Coal gasification slag-based composite particle electrode and preparation method thereof, and three-dimensional electrode reaction device

Abstract

The present application belongs to the technical field of wastewater treatment, and discloses a coal gasification slag-based composite particle electrode, a preparation method thereof, and a solar-driven photoelectric synergistic three-dimensional electrode reactor device. The coal gasification slag-based composite particle electrode is obtained by loading nickel oxide and copper oxide active components on coal gasification fine slag as a carrier after activation treatment. The three-dimensional electrode reactor containing the composite particle electrode comprises a reactor shell, an anode plate, a cathode plate, a particle electrode layer, an aeration system, a solar light condensing device, a solar energy supply system, and a power supply, and preferably further comprises a circulating system. The specific surface area and active sites of the carrier are increased through activation treatment, and the synergistic catalysis of nickel oxide and copper oxide is utilized to achieve simultaneous and efficient removal of ammonia nitrogen and humic acid in landfill leachate. The present application utilizes coal gasification solid waste resources in the field of water treatment, and has simple preparation method, stable particle electrode performance, and high treatment efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and relates to a coal gasification slag-based composite particle electrode and its preparation method, as well as a three-dimensional electrode reaction device. Background Technology

[0002] Landfill leachate is a highly concentrated organic wastewater with an extremely complex composition. Ammonia nitrogen and humic acid are two typical and difficult-to-treat pollutants. High concentrations of ammonia nitrogen easily lead to eutrophication of water bodies and damage aquatic ecosystems; while humic acid, as a large-molecule organic compound, is not only difficult to biodegrade itself, but can also complex with heavy metal ions, further increasing the difficulty of treatment. Therefore, achieving the simultaneous and efficient removal of ammonia nitrogen and humic acid from landfill leachate is a key challenge that urgently needs to be solved in the field of water pollution control.

[0003] Three-dimensional electrocatalytic oxidation technology has attracted widespread attention in the treatment of recalcitrant organic wastewater due to its advantages such as high efficiency, cleanliness, ease of operation, and environmental compatibility. This technology significantly increases the reaction surface area and shortens the mass transfer distance by filling the space between traditional two-dimensional electrodes with particle electrodes, thereby substantially improving current efficiency and pollutant degradation rates. The material properties of the particle electrodes are the core determinant of the performance of the three-dimensional electrode system.

[0004] Coal gasification slag is a large amount of solid waste generated in the coal chemical process. Its output is huge, and its storage and disposal not only occupy land, but also pose environmental risks. Coal gasification slag, especially fine coal gasification slag with fine particle size, is rich in silicon, aluminum, carbon and various metal oxides. It has a porous structure and potential catalytic activity, and is a potential low-cost carrier material. However, the research on its direct or simple modification for use as a three-dimensional electrode particle electrode is not yet in-depth. In particular, the development of efficient and stable particle electrodes for the simultaneous removal of ammonia nitrogen and humic acid in landfill leachate still has the following technical gaps: (1) Insufficient utilization of raw material characteristics: Existing technologies have not fully explored the potential contribution of the physical structure (such as specific surface area, pore structure) and chemical composition (such as residual carbon, metal oxides) of coal gasification slag to electrocatalytic performance, and lack targeted activation and modification strategies. (2) Lack of synergistic catalytic design: The removal of ammonia nitrogen mainly depends on the indirect oxidation of ·OH and active chlorine in the electrochemical oxidation process, while the degradation of humic acid depends more on the direct oxidation of ·OH and direct electron transfer on the electrode surface. Most existing particle electrodes use a single active component, which makes it difficult to achieve synergistic and efficient removal of two pollutants with different degradation mechanisms. (3) The loading method of active components needs to be optimized: In the existing technology, the binding force between active components and carriers is weak, and they are easy to fall off during long-term operation, resulting in a decrease in electrode stability, and the dispersibility and utilization rate of active components are not high.

