Temperature-resistant molecular sieve paper-based gas separation material and preparation method thereof

Abstract

The present application relates to aramid fiber, molecular sieve, separation material preparation technical field, especially in kind of temperature resistant molecular sieve paper base gas separation material and preparation method thereof, the preparation method includes the following steps: step 1: raw material preparation and pretreatment;Step 2: after slurry preparation of raw materials and water, defibrillation is carried out, and mixed slurry suspension A is obtained;Step 3: mixed slurry suspension A is poured into the slurry storage room, and slurry suspension B containing aramid pulp fiber, molecular sieve is obtained;Step 4: homogenate slurry suspension B, and molecular sieve-aramid fiber wet paper web is obtained;Step 5: pressing and drying, and temperature resistant molecular sieve paper base gas separation material is obtained.The present application utilizes aramid pulp fiber as the skeleton structure of paper base material, has excellent heat resistance, flame retardant performance, can give the prepared paper base material stable work in high temperature, even hot gas, and widens the application range of paper base material.

Description

TECHNICAL FIELD

[0001] The application relates to aramid fiber, molecular sieve, and separation material preparation technology fields, in particular to a temperature-resistant molecular sieve paper-based gas separation material and a preparation method thereof. BACKGROUND

[0002] A large amount of pollutants discharged in industry, transportation and daily life will enter the air, gradually becoming an "invisible killer" that harms the respiratory tract, lungs and blood of human bodies. Long-term exposure to air pollution can cause cancer and damage the immune, nervous and respiratory systems. Air pollution is the fifth largest death risk factor in the world. The nature of air pollutants is very complex, including harmful gases, small droplets and solid particulate matters, all of which can seriously affect human health. Among them, the source of particulate pollutants (PMs) is very rich, and the most dangerous is the fine particulate matter with an air dynamic diameter less than 2.5 microns, which is called PM2.5. Because of its small size, it is extremely easy to enter the lungs through the respiratory tract, and long-term contact can cause chronic respiratory and cardiovascular diseases. Therefore, to reduce the emission of PMs into the air, the most suitable solution is to prepare a high-temperature-resistant air filtration material to remove PMs directly from high-temperature pollution sources, which is also one of the simple and low-cost methods to reduce the related risks.

[0003] At present, there are two typical air filtration materials, one is a porous material for size screening, including activated carbon, porous ceramic and the like; and the other is a fiber-based air filtration material. Because the slip effect of the fiber on the air can significantly reduce the resistance of the air flow, compared with the porous material, the fiber-based filtration material has higher porosity and lower pressure drop. The molecular sieve is a synthetic hydrated silico-aluminate with a molecular screening function. Due to the surface force generated on the solid surface by the molecular attraction, when the air or other fluid flows, some molecules in the fluid collide with the surface because of the irregular motion, and the molecular concentration is generated on the surface, so that the number of such molecules in the fluid is reduced, thereby achieving the purpose of separation and removal. And it has a strong adsorption and removal effect on moisture, acetylene and carbon dioxide. However, the current fiber-based air filtration material has high resistance, low dust holding capacity, relatively small air volume, and cannot filter PM2.5 fine particles or has poor filtering effect on harmful gases. Therefore, there is an urgent need for a separation paper with high dust holding capacity and capable of filtering toxic and harmful gases and fine particles. SUMMARY

[0004] In view of the fact that the emission of waste gas is usually under high-temperature conditions, and the fiber-based filtration material has higher porosity and lower pressure drop compared with other filtration materials, the application provides a temperature-resistant molecular sieve paper-based gas separation material and a preparation method thereof.

