherein, The precursor solution of the silicon-aluminum molecular sieve contains a silicon source, an aluminum source, a template agent, and water.

22. The method according to claim 21, wherein, The molar ratio of the silicon source, aluminum source, template agent, and water is 100:(1-20):(8-60):(75-2500). And / or, the content of template agent in the solution of the precursor containing silica-alumina molecular sieve is 0.25-1.2 mol / L; And / or, relative to 1g of alloyed material, the amount of the precursor solution containing silica-alumina molecular sieve is 0.05-2 mL; And / or, the silicon source is at least one of silicate ester, silicate and silicon dioxide; And / or, the aluminum source is at least one of aluminate, alumina, aluminum salt, aluminum sol, and organic aluminum alkoxide; And / or, the template agent is at least one of tetraalkylammonium hydroxide, alkylamine, and tetraalkylammonium halide.

23. The method according to claim 21, wherein, The molar ratio of the silicon source, aluminum source, template agent, and water is 100:(2.5-10):(30-60):(80-1200).

24. The method according to claim 21, wherein, The silicon source is selected from at least one of tetrabutyl orthosilicate, tetraethyl orthosilicate, sodium silicate, potassium silicate, silica sol, and water glass.

25. The method according to claim 21, wherein, The aluminum source is selected from at least one of sodium aluminate, boehmite, aluminum sulfate, aluminum nitrate, and aluminum isopropoxide.

26. The method according to claim 21, wherein, The template agent is selected from at least one of tetrabutylammonium hydroxide, tetrapropylammonium hydroxide, tetraethylammonium hydroxide, triethylamine, hexadecyltrimethylammonium bromide, and isopropylamine.

27. The method according to claim 17, wherein, The hydrothermal crystallization method involves aging followed by crystallization. The aging conditions include an aging temperature of 80-100℃ and an aging time of 3.5-6.5h. The crystallization conditions include a crystallization temperature of 150-180℃ and a crystallization time of 48-96h. And / or, the drying conditions include: drying temperature 35-60℃, drying time 16-24h; And / or, the calcination conditions include: calcination temperature of 550-600℃ and calcination time of 6-8h.

28. The method according to claim 17, wherein, The method of modifying the composite membrane precursor with hydrophobic groups is as follows: the composite membrane precursor is silanized using a silanizing agent.

29. The method according to claim 28, wherein, The amount of the silanizing agent used is 3-9 mL relative to 1 g of the composite membrane precursor.

30. The method according to claim 28, wherein, The silanizing agent is selected from at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane, 3-aminopropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, 3-aminopropyltriethoxysilane, N,N-diethyl-3-(trimethoxysilyl)propylamine, 1-[3-(trimethoxysilyl)propyl]urea, (3-chloropropyl)trimethoxysilane, and 3-chloropropyltriethoxysilane.

31. The method according to claim 28, wherein, The silanizing agent is selected from at least one of polymethylhydrosiloxane, vinyltriethoxysilane, 3-aminopropyltriethylsilane, N,N-diethyltrimethylsilane and 3-aminopropyltrimethoxysilane.

32. The method according to claim 17, wherein, The average particle size of the oxides of the group VIB metals is 10-750 nm.

33. The method according to claim 17, wherein, The amount of oxides of the group VIB metals deposited is such that the molar ratio between the group VIB metals and Pd is 0.01-0.

5.

34. The composite membrane prepared by the method according to any one of claims 17-33.

35. A composite palladium-based alloy material, characterized in that, The composite palladium-based alloy material is the composite palladium-based alloy material as defined in any one of claims 1-16 or the product of the alloying treatment described in any one of claims 17-34.

36. The application of the composite membrane according to any one of claims 1-16 or 34 in hydrogen separation.

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