Device for preparing slow-release oxidized microspheres through microchannel continuous flow and preparation method of slow-release oxidized microspheres

Abstract

The invention relates to the technical field of preparation of slow-release oxidized microspheres through micro-channel continuous flow, in particular to a device for preparing slow-release oxidized microspheres through micro-channel continuous flow and a preparation method of the device. According to the technical scheme, the device for preparing the slow-release oxidized microspheres through the microchannel continuous flow comprises a first raw material premixing device, a second raw material premixing device, a third raw material premixing device, a first power device, a second power device, a third power device, a control assembly, an extended reaction assembly and a product treatment assembly, a second raw material premixing device is arranged on one side of the first raw material premixing device; according to the method, the emulsification effect and efficiency are enhanced through the micro-fluidic chip, the reaction tube is prolonged to introduce the cross-linking agent, and the final product is dried and collected through the treatment system, so that the purpose of continuously preparing the slow-release oxidized microspheres is achieved, and the technical defect that the size and the internal structure of the slow-release oxidized microspheres prepared by a traditional intermittent method are difficult to accurately control is overcome; the problems that conventional micro-fluidic equipment is complex, and continuous production and industrial mass production cannot be achieved are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparing sustained-release oxidized microspheres by microchannel continuous flow, and particularly relates to a device for preparing sustained-release oxidized microspheres by microchannel continuous flow and a preparation method thereof. Background Art

[0002] In-situ chemical oxidation (ISCO), as a mature technology for treating groundwater and soil pollutants, has problems such as short contact time of organic matter, lack of selectivity, and soil acidification caused by excessive oxidants, resulting in low utilization rate of remediation agents. In recent years, the rise of sustained-release technology has provided new solutions to these problems. This technology ensures long-term effective concentration by regulating the release rate of the active agent, improves the utilization efficiency, and has been widely applied in many fields. As a sustained-release material with a polymer carrier, it can encapsulate and support the remediation agent to achieve persistent and stable release, avoid frequent dosing, and is expected to efficiently promote long-term remediation and reduce non-target losses.

[0003] Currently, some researchers have successfully prepared sustained-release oxidants using potassium permanganate, ferrate, and persulfate. The common synthesis methods they use are mainly traditional methods such as emulsification cross-linking method, oil phase separation method, and spray drying method. The key to the synthesis of sustained-release oxidized microspheres lies in precisely controlling the size, uniformity, and structure. The traditional methods mainly control the formation of emulsion droplets by mechanical stirring, and it is difficult to precisely control the size and internal structure of the obtained templates of sustained-release oxidized microspheres, thus affecting the performance and application of the sustained-release oxidized microspheres.

[0004] In contrast, microfluidics is a technology that uses micro-sized structures to restrict fluids to precisely control the flow of fluids. It can form single O / W (W / O) or double O / W / O (W / O / W) or even higher-order template droplets by shearing multiple immiscible fluids, and then solidify to form nano / microcapsules. Using this technology, the size, shape, and structure of emulsion droplets can be precisely controlled by controlling factors such as the flow rate of liquids, flow rate ratio, viscosity, and interfacial tension. However, the current disadvantages of microfluidics technology are the complex equipment required and small production volume, so it cannot meet the requirements of continuous production and industrial mass production.

[0005] In view of this, the purpose of the present invention is to provide a microchannel continuous flow device to enable the microfluidic device to more efficiently solve the problems of actual production, precisely control the size and structure of the sustained-release oxidized microspheres, and improve the production efficiency of preparing the sustained-release oxidized microspheres. Summary of the Invention

[0006] In order to overcome the problems that the current microfluidics technology has complex equipment required and small production volume, so it cannot meet the requirements of continuous production and industrial mass production.

[0007] The technical solution of the present invention is as follows: A device for continuously preparing sustained-release oxidized microspheres in a microchannel, comprising a first raw material premixing device, a second raw material premixing device, a third raw material premixing device, a first power device, a second power device, a third power device, a control component, an extended reaction component, and a product processing component. A second raw material premixing device is arranged on one side of the first raw material premixing device, a third raw material premixing device is arranged on one side of the second raw material premixing device, a first power device is arranged on the other side of the first raw material premixing device, a second power device is arranged on one side of the first power device, and a third power device is arranged on one side of the second power device. Multiple groups of raw material premixing devices and multiple groups of power devices are connected by pipelines. A control component is arranged on one side of the first power device, an extended reaction component is arranged on the other side of the first power device, and a product processing component is arranged on one side of the extended reaction component.

