Flexible MgAl for chemical warfare agent digestion2O4Preparation method of nanofiber membrane
阅读说明：本技术 一种用于化学战剂消解的柔性MgAl2O4纳米纤维膜的制备方法 (Flexible MgAl for chemical warfare agent digestion2O4Preparation method of nanofiber membrane ) 是由 单浩如 傅秋霞 刘其霞 葛建龙 张伟 季涛 高强 张瑜 于 2021-06-28 设计创作，主要内容包括：本发明涉及一种用于化学战剂消解的柔性MgAl-(2)O-(4)纳米纤维膜的制备方法,制备步骤包括：1)将镁源、铝源和晶粒抑制剂依次溶解在对应的溶剂中,先搅拌后加入无机凝胶增稠剂,再继续搅拌获得前驱体溶液；2)采用静电纺丝技术将前驱体溶液纺制成前驱体纤维膜；3)将上述前驱体纤维膜先在氮气或氩气气氛下煅烧,然后继续在空气气氛下进行低温热氧化处理得到柔性MgAl-(2)O-(4)纳米纤维膜。本发明制备的MgAl-(2)O-(4)纤维材料柔性好,纤维连续性及均匀性好,对化学战剂的消解效率高,在生化防护领域具有广阔的应用前景。(The invention relates to a flexible MgAl for digesting chemical warfare agents 2 O 4 The preparation method of the nanofiber membrane comprises the following preparation steps: 1) sequentially dissolving a magnesium source, an aluminum source and a crystal grain inhibitor in corresponding solvents, firstly stirring, then adding an inorganic gel thickener, and then continuously stirring to obtain a precursor solution; 2) spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology; 3) calcining the precursor fiber film in nitrogen or argon atmosphere, and then continuously performing low-temperature thermal oxidation treatment in air atmosphere to obtain the precursor fiber filmFlexible MgAl 2 O 4 A nanofiber membrane. MgAl prepared by the invention 2 O 4 The fiber material has good flexibility, good fiber continuity and uniformity, high digestion efficiency on chemical warfare agents and wide application prospect in the field of biochemical protection.)
1. Flexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane is characterized by comprising the following specific steps:
(1) sequentially dissolving a magnesium source, an aluminum source and a crystal grain inhibitor in corresponding solvents, firstly stirring for 10-60 min, then adding an inorganic gel thickener, and then continuously stirring for 10-90 min to obtain a precursor solution;
(2) spinning the precursor solution into a precursor fiber membrane by adopting electrostatic spinning;
(3) calcining the precursor fiber film in nitrogen or argon atmosphere, and then continuously performing low-temperature thermal oxidation treatment in air atmosphere to obtain flexible MgAl2O4A nanofiber membrane; the calcination process parameters are as follows: gradually increasing the temperature from room temperature to 450-800 ℃ under the atmosphere of nitrogen or argon, increasing the temperature at a speed of 1-10 ℃/min, keeping the temperature at the highest calcining temperature for 0-600 min, then placing the fiber film in the atmosphere of air, and performing low-temperature thermal oxidation treatment at 200-350 ℃ for 60-360 min to finally obtain the flexible MgAl2O4A nanofiber membrane.
2. The flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the magnesium source in the step (1) is one of anhydrous magnesium chloride, magnesium ethoxide, magnesium sulfate monohydrate, magnesium acetate tetrahydrate or magnesium nitrate hexahydrate; the aluminum source is one of anhydrous aluminum chloride, aluminum isopropoxide or aluminum nitrate nonahydrate.
3. Root of herbaceous plantThe flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the crystal grain inhibitor in the step (1) is one of stannic chloride, anhydrous stannous chloride, methyl orthosilicate, ethyl orthosilicate, zirconium acetate, zirconium oxychloride, tetrabutyl titanate, isopropyl titanate, titanium tetrachloride or antimony trichloride.
4. The flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the inorganic gel thickener in the step (1) is one of magnesium lithium silicate, sodium bentonite, organic bentonite, diatomite, attapulgite, aluminum silicate or fumed silica.
