Method for cyanuric acid wastewater resource utilization treatment

Abstract

The application discloses a cyanuric acid wastewater resource utilization treatment method and relates to the technical field of organic wastewater treatment. The technical scheme points of the cyanuric acid wastewater resource utilization treatment method include the following steps: adjusting the pH value and salt concentration of cyanuric acid-containing wastewater, carrying out a precipitation reaction at normal temperature, and then carrying out solid-liquid separation to obtain a clear liquid and cyanuric acid sodium salt filter residue; the cyanuric acid sodium salt filter residue is reused; the clear liquid is subjected to suction filtration treatment by using special porous carbon adsorption material to obtain suction filtration water; and the special porous carbon adsorption material after the suction filtration treatment is subjected to treatment by using a regeneration liquid flow to obtain a regeneration waste liquid and is reused. The cyanuric acid sodium salt is efficiently recovered, a high-salt substrate is simultaneously constructed to directly meet the requirements of ion membrane raw materials; the special porous carbon adsorption material has high adsorption capacity and regeneration efficiency, and the regeneration waste liquid is recycled; the total nitrogen removal rate and the TOC removal rate are high after the electrocatalytic process deep treatment, and the energy consumption is significantly reduced compared with traditional processes; and the resource utilization treatment method does not cause secondary pollution and has a significantly reduced treatment cost compared with traditional processes.

Description

Technical Field

[0001] This invention relates to the field of organic wastewater treatment technology, and more specifically, to a method for the resource utilization and treatment of cyanuric acid wastewater. Background Technology

[0002] Chloroisocyanuric acid compounds (such as trichloroisocyanuric acid and dichloroisocyanuric acid) are widely used as highly efficient and broad-spectrum disinfectants and bleaching agents in public health, water treatment, and industrial circulating cooling water systems. However, the cyanuric acid-containing wastewater generated during their production process is characterized by complex composition, high salinity, high chemical oxygen demand (COD), and high total nitrogen, becoming a technical bottleneck restricting the sustainable development of the industry. Traditional treatment methods (such as CN104803531B) use direct oxidation with sodium hypochlorite, which requires excessive addition of oxidant, resulting in high treatment costs and long reaction cycles. Furthermore, it introduces excessive sulfate ions, far exceeding the standards for ion-exchange membrane electrolysis of brine, significantly increasing the load on subsequent impurity removal.

[0003] The production of chloroisocyanuric acid and the chlor-alkali industry have a natural coupling need; the former produces cyanuric acid-containing wastewater as a byproduct, while the latter requires high-purity sodium chloride brine to produce caustic soda. However, traditional end-of-pipe treatment models have two major contradictions: first, the cyanuric acid recovery rate is low; second, salt purification is difficult, and membrane concentration processes produce concentrated water containing 1.5%-2.5% cyanuric acid, which still requires additional treatment, failing to form a closed-loop resource recovery chain.

[0004] As a key technology for deep purification, adsorption has many shortcomings in existing materials. Conventional styrene-based resins have low adsorption capacity for cyanuric acid; they are also prone to organic pollution during long-term operation, resulting in severe degradation of adsorption capacity.

[0005] With the advancement of dual carbon targets, traditional high-energy-consuming and low-efficiency wastewater treatment models can no longer meet the needs of industrial upgrading, and there is an urgent need to develop resource utilization and treatment methods for cyanuric acid wastewater. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for the resource utilization and treatment of cyanuric acid wastewater.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for the resource utilization and treatment of cyanuric acid wastewater, comprising the following steps:

[0009] (S01) Preprocessing

[0010] The pH and salt concentration of the cyanuric acid-containing wastewater are adjusted, and a precipitation reaction is carried out at room temperature until solid-liquid separation is obtained to obtain a clear liquid and sodium cyanurate filter residue. The sodium cyanurate filter residue is then reused.

[0011] (S02) Adsorption of adsorption materials

[0012] The clarified liquid is treated by suction filtration with a special porous carbon adsorbent material to obtain suction filtration permeate. The special porous carbon adsorbent material after suction filtration is treated by a regeneration liquid to obtain regenerated waste liquid, which is then reused.

[0013] The special porous carbon adsorbent material is prepared by calcining cerium nitrate modified carbon nanofibers, then calcining them with polystyrene microspheres, followed by solvent extraction and drying.

[0014] (S03) Electrocatalytic treatment

[0015] The pH of the filtration water produced by the adsorption material is adjusted to acidic, and then the TOC and nitrogen are removed through electrocatalytic oxidation for deep treatment.

[0016] In the above-described scheme of this invention, sodium chloride is added in the pretreatment step. This increases the sodium chloride concentration in the cyanuric acid wastewater, meeting the requirements for brine used in ion-exchange membrane caustic soda treatment. Furthermore, the salting-out effect reduces the solubility of sodium cyanurate, decreasing the load on subsequent processes. The process design first employs pretreatment and adsorption materials to allow most of the raw materials to be reused in production, improving resource utilization. Finally, electrocatalytic treatment removes organic matter and ammonia nitrogen through oxidation and reduction, ensuring the brine meets the requirements for ion-exchange membrane electrolysis. The treatment process is clean: no waste is generated throughout the entire process, and all resources are utilized.

[0017] Preferably, in step (S01), the pH of the original wastewater containing cyanuric acid is adjusted to 7-9, preferably 8.5, using liquid alkali, and the salt concentration is adjusted to 310±5g / L using solid sodium chloride, with a precipitation reaction time of 1-2h.

