Composite fiber membrane for removing hydrogen fluoride gas, preparation method, application and regeneration method

Abstract

The invention relates to the technical field of hydrogen fluoride-containing waste gas treatment, in particular to a composite fiber membrane for removing hydrogen fluoride gas as well as a preparation method, application and a regeneration method. The composite fiber membrane for removing hydrogen fluoride gas comprises a matrix layer and a microporous membrane layer, the matrix layer is used for modifying a matrix material by utilizing an amino functional reagent dispersed in the matrix material under hot-pressing treatment; meanwhile, one end of the amino functional reagent is embedded in the microporous membrane layer, so that the matrix layer is bonded with the microporous membrane layer. According to the composite fiber membrane, aerosol particles are filtered through the microporous membrane layer, particulate matter or aerosol in hydrogen fluoride gas is effectively removed, and the hydrogen fluoride gas is efficiently and rapidly adsorbed through the aminated fibers of the matrix layer. And the matrix material is modified through the amino functional reagent under the hot pressing condition, so that the matrix layer and the microporous membrane layer are tightly bonded, the fluorine removal efficiency is improved, and the problem that the hydrogen fluoride waste gas treatment efficiency is not high due to the fact that an existing adsorption material is interfered by particulate matter or aerosol is solved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen fluoride-containing waste gas treatment, and in particular to a composite fiber membrane for removing hydrogen fluoride gas and a preparation method, use and regeneration method thereof. Background Art

[0002] In the chemical industry, hydrogen fluoride, as an important raw material and intermediate, is widely used in many fields such as smelting, fluoride product processing, glass manufacturing, semiconductor production, and solar cell manufacturing. However, the widespread use of hydrogen fluoride has also brought serious environmental pollution and health risks. Hydrogen fluoride is a colorless, odorless, highly toxic inorganic gas under normal conditions. It is extremely corrosive and has great harm to human skin, mucous membranes, and respiratory system. Acute exposure to hydrogen fluoride can cause deep chemical burns, forming stubborn necrosis or ulcers. At a hydrogen fluoride concentration of 400 mg / m 3 ~430 mg / m 3 If the concentration of hydrogen fluoride is too low, it may even cause acute poisoning and death. If you are exposed to low concentrations of hydrogen fluoride for a long time, you may suffer from serious health problems such as inflammation of the eyes, nose and throat, symptoms of the nervous system, and bone damage.

[0003] In addition, the emission of hydrogen fluoride gas into the atmosphere can also cause acid rain, causing long-term damage to soil, water sources and ecosystems. Based on this, how to effectively treat hydrogen fluoride pollutants, especially waste gas containing hydrogen fluoride aerosols, has become an important issue that needs to be urgently addressed in the industrial and environmental protection fields.

[0004] At present, the methods for industrial treatment of hydrogen fluoride waste gas mainly include water and alkali solution absorption method, activated carbon absorption method, γ-Al 2 O 3 Absorption method, calcium oxide absorption method, hydrotalcite absorption method, etc. The above treatment methods mainly use water, alkali solution, activated carbon, γ-Al2O3, calcium oxide, hydrotalcite and other adsorption materials to adsorb hydrogen fluoride. However, since hydrogen fluoride waste gas often contains particulate matter or aerosol, the presence of these particulate matter or aerosol will interfere with the adsorption effect of existing adsorption materials on hydrogen fluoride, resulting in low treatment efficiency of hydrogen fluoride waste gas. Summary of the invention

[0005] In order to solve the problem that the existing adsorption materials are interfered by particulate matter or aerosols, resulting in low efficiency in treating hydrogen fluoride waste gas, the object of the present invention is to provide a composite fiber membrane for removing hydrogen fluoride gas and a preparation method and a regeneration method thereof.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] The first aspect of the present invention provides a composite fiber membrane for removing hydrogen fluoride gas, the composite fiber membrane comprising a substrate layer and a microporous membrane layer; the substrate layer is obtained by modifying the substrate material under hot pressing treatment using an amino functional reagent dispersed inside the substrate material; at the same time, one end of the amino functional reagent is embedded in the microporous membrane layer to allow the substrate layer to bond with the microporous membrane layer; the substrate material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the acrylonitrile monomer content in the substrate material is 10wt% to 99wt%; the amino functional reagent is an amine compound containing at least two amino groups.