[0008] Preferably, the aqueous phase and oil phase raw materials required for preparing the sustained-release oxidized microspheres are pre-mixed by the first raw material premixing device, the second raw material premixing device, and the third raw material premixing device to ensure the uniformity and stability of the raw materials. The first power device, the second power device, and the third power device provide the power required for the raw materials to enter the main microchannel chip. By precisely controlling the flow rate, the stable and continuous transportation of the raw materials is achieved. The control component precisely controls the fluid flow. The extended reaction component provides a constant temperature environment for the emulsified emulsion, and the product processing component processes the emulsion after the cross-linking reaction.

[0009] Preferably, the control component includes a main body of the microchannel main chip and an external high and low temperature integrated machine for the microchannel main chip. The main body of the microchannel main chip is connected by a pipeline to one side of the first power device.

[0010] Preferably, the extended reaction component includes a water bath heating device and a bourdon tube. The water bath heating device is arranged on one side of the main body of the microchannel main chip, and the bourdon tube is arranged inside the water bath heating device.

[0011] Preferably, the product processing component includes a spray dryer and a product collection device. The spray dryer is arranged on one side of the water bath heating device, and the product collection device is arranged below the spray dryer.

[0012] A method for continuously preparing sustained-release oxidized microspheres in a microchannel includes the following steps: S101: First, premix the aqueous phase raw material and the oil phase raw material to obtain an aqueous phase solution and an oil phase solution; S102: Mix the raw materials through the microchannel to achieve a heterogeneous mixing effect; S103: Mix the emulsion with a cross-linking agent through an extended reaction tube to carry out a cross-linking reaction; S104: Dry the obtained product; S105: Collect and evaluate the processed products.

[0013] Preferably, when premixing the raw materials, the following steps are included: S201: Add chitosan and urea to the acetic acid solution at a mass ratio of approximately 4:1, and the mass ratio of the solute to the solvent is approximately 2:25; S202: Stir in a 40°C water bath environment for 1 - 2 hours until the chitosan and urea are completely dissolved; S203: Add sodium persulfate to the solution and continue stirring for 1 - 2 hours to obtain an aqueous solution; S204: Disperse Span80 into liquid paraffin, and control the volume ratio of Span80 to liquid paraffin between 1:10 and 1:20; S205: Stir in a 40°C water bath for 0.5 - 1 hour to obtain an oil phase solution.

[0014] Preferably, when transporting the raw materials and performing microchannel emulsification, the following steps are included: S301: Set the flow rate ratio of the aqueous phase raw material to the oil phase raw material, within the range of 1:1 to 1:4; S302: Use a plunger pump to transport the aqueous phase raw material and the oil phase raw material to the microchannel main chip respectively; S303: The raw materials are mixed in a liquid-liquid heterogeneous manner in the microchannel to achieve an emulsification effect and form microdroplets.

[0015] Preferably, when performing the extended reaction and crosslinking, the following steps are included: S401: The emulsified emulsion passes through the extended reaction tube and continues to be mixed with the crosslinking agent; S402: Stir at a constant temperature in a 40°C water bath to cause the microdroplets in the emulsion to undergo a crosslinking reaction to form slow-release oxidation microspheres.

[0016] Preferably, when performing product treatment and drying, the following steps are included: S501: Centrifuge the mixture after the crosslinking reaction to remove excess liquid and unreacted raw materials; S502: Filter to obtain a solid product, and repeatedly wash the solid with petroleum ether until the supernatant is clear; S503: Wash the solid with isopropanol to remove petroleum ether; S504: Perform suction filtration on the washed solid product; S505: Vacuum dry the solid obtained by suction filtration at 40°C for 10 - 12 hours to obtain the final slow-release oxidation microsphere product.

[0017] Preferably, when collecting and evaluating the products, the following steps are included: S601: Use an electronic balance to collect the dried sustained-release oxidized microsphere product, weigh it, and record the weight. S602: Conduct various characterizations and analyses on the product, including scanning electron microscopy, X-ray energy spectroscopy, and Fourier transform infrared absorption spectroscopy, to evaluate the performance and quality of the product.

