CN113564378B

CN113564378B - Device for reducing noble metal ions in solution by low-temperature plasma

Info

Publication number: CN113564378B
Application number: CN202110825791.1A
Authority: CN
Inventors: 潘云翔; 刘鹏; 门玉龙
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2021-07-21
Filing date: 2021-07-21
Publication date: 2022-10-25
Anticipated expiration: 2041-07-21
Also published as: CN113564378A

Abstract

The invention relates to a device for reducing noble metal ions in solution by low-temperature plasma, which comprises a shell, wherein a reaction cavity and a liquid storage cavity are arranged in the shell, the reaction cavity is positioned above the liquid storage cavity and is communicated with the liquid storage cavity, the device also comprises a solution stirring and heating mechanism matched with the liquid storage cavity, a solution circulating mechanism for communicating the top of the reaction cavity with the liquid storage cavity, a cooling reflux mechanism for communicating the reaction cavity with the liquid storage cavity, a vacuum pump communicated with the cooling reflux mechanism, a ventilation mechanism communicated with the interior of the reaction cavity and a glow discharge mechanism matched with the interior of the reaction cavity. Compared with the prior art, the method can solve the problems of solution splashing, evaporation, icing and the like in the mass production of the noble metal ions in the reduction solution, and has the advantages of simple operation, less time consumption, environmental friendliness, large disposable treatment capacity and the like.

Description

Device for reducing noble metal ions in solution by low-temperature plasma

Technical Field

The invention belongs to the technical field of reducing noble metal ions by low-temperature plasmas, and relates to a device for reducing noble metal ions in a solution by low-temperature plasmas.

Background

In recent years, low-temperature plasma has good application in modification and preparation of solid catalysts. Compared with the catalyst prepared by the traditional hydrogen reduction method, the solid catalyst prepared by the plasma has higher enrichment content of metal active components on the surface, better dispersity, smaller particle size compared with the metal particles prepared by the conventional method, adjustable action between the metal and the carrier, and higher activity and stability of the catalyst. Meanwhile, the plasma has made certain progress in the treatment of the liquid surface and the liquid interior, especially in the preparation of nano noble metal particles.

The application of noble metal nano particle colloid in the aspects of biomedicine and energy catalysis is more and more extensive. The traditional method for preparing the noble metal nano-particles mainly adopts a chemical reduction method, and the chemical reduction method needs a large amount of chemicals and has certain dangerousness. In addition, the traditional method has the defects of poor environmental friendliness, complex operation, non-uniform nano metal particles and the like. The plasma reduction method is one of effective processes for overcoming the problems, and has the advantages of simple process, environmental friendliness, safe operation, uniform particles and the like.

Although plasma-produced noble metal nanoparticles have many advantages, only a part of the literature or patents have been used to date to produce metal nanoparticles by low-temperature plasma reduction. For example, chinese invention patent CN101032754a discloses a method for preparing nano metal by low temperature plasma reduction, which adopts glow discharge plasma reduction to prepare noble metal catalyst. The reaction device used in the process is shown in figure 2-1 of the paper, "research on noble metal ions reduced by plasma aqueous phase". However, this kind of device can only realize small-scale production, and for the precious metal ion in the volume production reduction solution, this kind of device can't realize, this is because when reducing precious metal ion solution, there are liquid and easily splash, easily evaporate, easily freeze the scheduling problem under the vacuum state, and current device can not solve the risk that the raw materials was taken away by the vacuum neither, also can not prevent the solution and freeze and splash the condition when taking out the vacuum, and liquid handling capacity is few, and work efficiency is low.

Disclosure of Invention

The invention aims to provide a device for reducing noble metal ions in a solution by using low-temperature plasma, which can solve the problems of solution splashing, evaporation, icing and the like when the noble metal ions in the solution are reduced in mass production.

