A carbon nitride composite biochar catalytic material for salt-containing wastewater treatment and a device thereof

Abstract

The present application relates to a kind of carbon nitride composite biochar catalytic materials for salt-containing wastewater treatment and its matching device.The above-mentioned material uses functional group doping strategy to modify carbon nitride, constructs salt ion shielding layer by surface hydroxylation modification, effectively inhibits the poisoning effect of Cl ‑ 、SO4 2‑ Etc salt to active site, while widening the light absorption range and enhancing the oxidation capacity.Using biochar composite carbon nitride material with adsorption and catalysis dual function, further improve its catalytic capacity.The present application uses "pre-coagulation sedimentation tank+ozone photocatalysis" integrated wastewater treatment equipment, which combines the advantages of physical, chemical and advanced oxidation technology, realizes the efficient removal of pollutants in high-salinity wastewater through multi-stage synergistic effect.

Description

Technical Field

[0001] This application relates to the field of advanced oxidation treatment of wastewater, specifically to a carbon nitride composite biochar catalytic material and its supporting device for the treatment of saline wastewater. Technical Background

[0002] With the increasing ecological risks and growing complexity of emerging pollutants (ECs) in industrial park wastewater, traditional treatment technologies face bottlenecks such as low removal efficiency and weak resistance to salt interference. While heterogeneous ozone catalytic oxidation (HCO3) is effective in degrading ECs, it is limited by low O3 solubility, short transport distance, and catalyst deactivation and toxic byproduct formation caused by salt ions (such as Cl-). Photocatalytic systems achieve pollutant degradation through photogenerated electron-hole pairs driving redox reactions, but they are difficult to operate stably due to high carrier recombination rates, intermediate product accumulation, and mass transfer resistance at the reaction interface. Therefore, constructing an ozone catalytic oxidation coupled with photocatalysis is key to overcoming the limitations of single technologies, and its core lies in designing the structure of catalytic materials and regulating their catalytic activity.

[0003] Carbon nitride exhibits excellent catalytic activity in ozone catalytic oxidation coupled with photocatalysis, but its high photogenerated carrier recombination rate, weak conductivity, and narrow photoresponse range limit its practical application. Through synergistic modification strategies such as bandgap engineering, heteroatom doping, and functional group modification (e.g., introducing alkali / alkaline earth metal hydroxides), electron injection enhancement, directional construction of surface hydroxyl active sites, and charge separation optimization can be achieved. Simultaneously, the material is endowed with resistance to salt ions (Cl... - SO4 2- The interference resistance is enhanced by maintaining the stability of catalytic active sites through electrostatic repulsion and a stable pore structure, significantly improving the treatment performance of high-salinity wastewater. Biochar (BC) can form conjugated bonds with carbon nitride under mesophilic conditions, and the spin density and electronic configuration are regulated by nitrogen-rich components, thereby strengthening interfacial charge transfer. Furthermore, to address the challenges of catalyst particle agglomeration, difficulty in separation, and lack of recyclability, a binder is used to load carbon nitride composite biochar materials onto alumina microspheres, simultaneously improving catalytic activity.

[0004] Furthermore, the integrated wastewater treatment equipment of "pre-coagulation sedimentation tank + ozone photocatalysis" provided by this invention combines the advantages of physical, chemical and advanced oxidation technologies, and can effectively remove pollutants from high-salt wastewater through multi-stage synergistic effects. Summary of the Invention

[0005] To address the challenges of existing catalysts, such as agglomeration, difficulty in separation, and lack of recyclability, this invention provides a method for preparing carbon nitride-based composite biochar catalytic materials for saline wastewater treatment. A functional group doping strategy is employed to modify carbon nitride, broadening its light absorption range and enhancing its oxidation capacity. Simultaneously, the catalytic activity is further improved by combining biochar, which possesses both adsorption and catalytic functions, with the carbon nitride material. Furthermore, this invention utilizes an integrated wastewater treatment device combining a pre-coagulation sedimentation tank and ozone photocatalysis, integrating the advantages of physical, chemical, and advanced oxidation technologies to achieve highly efficient removal of pollutants from high-salinity wastewater through multi-stage synergistic effects.