[0005] Therefore, developing a composite particle electrode that can fully utilize the characteristics of coal gasification fine slag, achieve synergistic catalysis through directional modification, and has stable performance, and coupling it with solar energy technology and a photoelectric synergistic three-dimensional electrocatalytic reactor, will have significant social, economic, and environmental benefits for achieving low-energy, high-efficiency deep treatment of landfill leachate and promoting the high-value resource utilization of coal gasification solid waste. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a coal gasification slag-based composite particle electrode and its preparation method. This invention fully exposes the active sites of fine coal gasification slag and regulates its surface properties through a specific sequence of acid-base activation treatments. By loading nickel oxide (NiO) and copper oxide (CuO) as active components, synergistic effects are achieved by utilizing the highly efficient catalytic oxidation performance of NiO for ammonia nitrogen and the excellent electrocatalytic performance of CuO for macromolecular organic compounds such as humic acid. Simultaneously, this invention also provides a photoelectric synergistic three-dimensional electrode reactor device comprising the above-mentioned composite particle electrode and equipped with a solar concentrator and power supply system, to further improve efficiency, reduce operating energy consumption, and enhance the greenness of the process.

[0007] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a coal gasification slag-based composite particle electrode, comprising the following steps: (1) Raw material pretreatment: The coal gasification fine slag is dried, ground and screened, and fine slag powder with a particle size of 0.1-0.5mm is selected as carrier raw material.

[0008] (2) Acid-base activation treatment: (2a) The carrier material obtained in step (1) is placed in a hydrochloric acid solution with a concentration of 0.5-2 mol / L and stirred and soaked at a speed of 300-800 r / min for 20-28 hours at room temperature for acid activation treatment; after the reaction is completed, the mixture is filtered and washed with deionized water until the pH of the filtrate is neutral to obtain the acid-activated carrier.

[0009] (2b) The acid-activated carrier obtained in step (2a) is placed in a sodium hydroxide solution with a concentration of 0.5-2 mol / L and stirred and soaked at a speed of 300-800 r / min for 20-28 hours at room temperature for alkaline activation treatment; after the reaction is completed, the mixture is filtered and washed with deionized water until the pH of the filtrate is neutral, and then dried to obtain the acid-base composite activated carrier.

[0010] (3) Preparation of active component precursors: (3a) Preparation of nickel hydroxide precursor: Nickel chloride hexahydrate (NiCl2·6H2O) was dissolved in deionized water, and sodium hydroxide solution was added dropwise under stirring until the pH was 9-11, a precipitate was formed, and stirring was continued for 0.5-2 hours. The mixture was then allowed to stand for aging, filtered, and washed with deionized water until the pH of the filtrate was neutral. The filtrate was then dried to obtain nickel hydroxide (Ni(OH)2) precursor.

[0011] (3b) Preparation of copper hydroxide precursor: Copper nitrate hexahydrate (Cu(NO3)2·6H2O) was dissolved in deionized water, and sodium hydroxide solution was added dropwise under stirring until the pH was 9-11, a precipitate was formed, and stirring was continued for 0.5-2 hours. The mixture was then allowed to stand for aging, filtered, and washed with deionized water until the pH of the filtrate was neutral. The filtrate was then dried to obtain copper hydroxide (Cu(OH)2) precursor.

[0012] (4) Loading and calcination of active components: (4a) Preparation of nickel oxide-loaded particle electrode: The acid-base composite activation carrier obtained in step (2) and the nickel hydroxide precursor obtained in step (3a) are mixed at a mass ratio of 1:1 to 5:1, and an appropriate amount of deionized water is added. The mixture is ultrasonically treated for 20-60 minutes to ensure thorough dispersion. Subsequently, the mixture is centrifuged at 6000-10000 r / min, the precipitate is collected, and dried at 60-100℃ for 4-12 hours. The dried solid is placed in a muffle furnace and calcined at a heating rate of 2-10℃ / min to 600-800℃ for 1-4 hours to obtain a nickel oxide-loaded coal gasification fine slag-based particle electrode (hereinafter referred to as NiO / GCS).