The purpose of the invention can be realized by the following technical scheme:

the device comprises a shell, wherein a reaction cavity and a liquid storage cavity are arranged in the shell, the reaction cavity is positioned above the liquid storage cavity and is communicated with the liquid storage cavity, the device also comprises a solution stirring and heating mechanism matched with the liquid storage cavity, a solution circulating mechanism used for communicating the top of the reaction cavity with the liquid storage cavity, a cooling reflux mechanism used for communicating the reaction cavity with the liquid storage cavity, a vacuum pump communicated with the cooling reflux mechanism, a ventilation mechanism communicated with the interior of the reaction cavity and a glow discharge mechanism matched with the interior of the reaction cavity. The solution stirring and heating mechanism is used for stirring and heating the solution in the solution storage cavity at constant temperature, the solution circulating mechanism is used for conveying the solution in the solution storage cavity to the top of the reaction cavity and enabling the solution to fall down, in the process that the solution falls down, the ventilating mechanism introduces reaction gas into the reaction cavity, meanwhile, the glow discharge mechanism starts to perform glow discharge (the power is preferably 0-1000W), and low-pressure vacuum glow plasma is generated to reduce noble metal ions in the solution. The cooling reflux mechanism is used for cooling the evaporated liquid and then refluxing the evaporated liquid to the liquid storage cavity. The vacuum pump is used for pumping the shell to a vacuum state.

Preferably, the power of the vacuum pump is 0-1000W, and the pressure in the shell can be pumped to 10-200Pa.

Further, solution stirring heating mechanism include a plurality of rotor stirring subassemblies and the hot plate of setting in the stock solution intracavity with stock solution chamber looks adaptation. The rotor stirring assembly is used for stirring the solution in the liquid storage cavity.

Preferably, the heating plates are distributed on the side wall and the bottom of the liquid storage cavity.

Further, the rotor stirring assembly comprises a rotor arranged in the liquid storage cavity and a magnetic stirrer arranged below the shell and matched with the rotor. The magnetic stirrer drives the rotor to rotate so as to realize stirring.

Further, the solution circulating mechanism comprises a solution circulating pipeline and a circulating water pump arranged on the solution circulating pipeline, the circulating water pump is located outside the shell, one end of the solution circulating pipeline is inserted into the solution storage cavity, and the other end of the solution circulating pipeline is inserted into the top of the reaction cavity.

Furthermore, the cooling reflux mechanism comprises a reflux pipeline and a cold trap arranged on the reflux pipeline, one end of the reflux pipeline is provided with a reflux pipeline inlet and is inserted into the reaction cavity, the other end of the reflux pipeline is communicated with the liquid storage cavity, and the vacuum pump is communicated with the cold trap. The liquid evaporated in the reaction cavity enters the reflux pipeline through the inlet of the reflux pipeline, then enters the cold trap for cooling, and flows back to the liquid storage cavity after being changed into liquid again.

Furthermore, a one-way valve is arranged on the return pipeline.

Furthermore, the ventilation mechanism comprises a ventilation pipe and a gas nozzle arranged at the top of the reaction chamber, the inner end of the ventilation pipe is connected with the gas nozzle, the outer end of the ventilation pipe is provided with a gas flowmeter, and the gas flowmeter is positioned outside the shell. The flow range of the gas flowmeter is 0-1000ml/min. The gas introduced by the aeration means is preferably one or more of air, argon, oxygen, nitrogen, hydrogen or carbon dioxide.

Furthermore, the outer end of the vent pipe is also provided with a needle valve connected with the gas flowmeter in parallel. In the process of vacuumizing, the magnetic stirrer drives the rotor to rotate to improve the gas separation speed dissolved in the solution, and the air input of the needle valve can be simultaneously adjusted to delay the vacuumizing speed of the vacuum pump so as to prevent the solution from splashing. The rotor speed is preferably 0-1000/min, and the nominal diameter of the needle valve is preferably 3-10mm.

Furthermore, the glow discharge mechanism comprises a pair of electrode plates which are oppositely arranged in the reaction chamber, and the gas nozzle is positioned above the electrode plates.

