A copper-based oxygen permeable membrane material, and a preparation method and application thereof

Abstract

The application provides a copper-based oxygen permeable membrane material and a preparation method and application thereof. The chemical general formula of the copper-based oxygen permeable membrane material is La2Cu 1‑b M b O 4+δ X c , wherein X is selected from any one of F, Cl, Br and I; δ is a non-stoichiometric ratio, δ<=0.15, 0 The copper-based oxygen permeable membrane material has excellent oxygen permeable quantity and stability.

Description

Technical Field

[0001] This invention belongs to the field of hybrid conductor membrane materials, specifically relating to a novel copper-based oxygen-permeable membrane material, its preparation method, and its application. Background Technology

[0002] With the continuous development of hybrid conductor oxygen-permeable membrane materials, they have received increasing attention as an environmentally friendly, clean, and efficient air separation membrane. Due to their excellent oxygen selective permeability, hybrid conductor oxygen-permeable membrane materials have been widely used in gas separation, partial oxidation of methane (POM), and partial coupling of methane. In addition, hybrid conductor oxygen-permeable membrane materials are expected to be used in the oxygen-enriched combustion process of power plants to achieve carbon dioxide capture and storage, and are considered a potential clean energy material that can improve environmental and climate issues.

[0003] However, to date, there are not many oxygen-permeable membrane materials that can be truly applied industrially. The main reason hindering the industrialization of hybrid conductor oxygen-permeable membrane materials lies in the oxygen permeability and stability of the membrane material in a high-temperature CO2 atmosphere. To address this issue of oxygen permeability and stability, existing technologies disclose some solutions for different types of oxygen-permeable membrane materials, such as:

[0004] Chinese patent document CN201610025622.9 discloses the application of a fluorine-doped perovskite membrane in oxygen separation, and specifically discloses a fluorine-doped perovskite membrane, the membrane material of which is of the general formula A. x A' 1-x B y B' 1-y O 3-δ F γ This study investigates perovskite-type oxygen-permeable membranes, where δ represents the oxygen lattice defect number, A and A' are any one of Ce, Pr, Nd, Ca, Sr, Ba, and La; B and B' are any one of Co, Fe, Nb, Ta, Mo, W, Sc, Ti, Zr, Sn, and Sb; 0 ≤ x ≤ 1, 0 ≤ y ≤ 1; 0 < γ ≤ 1. The material is prepared using a solid-state reaction method, and the film formation process employs uniaxial pressing, plastic extrusion, or phase transformation. This scheme studies perovskite-type oxygen-permeable membranes that rely on oxygen holes for oxygen ion conduction. By doping with F (the element with the highest electronegativity), the charge density of lattice oxygen can be reduced, thus facilitating the generation of oxygen holes. To improve its oxygen permeability. However, this type of material contains alkaline earth metals, which easily form carbonate impurity phases in a high-temperature CO2 atmosphere, thereby blocking the oxygen transport channels and greatly reducing the oxygen permeability, mechanical strength and stability of the membrane material.

[0005] Chinese patent document CN202011585096.4 discloses a non-metallic anion-doped LAMOX-type oxygen ion conductor oxygen-permeable membrane material, its preparation method, and its application. The general chemical formula of the membrane material is: La₂Mo. 2-b M b O 9-δ X c M represents one or two of the metal cations V, Nb, Ta, Cr, W, Fe, Al, and Mn; X represents one of the halide anions F, Cl, Br, and I; δ is a non-stoichiometric ratio, 0 ≤ δ ≤ 1; 0.1 ≤ b ≤ 1.4, 0 ≤ c ≤ 1. This literature studies a LAMOX-type oxygen-permeable membrane, which also relies on oxygen holes for oxygen ion conduction. By doping with F (the element with the highest electronegativity), the charge density of lattice oxygen can be reduced, thus making it easier to generate oxygen holes and improving its oxygen permeability. However, in materials where interstitial oxygen conduction is dominant, F doping will reduce the charge density of interstitial oxygen, O2(g) + 4e′ → 2O″. i This is not conducive to the generation of interstitial oxygen, resulting in a significant decrease in the interstitial oxygen conduction capacity.