5. The flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the solvent in the step (1) respectively corresponds to the following components according to a magnesium source and an aluminum source:
anhydrous magnesium chloride and anhydrous aluminum chloride: water, methanol, ethanol, ethylene glycol, isopropanol, or N, N-dimethylformamide;
magnesium ethoxide and anhydrous aluminum chloride: water, ethanol or N, N-dimethylformamide;
magnesium sulfate monohydrate and anhydrous aluminum chloride: water, ethanol, glycerol or N, N-dimethylformamide;
magnesium acetate tetrahydrate with anhydrous aluminum chloride: water, methanol or ethanol;
magnesium nitrate hexahydrate and anhydrous aluminum chloride: water, methanol, ethanol or N, N-dimethylformamide;
anhydrous magnesium chloride and aluminum isopropoxide: methanol, ethanol, isopropanol, N-propanol, glycerol or N, N-dimethylformamide;
magnesium ethoxide and aluminum isopropoxide: ethanol or N, N-dimethylformamide;
magnesium sulfate monohydrate and aluminum isopropoxide: ethanol, glycerol or N, N-dimethylformamide;
magnesium acetate tetrahydrate with aluminum isopropoxide: methanol or ethanol;
magnesium nitrate hexahydrate and aluminum isopropoxide: methanol, ethanol or N, N-dimethylformamide;
anhydrous magnesium chloride with aluminum nitrate nonahydrate: water, methanol, ethanol, N-propanol, isopropanol or N, N-dimethylformamide;
magnesium ethoxide with aluminum nitrate nonahydrate: water, ethanol or N, N-dimethylformamide;
magnesium sulfate monohydrate and aluminum nitrate nonahydrate: water, ethanol, glycerol or N, N-dimethylformamide;
magnesium acetate tetrahydrate with aluminum nitrate nonahydrate: water, methanol or ethanol;
magnesium nitrate hexahydrate and aluminum nitrate nonahydrate: water, methanol, ethanol or N, N-dimethylformamide.
6. The flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the molar ratio of the magnesium source to the aluminum source in the step (1) is 1: 2; the molar ratio of the magnesium source to the crystal grain inhibitor is 1: 0.01-0.15; the ratio of the mass sum of the magnesium source and the aluminum source to the solvent is 10g: 10-70 mL; the molar ratio of the magnesium source to the inorganic gel thickener is 1: 0.05-0.4; the dynamic viscosity of the precursor solution is 0.5-10 Pa · s, and the conductivity is 5-80 mS/m.
7. The flexible MgAl for chemical warfare agent digestion of claim 12O4The preparation method of the nanofiber membrane is characterized in that the electrostatic spinning in the step (2) has the following technological parameters: controlling the humidity of a spinning section to be 60-90% during electrostatic spinning, filling the precursor solution at a flow rate of 1-15 mL/h at a spinning environment temperature of 10-45 ℃, connecting a spinning nozzle to a high-voltage power supply of 10-65 kV for spinning, and enabling the distance between a receiving device and the spinning nozzle to be 10-35 cm.
8. Flexible MgAl for chemical warfare agent digestion prepared by the preparation method of any one of claims 1 to 72O4Nano meterFibrous membrane, characterized in that said flexible MgAl is2O4The average fiber diameter of the nanofiber membrane is 20-400 nm, the relative standard deviation is 0.5-5%, the internal crystal grain size is 2-35 nm, and the flexible MgAl is2O4The softness of the nanofiber membrane is 10-75 mN.
9. The flexible MgAl for chemical warfare agent digestion of claim 82O4Application of the nanofiber membrane in catalytic degradation of mustard gas.
Technical Field
The invention belongs to the technical field of new materials, and particularly relates to flexible MgAl for digesting chemical warfare agents2O4A preparation method of a nanofiber membrane.
