Preparation method and application of bismuth ion filter membrane

Abstract

The invention discloses a preparation method and application of a bismuth ion filter membrane, and the preparation method comprises the following steps: putting a filter membrane base material into a cleaner, adding a nonionic chelating agent solution and water, treating for 1-2 hours, and dehydrating after the treatment to obtain a filter membrane base material A; adding the filter membrane base material A and the chelated bismuth ion solution into a reaction kettle, then adding a nonionic chelating agent solution, and carrying out a reaction to obtain a bismuth ion inlaid filter membrane base material after the reaction is completed; and dehydrating and drying the bismuth ion embedded filter membrane base material to obtain the bismuth ion filter membrane.

Description

Preparation method and application of bismuth ion filter membrane Technical Field

[0001] The invention belongs to the technical field of filter membrane preparation, and particularly relates to a preparation method of a bismuth ion filter membrane and application thereof. Background Art

[0002] Due to the recent heightened pandemic, we've been using various ion-based antibacterial materials in masks and air filters. In addition to the traditional silver ion technology, we've also explored materials like platinum and gold. Our experience has shown that platinum ions offer superior and more stable antibacterial properties compared to silver ions, and they also produce more negative oxygen ions in the mask, arguably offering advantages over silver ions. Unfortunately, the cost is higher, with the materials costing ten times more than silver, making the price-performance ratio unacceptable. Furthermore, the use of gold ions further increases the price.

[0003] In applications, we've found that bismuth ions can enhance the effects of other metal ions, particularly in disinfectant materials, as seen in the recent COVID-19 pandemic. Bismuth plays a crucial role, not only enhancing the ions' ability to kill bacteria and eliminate viruses but also reducing costs and improving performance. This is an additive benefit. For example, we're well aware that silver ions can kill bacteria and disinfect, but they're expensive. Platinum ions are also more effective, but they're more expensive than silver. Given these unsuitable cost-effectiveness, we've added bismuth ions, significantly enhancing the performance of silver and platinum materials, thus lowering the cost of using precious metals. In experiments, we've shown that the cost of precious metals can be reduced by 5-10 times for the same level of bactericidal activity. Furthermore, bismuth ions have a photocatalytic effect, providing additional bactericidal capabilities. Bismuth, under photocatalysis, enhances its micro-EMC reaction, enabling sterilization at distances of 1-3 feet. This represents a significant added value and enhances the material's practical functionality.

[0004] It's understood that the most effective positive and negative electrode air purifiers on the market produce around 10,000 negative oxygen ions. This is generated by electrical stimulation, which can potentially produce excessive levels of ozone and hydroxyl radicals. Of course, the negative oxygen ion levels produced by standard air purifiers range from 2,000 to 6,000. However, bismuth ion filters can produce over 3 million negative oxygen ions without electrical stimulation, making them a very economical and environmentally friendly material.

[0005] Summary of the Invention

[0006] In view of the deficiencies of the prior art, the present invention provides a preparation method of a bismuth ion filter membrane and its application.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0009] (1) Pretreatment of the filter membrane substrate: Place the filter membrane substrate in a cleaning machine, add a nonionic chelating agent solution and water, soak and stir, and dehydrate after the treatment to obtain a filter membrane substrate A;

[0010] (2) Embedding of bismuth ions: The filter membrane substrate A obtained in step (1) and the chelated bismuth ion solution are added to a reactor, and then a non-ionic chelating agent solution is added to react. After the reaction is completed, a filter membrane substrate embedded with bismuth ions is obtained;

[0011] (3) Post-treatment: Dehydrating and drying the filter membrane substrate embedded with bismuth ions obtained in step (2) to obtain a bismuth ion filter membrane.

[0012] Preferably, in step (1), the filter membrane substrate is non-woven fabric, the non-ionic chelating agent is ammonium EDTA, and the concentration of the non-ionic chelating agent solution is 1 mol / L.

[0013] Preferably, the soaking and stirring treatment time in step (1) is 1-2 hours.

[0014] Preferably, in step (1), the mass ratio of the filter membrane substrate to water is 4-8:50, and the mass ratio of the nonionic chelating agent solution to water is 1:100-1000.