[0006] Chinese patent document CN201210259069.7 discloses a carbon dioxide-resistant hybrid conductor oxygen-permeable membrane, its preparation method, and its application. The chemical formula of the oxygen-permeable membrane is A2BO. 4+δ Where δ represents oxygen non-stoichiometry, A is one or more of La, Ce, Pr, Nd, Pm, and Sm, and B is one or more of Mn, Ni, Cu, Zn, Ga, Al, Fe, Mg, and In. The preparation method is as follows: Nitrate or acetate solutions of various metal elements are dissolved in a multifunctional organic acid; the resulting pre-powder is heated and decomposed, then calcined and ground to obtain powder; the powder is pressed into shape and sintered to obtain a mixed conductor oxygen-permeable membrane. This scheme improves the CO2 resistance of the mixed conductor oxygen-permeable membrane by using rare earth metal elements instead of alkaline earth metals as the A-site of the mixed conductor; however, it does not solve the technical problem of low oxygen permeability.

[0007] Chinese patent document CN201710208941.8 discloses an anion-doped K2NiF4 type hybrid conductor oxygen-permeable membrane material, its preparation method, and its application. The chemical formula of this material is: A a Ni 1-b B b O 4+δ-c / 2 X cWhere A is one or two of La, Pr, Nd, Sm, Gd, and Er; B is one or two of Fe, Co, Cu, Zn, Al, and Ga; X is one of F, Cl, Br, and I; δ is a non-stoichiometric ratio, 1.8≤a≤2, 0≤b≤0.3, and 0≤c≤0.5. This material is prepared using an EDTA-citric acid mixed complexation method. The scheme studied is based on Ni-based K2NiF4 type materials. These Ni-based materials have a large amount of interstitial oxygen (large non-stoichiometric ratio) and are primarily materials that rely on interstitial oxygen conduction. Although this material has high oxygen permeability and good catalytic performance for hydrocarbon conversion, it is extremely prone to carbon deposition, leading to poor stability and making it unsuitable for constructing membrane reactors for hydrocarbon conversion. Furthermore, when improving this Ni-based material, the copper doping cannot exceed 0.3%, which cannot fundamentally improve the problems of Ni-based materials.

[0008] In addition, none of the methods for improving the oxygen permeability of oxygen-permeable membranes disclosed in the above literature are applicable to copper-based oxygen-permeable membrane materials. Therefore, although copper-based oxygen-permeable membrane materials are also used in catalytic reactions, their application is severely limited due to their low oxygen permeability. Improving the oxygen permeability of copper-based oxygen-permeable membrane materials is of great significance for expanding their application. Summary of the Invention

[0009] To address the problem of low oxygen permeability in existing copper-based oxygen-permeable membrane materials, this invention provides a novel copper-based oxygen-permeable membrane material with high oxygen permeability.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A copper-based oxygen-permeable membrane material, wherein the general chemical formula of the copper-based oxygen-permeable membrane material is La₂Cu. 1-b M b O 4+δ X c Where X is selected from Cl, Br and I; δ is a non-stoichiometric ratio (representing the amount of interstitial oxygen in the material), δ≤0.15, 0<c<0.2, 0≤b≤0.2, and M is selected from Ni or W.

[0012] Preferably, the copper-based oxygen-permeable membrane material has the chemical formula La₂Cu. 1-b M b O 4+δ X c In the given condition, 0 < c ≤ 0.15, b = 0, X is Cl, and δ ≤ 0.05.