[0013] (4b) Preparation of copper oxide-loaded particle electrode: The acid-base composite activation carrier obtained in step (2) is mixed with the copper hydroxide precursor obtained in step (3b) at a mass ratio of 1:1 to 5:1. The ultrasonic, centrifugal, drying and calcination operations in step (4a) are repeated to obtain a copper oxide-loaded coal gasification fine slag-based particle electrode (hereinafter referred to as CuO / GCS).

[0014] Preferably, in step (2), the concentration of the hydrochloric acid solution is 1 mol / L, the concentration of the sodium hydroxide solution is 1 mol / L, the stirring speed is 500 r / min, and the soaking time is 24 hours.

[0015] Preferably, in step (4), the mass ratio of the acid-base composite activation carrier to the nickel hydroxide precursor or copper hydroxide precursor is 5:1 or 1:1.

[0016] Preferably, in step (4), the calcination temperature is 700°C and the calcination time is 2 hours.

[0017] In a second aspect, the present invention provides a solar-driven photovoltaic-coordinated three-dimensional electrode reactor device for treating landfill leachate, comprising: The reactor shell has a reaction chamber inside; An anode plate and a cathode plate are disposed in the reaction chamber, and the anode plate and the cathode plate are arranged opposite to each other. A particle electrode layer is filled between the anode plate and the cathode plate, the particle electrode layer comprising the aforementioned coal gasification slag-based composite particle electrode; An aeration system, located at the bottom of the reaction chamber, is used to provide microbubbles to enhance mass transfer and provide oxygen for the cathode reaction; The power supply is electrically connected to the anode plate and the cathode plate, respectively.

[0018] Preferably, the reactor further includes a circulation system, which includes a circulation pump and circulation pipelines for circulating the landfill leachate within the reaction chamber to improve treatment efficiency.

[0019] More preferably, the reactor device further includes a solar concentrator disposed above the reaction chamber to concentrate and direct sunlight over a larger area to the light-transmitting area of ​​the reaction chamber, thereby enhancing the photocatalytic effect.

[0020] More preferably, the reactor device further includes a solar power system comprising photovoltaic panels and a solar tracking device for converting solar energy into electrical energy and providing energy replenishment to the power source or directly powering the electrodes, thereby reducing dependence on the external power grid.

[0021] Thirdly, the present invention provides the application of the coal gasification slag-based composite particle electrode or the three-dimensional electrode reactor in the treatment of landfill leachate containing ammonia nitrogen and humic acid.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses coal gasification fine slag, a solid waste product from coal chemical industry, as raw material. Through activation treatment, it is transformed into a carrier for high-performance particle electrodes, thus preparing a catalytic material with excellent stability and reusability. This achieves high-value utilization of solid waste, turning waste into treasure, and significantly reduces the preparation cost of particle electrodes, thus possessing both environmental and economic benefits.

[0023] (2) In the solar-driven photoelectric coupling system constructed in this invention, composite coal gasification fine slag material is used as particle electrode. With its dual functions of conductivity and light absorption and heat generation, it ensures the high efficiency of electrocatalytic reaction on the one hand, and accelerates the reaction by utilizing photothermal effect on the other hand.

[0024] (3) This invention employs a sequential treatment method of "acid activation + alkali activation". First, acid activation removes some metal oxides and soluble impurities from the surface of the fine slag, clearing the pores. Then, alkali activation further etches the aluminosilicate framework, significantly increasing the specific surface area and surface active functional groups, providing an ideal substrate for the uniform and robust loading of subsequent active components. Compared with single activation or no activation treatment, the acid-alkali composite activated carrier of this invention has a higher specific surface area and more active sites.

[0025] (4) This invention utilizes a stepwise loading strategy to prepare NiO / GCS and CuO / GCS separately, cleverly taking advantage of the selective catalytic properties of the two active components for the target pollutants. Specifically, the loaded nickel oxide efficiently catalyzes the active chlorine generated during electrochemical oxidation, promoting the indirect oxidation reaction of ammonia nitrogen; while copper oxide exhibits excellent electrocatalytic activity and a lower overpotential for macromolecular organic compounds such as humic acid. The stepwise synergistic effect of the two active components enables the composite particle electrode to achieve simultaneous and efficient removal of ammonia nitrogen and humic acid from landfill leachate, with significantly better results than particle electrodes loaded with a single component.

