Carbon nitride composite biochar catalytic material for salt-containing wastewater treatment and device thereof

Abstract

The invention relates to a carbon nitride composite biochar catalytic material for salt-containing wastewater treatment and a matched device thereof. According to the material, carbon nitride is modified by adopting a functional group doping strategy, an anti-salt ion shielding layer is constructed through surface hydroxylation modification, the poisoning effect of Cl <->, SO4 < 2-> and other salts on active sites is effectively inhibited, meanwhile, the light absorption range is widened, and the oxidation capacity is enhanced. The biochar composite carbon nitride material with dual functions of adsorption and catalysis is utilized, so that the catalytic capability is further improved. The integrated sewage treatment equipment adopting the front coagulative precipitation tank and the ozone photocatalysis is combined with the advantages of physical, chemical and advanced oxidation technologies, and pollutants in the high-salinity wastewater are efficiently removed through a multi-stage synergistic effect.

Description

Technical Field

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

[0002] With the increasing ecological risks of emerging contaminants (ECs) in industrial park wastewater and the increasing complexity of water quality, traditional treatment technologies face bottlenecks such as low removal efficiency and weak resistance to salt interference. Although heterogeneous ozone catalytic oxidation (HCO) is effective in degrading ECs, it is limited by the low solubility of O3, short transmission distance, and problems of catalyst deactivation and formation of toxic by-products caused by salt ions (such as Cl-); the photocatalytic system realizes the degradation of pollutants through the redox reaction driven by photo-generated electron-hole pairs, but it is difficult to operate stably due to problems such as high carrier recombination rate, accumulation of intermediate products, and mass transfer resistance at the reaction interface. Therefore, constructing an ozone catalytic oxidation coupled photocatalytic system has become the key to breaking through the limitations of single technologies, and its core lies in designing the structure of the catalytic material and regulating its catalytic activity.

[0003] Carbon nitride exhibits excellent catalytic activity in the ozone catalytic oxidation coupled photocatalytic system, but its high photo-generated carrier recombination rate, weak conductivity, and narrow photo-response range restrict its practical application. Through synergistic modification strategies such as band engineering regulation, heteroatom doping, and functional group modification (such as introducing alkali / alkaline earth metal hydroxides), electron injection enhancement, directional construction of surface hydroxyl active sites, and optimization of charge separation can be achieved. At the same time, the material is endowed with the ability to resist salt ions (Cl - 、SO4 2- ) interference, and the stability of catalytic active sites is maintained through electrostatic repulsion and stable pore structure, significantly improving the treatment performance of high-salt wastewater. Biochar (BC) can form conjugate bonds with carbon nitride under medium-temperature conditions, and regulate the spin density and electron configuration through nitrogen-rich components to strengthen interfacial charge transfer. In addition, aiming at problems such as catalyst particle agglomeration, difficult separation, and inability to be recycled, a binder is used to load the carbon nitride composite biochar material on alumina spheres, while improving the catalytic activity.

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

[0005] Aiming at the problems of existing catalysts such as agglomeration, difficult separation, and inability to be recycled, a preparation method of a carbon nitride composite biochar catalytic material for treating saline wastewater is provided. The carbon nitride is modified by a functional group doping strategy, which broadens the light absorption range and enhances the oxidation ability. At the same time, a biochar with dual functions of adsorption and catalysis is combined with the carbon nitride material to improve its catalytic ability. In addition, the present invention adopts an integrated sewage treatment device of "pre-coagulation sedimentation tank + ozone photocatalysis", which combines the advantages of physical, chemical, and advanced oxidation technologies, and realizes the efficient removal of pollutants in high-salt wastewater through multi-stage synergistic effects.

[0006] One aspect of the present invention provides a carbon nitride composite biochar catalytic material for treating saline wastewater. The preparation steps of this method are as follows:

[0007] S1 Preparation of tubular carbon nitride:

[0008] Add a certain mass of melamine to water, ultrasonically heat until completely dissolved to obtain solution I; add a certain mass of cyanuric acid to water, ultrasonically heat until completely dissolved to obtain solution II; dropwise add solution II to solution I in a boiling water bath, and continue to heat and stir. After washing with water, precipitate I is obtained; precipitate I is subjected to a hydrothermal reaction in a hydrothermal reaction kettle, and the obtained product after the reaction is collected and freeze-dried to obtain precipitate II; precipitate II is calcined in a nitrogen atmosphere to obtain product I.

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

[0010] A certain mass of product I and a doping agent with a certain concentration are subjected to a hydrothermal reaction in a hydrothermal reaction kettle. The obtained product after the reaction is collected and dried to obtain product II.