[0005] The application is realized by the following technical scheme:

[0006] A preparation method of a temperature-resistant molecular sieve paper-based gas separation material, comprising the following steps:

[0007] Step 1: raw material preparation and pretreatment;

[0008] Constant weight treatment of aramid fibrids;

[0009] The aramid pulp fiber is pretreated by using a DMAc / LiCl / H2O mixed solution, and then a aramid pulp fiber dispersion solution is configured;

[0010] A PEO dispersant solution is configured by using a dispersant PEO and deionized water;

[0011] Step 2: After the constant weight treatment of aramid fibrids, molecular sieve, aramid pulp fiber dispersion solution, PEO dispersant solution and water are slurried, defibration is performed to obtain a mixed slurry suspension A;

[0012] Step 3: The mixed slurry suspension A is poured into a slurry storage chamber to obtain a slurry suspension B containing aramid pulp fiber and molecular sieve;

[0013] Step 4: The slurry suspension B is uniformly slurried, and the molecular sieve-aramid pulp fiber is attached to the forming net under the first vacuum suction treatment; after the attachment is completed, the second vacuum suction is performed to obtain a molecular sieve-aramid fiber wet paper web;

[0014] Step 5: The molecular sieve-aramid fiber wet paper web is sequentially pressed and dried to obtain a temperature-resistant molecular sieve paper-based gas separation material.

[0015] Preferably, in step 1, the concentration of the PEO dispersant solution is 0.1-0.15 g / ml.

[0016] Preferably, in step 1, the ratio of DMAc, LiCl and H2O in the DMAc / LiCl / H2O mixed solution is 500 mL:1 g:5 mL; the addition sequence when used is LiCl, H2O and DMAc.

[0017] Preferably, in step 1, the constant weight treatment of aramid fibrids is that the thickness of the aramid fibrids is 4-7 microns, the length is 80-600 microns, the constant weight treatment temperature is 20-30 DEG C, the humidity is 60%-80%, and the time is 3-7 days.

[0018] Preferably, in step 2, the aramid fibrids are selected by using 13X molecular sieve (sodium X) in terms of absolute dry weight, the main component of which is Na2O·Al2O3·2.45SiO2·6.0H2O, the effective pore size is about 10 angstroms, and any molecule greater than 3.64 angstroms and less than 10 angstroms can be adsorbed.

[0019] Preferably, in step 2, the ratio of aramid fiber, molecular sieve, aramid pulp fiber, PEO dispersant solution and water is (1.125-1.130) g, (0.250-1.252) g, (1.882-1.886) g, (14-20) ml, (1.5-2.5) L.

[0020] Preferably, in step 3, before the mixed slurry suspension A is poured into the slurry storage chamber, water is poured into the slurry storage chamber (3.5-6.5) L; after pouring, the total mass-volume concentration of aramid fiber and molecular sieve in slurry suspension B is (0.592-0.776) g / L.

[0021] Preferably, in step 4, the homogenization frequency is 10-20 times, and the time is 8-15 s; the filter screen filter mesh of the forming net is 200-600 meshes, the second vacuum suction frequency is 5-10 times, and the vacuum degree of the first vacuum suction and the second vacuum suction is-0.092 to-0.098 MPa.

[0022] Preferably, in step 5, the pressure during pressing is 0.2-0.6 MPa, and the time is 6-10 min; the temperature during drying is 95-120 DEG C, the pressure is 0.4 MPa, and the time is 15-20 min.

[0023] A temperature-resistant molecular sieve paper-based gas separation material prepared by the preparation method of the temperature-resistant molecular sieve paper-based gas separation material.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The preparation method of the temperature-resistant molecular sieve paper-based gas separation material of the present application utilizes DMAc / LiCI / H2O system for pretreatment of the surface of aramid pulp fiber, and the use environment is neutral, the solubility is strong, the solubility range is wide, and the stability is good. The DMAc / LiCI solution system is an excellent solvent for aramid pulp, which promotes the opening of the hydrogen bond between the molecular chains of aramid pulp, which is beneficial to the adhesion of molecular sieve on the surface of the fiber and improves the retention rate of molecular sieve in the paper-based material. At the same time, aramid pulp fiber is used as the skeleton structure of the paper-based material, which has excellent heat resistance and flame retardance, can endow the prepared paper-based material with stable work in high temperature and even hot gas, and broaden the application range of the paper-based material, which can be used for flue gas and tail gas treatment, and can also be used for end adsorption and separation of VOCs combustion method, and expand the application scene.

