Device for preparing high-performance photocatalyst by using pulse laser

Abstract

The utility model discloses a high-performance photocatalyst preparation device utilizing pulse laser, which comprises a preparation container, a laser emission unit, an automatic deposition and collection unit and a performance evaluation unit, a three-dimensional displacement platform is arranged in the preparation container, and a metal target is arranged on the three-dimensional displacement platform. A plurality of layers of filter membranes of which the pore diameters are gradually reduced from top to bottom are arranged below the three-dimensional displacement platform at intervals; the preparation container is divided into a preparation liquid cavity and a plurality of collection liquid cavities positioned below the preparation liquid cavity by the plurality of filter membranes; collection water pumps and sampling water pumps are arranged in the collection liquid cavities, the automatic deposition collection unit is connected with the collection water pumps, and the performance evaluation unit is connected with the sampling water pumps; laser emitted by the laser emitting unit is focused on the metal target material; according to the scheme, the preparation raw materials, the preparation process and the preparation result can be effectively controlled, the performance of the prepared micro-nano particle product meets the preparation target, and the performance of the product can be systematically represented.

Description

Technical Field

[0001] The utility model relates to the technical field of photocatalyst preparation, in particular to a high-performance photocatalyst preparation device using pulsed laser. Background Art

[0002] With the development of industrialization and large-scale production activities of human beings, the problem of wastewater needs to be solved urgently. Taking dye wastewater as an example, it contains a large amount of organic matter, heavy metals and toxic components, which pose a serious threat to human life and health and the ecological environment. Traditional wastewater treatment and degradation methods, such as physical centrifugation, chemical deposition and biological oxidation, are not only insufficient to purify wastewater, but may also introduce secondary pollution. The semiconductor photocatalysis technology can convert light energy into chemical energy. By irradiating the photocatalyst with light of corresponding wavelength, photogenerated electron-hole pairs can be generated and strongly oxidizing hydroxyl radicals can be produced, thus promoting the degradation of wastewater. Moreover, with the development of nanotechnology, photocatalysts at the micro-nano scale have a larger specific surface area and exhibit better catalytic effects. Therefore, photocatalysis using micro-nano semiconductor materials is a green, efficient, economical and environmentally friendly wastewater treatment technology.

[0003] The effect of photocatalysis technology depends on the band gap and electron-hole recombination rate of the photocatalyst used. Taking titanium dioxide (TiO2), the most widely studied semiconductor catalyst material, as an example, it has low cost and no toxicity, excellent photocatalytic activity and stable physical and chemical properties, and is widely used in environmental protection problems such as wastewater treatment. However, titanium dioxide has a wide band gap (such as > 3.2 eV) and a high electron-hole recombination rate, and is only sensitive to ultraviolet light, that is, only less than 7% of solar energy can be utilized, which causes major limitations to the application of titanium dioxide. In addition, traditional preparation methods of titanium dioxide micro-nano particles, such as sol-gel method, chemical hydrothermal method, etc., will lead to serious agglomeration of products, performance degradation, difficult removal of chemical precursors or additives and easy pollution, and have various disadvantages such as complex operation and high long-term cost of purchasing reagents. These material problems and preparation problems will limit the efficiency and application of photocatalysis technology.

[0004] At present, a new, safe and efficient preparation method for micro-nano particle photocatalysts is the pulsed laser ablation in liquid method. Its advantages are that after the reaction optical path is established, only minimal operations are required to produce different micro-nano particles, and the desired target preparation can be achieved by replacing the liquid and the target material; therefore, the PLAL method does not require the purchase of additional chemical reagents or precursor molecules, has long-term economic and environmental benefits, and the product does not contain adsorbed residues or other functional groups, which is a clean, sustainable and efficient preparation method; preparing in a liquid medium has various advantages because it can control the dynamic process of non-plasma movement, limit the expansion of the plasma, and create an extreme environment of high temperature and high pressure; secondly, the quenching time of the plasma in the liquid medium is short, which means that the growth time of the micro-nano particle material in the bubble is limited, thus ensuring the size of the product; finally, the micro-nano particles are easier to collect in a liquid environment.