[0018] The above-mentioned solution of the present invention achieves a sodium cyanurate precipitation rate of 98% under the preferred pH condition of 8.5, while avoiding equipment corrosion and by-product generation caused by excessively high pH.

[0019] Preferably, in step (S02), the filtration rate of the special porous carbon adsorbent material is 2-5 BV / h, the flow rate of the special porous carbon adsorbent material after the regenerated liquid flows through the filtration is 1-2 BV / h, and during the flow, the temperature of the regenerated liquid is 40-70℃, and the volume of the regenerated liquid is 1-3 BV; preferably, in step (S02), the filtration rate of the special porous carbon adsorbent material is 3-4 BV / h, the flow rate of the special porous carbon adsorbent material after the regenerated liquid flows through the filtration is 1-2 BV / h, and during the flow, the temperature of the regenerated liquid is 50-60℃, and the volume of the regenerated liquid is 2 BV.

[0020] The regenerated solution is a 1-8 wt% sodium hydroxide solution; preferably, the regenerated solution is a 3-6 wt% sodium hydroxide solution.

[0021] In step (S03), the pH value of the filtration water produced by the adsorption material is adjusted to 3-5; preferably, in step (S03), the pH value of the filtration water produced by the adsorption material is adjusted to 4.

[0022] Preferably, the preparation method of the special porous carbon adsorbent material in (S02) is as follows:

[0023] (S02-1) Modified carbon nanofibers were obtained by ultrasonic treatment of a cerium nitrate solution impregnating carbon nanofibers.

[0024] (S02-2) After washing the modified carbon nanofibers to pH neutral, they were calcined in a tube furnace under nitrogen protection to obtain the calcined product;

[0025] (S02-3) The calcined product, dispersant and polystyrene microspheres are ball-milled to obtain a mixture. The mixture is placed in a tube furnace under high-purity nitrogen protection and heated, held and cooled to room temperature to obtain a heat-treated product.

[0026] (S02-4) The heat-treated product is extracted with solvent to obtain a solid product, which is then dried to obtain the special porous carbon adsorbent material.

[0027] The above-mentioned scheme of the present invention prepares a hierarchical pore structure adsorbent material with micropores, mesopores and macropores by compositing cerium nitrate modified carbon nanofibers with polystyrene microspheres, which significantly enhances the specific surface area and improves the adsorption selectivity for cyanuric acid.

[0028] Preferably, the concentration of the cerium nitrate solution in (S02-1) is 0.05-0.15M, the solid-liquid mass ratio of carbon nanofibers to the cerium nitrate solution is 1:(10-20), the ultrasonic treatment time of the cerium nitrate solution is 1-2 hours, the ultrasonic power is 200-300W, the frequency is 40-50kHz, and the ultrasonic temperature is 20-30℃; preferably, the concentration of the cerium nitrate solution in (S02-1) is 0.08-0.12M, and the solid-liquid mass ratio of the carbon nanofibers to the cerium nitrate solution is... The mass ratio is 1:(13-18), the ultrasonic treatment time of the cerium nitrate solution is 1.5h, the ultrasonic power is 220-280W, the frequency is 42-48kHz, and the ultrasonic temperature is 22-28℃; preferably, the concentration of the cerium nitrate solution in (S02-1) is 0.1M, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution is 1:15, the ultrasonic treatment time of the cerium nitrate solution is 1.5h, the ultrasonic power is 250W, the frequency is 45kHz, and the ultrasonic temperature is 25℃.

[0029] In the above-described scheme of the present invention, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution is 1:(10-20) to ensure that cerium nitrate is uniformly loaded on the fiber surface, forming highly active Ce. 4+Oxidation sites promote the chemical adsorption of cyanuric acid, and ultrasonic treatment ensures uniform dispersion of cerium nitrate nanoparticles, increasing porosity while avoiding precursor decomposition caused by high temperature.

[0030] Preferably, the solid-liquid mass ratio of the carbon nanofibers to the cerium nitrate solution is 1:(14-16); preferably, the solid-liquid mass ratio of the carbon nanofibers to the cerium nitrate solution is 1:15.

[0031] Preferably, the modified carbon nanofibers in (S02-2) are washed with deionized water until the pH is neutral, and calcined in a tube furnace at 550-600℃ for 1-3 hours with a heating rate of 4-6℃ / min; preferably, the tube furnace in (S02-2) is calcined at 580℃ for 2 hours with a heating rate of 5℃ / min.

[0032] Preferably, in step (S02-3), the calcined product and polystyrene microspheres are mixed at a mass ratio of 1:(3-5), and the amount of dispersant added is 1-3% of the total mass of the calcined product and polystyrene microspheres, wherein the dispersant is anhydrous ethanol; preferably, in step (S02-3), the calcined product and polystyrene microspheres are mixed at a mass ratio of 1:4, and the amount of dispersant added is 2% of the total mass of the calcined product and polystyrene microspheres, wherein the dispersant is anhydrous ethanol.

[0033] The above-mentioned scheme of the present invention, in which the calcined product is mixed with polystyrene microspheres at a mass ratio of 1:(3-5), can optimize the balance between the mechanical strength and adsorption performance of the adsorption material, improve the compressive strength, reduce the adsorption capacity decay rate, and anhydrous ethanol as a green dispersant, thereby improving the uniformity of the mixture, effectively reducing agglomeration, and improving the pore connectivity.