[0018] Advantages of the present invention: By enhancing the emulsification effect and efficiency through a microfluidic chip, extending the introduction of the cross-linking agent into the reaction tube, and finally drying and collecting the product through a treatment system, the purpose of continuously preparing sustained-release oxidized microspheres is achieved, overcoming the technical defect that the size and internal structure of the sustained-release oxidized microspheres prepared by the traditional batch method are difficult to precisely control, and solving the problems of complexity of conventional microfluidic devices, inability to achieve continuous production, and industrial mass production. Description of the drawings

[0019] Figure 1 Shown is a first three-dimensional structural schematic diagram of a device for continuously preparing sustained-release oxidized microspheres with a microchannel according to the present invention; Figure 2 Shown is a second three-dimensional structural schematic diagram of a device for continuously preparing sustained-release oxidized microspheres with a microchannel according to the present invention; Figure 3 Shown is a planar schematic diagram of a device for continuously preparing sustained-release oxidized microspheres with a microchannel according to the present invention; Figure 4 Shown are scanning electron microscopy (SEM) images of the sustained-release oxidized microspheres of the present invention before and after 14 days of sustained release; Figure 5 Shown is the X-ray energy spectroscopy (EDS) analysis of the sustained-release oxidized microspheres of the present invention before and after 14 days of sustained release; Figure 6 Shown are Fourier transform infrared absorption spectroscopy (FT-IR) graphs of different pH glacial acetic acid groups of the present invention;

[0020] Description of reference numerals: 111, first raw material premixing device; 112, second raw material premixing device; 113, third raw material premixing device; 121, first power device; 122, second power device; 123, third power device; 310, water bath heating device; 320, bourdon tube; 410, spray dryer; 420, product collection device; 200, main body of the microchannel main chip; 500, external microchannel main chip high and low temperature integrated machine. Detailed implementation manners

[0021] The present invention will be further described below in conjunction with the drawings and embodiments.

[0022] Please refer to Figures 1 - 3, the present invention provides an embodiment: the bath heating device 310 provides a constant temperature environment for the emulsified emulsion, ensuring that the cross-linking reaction proceeds at an appropriate temperature, improving the reaction efficiency and product quality. The spring tube 320 serves as the pipeline through which the emulsified emulsion flows, further promoting the occurrence of the cross-linking reaction and simultaneously playing a role in buffering and stabilizing the flow rate.

[0023] Preferably, the product processing assembly includes a spray dryer 410 and a product collection device 420. The spray dryer 410 is arranged on one side of the water bath heating device 310, and the product collection device 420 is arranged below the spray dryer 410. During use, the emulsion after the cross-linking reaction is spray-dried by the spray dryer 410 to remove water and solvents, obtaining a solid product of the sustained-release oxidized microspheres. The product collection device 420 collects and accurately weighs the spray-dried sustained-release oxidized microspheres to ensure the quality and quantity of the product.

[0024] A preparation method for continuously preparing sustained-release oxidized microspheres in a microchannel includes the following steps: S101: First, premix the aqueous phase raw material and the oil phase raw material to obtain an aqueous phase solution and an oil phase solution; S102: Mix the raw materials through a microchannel to achieve an emulsification effect; S103: Mix the emulsion with a cross-linking agent through an extended reaction tube to carry out a cross-linking reaction; S104: Dry the obtained product; S105: Collect and evaluate the processed product.

[0025] Preferably, when premixing the raw materials, it includes the following steps: S201: Add chitosan and urea to an acetic acid solution at a mass ratio of approximately 4:1, and the mass ratio of the solute to the solvent is approximately 2:25; S202: Stir in a 40°C water bath environment for 1 - 2 hours until the chitosan and urea are completely dissolved; S203: Add sodium persulfate to the solution and continue stirring for 1 - 2 hours to obtain an aqueous phase solution; S204: Disperse Span80 in liquid paraffin, and control the volume ratio of Span80 to liquid paraffin between 1:10 and 1:20; S205: Stir in a 40°C water bath for 0.5 - 1 hour to obtain an oil phase solution.

