A thin liquid film interface reinforced plasma catalytic water treatment device and method

Abstract

This invention provides a plasma catalytic water treatment device and method with enhanced thin-film interface, applicable to the fields of water treatment and advanced oxidation technologies. The device includes a reaction chamber, a guide pipe, conductive components, a catalyst active layer, a gas path system, a water path system, and an electrical system. The liquid to be treated enters through the bottom of the guide pipe and overflows from the top, forming a downward-flowing thin-film on the outer surface of the guide pipe. After the process gas enters the reaction chamber, a plasma discharge zone is formed under the applied voltage of the conductive components. The catalyst active layer on the outer surface of the guide pipe and the active components generated by the plasma synergistically act on the thin-film to inactivate pathogenic microorganisms and degrade organic pollutants. By constructing a thin-film reaction interface close to the discharge zone, this device improves the gas-liquid contact efficiency, discharge energy utilization rate, and liquid-phase oxidation reaction efficiency, making it suitable for wastewater treatment, disinfection and purification, and the removal of recalcitrant organic pollutants.

Description

Technical Field

[0001] This invention relates to the fields of water treatment and advanced oxidation technology, specifically to a plasma catalytic water treatment device and method with thin-film interface enhancement. Background Technology

[0002] With the increasing demand for the treatment of industrial wastewater, domestic sewage, and water bodies containing trace amounts of organic pollutants, treatment technologies that simultaneously inactivate microorganisms and degrade organic pollutants have attracted widespread attention. While existing methods such as chlorination, ultraviolet irradiation, and ozone oxidation have been applied, they still suffer from problems such as byproduct risks, limited treatment efficiency, or high energy consumption. Plasma technology can generate high-energy electrons, ultraviolet radiation, reactive oxygen species, and other forms of energy at room temperature, possessing the potential to simultaneously kill microorganisms and oxidize and degrade pollutants, thus having application value in the field of environmental remediation. However, when traditional plasma directly treats liquids, the ultraviolet light, visible light, and some radiation energy generated by the discharge are difficult for the liquid to fully absorb and utilize, with some energy dissipating as thermal radiation or other forms. Simultaneously, the generation, enrichment, and transfer efficiency of active components in the liquid phase is limited, resulting in unsatisfactory treatment effects against some highly resistant pathogenic microorganisms and recalcitrant organic pollutants when relying solely on plasma.

[0003] Therefore, it is necessary to provide a water treatment device and method that can construct a stable gas-liquid reaction interface, shorten the mass transfer path, and improve the efficiency of discharge transfer to the liquid phase, so as to enhance the overall performance of microbial inactivation and organic pollutant removal. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a plasma catalytic water treatment device and method with thin liquid film interface enhancement, in order to construct a liquid film reaction interface close to the discharge region, enhance gas-liquid two-phase mass transfer and active species utilization efficiency, thereby improving the microbial inactivation effect and promoting the degradation of organic pollutants.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] This invention discloses a plasma catalytic water treatment device with thin liquid film interface enhancement. The device includes: a reaction chamber (1), a guide pipe (2), a conductive component (3), a catalyst active layer (12), a gas path system, a water path system, and a circuit system.

[0007] The guide pipe (2) is disposed in the reaction chamber (1), the bottom of the guide pipe (2) is fixed to the bottom of the reaction chamber (1), the bottom of the guide pipe (2) is provided with an inlet (201), the top of the guide pipe (2) is provided with an outlet (202), and the outer surface of the guide pipe (2) is provided with the catalyst active layer (12).

[0008] The top of the reaction chamber (1) is provided with an air inlet (101), and the bottom of the reaction chamber (1) is provided with an air outlet (102) and a drain outlet (103).

[0009] The conductive component (3) is disposed on the outer wall and / or inner wall of the reaction chamber (1), and the conductive component (3) is connected to the circuit system through a circuit.

[0010] The water system is used to inject wastewater into the guide pipe (2) through the inlet (201), so that the wastewater flows out from the outlet (202) and forms a thin liquid film on the outer surface of the guide pipe (2);

[0011] The gas path system is used to inject process gas into the reaction chamber (1) through the air inlet (101);

[0012] The circuit system is used to apply voltage to the conductive component (3), so that the conductive component (3) discharges and breaks down the process gas to generate low-temperature plasma and tail gas, so as to use the low-temperature plasma and the catalyst active layer (12) to kill pathogenic microorganisms and degrade organic matter on the thin liquid film to obtain treated wastewater, and discharge the treated wastewater through the drain outlet (103) and discharge the tail gas through the gas outlet (102).