Background
The chemical warfare agent as a large-scale destructive weapon has the characteristics of violent toxicity, quick action, lasting toxic effect, wide killing range, difficult protection and treatment and the like, and can cause fatal damage to people, livestock and plants in a short time. Commonly used chemical warfare agents include blister agents, which are represented by mustard gas, and nerve agents, which are mainly tabun, sarin, soman, veex, etc. The chemical warfare agent has the characteristics of large-scale killing property, difficult degradation, lasting existence time in the environment and the like. Therefore, it is desirable to effectively degrade such materials to reduce the hazards associated with their use in warfare, production and storage.
At present, catalysts for degrading chemical warfare agents mainly comprise metal oxides, polyoxometallate, metal organic framework materials and the like, wherein the metal oxides are widely applied to degradation of the chemical warfare agents due to the characteristics of high catalytic activity, wide raw material sources, simple preparation process and the like. When the metal oxide is processed into nano-scale, the metal oxide is endowed with the characteristics of large specific surface area, large number of surface ions, high surface activity and the like, and the catalytic degradation performance on chemical warfare agents can be effectively improved. Of the numerous nano-metal oxides, MgAl2O4The surface of the nano material is provided with highly unsaturated bonds and a large number of ionized free radical groups, so that the nano material can provide an oxidation-reduction reaction between active metal sites and chemical warfare agents, and shows excellent toxin catalytic degradation performance. However, MgAl is currently being produced2O4The nano material is generally powdery, and has the problem of easy agglomeration in the use process, so that the nano material is difficult to be applied to the fields of gas filters, protective clothing and the like. Therefore, scientific research personnel adopt a method of supporting objects to load nano MgAl2O4Particles supported on Fibers, such as Ceramics International 41(2015) 12504-2O4Silicon carbide fiber and a preparation method thereof. The above-mentioned patent documents MgAl2O4The nano particles are respectively loaded on the organic or inorganic fibers, although the problem of easy agglomeration of the nano particles is solved to a certain extent, a large amount of MgAl2O4The particles are wrapped inside the fiber, so that the catalytic sites of the particles are reduced, the catalytic activity of the particles is reduced, and the particles are not beneficial to the efficient degradation of chemical warfare agents. MgAl2O4Compared with particles, the nano-fiber has the advantages of large length-diameter ratio, good continuity, high stability of aggregate structure and the like, and can effectively solve the bottleneck problem of the particle material in practical application. At present, methods for preparing inorganic nanofiber materials mainly comprise a hydrothermal method, a sol-gel method, a spinning method, a solid-liquid gas phase method, an electrostatic spinning method and the like, wherein the electrostatic spinning method has become one of the main technologies for preparing inorganic nanofiber materials at present due to the advantages of simple manufacturing device, wide range of spinnable raw materials, good adjustability of fiber structures and the like.
In the refractory material 49(2015)339-2O4A nanofiber; MgAl prepared by the same method is reported in the Chinese Journal of Materials Research 30(2016)116-2O4And (3) nano fibers. In the Journal of the Ceramic Society of Japan 126(2018) 128-containing 134, magnesium chloride and aluminum chloride are used as metal sources, polyvinylpyrrolidone is used as a polymer assistant, and a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer is used as a pore-foaming agentThe mesoporous MgAl is prepared by a coaxial electrostatic spinning method2O4A fiber. The above documents have obtained MgAl by the electrospinning technique2O4The nanofiber material is prepared by adding a large amount of high molecular polymers into a precursor solution, so that the content of inorganic components in the precursor solution is low, and MgAl is generated after calcination2O4The fiber yield is low, and the obtained MgAl2O4The fibers are mainly formed by particle accumulation. In addition, the high molecular polymer in the precursor fiber is decomposed stably in the calcining process, so that the fiber has poor continuity and more single fiber defects, and the flexible MgAl is difficult to obtain2O4And (3) nano fibers.
Therefore, a MgAl was developed2O4Flexible MgAl for degrading chemical warfare agent with high content, good flexibility, high catalytic efficiency and good structural stability2O4The nanofiber membrane and the preparation method thereof have very important significance.