Further, the inside of casing still be equipped with solution circulation mechanism looks adaptation and have the fence guide plate of heating function, reaction chamber and stock solution chamber between be equipped with the reaction chamber bottom plate, the side of casing be equipped with stock solution chamber entry and stock solution chamber export that are linked together with the stock solution chamber, the casing on still be equipped with the observation window. The fence guide plate is in a hollow net shape, a strip shape or a pore plate shape structure, the material can be iron-chromium-aluminum and nickel-chromium electrothermal alloy, and the power is 0-200W. One end of the solution circulating pipeline, which is positioned in the reaction cavity, is provided with a liquid spray head, is positioned right above the fence guide plate, and is positioned below the gas spray head. The top surface of the reaction chamber bottom plate is an inclined plane, and the inclined angle of the inclined plane is preferably 15-30 degrees. The inlet of the liquid storage cavity is positioned above the outlet of the liquid storage cavity.

In practical application, the noble metal ion solution is injected into the liquid storage cavity through the inlet of the liquid storage cavity. The magnetic stirrer drives the rotor to rotate, and the vacuum pump pumps the pressure in the shell to a vacuum state. In the process of vacuumizing, along with the reduction of the pressure in the shell, the rotation of the rotor can improve the gas separation speed dissolved in the solution, and meanwhile, the air input of the needle valve is adjusted to delay the vacuumizing speed of the vacuum pump, so that the solution is prevented from splashing. When no more bubbles are separated out from the solution, the needle valve is closed, and the heating plate is used for keeping the solution at a constant temperature so as to eliminate the icing caused by the evaporation of the solution. Meanwhile, part of the evaporated solution is cooled by the cold trap and then flows back to the liquid storage cavity through the one-way valve. When the pressure in the shell reaches a vacuum state, the electrode plate and the gas flowmeter are started, reaction gas is input into the reaction cavity through the gas nozzle, meanwhile, the noble metal ion solution is conveyed to the top of the reaction cavity by the circulating water pump, a water curtain is formed by the fence guide plate with a heating function and flows back to the liquid storage cavity uniformly and slowly, and the latticed fence guide plate can promote the uniform distribution of the solution in the drainage process and does not hinder the glow discharge of the electrode plate. The inclined plane at the top of the reaction cavity bottom plate is beneficial to backflow of a small part of splashed liquid into the liquid storage cavity. And after the treatment is finished, discharging the reduced noble metal simple substance solution through an outlet of the liquid storage cavity.

Compared with the prior art, the method has the advantages of simple operation, less time consumption, environmental friendliness and large one-time treatment capacity, and can directly reduce the noble metal ions in the solution into simple substances at normal temperature. During the vacuum pumping process, the rotor rotates to improve the gas separation rate dissolved in the solution, the air inflow of the needle valve is adjusted to delay the vacuum pumping speed of the vacuum pump in a matching manner so as to prevent the solution from splashing, and the heating plate enables the solution to be always kept at a constant temperature so as to prevent the solution from freezing during the vacuum pumping; on the other hand, the cold trap may cool the vaporized liquid and return it to the reservoir via a one-way valve. In addition, can further adopt the fence guide plate that has the heating function to make solution evenly distributed, improve the contact interface of plasma and solution, and then promote noble metal ion reduction speed, prevent partial solution evaporation heat absorption icing and prevent that liquid from splashing in the cavity under the low pressure simultaneously.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the interior of the housing of the present invention;

FIG. 3 is a schematic left view of a baffle of the present invention;

the notation in the figure is:

1-shell, 2-needle valve, 3-gas flowmeter, 4-fence guide plate, 5-reaction chamber bottom plate, 6-liquid storage chamber inlet, 7-liquid storage chamber outlet, 8-circulating water pump, 9-rotor, 10-magnetic stirrer, 11-liquid storage chamber, 12-heating plate, 13-reflux pipeline inlet, 14-vacuum pump, 15-check valve, 16-cold trap, 17-electrode plate, 18-gas nozzle, 19-reaction chamber, 20-solution circulating pipeline, 21-reflux pipeline, 22-breather pipe, 23-observation window.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