[0013] Through in-depth research, the inventors discovered that existing methods for improving oxygen permeability are not applicable to copper-based oxygen-permeable membrane materials because: Cu-based materials have a smaller non-stoichiometry (compared to Ni-based materials), and they are materials that conduct oxygen ions and interstitial oxygen in a mixed manner (the amounts of interstitial oxygen and hole oxygen are roughly the same, and both contribute to the conduction of oxygen ions).

[0014]

[0015] However, oxygen vacancies and interstitial oxygen can neutralize each other and cannot coexist in large quantities at the same time.

[0016]

[0017] These materials have a low non-stoichiometry (unlike Ni-based materials) and are materials that conduct oxygen vacancies and interstitial oxygen in a mixed manner (δ ~ 0, the amounts of interstitial oxygen and vacancy oxygen are roughly the same, and both contribute to oxygen ion conduction). These materials also have applications in catalytic reactions, but their oxygen permeability is low, and current research is limited. Most existing technologies use metal ion doping to optimize their separation performance, but the improvement in permeability is not significant. Anion doping, discovered in recent years, is also an effective optimization strategy, but it is limited to Ni-based materials, and there are no reports on anion doping for Cu-based materials. Therefore, the inventors attempted to use anion doping to regulate and improve the separation performance of Cu-based materials, but the results were not ideal. Further in-depth research revealed that the content of halogens and copper in copper-based materials obtained through anion doping directly affects the performance of the copper-based materials: if c is too high, impurities will be generated, resulting in impurities in the material; if b is too high, more interstitial oxygen will be introduced, which is not conducive to improving separation performance using anion doping. Therefore, by using appropriate amounts of halide anion doping combined with a specific general formula, this invention can significantly reduce the valence electron density of O, weaken the Coulomb force between metal ions and oxygen ions, and improve oxygen mobility, thereby enhancing the oxygen permeability of the material.

[0018] The preparation method of the copper-based oxygen-permeable membrane material provided by the present invention is not particularly limited. It can be prepared using a common anion-doped oxygen-permeable membrane material, such as by gel method or solid-phase method.

[0019] Specifically, the copper-based oxygen-permeable membrane material provided by the present invention can be prepared by the following method, including the following steps:

[0020] 1) Mix the La source, Cu source, M source and X source, and dry to obtain precursor powder;

[0021] 2) The precursor powder is calcined to obtain the powder of the membrane material;

[0022] 3) Press the powder of the membrane material into shape and sinter it to obtain the copper-based oxygen-permeable membrane material.

[0023] Optionally, the above preparation method can be selected from the solid-state method. The present invention does not particularly limit the conditions in each step, and the common conditions of the solid-state method can be used. For example, in step 1), the mixing method is ball milling, and an organic solvent is added during the ball milling process. The organic solvent can be selected from acetone or ethanol, preferably acetone.

[0024] Optionally, the ball mill rotates at a speed of 300-550 rpm for 3-24 hours.

[0025] Optionally, in step 2), the calcination temperature is 700-900℃, the time is 5-20h, and the heating rate is 1-5℃ / min.

[0026] Optionally, in step 3), the sintering temperature is 950-1200℃, the time is 5-20h, and the heating rate is 1-5℃ / min.

[0027] When using a solid-state method for preparation, this invention does not particularly limit the types of substances in step 1); commonly used substances are acceptable. For example, the La source can be an inorganic salt or oxide of La, such as lanthanum oxide, lanthanum nitrate, lanthanum oxalate, lanthanum halide, and lanthanum sulfate; the copper source can be an inorganic salt or oxide of copper, such as copper oxide, copper nitrate, copper oxalate, copper chloride, and copper sulfate; the X source can be a lanthanum halide or copper halide, such as lanthanum chloride, lanthanum bromide, lanthanum fluoride, copper chloride, and copper bromide; and the M source can be an oxide or inorganic salt of M, such as nitrates, oxalates, and sulfates.

