Active hydrogen radical generating device for targeting reduction of nickel ions in electronic waste water

Abstract

This invention discloses an active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater, relating to the field of wastewater treatment technology. It includes a main body with a rear inspection cover, a dielectric barrier discharge unit, a gas-liquid mass transfer unit, a wastewater supply unit, and an electrical control cabinet located within the main body. A sandwich-type DBD structure is formed by an inner layer of mesh ceramic, an outer layer of mesh ceramic, and a porous polyimide film. The pore sizes of these three layers are uniform and correspond one-to-one, enabling the formation of stable and uniform low-temperature plasma within micron-level micropores. This eliminates the generation of large electric arcs, significantly increasing the generation and distribution uniformity of active hydrogen radicals, achieving targeted and efficient reduction of nickel ions. Simultaneously, relying on the micro-hollow cathode effect, it enhances electron ionization efficiency, further improving the reduction reaction rate and the purity of elemental nickel.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater. Background Technology

[0002] Recovering nickel from complexed nickel plating wastewater in its elemental form can avoid the generation of nickel-containing sludge and is an important direction for nickel resource recycling and low-carbon governance. However, the reduction and recovery of complexed nickel has always been a challenge in the industry. Among existing nickel recovery methods, ion exchange and extraction can only recover nickel salts, which have low value; membrane separation can only concentrate low-concentration nickel ions and requires further processing; catalytic reduction can recover elemental nickel, but it suffers from problems such as high energy consumption, catalyst deactivation, and hydrogen evolution side reactions.

[0003] The active hydrogen radicals (H·) generated by dielectric barrier discharge (DBD) plasma can directly break the chemical bonds between nickel ions and coordinated organic matter without the need for oxidation and complex breaking, and are not affected by water quality, making them suitable for the treatment of complex electronic wastewater. However, existing DBD nickel ion reduction devices have defects such as unstable discharge, insufficient gas-liquid contact, lack of tail gas treatment, and difficulty in recovering elemental nickel, which make it difficult to meet the needs of industrial applications.

[0004] Therefore, there is an urgent need to develop an active hydrogen radical generator that is structurally sound, stable in operation, environmentally friendly, efficient, and capable of recovering nickel resources, in order to address the pain points of existing technologies and promote the industrial application of nickel recovery from electronic wastewater. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an active hydrogen radical generator for the targeted reduction of nickel ions in electronic wastewater.

[0006] The technical solution of the present invention: an active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater, comprising a device body with a maintenance cover on the rear side, a dielectric barrier discharge unit, a gas-liquid mass transfer unit, a waste liquid supply unit, and an electrical control cabinet disposed within the device body; The device has a through-hole at the center of the upper end, and a sealed reaction chamber is movably installed at the through-hole. The side wall of the sealed reaction chamber is provided with a drain / air port, a water inlet and an air inlet. The dielectric barrier discharge unit includes several inner mesh ceramics arranged in parallel inside a sealed reaction chamber, an outer mesh ceramic sleeved on the outer wall of each inner mesh ceramic, and a dielectric barrier layer disposed between the outer mesh ceramic and the corresponding inner mesh ceramic. The inner side of the inner mesh ceramic is provided with a cathode, and the outer side of the outer mesh ceramic is provided with an anode. The cathode and the anode together constitute a high-energy electric field. The gas-liquid mass transfer unit includes a high-pressure atomizing nozzle connected to the water inlet, a water pump connected to the high-pressure atomizing nozzle, and a liquid ammonia tank connected to the air inlet. A liquid ammonia rotor flow meter is provided at the connection between the liquid ammonia tank and the air inlet. The waste liquid supply unit includes a water tank connected to the water pump and an electric valve for connecting the water tank to the bottom of the sealed reaction tank. The electrical control cabinet is electrically connected to the anode, cathode, water pump, liquid ammonia rotor flow meter, and electric valve.

[0007] Furthermore, the dielectric barrier layer is made of a porous polyimide film, and the pore size of the inner mesh ceramic, the outer mesh ceramic, and the dielectric barrier layer is 5-8 μm, with the pores of the inner mesh ceramic, the outer mesh ceramic, and the dielectric barrier layer corresponding one-to-one.

[0008] Description: The porous polyimide film exhibits excellent insulation, high-voltage breakdown resistance, and chemical corrosion resistance, making it suitable for high-energy electric field environments with dielectric barrier discharge (DBD). The outer mesh ceramic layer serves as the high-voltage anode, and the inner mesh ceramic layer as the micro-hollow cathode. All three layers have uniformly defined pore sizes of 5-8 μm, forming a complete sandwich-type DBD structure. This structure provides a channel for the electric field to penetrate the dielectric barrier layer and connect the micropores, while also preventing the formation of large arcs due to the dielectric barrier effect. This ensures that a large amount of uniform, soft, low-temperature plasma is formed only within the micron-sized micropores of the inner mesh ceramic layer, achieving stable micro-discharge, increasing the generation of active hydrogen radicals, and providing Ni at the micropore interface of the inner mesh ceramic layer. 2+ This lays the foundation for the reduction reaction.