The embodiment is as follows:

as shown in fig. 1 and 2, the apparatus for reducing noble metal ions in solution by using low-temperature plasma includes a housing 1, a reaction chamber 19 and a liquid storage chamber 11 are disposed inside the housing 1, the reaction chamber 19 is located above the liquid storage chamber 11 and is communicated with the liquid storage chamber 11, the apparatus further includes a solution stirring and heating mechanism adapted to the liquid storage chamber 11, a solution circulating mechanism for communicating the top of the reaction chamber 19 with the liquid storage chamber 11, a cooling and refluxing mechanism for communicating the reaction chamber 19 with the liquid storage chamber 11, a vacuum pump 14 communicated with the cooling and refluxing mechanism, a ventilation mechanism communicated with the inside of the reaction chamber 19, and a glow discharge mechanism adapted to the inside of the reaction chamber 19. The housing 1 is provided with an observation window 23.

Wherein, solution stirring heating mechanism includes a plurality of rotor stirring subassemblies and the hot plate 12 of setting in stock solution chamber 11 with stock solution chamber 11 looks adaptation. The rotor stirring assembly comprises a rotor 9 arranged in a liquid storage cavity 11 and a magnetic stirrer 10 which is arranged below the shell 1 and is matched with the rotor 9.

The solution circulating mechanism comprises a solution circulating pipeline 20 and a circulating water pump 8 arranged on the solution circulating pipeline 20, the circulating water pump 8 is positioned outside the shell 1, one end of the solution circulating pipeline 20 is inserted into the liquid storage cavity 11, and the other end of the solution circulating pipeline is inserted into the top of the reaction cavity 19.

The cooling reflux mechanism comprises a reflux pipeline 21 and a cold trap 16 arranged on the reflux pipeline 21, one end of the reflux pipeline 21 is provided with a reflux pipeline inlet 13 and is inserted in the reaction cavity 19, the other end of the reflux pipeline is communicated with the liquid storage cavity 11, and the vacuum pump 14 is communicated with the cold trap 16. The return line 21 is provided with a check valve 15.

The ventilation mechanism comprises a ventilation pipe 22 and a gas spray head 18 arranged at the top of the reaction chamber 19, wherein the inner end of the ventilation pipe 22 is connected with the gas spray head 18, the outer end is provided with a gas flowmeter 3, and the gas flowmeter 3 is positioned outside the shell 1. The outer end of the vent pipe 22 is also provided with a needle valve 2 connected in parallel with the gas flow meter 3.

The glow discharge mechanism includes a pair of electrode plates 17 disposed oppositely inside a reaction chamber 19, and a gas shower 18 is located above the electrode plates 17.

As shown in fig. 3, the interior of the housing 1 is also provided with a fence baffle 4 which is adapted to the solution circulating mechanism and has a heating function. A reaction cavity bottom plate 5 is arranged between the reaction cavity 19 and the liquid storage cavity 11, and a liquid storage cavity inlet 6 and a liquid storage cavity outlet 7 which are communicated with the liquid storage cavity 11 are arranged on the side surface of the shell 1.

In application, the noble metal ion solution is injected into the liquid storage cavity 11. Subsequently, the rotor 9 was driven to rotate at a speed of 500r/min by the magnetic stirrer 10. The vacuum pump 14 is started, and the needle valve 2 is slowly adjusted to reduce the pressure in the reaction chamber 19 to 80Pa after 5 min. After the pressure drop is completed, the needle valve 2 is closed, and the heating plate 12 is opened to maintain the temperature at about 30 ℃. At the same time, the solution obtained after cooling by the cold trap 16 flows back into the reserve chamber 11. And finally, starting the gas flow meter 3 to introduce argon (150 ml/min), starting the electrode plate 17 to perform glow discharge (150W), starting the circulating water pump 8 (2000 ml/min) to convey the noble metal ion solution to the top of the reaction chamber 19, and forming a water curtain through the fence guide plate 4 (at the temperature of 30 ℃) to uniformly and slowly flow back into the liquid storage chamber 11. And discharging the noble metal ion solution through the outlet 7 of the liquid storage cavity after the reduction of the noble metal ion solution is finished. The reduction of the noble metal ions can be observed in real time through the transparent observation window 23.