[0034] Preferably, in step (S02-3), the ball milling mixing time is 30-60 min, the ball milling speed is 80-100 rpm, and high-purity nitrogen is introduced into the tubular furnace in step (S02-3) at a flow rate of 100-200 mL / min, the temperature is raised to 800-900℃ at a rate of 9-11℃ / min and held for 2-3 hours, and then naturally cooled to room temperature under the protection of high-purity nitrogen; preferably, in step (S02-3), the ball milling mixing time is 40-50 min, the ball milling speed is 85-95 rpm, and the tubular furnace in step (S02-3)... The tube furnace is purged with high-purity nitrogen at a flow rate of 120-180 mL / min, and heated to 820-880℃ at a rate of 10℃ / min and held for 2-3 hours. It is then allowed to cool naturally to room temperature under the protection of high-purity nitrogen. Preferably, in step (S02-3), the ball milling time is 45 minutes, the ball milling speed is 90 rpm, and the tube furnace is purged with high-purity nitrogen at a flow rate of 150 mL / min, and heated to 850℃ at a rate of 10℃ / min and held for 2-3 hours. It is then allowed to cool naturally to room temperature under the protection of high-purity nitrogen.

[0035] The above-mentioned solution of the present invention enables nanoscale composite of microspheres and fibers at a ball milling speed of 80-100 rpm, thereby optimizing the hydrodynamic properties.

[0036] Preferably, in step (S02-4), the heat-treated product is subjected to solvent extraction in a Soxhlet extractor, the extraction solvent being tetrahydrofuran, the extraction time being 10-14 h, and the solid product is dried in a vacuum oven at 80-100 °C for 10-16 h; preferably, in step (S02-4), the heat-treated product is subjected to solvent extraction in a Soxhlet extractor, the extraction solvent being tetrahydrofuran, the extraction time being 11-13 h, and the solid product is dried in a vacuum oven at 85-95 °C for 11-15 h; preferably, in step (S02-4), the heat-treated product is subjected to solvent extraction in a Soxhlet extractor, the extraction solvent being tetrahydrofuran, the extraction time being 12 h, and the solid product is dried in a vacuum oven at 90 °C for 12-14 h.

[0037] The above-described solution of the present invention selectively dissolves uncarbonized polystyrene with tetrahydrofuran, retains the multi-level pore structure, and improves regeneration efficiency.

[0038] Preferably, the special porous carbon adsorbent material has hierarchical channels of micropores, mesopores and macropores, with mesopore diameters of 3-5 nm.

[0039] The above-described scheme of the present invention enables rapid diffusion and deep adsorption of cyanuric acid molecules through hierarchical channels, resulting in a large kinetic adsorption rate constant.

[0040] Preferably, the preparation method of the electrocatalytic electrode in (S03) is as follows:

[0041] (S03-1) Carbon nanotubes are acidified with mixed acid, washed with deionized water until neutral, and then dried to obtain pretreated carbon nanotubes.

[0042] (S03-2) Tetraethyl titanate is dissolved in ethanol, and then deionized water is added dropwise and stirred to obtain titanium dioxide sol;

[0043] (S03-3) Pretreated carbon nanotubes are mixed with titanium dioxide sol and ultrasonically treated. Then polyethylene glycol is added and the mixture is stirred at room temperature and aged. The gel is coated on the surface of conductive glass, dried, and then calcined in a muffle furnace to obtain the electrocatalytic electrode.

[0044] The above-mentioned scheme of the present invention efficiently introduces carboxyl and sulfonic acid groups onto the surface of carbon nanotubes through the synergistic oxidation of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide, significantly improving their chemical bonding ability with titanium dioxide and significantly enhancing the interfacial bonding energy. Subsequently, the hydrolysis conditions of tetraethyl titanate are optimized to prepare anatase titanium dioxide sol with uniform particle size, reducing the phase transition temperature during subsequent calcination and saving energy. Finally, through the optimization of the mass ratio of carbon nanotubes to titanium dioxide and the interaction with polyethylene glycol, a three-dimensional porous structure with a large specific surface area is formed, improving the mass transfer efficiency. At the same time, the conductive network of carbon nanotubes increases the electrode conductivity and the exposure ratio of catalytic active sites.

[0045] Preferably, the mixed acid in (S03-1) is a mixture of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide in a volume ratio of 1:(1-3):1, and the carbon nanotubes in (S03-1) are washed with deionized water after being refluxed with the mixed acid at 80°C for 4-6 hours.

[0046] In the above-described scheme of this invention, concentrated sulfuric acid serves as the primary oxidant, introducing carboxyl groups onto the surface of carbon nanotubes and enhancing their surface polarity. The addition of concentrated sulfuric acid catalyzes the oxidation of nitric acid and introduces sulfonic acid groups through sulfonation, thereby enhancing the hydrophilicity of the carbon nanotubes. Hydrogen peroxide decomposes to generate hydroxyl radicals, selectively oxidizing defect sites on the carbon nanotubes and synergistically enriching carboxyl groups with nitric acid, thus strengthening the chemical bond between the carbon nanotubes and titanium dioxide. Hydrogen peroxide partially replaces the strong acid, significantly reducing the amount of nitric acid used and significantly lowering the concentration of nitrate ions in the waste acid, thus reducing subsequent treatment costs. Simultaneously, it avoids the high corrosive risk of the pure concentrated sulfuric acid system, extending the service life of the reactor. Furthermore, the gentle oxidation by hydrogen peroxide prevents excessive breakage of carbon nanotubes, thus avoiding a decrease in conductivity.