[0008] The composite fiber membrane of the present invention filters aerosol particles through the microporous membrane layer, effectively removes particulate matter or aerosol in the hydrogen fluoride removal gas, and at the same time, the amino-modified fibers of the base layer efficiently and quickly adsorb hydrogen fluoride gas. In addition, the present invention also modifies the base material under hot pressing conditions by using an amino functional reagent, which not only improves the utilization efficiency of the amino functional reagent, but also achieves close adhesion between the base layer and the microporous membrane layer, thereby further improving the overall defluorination efficiency, and solving the problem that the existing adsorption material is interfered by particulate matter or aerosol, resulting in low efficiency in treating hydrogen fluoride waste gas.

[0009] The invention replaces the adhesive between the substrate layer and the microporous membrane layer while using the amino functional reagent for modification, thereby improving the utilization efficiency of the amino functional reagent.

[0010] Preferably, the matrix material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the amino functional reagent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine and p-phenylenediamine; the microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polytetrafluoroethylene microporous membrane; the pore size of the microporous membrane material is 0.1μm to 1μm.

[0011] In the present invention, the matrix material is preferably polyacrylonitrile fiber or amino polyacrylonitrile fiber, wherein the content of acrylonitrile monomer in the matrix material is greater than 10wt%; the amino polyacrylonitrile fiber is an amino functional fiber pre-modified with polyacrylonitrile fiber using an amino functional reagent, and the specific preparation method can refer to CN114042437B.

[0012] Preferably, the ion exchange capacity of the composite fiber membrane is 1 mmol / g to 6 mmol / g; the resistance of the composite fiber membrane when the air linear velocity is 5.33 cm / s is less than 250 Pa. Preferably, the ion exchange capacity of the composite fiber membrane is 3 mmol / g to 6 mmol / g; the resistance of the composite fiber membrane when the air linear velocity is 5.33 cm / s is less than 120 Pa.

[0013] A second aspect of the present invention provides a method for preparing a composite fiber membrane for removing hydrogen fluoride gas, comprising the following steps:

[0014] The substrate material is placed in a solution containing an amino functional reagent to fully swell the substrate material to obtain a swollen substrate material; the substrate material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the substrate material is 10wt% to 99wt%; the amino functional reagent is an amine compound containing at least two amino groups; a microporous membrane material is covered on the swollen substrate material and subjected to a hot pressing treatment to modify the substrate material with the amino functional reagent, and at the same time, one end of the amino functional reagent is embedded in the microporous membrane layer to bond the formed substrate layer and the microporous membrane layer to obtain a composite fiber membrane for removing hydrogen fluoride gas.

[0015] The composite fiber membrane prepared by the present invention mainly uses the general formula of modifying the matrix material with an amino functional reagent to bond the matrix layer and the microporous membrane layer. The amino groups on the amino functional reagent react with the cyano groups in the matrix material, so that part of the amino functional reagent can form a structure in which one end is grafted with the matrix material and the other end is embedded in the microporous membrane pores, and the structure is bonded together by chemical bonding and physical bonding.

[0016] In addition, the present invention adopts a hot pressing method to prepare the composite fiber membrane, which improves the fiber grafting degree while bonding the base layer and the microporous membrane layer, greatly shortens the preparation time of the composite fiber membrane, and improves production efficiency.

[0017] Preferably, the matrix material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the amino functional reagent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine and p-phenylenediamine; the microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polytetrafluoroethylene microporous membrane; the pore size of the microporous membrane material is 0.1μm to 1μm; the resistance of the microporous membrane material at an air linear velocity of 5.33cm / s is <200Pa.

[0018] Preferably, the resistance of the microporous membrane material is less than 100 Pa when the air linear velocity is 5.33 cm / s.

[0019] Preferably, the conditions for the hot pressing treatment are: temperature of 60°C to 140°C, time of 1 min to 120 min, and pressure of 0 MPa to 30 MPa. Preferably, the conditions for the hot pressing treatment are: temperature of 80°C to 110°C, time of 1 min to 60 min, and pressure of 0 MPa to 10 MPa.

[0020] In the present invention, the modification is carried out at a temperature above 60°C, and no reaction occurs under normal temperature swelling.

[0021] Preferably, the solution containing the amino functional reagent is obtained by dissolving the amino functional reagent in a solvent; in the solution containing the amino functional reagent, the mass concentration of the amino functional reagent is 1% to 50%; the solvent is at least one of water, methanol, ethanol, propanol, butanol, ethylene glycol and propylene glycol; the mass percentage of the solvent contained in the swollen matrix material is 10% to 60%.