[0026] Molecular sieve is a kind of crystalline microporous material with uniform intracrystalline pore channel, which is connected by silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron through shared oxygen atom to form framework structure, and has excellent ion exchange, catalysis and adsorption performance.Compared with the filtration and separation material based on pure paper base and physical and mechanical interception, the application has higher adsorption effect on PMs, and the force mainly comes from molecular sieve, which innovates the principle of paper base functional material.

[0027] The reagents used in the application are all conventional drug reagents, which are low-toxic, inexpensive and easy to obtain, and the equipment used is all conventional instrument equipment, which lays a good foundation for the engineering of high-temperature resistant molecular sieve paper base and improves the implementability of process engineering. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the average thickness and error column chart of the product obtained in examples 1-5;

[0029] Figure 2 It is the air permeability column chart of the product obtained in examples 1-5;

[0030] Figure 3 It is the evenness column chart of the product obtained in examples 1-5;

[0031] Figure 4 It is the PM2.5 filtration efficiency schematic diagram of the product obtained in examples 1-5;

[0032] Figure 5 It is the formaldehyde filtration efficiency schematic diagram of the product obtained in examples 1-5;

[0033] Figure 6 It is the SEM diagram of the molecular sieve attachment in the product obtained in example 5;

[0034] Figure 7 It is the XRD diagram of the product obtained in example 5. DETAILED DESCRIPTION

[0035] The application will be further described in detail below in combination with specific examples, which are an explanation but not a limitation of the application.

[0036] The application discloses a preparation method of a temperature-resistant molecular sieve paper base gas separation material.

[0037] Step 1: raw material preparation and pretreatment

[0038] The constant weight treatment of aramid fibrid is that the thickness of the aramid fibrid is 4-7 microns, the length is 80-600 microns, the constant weight treatment temperature is 20-30 DEG C, the humidity is 60%-80%, and the time is 3-7 days.

[0039] The aramid pulp fiber is pretreated on the surface by using DMAc / LiCl / H2O mixed solution, and then the aramid pulp fiber dispersion solution is configured; wherein the ratio of DMAc, LiCl and H2O in the DMAc / LiCl / H2O mixed solution is 500 mL:1 g:5 mL; the adding sequence in use is LiCl, H2O and DMAc.

[0040] A PEO dispersant solution with a concentration of 0.1-0.15 g / ml is configured by using a dispersant PEO and deionized water.

[0041] Step 2: The constant weight treated aramid fiber, molecular sieve, aramid pulp fiber dispersion solution, PEO dispersant solution and water are slurried, and then defibrated to obtain a mixed slurry suspension A. The aramid fiber is selected by absolute dry weight, and the 13X molecular sieve (sodium X) is selected, the main component of which is Na2O·Al2O3·2.45SiO2·6.0H2O, and the effective pore size is about 10A, which can adsorb any molecules larger than 3.64A and smaller than 10A. The ratio of aramid fiber, molecular sieve, aramid pulp fiber, PEO dispersant solution and water is (1.125-1.130) g, (0.250-1.252) g, (1.882-1.886) g, (14-20) ml, (1.5-2.5) L.

[0042] Step 3: The mixed slurry suspension A is poured into a slurry storage chamber to obtain a slurry suspension B containing aramid pulp fiber and molecular sieve. Before the mixed slurry suspension A is poured into the slurry storage chamber, water is added to the slurry storage chamber (3.5-6.5) L; after pouring, the total mass-volume concentration of aramid fiber and molecular sieve in the slurry suspension B is (0.592-0.776) g / L.

[0043] Step 4: The slurry suspension B is uniformly slurried for 10-20 times for 8-15 s, and the molecular sieve-aramid pulp fiber is attached to the forming wire with a mesh size of 200-600 under the first vacuum suction treatment; after the attachment is completed, the second vacuum suction is performed for 5-10 times to obtain a molecular sieve-aramid fiber wet paper web; wherein the vacuum degree of the first vacuum suction and the second vacuum suction is-0.092 to-0.098 MPa, and the motor power of the vacuum pump used is 2.2 KW.