[0009] Furthermore, a gas distributor is connected inside the air inlet.

[0010] Note: The ammonia gas output from the liquid ammonia tank enters the sealed reaction chamber through the inlet, providing a hydrogen source for the discharge process. This assists in the high-energy electron ionization to generate active hydrogen free radicals, enhancing the Ni... 2+ If ammonia gas is directly introduced into the sealed reaction chamber through the inlet, it can easily lead to gas accumulation, excessively high local concentrations, and uneven distribution, which in turn can cause Ni to be trapped within the micropores of the inner mesh ceramic layer. 2+ The reduction reaction is uneven and the reduction efficiency is low. Adding a gas distributor can divert and diffuse the ammonia gas input from the inlet, ensuring uniform dispersion of the ammonia gas inside the sealed reaction chamber. This allows for full contact with the atomized electrolyte sprayed from the high-pressure atomizing nozzle, increasing the gas-liquid contact area and providing a stable hydrogen source environment for the dielectric barrier discharge unit. This stabilizes the concentration of active hydrogen free radicals generated and further enhances Ni… 2+ Reduce activity and improve the pass rate of nickel ion removal in electronic wastewater.

[0011] Furthermore, the gas distributor includes a first hollow manifold connected to the interior of the air inlet, several first jet columns disposed on one side of the first hollow manifold, a second hollow manifold with several through-holes on its sidewall allowing the first jet columns to pass through, and several second jet columns disposed on the sidewall of the second hollow manifold and staggered with each of the first jet columns. Several vent pipes connect the first hollow manifold and the second hollow manifold, and each vent pipe and each of the first jet columns is equipped with a solenoid valve.

[0012] Description: The gas distributor adopts a distributed structure with a double-layer manifold and staggered jet columns. Ammonia gas input at the inlet first enters the first hollow manifold for initial stabilization and pressure regulation, preventing airflow fluctuations from affecting discharge stability. A portion of the ammonia gas is directly ejected through the first jet column, while the other portion is transported through a vent pipe to the second hollow manifold and ejected by the second jet column. The on / off state and gas flow rate can be controlled separately under the control of the electrical control cabinet, and can be adjusted according to the Ni content of the electronic wastewater in the water tank. 2+ The concentration and the amount of water pumped for treatment can be flexibly adjusted to control the ammonia supply and the jetting mode. At the same time, the solenoid valves on the first or second jetting column can be opened and closed alternately through the control cabinet, so that the first jetting column on the first hollow manifold and the second jetting column on the second hollow manifold can serve as maintenance backups for each other.

[0013] Furthermore, each of the first jet columns and each of the second jet columns is connected to a linkage plate at its free end. The linkage plate is provided with vents at the locations corresponding to the first and second jet columns. The linkage plate is connected to the inner wall of the sealed reaction chamber by an electric telescopic rod, and both the first and second jet columns are folded flexible hoses.

[0014] Description: The ammonia injection position is dynamically controlled through the cooperation of the electric telescopic rod, the linkage plate, and the folded hose-type jet column. The first and second jet columns are made of folded hose material and can be flexibly extended and retracted under the action of the linkage plate. The vent on the linkage plate ensures smooth delivery of ammonia. The control cabinet controls the electric telescopic rod to push the linkage plate to move, bringing the first and second jet columns closer to the atomized electrolyte area sprayed from the high-pressure atomizing nozzle, enhancing the gas-liquid mixing effect of ammonia and electrolyte, and providing a sufficient hydrogen source for discharge. During the nickel element deposition stage, the linkage plate can be retracted by the electric telescopic rod, and the first and second jet columns can be moved to interfere with the adhesion and stacking of nickel atoms generated by reduction on the surface of the inner layer of mesh ceramic micropores.

[0015] Furthermore, the drain / gas outlet is connected to a tail gas treatment tower via a pipeline. The tail gas treatment tower is equipped with an acidic absorbent liquid layer for absorbing unreacted ammonia gas. An online detector is installed at the exhaust end of the tail gas treatment tower. The exhaust end and the inlet end of the tail gas treatment tower are connected by a return pipeline and a one-way valve is installed at the connection. The online detector is electrically connected to the electrical control cabinet.

