Method for sizing microbubbles and use thereof

Abstract

The present application provides a microbubble size grading method and its application, the microbubble size grading method comprises the following steps: (1) microbubble generation: the water inlet and water outlet of the bubble generator are put into water together, the water outlet valve is adjusted, the bubble generating device is started, and a microbubble aqueous solution is obtained; (2) microbubble membrane passing: the microbubble aqueous solution generated in step (1) is extracted under reduced pressure, and then is injected through a filtering device under pressure to obtain a graded microbubble aqueous solution; (3) microbubble size determination: the graded microbubble aqueous solution obtained in step (2) is measured by dynamic light scattering. The microbubble size grading method has good size separation and grading effect, and is simple, fast, repeatable and low in cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of polymer material application and particle screening, and relates to a size grading method of micro-bubbles and application thereof, in particular to a size grading method of micro-bubbles based on a water-based filter membrane and application thereof. BACKGROUND

[0002] Bulk micro-bubbles refer to bubbles with a diameter less than 1000 nm, including nanometer-scale bubbles. In recent years, micro-bubbles have attracted extensive attention and have been applied to many fields, such as promoting crop growth, wastewater treatment, surface cleaning, froth flotation and disease treatment. At the same time, the mechanism research on the characteristics of micro-bubbles is also continuously carried out, so that there is a higher requirement for the monodispersity of micro-bubbles.

[0003] At present, the generation methods of micro-bubbles mainly include bubble release by dissolved gas, bubble generation by air entrainment and bubble release by electrolysis. The common method for preparing micro-bubbles with narrow size distribution mainly uses a filter membrane with a certain pore size to effectively cut the gas during the generation of bubbles, but the filter membrane used is expensive and fragile. The common filter membranes in the generation of micro-bubbles are mainly polymeric high molecular material filter membranes and porous alumina filter membranes. However, there is little progress in the size grading research of micro-bubbles with wide size distribution.

[0004] CN112608504A discloses a cross-linked sulfonated polyarylether sulfone for producing micro-nano bubbles, a preparation method and a cross-linked sulfonated polyarylether sulfone membrane, and belongs to the technical field of high polymer materials. The application provides a preparation method of a cross-linked sulfonated polyarylether sulfone for producing micro-nano bubbles. The method first prepares a sulfonic acid group-containing polyarylether sulfone polymer material, then adds a cross-linking agent and stirs under ultraviolet light source irradiation to obtain a cross-linked sulfonated polyarylether sulfone for producing micro-nano bubbles. The application also provides a cross-linked sulfonated polyarylether sulfone membrane prepared by the above-mentioned cross-linked sulfonated polyarylether sulfone for producing micro-nano bubbles. The cross-linked sulfonated polyarylether sulfone membrane prepared by the application can produce uniform and stable micro-nano bubbles in water, and the produced micro-nano bubbles can be used in the commercial ultrafiltration membrane pollution cleaning process to remove the membrane pollution caused by organic pollutants in the use process of the commercial ultrafiltration membrane. However, the application does not provide a grading method of micro-nano bubbles.

[0005] Therefore, in the field, it is expected to develop a simple and fast size grading method of micro-bubbles. SUMMARY

[0006] In view of the deficiencies of the prior art, the present application aims to provide a microbubble size grading method and application thereof, in particular to a microbubble size grading method based on water-based filter membrane and application thereof.The size grading method has good size grading effect on microbubbles, and has the advantages of simple operation, rapidness, reusable filter, low price and the like.

[0007] In the present application, microbubbles refer to bubbles with a diameter less than 1000 nm.

[0008] To achieve the object of the present application, the present application adopts the following technical solutions:

[0009] In the first aspect, the present application provides a microbubble size grading method, which comprises the following steps:

[0010] (1) Microbubble generation: place the water inlet and water outlet of the bubble generator together in water, adjust the water outlet valve, start the bubble generation device, and obtain a microbubble aqueous solution;

[0011] (2) Microbubble membrane filtration: reduce the pressure to extract the microbubble aqueous solution generated in step (1), then pressurize and inject through the filtration device to obtain a graded microbubble aqueous solution;

[0012] (3) Microbubble size determination: measure the graded microbubble aqueous solution obtained in step (2) by dynamic light scattering.

[0013] The microbubble size grading method has good size separation and grading effect, is rapid, has large sample processing capacity, and is simple and fast to operate, repeatable, and low in cost.

[0014] In the present application, microbubbles are generated in ultrapure water by using a commercial bubble generation device. The bubble generation device used in the present application is a bubble generator, which is purchased from Hangzhou Xiyue New Material Technology Co., Ltd. and has a model number of AXY-200Z-NC. The ultrapure water is prepared by a Millipore Direct-Q5 UV ultrapure water machine. However, microbubbles do not necessarily have to be generated in ultrapure water, and can also be prepared by using pure water, tap water, or even river water or lake water.

