A method for preparing an Ag-TiO2-rGO-PAN composite film with photocatalytic activity and sterilization performance

Abstract

The application relates to a method for preparing an Ag-TiO2-rGO-PAN composite film with photocatalytic activity and sterilization performance, and belongs to the technical field of catalyst preparation and environmental functional material. The technical scheme of the application comprises the following steps: step one, dispersing graphene oxide powder in a certain volume of an ultrapure water / ethanol system respectively, and obtaining graphene oxide dispersion liquid after ultrasonic treatment; step two, weighing a certain amount of P25 TiO2 powder and adding the P25 TiO2 powder into the graphene oxide dispersion liquid to obtain a mixed liquid through stirring; step three, transferring the mixed liquid into a stainless steel high-pressure reaction kettle reactor to perform hydrothermal treatment; step four, placing the mixed liquid after the hydrothermal treatment into a centrifugal machine to perform centrifugation, washing the precipitate after the centrifugation for several times, and drying and grinding to obtain TiO2-rGO powder; step five, weighing a certain amount of PAN powder, dissolving the PAN powder in DMF to prepare a PAN solution, and performing magnetic stirring overnight; step six, loading the PAN solution and the TiO2-rGO dispersion liquid into two injection cylinders of an electrostatic spinning machine respectively; and step seven, obtaining the Ag-TiO2-rGO-PAN composite film.

Description

Technical Field

[0001] This invention relates to a method for preparing an Ag-TiO2-rGO-PAN composite membrane that combines photocatalytic activity and sterilization performance, belonging to the technical field of catalyst preparation and environmental functional materials. Background Technology

[0002] A growing body of research indicates that new or trace amounts of toxic and hazardous pollutants are being detected more frequently in wastewater treatment systems and rivers, and these pollutants are proven to pose risks to public health and aquatic ecosystems. This has gradually raised public and researcher concerns about the safety of micropollutants in water systems. Risk control of micropollutants is an urgent area of ​​focus and research, and developing novel and efficient micropollutant removal technologies is a crucial step in reducing or preventing the risks caused by micropollutants.

[0003] Among numerous technologies with high efficiency in removing micropollutants, photocatalysis stands out due to its advantages such as low energy consumption, high efficiency, and environmental friendliness, making it a promising technology for application. TiO2, with its superior catalytic performance, mature synthesis process, low cost, and stable properties, has been the subject of considerable research and application in fields such as photocatalysis.

[0004] However, TiO2 also has drawbacks such as a large band gap and the fact that it can only exert its good photocatalytic performance under ultraviolet light.

[0005] Meanwhile, in the research of photocatalytic materials, powdered carriers are the most common. Powdered photocatalysts can exert their excellent photocatalytic activity when vigorously stirred in aqueous solution, which is also due to their thorough mixing with aqueous solution, large specific surface area and active sites. However, this also makes their recycling a problem. It is difficult to fully separate dry and wet materials, and insufficient recycling may lead to secondary pollution. Furthermore, the loss of quality and performance after recycling poses challenges to their engineering applications. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties, comprising the following steps:

[0007] Step 1: Disperse graphene oxide powder in a certain volume of ultrapure water / ethanol system, and obtain graphene oxide dispersion after ultrasonic treatment.

[0008] Step 2: Weigh a certain amount of P25 TiO2 powder and add it to the graphene oxide dispersion, then stir to obtain a mixed solution;

[0009] Step 3: Transfer the mixture to a stainless steel high-pressure reactor for hydrothermal treatment;

[0010] Step 4: Centrifuge the hydrothermally treated mixture in a centrifuge, wash the precipitate several times, dry it, and grind it to obtain TiO2-rGO powder.

[0011] Step 5: Weigh a certain amount of PAN powder and dissolve it in DMF to prepare a PAN solution, then stir it magnetically overnight; at the same time, weigh a certain amount of TiO2-rGO powder, mix it with methanol and ethanol, add MEMO reagent, and stir it magnetically overnight to prepare a TiO2-rGO dispersion.

[0012] Step 6: Load the PAN solution and TiO2-rGO dispersion into the two injection cylinders of the electrospinning machine respectively, and start electrospinning. The PAN electrospun nanofibers and TiO2-rGO electrosprayed nanoparticles are simultaneously collected on the roller collector to form a composite film of nanoparticles and fibers. After the electrospinning is completed, dry the composite film for later use.