[0016] Explanation: Unreacted ammonia in the sealed reaction chamber enters the tail gas treatment tower through the drain / gas inlet. The acidic absorbent layer in the tower neutralizes the ammonia, efficiently adsorbing residual ammonia and achieving harmless treatment of the tail gas. The online detector monitors the ammonia concentration and harmful impurity content in the exhaust gas in real time and transmits the detection data to the electrical control cabinet. If the detected concentration exceeds the standard, the electrical control cabinet automatically controls the one-way valve to open, and the non-compliant tail gas is re-transported to the tail gas treatment tower for secondary purification through the return pipeline. The one-way valve can prevent the backflow of purified gas, meeting industrial environmental protection emission standards.

[0017] Furthermore, the inner mesh ceramic layer, the corresponding outer mesh ceramic layer, and the dielectric barrier layer are connected by an insulating fastener.

[0018] Description: The insulating fastener can tightly splice and fix the inner mesh ceramic, outer mesh ceramic and dielectric barrier layer to avoid structural misalignment or displacement. The insulating fastener has excellent insulation, high voltage resistance and corrosion resistance properties. It can isolate stray current between the outer mesh ceramic and the inner mesh ceramic, and ensure that the high-energy electric field acts stably on the micron-level micropores of the inner mesh ceramic, so as to give full play to the micro hollow cathode effect.

[0019] Furthermore, it also includes a nickel element recovery unit, which includes an ultrasonic transducer disposed on the inner wall of the sealed reaction chamber, a conical collecting hopper disposed at the bottom of the sealed reaction chamber, a discharge pipe communicating with the bottom of the conical collecting hopper, a discharge valve disposed on the discharge pipe, and a nickel powder collecting tank connected to the end of the discharge pipe; the ultrasonic transducer and the discharge valve are respectively electrically connected to the electrical control cabinet.

[0020] Note: Ni 2+A reduction reaction occurs at the micropore interface of the inner layer of the dielectric barrier discharge unit. The generated nickel atoms adhere in situ to the micropore surface of the lower inner layer of the mesh ceramic. After continuous discharge, the nickel atoms continuously stack and grow to form elemental nickel. Some nickel powder easily adheres to the surface of the inner and outer mesh ceramics and the inner wall of the sealed reaction chamber, making it difficult to fall off naturally. The ultrasonic transducer can be started under the control of the electrical control cabinet to generate high-frequency ultrasonic waves. The cavitation effect is used to shake off the elemental nickel powder adhering to the inner wall of the sealed reaction chamber, the inner and outer mesh ceramics, and the surface of the mesh ceramics, avoiding micropore blockage and ensuring smooth electrolyte circulation and stable discharge. The conical collection hopper adopts a structure that is narrow at the bottom and wide at the top, which facilitates the rapid collection of the shaken-off elemental nickel powder to the bottom under the action of gravity. The electrical control cabinet can automatically control the opening and closing of the discharge valve and periodically transport the nickel powder in the conical collection hopper to the nickel powder collection tank through the discharge pipe to achieve automated separation and recovery of elemental nickel.

[0021] The beneficial effects of this invention are: (1) The present invention uses an inner layer of mesh ceramic, an outer layer of mesh ceramic and a porous polyimide film to form a sandwich DBD structure. The mesh pore sizes of the three are uniform and correspond one-to-one. Stable and uniform low-temperature plasma can be formed in the micron-level micropores, eliminating the generation of coarse electric arcs, significantly improving the generation and distribution uniformity of active hydrogen free radicals, and realizing the targeted and efficient reduction of nickel ions. At the same time, relying on the micro hollow cathode effect, the electron ionization efficiency is enhanced, further improving the reduction reaction rate and the purity of elemental nickel. Relying on the active hydrogen free radicals generated by dielectric barrier discharge, the chemical bonds between nickel ions and coordinating organic matter can be directly broken without the need for additional oxidation and complex breaking processes, effectively simplifying the processing flow and reducing energy consumption and reagent consumption. (2) By adding a gas distributor and adopting a structure design of double-layer manifold, staggered jet column and folded hose, combined with the dynamic control of electric telescopic rod, the uniform distribution of ammonia and flexible adjustment of the injection position can be achieved, so that ammonia and electrolyte sprayed by high-pressure atomizing nozzle can fully contact and mix, greatly increasing the gas-liquid contact area, providing a stable and sufficient hydrogen source for the discharge process, effectively solving the problem of gas accumulation and uneven distribution in the existing device, improving the utilization rate of active hydrogen free radicals, and thus improving the nickel ion removal qualification rate and the efficiency of elemental nickel preparation; (3) Add a nickel element recovery unit. The cavitation effect of the ultrasonic transducer shakes off the nickel powder adhering to the electrode and the inner wall of the reaction chamber, avoiding micropore blockage and ensuring long-term stable operation of the device. The conical collection hopper facilitates the collection of nickel powder. The electrical control cabinet controls the discharge valve to automatically discharge the material, realizing the automated separation and recovery of nickel element, reducing the loss of nickel resources, reducing the cost of manual recycling, and improving the recycling value of nickel resources. (4) The overall structure of the device is compact, and the sealed reaction box is movable, which is convenient for inspection and maintenance. The electrical control cabinet realizes centralized automatic control of each unit, which is convenient to operate and can flexibly adjust the reaction parameters according to the nickel ion concentration of wastewater and the amount of water to be treated. The device is made of high pressure resistant and corrosion resistant materials, and is not affected by the salt content of water or corrosive impurities. It can be widely adapted to high salt and strong corrosion electronic nickel wastewater treatment scenarios and has extremely strong industrial practical value. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the internal structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the external structure of Embodiment 1 of the present invention; Figure 3 This is a top view of the dielectric barrier discharge unit of the present invention; Figure 4 This is a cross-sectional view showing the distribution of the inner mesh ceramic layer, the outer mesh ceramic layer, and the dielectric barrier layer of the present invention. Figure 5 This is a schematic diagram of the internal structure of Embodiment 6 of the present invention; Figure 6 This is a schematic diagram of the gas distributor of the present invention; Figure 7 This is a physical image of Embodiment 1 of the present invention.