[0013] Optionally, the gas system includes: an air inlet chamber (4), a gas storage cylinder (8), and an air pump (9);

[0014] The air pump (9) is connected to the gas storage cylinder (8) and the air inlet chamber (4) through a pipeline, and is used to input the process gas stored in the gas storage cylinder (8) into the air inlet chamber (4).

[0015] The air inlet chamber (4) is located at the top of the reaction chamber (1). The air inlet chamber (4) is connected to the reaction chamber (1) through the air inlet (101) and is used to uniformly inject the process gas into the reaction chamber (1) through the air inlet (101).

[0016] Optionally, the water system includes: a water pump (6), a water storage tank (7), and a filter device (14).

[0017] The water pump (6) is connected to the water storage tank (7) through a pipe. The filter device (14) is located at the water inlet (201). The water pump (6) is connected to the water inlet (201) through a pipe and is used to filter the wastewater in the water storage tank (7) through the filter device (14) and then inject it into the guide pipe (2).

[0018] Optionally, the drain outlet (103) is connected to the water storage tank (7) via a pipe;

[0019] The water storage tank (7) is also used to collect the treated wastewater discharged through the drain outlet (103), so that the water pump (6) circulates the treated wastewater through the filter device (14) for filtration and then injects it into the guide pipe (2).

[0020] Optionally, the circuit system includes: a high-voltage AC power supply (10);

[0021] The high-voltage AC power supply (10) is connected to the conductive component (3) via a circuit and is used to apply voltage to the conductive component (3).

[0022] Optionally, the circuit system may also include: an oscilloscope (11);

[0023] The oscilloscope (11) is connected to the high-voltage AC power supply (10) via a circuit to monitor and display the voltage value and frequency of the voltage applied by the high-voltage AC power supply (10) to the conductive component (3).

[0024] Optionally, the device further includes: an exhaust chamber (5);

[0025] The exhaust chamber (5) is located at the bottom of the reaction chamber (1). The exhaust chamber (5) is connected to the reaction chamber (1) through the exhaust port (102) and is used to collect the exhaust gas discharged through the exhaust port (102).

[0026] Optionally, the device further includes: an ultrasonic descaling device (13);

[0027] The ultrasonic descaling device (13) is located at the drain outlet (103) and is used to generate ultrasonic vibrations to remove scale deposits at the drain outlet (103).

[0028] Optionally, the catalyst active layer (12) is made of a graphite-phase carbon nitride supported nano-zero-valent iron composite material.

[0029] A second aspect of this invention discloses a plasma-catalyzed water treatment method with enhanced thin-film interface, applied to any of the apparatuses described in the first aspect of this invention, the method comprising:

[0030] The water system injects wastewater into the guide pipe (2) through the inlet (201), so that the wastewater flows out from the outlet (202) and forms a thin liquid film on the outer surface of the guide pipe (2);

[0031] The gas system injects process gas into the reaction chamber (1) through the gas inlet (101);

[0032] The circuit system applies voltage to the conductive component (3), causing the conductive component (3) to discharge and break down the process gas to generate low-temperature plasma and exhaust gas, and the exhaust gas is discharged through the outlet (102);

[0033] The thin liquid membrane is subjected to pathogenic microorganism elimination and organic matter degradation treatment using the low-temperature plasma and the catalyst active layer to obtain treated wastewater;

[0034] The treated wastewater is discharged through the drain outlet (103).

[0035] Based on the above embodiments of the present invention, a plasma catalytic water treatment device and method with enhanced thin liquid film interface is provided. In this scheme, a hollow guide tube is set in the reaction chamber. Wastewater enters from the bottom of the guide tube and overflows from the top, forming a thin liquid film along the outer wall of the guide tube. Process gas is injected into the reaction chamber to form a reaction structure in which the gas and liquid phases are in full contact. This allows the low-temperature plasma generated by the discharge breakdown of the process gas by the conductive components on the inner and / or outer walls of the reaction chamber to directly act on pathogenic microorganisms in the thin liquid film. This, in conjunction with the catalyst active layer on the outer wall of the guide tube, improves the killing efficiency of pathogenic microorganisms and promotes the degradation of organic pollutants. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 This is a structural diagram of a plasma catalytic water treatment device with thin liquid film interface enhancement disclosed in an embodiment of the present invention;

[0038] Figure 2 This is a flowchart of a plasma catalytic water treatment method with thin liquid film interface enhancement disclosed in an embodiment of the present invention;