[0044] Step 5: The molecular sieve-aramid fiber wet paper web is sequentially pressed and dried to obtain a temperature-resistant molecular sieve paper-based gas separation material. The pressure during pressing is 0.2-0.6 MPa, and the time is 6-10 min; the temperature during drying is 95-120℃, the pressure is 0.4 MPa, and the time is 15-20 min.

[0045] The application further discloses a preparation method of the temperature-resistant molecular sieve paper-based gas separation material.

[0046] Example 1

[0047] Step 1, raw material preparation and pretreatment:

[0048] Constant weight treatment: the aramid fibrid with a thickness of 4 microns and a length of 100 microns is placed in a constant temperature and humidity box, the temperature is set to 20 DEG C, the humidity is set to 60%, and the aramid fibrid is placed for 7 days.

[0049] A PEO dispersant solution with a concentration of 0.1 g / ml is prepared by using 1.5 g of PEO and 150 ml of deionized water.

[0050] 5 g of LiCl, 1 L of DMAc and 5 mL of deionized water are weighed to prepare a swelling liquid for pretreating aramid pulp fibers; then the pretreated pulp fibers are subjected to a beating treatment under the conditions of a power of 2.2 KW and a spindle speed of 900-1000 r / min for 15 min.

[0051] Step 2, 1.885 g of the pretreated aramid pulp fibers, 1.129 g of the constant weight treated aramid fibrid, 0.251 g of the molecular sieve, 16 ml of the PEO dispersant solution and 2.0 L of tap water are added into a standard fiber defibrator to prepare a slurry, the slurry is defibrated for 20000 revolutions, and the defibration time is 4 min, so that a mixed slurry suspension A with a concentration of 1.632 g / L is obtained.

[0052] Step 3, 3.5 L of water is first added into a slurry storage chamber of a paper sheet former with a cross-sectional area of 0.0314 m2, then the mixed slurry suspension A of step 3 is poured into the slurry storage chamber, so that a slurry with a concentration of 0.594 g / L is formed, that is, the total mass-volume concentration of the aramid pulp fibers, the aramid fibrid and the molecular sieve is 0.594 g / L, and a diluted slurry suspension B is obtained.

[0053] Step 4, the diluted slurry suspension B in the slurry storage chamber is uniformly grinded by a uniform gridding roller for 10 times with a gridding time of 8 s; the diluted slurry suspension B is dehydrated and formed under the action of vacuum suction through a forming net with a diameter of 200 mm and a mesh number of 200, after the filtration of the slurry is completed, the vacuum suction is further performed for 5 s, and a molecular sieve-aramid fiber wet paper web is obtained.

[0054] Step 5, the formed molecular sieve-aramid fiber wet paper web is placed into a paper sheet press after being padded with wool felt on both sides, and is pressed for 6 min under a pressure of 0.2 MPa; then the molecular sieve-aramid fiber wet paper web is placed into a paper sheet dryer, and is dried under the conditions of a temperature of 95 DEG C and a pressure of 0.4 MPa for 20 min, so that a high-temperature-resistant molecular sieve aramid fiber paper is obtained.

[0055] The actual weight of the molecular sieve aramid fiber paper prepared in Example 1 is 2.20 g, the air permeability is 41.868 (μm / Pa·s), the average thickness is 0.340 mm, the uniformity index is 29, the filtration efficiency for formaldehyde is 75.28%, and the filtration efficiency for PM2.5 is 95.15%.

[0056] Example 2

[0057] Step 1, preparation of raw materials and pretreatment:

[0058] Constant weight treatment: aramid fibers with a thickness of 4 microns and a length of 100 microns are placed in a constant temperature and humidity box, the temperature is set to 20℃ and the humidity is set to 60%, and the fibers are placed for 7 days; 1.5 g of PEO and 150 ml of deionized water are used to prepare a PEO dispersant solution with a concentration of 0.1 g / ml.