The embodiments described above are intended to facilitate a person of ordinary skill in the art in understanding and using the invention. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. The device for reducing the noble metal ions in the solution by using the low-temperature plasma is characterized by comprising a shell (1), wherein a reaction cavity (19) and a liquid storage cavity (11) are arranged inside the shell (1), the reaction cavity (19) is positioned above the liquid storage cavity (11) and communicated with the liquid storage cavity (11), the device further comprises a solution stirring and heating mechanism matched with the liquid storage cavity (11), a solution circulating mechanism for communicating the top of the reaction cavity (19) with the liquid storage cavity (11), a cooling and refluxing mechanism for communicating the reaction cavity (19) with the liquid storage cavity (11), a vacuum pump (14) communicated with the cooling and refluxing mechanism, a ventilation mechanism communicated with the inside of the reaction cavity (19) and a glow discharge mechanism matched with the inside of the reaction cavity (19);

the solution stirring and heating mechanism comprises a plurality of rotor stirring components matched with the liquid storage cavity (11) and a heating plate (12) arranged in the liquid storage cavity (11);

the cooling reflux mechanism comprises a reflux pipeline (21) and a cold trap (16) arranged on the reflux pipeline (21), one end of the reflux pipeline (21) is provided with a reflux pipeline inlet (13) and is inserted into the reaction cavity (19), the other end of the reflux pipeline is communicated with the liquid storage cavity (11), and the vacuum pump (14) is communicated with the cold trap (16).

2. A device for reducing noble metal ions in solution by low-temperature plasma according to claim 1, wherein the rotor stirring assembly comprises a rotor (9) disposed inside the reservoir (11) and a magnetic stirrer (10) disposed below the housing (1) and adapted to the rotor (9).

3. A device for reducing noble metal ions in solution by low-temperature plasma according to claim 1, wherein the solution circulating mechanism comprises a solution circulating pipeline (20) and a circulating water pump (8) arranged on the solution circulating pipeline (20), the circulating water pump (8) is positioned outside the shell (1), one end of the solution circulating pipeline (20) is inserted in the solution storage cavity (11), and the other end is inserted at the top of the reaction cavity (19).

4. A device for reducing noble metal ions in solution according to claim 1, characterized in that the return pipe (21) is provided with a check valve (15).

5. A device for reducing noble metal ions in solution by low-temperature plasma according to claim 1, wherein said ventilation means comprises a ventilation pipe (22) and a gas nozzle (18) arranged at the top of the reaction chamber (19), the inner end of said ventilation pipe (22) is connected to the gas nozzle (18), the outer end is provided with a gas flow meter (3), and the gas flow meter (3) is located outside the housing (1).

6. A device for reducing noble metal ions in solution by low-temperature plasma according to claim 5, characterized in that the outer end of the vent pipe (22) is further provided with a needle valve (2) connected in parallel with the gas flow meter (3).

7. An apparatus for reducing noble metal ions in solution according to claim 5, wherein the glow discharge mechanism includes a pair of electrode plates (17) oppositely disposed inside the reaction chamber (19), and the gas shower head (18) is located above the electrode plates (17).

8. The device for reducing noble metal ions in solution by using low-temperature plasma as claimed in claim 1, wherein a fence guide plate (4) which is matched with the solution circulating mechanism and has a heating function is further arranged inside the shell (1), a reaction cavity bottom plate (5) is arranged between the reaction cavity (19) and the liquid storage cavity (11), a liquid storage cavity inlet (6) and a liquid storage cavity outlet (7) which are communicated with the liquid storage cavity (11) are arranged on the side surface of the shell (1), and an observation window (23) is further arranged on the shell (1).