[0022] Preferably, in the solution containing the amino functional agent, the mass concentration of the amino functional agent is preferably 5% to 40%, more preferably 20% to 40%, and more preferably 20% to 30%.

[0023] Preferably, the mass percentage of the solvent contained in the swollen matrix material is 10% to 30%.

[0024] The third aspect of the present invention provides a use of the composite fiber membrane for removing hydrogen fluoride gas as described in the first aspect as a fluoride ion adsorption material for hydrogen fluoride gas treatment.

[0025] Preferably, the hydrogen fluoride gas contains hydrogen fluoride aerosol with a particle size of 0.3 μm to 1 μm.

[0026] The composite fiber membrane of the present invention has a treatment efficiency of more than 99% for hydrogen fluoride particles with a size of 0.3 μm or more and a treatment efficiency of more than 100 mg / m 3 The purification efficiency of hydrogen fluoride gas is greater than 99%.

[0027] The fourth aspect of the present invention provides a method for regenerating the composite fiber membrane for removing hydrogen fluoride gas according to the first aspect, comprising the following steps:

[0028] An inorganic alkali solution with a mass concentration of 0.5% to 10% is used as the regeneration solution; the used composite fiber membrane is immersed in the inorganic alkali solution, or the used composite fiber membrane is sprayed with the inorganic alkali solution; the inorganic alkali in the inorganic alkali solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

[0029] Preferably, the regeneration solution is an inorganic alkaline solution with a mass concentration of 0.5% to 3%.

[0030] The composite fiber membrane regeneration method provided by the present invention can select shutdown immersion regeneration or non-stop online spraying regeneration, has the characteristics of fast regeneration speed and simple regeneration method, and non-stop online regeneration is suitable for industrial continuous operation.

[0031] Beneficial effects of the present invention:

[0032] 1. The composite fiber membrane of the present invention mainly combines the low-resistance and high-efficiency particle filtration characteristics of the microporous membrane layer and the sensitive and high-efficiency hydrogen fluoride adsorption characteristics of the multi-amino functional fibers of the substrate layer. At the same time, the substrate material is modified by amino functional reagents under hot pressing conditions, which not only improves the utilization efficiency of the reagents, but also achieves close adhesion between the substrate layer and the microporous membrane layer, greatly improves the fluorine removal efficiency of the composite fiber membrane, and solves the problem that the existing adsorption materials are interfered by particulate matter or aerosols, resulting in low efficiency in treating hydrogen fluoride waste gas.

[0033] 2. The composite fiber membrane of the present invention has a treatment efficiency of more than 99% for hydrogen fluoride particles larger than 0.3 μm and 100 mg / m 3 The purification efficiency of hydrogen fluoride gas is greater than 99%.

[0034] 3. The composite fiber membrane prepared by the present invention mainly uses the general formula of modifying the matrix material with an amino functional reagent to bond the matrix layer and the microporous membrane layer. Among them, the amino group on the amino functional reagent reacts with the cyano group in the matrix material, so that part of the amino functional reagent can form a structure in which one end is grafted with the matrix material and the other end is embedded in the pores of the microporous membrane, and is bonded together by chemical bonding and physical bonding.

[0035] 4. The present invention adopts a hot pressing method to prepare the composite fiber membrane, which not only bonds the substrate layer and the microporous membrane layer, but also improves the degree of fiber grafting, greatly shortens the preparation time of the composite fiber membrane, and improves production efficiency. It has the characteristics of low cost, simple preparation process, and suitability for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of a composite fiber membrane provided in accordance with one embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the experimental device for purification and adsorption of hydrogen fluoride using composite fiber membrane.

[0038] Figure 3 This is a graph showing how the removal rate of hydrogen fluoride gas or particles larger than 0.3 μm by the composite fiber membrane according to one embodiment of the present invention changes with the number of regenerations.

[0039] Figure 4 It is the infrared spectrum of the base material before and after treatment in Example 1 of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0042] like Figure 1 The present invention provides a composite fiber membrane for removing hydrogen fluoride gas, the composite fiber membrane comprising a substrate layer and a microporous membrane layer; the substrate layer is obtained by modifying the substrate material under hot pressing treatment using an amino functional reagent dispersed inside the substrate material; at the same time, one end of the amino functional reagent is embedded in the microporous membrane layer to allow the substrate layer to adhere to the microporous membrane layer; the substrate material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the acrylonitrile monomer content in the substrate material is 10wt% to 100wt%; the amino functional reagent is an amine compound containing at least two amino groups.