Disclosure of Invention
The invention aims to provide flexible MgAl for digesting chemical warfare agents2O4The preparation method of the nanofiber membrane solves the problems that high-molecular polymers need to be added in the preparation process in the prior art, the continuity of fibers is poor, single fibers have many defects, and the fiber membrane is easy to break, and prepares the flexible MgAl for degrading the chemical warfare agent with good flexibility, high catalytic efficiency and good structural stability2O4A nanofiber membrane.
In order to achieve the purpose, the invention adopts the following technical scheme that the flexible MgAl is used for digesting the chemical warfare agent2O4The preparation method of the nanofiber membrane comprises the following steps:
(1) sequentially dissolving a magnesium source, an aluminum source and a grain inhibitor in corresponding solvents, firstly stirring for 10-60 min, then adding an inorganic gel thickener, and then continuously stirring for 10-90 min to obtain a precursor solution;
wherein the molar ratio of the magnesium source to the aluminum source is 1: 2; the molar ratio of the magnesium source to the crystal grain inhibitor is 1: 0.01-0.15; the ratio of the mass sum of the magnesium source and the aluminum source to the solvent is 10g: 10-70 mL; the molar ratio of the magnesium source to the inorganic gel thickener is 1: 0.05-0.4; the dynamic viscosity of the precursor solution is 0.5-10 Pa.s, and the conductivity is 5-80 mS/m;
(2) spinning the precursor solution into a precursor fiber membrane by adopting electrostatic spinning;
(3) calcining the precursor fiber film in nitrogen or argon atmosphere, and then continuously performing low-temperature thermal oxidation treatment in air atmosphere to obtain flexible MgAl2O4A nanofiber membrane;
the calcination process parameters are as follows: gradually increasing the temperature from room temperature to 450-800 ℃ under the atmosphere of nitrogen or argon, wherein the temperature increasing speed is 1-10 ℃/min, and the temperature is kept for 0-600 min at the highest calcining temperature. Then, the fiber film is placed in an air atmosphere to be subjected to low-temperature thermal oxidation treatment at the temperature of 200-350 ℃ for 60-360 min, and finally the flexible MgAl is prepared2O4A nanofiber membrane.
A flexible MgAl for chemical warfare agent digestion as described above2O4The preparation method of the nanofiber membrane comprises the following steps of (1) preparing a nanofiber membrane, wherein a magnesium source is one of anhydrous magnesium chloride, magnesium ethoxide, magnesium sulfate monohydrate, magnesium acetate tetrahydrate and magnesium nitrate hexahydrate; the aluminum source is one of anhydrous aluminum chloride, aluminum isopropoxide and aluminum nitrate nonahydrate.
A flexible MgAl for chemical warfare agent digestion as described above2O4The preparation method of the nanofiber membrane comprises the step of preparing the crystal grain inhibitor from one of stannic chloride, anhydrous stannous chloride, methyl orthosilicate, ethyl orthosilicate, zirconium acetate, zirconium oxychloride, tetrabutyl titanate, isopropyl titanate, titanium tetrachloride and antimony trichloride.
A flexible MgAl for chemical warfare agent digestion as described above2O4The preparation method of the nanofiber membrane comprises the step of preparing the inorganic gel thickener by using one of magnesium lithium silicate, sodium bentonite, organic bentonite, diatomite, attapulgite, aluminum silicate and fumed silica.
A flexible MgAl for chemical warfare agent digestion as described above2O4The preparation method of the nanofiber membrane comprises the step of electrostatic spinning, wherein the temperature of the spinning environment is 10 toAnd under the conditions of 45 ℃ and 60-90% of relative humidity, filling the precursor solution at a flow rate of 1-15 mL/h, and connecting a spinning nozzle to a high-voltage power supply of 10-65 kV for spinning, wherein the distance between the receiving device and the spinning nozzle is 10-35 cm.