[0026] (5) The three-dimensional electrode reactor designed in this invention organically integrates the solar concentrator and photovoltaic power generation system with the three-dimensional electrocatalytic reactor. On the one hand, it can use light energy to assist in the excitation of photogenerated electron-hole pairs in the catalyst, thereby enhancing the oxidation capacity. On the other hand, it can achieve partial or complete self-sufficiency of electrical energy during periods of sufficient sunshine, which significantly reduces the system's operating energy consumption and carbon emissions, in line with the concept of green and sustainable development. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the three-dimensional electrode reactor in an embodiment of the present invention.

[0033] In the diagram: 1-Reflective concentrator, 2-Light guide tube, 3-Light diffuser, 4, 6-Anode, 5-Cathode, 7-Coal gasification slag-based particle electrode packing, 8-Boost pump, 9-Filter liner, 10-Electric diaphragm valve, 11-DC power supply, 12-Solar photovoltaic panel, 13-Photosensor. Detailed Implementation

[0034] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0035] Example 1 This embodiment provides a coal gasification slag-based composite particle electrode, the preparation method of which is as follows: Step 1: Raw material pretreatment Fine coal gasification residue from a coal chemical enterprise was dried at 105℃ for 24 hours, sealed, and used as a carrier raw material for later use.

[0036] Step 2: Preparation of the composite activation carrier Weigh 5g of the fine residue powder obtained in step 1 and place it in 50mL of 1mol / L hydrochloric acid solution. Stir magnetically at 500r / min at room temperature for 24 hours. After the reaction is complete, filter and wash repeatedly with deionized water until the pH of the filtrate is neutral to obtain the acid-activated carrier.

[0037] The acid-activated carrier was placed in 50 mL of a 1 mol / L sodium hydroxide solution and magnetically stirred at 500 rpm for 24 hours at room temperature. After the reaction was completed, the mixture was filtered and repeatedly washed with deionized water until the pH of the filtrate was neutral. The resulting solid was dried at 105 °C for 12 hours to obtain the acid-base composite activated carrier.

[0038] Step 3: Preparation of active component precursors Preparation of nickel hydroxide precursor: 2.38 g of nickel chloride hexahydrate (NiCl2·6H2O) was dissolved in 20 mL of deionized water. Under vigorous stirring, 1 mol / L sodium hydroxide solution was slowly added dropwise until the pH reached 10, resulting in a blue-green precipitate. After sonication for 20 min, the mixture was allowed to stand for 1 hour. After multiple centrifugations, the solution was washed with deionized water until the pH of the filtrate reached 7, yielding the nickel hydroxide (Ni(OH)2) precursor.

[0039] Preparation of copper hydroxide precursor: Weigh 2.42 g of copper nitrate hexahydrate (Cu(NO3)2·6H2O) and dissolve it in 20 mL of deionized water. Repeat the above operation to obtain copper hydroxide (Cu(OH)2) precursor.

[0040] Step 4: Loading and calcination of active components Preparation of nickel oxide-loaded particle electrode (NiO / GCS): 3.75 g of the acid-base composite activation carrier obtained in step 2 and 0.75 g of the nickel hydroxide precursor obtained in step 3 (mass ratio 5:1) were added to 20 mL of deionized water and ultrasonically treated for 40 minutes in an ultrasonic cleaner. Subsequently, the mixture was centrifuged at 8000 r / min for 10 minutes, the precipitate was collected, and dried at 80 °C for 8 hours. The dried solid was placed in a muffle furnace and calcined at 700 °C at a heating rate of 5 °C / min for 2 hours. After natural cooling, the nickel oxide-loaded coal gasification slag-based particle electrode, denoted as NiO / GCS, was obtained.