[0006] One aspect of the present invention provides a carbon nitride composite biochar catalytic material for the treatment of saline wastewater, the preparation steps of which are as follows:

[0007] Preparation of S1 tubular carbon nitride:

[0008] A certain mass of melamine was added to water and ultrasonically heated until completely dissolved to obtain solution I; a certain mass of cyanuric acid was added to water and ultrasonically heated until completely dissolved to obtain solution II; solution II was added dropwise to solution I in a boiling water bath while continuing to heat and stir, and after washing with water, precipitate I was obtained; precipitate I was subjected to a hydrothermal reaction in a hydrothermal reactor, and the product obtained after the reaction was collected and freeze-dried to obtain precipitate II; precipitate II was calcined under a nitrogen atmosphere to obtain product I.

[0009] Preparation of S2 functional group-doped carbon nitride:

[0010] A certain mass of product I and a certain concentration of dopant were subjected to a hydrothermal reaction in a hydrothermal reactor. The resulting product was collected and dried to obtain product II.

[0011] Preparation of S3 biochar:

[0012] After grinding and sieving the biomass, it was mixed evenly with alkali in an aqueous solution at a certain mass ratio and soaked. After drying, it was calcined under a nitrogen atmosphere. The product was then post-treated, collected, and dried to obtain product III.

[0013] Preparation of S4 carbon nitride composite biochar material:

[0014] Carbon nitride and biochar were mixed at a certain mass ratio and ultrasonically stirred in an aqueous solution until homogeneous. The resulting product was collected and dried to obtain precipitate III. Precipitate III was then calcined under a nitrogen atmosphere to obtain product IV.

[0015] Preparation of S5 biochar balls:

[0016] A certain mass of carbon nitride composite biochar material was weighed, a binder was added, and the mixture was stirred into a paste using a glass rod. Spherical molds and alumina pellets were prepared for granulation. After freezing and shaping the molds, the product was demolded and dried at a certain temperature to obtain product V.

[0017] Furthermore, in step S3, the specific steps for grinding and sieving the biomass are as follows: after washing and drying the biomass, grind it into powder, and then pass the obtained powder through a 200-mesh sieve for later use.

[0018] Furthermore, in step S3, the post-treatment steps are as follows: the product is added to 1 mol / L hydrochloric acid for acid leaching for 1-3 hours, then subjected to acid heat treatment at 80-100℃ for 1-3 hours, naturally cooled, washed with ethanol 3-5 times, and finally washed with deionized water until the solution is neutral.

[0019] Optionally, in step S1, the molar ratio of melamine to cyanuric acid is 1:0.5-1.5.

[0020] Optionally, in step S2, the mass of the tubular carbon nitride is 0.5-2.5g; the concentration of the dopant is 0.1-0.5mg / L; and the dopant includes one or more of NaOH, KOH, LiOH, Ca(OH)2, and Mg(OH)2.

[0021] Optionally, in step S3, the biomass includes one or more of the following: seaweed, algae, straw, fruit shells, and sawdust; the alkali includes one or more of the following: potassium hydroxide, sodium carbonate, sodium bicarbonate, and ammonia water; the mass ratio of biomass to alkali is 1:1-4, and the soaking time is 4-12 hours.

[0022] Optionally, in step S4, the mass ratio of carbon nitride to biochar is 1:1-5.

[0023] Optionally, in step S5, the mass of the carbon nitride composite biochar material is 0.5-2.5g; the binder includes one or more of epoxy resin, waterborne polyurethane, acrylate, and phenolic resin; the mold is placed in a refrigerator for freezing and shaping for 1-3 hours before demolding; the demolded product is dried at 160-200℃ for 1-5 hours.

[0024] Optionally, in step S1, the hydrothermal reaction temperature is 140-200℃ and the hydrothermal reaction time is 4-12h; in step S2, the hydrothermal reaction temperature is 120-180℃ and the hydrothermal reaction time is 14-20h.

[0025] Optionally, in steps S1, S3, and S4, the nitrogen flow rate is 2-5 mL / min, and the heating rate is 2-15 °C / min. Optionally, in step S1, the calcination reaction temperature is 400-800 °C, and the calcination reaction time is 2-6 h; in step S3, the calcination reaction temperature is 500-800 °C, and the calcination reaction time is 1-6 h; in step S4, the calcination reaction temperature is 300-600 °C, and the calcination reaction time is 1-5 h.