[0039] Among them, 1 is the reaction chamber, 101 is the air inlet, 102 is the air outlet, 103 is the drain outlet, 2 is the guide pipe, 201 is the water inlet, 202 is the water outlet, 3 is the conductive component, 4 is the air inlet chamber, 5 is the air outlet chamber, 6 is the water pump, 7 is the water storage tank, 8 is the gas storage bottle, 9 is the air pump, 10 is the high-voltage AC power supply, 11 is the oscilloscope, 12 is the catalyst active layer, 13 is the ultrasonic descaling device, and 14 is the filtration device. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] As the background technology indicates, low-temperature plasma alone suffers from low energy utilization efficiency when used for water pollutant treatment: the large amount of ultraviolet and visible light generated during the discharge process is difficult for water to fully absorb and utilize, and some energy is dissipated in the form of ultrasound and thermal radiation. Furthermore, the rate at which plasma directly generates active components (such as ·OH and O3) in water is limited, resulting in insufficient effectiveness of plasma alone against certain resistant pathogenic microorganisms and recalcitrant organic pollutants. Therefore, improving the killing effect on pathogenic microorganisms and promoting the degradation of organic pollutants are urgent problems that need to be solved.

[0043] Therefore, this invention discloses a plasma catalytic water treatment device and method with thin liquid film interface enhancement. In this scheme, a hollow guide tube is set in the reaction chamber. Wastewater enters from the bottom of the guide tube and overflows from the top, forming a thin liquid film along the outer wall of the guide tube. Process gas is injected into the reaction chamber to form a reaction structure in which the gas and liquid phases are in full contact. This allows the low-temperature plasma generated by the discharge breakdown of the process gas by the conductive components on the inner and / or outer walls of the reaction chamber to directly act on the pathogenic microorganisms in the thin liquid film. This, in conjunction with the catalyst active layer on the outer wall of the guide tube, improves the killing efficiency of pathogenic microorganisms and promotes the degradation of organic pollutants.

[0044] like Figure 1 The diagram shown is a structural diagram of a plasma catalytic water treatment device with thin liquid film interface enhancement disclosed in an embodiment of the present invention. The device includes: a reaction chamber 1, a guide pipe 2, a conductive component 3, a catalyst active layer 12, a gas path system, a water path system, and an electrical system.

[0045] The guide pipe 2 is installed in the reaction chamber 1. The bottom of the guide pipe 2 is fixed to the bottom of the reaction chamber 1. The bottom of the guide pipe 2 is provided with an inlet 201 and the top of the guide pipe 2 is provided with an outlet 202. The outer surface of the guide pipe 2 is provided with a catalyst active layer 12.

[0046] An air inlet 101 is provided at the top of the reaction chamber 1, and an air outlet 102 and a drain outlet 103 are provided at the bottom of the reaction chamber 1.

[0047] The conductive component 3 is disposed on the outer wall and / or inner wall of the reaction chamber 1, and the conductive component 3 is connected to the circuit system through a circuit.

[0048] The water system is used to inject wastewater through the inlet 201 into the guide pipe 2, so that the wastewater flows out from the outlet 202 and forms a thin liquid film on the outer surface of the guide pipe 2.

[0049] A gas supply system is used to inject process gas into the reaction chamber 1 through the air inlet 101;

[0050] The circuit system is used to apply voltage to the conductive component 3, so that the conductive component 3 discharges and breaks down the process gas to generate low-temperature plasma and exhaust gas. The low-temperature plasma and the catalyst active layer 12 are used to kill pathogenic microorganisms and degrade organic matter on the thin liquid film to obtain treated wastewater. The treated wastewater is discharged through the drain outlet 103 and the exhaust gas is discharged through the gas outlet 102.

[0051] The reaction chamber 1 (preferably a dielectric barrier discharge reactor) is equipped with a hollow guide pipe 2. Wastewater enters the interior of the guide pipe 2 from the inlet 201 at the bottom and overflows from the outlet 202 at the top, forming a thin liquid film that flows downward along the outer wall of the guide pipe 2. This film comes into full contact with the gas phase discharge zone in the reaction chamber 1, forming a reaction structure in which the gas and liquid phases are in full contact. This allows the low-temperature plasma to act directly on the thin liquid film, avoiding the problem that the large amount of ultraviolet and visible light generated during the existing low-temperature plasma discharge process is difficult for the wastewater to fully absorb and utilize, and that some of the energy is dissipated in the form of ultrasonic waves and thermal radiation.

[0052] It should be noted that the low-temperature plasma discharge process is carried out in the reaction chamber 1, so that the low-temperature plasma directly acts on the thin liquid film. That is, the ultrasonic waves, ultraviolet rays and radiation energy generated during the low-temperature plasma discharge process are fully absorbed by the wastewater, generating active substances such as ozone, hydrogen peroxide and hydroxyl radicals. The catalyst active layer 12 further catalytically decomposes the ozone, hydrogen peroxide and other oxidants generated by the plasma to generate hydroxyl radicals with stronger oxidizing properties, thereby realizing the synergistic sterilization and disinfection of wastewater and degradation of organic pollutants by low-temperature plasma and catalyst.