[0047] Preferably, the pretreated carbon nanotubes and titanium dioxide sol in (S03-2) are mixed at a mass ratio of 1:(3-5), and the mixture in (S03-2) is stirred at a speed of 200-300 rpm for 1-2 hours; preferably, the pretreated carbon nanotubes and titanium dioxide sol in (S03-2) are mixed at a mass ratio of 1:4, and the mixture in (S03-2) is stirred at a speed of 220-280 rpm for 1-2 hours.

[0048] In the above-mentioned scheme of the present invention, the pretreated carbon nanotubes and titanium dioxide sol are mixed at a mass ratio of 1:(3-5) to ensure that TiO2 fully coats the carbon nanotubes and retains a certain porosity to promote mass transfer; at the same time, the electrode conductivity and the photocatalytic activity of titanium dioxide reach the optimal balance, thereby promoting the catalytic oxidation efficiency.

[0049] Preferably, the amount of polyethylene glycol added is 0.1-0.2 times the mass of carbon nanotubes, and in step (S03-3), the ultrasonic treatment is performed for 30-60 min, the stirring treatment for 1-2 h, the aging treatment for 22-26 h, and the calcination in a muffle furnace at 400-500℃ for 1-3 h; preferably, the amount of polyethylene glycol added is 0.1-0.2 times the mass of carbon nanotubes, and in step (S03-3), the ultrasonic treatment is performed for 40-50 min, the stirring treatment for 1-2 h, the aging treatment for 23-25 ​​h, and the calcination in a muffle furnace at 420-480℃ for 2 h.

[0050] In the above-mentioned scheme of the present invention, polyethylene glycol decomposes during calcination to form a composite structure of mesoporous and macroporous structures, thereby increasing the specific surface area; at the same time, polyethylene glycol chains entangle carbon nanotubes to prevent agglomeration during ultrasonic treatment and improve the uniformity of carbon nanotube dispersion; after the pyrolysis of polyethylene glycol, a microporous framework is left behind, which can improve the electrode hardness and maintain high catalytic activity.

[0051] Preferably, the current density of the electrocatalytic treatment in step (S03) is 50-100 mA / cm². 2 55mA / cm is preferred 2 The oxidation time is 0.5-1h.

[0052] The above-described solution of the present invention has a current density of 50-100 mA / cm². 2 Within this range, the TOC degradation rate is faster, the electrode life is extended, and the overall treatment cost is effectively controlled.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] This invention achieves full resource utilization of cyanuric acid-containing wastewater through a synergistic process of pretreatment, staged adsorption, and electrocatalytic upgrading, resulting in significant treatment efficiency and environmental benefits. First, the pretreatment step increases the precipitation rate of sodium cyanurate at pH 8.5, simultaneously constructing a 310 g / L high-salt matrix. This recovers over 95% of the cyanuric acid while meeting the brine concentration requirements of the ion-exchange membrane, reducing the load on subsequent treatments. Subsequently, a staged porous adsorption material prepared by calcining cerium nitrate-modified carbon nanofibers with polystyrene significantly improves adsorption capacity and regeneration efficiency, while effectively reusing the regenerated wastewater, reducing alkali consumption. Finally, through the synergistic oxidation-reduction effect of a carbon nanotube / titanium dioxide composite electrode, both TOC and total nitrogen removal rates exceed 98%, making it suitable as a raw material for ion-exchange membrane caustic soda treatment. This method achieves full resource utilization of wastewater, significantly reducing treatment costs compared to traditional processes. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the process flow for the resource utilization and treatment method of cyanuric acid-containing wastewater proposed in this invention.

[0056] Figure 2 This is a schematic diagram of the raw water photograph used in Embodiment 1 of the present invention;

[0057] Figure 3 This is a schematic diagram of water quality photographs taken in Example 1 of this invention, showing the pH value adjusted to 3.

[0058] Figure 4 This is a schematic diagram of water quality photographs taken during 0.5 hours of electrocatalytic oxidation according to Example 1 of this invention;

[0059] Figure 5 This is a schematic diagram of the water quality photographs taken during 1 hour of electrocatalytic oxidation, as presented in Example 1 of this invention. Detailed Implementation

[0060] A method for the resource utilization and treatment of cyanuric acid wastewater, comprising the following steps:

[0061] (S01) Preprocessing

[0062] The pH and salt concentration of the cyanuric acid-containing wastewater are adjusted, and the precipitation reaction is carried out at room temperature until solid-liquid separation to obtain clear liquid and sodium cyanurate filter residue. The sodium cyanurate filter residue is reused. In (S01), the pH of the original cyanuric acid-containing wastewater is adjusted to 7-9 using liquid alkali, and the salt concentration is adjusted to 310±5g / L using solid sodium chloride. The precipitation reaction time is 1-2h.

[0063] (S02) Adsorption of adsorption materials

[0064] The clarified liquid is treated by suction filtration with a special porous carbon adsorbent material to obtain suction filtration permeate. The special porous carbon adsorbent material after suction filtration is treated by regeneration liquid to obtain regenerated waste liquid, which is then reused.

[0065] Among them, the special porous carbon adsorbent material is prepared by calcining cerium nitrate modified carbon nanofibers, then calcining them with polystyrene microspheres, followed by solvent extraction and drying.

[0066] (S02) The filtration rate of the special porous carbon adsorbent material is 2-5 BV / h. The flow rate of the regenerated liquid after passing through the filtration material is 1-2 BV / h. During the flow, the temperature of the regenerated liquid is 40-70℃ and the volume of the regenerated liquid is 1-3 BV. The regenerated liquid is a 1-8 wt% sodium hydroxide solution.