[0015] Preferably, the method for preparing the chelated bismuth ion solution in step (2) comprises the following steps:

[0016] S1, adding flake graphite to H2O2 / H2SO4 solution, stirring at room temperature for 10 minutes, then filtering, washing, and calcining at 500-600°C for 10-20 minutes in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol aqueous solution with a volume ratio of 1:1, ultrasonically treating under stirring for 8-12 hours, and obtaining flaky graphite after vacuum drying;

[0017] S2, adding 50 parts by weight of the flake graphite in step S1 to 920 parts by weight of deionized water, then adding 10 parts by weight of chitosan, adjusting the pH to 2-3, stirring and reacting at 40-50° C. for 4-6 hours, adding 20 parts by weight of chelated bismuth after the reaction is completed, and reacting at 60-70° C. for 3-4 hours, to obtain the chelated bismuth ion solution after the reaction is completed.

[0018] Preferably, the nonionic chelating agent in step (2) is ammonium EDTA, and the concentration of the nonionic chelating agent solution is 1 mol / L; the mass ratio of the filter membrane substrate A to the chelated bismuth ion solution is 4-8:50, and the mass ratio of the nonionic chelating agent solution to the chelated bismuth ion solution is 1:100-1000.

[0019] Preferably, in step (2), the reaction temperature is 30-40° C., the reaction time is 10-30 min, the reaction pressure is 0.1-0.15 MPa, and the pH is 6-7.

[0020] Preferably, the drying temperature in step (3) is 60-90° C. and the drying time is 4-8 hours.

[0021] The present invention also protects the bismuth ion filter membrane prepared by the preparation method.

[0022] The present invention also protects the application of the bismuth ion filter membrane in masks and air filter membranes.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention proposes for the first time the application of bismuth ions to masks and air filters. The masks and filters made of bismuth ions can produce more than 3 million negative oxygen ions in the test results. The specific value depends on the bismuth ion concentration used during production.

[0025] (2) The bismuth ion filter membrane prepared by the present invention is obtained by oxidizing, acidifying and ultrasonically treating flake graphite to obtain graphite with a good layered crystal structure, and the oxygen-containing functional groups on the graphite surface are increased, which is conducive to the subsequent reaction. The flake graphite is then reacted with chitosan to load chitosan on the graphite surface. Since chitosan contains a large number of active groups such as amino and carboxyl groups, it can react with the oxidized graphite, thereby increasing the bonding strength between chitosan and graphite. At the same time, chitosan has good adsorption properties. On the one hand, it can increase the subsequent bismuth ion loading amount and increase the bismuth ion content in the graphite. On the other hand, it can increase the bonding force between the graphite and the filter membrane material base, making the bismuth ion-containing graphite not easy to fall off, so that the prepared filter membrane has long-lasting antibacterial properties.

[0026] (3) The bismuth ion filter membrane prepared by the present invention introduces bismuth ions into flake graphite through a chemical reaction, and then introduces flake graphite into the filter membrane substrate. Through the photocatalytic effect of bismuth ions, a sterilization effect within a distance of 1-3 feet can be exerted. At the same time, due to the structure of bismuth ions, the negative oxygen ions generated by air filtration can also be increased. Using bismuth ions to make filter membranes and masks can obtain the most cost-effective material, which is ten times cheaper than silver ions and is economical and affordable. DETAILED DESCRIPTION

[0027] The following will be used to clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] All raw materials in the examples of the present invention can be obtained commercially. Among them, the non-ionic chelating agent (ammonium EDTA) and chelated bismuth can be purchased from Asia Sky Group. The concentration of bismuth ions in the chelated bismuth is 5%.

[0029] Example 1

[0030] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0031] (1) Pretreatment of the filter membrane substrate: 4 kg of non-woven fabric was placed in a cleaning machine, 50 kg of water and 500 mL of 1 mol / L diammonium EDTA were added, and the mixture was immersed and stirred for 1 h. After the treatment, the membrane substrate was dehydrated to obtain the filter membrane substrate A.