[0053] In this embodiment of the invention, combining low-temperature plasma technology with a supported catalyst, and adding a reaction structure for full gas-liquid two-phase contact and an ozone recycling system, can significantly improve the inactivation efficiency of bacteria and viruses in wastewater. The thin liquid film falling from the outer wall of the guide tube forms a stable gas-liquid two-phase interface, allowing the wastewater to fully absorb and utilize the ultrasonic, ultraviolet, and radiation energy generated during plasma discharge. The generated active substances can accumulate at the interface and efficiently transfer mass to the liquid phase. Combined with the catalyst, this significantly improves the killing rate of microorganisms in the wastewater. After introducing the catalyst, the killing rate of indicator bacteria such as Escherichia coli by low-temperature plasma is significantly improved. Under the same discharge time, the number of viable bacteria remaining in the wastewater is far lower than the level when no catalyst is used, thus greatly enhancing the sterilization effect.

[0054] Furthermore, this invention also possesses advanced oxidation capabilities while disinfecting. The synergistic effect of the active substances generated by plasma and the catalyst can degrade recalcitrant organic compounds such as antibiotics, reducing the residue of trace pollutants in the disinfected water. This design solves the problem of energy waste and low degradation efficiency caused by the inability of existing low-temperature plasma devices to directly utilize ultrasonic, ultraviolet, and radiation energy for pollutant degradation during wastewater treatment.

[0055] It should also be noted that the embodiments of the present invention employ a thin-film discharge design, combined with the capture and utilization of byproducts by a catalyst, which can significantly reduce the unit disinfection energy consumption. Because the thin-film formed on the outer wall of the guide tube provides a large specific surface area and a short mass transfer path, byproducts such as ozone, hydrogen peroxide, hydroxyl radicals, and ultraviolet radiation generated during the low-temperature plasma discharge process are no longer wasted, but are fully absorbed by the thin-film and combined with the catalyst to drive chemical oxidation reactions. Through the above combined effects, the same or even better treatment effect can be achieved at a lower discharge voltage / power, demonstrating good environmental friendliness and application prospects.

[0056] Preferably, peroxymonosulfate oxidant is pre-added to the wastewater entering the guide pipe 2 to synergistically generate sulfate free radicals during plasma discharge for further degradation of organic pollutants.

[0057] Specifically, the gas system includes: an air inlet chamber 4, a gas storage cylinder 8, and an air pump 9;

[0058] The gas pump 9 is connected to the gas storage cylinder 8 and the gas inlet chamber 4 through a pipeline, and is used to input the process gas stored in the gas storage cylinder 8 into the gas inlet chamber 4. The gas inlet chamber 4 is located at the top of the reaction chamber 1, and the gas inlet chamber 4 is connected to the reaction chamber 1 through the gas inlet 101, and is used to inject the process gas evenly into the reaction chamber 1 through the gas inlet 101.

[0059] The air pump 9 is used to input the process gas stored in the gas storage cylinder 8 into the air inlet chamber 4 after adjusting the flow rate and pressure. The process gas can be air.

[0060] In this embodiment of the invention, the process gas flows sequentially as follows: gas storage cylinder 8, gas pump 9, gas inlet chamber 4, gas inlet 101 and reaction chamber 1. The process gas injected into the reaction chamber 1 flows from top to bottom. When the process gas passes through the area surrounded by the conductive component 3, it will generate low-temperature plasma and exhaust gas under the action of the high voltage generated by the conductive component 3. The exhaust gas is discharged through the gas outlet 102.

[0061] In one embodiment, the device further includes: an exhaust chamber 5; the exhaust chamber 5 is disposed at the bottom of the reaction chamber 1, and the exhaust chamber 5 is connected to the reaction chamber 1 through an exhaust port 102, for collecting the exhaust gas discharged through the exhaust port 102.

[0062] Among them, the exhaust chamber 5 also has a pressure stabilizing function.

[0063] Specifically, the water system includes: a water pump 6, a water storage tank 7, and a filter device 14; the water pump 6 is connected to the water storage tank 7 through a pipe, and the filter device 14 is installed at the water inlet 201. The water pump 6 is connected to the water inlet 201 through a pipe and is used to filter the wastewater in the water storage tank 7 through the filter device 14 and then inject it into the guide pipe 2.