[0023] Among them, 1-main body of the device, 10-inspection cover plate, 11-through port, 12-sealed reaction box, 120-drain / gas port, 121-water inlet, 122-gas inlet, 14-gas distributor, 140-first hollow manifold, 141-first jet column, 142-second hollow manifold, 1420-through port, 143-second jet column, 144-vent pipe, 145-solenoid valve, 15-linkage plate, 150-vent, 151-electric telescopic rod, 2-dielectric barrier discharge unit, 20-inner layer mesh ceramic. 21-Outer layer mesh ceramic, 22-Medium barrier layer, 23-Insulating fastener, 3-Gas-liquid mass transfer unit, 30-High-pressure atomizing nozzle, 31-Water pump, 32-Liquid ammonia tank, 320-Liquid ammonia rotor flow meter, 4-Waste liquid supply unit, 40-Water tank, 41-Electric valve, 5-Electrical control cabinet, 7-Nickel element recovery unit, 70-Ultrasonic transducer, 71-Conical collection hopper, 72-Discharge pipe, 73-Discharge valve, 74-Nickel powder collection tank, 8-Tail gas treatment tower, 80-Online detector, 81-Return pipeline, 82-Check valve. Detailed Implementation

[0024] Example 1: As Figure 1 , 2As shown, the active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater includes a device body 1 with a maintenance cover 10 on the rear side, a dielectric barrier discharge unit 2, a gas-liquid mass transfer unit 3, a waste liquid supply unit 4 and an electrical control cabinet 5 located in the device body 1. The electrical control cabinet 5 adopts existing technology, such as the XL-21 power electrical control cabinet. The main body 1 of the device has a through-hole 11 at the center of the upper end. A sealed reaction box 12 is movably installed at the through-hole 11. The side wall of the sealed reaction box 12 is provided with a drain / air port 120, a water inlet 121 and an air inlet 122. like Figure 3 , 4 As shown, the dielectric barrier discharge unit 2 includes 16 inner mesh ceramics 20 arranged in parallel inside the sealed reaction chamber 12, an outer mesh ceramic 21 sleeved on the outer wall of each inner mesh ceramic 20, and a dielectric barrier layer 22 disposed between the outer mesh ceramic 21 and the corresponding inner mesh ceramic 20. The inner side of the inner mesh ceramic 20 is provided with a cathode, and the outer side of the outer mesh ceramic 21 is provided with an anode. The cathode and the anode together constitute a high-energy electric field. The 16 inner mesh ceramics 20 are arranged in a 4×4 matrix, with a center-to-center distance of 8-10cm between adjacent inner mesh ceramics 20. This ensures that the discharge area uniformly covers the interior of the sealed reaction chamber 12, avoiding discharge blind spots and ensuring the uniformity of electronic wastewater treatment. The inner mesh ceramics 20 are cylindrical structures with a length adapted to the internal height of the sealed reaction chamber 12. The cathode is fixed to its inner wall with high-temperature conductive adhesive. The cathode uses a mesh titanium electrode, which is completely attached to the inner wall of the inner mesh ceramics 20, ensuring that the cathode can uniformly receive electric field signals. The outer mesh ceramics 20 are cylindrical structures of the same specifications as the inner mesh ceramics 20. The anode is also fixed to its outer wall with high-temperature conductive adhesive. The anode uses a mesh stainless steel electrode, which is completely attached to the outer wall of the outer mesh ceramics 21. The cathode and anode are one-to-one and coaxially arranged. After being energized, they together form a uniformly distributed high-energy electric field. The electric field strength can be adjusted by the electrical control cabinet 5 to adapt to the treatment needs of electronic wastewater of different concentrations. The dielectric barrier layer 22 is made of porous polyimide