[0028] Optionally, the above preparation method can also be selected from the gelation method, using conventional conditions for the gelation method, such as in step 1), where the mixing method is a mixed complexation of ethylenediaminetetraacetic acid and citric acid, including the following steps:

[0029] A) Mix aqueous solutions of La source, Cu source, M source and X source, add EDTA and citric acid, and then add an alkaline nonmetallic compound while stirring continuously to adjust the pH of the system to 6-8; to obtain a mixed solution;

[0030] B) The mixture is stirred and evaporated at 90–150°C to obtain a gel;

[0031] The La, Cu, M, and X sources mentioned above are all selected from water-soluble salts.

[0032] Optionally, in step 1), the drying process involves calcining the gel at 300-600°C for 2-5 hours.

[0033] Optionally, the total metal ions in the EDTA:citric acid:metal salt mixed solution are (1-2):(1-3):(1-2).

[0034] The compression molding method in step 3) is not particularly limited. It can be any conventional method in the industry, such as uniaxial compression, plastic extrusion or phase inversion molding.

[0035] The present invention also provides the application of the above-mentioned copper-based oxygen-permeable membrane material or the copper-based oxygen-permeable membrane material prepared by the above-mentioned method in the selective separation of oxygen, the construction of membrane reactors coupled with oxygen-related reactions, the reaction of methane oxidative coupling to produce ethylene, or the reaction of water cracking to produce hydrogen.

[0036] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0037] 1. This invention relates to Cu-based oxygen-permeable membrane materials. These materials have a relatively small non-stoichiometric ratio (compared to Ni-based oxygen-permeable membrane materials) and are materials that conduct oxygen vacancies and interstitial oxygen in a mixed manner. Although copper-based oxygen-permeable membrane materials are also used in catalytic reactions, their low oxygen permeability limits their research and application. Introducing anions into existing conventional copper-based oxygen-permeable membrane materials for doping still results in low oxygen permeability, failing to meet application requirements. Through in-depth research, the inventors discovered that excessive anion doping in copper-based oxygen-permeable membrane materials leads to impurities in the product, resulting in material impurity. Excessive content of other metal elements introduces more interstitial oxygen into the product, hindering the improvement of separation performance through anion doping. By introducing a specific amount of anions into a specific copper-based material, the oxygen permeability of the copper-based membrane material can be significantly increased, with a maximum increase of 1.7 times. The reason for this may be that the doping of halogen anions at the O site reduces the δ non-stoichiometry, leading to a decrease in interstitial oxygen. This indicates that the introduction of halogen ions can increase the content of vacant oxygen, thereby increasing its oxygen permeability. At the same time, the introduction of halogen ions can reduce the valence electron density of O, weaken the Coulomb force between metal ions and oxygen ions, and improve oxygen mobility, thus enhancing the oxygen permeability of the material and expanding the application fields of copper-based oxygen permeable membrane materials.

[0038] 2. The novel copper-based oxygen-permeable membrane material provided by this invention does not contain alkali metals or alkaline earth metals and has good stability under CO2 atmosphere. Attached Figure Description

[0039] Figure 1 The XRD patterns of the copper-based oxygen-permeable membrane materials prepared in Examples 1, 2, 1, and 2 of this invention are shown below.

[0040] Figure 2a , Figure 2b and Figure 2c SEM images of the copper-based oxygen-permeable membrane materials prepared in Comparative Example 2, Example 1, and Example 2 of the present invention are shown respectively.

[0041] Figure 3The results of in-situ XRD testing of the membrane material powder prepared in Example 2 of this invention in a CO2 atmosphere;

[0042] Figure 4 The XRD patterns of the copper-based oxygen-permeable membrane materials prepared in Comparative Examples 2, 3 and 4 of this invention are shown below.

[0043] Figure 5 The oxygen permeability curves of the copper-based oxygen-permeable membrane materials prepared in Examples 1, 2 and Comparative Example 2 of this invention are shown.