[0026] Optionally, in steps S1 and S4, the ultrasound time is 0.2-0.5 hours and the ultrasound frequency is 20-60 kHz.

[0027] Optionally, in step S1, the heating temperature is 60-90℃; in steps S2, S3, and S4, the drying temperature is 40-80℃.

[0028] Another aspect of the present invention provides an integrated wastewater treatment device for the treatment of saline wastewater, comprising a box (1), a coagulation sedimentation chamber (2), a photo-ozone synergistic catalytic reaction chamber (3), and a central control room (4).

[0029] The coagulation sedimentation chamber (2) includes a dosing pump (21), a first water pump (22), a first water quality sensor (23), a stirrer (24), a sludge discharge valve (25), a second water quality sensor (26), and a second water pump (27); the dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium aluminum sulfate, and polyaluminum chloride;

[0030] The photo-ozone synergistic catalytic reaction chamber (3) includes a precision aeration disc (31), a transparent lampshade (32) and a light source (33), a catalytic chamber and a partition (35), a third water quality sensor (36), and a sunlight collector (37). The natural light collector (37) includes a Fresnel lens (371), a light guide (372), and a diffuser (373). The light source (33) is one or more of a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, and a halogen lamp. The catalytic chamber in the catalyst chamber and partition (35) contains the carbon nitride composite biochar catalyst (34) as described in claim 1, and the pore diameter of the partition is smaller than the diameter of the catalyst. The sunlight collector (37) can be used to concentrate sunlight to excite the catalyst on sunny days, and the light source is provided by the transparent lampshade (32) and the light source (33) on cloudy days and at night.

[0031] The central control room (4) includes a solar panel (41), a control panel (42), a battery (43), an integrated air-source ozone generator (44), and an exhaust gas treatment device (45). The dosing pump (21), the first water pump (22), the stirrer (24), the first water quality sensor (23), the second water quality sensor (26), the second water pump (27), the transparent lampshade (32) and light source (33), the third water quality sensor (36), the battery (43), and the integrated air-source ozone generator (44) are connected to the control panel, which has a built-in control system, display system, and network system. The solar panel (41) is connected to the battery (43) and can use sunlight to generate electricity to power the equipment.

[0032] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0033] S1 The carbon nitride composite biochar material of the present invention utilizes alkali metal / alkaline earth metal hydroxide doping of carbon nitride during the preparation process. Through metal ion anchoring and surface hydroxylation modification, a salt ion-resistant shielding layer is formed, effectively inhibiting Cl-. - SO4 2- The poisoning effect of salinity on active sites simultaneously accelerates charge carrier separation and enhances redox potential. By combining carbon nitride with biochar materials, the electron transfer and recombination mechanisms between the two materials are utilized to improve catalytic activity and reduce costs. Furthermore, a binder is used to load carbon nitride-biochar composite materials onto alumina microspheres, thereby extending service life and facilitating recycling.

[0034] S2 offers an integrated wastewater treatment system designed to address challenges such as saline wastewater treatment. It combines a coagulation and sedimentation chamber, a photo-ozone synergistic catalytic reaction chamber, and a solar energy collection system. Solar panels and Fresnel lens collectors ensure efficient utilization of solar energy, reducing energy consumption. The equipment is mobile and features intelligent central control for real-time parameter adjustment, making it suitable for treating saline wastewater in chemical industrial parks, saving manpower, resources, and operating costs. Attached Figure Description

[0035] Figure 1 A flowchart of the preparation method provided for an example of the present invention;

[0036] Figure 2 Device diagram provided for an example of the present invention;

[0037] Figure 3 Disassembly diagrams of various parts of the device provided for examples of the present invention;

[0038] Figure 4 To investigate the removal efficiency of carbon nitride nanotubes doped with different concentrations of NaOH solution for the novel pollutant p-nitrophenol (PNP) in an ozone catalytic oxidation coupled photocatalytic system; Detailed Implementation

[0039] Example 1: Preparation method of carbon nitride composite biochar material