[0064] In this embodiment of the invention, the wastewater flows sequentially as follows: water storage tank 7, water pump 6, filter device 14, inlet 201, guide pipe 2, outlet 202, catalyst active layer 12, and drain 103. The outlet 202 acts as a flow equalizer; wastewater overflowing from the outlet 202 forms a uniform thin liquid film on the outside of the guide pipe 2, where the catalyst active layer 12 is located. Through this structural design, the wastewater falls as a thin liquid film on the outer wall of the guide pipe, fully contacting the gas-phase plasma discharge region, achieving efficient mass transfer and extensive contact between the gas and liquid phases, thereby synergistically enhancing sterilization through catalysis while simultaneously degrading pollutants.

[0065] The filter device 14 is a washable filter screen or filter cartridge installed at the front end of the inlet 201, used to intercept particulate impurities in the wastewater and prevent impurities from entering the guide pipe 2.

[0066] It should be noted that the filtration device 14 can remove particulate suspended solids entrained in the wastewater, preventing solid impurities from depositing on the inner or outer wall of the guide pipe 2 or the bottom of the reaction chamber 1, thus affecting the formation of the thin liquid film or the activity of the catalyst active layer 12. Simultaneously, the filtration pretreatment ensures the stable operation of the subsequent low-temperature plasma discharge process, improving the reliability and service life of the device when treating wastewater containing suspended impurities.

[0067] In one embodiment, the drain outlet 103 is connected to the water storage tank 7 via a pipe; the water storage tank 7 is also used to collect the treated wastewater discharged through the drain outlet 103, so that the water pump 6 circulates the treated wastewater through the filter device 14 for filtration and then injects it into the guide pipe 2.

[0068] It should be noted that the water pump 6, water storage tank 7, filter device 14 and the pipelines between them constitute a circulating water circuit, realizing the recycling of wastewater and the efficient utilization of residual oxidants in the wastewater (such as active substances such as hydroxyl radicals; if peroxymonosulfate oxidant is added to the wastewater in advance, the residual oxidant contains sulfate radicals), avoiding waste of reagents; after being treated by the device, the wastewater is recycled back for repeated treatment to improve the disinfection and degradation effect.

[0069] Specifically, the circuit system includes: a high-voltage AC power supply 10; the high-voltage AC power supply 10 is connected to the conductive component 3 through a circuit and is used to apply voltage to the conductive component 3.

[0070] Preferably, the conductive component 3 is a metal mesh electrode arranged around the outer wall of the reaction chamber 1. The conductive component 3 is connected to the high-voltage AC power supply 10 after being isolated by a dielectric barrier layer. The peak voltage of the high-voltage AC power supply 10 is 10-13kV and the frequency is 5-10kHz, so as to generate a uniform and stable low-temperature plasma discharge process.

[0071] In one embodiment, the circuit system further includes an oscilloscope 11; the oscilloscope 11 is connected to the high-voltage AC power supply 10 via a circuit and is used to monitor and display parameters such as the voltage value and frequency of the voltage applied by the high-voltage AC power supply 10 to the conductive component 3.

[0072] In one embodiment, the apparatus further includes an ultrasonic descaling device 13; the ultrasonic descaling device 13 is disposed at the drain outlet 103 and is used to generate ultrasonic vibrations to remove scale deposits at the drain outlet 103.

[0073] Preferably, the ultrasonic descaling device 13 is disposed at the drain outlet 103 or on the outer wall of the water outlet passage connected thereto, and an elastic vibration isolator is provided between the ultrasonic descaling device 13 and the drain outlet 103 or the outer wall of the water outlet passage to reduce structural sound transmission coupling. The ultrasonic descaling device 13 is a surface-mount transducer, which is bonded to the drain outlet 103 or the outer wall of the water outlet passage by sound-conducting adhesive (elastic vibration isolator), and its operating frequency is 20–40 kHz, used to inhibit the formation of carbonate scale.

[0074] The ultrasonic descaling device 13 added in this embodiment of the invention can effectively prevent scale from depositing at the water outlet channel and drain outlet 103 of the reaction chamber 1, thereby avoiding performance degradation or frequent shutdowns for cleaning due to scale buildup, and improving the stability and maintenance convenience of the device during long-term continuous operation.