[0044] Figure 6 The oxygen permeability of the copper-based oxygen-permeable membrane material prepared in Example 2 of the present invention was subjected to different switching temperatures and different purge gas switching. Detailed Implementation

[0045] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0046] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0047] Example 1

[0048] This embodiment provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0049] 1) Weigh 12.925g La2O3, 3.182g CuO and 0.1635g LaCl3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0050] (2) After ball milling, the ball-milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 900°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0051] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0052] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1050°C until dense. The holding time is 5 hours, and the heating and cooling rates are both 5°C / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOCl. 0.05 .

[0053] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 1 As shown, the obtained X-ray diffraction pattern was compared with the standard PDF card, indicating that the copper-based oxygen-permeable membrane material is a pure-phase membrane. The oxygen non-stoichiometry ratio δ of the material was determined to be -0.07 by iodometric titration. The surface morphology of the membrane was characterized using a HITACHI SU8200 scanning electron microscope, and the results are as follows. Figure 2b As shown, by Figure 2b It can be seen that the grains are tightly packed together, without bubbles or pores, indicating that the prepared copper-based oxygen-permeable membrane material has good density.

[0054] Example 2

[0055] This embodiment provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0056] 1) Weigh 12.816g La2O3, 3.182g CuO and 0.327g LaCl3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0057] (2) After ball milling, the ball-milled suspension was placed in a fume hood for natural air drying. After complete drying, the obtained precursor powder was transferred to a muffle furnace for high-temperature sintering at 800℃ for 10 hours, with a heating and cooling rate of 2℃ / min, to obtain the membrane material powder. The membrane material powder was then characterized by in-situ X-ray diffraction in a CO2 atmosphere, and the results are as follows. Figure 3 As shown, the temperature change process is from 30℃ to 900℃, then from 900℃ to 30℃, and so on. Figure 3 It can be seen that the phase structure of the powder of this membrane material is stable in a CO2 atmosphere.

[0058] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0059] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1000℃ to achieve densification. The holding time is 10h, and the heating and cooling rates are both 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOCl. 0.1 .

[0060] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 1 As shown, the obtained X-ray diffraction pattern was compared with the standard PDF card, indicating that the copper-based oxygen-permeable membrane material is a pure-phase membrane. The oxygen non-stoichiometry ratio δ of the material was determined to be -0.12 by iodometric titration. The surface morphology of the membrane was characterized using a HITACHI SU8200 scanning electron microscope, and the results are as follows. Figure 2c As shown, by Figure 2c It can be seen that the grains are tightly packed together, without bubbles or pores, indicating that the prepared copper-based oxygen-permeable membrane material has good density.

[0061] Example 3

[0062] This embodiment provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0063] (1) Weigh 10.825g La(NO3)3·6H2O, 2.869g Cu(NO3)2·3H2O and 0.084g CuCl2, dissolve them in a large beaker containing deionized water, and mix thoroughly to obtain a metal salt mixed solution. Weigh 10.959g EDTA and 10.807g anhydrous citric acid according to the molar ratio of total metal ions: ethylenediaminetetraacetic acid (EDTA): anhydrous citric acid = 1:1:1.5, and add them to the above metal salt mixed solution.

[0064] (2) Under constant stirring, add 25% ammonia water dropwise to the metal salt mixture obtained in step (2) until the solution is clear and the pH value is approximately 8. Then, heat it in a constant temperature water bath at 90°C while stirring for about 12 hours to evaporate most of the water in the solution and form a gel. Transfer the gel to an evaporating dish and then heat it on a universal electric furnace at 300°C for about 2 hours until the powder becomes fluffy and there is no violent burning phenomenon. Then stop heating to obtain the precursor powder.

[0065] (3) After the precursor powder cools down, it is transferred to a crucible and then placed in a high-temperature muffle furnace and calcined at 700°C for 10 hours at a heating and cooling rate of 1°C / min to obtain the powder of the membrane material.