[0015] Preferably, the adjustment of the water outlet valve in step (1) is to adjust the water outlet valve to the maximum. For the bubble generator with a model number of AXY-200Z-NC used in the present application, when the valve is adjusted to the maximum, the flow rate of the water outlet is 3000 mL / min.

[0016] Preferably, the working condition of the bubble generating device in step (1) is that the air chamber temperature air inflow rate is 60-600 mL / min, for example, 60 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, 400 mL / min, 450 mL / min, 500 mL / min, 550 mL / min or 600 mL / min, etc., and the generating time is 5-40 min, for example, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min or 40 min, etc.

[0017] Preferably, the pressure reduction extraction in step (2) is performed by a device with pressure, for example, a pump driven syringe extraction.

[0018] Preferably, the pump comprises a positive displacement working mode pump, for example, a KDS210 syringe pump, etc.

[0019] Preferably, the syringe comprises a needle syringe, for example, a 5 mL syringe without needle and rubber plug, etc. The use of a rubber plug-free syringe can avoid the measurement error caused by the rubber plug pollution of the bubble solution.

[0020] Preferably, the speed of the pressure injection in step (2) is 1-20 mL / min, for example, 1 mL / min, 2 mL / min, 3 mL / min, 5 mL / min, 8 mL / min, 10 mL / min, 12 mL / min, 13 mL / min, 15 mL / min, 18 mL / min or 20 mL / min, etc.

[0021] Based on the good separation effect of the filter membrane on particles, and considering that the micro-bubbles have certain deformation characteristics and may have certain deformation when passing through the filter membrane, the present application investigates the influence of the filtration rate (i.e. the injection speed during pressure injection) of the wide size distribution bubble water on its size distribution range, and obtains the optimal condition.

[0022] Preferably, the filter device in step (2) is a filter equipped with a filter membrane.

[0023] Preferably, the filter membrane comprises a water-based filter membrane.

[0024] Preferably, the water-based filter membrane comprises a water-based polyether sulfone filter membrane, for example, a Tianlong water-based polyether sulfone (PES) filter membrane.

[0025] Preferably, the pore size of the filter membrane in step (2) is 0.1-1.0 μm, for example 0.1 μm, 0.15 μm, 0.22 μm, 0.30 μm, 0.45 μm, 0.65 μm, 0.70 μm, 0.80 μm or 1.0 μm, etc. The diameter of the filter is 25 mm.

[0026] The size of the microbubbles is measured by Malvern Zetasizer Nano ZS dynamic light scattering (DLS) using 20℃ water as the dispersant. The measurement parameters are: the viscosity of 20℃ water is 1.0031 cP, and the refractive index is 1.330. The quartz cuvette PCS1115 is used as the measurement container. The ultrapure water is tested before the sample size, and the test result shows that the ultrapure water has no light scattering signal, indicating that there is no microbubble in the ultrapure water.

[0027] In a second aspect, the present application provides the use of the microbubble size grading method of the first aspect in obtaining microbubbles with a narrow size distribution.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The microbubble size grading method of the present application has good size separation and grading effect on microbubbles, and is simple, fast, large in sample processing capacity, repeatable and low in cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Figure 6 is a size range chart of the microbubbles obtained by the size grading method of Example 1-6 and Comparative Example 1.

[0031] Figure 2 Figure 7 is a size range chart of the microbubbles obtained by the size grading method of Example 7-12 and Comparative Example 1.

[0032] Figure 3 Figure 3 is a SEM image of a water-based PES filter membrane with a pore size of 0.45 μm.

[0033] Figure 4 Figure 4 is a SEM image of a water-based PES filter membrane with a pore size of 0.22 μm. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be further described below by means of specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present application and should not be regarded as specific limitations of the present application.

[0035] Example 1

[0036] In this embodiment, a microbubble size grading method is provided, which comprises the following steps:

[0037] (1) Microbubble generation: 1L of ultrapure water was taken into a 1L beaker, the water inlet and outlet of the bubble generator were placed in the beaker together, the flow rate of the water outlet was adjusted to 3000 mL / min, the bubble generator was started, the air flow rate was adjusted to 400 mL / min, and the circulation was continued for 20 min to obtain a microbubble aqueous solution;

[0038] (2) Microbubble membrane filtration: 5 mL of the microbubble aqueous solution generated in step (1) was pumped by a pump to extract the microbubble aqueous solution through a 0.45 μm pore size Jinlong water system PES filter membrane at a speed of 1 mL / min, and a 10 mL clean glass bottle was connected;

[0039] (3) Microbubble size determination: 1 mL of the microbubble aqueous solution obtained in step (2) was taken by a syringe for dynamic light scattering measurement.

[0040] Examples 2-6

[0041] Examples 2-6 are different from Example 1 only in that the injection speed in step (2) is 3 mL / min (Example 2), 5 mL / min (Example 3), 10 mL / min (Example 4), 15 mL / min (Example 5), and 20 mL / min (Example 6), respectively, and the other conditions are the same as those of Example 1.