[0040] Melamine and cyanuric acid (molar ratio 1:1) were dissolved separately in aqueous solutions. The cyanuric acid solution was added dropwise to the melamine solution. The resulting precipitate was subjected to a hydrothermal reaction at 180℃ for 8 hours, collected, and dried. The precipitate was then calcined at 520℃ for 4 hours under a nitrogen atmosphere (2 mL / min) to obtain tubular carbon nitride. 0.5 g of carbon nitride was mixed evenly with 0.15 mol / L NaOH solution and subjected to a hydrothermal reaction at 150℃ for 18 hours to obtain functional group-doped carbon nitride nanotubes. *Ulva prolifera* was ground through a 200-mesh sieve and mixed evenly with KOH at a mass ratio of 1:2 in an aqueous solution. After soaking, the mixture was washed with water and dried. The mixture was then calcined at 650℃ for 2 hours under a nitrogen atmosphere (2 mL / min). The alkali-modified product was added to 1 mol / L hydrochloric acid for 1 hour of acid leaching, followed by acid heat treatment for 1 hour. After natural cooling, the mixture was washed three times with ethanol and finally washed with deionized water until the solution was neutral to obtain biochar material. Functional group-doped carbon nitride nanotubes and biochar were mixed uniformly in an aqueous solution at a mass ratio of 1:4. After drying, the mixture was calcined at 300℃ for 1 h under a nitrogen atmosphere (2 mL / min) to obtain carbon nitride composite biochar material. 0.55 g of the carbon nitride composite biochar material was taken, epoxy resin binder was added, and the mixture was stirred into a paste. Granulation was performed using a spherical mold and alumina spheres. The mold was frozen for 1 h to set the shape before demolding. The demolded product was dried at 180℃ for 3 h to obtain carbon nitride composite biochar spheres.

[0041] Example 2: Integrated reactor device of pre-coagulation sedimentation tank + ozone photocatalysis

[0042] Embodiment 2 of the invention provides a device of "pre-coagulation sedimentation tank + ozone photocatalysis integrated reactor", which specifically includes the following: box body (1), coagulation sedimentation chamber (2), photo-ozone synergistic catalytic reaction chamber (3), and central control room (4);

[0043] The coagulation sedimentation chamber (2) includes a dosing pump (21), a first water pump (22), a first water quality sensor (23), a stirrer (24), a sludge discharge valve (25), a second water quality sensor (26), and a second water pump (27); the dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium aluminum sulfate, and polyaluminum chloride;

[0044] The photo-ozone synergistic catalytic reaction chamber (3) includes a precision aeration disc (31), a transparent lampshade (32) and a light source (33), a catalytic chamber and a partition (35), a third water quality sensor (36), and a sunlight collector (37). The natural light collector (37) includes a Fresnel lens (371), a light guide (372), and a diffuser (373). The light source (33) is one or more of a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, and a halogen lamp. The catalytic chamber in the catalyst chamber and partition (35) contains the carbon nitride composite biochar catalyst (34) as described in claim 1, and the pore diameter of the partition is smaller than the diameter of the catalyst. The sunlight collector (37) can be used to concentrate sunlight to excite the catalyst on sunny days, and the light source is provided by the transparent lampshade (32) and the light source (33) on cloudy days and at night.

[0045] The central control room (4) includes a solar panel (41), a control panel (42), a battery (43), an integrated air-source ozone generator (44), and an exhaust gas treatment device (45). The dosing pump (21), the first water pump (22), the stirrer (24), the first water quality sensor (23), the second water pump (27), the second water quality sensor (26), the transparent lampshade (32) and light source (33), the third water quality sensor (36), the battery (43), and the integrated air-source ozone generator (44) are connected to the control panel, which has a built-in control system, display system, and network system. The solar panel (41) is connected to the battery (43) and can use sunlight to generate electricity to power the equipment.

[0046] Experimental Example 1

[0047] The carbon nitride composite biochar material prepared in Example 1 was used for performance testing of an ozone catalytic oxidation coupled photocatalytic system. Using PNP as the target pollutant, the activity of the above material in the ozone catalytic oxidation coupled photocatalytic system was tested after slow adsorption. The results are as follows: Figure 4 As shown. By Figure 4 It can be seen that the material prepared using 0.15 mol / L NaOH solution has the highest removal rate of PNP. When the initial concentration of PNP is 50 mg / L, the removal rate of PNP can reach 98.30% after 60 min.