[0032] (2) Embedding of bismuth ions: The filter membrane substrate A (4 kg) obtained in step (1) and 50 kg of chelated bismuth ion solution were added to a reactor, and then 500 g of 1 mol / L ammonium EDTA was added. The pH was adjusted to 6, the reaction pressure was 0.1 MPa, and the reaction was carried out at 30° C. for 10 min. After the reaction was completed, a filter membrane substrate embedded with bismuth ions was obtained.

[0033] (3) Post-treatment: The bismuth ion-embedded filter membrane substrate obtained in step (2) was dehydrated and then dried at 70° C. for 6 h to obtain a bismuth ion filter membrane.

[0034] The method for preparing the chelated bismuth ion solution comprises the following steps:

[0035] S1, adding flake graphite to H2O2 / H2SO4 solution (H2O2 / H2SO4 volume ratio of 1:3, mass concentration of H2O2 of 30%, concentration of H2SO4 of 98%), stirring at room temperature for 10 min, then filtering, washing, and calcining at 500°C for 20 min in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol-water solution with a volume ratio of 1:1, ultrasonically treating under stirring for 10 h, and obtaining flaky graphite after vacuum drying;

[0036] S2, adding 50g of flake graphite in step S1 to 920g of deionized water, then adding 10g of chitosan, adjusting the pH to 2.5, stirring and reacting at 45°C for 5h, adding 20g of chelated bismuth after the reaction is completed, reacting at 65°C for 3.5h, and obtaining the chelated bismuth ion solution after the reaction is completed.

[0037] Example 2

[0038] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0039] (1) Pretreatment of the filter membrane substrate: 5 kg of non-woven fabric was placed in a cleaning machine, 50 kg of water and 500 mL of 1 mol / L diammonium EDTA were added, and the mixture was immersed and stirred for 1.5 h. After the treatment, the membrane substrate was dehydrated to obtain the filter membrane substrate A.

[0040] (2) Embedding of bismuth ions: The filter membrane substrate A (5 kg) obtained in step (1) and 50 kg of chelated bismuth ion solution were added to a reaction kettle, and then 500 g of 1 mol / L ammonium EDTA was added. The pH was adjusted to 6.5, the reaction pressure was 0.1 MPa, and the reaction was carried out at 40° C. for 10 min. After the reaction was completed, a filter membrane substrate embedded with bismuth ions was obtained.

[0041] (3) Post-treatment: The bismuth ion-embedded filter membrane substrate obtained in step (2) is dehydrated and then dried at 80° C. for 6 h to obtain a bismuth ion filter membrane.

[0042] The method for preparing the chelated bismuth ion solution comprises the following steps:

[0043] S1, adding flake graphite to H2O2 / H2SO4 solution (H2O2 / H2SO4 volume ratio of 1:3, mass concentration of H2O2 of 30%, concentration of H2SO4 of 98%), stirring at room temperature for 10 min, then filtering, washing, and calcining at 550 ° C for 15 min in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol aqueous solution with a volume ratio of 1:1, ultrasonically treating for 10 h under stirring conditions, and obtaining flaky graphite after vacuum drying;

[0044] S2, adding 50g of flake graphite in step S1 to 920g of deionized water, then adding 10g of chitosan, adjusting the pH to 2.5, stirring and reacting at 45°C for 5h, adding 20g of chelated bismuth after the reaction is completed, reacting at 65°C for 3.5h, and obtaining the chelated bismuth ion solution after the reaction is completed.

[0045] Example 3

[0046] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0047] (1) Pretreatment of the filter membrane substrate: 6 kg of non-woven fabric was placed in a cleaning machine, 50 kg of water and 500 mL of 1 mol / L diammonium EDTA were added, and the mixture was immersed and stirred for 1 h. After the treatment, the membrane substrate was dehydrated to obtain the filter membrane substrate A.

[0048] (2) Embedding of bismuth ions: The filter membrane substrate A (6 kg) obtained in step (1) and 50 kg of chelated bismuth ion solution were added to a reaction kettle, and then 500 g of 1 mol / L ammonium EDTA was added. The pH was adjusted to 7, the reaction pressure was 0.15 MPa, and the reaction was carried out at 40° C. for 20 min. After the reaction was completed, a filter membrane substrate embedded with bismuth ions was obtained.