A flexible MgAl for chemical warfare agent digestion as described above2O4The preparation method of the nanofiber membrane comprises the step of gradually increasing the temperature from room temperature to 450-800 ℃ in a tubular furnace under the atmosphere of nitrogen or argon, wherein the temperature increasing speed is 1-10 ℃/min, and the temperature is kept for 0-600 min at the highest calcination temperature. Then, the fiber film is placed in an air atmosphere to be subjected to low-temperature thermal oxidation treatment at the temperature of 200-350 ℃ for 60-360 min, and finally the flexible MgAl is prepared2O4A nanofiber membrane. MgAl obtained by calcining precursor fiber in the invention2O4The grain size inside the fiber is 2 to 35 nm.
The flexible MgAl prepared by the preparation method2O4Nanofiber membranes, flexible MgAl2O4The average diameter of fibers in the nanofiber membrane is 20-400 nm, the relative standard deviation is 0.5-5%, the grain size inside the fibers is 2-35 nm, and the fibers are flexible MgAl2O4The softness of the nanofiber membrane is 10-75 mN. Flexible MgAl as described above2O4Application of nanofiber membrane in degradation of mustard gas, and obtained nanofiber membrane has MgAl2O4Eutectic phase, effectively improves the chemical stability of the metal oxide, increases the catalytic active sites on the surface of the metal oxide and is beneficial to MgAl2O4The eutectic phase generates a large number of oxygen vacancies in the catalytic reaction, and then degrades the chemical warfare agent into a non-toxic product through reactions such as hydrolysis, surface complexation and the like. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane on 5 mu L of mustard gas simulator 2-chloroethyl ethyl sulfide (CEES) is more than 97.5%.
The diameter range of the fiber represents the thickness of the fiber, the fiber diameter is smaller, the softness of a single fiber is better, and the flexibility of a fiber film is improved; the relative standard deviation can be used to characterize the uniformity of the fiber diameter distribution, relative deviationThe smaller the fiber uniformity, the better; the grain size is closely related to the mechanical property of the single fiber, the smaller the grain size is, the higher the mechanical property of the single fiber is, the better the flexibility of the fiber film is, and meanwhile, the grain size reduction is beneficial to improving MgAl2O4Catalytic digestion of chemical warfare agents by the fibers.
The invention principle of the preparation method provided by the invention is as follows:
according to the invention, a magnesium source, an aluminum source and a grain inhibitor are sequentially dissolved in a corresponding solvent to generate metal cations, then an inorganic gel thickener is added and uniformly stirred, the solvent gradually permeates into lamella of the inorganic gel thickener to gradually generate swelling, meanwhile, under the action of shearing force, the lamella of the inorganic gel thickener gradually dissociates, a large amount of metal cations are adsorbed by free monolithic layers, and the lamella are mutually lapped under the action of the solvent to further form a three-dimensional network structure, so that the viscoelasticity of a precursor solution is increased, and the spinnability is enhanced. And then, spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 60-90% in the spinning process, so that the bonding fastness between the thickener lamellar layers is further increased, the collapse of a three-dimensional reticular lamellar structure in the jet flow rapid stretching process is avoided, and the adsorption force between the surface of the thickener lamellar layer and metal ions is kept stable, so that the metal ions in the precursor fiber are uniformly distributed, the single fiber continuity is better, and the fiber diameter is uniform. Calcining the precursor fiber film in nitrogen or argon atmosphere to promote the rapid decomposition of the magnesium source and the aluminum source, and rapidly fusing crystal grains to form MgAl2O4The eutectic phase, in which the cations in the grain inhibitor can replace magnesium ions or aluminum ions in the eutectic phase, causes the grain growth rate and grain boundary slip of the eutectic phase to be limited, thereby making the grain size thereof smaller. Subsequently, the MgAl is removed by low-temperature thermal oxidation treatment under the air atmosphere2O4Residual carbon in the fiber is finally obtained to obtain MgAl with excellent flexibility2O4And (3) nano fibers.