[0041] Preparation of copper oxide-loaded particle electrode (CuO / GCS): Take 3.75g of the acid-base composite activation carrier obtained in step 2 and 3.75g of the copper hydroxide precursor obtained in step 3 (mass ratio of 1:1), and repeat the above ultrasonic, centrifugal, drying and calcination operations to obtain a copper oxide-loaded coal gasification slag-based particle electrode, denoted as CuO / GCS.

[0042] Example 2 This embodiment provides a method for preparing a coal gasification slag-based particle electrode for comparing the effects of different activation methods on the performance of the carrier: Step 1: Raw material pretreatment Fine coal gasification residue from a coal chemical enterprise was dried at 105℃ for 24 hours, sealed, and used as a carrier raw material for later use.

[0043] Step 2: Preparation of different activation supports Take three equal portions of the fine powder obtained in step 1, and process them as follows: Acid-activated carrier (H-GCS): Fine slag powder was placed in 50 mL of 1 mol / L hydrochloric acid solution and stirred at 500 r / min for 24 hours at room temperature. After washing and drying, acid-activated particle electrode was obtained, denoted as H-GCS.

[0044] Acid-base composite activated carrier (H-OH-GCS): Following the method in step 2 of Example 1, acid activation was performed first, followed by base activation, to obtain an acid-base composite activated particle electrode, denoted as H-OH-GCS.

[0045] Example 3 This embodiment provides a method for preparing a coal gasification slag-based particle electrode for comparing the effects of different metal oxide active components on pollutant degradation: Step 1: Raw material pretreatment Fine coal gasification residue from a coal chemical enterprise was dried at 105℃ for 24 hours, sealed, and used as a carrier raw material for later use.

[0046] Step 2: Fabrication of particle electrodes supported by different metal oxides Multiple equal portions of the fine slag powder obtained in step 1 were weighed and mixed with equimolar amounts of ferric hydroxide precursor, manganese hydroxide precursor, cobalt hydroxide precursor, nickel hydroxide precursor prepared in Example 1, and copper hydroxide precursor prepared in Example 1. The preparation methods for the ferric hydroxide precursor, manganese hydroxide precursor, and cobalt hydroxide precursor were the same as in step 3 of Example 1, except that the metal salts were replaced with ferric nitrate nonahydrate, manganese chloride tetrahydrate, and cobalt nitrate hexahydrate, respectively. The ultrasonication, centrifugation, drying, and calcination operations in step 4 of Example 1 were repeated for each mixed system to obtain particle electrodes loaded with ferric oxide (Fe2O3 / GCS), manganese oxide (MnO2 / GCS), cobalt oxide (Co3O4 / GCS), nickel oxide (NiO / GCS), and copper oxide (CuO / GCS), respectively.

[0047] Example 4 This embodiment provides a method for preparing a coal gasification slag-based particle electrode for comparing the effects of different loading ratios on pollutant degradation: Step 1: Raw material pretreatment Fine coal gasification residue from a coal chemical enterprise was dried at 105℃ for 24 hours, sealed, and used as a carrier raw material for later use.

[0048] Step 2: Preparation of active component precursor Preparation of nickel hydroxide precursor: 2.38 g of nickel chloride hexahydrate (NiCl2·6H2O) was dissolved in 20 mL of deionized water. Under vigorous stirring, 1 mol / L sodium hydroxide solution was slowly added dropwise until the pH reached 10, resulting in a blue-green precipitate. After sonication for 30 min, the mixture was allowed to stand for 1 hour. After multiple centrifugations, the solution was washed with deionized water until the pH of the filtrate reached 7, yielding the nickel hydroxide (Ni(OH)2) precursor.

[0049] Preparation of copper hydroxide precursor: Weigh 2.42 g of copper nitrate hexahydrate (Cu(NO3)2·6H2O) and dissolve it in 20 mL of deionized water. Repeat the above operation to obtain copper hydroxide (Cu(OH)2) precursor.