[0066] (4) Grind the powder of the membrane material obtained in step (3) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0067] (5) Transfer the membrane preform obtained in step (4) to a corundum plate, and then sinter it in a high-temperature muffle furnace at 950°C until it is dense. The holding time is 10 h, and the heating and cooling rates are both 2°C / min. After sintering, cool it to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOCl. 0.1 (The oxygen nonstoichiometry ratio δ of the material was determined to be -0.12 by iodometric titration).

[0068] Example 4

[0069] This embodiment provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0070] 1) Weigh 12.816g La2O3, 2.864g CuO, 0.300g NiO and 0.327g LaCl3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0071] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 850°C for 15 hours. The heating and cooling rates were 3°C / min to obtain the powder of the membrane material.

[0072] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0073] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then sintered in a high-temperature muffle furnace at 1100℃ for 10 hours, with a heating and cooling rate of 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material. The oxygen non-stoichiometry ratio δ of the material is determined to be 0.08 by iodometric titration. This membrane material is denoted as La2Cu. 0.9 Ni 0.1 O4Cl 0.1 .

[0074] Example 5

[0075] This embodiment provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0076] 1) Weigh 12.816g La2O3, 2.864g CuO, 0.927g WO3 and 0.327g LaCl3 and add them to a ball mill jar, then add 30mL of acetone and ball mill at 350r / min for 24h;

[0077] (2) After ball milling, the ball-milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 900°C for 20 hours. The heating and cooling rates were 4°C / min to obtain the powder of the membrane material.

[0078] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0079] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then sintered in a high-temperature muffle furnace at 1150°C for 5 hours, with a heating and cooling rate of 3°C / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material. The oxygen non-stoichiometry ratio δ of the material is determined to be 0.15 by iodometric titration. This membrane material is denoted as La2Cu. 0.9 W 0.1 O4Cl 0.1 .

[0080] Comparative Example 1

[0081] This comparative example provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0082] 1) Weigh 12.598g La2O3, 3.182g CuO and 0.654g LaCl3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0083] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 800°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0084] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0085] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1000℃ to achieve densification. The holding time is 10h, and the heating and cooling rates are both 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOCl. 0.2 .

[0086] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 1 As shown, the obtained X-ray diffraction pattern was compared with the standard PDF card, and impurity phases were found; therefore, oxygen permeability testing was not performed. The oxygen non-stoichiometry ratio δ of the material was determined to be 0 by iodometric titration.

[0087] Comparative Example 2

[0088] This comparative example provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0089] 1) Weigh 13.034g La2O3 and 3.182g CuO into a ball mill jar, then add 30mL of acetone and ball mill at 350r / min for 24h;

[0090] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 800°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0091] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0092] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1000°C until dense. The holding time is 10 h, and the heating and cooling rates are both 2°C / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCO.

[0093] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 1 and Figure 4 As shown, the obtained X-ray diffraction pattern was compared with the standard PDF card, and no impurities were found, indicating that the obtained film is a pure phase. The oxygen non-stoichiometry ratio δ of the material was determined to be 0.02 by iodometric titration. The surface morphology of the film was characterized using a HITACHI SU8200 scanning electron microscope, and the results are as follows. Figure 2a As shown, the grains are tightly packed together without bubbles or pores, indicating that the prepared film has good density.

[0094] Comparative Example 3

[0095] This comparative example provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0096] 1) Weigh 12.925g La2O3, 3.182g CuO and 0.1306g LaF3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0097] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 800°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0098] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0099] (4) The membrane green obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1000℃ to achieve densification. The holding time is 10h, and the heating and cooling rates are both 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOF. 0.05 (The oxygen nonstoichiometry ratio δ of the material was determined to be -0.08 by iodometric titration).

[0100] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 4 As shown, the obtained X-ray diffraction pattern is compared with the standard PDF card, indicating that the copper-based oxygen-permeable membrane material is a pure-phase membrane.