[0043] The preparation method of the composite fiber membrane for removing hydrogen fluoride gas of the present invention mainly uses polyacrylonitrile fiber or amino polyacrylonitrile fiber as a matrix, uses one or more polyamine compounds selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, and p-phenylenediamine as amino functional reagents, and uses microporous membranes such as polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane, and polytetrafluoroethylene microporous membrane as membrane layer materials. First, the matrix is ​​placed in an amino functional reagent solvent to fully swell and then the excess solvent is removed, and the swollen matrix material is covered with a membrane layer material, and a flat hot press is used for heat pressing treatment without or with a small amount of hot melt adhesive, and after the heat pressing treatment is completed, the composite fiber membrane for removing hydrogen fluoride gas is prepared by washing and drying.

[0044] Among them, the polypropylene microporous membrane is recorded as PP microporous membrane; the polyester microporous membrane is recorded as PET microporous membrane; the polyamide microporous membrane is recorded as PA microporous membrane; the polytetrafluoroethylene microporous membrane is recorded as PTFE microporous membrane; and the polytetrafluoroethylene microporous membrane is recorded as PVDF microporous membrane.

[0045] The present invention also provides a use of a composite fiber membrane for removing hydrogen fluoride gas and a regeneration method. The composite fiber membrane for removing hydrogen fluoride gas of the present invention has the advantages of high sensitivity, high removal rate, low system resistance, easy regeneration, etc., can be operated continuously for a long time, and is suitable for treating hydrogen fluoride gas in various fields and of various scales. The preparation method of the present invention has widely available raw materials, low cost, simple process, and is suitable for large-scale industrial production and use, especially suitable for industries such as semiconductor manufacturing that require high-precision treatment of hydrogen fluoride gas.

[0046] It should be noted that the composite fiber membrane prepared by the present invention mainly uses the general formula of modifying the matrix material with an amino functional reagent to bond the matrix layer and the microporous membrane layer. Among them, the amino group on the amino functional reagent reacts with the cyano group in the matrix material, so that part of the amino functional reagent can form a structure with one end grafted to the matrix material and the other end embedded in the pores of the microporous membrane, and bonded together by chemical bonding and physical bonding. The reaction of the amino group on the amino functional reagent with the cyano group in the matrix material is carried out at a temperature above 60°C, and no reaction occurs under normal temperature swelling. The step of swelling the matrix material can be carried out at room temperature or at 20-50°C, and the normal temperature is 25°C±5°C.

[0047] The technical solution of the present invention is further described below through specific embodiments.

[0048] In the following examples, the methods described are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0049] The polyacrylonitrile fiber with acrylonitrile monomer content greater than 80 wt % was purchased from Qilu Petrochemical.

[0050] The amino polyacrylonitrile fiber is made in the laboratory. The specific preparation method is carried out with reference to patent application CN114042437B. The pH is neutral, that is, pH=7.

[0051] Test equipment: Fabric air permeability tester, Jinan Languang Electromechanical Technology Co., Ltd., TQD-G1A. Flatbed heat press, Guangzhou Har Technology Co., Ltd., HTYP-30. Aerosol generator, Qingdao Lubo Jianye Environmental Protection Technology Co., Ltd., LB-3311. Filter absorber nondestructive testing system, Beijing Aerospace Yilai Electronic Technology Co., Ltd., VRD-FO1. The remaining equipment is commercially available unless otherwise specified.

[0052] Example 1

[0053] A method for preparing a composite fiber membrane for removing hydrogen fluoride gas comprises the following steps:

[0054] Step 1, swelling of the base material: polyacrylonitrile fiber with an acrylonitrile monomer content greater than 80wt% is selected as the base material, and the base material is placed in a diethylenetriamine aqueous solution with a mass concentration of 40%, and soaked at room temperature for 12 hours to fully swell the base material, and after removing excess solvent, a swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0055] Step 2, preparation of composite fiber membrane for removing hydrogen fluoride gas: covering the swollen base material with a layer of polypropylene microporous membrane. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is less than 100 Pa when the air linear velocity is 5.33 cm / s.