[0049] (3) Post-treatment: The bismuth ion-embedded filter membrane substrate obtained in step (2) was dehydrated and then dried at 60° C. for 7 h to obtain a bismuth ion filter membrane.

[0050] The method for preparing the chelated bismuth ion solution comprises the following steps:

[0051] S1, adding flake graphite to H2O2 / H2SO4 solution (H2O2 / H2SO4 volume ratio of 1:3, mass concentration of H2O2 of 30%, concentration of H2SO4 of 98%), stirring at room temperature for 10 min, then filtering, washing, and calcining at 550°C for 20 min in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol aqueous solution with a volume ratio of 1:1, ultrasonically treating for 8 h under stirring conditions, and obtaining flaky graphite after vacuum drying;

[0052] S2, adding 50g of flake graphite in step S1 to 920g of deionized water, then adding 10g of chitosan, adjusting the pH to 2, stirring and reacting at 40°C for 6h, adding 20g of chelated bismuth after the reaction is completed, and reacting at 60°C for 4h, to obtain the chelated bismuth ion solution after the reaction is completed.

[0053] Example 4

[0054] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0055] (1) Pretreatment of the filter membrane substrate: 8 kg of non-woven fabric was placed in a cleaning machine, 50 kg of water and 500 mL of 1 mol / L diammonium EDTA were added, and the mixture was immersed and stirred for 2 h. After the treatment, the membrane substrate was dehydrated to obtain the filter membrane substrate A.

[0056] (2) Embedding of bismuth ions: The filter membrane substrate A (8 kg) obtained in step (1) and 50 kg of chelated bismuth ion solution were added to a reactor, and then 500 g of 1 mol / L diammonium EDTA was added. The pH was adjusted to 7, the reaction pressure was 0.15 MPa, and the reaction was carried out at 40° C. for 30 min. After the reaction was completed, a filter membrane substrate embedded with bismuth ions was obtained.

[0057] (3) Post-treatment: The bismuth ion-embedded filter membrane substrate obtained in step (2) was dehydrated and then dried at 90° C. for 6 h to obtain a bismuth ion filter membrane.

[0058] The method for preparing the chelated bismuth ion solution comprises the following steps:

[0059] S1, adding flake graphite to H2O2 / H2SO4 solution (H2O2 / H2SO4 volume ratio of 1:3, mass concentration of H2O2 of 30%, concentration of H2SO4 of 98%), stirring at room temperature for 10 min, then filtering, washing, and calcining at 600 ° C for 10 min in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol aqueous solution with a volume ratio of 1:1, ultrasonically treating under stirring for 12 h, and obtaining flaky graphite after vacuum drying;

[0060] S2, adding 50 parts by weight of the flake graphite in step S1 to 920 parts by weight of deionized water, then adding 10 parts by weight of chitosan, adjusting the pH to 3, stirring and reacting at 50°C for 4 hours, adding 20g of chelated bismuth after the reaction is completed, and reacting at 70°C for 3 hours, to obtain the chelated bismuth ion solution after the reaction is completed.

[0061] Comparative Example 1

[0062] A method for preparing a bismuth ion filter membrane comprises the following steps:

[0063] (1) Pretreatment of the filter membrane substrate: 4 kg of non-woven fabric was placed in a cleaning machine, 50 kg of water and 500 mL of 1 mol / L diammonium EDTA were added, and the mixture was immersed and stirred for 1 h. After the treatment, the membrane substrate was dehydrated to obtain the filter membrane substrate A.

[0064] (2) Embedding of bismuth ions: The filter membrane substrate A (4 kg) obtained in step (1) and 50 kg of chelated bismuth ion solution were added to a reactor, and then 500 g of 1 mol / L ammonium EDTA was added. The pH was adjusted to 6, the reaction pressure was 0.1 MPa, and the reaction was carried out at 30° C. for 10 min. After the reaction was completed, a filter membrane substrate embedded with bismuth ions was obtained.

[0065] (3) Post-treatment: The bismuth ion-embedded filter membrane substrate obtained in step (2) was dehydrated and then dried at 70° C. for 6 h to obtain a bismuth ion filter membrane.