[0101] Comparative Example 4

[0102] This comparative example provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0103] 1) Weigh 12.816g La2O3, 3.182g CuO and 0.2612g LaF3 and add them to a ball mill jar, then add 30mL of acetone and ball mill at 350r / min for 24h;

[0104] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 800°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0105] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0106] (4) The membrane green obtained in step (3) is transferred to a corundum plate and then placed in a high-temperature muffle furnace for sintering at 1000℃ to achieve densification. The holding time is 10h, and the heating and cooling rates are both 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material, abbreviated as LCOF. 0.1 (The oxygen nonstoichiometry ratio δ of the material was determined to be -0.14 by iodometric titration).

[0107] X-ray diffraction analysis was performed on the above-mentioned copper-based oxygen-permeable membrane material, and the results are as follows: Figure 4 As shown, the obtained X-ray diffraction pattern is compared with the standard PDF card, indicating that the copper-based oxygen-permeable membrane material is a pure-phase membrane.

[0108] Comparative Example 5

[0109] This comparative example provides a copper-based oxygen-permeable membrane material, the preparation method of which specifically includes the following steps:

[0110] 1) Weigh 12.816g La2O3, 2.864g CuO, 0.576g MoO3 and 0.327g LaCl3 and add them to a ball mill jar. Then add 30mL of acetone and ball mill at 350r / min for 24h.

[0111] (2) After ball milling, the ball milled suspension was placed in a fume hood and air-dried naturally. After it was completely dried, the precursor powder was transferred to a muffle furnace and sintered at 800°C for 10 hours. The heating and cooling rates were 2°C / min to obtain the powder of the membrane material.

[0112] (3) Grind the powder of the membrane material obtained in step (2) in a mortar. After grinding, weigh 1.1g of the powder and place it in a stainless steel mold. Apply a pressure of 3Mpa for pre-pressing. Then place it in a micro isostatic press and hold it under a pressure of 7Mpa for 10min to obtain a membrane preform.

[0113] (4) The membrane preform obtained in step (3) is transferred to a corundum plate and then sintered in a high-temperature muffle furnace at 1000℃ for 10 hours, with a heating and cooling rate of 2℃ / min. After sintering, it is cooled to room temperature to obtain the copper-based oxygen-permeable membrane material. The oxygen non-stoichiometry ratio δ of the material is determined to be 0.11 by iodometric titration. This membrane material is denoted as La2Cu. 0.9 Mo 0.1 O4Cl 0.1 .

[0114] Experimental Example

[0115] The copper-based oxygen-permeable membrane materials prepared in each embodiment and comparative example were sequentially polished with 200-grit, 400-grit, 800-grit, 1200-grit, and 2000-grit silicon carbide sandpaper until a thickness of 0.5 mm was achieved (the membrane thickness was measured with vernier calipers during polishing to ensure that the target thickness of 0.5 mm required for testing was reached). Subsequently, they were ultrasonically cleaned with anhydrous ethanol to obtain the copper-based oxygen-permeable membrane material sheets for testing. The specific testing method is as follows:

[0116] The copper-based oxygen-permeable membrane material to be tested was sealed onto a test mold with an inner diameter of 16 mm using high-temperature ceramic adhesive. After 24 hours of curing, the airtightness of the device and membrane was tested. After confirming the airtightness, it was installed in a vertical tube furnace and heated to the required test temperature. After calibration with a soap bubble flow meter, air was introduced at a flow rate of 150 mL / min at the feed side and helium at a flow rate of 30 mL / min at the purge side. After an activation process of approximately 60 hours, the exhaust gas was introduced into an Agilent 7890A gas chromatograph to detect the gas components. After the oxygen permeability stabilized, the oxygen permeability temperature curve was tested, and the results are shown in Table 1. The oxygen permeability curves of the copper-based oxygen-permeable membrane materials prepared in Examples 1, 2, and 2 are shown in Table 1. Figure 5 As shown, by Figure 5 It can be seen that, under the same test conditions, compared with Comparative Example 2, the oxygen permeability of the oxygen permeable membrane prepared in Example 1 can be increased by up to 1.3 times, and the oxygen permeability of the oxygen permeable membrane prepared in Example 2 can be increased by up to 1.4 times.