[0056] The substrate material covered with the polypropylene microporous membrane was subjected to a heat pressing treatment at a temperature of 95°C and a pressure of 1 MPa for 60 minutes using a flat hot press to modify the substrate material with an amino functional reagent, and at the same time, one end of the amino functional reagent was embedded in the microporous membrane layer to bond the formed substrate layer and the microporous membrane layer. After the heat pressing treatment, the fiber was washed with water until the pH value was neutral, and dried at 60°C to a constant weight to obtain a composite fiber membrane for removing hydrogen fluoride gas.

[0057] Figure 4 : is the infrared spectrum of the base material before and after the treatment in Example 1 of the present invention. Among them, the commercially available polyacrylonitrile fiber is the base material before the treatment; the modified polyacrylonitrile fiber after the treatment is the base material after the treatment by the method of Example 1.

[0058] like Figure 4 , 2242nm is the nitrile peak, and the peak intensity weakened after treatment, proving that the reaction with the nitrile group occurred. 3274nm is the NH stretching peak, 1635nm, 1560nm and 1237nm are the CN double bond and CN single bond stretching peaks, proving that the grafting is successful.

[0059] Example 2

[0060] A method for preparing a composite fiber membrane for removing hydrogen fluoride gas comprises the following steps:

[0061] Step 1, swelling of the base material: amino polyacrylonitrile fiber with an acrylonitrile monomer content greater than 10wt% is selected as the base material, and the base material is placed in a triethylenetetramine glycol solution with a mass concentration of 20%, and soaked at 50°C for 3 hours to fully swell the base material, and after removing excess solvent, a swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0062] Step 2, preparation of composite fiber membrane for removing hydrogen fluoride gas: covering the swollen base material with a layer of polypropylene microporous membrane. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is less than 100 Pa when the air linear velocity is 5.33 cm / s.

[0063] The substrate material covered with the microporous membrane material was subjected to a heat press treatment at a temperature of 100°C and a pressure of 3Mpa for 20 minutes using a flat hot press machine to modify the substrate material with an amino functional reagent, and at the same time, one end of the amino functional reagent was embedded in the microporous membrane layer to bond the formed substrate layer and the microporous membrane layer. After the heat press treatment, the fiber was washed with water until the pH value was neutral, and dried at 60°C to a constant weight to obtain a composite fiber membrane for removing hydrogen fluoride gas.

[0064] Example 3

[0065] A method for preparing a composite fiber membrane for removing hydrogen fluoride gas comprises the following steps:

[0066] Step 1, swelling of the base material: amino polyacrylonitrile fiber with an acrylonitrile monomer content greater than 80wt% is selected as the base material, and the base material is placed in a diethylenetriamine aqueous solution with a mass concentration of 20%, and soaked at 40°C for 12 hours to fully swell the base material, and after removing excess solvent, a swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0067] Step 2, preparation of composite fiber membrane for removing hydrogen fluoride gas: covering the swollen base material with a layer of polyvinylidene fluoride microporous membrane. The pore size of the polyvinylidene fluoride microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is less than 100 Pa when the air linear velocity is 5.33 cm / s.

[0068] The substrate material covered with the microporous membrane material was subjected to a heat press treatment at a temperature of 100°C and a pressure of 3Mpa for 20 minutes using a flat hot press machine to modify the substrate material with an amino functional reagent, and at the same time, one end of the amino functional reagent was embedded in the microporous membrane layer to bond the formed substrate layer and the microporous membrane layer. After the heat press treatment, the fiber was washed with water until the pH value was neutral, and dried at 60°C to a constant weight to obtain a composite fiber membrane for removing hydrogen fluoride gas.

[0069] Comparative Example 1

[0070] A method for preparing modified fibers, which differs from Example 1 in that a microporous membrane layer is not covered on the substrate layer. The specific method comprises the following steps:

[0071] Step 1, swelling of the matrix material: select polyacrylonitrile fiber with an acrylonitrile monomer content greater than 80wt% as the matrix material, place the matrix material in a 40% diethylenetriamine aqueous solution, and soak it at room temperature for 12 hours to fully swell the matrix material. After removing excess solvent, a swollen matrix material is obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0072] Step 2, preparation of modified fiber: using a flat hot press machine to heat press the swollen base material at a temperature of 95°C and a pressure of 1Mpa for 60 minutes to modify the base material with an amino functional reagent to form a base layer. After the hot press treatment, the fiber is washed with water until the pH value is neutral, and dried at 60°C to constant weight to obtain modified fiber.