Has the advantages that:
(1) the invention provides a method forFlexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane does not need to add a high-molecular spinning aid, and a three-dimensional net structure is formed through the processes of swelling, dissociation, adsorption, self-assembly and the like of an inorganic gel thickener in a solution, so that the viscoelasticity and spinnability of a precursor solution are improved, the content of a magnesium source and an aluminum source in precursor fibers is high, and MgAl is MgAl2O4The nano-fiber has high yield and good fiber continuity and is easy for industrialized production;
(2) the invention provides flexible MgAl for digesting chemical warfare agents2O4The preparation method of the nanofiber membrane comprises the steps of firstly calcining a precursor fiber membrane in the atmosphere of nitrogen or argon, and then continuously carrying out low-temperature thermal oxidation treatment in the atmosphere of air to obtain MgAl with eutectic phase2O4The nanofiber is not used for simply mixing two oxides, so that the catalytic activity of the material is effectively improved;
(3) the flexible MgAl for digesting chemical warfare agents obtained by the preparation method provided by the invention2O4The nanofiber membrane has good flexibility and chemical warfare agent digestion performance.
The specific implementation mode is as follows:
the invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
Flexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane comprises the following specific steps:
(1) dissolving magnesium source anhydrous magnesium chloride, aluminum source anhydrous aluminum chloride and a crystal grain inhibitor stannic chloride in solvent water in sequence, stirring for 20min, adding an inorganic gel thickener lithium magnesium silicate, and continuing to stir for 60min, wherein the molar ratio of the magnesium source, the aluminum source, the crystal grain inhibitor and the inorganic gel thickener in the solution is 1:2:0.04:0.16, the mass ratio of the magnesium source and the aluminum source to the solvent is 10g:30mL, and uniformly mixing to prepare a uniform stable precursor solution with dynamic viscosity of 8.7 Pa.s and conductivity of 55.6 mS/m.
(2) Spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 80% during electrostatic spinning; the technological parameters of electrostatic spinning are as follows: the environment temperature is 25 ℃, the perfusion speed is 2mL/h, the voltage is 49kV, and the distance between the receiving device and the spinning nozzle is 23 cm;
(3) the precursor fiber film is firstly gradually heated to 650 ℃ from room temperature under the nitrogen atmosphere, the heating speed is 2 ℃/min, and the precursor fiber film is kept for 360min at the highest calcining temperature. Then, the fiber film is placed in the air atmosphere to be subjected to low-temperature thermal oxidation treatment for 240min at the temperature of 300 ℃, and finally the flexible MgAl is prepared2O4A nanofiber membrane.
Reference national standard GB/T34520.2-2017 "continuous silicon carbide fiber testing method part 2: measuring the diameter of a single fiber to obtain MgAl2O4The average diameter of the nanofibers was 230nm with a relative standard deviation of the diameters of 1.5%. MgAl inside the fiber is measured according to GB/T23413-2009 method for measuring grain size and microscopic strain of nano material by X-ray diffraction line broadening method2O4The grain size was 17 nm. The flexible MgAl is measured according to the national standard GB/T8942-2016 paper softness determination2O4The softness of the nanofiber membrane was 36 mN.
To characterize the Flexible MgAl2O4The degradation rate of the nanofiber membrane on mustard gas simulator CEES is firstly established by utilizing an ultraviolet-visible spectrophotometer according to a Frank method, and then 5mg of MgAl is taken2O4The fiber membrane was placed in a centrifuge tube, and 45. mu.L of CEES in n-hexane (5. mu.L CEES + 40. mu.L n-hexane) was added thereto, and the fiber membrane was sufficiently contacted with the toxicant by shaking with a vortex shaker for 5 min. Extracting residual CEES in the solution with n-hexane, measuring its absorbance at 445nm with ultraviolet-visible spectrophotometer, calculating residual CEES concentration according to standard curve equation, and further calculating MgAl2O4Degradation rate of the fibrous membrane to CEES. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane on 5 mul of mustard gas simulator CEES is 97.9%.