[0013] Step 7: Place the composite membrane in a reactor dish, add AgNO3 solution, place it under an ultraviolet light source, react for a certain period of time, remove the solution, take out the composite membrane, wash and dry it to obtain the Ag-TiO2-rGO-PAN composite membrane.

[0014] Preferably, in step one, the volume ratio of ultrapure water to ethanol in the ultrapure water / ethanol system is 2:1.

[0015] Preferably, in step two, the amount of P25 TiO2 powder is 5% to 10% of the mass of graphene oxide powder in step one.

[0016] As a preferred option, in step three: the lining material of the stainless steel high-pressure reactor is Teflon; during hydrothermal treatment, the reactor is heated at a heating rate of 5℃ / min until the temperature reaches 180℃, and then hydrothermally treated at 180℃ for 6 hours before being cooled to room temperature.

[0017] As a preferred embodiment, in step four: the centrifuge is centrifuged at a speed of 3500-4000 rpm for 12-15 minutes; the precipitate is washed several times with anhydrous ethanol and ultrapure water in sequence; the washed precipitate is dried in a vacuum drying oven at 60°C for 8-12 hours.

[0018] Preferably, in step five, the volume ratio of methanol to ethanol is 4:1, and the volume of MEMO reagent is 1 / 500 of the methanol-ethanol mixture.

[0019] Preferably, in step six: during electrospinning, the air humidity is below 40%; the speed of the moving platform is 50 mm / s, the scanning start point is 30 mm, and the scanning end point is 300 mm; both the PAN solution and the TiO2-rGO dispersion are fed at a constant rate through a No. 20 stainless steel needle; the voltage difference between the needle and the roller is 13-16 kV, the distance from the needle tip to the collector is 15 cm; the roller speed is 500 r / min, and the collection time is 10 h.

[0020] As a preferred embodiment, in step six: after electrospinning, the composite film is placed in a vacuum drying oven and dried at 50°C for 12 hours to remove residual solvent, and then the composite film is placed in a dry place for later use.

[0021] Preferably, in step seven, the concentration of the AgNO3 solution is 0.1–5 mg / L, and the amount of AgNO3 solution added is determined based on the reactor vessel volume and the specifications of the composite membrane.

[0022] The beneficial effects of this invention are:

[0023] 1) The Ag-TiO2-rGO-PAN composite membrane prepared by electrospinning has the advantages of high cost performance, strong catalytic activity, easy preparation, reusability, easy recycling, and low secondary pollution. The invention process is simple, the reaction conditions are relatively simple and mild, the reaction system is green, the materials are easy to recycle, and it is safe and environmentally friendly, with good and broad development prospects.

[0024] 2) The Ag-TiO2-rGO-PAN composite membrane obtained by this invention has a high specific surface area and porosity, and exhibits high catalytic activity in the process of removing emerging pollutants in water.

[0025] 3) In addition to its catalytic oxidation properties to degrade pollutants, the Ag-TiO2-rGO-PAN composite membrane obtained by this invention can also kill bacteria and other microorganisms in water, thereby improving the safety of water bodies and showing promising applications in many aspects.

[0026] 4) This invention uses graphene oxide and TiO2 composite. Graphene, as an excellent carbon nanomaterial, has the advantages of large specific surface area, good adsorption performance, good conductivity, high mechanical strength and stable properties. The combination of the two can combine the advantages of the two materials and improve the photocatalytic performance of the composite material. The loading of Ag can further improve the catalytic activity of the material under visible light conditions. Detailed Implementation

[0027] The present invention will be further described below with reference to embodiments. The description of the embodiments below is only for the purpose of helping to understand the present invention. It should be noted that those skilled in the art can make several modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0028] Example 1

[0029] As one embodiment, a method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties specifically includes the following steps:

[0030] Step 1: Weigh 50 mg of graphene oxide powder and disperse it in 90 mL of an ultrapure water / ethanol system with a volume ratio of 2:1. Sonicate the mixture in an ultrasonic bath for 3 hours to obtain a graphene oxide dispersion.

[0031] Step 2: Weigh 500mg of P25 TiO2 powder and add it to the above 90mL graphene dispersion. Mix and stir at 500rpm for 30 minutes.