[0073] Comparative Example 2

[0074] A method for preparing modified fibers, which differs from Example 2 in that a microporous membrane layer is not covered on the substrate layer. The specific method comprises the following steps:

[0075] Step 1, swelling of the base material: amino polyacrylonitrile fiber with an acrylonitrile monomer content greater than 10wt% is selected as the base material, and the material is placed in a diethylenetriamine aqueous solution with a mass concentration of 20%, and soaked at 50°C for 3 hours to fully swell the base material, and after removing excess solvent, a swollen base material is obtained. The mass percentage of the solvent contained in the swollen base material is 10%.

[0076] Step 2, preparation of modified fiber: using a flat hot press machine to heat press the swollen base material at a temperature of 100°C and a pressure of 3Mpa for 20 minutes to modify the base material with an amino functional reagent to form a base layer. After the hot press treatment, the fiber is washed with water until the pH value is neutral, and dried at 60°C to constant weight to obtain modified fiber.

[0077] Comparative Example 3

[0078] A method for preparing a microporous membrane by heat pressing treatment, which differs from Example 1 in that no swelling base material is provided. The specific method comprises the following steps:

[0079] A polypropylene microporous membrane was selected and heat-pressed for 60 minutes at a temperature of 95°C and a pressure of 1 MPa using a flat hot press. After the heat-pressing treatment, the membrane was washed with water until the pH of the fiber was neutral, and dried at 60°C to constant weight to obtain a heat-pressed microporous membrane.

[0080] Comparative Example 4

[0081] A method for preparing a composite fiber membrane for removing hydrogen fluoride gas, which differs from Example 1 in that no amino functional reagent is added. The specific method comprises the following steps:

[0082] Step 1, swelling of the matrix material: amino polyacrylonitrile fiber with an acrylonitrile monomer content greater than 80wt% is selected as the matrix material, and the matrix material is placed in pure water and soaked at room temperature for 12 hours to fully swell the matrix material. After removing excess solvent, a swollen matrix material is obtained. The mass percentage of the solvent contained in the swollen matrix material is 10%.

[0083] Step 2, preparation of composite fiber membrane for removing hydrogen fluoride gas: covering the swollen base material with a layer of polypropylene microporous membrane. The pore size of the polypropylene microporous membrane material is 0.1 μm; the resistance of the microporous membrane material is less than 100 Pa when the air linear velocity is 5.33 cm / s.

[0084] The substrate material covered with the polypropylene microporous membrane was subjected to a heat press treatment at a temperature of 95°C and a pressure of 1 MPa for 60 minutes using a flat hot press. After the heat press treatment, the fiber was washed with water until the pH value of the fiber was neutral, and dried at 60°C to a constant weight to obtain a composite fiber membrane for removing hydrogen fluoride gas.

[0085] Sampling test: The composite fiber membranes prepared in Examples 1 to 3 were used as Sample 1, Sample 2 and Sample 3, respectively. The modified fibers prepared in Comparative Examples 1 and 2 were used as Samples 4 and 5. The hot-pressed microporous membrane prepared in Comparative Example 3 was used as Sample 6. The composite fiber membrane prepared in Comparative Example 4 was used as Sample 7.

[0086] The dried samples 1 to 7 were tested for hydrogen fluoride removal rate and anion exchange capacity.

[0087] The test method for hydrogen fluoride removal rate is as follows:

[0088] Accurately cut a single fiber disc with a diameter of 6.0 cm and a weight greater than 1 g from the dried samples 1 to 7, place the fiber disc in an adsorption column with an inner diameter of 5.2 cm, tighten and fix it, and use a dynamic adsorption experiment to characterize the hydrogen fluoride removal performance of the composite fiber membrane and its combination with the regeneration liquid. Figure 2 A certain concentration of hydrogen fluoride gas and fluorine-containing particles mixed with the gas in the adsorption column was passed through the composite fiber membrane material to conduct a hydrogen fluoride purification adsorption experiment, and the relevant experimental data were recorded.

[0089] The anion exchange capacity was determined as follows:

[0090] Experimental group: Before the test, 0.5 mol / L NaOH solution was used to soak and regenerate the dried samples 1 to 7 for 6 hours according to the liquid-solid ratio ≥ 100 / 1, and washed until neutral. After drying, 0.100 g of the sample and 50 mL of 0.1 mol / L hydrochloric acid solution were accurately weighed and added to a 100 mL conical flask and allowed to stand for 12 hours. Then, the filtrate was filtered to obtain the filtrate; 10 mL of the filtrate was transferred and titrated with standard sodium hydroxide solution.