Example 2
Flexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane comprises the following specific steps:
(1) sequentially dissolving magnesium ethylate, aluminum source anhydrous aluminum chloride and crystal grain inhibitor methyl orthosilicate in solvent ethanol, stirring for 30min, adding an inorganic gel thickener sodium bentonite, and continuing to stir for 50min, wherein the molar ratio of the magnesium source, the aluminum source, the crystal grain inhibitor and the inorganic gel thickener in the solution is 1:2:0.05:0.28, the ratio of the magnesium source, the aluminum source and the mixed solvent is 10g:42mL, and uniformly mixing to prepare a uniform stable precursor solution with dynamic viscosity of 8.1 Pa.s and conductivity of 46.5 mS/m;
(2) spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 85% during electrostatic spinning; the technological parameters of electrostatic spinning are as follows: the environment temperature is 27 ℃, the perfusion speed is 1mL/h, the voltage is 42kV, and the distance between the receiving device and the spinning nozzle is 25 cm;
(3) the precursor fiber film is firstly gradually heated to 700 ℃ from room temperature under the argon atmosphere, the heating speed is 1 ℃/min, and the precursor fiber film is kept for 60min at the highest calcining temperature. Subsequently, the fiber film is placed in the air atmosphere to be subjected to low-temperature thermal oxidation treatment at 300 ℃ for 270min to obtain flexible MgAl2O4A nanofiber membrane.
MgAl was measured by the same Performance test method as example 12O4The average diameter of the nano-fiber is 270nm, the relative standard deviation of the diameters is 2.3 percent, and MgAl in the fiber2O4The grain size is 19nm, and the MgAl is flexible2O4The softness of the nanofiber membrane was 38 mN. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane on 5 mul of mustard gas simulator CEES is 97.6%.
Example 3
Flexible MgAl for chemical warfare agent digestion2O4Preparation method of nanofiber membraneThe method comprises the following specific steps:
(1) sequentially dissolving magnesium source magnesium sulfate monohydrate, aluminum source anhydrous aluminum chloride and crystal grain inhibitor zirconium acetate in solvent glycerol, stirring for 35min, adding inorganic gel thickener diatomite, and continuing to stir for 75min, wherein the molar ratio of the magnesium source to the aluminum source to the crystal grain inhibitor to the inorganic gel thickener in the solution is 1:2:0.06:0.12, the mass ratio of the magnesium source to the aluminum source to the solvent is 10g:40mL, and uniformly mixing to prepare uniform stable precursor solution with dynamic viscosity of 6.8 Pa.s and conductivity of 38.9 mS/m;
(2) spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 88% during electrostatic spinning; the technological parameters of electrostatic spinning are as follows: the environment temperature is 24 ℃, the perfusion speed is 2mL/h, the voltage is 49kV, and the distance between the receiving device and the spinning nozzle is 26 cm;
(3) the precursor fiber film is firstly gradually heated to 800 ℃ from room temperature under the nitrogen atmosphere, the heating speed is 5 ℃/min, and the precursor fiber film is kept for 180min under the highest calcining temperature. Then, the fiber film is placed in the air atmosphere to be subjected to low-temperature thermal oxidation treatment for 180min at the temperature of 280 ℃, and finally the flexible MgAl is prepared2O4A nanofiber membrane.
MgAl was measured by the same Performance test method as example 12O4The average diameter of the nano-fiber is 270nm, the relative standard deviation of the diameters is 2.3 percent, and MgAl in the fiber2O4The grain size is 25nm, and the MgAl is flexible2O4The softness of the nanofiber membrane was 51 mN. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane on 5 mul of mustard gas simulator CEES is 97.6%.