[0032] Step 3: Transfer the mixture to a 150 mL Teflon-lined stainless steel autoclave reactor and perform hydrothermal treatment at 180°C for 6 hours, followed by cooling to room temperature.

[0033] Step 4: Place the reaction mixture into a centrifuge tube and centrifuge at 3900 rpm for 15 minutes. After obtaining the centrifuged precipitate, wash the precipitate several times with anhydrous ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60°C for 8 hours.

[0034] Step 5: Dissolve 1.8g PAN in 30mL DMF to prepare a 6% solution. Stir magnetically overnight until electrospinning. Separately weigh 0.5g TiO2-rGO into a beaker containing 40mL methanol and 10mL ethanol, and add 0.1mL MEMO reagent. Stir magnetically overnight as well.

[0035] Step Six: During electrospinning, if the air humidity is below 40%, a dehumidifier can be installed both indoors and inside the electrospinning machine to control the humidity inside the electrospinning machine below 25%. The PAN solution and TiO2 dispersion are loaded into two 10mL syringes respectively. The moving platform speed is maintained at 50mm / s, with a scanning start point of 30mm and a scanning end point of 300mm. Both the PAN solution and TiO2 dispersion are fed at a constant rate using a No. 20 stainless steel needle (0.99mm inner diameter). The voltage set on the needle is 13kV, and the voltage set on the roller is -2kV. The distance from the needle tip to the collector is 15cm. The roller speed is set to 500r / min, and the collection time is 10h. The composite film of nanoparticles and fibers is collected on the roller collector. After removing residual solvent, the composite film is dried in a vacuum drying oven at 50℃ for 12h and then placed in a dried box for later use.

[0036] Step 7: Cut the obtained composite membrane into approximately 5cm × 5cm pieces, place them in a glass container, and add 50mL of 2mg / L AgNO3 solution. Place the reaction system under a UV light source and irradiate for 30 minutes. After the reaction, remove the solution, take out the composite membrane, wash it, and dry it in a vacuum drying oven at 50℃ for 12 hours before use. This yields the Ag-TiO2-rGO-PAN composite membrane.

[0037] Example 2

[0038] The Ag-TiO2-rGO-PAN composite membrane obtained according to Example 1 can be used to degrade new pollutants in water and simultaneously inactivate pathogenic microorganisms such as bacteria in water. The specific usage method of this Ag-TiO2-rGO-PAN composite membrane is as follows:

[0039] The Ag-TiO2-rGO-PAN composite membrane was placed in a reaction dish, and a xenon lamp was used to simulate natural light to degrade sulfamethoxazole in water. After 2 hours of reaction, the degradation and removal rate reached 96%.

[0040] It is evident that the Ag-TiO2-rGO-PAN composite membrane prepared by the method provided in this invention has a good antibacterial effect on bacteria in water under natural light conditions.

[0041] Example 3

[0042] As another embodiment, this embodiment proposes another implementation method of the present invention for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization performance, wherein:

[0043] Step 1: Weigh 25 mg of graphene oxide powder and disperse it in 60 mL of an ultrapure water / ethanol system with a volume ratio of 2:1. Sonicate the mixture in an ultrasonic bath for 3 hours to obtain a graphene oxide dispersion.

[0044] Step 2: Weigh 500mg of P25 TiO2 powder and add it to the above 60mL graphene dispersion. Mix and stir at 500rpm for 30 minutes.

[0045] Step 3: Transfer the mixture to a 100 mL Teflon-lined stainless steel autoclave reactor and perform hydrothermal treatment at 180°C for 6 hours, then cool to room temperature;

[0046] Step 4: Place the reaction mixture into a centrifuge tube and centrifuge at 4000 rpm for 15 minutes. After obtaining the centrifuged precipitate, wash the precipitate several times with anhydrous ethanol and ultrapure water in sequence, and finally dry it in a vacuum drying oven at 60°C for 8 hours.

[0047] Steps five through seven are the same as in Example 1.

[0048] The Ag-TiO2-rGO-PAN composite membrane obtained in this embodiment degrades sulfamethoxazole in water. After 2 hours of reaction, the degradation removal rate reaches 94%. Like the Ag-TiO2-rGO-PAN composite membrane proposed in Example 2, it has a good antibacterial effect on bacteria in water.