[0067] The preparation method of the special porous carbon adsorbent material in (S02) is as follows:

[0068] Modified carbon nanofibers were obtained by ultrasonic treatment of a cerium nitrate solution impregnating carbon nanofibers (S02-1); the concentration of the cerium nitrate solution in (S02-1) was 0.05-0.15M, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution was 1:(10-20), the ultrasonic treatment time of the cerium nitrate solution was 1-2h, the ultrasonic power was 200-300W, the frequency was 40-50kHz, and the ultrasonic temperature was 20-30℃; the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution was 1:(14-16).

[0069] (S02-2) After washing the modified carbon nanofibers to pH neutral, they were calcined in a tube furnace under nitrogen protection to obtain the calcined product; (S02-2) The modified carbon nanofibers were washed with deionized water to pH neutral, and calcined in a tube furnace at 550-600℃ for 1-3 hours, with a heating rate of 4-6℃ / min.

[0070] (S02-3) The calcined product, dispersant and polystyrene microspheres are ball-milled and mixed to obtain a mixture. The mixture is placed in a tube furnace under high-purity nitrogen protection and heated, held and cooled to room temperature to obtain a heat-treated product. In (S02-3), the calcined product and polystyrene microspheres are mixed at a mass ratio of 1:(3-5). The amount of dispersant added is 1-3% of the total mass of the calcined product and polystyrene microspheres. The dispersant is anhydrous ethanol.

[0071] In (S02-3), the ball milling mixing time is 30-60 min, the ball milling speed is 80-100 rpm, and high-purity nitrogen is introduced into the tube furnace in (S02-3) with a flow rate controlled at 100-200 mL / min. The temperature is raised to 800-900℃ at a rate of 9-11℃ / min and held for 2-3 h. The furnace is then naturally cooled to room temperature under the protection of high-purity nitrogen.

[0072] (S02-4) The heat-treated product is solvent-extracted to obtain a solid product, which is then dried to obtain a special porous carbon adsorbent material; (S02-4) The heat-treated product is placed in a Soxhlet extractor for solvent extraction, the extraction solvent is tetrahydrofuran, the extraction time is 10-14h, and the solid product is dried in a vacuum oven at 80-100℃ for 10-16h; the special porous carbon adsorbent material has hierarchical channels of micropores, mesopores and macropores, and the mesopore pore size is 3-5nm;

[0073] (S03) Electrocatalytic treatment

[0074] The pH of the filtration water from the adsorption material is adjusted to acidic, and then subjected to deep electrocatalytic oxidation to remove TOC and nitrogen; the current density of the electrocatalytic treatment in (SO3) is 50-100 mA / cm³. 2 The oxidation time is 0.5-1h; the pH value of the filtration water produced by the adsorption material in (SO3) is adjusted to 3-5;

[0075] The preparation method of the electrocatalytic electrode in (S03) is as follows:

[0076] (S03-1) Carbon nanotubes are acidified using mixed acid, washed with deionized water until neutral, and then dried to obtain pretreated carbon nanotubes; (S03-1) The mixed acid is a mixture of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide in a volume ratio of 1:(1-3):1. The carbon nanotubes in (S03-1) are refluxed with mixed acid at 75-85℃ for 4-6 hours and then washed with deionized water.

[0077] (S03-2) Tetraethyl titanate is dissolved in ethanol, and then deionized water is added dropwise and stirred to obtain titanium dioxide sol; the pretreated carbon nanotubes in (S03-2) are mixed with titanium dioxide sol at a mass ratio of 1:(3-5), and the mixture in (S03-2) is stirred at a speed of 200-300 rpm for 1-2 hours.

[0078] (S03-3) Pretreated carbon nanotubes were mixed with titanium dioxide sol and ultrasonically treated. Then polyethylene glycol was added and stirred at room temperature for aging. The gel was coated on the surface of conductive glass, dried, and calcined in a muffle furnace to obtain an electrocatalytic electrode. The amount of polyethylene glycol added was 0.1-0.2 times the mass of carbon nanotubes. (S03-3) was ultrasonically treated for 30-60 min, stirred for 1-2 h, aged for 22-26 h, and calcined in a muffle furnace at 400-500℃ for 1-3 h.

[0079] Reference Figures 1 to 5 As shown.

[0080] Example 1

[0081] A method for the resource utilization and treatment of cyanuric acid wastewater, comprising the following steps:

[0082] The original cyanuric acid wastewater was collected, and the pH was first adjusted to 8.5 by adding liquid alkali. Then, sodium chloride was added to achieve a brine concentration of 310 g / L. After stirring and allowing the solution to precipitate at room temperature for 2 hours, the mixture was filtered. The clarified filtrate was then treated by adsorption filtration using a single-stage adsorption tower at a filtration rate of 2 BV / h. Special porous carbon adsorption material was selected, and the adsorption endpoint was reached after 40 BV of adsorption. A 4% sodium hydroxide solution was used at 50℃, with a regeneration flow rate of 1 BV / h, consuming a total of 2 BV of regenerated liquid. Hydrochloric acid was added to the permeate from the adsorption filtration to adjust the pH to 3, followed by electrocatalytic treatment at a current density of 55 mA / cm³. 2 The reaction was stopped after 1 hour of oxidation.