[0005] However, at present, there is no industrial promotion of the pulsed laser ablation in liquid method for preparing micro-nano photocatalysts, and there is a lack of research and summary on the influence of preparation parameters on the product performance, and during the preparation, the performance of the product cannot be monitored in real time. Utility Model Content

[0006] In view of the above deficiencies of the prior art, the present utility model provides a high-performance photocatalyst preparation device using pulsed laser, which solves the problem of difficult control and characterization of the product performance when preparing photocatalysts by pulsed laser.

[0007] To achieve the above object, the technical solution adopted by the present utility model is as follows:

[0008] Provide a high-performance photocatalyst preparation device using pulsed laser, which includes a preparation container, a laser emission unit, an automatic deposition and collection unit, and a performance evaluation unit. A three-dimensional displacement platform is arranged inside the preparation container, a metal target is arranged on the three-dimensional displacement platform, and several layers of filter membranes with gradually decreasing pore diameters from top to bottom are arranged at intervals below the three-dimensional displacement platform. The several filter membranes divide the preparation container into a preparation liquid cavity and several collection liquid cavities located below the preparation liquid cavity; a collection water pump and a sampling water pump are arranged in each of the several collection liquid cavities. The automatic deposition and collection unit is connected to the several collection water pumps, and the performance evaluation unit is connected to the several sampling water pumps; the laser emitted by the laser emission unit is focused on the metal target.

[0009] Further, the laser emission unit includes a laser. The laser emitted by the laser is divided into two beams of laser by a beam splitter. One beam of laser sequentially passes through a reflector and a convex lens and is focused on the metal target, and the other beam of laser is transmitted to a laser energy meter through a detection optical path transmission unit.

[0010] Further, the laser, the beam splitter, the reflector and the convex lens are all installed on an adjustment bracket.

[0011] Further, the performance evaluation unit includes one or several of an ultraviolet-visible spectrophotometer, a particle size analyzer, a fluorescence spectrometer, and an X-ray diffractometer.

[0012] Further, the preparation container is in the shape of a trough box, and a window cover is provided on the preparation container, and a light inlet for facilitating the transmission of laser is provided on the window cover.

[0013] Further, the preparation liquid chamber is connected to the liquid storage container through a liquid supply pump.

[0014] Further, the liquid in the liquid storage container is deionized water.

[0015] Further, the liquid level height in the preparation liquid chamber is maintained at 2-4 mm above the metal target.

[0016] The beneficial effects of the present utility model are as follows:

[0017] 1. In this solution, the laser emitted by the laser emission unit is focused on the metal target in the liquid phase environment and irradiated to generate laser plasma. The high temperature and high pressure of the laser plasma and the cavitation bubbles are used to generate micro-nano particles, so that the preparation of the photocatalyst is no longer limited to chemical methods (such as sol-gel method or chemical deposition method, etc.), avoiding secondary pollution and residue attachment brought by chemical precursors. Among them, the optical path of the laser emission unit is convenient to adjust. After the metal target is polished, it can be recycled. It is convenient, environmentally friendly, cost-saving, and the product performance is excellent. It is a sustainable preparation method.

[0018] 2. In this solution, the laser energy can be monitored in real time through the laser energy meter; the position of the metal target and the number of single-point pulse actions can be controlled in real time through the three-dimensional platform; micro-nano particles in each size range can be separated through filters of different sizes, so as to ensure the high visibility of the liquid phase environment in the preparation liquid chamber; the absorption spectrum of the micro-nano particle suspension can be monitored in real time through the ultraviolet-visible spectrophotometer, and performance parameters such as absorption peaks can be calculated and output to confirm the preparation situation; through the particle size analyzer, fluorescence spectrometer and X-ray diffractometer, various performance indicators of the product can be tested and output; finally, the product is collected according to the particle size by the automatic deposition collection unit, and the performance of the product is systematically characterized, so as to achieve the purpose of determining the preparation situation in real time. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of a high-performance photocatalyst preparation device using pulsed laser.