[0091] At the same time, according to the above test method, no sample was added to serve as a blank control group.

[0092] The formula for calculating ion exchange capacity is: Q = (5 × (V 0 -V1 )×C NaOH ) / W; where Q is the anion exchange capacity of the sample, mmol / g; V 0 V is the volume of sodium hydroxide solution consumed by the blank control group, mL; 1 is the volume of sodium hydroxide solution consumed by the experimental group, mL; C NaOH is the concentration of the standard sodium hydroxide solution used for titration, mol / L; W is the weight of the sample, g.

[0093] The test results are shown in Table 1.

[0094] Table 1 Hydrogen fluoride removal rate and anion exchange capacity test results

[0095]

[0096]

[0097] Table 25. Material resistance test results and bonding firmness observation results at 33 cm / s

[0098]

[0099]

[0100] As can be seen from Table 1, the composite fiber membrane for removing hydrogen fluoride gas obtained by the preparation method of the embodiment of the present invention has excellent removal efficiency for hydrogen fluoride gas and hydrogen fluoride aerosol in the air, and the maximum removal efficiency can reach more than 99%. The composite fiber membrane prepared by the embodiment of the present invention exhibits the characteristics of high sensitivity and high removal rate.

[0101] In contrast, the amino polyacrylonitrile fiber alone and the microporous membrane alone in Comparative Examples 1 to 3 have poor removal effects on the mixture of hydrogen fluoride gas and hydrogen fluoride aerosol.

[0102] In comparative example 4, when no polyamine reagent is used, simple hot pressing treatment cannot make the base layer and the microporous membrane layer tightly bonded. However, when the polyamine reagent is used for bonding in the embodiment of the present invention, the base material is further modified, and the anion exchange capacity of the composite fiber membrane is increased without causing a significant increase in resistance, which further highlights the importance of using polyamine reagents to bond the base layer and the microporous membrane layer.

[0103] The following is a regeneration experiment on the composite fiber membranes prepared in Examples 1 to 3.

[0104] Example 4

[0105] A method for regenerating a composite fiber membrane for removing hydrogen fluoride gas comprises the following steps:

[0106] The composite fiber membranes prepared in Examples 1 to 3 were selected to adsorb hydrogen fluoride gas.

[0107] A sodium hydroxide solution with a mass concentration of 3% is used as the regeneration solution; the composite fiber membrane after adsorption penetration is sprayed with a sodium hydroxide solution with a mass concentration of 3%, and the spraying speed is to spray the composite fiber membrane with the same mass of regeneration solution per second, and the spraying time is 5 minutes. During regeneration, the ratio of the molar amount of alkali in the regeneration solution to the molar amount of anionic groups in the composite fiber membrane is 45:1.

[0108] The experimental conditions of the adsorption-regeneration process are as follows:

[0109] At room temperature and pressure, the carrier gas is nitrogen. Hydrogen fluoride gas 100mg / m 3 , fluorine-containing particles above 0.3 microns are greater than 100,000 pcs / L, use Figure 2 The device was used for the experiment, with a gas flow rate of 1L / min and each test lasting 20min.

[0110] The composite fiber membrane regenerated according to the regeneration method of Example 4 was subjected to the above-mentioned adsorption-regeneration process. After twenty repetitions, the removal rate of the composite fiber membrane for hydrogen fluoride gas and hydrogen fluoride aerosol did not decrease. Figure 3 This shows that the composite fiber membranes of Examples 1 to 3 of the present invention have excellent regeneration performance and can be reused many times.

[0111] Example 5

[0112] A method for regenerating a composite fiber membrane for removing hydrogen fluoride gas comprises the following steps:

[0113] The composite fiber membranes prepared in Examples 1 to 3 were selected to adsorb hydrogen fluoride gas.

[0114] A sodium hydroxide solution with a mass concentration of 3% is used as the regeneration solution; the composite fiber membrane after adsorption saturation is immersed in the sodium hydroxide solution with a mass concentration of 3% for regeneration, and the immersion time is 30s.