[0059] 5 g of LiCl, 1 L of DMAc, and 5 mL of deionized water are weighed to prepare a swelling solution for pretreating aramid pulp fibers; then the pretreated pulp fibers are subjected to a beating treatment at a power of 2.2 KW and a main shaft speed of 900-1000 r / min for 15 min.

[0060] Step 2, 1.634 g of pretreated aramid pulp fibers, 1.129 g of constant weight treated aramid fibers, 0.523 g of molecular sieve, 16 ml of PEO dispersant solution, and 2.0 L of tap water are added to a standard fiber defibrator to prepare a slurry, and the slurry is defibrated for 20000 revolutions and 4 min to obtain a mixed slurry suspension A with a concentration of 1.643 g / L.

[0061] Step 3, 3.5 L of water is first added to the slurry storage chamber of a paper former with a cross-sectional area of 0.0314 m2, and then the mixed slurry suspension A of step 3 is poured into the slurry storage chamber to form a slurry with a concentration of 0.597 g / L, i.e., the total mass-volume concentration of aramid pulp fibers, aramid fibers, and molecular sieve is 0.597 g / L, to obtain a diluted slurry suspension B.

[0062] Step 4, the diluted slurry suspension B in the slurry storage chamber is uniformly dispersed by a uniform slurry roller for 10 times and 8 s; the diluted slurry suspension B is dehydrated and formed by a forming wire with a diameter of 200 mm and a mesh of 200 under the action of vacuum suction, and after the slurry filtration is completed, vacuum suction is performed for another 5 s to obtain a molecular sieve-aramid fiber wet paper web.

[0063] Step 5, the formed molecular sieve-aramid fiber wet paper web is placed in a paper press with wool felt on both sides under a pressure of 0.2 MPa for 6 min, and then placed in a paper dryer at a temperature of 95℃ and a pressure of 0.4 MPa for 20 min to obtain a high-temperature-resistant molecular sieve aramid fiber paper.

[0064] The actual weight of the molecular sieve aramid fiber paper prepared in Example 2 was 2.02 g, the air permeability was 37.353 (μm / Pa-s), the average thickness was 0.314 mm, the uniformity index was 17, the filtration efficiency for formaldehyde was 79.28%, and the filtration efficiency for PM2.5 was 97.21%.

[0065] Example 3

[0066] Step 1, raw material preparation and pretreatment:

[0067] Constant weight treatment: aramid fibers with a thickness of 4 microns and a length of 100 microns were placed in a constant temperature and humidity box, the temperature was set to 20°C and the humidity was set to 60%, and the aramid fibers were placed for 7 days; 1.5 g of PEO and 150 ml of deionized water were used to prepare a PEO dispersant solution with a concentration of 0.1 g / ml.

[0068] 5 g of LiCl, 1 L of DMAc, and 5 mL of deionized water were weighed to prepare a swelling solution for pretreating aramid pulp fibers; then the pretreated pulp fibers were subjected to a refining treatment at a power of 2.2 KW and a main shaft speed of 900-1000 r / min for 15 min.

[0069] Step 2, 1.382 g of pretreated aramid pulp fibers, 1.129 g of constant weight treated aramid fibers, 0.754 g of molecular sieve, 16 ml of PEO dispersant solution, and 2.0 L of tap water were added to a standard fiber defibrator to prepare a slurry, and the slurry was defibrated for 20000 revolutions and 4 min to obtain a mixed slurry suspension A with a concentration of 1.633 g / L.

[0070] Step 3, 3.5 L of water was first added to the slurry storage chamber of a paper sheet former with a cross-sectional area of 0.0314 m2, and then the mixed slurry suspension A of step 3 was poured into the slurry storage chamber to form a slurry with a concentration of 0.594 g / L, i.e., the total mass-volume concentration of aramid pulp fibers, aramid fibers, and molecular sieve was 0.594 g / L, to obtain a diluted slurry suspension B.