film. The pore size of the inner mesh ceramic 20, the outer mesh ceramic 21, and the dielectric barrier layer 22 is all 5μm. The pores of the inner mesh ceramic 20, the outer mesh ceramic 21, and the dielectric barrier layer 22 correspond one-to-one. The porous polyimide film has good insulation performance, high voltage breakdown resistance, and chemical corrosion resistance, making it suitable for the high-energy electric field environment of dielectric barrier discharge. The outer mesh ceramic 21 serves as the high-voltage anode, and the inner mesh ceramic 20... As micro-hollow cathodes, the three meshes are uniformly limited to 5-8 μm with one-to-one correspondence, forming a complete sandwich-type DBD structure. This provides a channel for the electric field to pass through the dielectric barrier layer 22 and the through-holes, while also preventing the formation of large electric arcs by utilizing the dielectric barrier effect. This ensures that a large amount of uniform and soft low-temperature plasma is formed only within the micron-sized micropore cavity of the inner mesh ceramic 20, achieving stable micro-discharge, increasing the generation of active hydrogen free radicals, and providing Ni at the micropore interface of the inner mesh ceramic 20. 2+ This lays the foundation for reduction reactions; The inner mesh ceramic 20 is connected to the corresponding outer mesh ceramic 21 and the dielectric barrier layer 22 by an insulating fastener 23. The insulating fastener 23 can tightly splice and fix the inner mesh ceramic 20, the outer mesh ceramic 21 and the dielectric barrier layer 22 to avoid structural displacement and misalignment. The insulating fastener 23 has excellent insulation, high voltage resistance and corrosion resistance properties. It can isolate stray current between the outer mesh ceramic 21 and the inner mesh ceramic 20, and ensure that the high-energy electric field acts stably on the micron-level micropores of the inner mesh ceramic 20, so as to give full play to the micro hollow cathode effect. The insulating fastener 23 can adopt existing technologies such as alumina ceramic clamps / buckles and PTFE insulating jackets, and no special limitation is made here. The gas-liquid mass transfer unit 3 includes a high-pressure atomizing nozzle 30 connected to the water inlet 121, a water pump 31 connected to the high-pressure atomizing nozzle 30, and a liquid ammonia tank 32 connected to the air inlet 122. A liquid ammonia rotor flow meter 320 is provided at the connection between the liquid ammonia tank 32 and the air inlet 122. The waste liquid supply unit 4 includes a water tank 40 connected to the water pump 31 and an electric valve 41 for connecting the water tank 40 to the bottom of the sealed reaction chamber 12. The high-pressure atomizing nozzle 30, the water pump 31, the liquid ammonia rotor flow meter 320, and the electric valve 41 all adopt existing technologies. For example, the high-pressure atomizing nozzle 30 can be an FD-2.0 / 10 type stainless steel / ceramic core high-pressure fine atomizing nozzle, the water pump 31 can be a CDL2-15 stainless steel high-pressure centrifugal pump, the liquid ammonia rotor flow meter 320 can be an LZB-10F liquid ammonia rotor flow meter, and the electric valve 41 can be a Q941F-16P type electric ball valve. The electrical control cabinet 5 is electrically connected to the anode, cathode, water pump 31, liquid ammonia rotor flow meter 320, and electric valve 41.

[0025] Example 2: The difference between this example and Example 1 is that the mesh size of the outer mesh ceramic 21 and the dielectric barrier layer 22 is 7μm.

[0026] Example 3: The difference between this example and Example 1 is that the mesh size of the outer mesh ceramic 21 and the dielectric barrier layer 22 is 8μm.