[0048] The applicant declares that the above embodiments are used to illustrate the detailed operation and process flow of the present invention, but are not limited to the above detailed operation and process flow. Those skilled in the art should understand that equivalent substitutions of raw materials and processes, additions of auxiliary components, and selection of specific methods for the products of the present invention all fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a carbon nitride composite biochar catalytic material for treating saline wastewater, mainly comprising the following steps: Preparation of S1 tubular carbon nitride: A certain mass of melamine was added to water and ultrasonically heated until completely dissolved to obtain solution I; a certain mass of cyanuric acid was added to water and ultrasonically heated until completely dissolved to obtain solution II; solution II was added dropwise to solution I in a boiling water bath and heated and stirred continuously. After washing with water, precipitate I was obtained; precipitate I was subjected to a hydrothermal reaction in a hydrothermal reactor, and the product obtained after the reaction was collected and freeze-dried to obtain precipitate II; Precipitate II was calcined under a nitrogen atmosphere to obtain product I; Preparation of S2 functional group-doped carbon nitride: A certain mass of product I is reacted with a certain concentration of dopant in a hydrothermal reactor. The product obtained after the reaction is collected and dried to obtain product II. The dopant includes one or more of NaOH, KOH, LiOH, Ca(OH)2, and Mg(OH)2. Preparation of S3 biochar: After grinding and sieving the biomass, it was mixed evenly with alkali in an aqueous solution at a certain mass ratio and soaked. After drying, it was calcined under a nitrogen atmosphere. The product was then post-treated, collected, and dried to obtain product III. Preparation of S4 product IV: Product II was mixed with biochar at a certain mass ratio, and the mixture was ultrasonically stirred in an aqueous solution until homogeneous. The resulting product was collected and dried to obtain precipitate III. Precipitate III was then calcined under a nitrogen atmosphere to obtain product IV. Preparation of S5 carbon nitride composite biochar catalytic material: Weigh a certain mass of product IV, add a binder, stir with a glass rod to form a paste, and prepare a spherical mold and alumina spheres for granulation; after freezing and shaping the mold, demold and dry at a certain temperature to obtain product V.

2. The method for preparing the carbon nitride composite biochar catalytic material for saline wastewater treatment according to claim 1, characterized in that, In step S1, the molar ratio of melamine to cyanuric acid is 1:0.5-1.5; the ultrasonic time is 0.2-0.5 h, and the ultrasonic frequency is 20-60 kHz; the heating temperature is 60-90 ℃; the hydrothermal reaction temperature is 140-200 ℃, and the hydrothermal reaction time is 4-12 h; the nitrogen flow rate is 2-5 mL / min, the calcination reaction temperature is 400-800 ℃, the heating rate is 2-15 ℃ / min, and the calcination reaction time is 2-6 h.

3. The method for preparing the carbon nitride composite biochar catalytic material for saline wastewater treatment according to claim 1, characterized in that, In step S2, the mass of tubular carbon nitride is 0.5-2.5 g; the concentration of the dopant is 0.1, 0.15, or 0.2 mol / L; the dopant includes one or more of NaOH, KOH, LiOH, Ca(OH)2, and Mg(OH)2; the hydrothermal reaction temperature is 120-180 ℃, the hydrothermal reaction time is 14-20 h; and the drying temperature is 40-80 ℃.

4. The method for preparing the carbon nitride composite biochar catalytic material for saline wastewater treatment according to claim 1, characterized in that, In step S3, the biomass includes one or more of the following: seaweed, algae, straw, fruit shells, and sawdust; the alkali includes one or more of the following: potassium hydroxide and ammonia water; the mass ratio of biomass to alkali is 1:1-4; the soaking time is 4-12 h; the drying temperature is 40-80 ℃; the nitrogen flow rate is 2-5 mL / min; the calcination reaction temperature is 500-800 ℃; the heating rate is 2-15 ℃ / min; and the calcination reaction time is 1-6 h. The post-treatment includes acid soaking in 1-5 mol / L hydrochloric acid for 1-3 h, acid heat treatment at 80-100 ℃ for 1-3 h, alcohol washing 3-5 times, and water washing until the solution is neutral.

5. The method for preparing the carbon nitride composite biochar catalytic material for saline wastewater treatment according to claim 1, characterized in that, In step S4, the mass ratio of carbon nitride to biochar is 1:1-5; the ultrasonic time is 0.2-0.5 h, and the ultrasonic frequency is 20-60 kHz; the drying temperature is 40-80 ℃; the nitrogen flow rate is 2-5 mL / min; the calcination reaction temperature is 300-600 ℃, the heating rate is 2-15 ℃ / min, and the calcination reaction time is 1-5 h.