[0117] Figure 6 The oxygen permeability of the copper-based oxygen-permeable membrane material prepared in Example 2 under the above test conditions was measured by switching between temperatures of 950°C and 875°C, and switching between He and CO2 purge gases at a rate of 30 mL / min. Figure 6 It can be seen that the oxygen permeability of the copper-based oxygen-permeable membrane material remains relatively stable when switching between different temperatures and different purge gases.

[0118] Table 1 Test Results

[0119]

[0120]

[0121] Note: J O2 This refers to oxygen permeability.

[0122] The data in the table above shows that in La2Cu 1-b M b O 4+δ X c The oxygen permeability of the material is improved after doping with anions Cl, but impurity phases are generated when the doping amount exceeds 0.2; and unlike perovskite materials where oxygen hole conduction is dominant, F ion doping does not improve the oxygen permeability of the material.

[0123] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A copper-based oxygen-permeable membrane material, characterized in that, The general chemical formula of the copper-based oxygen-permeable membrane material is La₂Cu. 1-b M b O 4+δ X c Where X is selected from Cl, Br and I; δ is a non-stoichiometric ratio, δ≤0.15, 0<c<0.2, 0<b≤0.2, and M is selected from Ni or W; The copper-based oxygen-permeable membrane material is a material that conducts oxygen vacancies and interstitial oxygen in a mixed manner.

2. A method for preparing the copper-based oxygen-permeable membrane material according to claim 1, characterized in that, Includes the following steps: 1) Mix the La source, Cu source, M source and X source, and dry to obtain precursor powder; 2) The precursor powder is calcined to obtain the powder of the membrane material; 3) Press the powder of the membrane material into shape and sinter it to obtain the copper-based oxygen-permeable membrane material.

3. The preparation method according to claim 2, characterized in that, In step 1), the mixing method is ball milling, during which an organic solvent is added.

4. The preparation method according to claim 3, characterized in that, The ball mill operates at a speed of 400-550 rpm for 3-24 hours.

5. The preparation method according to claim 2, characterized in that, In step 2), the calcination temperature is 700-900℃, the time is 5-20h, and the heating rate is 1-5℃ / min.

6. The preparation method according to claim 2, characterized in that, In step 3), the sintering temperature is 950-1200℃, the time is 5-20h, and the heating rate is 1-5℃ / min.

7. The preparation method according to claim 2, characterized in that, The La source is selected from inorganic salts or oxides of La; the copper source is selected from inorganic salts or oxides of copper; the X source is selected from lanthanum halide or copper halide; and the M source is selected from oxides or inorganic salts of M.

8. The preparation method according to claim 2, characterized in that, In step 1), the mixing method is ethylenediaminetetraacetic acid-citric acid mixed complexation, which includes the following steps: A) Mix aqueous solutions of La source, Cu source, M source and X source, add EDTA and citric acid, and then add an alkaline nonmetallic compound while stirring continuously to adjust the pH of the system to 6-8; to obtain a mixed solution. B) The mixed solution is heated and stirred to evaporate, yielding a gel.

9. The preparation method according to claim 8, characterized in that, In step 1), the drying process involves calcining the gel at 300-600°C for 2-5 hours.

10. The application of the copper-based oxygen-permeable membrane material prepared by the method of claim 1 or any one of claims 2-9 in the selective separation of oxygen, the construction of membrane reactors coupled with oxygen-related reactions, the reaction of methane oxidative coupling to ethylene, or the reaction of water cracking to produce hydrogen.

Images