[0027] Example 4: This example differs from Example 2 in that: Figure 6 As shown, a gas distributor 14 is connected inside the inlet 122. Ammonia gas output from the liquid ammonia tank 32 enters the sealed reaction chamber 12 through the inlet 122, providing a hydrogen source for the discharge process. This assists in the high-energy electron ionization to generate active hydrogen free radicals, enhancing the Ni... 2+ If ammonia gas is directly introduced into the sealed reaction chamber 12 through the inlet 122, it is easy for gas to accumulate, resulting in excessively high local concentrations and uneven distribution. This can lead to Ni degradation within the micropores of the inner mesh ceramic 20. 2+ The reduction reaction is uneven and the reduction efficiency is low. Adding a gas distributor 14 can divert and diffuse the ammonia gas input through the inlet 122, ensuring that the ammonia gas is evenly dispersed inside the sealed reaction chamber 12 and fully contacts the atomized electrolyte sprayed from the high-pressure atomizing nozzle 30. This increases the gas-liquid contact area, provides a stable hydrogen source environment for the dielectric barrier discharge unit 2, stabilizes the concentration of active hydrogen free radicals generated, and further enhances Ni… 2+ Reduce activity and improve the pass rate of nickel ion removal from electronic wastewater; The gas distributor 14 includes a first hollow manifold 140 connected to the interior of the air inlet 122, nine first jet columns 141 disposed on one side of the first hollow manifold 140, a second hollow manifold 142 with nine through-holes 1420 on its sidewall allowing the first jet columns 141 to pass through, and six second jet columns 143 disposed on the sidewall of the second hollow manifold 142 and staggered with each of the first jet columns 141. Six vent pipes 144 connect the first hollow manifold 140 and the second hollow manifold 142. Each vent pipe 144 and each of the first jet columns... Each column 141 is equipped with a solenoid valve 145; the gas distributor 14 adopts a distributed structure with a double-layer manifold and staggered jet columns. The ammonia gas input through the air inlet 122 first enters the first hollow manifold 140 to complete the initial manifold and voltage stabilization, avoiding airflow fluctuations from affecting the discharge stability. Part of the ammonia gas is directly ejected through the first jet column 141, and the other part is transported to the second hollow manifold 142 through the vent pipe 144 and ejected by the second jet column 143. Under the control of the electrical control cabinet 5, the on / off state and the airflow can be controlled separately, and the ammonia gas can be adjusted according to the Ni content of the electronic wastewater in the water tank 40. 2+The concentration and the amount of water pumped by the water pump 31 can be flexibly adjusted to control the ammonia supply and the jet mode. At the same time, the solenoid valves 145 on the first jet column 141 or the second jet column 143 can be opened and closed alternately through the control cabinet 5, so that the first jet column 141 on the first hollow manifold 140 and the second jet column 143 on the second hollow manifold 142 can be used as maintenance backups for each other. The solenoid valve 145 adopts existing technology, such as the VX2120 high-frequency miniature solenoid valve. Each first jet column 141 and each second jet column 143 is connected at its free end to a linkage plate 15. The linkage plate 15 has vents 150 corresponding to the first and second jet columns 141 and 143. The linkage plate 15 is connected to the inner wall of the sealed reaction chamber 12 via an electric telescopic rod 151. Both the first and second jet columns 141 and 143 are folded flexible hoses. Through the cooperation of the electric telescopic rod 151, the linkage plate 15, and the folded flexible hose jet columns, the ammonia injection position can be dynamically adjusted. The first and second jet columns 141 and 143 are made of folded flexible hoses and can flexibly extend and retract under the action of the linkage plate 15. The vents on the linkage plate 15... 150 ensures smooth ammonia delivery. The electrical control cabinet 5 controls the electric telescopic rod 151 to push the linkage plate 15 to move, causing the first jet column 141 and the second jet column 143 to approach the atomized electrolyte area sprayed by the high-pressure atomizing nozzle 30, thereby enhancing the gas-liquid fusion effect of ammonia and electrolyte and providing a sufficient hydrogen source for discharge. During the nickel element deposition stage, the linkage plate 15 can be contracted by the electric telescopic rod 151, and the first jet column 141 and the second jet column 143 can be driven to interfere with the adhesion and stacking of nickel atoms generated by reduction on the microporous surface of the lower inner layer mesh ceramic 20. The electric telescopic rod 151 adopts existing technology, such as the DTZ-50-100 type electric telescopic rod.

[0028] Example 5: This example differs from Example 4 in that: the drain / gas inlet 120 is connected to a tail gas treatment tower 8 via a pipeline. The tail gas treatment tower 8 contains an acidic absorbent liquid layer for absorbing unreacted ammonia, and an online detector 80 is installed at the exhaust end of the tail gas treatment tower 8. The exhaust end and the inlet end of the tail gas treatment tower 8 are connected by a return pipeline 81, and a one-way valve 82 is installed at the connection. The online detector is electrically connected to the electrical control cabinet 5. Unreacted ammonia in the sealed reaction chamber 12 enters the tail gas treatment tower 8 through the drain / gas inlet 120. The acidic absorbent liquid layer in the tower neutralizes the ammonia, efficiently adsorbing residual ammonia and achieving harmless treatment of the tail gas. The online detector 80 monitors the ammonia in the exhaust gas in real time. The concentration and content of harmful impurities are measured and the detection data is transmitted to the electrical control cabinet 5. If the concentration exceeds the standard, the electrical control cabinet 5 automatically controls the one-way valve 82 to open, and the non-compliant exhaust gas is re-transported to the exhaust gas treatment tower 8 for secondary purification through the return pipeline 81. The one-way valve 82 can prevent the backflow of purified gas and meet industrial environmental emission standards. The exhaust gas treatment tower 8, the online detector 80, and the one-way valve 82 all adopt existing technologies. For example, the exhaust gas treatment tower 8 can be a ZSXD-100 exhaust gas treatment tower, the online detector 80 can be a MIC-500S-NH3 online detector, and the one-way valve 82 can be an H41F-16P one-way valve. The acidic absorption liquid layer is a 3% dilute hydrochloric acid.