[0071] Step 4, the diluted slurry suspension B in the slurry storage chamber was uniformly dispersed by a uniform dispersion roller for 10 times and 8 s; the diluted slurry suspension B was dewatered and formed by a forming wire with a diameter of 200 mm and a mesh of 200 under the action of vacuum suction, and after the slurry filtration was completed, the vacuum suction was continued for 5 s to obtain a molecular sieve-aramid fiber wet paper web.

[0072] Step 5, after the forming of the molecular sieve-aramid fiber wet paper, the two sides of the paper are padded with wool felt, and then the paper is put into a paper press, and the paper is pressed for 6 min under a pressure of 0.2 MPa. Then the paper is placed in a paper dryer, and dried at a temperature of 95 ℃ and a pressure of 0.4 MPa for 20 min, to obtain a high-temperature-resistant molecular sieve aramid fiber paper.

[0073] The actual weight of the molecular sieve aramid fiber paper prepared in Example 3 is 1.75 g, the air permeability is 30.850 (μm / Pa·s), the average thickness is 0.286 mm, the uniformity index is 29, the filtration efficiency for formaldehyde is 92.48%, and the filtration efficiency for PM2.5 is 97.43%.

[0074] Example 4

[0075] Step 1, preparation and pretreatment of raw materials:

[0076] Constant weight treatment: aramid fibrids with a thickness of 4 microns and a length of 100 microns are placed in a constant temperature and humidity box, and the temperature is set to 20 ℃ and the humidity is set to 60%, and the aramid fibrids are placed for 7 days; 1.5 g of PEO and 150 ml of deionized water are used to prepare a PEO dispersant solution with a concentration of 0.1 g / ml.

[0077] 5 g of LiCl, 1 L of DMAc, and 5 mL of deionized water are weighed to prepare a swelling solution for pretreating aramid pulp fibers; then the pretreated pulp fibers are subjected to beating treatment under the conditions of a power of 2.2 KW and a main shaft speed of 900-1000 r / min for 15 min.

[0078] Step 2, 1.131 g of pretreated aramid pulp fibers, 1.129 g of constant weight treated aramid fibrids, 1.005 g of molecular sieve, 16 ml of PEO dispersant solution, and 2.0 L of tap water are added to a standard fiber defibrator for slurry preparation, and the slurry is defibrated for 20,000 revolutions for 4 min to obtain a mixed slurry suspension A with a concentration of 1.633 g / L.

[0079] Step 3, 3.5 L of water is first added to the slurry storage chamber of a paper former with a cross-sectional area of 0.0314 m2, and then the mixed slurry suspension A of step 3 is poured into the slurry storage chamber to form a slurry with a concentration of 0.594 g / L, i.e., the total mass-volume concentration of aramid pulp fibers, aramid fibrids, and molecular sieve is 0.594 g / L, to obtain a diluted slurry suspension B.

[0080] Step 4, the diluted slurry suspension B in the slurry storage chamber is uniformly dispersed by a uniform slurry roller for 10 times and for 8 s; the diluted slurry suspension B is dehydrated and formed by a forming wire with a diameter of 200 mm and a mesh of 200 under the action of vacuum suction, and after the filtration of the slurry is completed, vacuum suction is performed for another 5 s to obtain a molecular sieve-aramid fiber wet paper.

[0081] Step 5, after the forming of the molecular sieve-aramid fiber wet paper web, the two sides are padded with wool felt, and then put into a paper press, and pressed for 6 min under a pressure of 0.2 MPa. Then, placed in a paper dryer, dried for 20 min at a temperature of 95 ℃ and a pressure of 0.4 MPa, to obtain a high-temperature-resistant molecular sieve aramid fiber paper.

[0082] The actual weight of the molecular sieve aramid fiber paper prepared in Example 4 is 1.64 g, the air permeability is 19.792 (μm / Pa·s), the average thickness is 0.251 mm, the uniformity index is 48, the filtration efficiency for formaldehyde is 83.84%, and the filtration efficiency for PM2.5 is 97.12%.