[0083] The preparation method of the special porous carbon adsorbent material is as follows:

[0084] (S02-1) Carbon nanofibers were impregnated in a 0.1M cerium nitrate solution with a solid-liquid mass ratio of 1:15, and ultrasonically treated for 1.5 h at a power of 250 W, a frequency of 45 kHz, and a temperature of 25 °C.

[0085] (S02-2) The carbon nanofibers were then rinsed with deionized water until the pH was neutral. Under nitrogen protection, the washed carbon nanofibers were placed in a tube furnace and calcined at 570°C for 2 hours with a heating rate of 5°C / min.

[0086] (S02-3) The calcined product was mixed with polystyrene microspheres at a mass ratio of 1:4. 2% (by mass) of anhydrous ethanol was added to the mixture. The mixture was then milled in a ball mill for 45 min at a speed of 90 rpm. The resulting mixture was placed in a tube furnace, and high-purity nitrogen gas was introduced at a flow rate of 150 mL / min. The temperature was increased to 850 °C at a rate of 10 °C / min and held for 2.5 h. The mixture was then allowed to cool naturally to room temperature under the protection of high-purity nitrogen.

[0087] (S02-4) The cooled mixture was placed in a Soxhlet extractor for solvent extraction with tetrahydrofuran as the solvent for 12 hours. The mixture was then placed in a vacuum oven and dried at 90°C for 14 hours to obtain a special porous carbon adsorbent material.

[0088] The preparation method of the electrocatalytic electrode in (S03) is as follows:

[0089] (S03-1) Carbon nanotubes were acidified using a mixed acid, wherein the mixed acid consisted of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide mixed in a volume ratio of 1:2:1. After refluxing at 80°C for 5 hours, the carbon nanotubes were washed with deionized water until neutral and then dried to obtain pretreated carbon nanotubes.

[0090] (S03-2) Dissolve tetraethyl titanate in ethanol, then add deionized water dropwise and stir at 250 rpm for 1.5 h to obtain titanium dioxide sol;

[0091] (S03-3) Pretreated carbon nanotubes and titanium dioxide sol were mixed at a mass ratio of 1:4 and ultrasonically treated for 45 min. Then, polyethylene glycol with a mass of 0.15 times that of carbon nanotubes was added and stirred at room temperature for 1.5 h. After aging for 24 h, the gel was coated on the surface of conductive glass, dried, and placed in a muffle furnace and calcined at 450 °C for 2 h to obtain an electrocatalytic electrode.

[0092] TOC and TN were determined in the permeate from different treatment stages in Example 1. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0093] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 6.5 3.2

[0094] Example 2

[0095] In the preparation of the special porous carbon adsorbent material, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution is 1:10, and the remaining steps are the same as in Example 1.

[0096] TOC and TN were determined in the permeate from different treatment stages in Example 2. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0097] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 13.9 20.1 4 Electrocatalytic water production 7.2 5.9

[0098] Example 3

[0099] In the preparation of the special porous carbon adsorbent material, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution is 1:20, and the remaining steps are the same as in Example 1.

[0100] TOC and TN were determined in the permeate from different treatment stages in Example 3. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0101] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for water filtration 14.7 22.0 4 Electrocatalytic water production 8.4 7.5

[0102] Example 4

[0103] In the preparation of the special porous carbon adsorbent material, the calcined product is mixed with polystyrene microspheres at a mass ratio of 1:3, and the remaining steps are the same as in Example 1.

[0104] TOC and TN were determined in the permeate from different treatment stages in Example 4. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0105] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 13.1 19.2 4 Electrocatalytic water production 6.8 3.8

[0106] Example 5

[0107] In the preparation of the special porous carbon adsorbent material, the calcined product is mixed with polystyrene microspheres at a mass ratio of 1:5, and the remaining steps are the same as in Example 1.

[0108] TOC and TN were determined in the permeate from different treatment stages in Example 5. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0109] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 13.7 18.6 4 Electrocatalytic water production 7.1 4.0

[0110] Example 6

[0111] In the preparation of the electrocatalytic electrode, S11-3 pretreated carbon nanotubes and titanium dioxide sol were mixed at a mass ratio of 1:3, and the remaining steps were the same as in Example 1.

[0112] TOC and TN were determined in the permeate from different treatment stages in Example 6. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0113] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 6.9 3.6

[0114] Example 7

[0115] In the preparation of the electrocatalytic electrode, the carbon nanotubes pretreated with S11-3 were mixed with titanium dioxide sol at a mass ratio of 1:5, and the remaining steps were the same as in Example 1.

[0116] TOC and TN were determined in the permeate from different treatment stages in Example 7. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0117] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 6.6 3.5

[0118] Example 8

[0119] In the preparation of the electrocatalytic electrode, the amount of S11-3 polyethylene glycol added was 0.1 times the mass of the carbon nanotubes, and the remaining steps were the same as in Example 1.

[0120] TOC and TN were determined in the permeate from different treatment stages in Example 8. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0121] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 7.1 3.3

[0122] Example 9

[0123] In the preparation of the electrocatalytic electrode, the amount of S11-3 polyethylene glycol added was 0.2 times the mass of the carbon nanotubes, and the remaining steps were the same as in Example 1.

[0124] TOC and TN were determined in the permeate from different treatment stages in Example 9. TOC was determined according to HJ501-2009, "Determination of Total Organic Carbon in Water Quality - Combustion Oxidation-Non-Dispersive Infrared Absorption Method," using a Shimadzu TOC-L instrument. The error range was ±3%, and each sample was measured in triplicate, with the average value taken. TN was determined according to HJ636-2012, "Determination of Total Nitrogen in Water Quality - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometry," using a HACHDR6000 UV-Vis spectrophotometer. The error range was ±5%, and each sample was measured in triplicate, with the average value taken. Specific experimental results are shown in the table below.