[0066] The method for preparing the chelated bismuth ion solution comprises the following steps:

[0067] 50 g of flake graphite was added into 930 g of deionized water, and then 20 g of chelated bismuth was added, and the mixture was reacted at 65° C. for 3.5 h. After the reaction was completed, the chelated bismuth ion solution was obtained.

[0068] The bismuth ion filter membranes prepared in Examples 1-4 and Comparative Example 1 were subjected to antibacterial tests in accordance with GB / T 23763-2009. The test results are shown in Table 1 below:

[0069] Table 1

[0070] The filter membranes prepared in Examples 1-4 and Comparative Example 1 were made into masks, and the masks were subsequently tested for antibacterial performance. The antibacterial performance was tested after washing 50 times according to GB / T 20944.3-2008 "Antibacterial Performance Test" and the standard. The test results are shown in Table 2 below:

[0071] Table 2

[0072] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a bismuth ion filter membrane, characterized in that: The following steps are involved: (1) Pretreatment of the filter membrane substrate: Place the filter membrane substrate in a cleaning machine, add a nonionic chelating agent solution and water, soak and stir, and dehydrate after the treatment to obtain a filter membrane substrate A; (2) Embedding of bismuth ions: The filter membrane substrate A obtained in step (1) and the chelated bismuth ion solution are added to a reactor, and then a non-ionic chelating agent solution is added to react. After the reaction is completed, a filter membrane substrate embedded with bismuth ions is obtained; (3) post-treatment: dehydrating and drying the bismuth ion-embedded filter membrane substrate obtained in step (2) to obtain a bismuth ion filter membrane; The preparation method of the chelated bismuth ion solution in step (2) comprises the following steps: S1, adding flake graphite to H2O2 / H2SO4 solution, stirring at room temperature for 10 minutes, then filtering, washing, and calcining at 500-600°C for 10-20 minutes in a nitrogen atmosphere to obtain pretreated flake graphite, then adding the pretreated flake graphite to an ethanol aqueous solution with a volume ratio of 1:1, ultrasonically treating under stirring for 8-12 hours, and obtaining flaky graphite after vacuum drying; S2, adding 50 parts by weight of the flake graphite in step S1 to 920 parts by weight of deionized water, then adding 10 parts by weight of chitosan, adjusting the pH to 2-3, stirring and reacting at 40-50° C. for 4-6 hours, adding 20 parts by weight of chelated bismuth after the reaction is completed, and reacting at 60-70° C. for 3-4 hours, to obtain the chelated bismuth ion solution after the reaction is completed.

2. The method for preparing a bismuth ion filter membrane according to claim 1, wherein In the step (1), the filter membrane substrate is non-woven fabric, the non-ionic chelating agent is ammonium EDTA, and the concentration of the non-ionic chelating agent solution is 1 mol / L.

3. The method for preparing a bismuth ion filter membrane according to claim 1, wherein The soaking and stirring treatment time in step (1) is 1-2 hours.

4. The method for preparing a bismuth ion filter membrane according to claim 1, wherein In the step (1), the mass ratio of the filter membrane substrate to water is 4-8:50, and the mass ratio of the nonionic chelating agent solution to water is 1:100-1000.

5. The method for preparing a bismuth ion filter membrane according to claim 1, wherein The nonionic chelating agent in step (2) is ammonium EDTA, and the concentration of the nonionic chelating agent solution is 1 mol / L.

6. The method for preparing the bismuth ion filter membrane according to claim 1, wherein In step (2), the mass ratio of the filter membrane substrate A to the chelated bismuth ion solution is 4-8:50, and the mass ratio of the nonionic chelating agent solution to the chelated bismuth ion solution is 1:100-1000.

7. The method for preparing the bismuth ion filter membrane according to claim 1, wherein In the step (2), the reaction temperature is 30-40° C., the reaction time is 10-30 min, the reaction pressure is 0.1-0.15 MPa, and the pH is 6-7.

8. The method for preparing the bismuth ion filter membrane according to claim 1, wherein In step (3), the drying temperature is 60-90° C. and the drying time is 4-8 hours.

9. A bismuth ion filter membrane obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the bismuth ion filter membrane according to claim 9 in masks and air filters.