[0049] Example 4

[0050] As another embodiment, this embodiment proposes another embodiment of the method for preparing Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization performance. The specific steps of this embodiment are the same as those of embodiment three, except that the voltage set on the needle in step six is ​​changed to 14kV and the voltage set on the roller is changed to -1kV; and the concentration of AgNO3 solution in step seven is changed to 1mg / L.

[0051] The Ag-TiO2-rGO-PAN composite membrane obtained in this embodiment degrades sulfamethoxazole in water. After 2 hours of reaction, the degradation and removal rate reaches 94%, and it also has a good antibacterial effect on bacteria in water.

Claims

1. A method for preparing an Ag-TiO2-rGO-PAN composite membrane possessing both photocatalytic activity and sterilization properties, characterized in that, Includes the following steps: Step 1: Disperse graphene oxide powder in a certain volume of ultrapure water / ethanol system, and obtain graphene oxide dispersion after ultrasonic treatment. Step 2: Weigh a certain amount of P25 TiO2 powder and add it to the graphene oxide dispersion, then stir to obtain a mixed solution; Step 3: Transfer the mixture to a stainless steel high-pressure reactor for hydrothermal treatment; Step 4: Centrifuge the hydrothermally treated mixture in a centrifuge, wash the precipitate several times, dry it, and grind it to obtain TiO2-rGO powder. Step 5: Weigh a certain amount of PAN powder and dissolve it in DMF to prepare a PAN solution, then stir it magnetically overnight; at the same time, weigh a certain amount of TiO2-rGO powder, mix it with methanol and ethanol, add MEMO reagent, and stir it magnetically overnight to prepare a TiO2-rGO dispersion. Step 6: Load the PAN solution and TiO2-rGO dispersion into the two injection cylinders of the electrospinning machine respectively, and start electrospinning. The PAN electrospun nanofibers and TiO2-rGO electrosprayed nanoparticles are simultaneously collected on the roller collector to form a composite film of nanoparticles and fibers. After the electrospinning is completed, dry the composite film for later use. Step 7: Place the composite membrane in a reactor dish, add AgNO3 solution, place it under an ultraviolet light source, react for a certain period of time, remove the solution, take out the composite membrane, wash and dry it to obtain the Ag-TiO2-rGO-PAN composite membrane. In step three: the lining material of the stainless steel high-pressure reactor is Teflon; during hydrothermal treatment, the temperature is increased at a rate of 5℃ / min until it reaches 180℃, and then hydrothermally treated at 180℃ for 6 hours before cooling to room temperature. In step four: centrifuge at 3500-4000 rpm for 12-15 minutes; wash the precipitate several times with anhydrous ethanol and ultrapure water in sequence; dry the washed precipitate in a vacuum drying oven at 60°C for 8-12 hours.

2. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step one: the volume ratio of ultrapure water to ethanol in the ultrapure water / ethanol system is 2:

1.

3. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step two: the amount of P25 TiO2 powder is 5% to 10% of the mass of graphene oxide powder in step one.

4. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step five: the volume ratio of methanol to ethanol is 4:1, and the volume of MEMO reagent is 1 / 500 of the methanol-ethanol mixed solution.

5. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step six: during electrospinning, the air humidity is below 40%; the moving platform speed is 50 mm / s, the scanning start point is 30 mm, and the scanning end point is 300 mm; both the PAN solution and the TiO2-rGO dispersion are fed at a constant rate through a No. 20 stainless steel needle; the voltage difference between the needle and the roller is 13-16 kV, the distance from the needle tip to the collector is 15 cm; the roller speed is 500 r / min, and the collection time is 10 h.

6. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step six: After electrospinning, the composite membrane is placed in a vacuum drying oven and dried at 50°C for 12 hours to remove residual solvent. Then, the composite membrane is placed in a dry place for later use.

7. The method for preparing an Ag-TiO2-rGO-PAN composite membrane with both photocatalytic activity and sterilization properties according to claim 1, characterized in that, In step seven: the concentration of AgNO3 solution is 0.1–5 mg / L, and the amount of AgNO3 solution added is determined based on the reactor vessel volume and the specifications of the composite membrane.