[0083] Example 5

[0084] Step 1, preparation and pretreatment of raw materials:

[0085] Constant weight treatment: aramid fibrids with a thickness of 4 microns and a length of 100 microns are placed in a constant temperature and humidity box, and the temperature is set to 20 ℃ and the humidity is set to 60%, and placed for 7 days; 1.5 g of PEO and 150 ml of deionized water are used to prepare a PEO dispersant solution with a concentration of 0.1 g / ml.

[0086] 5 g of LiCl, 1 L of DMAc, and 5 mL of deionized water are weighed to prepare a swelling solution for pretreatment of aramid pulp fibers; then the treated pulp fibers are subjected to grinding treatment under the conditions of a power of 2.2 KW and a main shaft speed of 900-1000 r / min for 15 min.

[0087] Step 2, 0.880 g of pretreated aramid pulp fibers, 1.129 g of constant weight treated aramid fibrids, 1.257 g of molecular sieve, 16 ml of PEO dispersant solution, and 2.0 L of tap water are added to a standard fiber defibrator for slurry preparation, defibrated for 20000 revolutions, and the defibration time is 4 min, to obtain a mixed slurry suspension A with a concentration of 1.633 g / L.

[0088] Step 3, 3.5 L of water is first added to the slurry storage chamber of a paper former with a cross-sectional area of 0.0314 m2, and then the mixed slurry suspension A of step 3 is poured into the slurry storage chamber to form a slurry with a concentration of 0.594 g / L, i.e. the total mass-volume concentration of aramid pulp fibers, aramid fibrids, and molecular sieve is 0.594 g / L, to obtain a diluted slurry suspension B.

[0089] Step 4, the dilute pulp suspension B in the stock chest is homogenized by a homogenizer for 10 times, and the homogenizing time is 8s; the dilute pulp suspension B is dewatered and formed by a forming wire with a diameter of 200mm and a mesh of 200 under the action of vacuum suction, and after the pulp filtration is completed, the vacuum suction is continued for 5s, to obtain the molecular sieve-aramid fiber wet paper web.

[0090] Step 5, the formed molecular sieve-aramid fiber wet paper web is placed on the paper press machine with wool felt on both sides under the pressure of 0.2Mpa for 6min. Then it is placed in the paper dryer at a temperature of 95℃ and a pressure of 0.4MPa for 20min, to obtain the high-temperature-resistant molecular sieve aramid fiber paper.

[0091] The actual weight of the molecular sieve aramid fiber paper prepared in Example 5 is 1.47g, the air permeability is 20.320(μm / Pa·s), the average thickness is 0.215mm, the uniformity index is 38, the filtration efficiency for formaldehyde is 75.08%, and the filtration efficiency for PM2.5 is 91.15%. Figure 6 It can be seen that a large amount of molecular sieve is attached around the aramid fiber, which indicates that the molecular sieve in the present application is well dispersed in the aramid fiber.

[0092] Reference Figure 7 It can be more clearly seen that there are three sharp strong peaks in the range of 2θ = 25~35°, which are the characteristic peaks of molecular sieve, indicating that the paper base is combined with 13X type molecular sieve with high crystallinity and relatively complete; the wide peak near 2θ = 20~22.5° is the characteristic peak of aramid fiber, indicating that the molecular sieve is distributed in the paper base material.

[0093] The products prepared in Examples 1~5 are tested, the sample is a TD10-200 type paper former for paper forming, and the paper size is 200. The air permeability is tested by using a Glier air permeability tester, and the air permeability = 1.27V / t(μm / Pa·s) according to the calculation formula. The filtration efficiency is simulated by using the fine particulate matter generated during cigarette combustion in the environment with different particle sizes of PMs. The filtration efficiency calculation formula is: filtration efficiency = (initial pollutant concentration-average pollutant concentration after adding the filter paper base for a period of time) / initial pollutant concentration*100%. Table 1 is the quantitative, component ratio and test results of Examples 1~5.