[0115] The experimental conditions of the adsorption-regeneration process are as follows:

[0116] At room temperature and pressure, the carrier gas is nitrogen. Hydrogen fluoride gas 100mg / m 3 , fluorine-containing particles above 0.3 microns are greater than 100,000 pcs / L, use Figure 2 The device was used for the experiment, with a gas flow rate of 1L / min and each test lasting 20min.

[0117] The composite fiber membrane regenerated according to the regeneration method of Example 5 repeated the above adsorption-regeneration process, and after repeating it twenty times, the removal rate of hydrogen fluoride gas and hydrogen fluoride aerosol by the composite fiber membrane did not decrease. This shows that the composite fiber membranes of Examples 1 to 3 of the present invention have excellent regeneration performance and can be reused many times.

[0118] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A composite fiber membrane for removing hydrogen fluoride gas, characterized in that: The composite fiber membrane comprises a substrate layer and a microporous membrane layer; The base layer is obtained by modifying the base material under hot pressing treatment using an amino functional agent dispersed inside the base material; at the same time, one end of the amino functional agent is embedded in the microporous membrane layer to make the base layer and the microporous membrane layer bonded; The matrix material is polyacrylonitrile fiber or amino polyacrylonitrile fiber; the content of acrylonitrile monomer in the matrix material is 10wt% to 99wt%; The amino functional agent is an amine compound containing at least two amino groups.

2. The composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized in that: The amino functional agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine and p-phenylenediamine; The microporous membrane material used in the microporous membrane layer is any one of polypropylene microporous membrane, polyester microporous membrane, polyamide microporous membrane, polytetrafluoroethylene microporous membrane and polytetrafluoroethylene microporous membrane; the pore size of the microporous membrane material is 0.1 μm to 1 μm.

3. The composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized in that: The ion exchange capacity of the composite fiber membrane is 1 mmol / g to 6 mmol / g; the resistance of the composite fiber membrane is less than 250 Pa when the air linear velocity is 5.33 cm / s.

4. A method for preparing a composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized in that: The following steps are involved: placing the base material in a solution containing an amino functional reagent to fully swell the base material to obtain a swollen base material; The microporous membrane material is covered on the swollen base material and subjected to heat pressing treatment to modify the base material with an amino functional agent. At the same time, one end of the amino functional agent is embedded in the microporous membrane layer to bond the formed base layer and the microporous membrane layer to obtain a composite fiber membrane for removing hydrogen fluoride gas.

5. The method for preparing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized in that: The amino functional agent is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine and p-phenylenediamine; The microporous membrane material used in the microporous membrane layer is any one of a polypropylene microporous membrane, a polyester microporous membrane, a polyamide microporous membrane, a polytetrafluoroethylene microporous membrane and a polytetrafluoroethylene microporous membrane; the pore size of the microporous membrane material is 0.1 μm to 1 μm; the resistance of the microporous membrane material at an air linear velocity of 5.33 cm / s is <200 Pa.

6. The method for preparing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized in that: The conditions of the hot pressing treatment are: The temperature is 60°C to 140°C, the time is 1min to 120min, and the pressure is 0MPa to 30MPa.

7. The method for preparing a composite fiber membrane for removing hydrogen fluoride gas according to claim 4, characterized in that: The solution containing the amino functional reagent is obtained by dissolving the amino functional reagent in a solvent; In the solution containing the amino functional reagent, the mass concentration of the amino functional reagent is 1% to 50%; The solvent is at least one of water, methanol, ethanol, propanol, butanol, ethylene glycol and propylene glycol; the mass percentage of the solvent contained in the swollen matrix material is 10% to 60%.

8. Use of the composite fiber membrane for removing hydrogen fluoride gas according to claim 1 as a fluoride ion adsorbing material for treating hydrogen fluoride gas.

9. Use of the composite fiber membrane for removing hydrogen fluoride gas according to claim 8 as a fluoride ion adsorbing material for treating hydrogen fluoride gas, characterized in that: The hydrogen fluoride gas contains hydrogen fluoride aerosol with a particle size of 0.3 μm to 1 μm.

10. A method for regenerating a composite fiber membrane for removing hydrogen fluoride gas according to claim 1, characterized in that: The following steps are involved: An inorganic alkaline solution with a mass concentration of 0.5% to 10% is used as the regeneration solution; Soaking the used composite fiber membrane in an inorganic alkali solution, or spraying the used composite fiber membrane with the inorganic alkali solution; The inorganic base in the inorganic base solution is any one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

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