Example 4
Flexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane comprises the following specific steps:
(1) sequentially dissolving magnesium source tetrahydrate magnesium acetate, aluminum source anhydrous aluminum chloride and crystal grain inhibitor tetrabutyl titanate in a solvent methanol, stirring for 45min, adding an inorganic gel thickener aluminum silicate, and continuously stirring for 45min, wherein the molar ratio of the magnesium source to the aluminum source to the crystal grain inhibitor to the inorganic gel thickener is 1:2:0.04:0.26, the ratio of the magnesium source to the aluminum source to the mixed solvent is 10g:36mL, and uniformly mixing to prepare a uniform stable precursor solution with dynamic viscosity of 8.9 pas and conductivity of 57.3 mS/m;
(2) spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 79% during electrostatic spinning; the technological parameters of electrostatic spinning are as follows: the environment temperature is 27 ℃, the perfusion speed is 3.5mL/h, the voltage is 55kV, and the distance between the receiving device and the spinning nozzle is 29 cm;
(3) the precursor fiber film is firstly gradually heated to 700 ℃ from room temperature under the nitrogen atmosphere, the heating speed is 5 ℃/min, and the precursor fiber film is kept for 120min at the highest calcining temperature. Then, the fiber film is placed in the air atmosphere to be subjected to low-temperature thermal oxidation treatment for 120min at 320 ℃, and finally the flexible MgAl is prepared2O4A nanofiber membrane.
MgAl was measured by the same Performance test method as example 12O4The average diameter of the nano-fiber is 180nm, the relative standard deviation of the diameters is 1.8 percent, and MgAl in the fiber2O4The grain size is 13nm, and the MgAl is flexible2O4The softness of the nanofiber membrane was 22 mN. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane on 5 mul of mustard gas simulator CEES is 98.7%.
Example 5
Flexible MgAl for chemical warfare agent digestion2O4The preparation method of the nanofiber membrane comprises the following specific steps:
(1) sequentially dissolving magnesium source hexahydrate magnesium nitrate, aluminum source anhydrous aluminum chloride and crystal grain inhibitor antimony trichloride in a mixed solvent ethanol/N, N-dimethylformamide, stirring for 40min, adding inorganic gel thickener fumed silica, and continuously stirring for 100min, wherein the molar ratio of the magnesium source, the aluminum source, the crystal grain inhibitor and the inorganic gel thickener in the solution is 1:2:0.08:0.24, the mass ratio of the magnesium source and the aluminum source to the solvent is 10g:56mL, the volume ratio of ethanol to N, N-dimethylformamide is 1:1, and uniformly mixing to obtain a uniform stable precursor solution with dynamic viscosity of 7.5 pas and electric conductivity of 53.4 mS/m;
(2) spinning the precursor solution into a precursor fiber membrane by adopting an electrostatic spinning technology, and controlling the humidity of a spinning interval to be 82% during electrostatic spinning; the technological parameters of electrostatic spinning are as follows: the environment temperature is 28 ℃, the perfusion speed is 1mL/h, the voltage is 32kV, and the distance between the receiving device and the spinning nozzle is 20 cm;
(3) the precursor fiber film is firstly gradually heated to 800 ℃ from room temperature under the nitrogen atmosphere, the heating speed is 5 ℃/min, and the precursor fiber film is kept for 180min under the highest calcining temperature. Then, the fiber film is placed in the air atmosphere to be subjected to low-temperature thermal oxidation treatment at 340 ℃ for 90min, and finally the flexible MgAl is prepared2O4A nanofiber membrane.
MgAl was measured by the same Performance test method as example 12O4The average diameter of the nano-fiber is 210nm, the relative standard deviation of the diameters is 1.9 percent, and MgAl in the fiber2O4The grain size is 16nm, and the MgAl is flexible2O4The softness of the nanofiber membrane was 30 mN. 5mg of flexible MgAl within 30min2O4The degradation rate of the nanofiber membrane to 5 mul of mustard gas simulated CEES was 98.1%.
Examples 6 to 15
Examples 6-15 (tables 1 and 2) preparation procedures were the same as example 1, wherein the precursor solution parameters, electrospinning and calcining parameters, flexible MgAl2O4The fiber film performance parameters are shown in the table. (note: stirring time 1 is the stirring time after the magnesium source, the aluminum source and the crystal grain inhibitor are added into the solvent, and stirring time 2 is the stirring time after the inorganic gel thickener is added)
TABLE 1
TABLE 2