[0050] Step 3: Preparation of particle electrodes with different loading ratios Preparation of supported nickel oxide particle electrodes: Multiple equal amounts of the fine slag powder obtained in step 1 were mixed with different masses of nickel hydroxide precursor, such that the mass ratio of support to precursor was 1:1, 3:1, 5:1, and 1:3, respectively. The ultrasonic, centrifugal, drying, and calcination operations in step 4 of Example 1 were repeated for each mixed system to obtain a series of NiO / GCS particle electrodes with different loading ratios.

[0051] Preparation of supported copper oxide particle electrodes: Multiple equal amounts of the fine slag powder obtained in step 1 were mixed with different masses of copper hydroxide precursor, such that the mass ratio of support to precursor was 1:1, 3:1, 5:1, and 1:3, respectively. The ultrasonic, centrifugal, drying, and calcination operations in step 4 of Example 1 were repeated for each mixture system to obtain a series of CuO / GCS particle electrodes with different loading ratios.

[0052] Example 5 This embodiment provides a three-dimensional electrode reactor, such as Figure 1 As shown, the reactor includes a reactor shell with a reaction chamber inside; an anode plate and a cathode plate disposed within the reaction chamber, the anode plate and cathode plate being arranged opposite to each other; a particle electrode layer filling the space between the anode plate and the cathode plate, the particle electrode layer comprising the coal gasification slag-based composite particle electrode prepared in Example 1, namely NiO / GCS and CuO / GCS; an aeration system disposed at the bottom of the reaction chamber for providing microbubbles; and a power supply electrically connected to the anode plate and the cathode plate respectively. Preferably, the reactor further includes a circulation system, the circulation system including a circulation pump and circulation pipelines, for circulating the landfill leachate within the reaction chamber.

[0053] Experimental Example 1: Effects of activation methods on support performance and particle electrode catalytic activity To investigate the effects of different activation methods on the performance of coal gasification slag carriers, this experimental example tested the performance of three activated carriers prepared in Example 2: H-GCS, H-OH-GCS, and unactivated raw slag. Particle electrodes loaded with nickel oxide and copper oxide were prepared using these carriers, and their degradation efficiency for ammonia nitrogen and humic acid was tested.

[0054] Ammonia nitrogen degradation performance test conditions: Prepare an ammonia nitrogen solution with a concentration of 2000 mg / L, use 0.1 mol / L sodium chloride solution as the supporting electrolyte, and determine the ammonia nitrogen removal rate after reacting for a certain period of time under the conditions of voltage 5V, electrode spacing 3cm, electrode area 1cm×1.5cm, particle electrode dosage 2.5g / L.

[0055] Humic acid degradation performance test conditions: Prepare a humic acid solution with a concentration of 2000 mg / L, use 0.1 mol / L sodium chloride solution as the supporting electrolyte, and determine the humic acid removal rate after reacting for a certain period of time under the conditions of voltage of 5V, electrode spacing of 3cm, electrode area of ​​1cm×1.5cm, particle electrode dosage of 2.5g / L.

[0056] Experimental results show that NiO / GCS prepared with H-OH-GCS as the support has the highest removal rate of ammonia nitrogen, while CuO / GCS prepared with H-OH-GCS as the support has the highest removal rate of humic acid, and both are significantly better than particle electrodes prepared with a single activated or unactivated support. This indicates that acid-base combined activation treatment can more effectively open up pores, increase specific surface area and active sites, and provide a better substrate for loading active components.

[0057] Experimental Example 2: Screening experiment of active components of metal oxide To investigate the catalytic activity of different metal oxides in the degradation of ammonia nitrogen and humic acid, this experimental example tested the degradation performance of ammonia nitrogen and humic acid on the particle electrodes prepared in Example 3 that were loaded with different metal oxides (Fe2O3, MnO2, Co3O4, NiO, CuO).

[0058] The test conditions are the same as in Experiment 1.