[0125] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 6.8 3.2

[0126] Comparative Example 1

[0127] No NaCl was added during the pretreatment stage. The pH was adjusted to 8.5 and then the sample was filtered directly. The remaining steps were the same as in Example 1.

[0128] The TOC and TN of the permeate from different treatment stages in Comparative Example 1 were measured, and the specific experimental results are shown in the table below.

[0129] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 216 281 3 Adsorption material for filtration of water 46.5 86.9 4 Electrocatalytic water production 19.8 26.5

[0130] Comparative Example 2

[0131] The adsorption stage used conventional styrene-based adsorbent material, purchased from Shanghai Yuanye Biotechnology Co., Ltd., and the remaining steps were the same as in Example 1.

[0132] The TOC and TN of the permeate from different treatment stages in Comparative Example 2 were measured, and the specific experimental results are shown in the table below.

[0133] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 38.4 57.3 4 Electrocatalytic water production 12.6 15.2

[0134] Comparative Example 3

[0135] The preparation process of the special porous carbon adsorbent material does not involve the addition of cerium nitrate, and the remaining steps are the same as in Example 1.

[0136] The TOC and TN of the permeate from different treatment stages in Comparative Example 3 were measured, and the specific experimental results are shown in the table below.

[0137] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 52.0 64.1 4 Electrocatalytic water production 18.3 32.6

[0138] Comparative Example 4

[0139] The preparation process of the special porous carbon adsorbent material does not involve the addition of polystyrene microspheres, and the remaining steps are the same as in Example 1.

[0140] The TOC and TN of the permeate from different treatment stages in Comparative Example 4 were measured, and the specific experimental results are shown in the table below.

[0141] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 63.2 58.9 4 Electrocatalytic water production 32.7 26.5

[0142] Comparative Example 5

[0143] The preparation process (S3-2) of the special porous carbon adsorbent material does not involve the addition of anhydrous ethanol, and the remaining steps are the same as in Example 1.

[0144] The TOC and TN of the permeate from different treatment stages in Comparative Example 5 were measured, and the specific experimental results are shown in the table below.

[0145] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 42.1 53.6 4 Electrocatalytic water production 16.9 19.8

[0146] Comparative Example 6

[0147] Untreated carbon nanofibers were used instead of the dedicated porous carbon adsorbent material, and the remaining steps were the same as in Example 1.

[0148] The TOC and TN of the permeate from different treatment stages in Comparative Example 6 were measured, and the specific experimental results are shown in the table below.

[0149] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 78.3 83.9 4 Electrocatalytic water production 42.3 49.6

[0150] Comparative Example 7

[0151] In the preparation of the electrocatalytic electrode, hydrogen peroxide was not added to the mixed acid, and the remaining steps were the same as in Example 1.

[0152] The TOC and TN of the permeate from different treatment stages in Comparative Example 7 were measured, and the specific experimental results are shown in the table below.

[0153] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 7.6 4.5

[0154] Comparative Example 8

[0155] Polyethylene glycol was not added during the preparation of the electrocatalytic electrode, and the remaining steps were the same as in Example 1.

[0156] The TOC and TN of the permeate from different treatment stages in Comparative Example 8 were measured, and the specific experimental results are shown in the table below.

[0157] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 6.9 3.5

[0158] Comparative Example 9

[0159] Titanium dioxide sol was not added during the preparation of the electrocatalytic electrode; the remaining steps were the same as in Example 1.

[0160] The TOC and TN of the permeate from different treatment stages in Comparative Example 9 were measured, and the specific experimental results are shown in the table below.

[0161] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 9.1 11.3

[0162] Comparative Example 10

[0163] The carbon nanotubes were not acidified during the preparation of the electrocatalytic electrode; the remaining steps were the same as in Example 1.

[0164] The TOC and TN of the permeate from different treatment stages in Comparative Example 10 were measured, and the specific experimental results are shown in the table below.

[0165] Serial Number name TOC (mg / L) TN (mg / L) 1 raw wastewater 564 358 2 Pretreated product water 95 113 3 Adsorption material for filtration of water 12.6 18 4 Electrocatalytic water production 8.2 7.5