[0075] Preferably, the catalyst active layer 12 is a nano-zero-valent iron composite material (Fe / g-C3N4) supported on graphitic carbon nitride. In this catalyst, the active component of zero-valent iron provides Fenton-like reaction sites under the influence of ultraviolet light and hydrogen peroxide generated by plasma discharge, rapidly producing hydroxyl radicals. Graphitic carbon nitride, acting as a support, on the one hand, prevents the agglomeration of nano-iron particles and provides a large specific surface area; on the other hand, its own reducing properties facilitate the recycling and regeneration of the zero-valent iron's activity. Therefore, in a low-temperature plasma discharge environment, the above-mentioned composite catalyst can be efficiently activated, continuously generating large amounts of strong oxidizing substances such as ·OH, O3, and H2O2, and synergistically working with the direct discharge effect to achieve more efficient sterilization, disinfection, and pollutant degradation of the target wastewater.

[0076] The process of setting the catalyst active layer 12 on the outer surface of the guide pipe 2 is as follows: the outer wall of the guide pipe 2 is pre-coated with a layer of Fe / g-C3N4 catalyst slurry and dried and fixed to form a catalyst active layer 12 with a thickness of about 0.5mm. This active layer 12 works together with the active substances (hydrogen peroxide, ozone, hydroxyl radicals, etc.) generated by low-temperature plasma to achieve efficient killing of microorganisms and degradation of organic matter in wastewater.

[0077] To verify the effectiveness of graphitic carbon nitride-supported nano-zero-valent iron composite material as the catalyst active layer 12, the following verification examples are provided:

[0078] A certain amount of melamine was calcined in an inert atmosphere to generate graphitic carbon nitride. Then, under stirring, the graphitic carbon nitride was dispersed in an ethanol-water mixture with ferrous sulfate added, followed by the addition of sodium borohydride as a reducing agent, causing nano-zero-valent iron to be deposited in situ on the surface of the graphitic carbon nitride. After washing and drying, Fe / g-C3N4 composite powder catalyst was obtained. The prepared Fe / g-C3N4 (Verification Example 1), single nano-zero-valent iron (Comparative Example 1), and single graphitic carbon nitride (Comparative Example 2) were respectively loaded onto the outer wall of a flow guide tube (catalyst dosage approximately 50 mg / L wastewater). The proportion of the water sample to be treated was coated onto the outside of the flow guide tube. The inlet water of the device was a solution of E. coli with a concentration of 10¹⁰ CFU / L. After 2 minutes of low-temperature plasma discharge, the viable bacteria were counted using the plate coating method. The results are shown in the table below.

[0079]

[0080] The results showed that Example 1 had the best sterilization effect, with only 0.005063% of viable bacteria remaining after 2 minutes. Compared with the comparative example of 0.1526%, the addition of catalyst in Example 1 resulted in the inactivation of an additional 96.7% of E. coli, improving sterilization efficiency by 1.479 orders of magnitude.

[0081] To verify the effectiveness of the thin-film interface-enhanced plasma catalytic water treatment device disclosed in the above embodiments of the present invention, the following application examples for the treatment of tetracycline-containing wastewater are provided.

[0082] Application Example 1: Prepare 1L of solution with a concentration of 10 mg·L⁻¹ -1 The tetracycline solution was ultrasonically mixed for 10 minutes to ensure uniform distribution of tetracycline in the solution. Then, the prepared tetracycline solution was poured into the water tank 7, and the water pump 6 was turned on to allow the tetracycline solution to flow at a rate of 1.25 L / min. -1 The flow rate circulation is as follows: water flows from inlet 201 into guide pipe 2 via pump 6, filling the guide pipe 2 from bottom to top, and then flows back down to the bottom of reaction chamber 1 via outlet 202. Air (process gas) is introduced through gas cylinder 8, and the air discharge is adjusted to 1 standard liter per minute using a mass flow controller. Conductive component 3 is energized, and at the start of discharge, the peak voltage and frequency of high-voltage AC power supply 10 are set to 10kV and 9.2kHz, respectively. The gas in reaction chamber 1 generates low-temperature plasma through dielectric barrier discharge. The low-temperature plasma degrades organic pollutants in the liquid to be treated. The remaining gas and treated liquid in reaction chamber 1 enter water storage tank 7 through outlet 102 and drain 103, respectively, to achieve circulation. Samples are taken from water storage tank 7 every 5 minutes to determine and record the tetracycline concentration in the solution.

[0083] Application Example 2: Except that the peak voltage of the AC power supply is set to 11kV at the start of discharge, the rest is the same as in Application Example 1.

[0084] Application Example 3: Except that the peak voltage of the AC power supply is set to 12kV at the start of discharge, the rest is the same as Application Example 1.

[0085] Application Example 4: Except that the peak voltage of the AC power supply is set to 13kV at the start of discharge, the rest is the same as Application Example 1.