[0059] For the degradation of ammonia nitrogen, the particle electrode supported on nickel oxide (NiO / GCS) exhibited the best catalytic activity and the highest removal rate; for the degradation of humic acid, the particle electrode supported on copper oxide (CuO / GCS) exhibited the best catalytic activity and the highest removal rate. This indicates that nickel oxide has a highly efficient catalytic effect on the indirect oxidation reaction of ammonia nitrogen (such as the active chlorine pathway), while copper oxide has excellent performance in the direct electro-oxidation of macromolecular organic compounds such as humic acid.

[0060] Experimental Example 3: Experiment on optimization of active component loading ratio To determine the optimal loading of active components, this experimental example tested the degradation performance of ammonia nitrogen and humic acid on a series of NiO / GCS and CuO / GCS particle electrodes with different loading ratios prepared in Example 4.

[0061] The test conditions are the same as in Experiment 1.

[0062] Experimental results show that for the NiO / GCS particle electrode, the removal rate of ammonia nitrogen first increases and then levels off with increasing nickel oxide loading, reaching its optimal level when the mass ratio of support to precursor is 5:1. For the CuO / GCS particle electrode, the removal rate of humic acid reaches its highest level when the mass ratio of support to precursor is 1:1, and further increasing the loading has no significant effect on performance improvement.

[0063] Comparative sample E (supported nickel oxide): same as the NiO / activated fine slag precursor in Example 1.

[0064] Comparative sample F (supported copper oxide): same as CuO / activated fine slag precursor in Example 1.

[0065] The aforementioned single-loaded particle electrodes were filled into a three-dimensional electrode reactor, and the test conditions were the same as in Example 2.

[0066] The results showed that nickel oxide loading (comparative sample E) was the most effective for ammonia nitrogen degradation, achieving a removal rate of 88.5%; while copper oxide loading (comparative sample F) was the most effective for humic acid degradation, achieving a removal rate of 79.3%. The composite particle electrode GCS-1 of Example 1 of this invention, by simultaneously loading nickel oxide and copper oxide, achieved simultaneous and efficient removal of both ammonia nitrogen (92.5%) and humic acid (82.6%), with removal rates superior to any single-loaded particle electrode, demonstrating a significant synergistic effect.

[0067] Experiment Example 4: To investigate the catalytic activity of light irradiation on the degradation of ammonia nitrogen and humic acid, this experimental example tested the degradation performance of ammonia nitrogen and humic acid on the NiO / GCS particle electrode and CuO / GCS particle electrode prepared in Example 3, respectively.

[0068] The test conditions are the same as in Experiment 1.

[0069] The results showed that Group A achieved removal rates of 84.3% for ammonia nitrogen and 71.5% for humic acid; while Group B, under the synergistic effect of solar energy, saw its removal rates of ammonia nitrogen and humic acid increase to 94.1% and 83.7%, respectively, while the overall power consumption of the system decreased by approximately 28%. This indicates that the light energy introduced by solar concentrators not only stimulated the photocatalytic activity of residual carbon and metal oxides in the particle electrodes, promoting the generation of reactive oxygen species, but also that the solar power supply system effectively shared the operating load, achieving the goal of efficient and low-consumption wastewater treatment.

[0070] In summary, the coal gasification slag-based composite particle electrode and its preparation method provided by this invention, along with the three-dimensional electrode reactor device integrating solar energy drive and photoelectric synergy, successfully prepared a composite particle electrode capable of efficiently and stably treating ammonia nitrogen and humic acid simultaneously in landfill leachate through innovative acid-base composite activation and selective loading of NiO and CuO. This particle electrode, combined with the matching three-dimensional electrode reactor, exhibits excellent performance and stability when treating actual landfill leachate, realizing the high-value resource utilization of solid waste and demonstrating significant technological advancement and broad application prospects.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various improvements and modifications without departing from the spirit and principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a coal gasification slag-based composite particle electrode, characterized in that, Includes the following steps: Step 1: Dry and screen the coal gasification slag to obtain the carrier raw material; Step 2: The carrier raw material obtained in Step 1 is subjected to acid activation treatment and alkali activation treatment in sequence, and then washed and dried to obtain a composite activated carrier; Step 3: Prepare nickel hydroxide precursor and copper hydroxide precursor respectively; Step 4: The composite activated carrier obtained in Step 2 is mixed with the nickel hydroxide precursor obtained in Step 3 at a first mass ratio, and then subjected to first ultrasonic dispersion, first solid-liquid separation, first drying and first calcination to obtain a nickel oxide-loaded particle electrode. The composite activated carrier obtained in step 2 is mixed with the copper hydroxide precursor obtained in step 3 at a second mass ratio, and then subjected to second ultrasonic dispersion, second solid-liquid separation, second drying and second calcination to obtain a copper oxide-loaded particle electrode.