[0166] The experimental data above show that the pretreatment stage, by adjusting the pH and adding sodium chloride to induce precipitation, significantly reduced the TOC and TN content of the wastewater. This step effectively removed most of the organic matter and nitrogenous pollutants, laying a good foundation for subsequent treatment. In the adsorption stage, the selective adsorption of specialized porous carbon adsorbents enabled deep purification of organic matter and nitrogenous pollutants in the wastewater, further removing TOC and TN. The electrocatalytic treatment stage, as the final treatment step, effectively decomposed recalcitrant organic matter, while electrocatalysis removed residual nitrogenous pollutants, reducing the TOC and TN content of the wastewater and ensuring that the product water quality meets the standards for brine used in ion-exchange membrane electrolysis.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for the resource utilization and treatment of cyanuric acid wastewater, characterized in that: The method includes the following steps: (S01) Preprocessing The pH and salt concentration of the cyanuric acid-containing wastewater were adjusted, and a precipitation reaction was carried out at room temperature until solid-liquid separation was obtained to obtain a clear liquid and sodium cyanurate filter residue, which was then reused; the salt concentration was adjusted to 310±5 g / L using sodium chloride solid. (S02) Adsorption of adsorption materials The clarified liquid is treated by suction filtration with a special porous carbon adsorbent material to obtain suction filtration permeate. The special porous carbon adsorbent material after suction filtration is treated by a regeneration liquid to obtain regenerated waste liquid, which is then reused. The special porous carbon adsorbent material is prepared by calcining cerium nitrate modified carbon nanofibers, then calcining them with polystyrene microspheres, followed by solvent extraction and drying. The preparation method of the special porous carbon adsorbent material in (S02) is as follows: (S02-1) Modified carbon nanofibers were obtained by ultrasonic treatment of a cerium nitrate solution impregnating carbon nanofibers. (S02-2) After washing the modified carbon nanofibers to pH neutral, they were calcined in a tube furnace under nitrogen protection to obtain the calcined product; (S02-3) The calcined product, dispersant and polystyrene microspheres are ball-milled to obtain a mixture. The mixture is placed in a tube furnace under high-purity nitrogen protection, heated to 800-900℃, held for 2-3 hours, and cooled to room temperature to obtain a heat-treated product. (S02-4) The heat-treated product is extracted with solvent to obtain a solid product, which is then dried to obtain the special porous carbon adsorbent material; The dispersant is anhydrous ethanol; (S03) Electrocatalytic treatment The pH of the filtration water produced by the adsorption material is adjusted to acidic, and then the TOC and nitrogen are removed through electrocatalytic oxidation for deep treatment.

2. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 1, characterized in that: In step (S01), the pH of the original wastewater containing cyanuric acid is adjusted to 7-9 using liquid alkali, and the precipitation reaction time is 1-2 hours. The special porous carbon adsorbent material in (S02) has a filtration rate of 2-5 BV / h, and the flow rate of the special porous carbon adsorbent material after the regenerated liquid flows through the filtration is 1-2 BV / h. During the flow, the temperature of the regenerated liquid is 40-70℃, and the volume of the regenerated liquid is 1-3 BV. The regenerated solution is a 1-8 wt% sodium hydroxide solution; In step (S03), the pH value of the filtration water produced by the adsorption material is adjusted to 3-5.

3. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 1, characterized in that: The concentration of the cerium nitrate solution in (S02-1) is 0.05-0.15M, the solid-liquid mass ratio of carbon nanofibers to cerium nitrate solution is 1:(10-20), the ultrasonic treatment time of the cerium nitrate solution is 1-2h, the ultrasonic power is 200-300W, the frequency is 40-50kHz, and the ultrasonic temperature is 20-30℃.

4. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 1, characterized in that: The modified carbon nanofibers in (S02-2) are washed with deionized water until the pH is neutral, and the tube furnace in (S02-2) is calcined at 550-600℃ for 1-3 hours with a heating rate of 4-6℃ / min. In step (S02-3), the calcined product is mixed with polystyrene microspheres at a mass ratio of 1:(3-5), and the amount of dispersant added is 1-3% of the total mass of the calcined product and polystyrene microspheres. The dispersant is anhydrous ethanol.

5. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 1, characterized in that: In step (S02-3), the ball milling mixing time is 30-60 min, the ball milling speed is 80-100 rpm, and high-purity nitrogen is introduced into the tube furnace in step (S02-3) at a flow rate of 100-200 mL / min. The temperature is raised to 800-900℃ at a rate of 9-11℃ / min and held for 2-3 h. The furnace is then naturally cooled to room temperature under the protection of high-purity nitrogen. The heat-treated product in (S02-4) is subjected to solvent extraction in a Soxhlet extractor. The extraction solvent is tetrahydrofuran, and the extraction time is 10-14 h. The solid product is then dried in a vacuum oven at 80-100 °C for 10-16 h.

6. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 1, characterized in that: The preparation method of the electrocatalytic electrode in (S03) is as follows: (S03-1) Carbon nanotubes are acidified with mixed acid, washed with deionized water until neutral, and then dried to obtain pretreated carbon nanotubes. (S03-2) Tetraethyl titanate is dissolved in ethanol, and then deionized water is added dropwise and stirred to obtain titanium dioxide sol; (S03-3) Pretreated carbon nanotubes are mixed with titanium dioxide sol and ultrasonically treated. Then polyethylene glycol is added and the mixture is stirred at room temperature and aged. The gel is coated on the surface of conductive glass, dried, and then calcined in a muffle furnace to obtain the electrocatalytic electrode.

7. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 6, characterized in that: The mixed acid in (S03-1) is a mixture of concentrated sulfuric acid, concentrated nitric acid and hydrogen peroxide in a volume ratio of 1:(1-3):

1. The carbon nanotubes in (S03-1) are washed with deionized water after being refluxed in the mixed acid at 75-85℃ for 4-6 hours.

8. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 6, characterized in that: The pretreated carbon nanotubes and titanium dioxide sol in (S03-2) are mixed at a mass ratio of 1:(3-5), and the mixture in (S03-2) is stirred at a speed of 200-300 rpm for 1-2 hours.

9. The method for resource utilization and treatment of cyanuric acid wastewater according to claim 6, characterized in that: The amount of polyethylene glycol added is 0.1-0.2 times the mass of carbon nanotubes. In (S03-3), the ultrasonic treatment is performed for 30-60 min, the stirring treatment is performed for 1-2 h, the aging treatment is performed for 22-26 h, and the muffle furnace is calcined at 400-500℃ for 1-3 h.

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