[0086] The tetracycline concentration data collected in Application Examples 1 to 4 were statistically analyzed, and the results are shown in the table below:

[0087]

[0088] The tetracycline concentrations after 10 minutes of cyclic treatment in Application Examples 1 to 4 were all much lower than the initial tetracycline concentration, indicating that the device of the present invention can remove and degrade organic pollutants in tetracycline solution in a highly efficient and low-energy-consumption manner, thus ensuring the removal effect of organic pollutants.

[0089] When the input voltage increased from 10 kV to 13 kV, the concentration of tetracycline after 10 min of cyclic treatment increased from 3.41 mg·L⁻¹. -1Significantly reduced to 0.82 mg·L -1 However, no further significant decrease in tetracycline concentration was observed after further increasing the input voltage. This is because, in this invention, charge accumulates on the dielectric plate, and upon reaching a threshold, it breaks through the air to form plasma. Excited particles such as high-energy electrons in the plasma return to the ground state, generating free radicals such as hydroxyl radicals and long-lived active substances such as hydrogen peroxide and ozone. In this process, higher voltages will generate more active substances. In the aqueous phase, the ultrasonic waves, ultraviolet rays, and thermal radiation generated by the plasma are also utilized, generating more hydroxyl radicals that participate in the degradation of tetracycline. Therefore, a high input voltage within a certain range helps to accelerate the degradation of organic pollutants in solution, but the performance gain tends to be limited as the voltage continues to increase. A trade-off was made between economic cost and degradation performance, and Application Example 1 is the most preferred embodiment of this invention.

[0090] Based on the thin-film interface enhanced plasma catalytic water treatment device disclosed in the above embodiments of the present invention, a hollow guide tube is provided in the reaction chamber. Wastewater enters from the bottom of the guide tube and overflows from the top, forming a thin-film along the outer wall of the guide tube. Process gas is injected into the reaction chamber to form a reaction structure in which the gas and liquid phases are in full contact. This allows the low-temperature plasma generated by the discharge breakdown of the process gas by the conductive components on the inner and / or outer walls of the reaction chamber to directly act on pathogenic microorganisms in the thin-film, and to improve the killing efficiency of pathogenic microorganisms in conjunction with the catalyst active layer on the outer wall of the guide tube, and to promote the degradation of organic pollutants.

[0091] Based on the above embodiments of the present invention, a plasma catalytic water treatment device with enhanced thin-film interface is disclosed, such as... Figure 2 The diagram shows a flowchart of a thin-film interface-enhanced plasma catalytic water treatment method disclosed in an embodiment of the present invention. This method is applied to any of the thin-film interface-enhanced plasma catalytic water treatment devices disclosed in the above embodiments of the present invention and includes the following steps:

[0092] Step S201: Wastewater is injected into the water system through the inlet guide pipe, so that the wastewater flows out from the outlet and forms a thin liquid film on the outer surface of the guide pipe.

[0093] Step S202: The gas system injects process gas into the reaction chamber through the gas inlet.

[0094] Step S203: The circuit system applies voltage to the conductive component, causing the conductive component to discharge and break down the low-temperature plasma and exhaust gas generated by the process gas, and then discharge the exhaust gas through the outlet.

[0095] Step S204: Using low-temperature plasma and a catalyst active layer, the thin liquid membrane is subjected to pathogenic microorganism elimination and organic matter degradation treatment to obtain treated wastewater.

[0096] Step S205: Discharge the treated wastewater through the drain outlet.

[0097] For detailed explanations, please refer to the above embodiments of the present invention, which will not be repeated here.

[0098] Based on the above-described embodiment of the present invention, a plasma catalytic water treatment method with thin liquid film interface enhancement is disclosed. In this scheme, a hollow guide tube is set in the reaction chamber. Wastewater enters from the bottom of the guide tube and overflows from the top, forming a thin liquid film along the outer wall of the guide tube. Process gas is injected into the reaction chamber to form a reaction structure in which the gas and liquid phases are in full contact. This allows the low-temperature plasma generated by the discharge breakdown of the process gas by the conductive components on the inner and / or outer walls of the reaction chamber to directly act on pathogenic microorganisms in the thin liquid film. This, in conjunction with the catalyst active layer on the outer wall of the guide tube, improves the killing efficiency of pathogenic microorganisms and promotes the degradation of organic pollutants.