[0020] Among them, 1. Preparation container, 2. Automatic deposition and collection unit, 3. Performance evaluation unit, 4. Three-dimensional displacement platform, 5. Metal target, 6. Filter membrane, 7. Preparation liquid chamber, 8. Collection liquid chamber, 9. Collection water pump, 10. Sampling water pump, 11. Laser, 12. Beam splitter, 13. Reflector, 14. Convex lens, 15. Detection optical path transmission unit, 16. Laser energy meter, 17. UV-Vis spectrophotometer, 18. Particle size analyzer, 19. Fluorescence spectrometer, 20. X-ray diffractometer, 21. Light inlet, 22. Liquid supply pump, 23. Liquid storage container. Detailed implementation manners

[0021] The following describes the detailed implementation manners of the present utility model to facilitate those skilled in the art of this technical field to understand the present utility model. However, it should be clear that the present utility model is not limited to the scope of the detailed implementation manners. For those of ordinary skill in the art of this technical field, as long as various changes are within the spirit and scope of the present utility model defined and determined by the appended claims, these changes are obvious, and all utility models created using the concept of the present utility model are within the scope of protection.

[0022] As Figure 1 shown, the high-performance photocatalyst preparation device using pulsed laser in this solution includes a preparation container 1, a laser emission unit, an automatic deposition and collection unit 2, and a performance evaluation unit 3; a three-dimensional displacement platform 4 is arranged inside the preparation container 1. The three-dimensional displacement platform 4 can control the displacement direction and displacement speed in real time through software. A sheet-shaped metal target 5 is arranged on the three-dimensional displacement platform 4. The metal target 5 refers to the material used to prepare micro-nano photocatalysts. For example, when preparing titanium dioxide, the metal target 5 is preferably titanium.

[0023] Several layers of filter membranes 6 with gradually decreasing pore sizes from top to bottom are arranged at intervals below the three-dimensional displacement platform 4. The several filter membranes 6 divide the preparation container 1 into a preparation liquid chamber 7 and several collection liquid chambers 8 located below the preparation liquid chamber 7; among them, the preparation liquid chamber 7 is connected to the liquid storage container 23 through the liquid supply pump 22, and deionized water is supplied to the preparation container 1 through the liquid storage container 23; collection water pumps 9 and sampling water pumps 10 are arranged in each of the several collection liquid chambers 8. The automatic deposition and collection unit 2 is connected to the several collection water pumps 9, and the performance evaluation unit 3 is connected to the several sampling water pumps 10. The performance evaluation unit 3 includes a UV-Vis spectrophotometer 17, a particle size analyzer 18, a fluorescence spectrometer 19, and an X-ray diffractometer 20; the laser emitted by the laser emission unit is focused on the metal target 5.

[0024] During specific implementation, the preparation container 1 is a quartz water tank in the shape of a trough box for easy observation. A quartz window cover is arranged on the quartz water tank to prevent liquid splashing during pulsed laser ablation, avoid liquid loss due to splashing, and at the same time avoid environmental dust or other pollutants from falling into the quartz water tank. A light inlet 21 for laser to pass through is arranged on the quartz window cover.

[0025] The laser emission unit includes a laser 11. The laser 11 is preferably a near-infrared laser 11, such as a Nd:YAG laser 11, with a wavelength of 1064 nm, a pulse width of 12 ns, and a frequency of 1 Hz - 10 Hz. The laser emitted by the laser 11 is split into two beams of laser by a beam splitter 12. One beam of laser passes through a reflector 13 and a convex lens 14 in sequence and is focused on the metal target 5. The other beam of laser is transmitted to a laser energy meter 16 through a detection optical path transmission unit 15. The laser energy meter 16 can monitor the laser energy in real time. Among them, the laser 11, the beam splitter 12, the reflector 13, and the convex lens 14 are all installed on an adjustment bracket. The adjustment bracket can be any adjustable mounting bracket in the prior art, and its structure will not be described in detail.