[0029] Example 6: This example differs from Example 5 in that: Figure 5 , 7 As shown, it also includes a nickel element recovery unit. The nickel element recovery unit 7 includes an ultrasonic transducer 70 installed on the inner wall of the sealed reaction chamber 12, a conical collecting hopper 71 installed at the bottom of the sealed reaction chamber 12, a discharge pipe 72 connected to the bottom of the conical collecting hopper 71, a discharge valve 73 installed on the discharge pipe 72, and a nickel powder collecting tank 74 connected to the end of the discharge pipe 73; the ultrasonic transducer 70 and the discharge valve 73 are electrically connected to the electrical control cabinet 5. 2+A reduction reaction occurs at the micropore interface of the inner layer mesh ceramic 20 in the dielectric barrier discharge unit 2. The generated nickel atoms adhere in situ to the micropore surface of the lower inner layer mesh ceramic 20. After continuous discharge, the nickel atoms continuously stack and grow to form elemental nickel. Some nickel powder easily adheres to the surface of the inner layer mesh ceramic 20, the outer layer mesh ceramic 21, and the inner wall of the sealed reaction chamber 12, making it difficult to fall off naturally. The ultrasonic transducer 70 can be started under the control of the electrical control cabinet 5 to generate high-frequency ultrasonic waves. The cavitation effect is used to shake off the elemental nickel powder adhering to the inner wall of the sealed reaction chamber 12, the surface of the inner layer mesh ceramic 20, and the outer layer mesh ceramic 21, thus avoiding... To prevent micropore clogging and ensure smooth electrolyte circulation and stable discharge, the conical collecting hopper 71 adopts a narrow bottom and wide top structure, which facilitates the rapid accumulation of nickel elemental powder at the bottom due to gravity. The electrical control cabinet 5 can automatically control the opening and closing of the discharge valve 73, and periodically transport the nickel powder in the conical collecting hopper 71 to the nickel powder collecting tank 74 through the discharge pipe 72, realizing the automated separation and recovery of nickel elemental powder. The ultrasonic transducer 70 and the discharge valve 73 adopt existing technologies. For example, the ultrasonic transducer 70 can be a KN3528-45HB type ultrasonic transducer, and the discharge valve 73 can be a QF41F46-50 discharge valve.

[0030] The method of using the active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater in this embodiment includes the following steps: S1. The nickel-containing wastewater from the water tank 40 is extracted by the water pump 31 and transported to the high-pressure atomizing nozzle 30. The liquid wastewater is atomized into fine droplets by the high-pressure atomizing nozzle 30 and sprayed. At this time, the ammonia gas in the liquid ammonia tank 32 is sent into the air inlet 122 after the flow rate is regulated by the liquid ammonia rotor flow meter 320. After being stabilized and divided by the double-layer manifold of the gas distributor 14, it is evenly dispersed in the sealed reaction box 12 through the staggered first jet column 141 and second jet column 143. S2. The dielectric barrier discharge unit 2 is connected to the high and low voltage power supply. The outer mesh ceramic 21 forms a high voltage anode and the inner mesh ceramic 20 forms a micro hollow cathode. Under the barrier effect of the porous polyimide dielectric barrier layer 22, a uniform low-temperature plasma is formed in the micropores. The high-energy electric field ionizes ammonia and water vapor in the mixed system, continuously generating a large number of highly active hydrogen free radicals. There is no large electric arc, and stable micro-discharge is achieved. S3. Atomized nickel-containing wastewater droplets penetrate into the micropores of the sandwich-type DBD structure. The active hydrogen free radicals enriched at the micropore interface react with the Ni in the wastewater. 2+ A directional reduction reaction occurs, reducing nickel ions to elemental nickel. The elemental nickel initially adheres to the surfaces of the inner mesh ceramic 20 and the outer mesh ceramic 21, as well as the inner wall of the sealed reaction chamber 12. S4. After the reaction, the residual ammonia and waste gas are discharged from the drain / gas port 120 into the tail gas treatment tower 8, where they are neutralized and purified by the acidic absorption liquid inside the tower. The online detector 80 at the exhaust end monitors the ammonia concentration in real time. When the concentration exceeds the standard, the electrical control cabinet opens the one-way valve 82 and returns the tail gas to the return pipeline 81 for secondary purification. S5. After the discharge reaction is completed, the ultrasonic transducer 70 on the inner wall of the sealed reaction chamber 12 is activated. The attached nickel powder is shaken off by the ultrasonic cavitation effect. The nickel powder falls into the bottom conical collection hopper 71 under gravity. The discharge valve 73 is opened at regular intervals. The nickel powder is automatically collected into the nickel powder collection tank 74 through the discharge pipe 72, completing the recovery of nickel resources. The residual liquid after the reaction falls back into the connected water tank 40 through the electric valve 41.