[0099] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0100] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0101] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plasma catalytic water treatment device with thin-film interface enhancement, characterized in that, The device includes: a reaction chamber (1), a guide pipe (2), a conductive component (3), a catalyst active layer (12), a gas path system, a water path system, and an electrical system; The guide pipe (2) is disposed in the reaction chamber (1), the bottom of the guide pipe (2) is fixed to the bottom of the reaction chamber (1), the bottom of the guide pipe (2) is provided with an inlet (201), the top of the guide pipe (2) is provided with an outlet (202), and the outer surface of the guide pipe (2) is provided with the catalyst active layer (12). The top of the reaction chamber (1) is provided with an air inlet (101), and the bottom of the reaction chamber (1) is provided with an air outlet (102) and a drain outlet (103). The conductive component (3) is disposed on the outer wall and / or inner wall of the reaction chamber (1), and the conductive component (3) is connected to the circuit system through a circuit. The water system is used to inject wastewater into the guide pipe (2) through the inlet (201), so that the wastewater flows out from the outlet (202) and forms a thin liquid film on the outer surface of the guide pipe (2); The gas path system is used to inject process gas into the reaction chamber (1) through the air inlet (101); The circuit system is used to apply voltage to the conductive component (3), so that the conductive component (3) discharges and breaks down the process gas to generate low-temperature plasma and tail gas, so as to use the low-temperature plasma and the catalyst active layer (12) to kill pathogenic microorganisms and degrade organic matter on the thin liquid film to obtain treated wastewater, and discharge the treated wastewater through the drain outlet (103) and discharge the tail gas through the gas outlet (102).

2. The apparatus according to claim 1, characterized in that, The gas system includes: an air inlet chamber (4), a gas storage cylinder (8), and an air pump (9); The air pump (9) is connected to the gas storage cylinder (8) and the air inlet chamber (4) through a pipeline, and is used to input the process gas stored in the gas storage cylinder (8) into the air inlet chamber (4). The air inlet chamber (4) is located at the top of the reaction chamber (1). The air inlet chamber (4) is connected to the reaction chamber (1) through the air inlet (101) and is used to uniformly inject the process gas into the reaction chamber (1) through the air inlet (101).

3. The apparatus according to claim 1, characterized in that, The water system includes: a water pump (6), a water storage tank (7), and a filter device (14). The water pump (6) is connected to the water storage tank (7) through a pipe. The filter device (14) is located at the water inlet (201). The water pump (6) is connected to the water inlet (201) through a pipe and is used to filter the wastewater in the water storage tank (7) through the filter device (14) and then inject it into the guide pipe (2).

4. The apparatus according to claim 3, characterized in that, The drain outlet (103) is connected to the water storage tank (7) via a pipe; The water storage tank (7) is also used to collect the treated wastewater discharged through the drain outlet (103), so that the water pump (6) circulates the treated wastewater through the filter device (14) for filtration and then injects it into the guide pipe (2).

5. The apparatus according to claim 1, characterized in that, The circuit system includes: a high-voltage AC power supply (10). The high-voltage AC power supply (10) is connected to the conductive component (3) via a circuit and is used to apply voltage to the conductive component (3).

6. The apparatus according to claim 5, characterized in that, The circuit system also includes: an oscilloscope (11); The oscilloscope (11) is connected to the high-voltage AC power supply (10) via a circuit to monitor and display the voltage value and frequency of the voltage applied by the high-voltage AC power supply (10) to the conductive component (3).

7. The apparatus according to claim 1, characterized in that, The device further includes: an air outlet chamber (5); The exhaust chamber (5) is located at the bottom of the reaction chamber (1). The exhaust chamber (5) is connected to the reaction chamber (1) through the exhaust port (102) and is used to collect the exhaust gas discharged through the exhaust port (102).

8. The apparatus according to claim 1, characterized in that, The device also includes: an ultrasonic descaling device (13); The ultrasonic descaling device (13) is located at the drain outlet (103) and is used to generate ultrasonic vibrations to remove scale deposits at the drain outlet (103).

9. The apparatus according to any one of claims 1 to 8, characterized in that, The catalyst active layer (12) is made of a graphite phase carbon nitride supported nano-zero valent iron composite material.

10. A plasma-catalyzed water treatment method with thin-film interface enhancement, characterized in that, Applied to the apparatus of any one of claims 1 to 9, the method comprises: The water system injects wastewater into the guide pipe (2) through the inlet (201), so that the wastewater flows out from the outlet (202) and forms a thin liquid film on the outer surface of the guide pipe (2); The gas system injects process gas into the reaction chamber (1) through the gas inlet (101); The circuit system applies voltage to the conductive component (3), causing the conductive component (3) to discharge and break down the process gas to generate low-temperature plasma and exhaust gas, and the exhaust gas is discharged through the outlet (102); The thin liquid membrane is subjected to pathogenic microorganism elimination and organic matter degradation treatment using the low-temperature plasma and the catalyst active layer to obtain treated wastewater; The treated wastewater is discharged through the drain outlet (103).

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