[0026] The working principle of this solution will be specifically described below:

[0027] Before the preparation of this solution, the cleaned metal target 5 is placed on a three-dimensional displacement platform 4. Then, liquid is injected into the preparation container 1 through a liquid storage container 23, and after the liquid level is 2 - 4 mm above the metal target 5, the quartz window cover is covered. During the preparation process, the laser energy is monitored in real time, the laser parameters and the movement of the three-dimensional displacement platform 4 are controlled to ensure that the number of single-point actions of the pulsed laser on the target can be controlled, so as to improve the preparation efficiency. The liquid supply pump 22 continuously works to ensure that the liquid in the laser action area is updated in time to improve the laser penetration rate, avoid energy loss, and at the same time accelerate the micro-nano particles to pass through the multi-layer filter membrane 6 to control the particle size range of the product. The ultraviolet-visible absorption spectrum of the micro-nano particle suspension is tested by an ultraviolet-visible spectrophotometer 17 and output in real time through software. Through a particle size analyzer 18, a fluorescence spectrometer 19, and an X-ray diffractometer 20, various performance indicators of the product can be tested and output, including particle size, XRD (crystalline phase analysis), fluorescence test steady-state spectrum (electron-hole recombination rate analysis), etc. Finally, the product is collected by the automatic deposition collection unit 2 according to the particle size.

[0028] In summary, this solution can effectively control the preparation raw materials, the preparation process, and the preparation results. The performance of the prepared micro-nano particle product meets the preparation objectives, and the performance of the product is systematically characterized, so as to achieve the purpose of determining the preparation situation in real time.

Claims

1. A high-performance photocatalyst preparation device using pulsed laser, characterized in that, It includes a preparation container, a laser emission unit, an automatic deposition and collection unit, and a performance evaluation unit. Inside the preparation container, a three-dimensional displacement platform is provided. A metal target is arranged on the three-dimensional displacement platform. Below the three-dimensional displacement platform, several filter membranes with gradually decreasing pore sizes from top to bottom are arranged at intervals. The several filter membranes divide the preparation container into a preparation liquid chamber and several collection liquid chambers located below the preparation liquid chamber; in each of the several collection liquid chambers, a collection water pump and a sampling water pump are provided. The automatic deposition and collection unit is connected to the several collection water pumps, and the performance evaluation unit is connected to the several sampling water pumps; the laser emitted by the laser emission unit is focused on the metal target.

2. The high-performance photocatalyst preparation device using pulsed laser according to claim 1, characterized in that, The laser emission unit includes a laser. The laser emitted by the laser is divided into two beams of laser by a beam splitter. One of the beams of laser sequentially passes through a reflector and a convex lens and is focused on the metal target, and the other beam of laser is transmitted to a laser energy meter through a detection optical path transmission unit.

3. The high-performance photocatalyst preparation device using pulsed laser according to claim 2, characterized in that, The laser, the beam splitter, the reflector, and the convex lens are all installed on an adjustment bracket.

4. The high-performance photocatalyst preparation device using pulsed laser according to claim 1, characterized in that, The performance evaluation unit includes one or several of an ultraviolet-visible spectrophotometer, a particle size analyzer, a fluorescence spectrometer, and an X-ray diffractometer.

5. The high-performance photocatalyst preparation device using pulsed laser according to claim 1, characterized in that, The preparation container is in the shape of a trough box. A window cover is provided on the preparation container, and a light inlet for facilitating the passage of laser is provided on the window cover.

6. The high-performance photocatalyst preparation device using pulsed laser according to claim 1, characterized in that, The preparation liquid chamber is connected to a liquid storage container through a liquid supply pump.

7. The high-performance photocatalyst preparation device using pulsed laser according to claim 6, characterized in that, The liquid in the liquid storage container is deionized water.

8. The high-performance photocatalyst preparation device using pulsed laser according to claim 1, wherein The liquid level height in the preparation liquid chamber is maintained at 2-4 mm above the metal target.

Images