[0042] Example 7

[0043] In this example, a microbubble size fractionation method is provided, which comprises the following steps:

[0044] (1) Microbubble generation: 1L of ultrapure water was taken into a 1L beaker, the water inlet and outlet of the bubble generator were placed in the beaker together, the flow rate of the water outlet was adjusted to 3000 mL / min, the bubble generator was started, the air flow rate was adjusted to 400 mL / min, and the circulation was continued for 20 min to obtain a microbubble aqueous solution;

[0045] (2) Microbubble membrane filtration: 5 mL of the microbubble aqueous solution generated in step (1) was pumped by a pump to extract the microbubble aqueous solution through a 0.22 μm pore size Jinlong water system PES filter membrane at a speed of 1 mL / min, and a 10 mL clean glass bottle was connected;

[0046] (3) Microbubble size determination: 1 mL of the microbubble aqueous solution obtained in step (2) was taken by a syringe for dynamic light scattering measurement.

[0047] Examples 8-12

[0048] Examples 8-12 differ from Example 7 only in that the injection rate in step (2) is 3 mL / min (Example 8), 5 mL / min (Example 9), 10 mL / min (Example 10), 15 mL / min (Example 11), 20 mL / min (Example 12), respectively, and other conditions are the same as Example 7.

[0049] Comparative Example 1

[0050] This comparative example differs from Example 1 only in that step (2) is not included, and the microbubble aqueous solution produced in step (1) is directly subjected to dynamic light scattering detection.

[0051] The size range chart of the microbubbles obtained using the size fractionation method of Examples 1-6 and Comparative Example 1 is shown in Figure 1 , where the star is the DLS peak value.

[0052] As can be seen from Figure 1 , for the bubbles produced from ultrapure water, without filtration by the filter, direct dynamic light scattering detection (Comparative Example 1), the size distribution is wide, while after filtration by the filter, the maximum size of the microbubbles can be reduced (Examples 1-6). Due to the deformability of the bubbles, within a certain range (filtration rate: 1-20 mL / min), the higher the filtration rate, the better the size fractionation effect of the microbubbles, and when the filtration rate is 20 mL / min, the maximum size of the microbubbles is already not greater than the pore size of the filter membrane used.

[0053] The size range chart of the microbubbles obtained using the size fractionation method of Examples 7-12 and Comparative Example 1 is shown in Figure 2 , where the star is the DLS peak value.

[0054] As can be seen from Figure 2 , for the bubbles produced from ultrapure water, without filtration by the filter, direct dynamic light scattering detection (Comparative Example 1), the size distribution is wide, while after filtration by the filter, the maximum size of the microbubbles can be reduced (Examples 7-12). Due to the deformability of the bubbles, within a certain range (filtration rate: 1-20 mL / min), the higher the filtration rate, the better the size fractionation effect of the microbubbles, and when the filtration rate is 15 mL / min, the maximum size of the microbubbles is already not greater than the pore size of the filter membrane used.

[0055] The SEM image of the water-based PES filter membrane with a pore size of 0.45 μm is shown in Figure 3 . The SEM image of the water-based PES filter membrane with a pore size of 0.22 μm is shown in Figure 4The water-based PES filter membrane is made of polyether sulfone ultrafine fibers which are hot-melted and adhered together, and has poor pore uniformity, but has certain bubble interception effect.

[0056] The applicant states that the present application is illustrated by the above examples for the size classification method of microbubbles and its application, but the present application is not limited to the above examples, i.e. it does not mean that the present application must rely on the above examples to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the raw materials selected by the present application, addition of auxiliary ingredients, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for size fractionation of microbubbles, characterized by, The size fractionation method of the microbubbles comprises the following steps: (1) Generation of microbubbles: the water inlet and outlet of the bubble generator are placed in water together, the outlet valve is adjusted, the bubble generating device is started, and a microbubble aqueous solution is obtained; (2) Membrane passage of microbubbles: the microbubble aqueous solution generated in step (1) is drawn under reduced pressure, and then injected under pressure through a filtration device to obtain a fractionated microbubble aqueous solution; the filtration device is a filtration device equipped with a filter membrane, and the filter membrane is a water-based filter membrane; the speed of the pressure injection is 1-20 mL / min; the pore size of the filter membrane is 0.1-1.0 μm; (3) Size determination of microbubbles: the fractionated microbubble aqueous solution obtained in step (2) is measured by dynamic light scattering.

2. The method of sizing microbubbles according to claim 1, wherein, In step (1), the outlet valve is adjusted to the maximum.

3. The method of sizing microbubbles according to claim 1, wherein, In step (1), the working conditions of the bubble generating device are: air room temperature air flow rate is 60-600 mL / min, and the generation time is 5-40 min.

4. The method of sizing microbubbles according to claim 1, wherein The water-based filter membrane includes a water-based polyether sulfone filter membrane.

5. Use of the size fractionation method of the microbubbles according to any one of claims 1-4 in obtaining microbubbles with a narrow size distribution.

Images