Claims

1. An active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater, characterized in that, The device includes a main body (1) with a maintenance cover (10) on the rear side, a dielectric barrier discharge unit (2), a gas-liquid mass transfer unit (3), a waste liquid supply unit (4), and an electrical control cabinet (5) located in the main body (1). The main body of the device (1) has a through-hole (11) at the center of the upper end. A sealed reaction box (12) is movably installed at the through-hole (11). The side wall of the sealed reaction box (12) is provided with a drain / air port (120), a water inlet (121) and an air inlet (122). The dielectric barrier discharge unit (2) includes several inner mesh ceramics (20) arranged in parallel inside a sealed reaction chamber (12), an outer mesh ceramic (21) sleeved on the outer wall of each inner mesh ceramic (20), and a dielectric barrier layer (22) disposed between the outer mesh ceramic (21) and the corresponding inner mesh ceramic (20). The inner mesh ceramic (20) is provided with a cathode, and the outer mesh ceramic (21) is provided with an anode. The cathode and the anode together constitute a high-energy electric field. The gas-liquid mass transfer unit (3) includes a high-pressure atomizing nozzle (30) connected to the water inlet (121), a water pump (31) connected to the high-pressure atomizing nozzle (30), and a liquid ammonia tank (32) connected to the air inlet (122). A liquid ammonia rotor flow meter (320) is provided at the connection between the liquid ammonia tank (32) and the air inlet (122). The waste liquid supply unit (4) includes a water tank (40) connected to the water pump (31) and an electric valve (41) for connecting the water tank (40) to the bottom of the sealed reaction tank (12). The electrical control cabinet (5) is electrically connected to the anode, cathode, water pump (31), liquid ammonia rotor flow meter (320) and electric valve (41).

2. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 1, characterized in that, The dielectric barrier layer (22) is made of porous polyimide film. The mesh diameter of the inner mesh ceramic (20), the outer mesh ceramic (21) and the dielectric barrier layer (22) is 5-8μm. The mesh of the inner mesh ceramic (20) corresponds one-to-one with that of the outer mesh ceramic (21) and the dielectric barrier layer (22).

3. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 1, characterized in that, A gas distributor (14) is connected inside the air inlet (122).

4. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 3, characterized in that, The gas distributor (14) includes a first hollow manifold (140) connected to the interior of the air inlet (122), several first jet columns (141) disposed on one side of the first hollow manifold (140), a second hollow manifold (142) with several through holes (1420) on its sidewall for the first jet columns (141) to pass through, and several second jet columns (143) disposed on the sidewall of the second hollow manifold (142) and staggered with each of the first jet columns (141). Several vent pipes (144) pass between the first hollow manifold (140) and the second hollow manifold (142). Each vent pipe (144) and each of the first jet columns (141) is provided with a solenoid valve (145).

5. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 4, characterized in that, Each of the first jet column (141) and each of the second jet column (143) is connected to a linkage plate (15) at its free end. The linkage plate (15) is provided with a vent (150) at the location corresponding to the first jet column (141) and the second jet column (143). The linkage plate (15) is connected to the inner wall of the sealed reaction chamber (12) by an electric telescopic rod (151). Both the first jet column (141) and the second jet column (143) are folded hoses.

6. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 1, characterized in that, The drain / air outlet (120) is connected to the tail gas treatment tower (8) through a pipeline. The tail gas treatment tower (8) is provided with an acidic absorbent liquid layer for absorbing unreacted ammonia. The exhaust end of the tail gas treatment tower (8) is provided with an online detector (80). The exhaust end and the inlet end of the tail gas treatment tower (8) are connected through a return pipeline (81) and a one-way valve (82) is provided at the connection. The online detector is electrically connected to the electrical control cabinet (5).

7. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 1, characterized in that, The inner mesh ceramic (20) is connected to the corresponding outer mesh ceramic (21) and the dielectric barrier layer (22) by an insulating fastener (23).

8. The active hydrogen radical generator for targeted reduction of nickel ions in electronic wastewater according to claim 1, characterized in that, It also includes a nickel element recovery unit, which includes an ultrasonic transducer (70) disposed on the inner wall of the sealed reaction chamber (12), a conical collection hopper (71) disposed at the bottom of the sealed reaction chamber (12), a discharge pipe (72) connected to the bottom of the conical collection hopper (71), a discharge valve (73) disposed on the discharge pipe (72), and a nickel powder collection tank (74) connected to the end of the discharge pipe (73); the ultrasonic transducer (70) and the discharge valve (73) are electrically connected to the electrical control cabinet (5).

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