[0094] Table 1 quantitative, component ratio and test results of Examples

[0095]

[0096] Reference Figure 5 It can be seen that when the content of molecular sieve is 30%, the filtration performance for PM2.5 solid pollutant particles is the best. Reference Figure 6It can be seen that the adsorption and filtration performance of toxic gas formaldehyde is best when the molecular sieve content is 30%.

[0097] The above merely describes the preferred embodiments of the present application, and is not intended to limit the technical solutions of the present application in any way. Those skilled in the art should understand that, without departing from the spirit and principle of the present application, the technical solutions can also be modified and replaced in several simple ways, and these modifications and replacements also all belong to the protection scope covered by the claims.

Claims

1. A method for preparing a temperature-resistant molecular sieve paper-based gas separation material, characterized in that, The method comprises the following steps: Step 1: raw material preparation and pretreatment; Constant weight treatment of aramid fibrids; the process is as follows: the thickness of aramid fibrids is 4-7 microns, the length is 80-600 microns, the constant weight treatment temperature is 20-30 DEG C, the humidity is 60%-80%, and the time is 3-7 days; Surface pretreatment of aramid pulp fibers by using DMAc / LiCl / H2O mixed solution, and then configuration of aramid pulp fiber dispersion solution; the ratio of DMAc, LiCl and H2O in the DMAc / LiCl / H2O mixed solution is 500 mL:1 g:5 mL; the adding sequence in use is LiCl, H2O and DMAc; PEO dispersant solution is configured by using dispersant PEO and deionized water; Step 2: after the constant weight treatment of aramid fibrids, molecular sieve, aramid pulp fiber dispersion solution, PEO dispersant solution and water are mixed to perform defibration, and mixed pulp suspension A is obtained; the aramid fibrids are calculated by absolute dry weight, 13X molecular sieve is selected, the composition of which is Na2O·Al2O3·2.45SiO2·6.0H2O, the effective pore size is 10 angstroms, and any molecule with a size greater than 3.64 angstroms and less than 10 angstroms can be adsorbed; The mixing ratio of aramid fibrids, molecular sieve, aramid pulp fiber dispersion solution, PEO dispersant solution and water is (1.125-1.130) g, (0.250-1.252) g, (1.882-1.886) g, (14-20) ml, (1.5-2.5) L; Step 3: the mixed pulp suspension A is poured into a pulp storage chamber to obtain pulp suspension B containing aramid pulp fibers and molecular sieve; Step 4: the pulp suspension B is uniformly mixed, and the molecular sieve-aramid pulp fibers are attached to the forming net under the first vacuum suction treatment; After the attachment is completed, the second vacuum suction is performed to obtain the molecular sieve-aramid fiber wet paper web; the uniform mixing time is 8-15 s; the filter screen of the forming net has a mesh size of 200-600 meshes; the second vacuum suction is performed 5-10 times; the vacuum degree of the first and second vacuum suction is-0.092 to-0.098 MPa; Step 5: the molecular sieve-aramid fiber wet paper web is sequentially pressed and dried to obtain the temperature-resistant molecular sieve paper-based gas separation material; The pressure during the pressing is 0.2-0.6 MPa, and the time is 6-10 min; the temperature during the drying is 95-120 DEG C, the pressure is 0.4 MPa, and the time is 15-20 min.

2. The method for preparing the heat-resistant molecular sieve paper-based gas separation material according to claim 1, characterized in that, In step 1, the concentration of the PEO dispersant solution is 0.1-0.15 g / ml.

3. The method for preparing the heat-resistant molecular sieve paper-based gas separation material according to claim 1, characterized in that, In step 3, before the mixed pulp suspension A is poured into the pulp storage chamber, water is added to the pulp storage chamber (3.5-6.5) L; after the pouring, the total mass-volume concentration of aramid fibrids and molecular sieve in the pulp suspension B is (0.592-0.776) g / L.

4. A temperature-resistant molecular sieve paper-based gas separation material prepared by the method of any one of claims 1-3.

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