6. The method for preparing the carbon nitride composite biochar catalytic material for saline wastewater treatment according to claim 1, characterized in that, In step S5, the mass of the carbon nitride composite biochar catalyst is 0.5-2.5 g; the binder includes one or more of epoxy resin, waterborne polyurethane, acrylate, and phenolic resin; the mold is placed in a refrigerator for freezing and shaping for 1-3 hours before demolding; the demolded product is dried at 160-200 ℃ for 1-5 hours.

7. An integrated wastewater treatment device consisting of a pre-coagulation sedimentation tank and ozone photocatalysis, comprising a tank (1), a coagulation sedimentation chamber (2), a photo-ozone synergistic catalytic reaction chamber (3), and a central control room (4). The coagulation sedimentation chamber (2) includes a dosing pump (21), a first water pump (22), a first water quality sensor (23), a stirrer (24), a sludge discharge valve (25), a second water quality sensor (26), and a second water pump (27); the dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium aluminum sulfate, and polyaluminum chloride; The photo-ozone synergistic catalytic reaction chamber (3) includes a precision aeration disc (31), a transparent lampshade (32) and a light source (33), a catalytic chamber and a partition (35), a third water quality sensor (36), and a natural light collector (37). The natural light collector (37) includes a Fresnel lens (371), a light guide (372), and a diffuser (373). The light source (33) is one or more of a xenon lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, and a halogen lamp. The catalytic chamber and partition (35) contain a carbon nitride composite biochar catalytic material (34) prepared by the preparation method described in claim 1. The pore diameter of the partition is smaller than that of the catalyst. The natural light collector (37) can be used to concentrate sunlight to excite the catalyst on sunny days, and the transparent lampshade (32) and the light source (33) provide the light source on cloudy days and at night. The central control room (4) includes a solar panel (41), a control screen (42), a battery (43), an integrated air source ozone generator (44), and an exhaust gas treatment device (45). The dosing pump (21), the first water pump (22), the stirrer (24), the first water quality sensor (23), the second water quality sensor (26), the second water pump (27), the transparent lampshade (32) and the light source (33), the third water quality sensor (36), the battery (43), and the integrated air source ozone generator (44) are connected to the control screen, which has a built-in control system, display system, and network system. The solar panel (41) is connected to the battery (43) and can use sunlight to generate electricity to power the equipment.

8. The integrated wastewater treatment device of "pre-coagulation sedimentation tank + ozone photocatalysis" according to claim 7, characterized in that, The saline wastewater is pumped into the coagulation sedimentation chamber (2) by the first water pump (22), and sodium carbonate and magnesium oxide are added by the dosing pump (21). After mixing by the agitator (24), flocs are formed, and high concentrations of Cl are initially precipitated. - SO4 2- And suspended solids; the settled sludge is discharged through the sludge discharge valve (25), and the supernatant is pumped into the photo-ozone synergistic catalytic reaction chamber (3) by the second water pump (27) through the sawtooth overflow weir; the first water quality sensor (23) and the second water quality sensor (26) monitor the pH, turbidity and salinity in real time and feed back to the central control room (4) to dynamically adjust the dosage of the reagent; the pretreated wastewater enters the photo-ozone synergistic catalytic reaction chamber (3), the integrated air source ozone generator (44) generates O3 gas, which is evenly dispersed into the wastewater through the precision aeration disc (31), and the tail gas is discharged after being treated by the tail gas treatment device (45); at the same time, the natural light collector (3 7) The sunlight is focused by the Fresnel lens (371) and transmitted to the diffuser (372) to uniformly irradiate the carbon nitride composite biochar catalyst material (34) in the catalyst chamber, thereby stimulating the catalyst to generate ·OH active species to degrade organic matter. The partition is used to separate and recover the catalyst. The third water quality sensor (36) detects the COD and TOC of the effluent and uploads the data to the control panel (42) to adjust the light source intensity, O3 dosage and hydraulic residence time. The solar panel (41) and the battery (43) work together to provide power. On cloudy days, the power source is automatically switched to the light source (33) to ensure continuous operation for 24 hours.

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