[0026] Preferably, when transporting the raw materials and emulsifying through the microchannel, it includes the following steps: S301: Set the flow rate ratio of the aqueous phase raw material to the oil phase raw material, ranging from 1:1 to 1:4; S302: Use a plunger pump to separately transport the aqueous phase raw material and the oil phase raw material to the main microchannel chip; S303: The raw materials achieve an emulsification effect through liquid-liquid heterogeneous mixing in the microchannel, forming micro-droplets.

[0027] Preferably, when performing the extension reaction and cross-linking, the following steps are included: S401: The emulsified emulsion passes through the extension reaction tube and continues to be mixed with the cross-linking agent; S402: Carry out constant temperature stirring in a water bath at 40°C to cause the cross-linking reaction of the micro-droplets in the emulsion, forming slow-release oxidized microspheres.

[0028] Preferably, when performing product treatment and drying, the following steps are included: S501: Centrifuge the mixture after the cross-linking reaction to remove excess liquid and unreacted raw materials; S502: Filter to obtain a solid-phase product, and repeatedly wash the solid phase with petroleum ether until the supernatant is clear; S503: Wash the solid phase with isopropanol to remove petroleum ether; S504: Carry out suction filtration on the washed solid-phase product; S505: Vacuum-dry the solid obtained by suction filtration at 40°C for 10 - 12 hours to obtain the final slow-release oxidized microsphere product.

[0029] Preferably, when performing product collection and evaluation, the following steps are included: S601: Use an electronic balance to collect the dried slow-release oxidized microsphere product, weigh and record it; S602: Carry out various characterizations and analyses on the product, including scanning electron microscopy, X-ray energy spectrum analysis, and Fourier transform infrared absorption spectroscopy, to evaluate the performance and quality of the product.

[0030] Example 1: S701: Add 0.8 g of chitosan (CS) and 0.2 g of urea (U) to 25 mL of acetic acid solution (2%). After stirring in a 40°C water bath environment for 2 hours, add 1.0 g of sodium persulfate (PS) to the solution and continue stirring for 1 hour to obtain an aqueous phase solution (dispersed phase); S702: Disperse 10 mL of Span80 into 100 mL of liquid paraffin and stir in a 40°C water bath for 0.5 - 1 hour to obtain an oil phase solution (continuous phase); S703: Set the continuous phase propulsion speed to 4 mL / min, set the ratio of the dispersed phase to the continuous phase propulsion speed to 1:4, and the dispersed phase propulsion speed to 1 mL / min; S704: Microdroplets of an emulsion with a water-oil ratio of 1:4 are formed at the outlet of the device from the mixed solution. After the reception is completed, 0.5 wt% glutaraldehyde as a crosslinking agent is slowly added to the obtained emulsion solution, and the mixture is stirred at a constant temperature in a water bath at 40 °C for 1 h for crosslinking; S705: After the crosslinking is completed, the mixture is centrifuged at 3500 r·min -1 for 30 min, the precipitate is filtered, the lower solid phase is taken, and the solid phase is repeatedly washed with petroleum ether until the supernatant is clear, and then washed with isopropanol to remove the petroleum ether, and then suction filtered. Finally, the solid obtained by suction filtration is vacuum dried at 40 °C for 10 - 12 h to obtain CS-U@PS slow-release oxidation microspheres.

[0031] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the scope of knowledge possessed by those skilled in the art.

Claims

1. A device for continuously preparing sustained-release oxidized microspheres in a microchannel, characterized in that: It includes a first raw material premixing device (111), a second raw material premixing device (112), a third raw material premixing device (113), a first power device (121), a second power device (122), a third power device (123), a control component, an extended reaction component, and a product processing component. A second raw material premixing device (112) is arranged on one side of the first raw material premixing device (111), a third raw material premixing device (113) is arranged on one side of the second raw material premixing device (112), a first power device (121) is arranged on the other side of the first raw material premixing device (111), a second power device (122) is arranged on one side of the first power device (121), and a third power device (123) is arranged on one side of the second power device (122). The multiple groups of raw material premixing devices and multiple groups of power devices are connected by pipelines. A control component is arranged on one side of the first power device (121), an extended reaction component is arranged on the other side of the first power device (121), and a product processing component is arranged on one side of the extended reaction component.