2. The preparation method according to claim 1, characterized in that, In step 2, the acid activation treatment is as follows: the carrier raw material is placed in a hydrochloric acid solution with a concentration of 0.5-2 mol / L and stirred and soaked at a speed of 300-800 r / min for 20-28 hours at room temperature; the alkali activation treatment is as follows: the acid-activated carrier is placed in a sodium hydroxide solution with a concentration of 0.5-2 mol / L and stirred and soaked at a speed of 300-800 r / min for 20-28 hours at room temperature.

3. The preparation method according to claim 1, characterized in that, In step 3, the preparation method of the nickel hydroxide precursor includes: dissolving nickel chloride hexahydrate in water, adding alkaline solution dropwise to pH 9-11 under stirring conditions to generate a precipitate, and then aging, separating solid and liquid, washing, and drying to obtain the nickel hydroxide precursor; The preparation method of the copper hydroxide precursor includes: dissolving copper nitrate hexahydrate in water, adding an alkaline solution dropwise to pH 9-11 under stirring conditions to form a precipitate, and then aging, separating the solid and liquid, washing, and drying to obtain the copper hydroxide precursor.

4. The preparation method according to claim 1, characterized in that, In step 4, the first mass ratio is 1:1-5:1, and the second mass ratio is 1:1-5:1; The conditions for the first and second calcinations independently include: heating to 600-800°C at a heating rate of 2-10°C / min under oxygen-filled conditions, and calcining for 1-4 hours.

5. The preparation method according to claim 1, characterized in that, In step 4, the time for the first ultrasonic dispersion and the second ultrasonic dispersion are independently 20-60 minutes; the rotation speed for the first solid-liquid separation and the second solid-liquid separation is independently 6000-10000 r / min; the temperature for the first drying and the second drying is independently 60-100℃, and the time is independently 4-12 hours.

6. A coal gasification slag-based composite particle electrode prepared by the preparation method according to any one of claims 1-5.

7. A three-dimensional electrode reactor for treating landfill leachate, characterized in that, include: The reactor shell contains a reaction chamber inside. An anode plate and a cathode plate are disposed in the reaction chamber, and the anode plate and the cathode plate are arranged opposite to each other. A particle electrode layer is filled between the anode plate and the cathode plate, the particle electrode layer comprising the coal gasification slag-based composite particle electrode as described in claim 8; An aeration system, located at the bottom of the reaction chamber, is used to provide microbubbles; The power supply is electrically connected to the anode plate and the cathode plate, respectively.

8. The three-dimensional electrode reactor according to claim 7, characterized in that, The three-dimensional electrode reactor also includes a circulation system, which includes a circulation pump and circulation pipelines for circulating the landfill leachate within the reaction chamber. The three-dimensional electrode reactor also includes a solar concentrator, which is located outside or above the reaction chamber to concentrate sunlight over a larger area into the light-transmitting window area. It also includes a solar power system, which comprises photovoltaic panels and a solar tracking device.

9. The three-dimensional electrode reactor according to claim 8, characterized in that, The focusing device is one or more of the following: a reflective focusing cover, a light guide tube, and a light diffuser.

10. The application of the three-dimensional electrode reactor according to any one of claims 7-9 in the removal of ammonia nitrogen and humic acid from landfill leachate.

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