2. The device for continuously preparing sustained-release oxidized microspheres in a microchannel according to claim 1, characterized in that: The control component includes a microchannel main chip body (200) and an external microchannel main chip high and low temperature integrated machine (500). The microchannel main chip body (200) is connected by a pipeline to one side of the first power device (121).

3. The device for continuously preparing sustained-release oxidized microspheres in a microchannel according to claim 2, characterized in that: The extended reaction component includes a water bath heating device (310) and a bourdon tube (320). The water bath heating device (310) is arranged on one side of the microchannel main chip body (200), and the bourdon tube (320) is arranged inside the water bath heating device (310).

4. A device for continuously preparing sustained-release oxidized microspheres in a microchannel according to claim 3, characterized in that: The product processing component includes a spray dryer (410) and a product collection device (420). The spray dryer (410) is arranged on one side of the water bath heating device (310), and the product collection device (420) is arranged below the spray dryer (410).

5. A device for continuously preparing sustained-release oxidized microspheres in a microchannel according to claims 1-4, characterized in that: A method for preparing sustained-release oxidized microspheres by microchannel continuous flow includes the following steps: S101: First, premix the aqueous phase raw material and the oil phase raw material to obtain an aqueous phase solution and an oil phase solution; S102: Mix the raw materials through the microchannel in a heterogeneous manner to achieve an emulsification effect; S103: Mix the emulsion with a crosslinking agent through an extended reaction tube to carry out a crosslinking reaction; S104: Dry the obtained product; S105: Collect and evaluate the processed product.

6. The preparation method of sustained-release oxidized microspheres by microchannel continuous flow according to claim 5, characterized in that: When premixing the raw materials, it includes the following steps: S201: Add chitosan and urea to an acetic acid solution at a mass ratio of about 4:1, and the mass ratio of the solute to the solvent is about 2:25; S202: Stir in a 40 °C water bath environment for 1 - 2 hours until the chitosan and urea are completely dissolved; S203: Add sodium persulfate to the solution and continue to stir for 1 - 2 hours to obtain an aqueous phase solution; S204: Disperse Span80 in liquid paraffin, and control the volume ratio of Span80 to liquid paraffin between 1:10 and 1:20; S205: Stir in a 40 °C water bath for 0.5 - 1 hour to obtain an oil phase solution.

7. A preparation method of sustained-release oxidized microspheres by microchannel continuous flow according to claim 5, characterized in that: When transporting the raw materials and carrying out microchannel emulsification, it includes the following steps: S301: Set the flow rate ratio of the aqueous raw material to the oil-phase raw material, within the range of 1:1 to 1:4; S302: Use a plunger pump to separately transport the aqueous raw material and the oil-phase raw material to the main microchannel chip; S303: The raw materials achieve an emulsification effect through liquid-liquid heterogeneous mixing in the microchannel, forming microdroplets.

8. A preparation method of sustained-release oxidized microspheres by microchannel continuous flow according to claim 5, characterized in that: When performing the extension reaction and crosslinking, the following steps are included: S401: The emulsified emulsion passes through the extension reaction tube and continues to mix with the crosslinking agent; S402: Stir at a constant temperature in a water bath at 40°C to cause the crosslinking reaction of the microdroplets in the emulsion, forming slow-release oxidized microspheres.

9. A method for preparing sustained-release oxidized microspheres by microchannel continuous flow according to claim 5, characterized in that: When performing product treatment and drying, the following steps are included: S501: Centrifuge the mixture after the crosslinking reaction to remove excess liquid and unreacted raw materials; S502: Filter to obtain the solid-phase product, and repeatedly wash the solid phase with petroleum ether until the supernatant is clear; S503: Wash the solid phase with isopropanol to remove the petroleum ether; S504: Perform suction filtration on the washed solid-phase product; S505: Vacuum-dry the solid obtained by suction filtration at 40°C for 10 - 12 hours to obtain the final slow-release oxidized microsphere product.

10. A preparation method for continuously flowing microchannels to prepare sustained-release oxidized microspheres according to claim 5, characterized in that: When performing product collection and evaluation, the following steps are included: S601: Use an electronic balance to collect the dried slow-release oxidized microsphere product, weigh it, and record; S602: Perform various characterizations and analyses on the product, including scanning electron microscopy, X-ray energy spectrum analysis, and Fourier transform infrared absorption spectroscopy, to evaluate the performance and quality of the product.

Images