[0011] S3 Preparation of biochar:

[0012] The biomass is ground and sieved, then mixed and soaked with an alkali in an aqueous solution according to a certain mass ratio. After drying, it is calcined in a nitrogen atmosphere, and the product is post-treated, collected, and dried to obtain product III.

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

[0014] The carbon nitride and the biochar are mixed according to a certain mass ratio, ultrasonically stirred evenly in an aqueous solution, and then the obtained product is collected and dried to obtain precipitate III. Precipitate III is calcined in a nitrogen atmosphere to obtain product IV.

[0015] S5 Preparation of biochar spheres:

[0016] Weigh a certain mass of carbon nitride composite biochar material, add a binder, stir it into a mud with a glass rod, and prepare a spherical mold and alumina balls for granulation. After freezing and shaping the mold, demold it and dry it at a certain temperature to obtain Product V.

[0017] Further, in the step S3, the specific operation steps for grinding and sieving the biomass are as follows: After washing and drying the biomass, grind it into a powder, and sieve the obtained powder through a 200-mesh sieve for standby.

[0018] Further, in the step S3, the specific post-treatment steps are as follows: Add the product to 1 moL / L hydrochloric acid for acid leaching for 1 - 3 h, then perform acid heat treatment at 80 - 100 °C for 1 - 3 h. After natural cooling, wash it with ethanol 3 - 5 times, and finally wash it with deionized water until the solution is neutral.

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

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

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

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

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

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

[0025] Optionally, in steps S1, S3, and S4, the nitrogen gas 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 ultrasonic time is 0.2 - 0.5 h, and the ultrasonic frequency is 20 - 60 kHz.

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

[0028] On the other hand, the present invention provides an integrated sewage treatment device of "pre - coagulation sedimentation tank + ozone photocatalysis" for treating saline wastewater, including a box body (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 chemical 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 chemical dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium alum, and polyaluminum chloride;

[0030] The photo - ozone synergistic catalytic reaction chamber (3) includes a precision aeration disk (31), a transparent lamp cover (32) and a light source (33), a catalyst 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 tube (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 catalyst chamber in the catalyst chamber and partition (35) contains the carbon nitride composite biochar catalyst (34) as claimed in claim 1, and the diameter of the partition gap is smaller than the diameter of the catalyst; the sunlight collector (37) can be used to collect sunlight on sunny days to excite the catalyst, and on cloudy days and at night, the light source is provided by the transparent lamp cover (32) and the light source (33);

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

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

[0033] S1 In the preparation process of the carbon nitride composite biochar material of the present invention, alkali metal / alkaline earth metal hydroxides are used to dope carbon nitride, and an anti-salt ion shielding layer is formed through metal ion anchoring and surface hydroxylation modification, effectively inhibiting the poisoning effect of salts such as Cl - , SO4 2- on the active sites, while realizing the accelerated separation of charge carriers and the enhancement of redox potential. The carbon nitride and the biochar material are compounded, and the catalytic activity is improved and the cost is reduced by using the electron transfer and compounding mechanism between the carbon nitride and the biochar. At the same time, a binder is used to load the carbon nitride composite biochar material on the alumina balls, thereby extending the service life and facilitating recycling.

[0034] S2 In view of problems such as saline wastewater, an integrated sewage treatment device is provided, which integrates a coagulation sedimentation chamber, a photo-ozone synergistic catalytic reaction chamber, and a solar energy collection system. The solar panel and the Fresnel lens collector achieve efficient utilization of light energy and reduce energy consumption. The device can be deployed mobile, and the intelligent central control can adjust parameters in real time, which is suitable for the treatment of saline wastewater in chemical industrial parks, saving manpower, material resources, and operation costs. Description of the Drawings

[0035] Figure 1 It is a flow chart of the preparation method provided by an embodiment of the present invention;

[0036] Figure 2 It is a device diagram provided by an embodiment of the present invention;

[0037] Figure 3 It is an exploded view of each part of the device provided by an embodiment of the present invention;

[0038] Figure 4 It is the removal effect of nitrophenol (PNP), a new pollutant, by carbon nitride nanotubes doped with different concentrations of NaOH solution in an ozone catalytic oxidation coupled photocatalytic system; Detailed Embodiments

[0039] Example 1, Preparation Method of Carbon Nitride Composite Biochar Material

[0040] Melamine and cyanuric acid (molar ratio 1:1) were separately dissolved in an aqueous solution. The cyanuric acid solution was gradually added dropwise to the melamine solution. The obtained precipitate was hydrothermally reacted at 180 °C for 8 h, collected and dried, and then calcined at 520 °C for 4 h in a nitrogen (2 mL / min) atmosphere to obtain tubular carbon nitride. 0.5 g of carbon nitride was mixed evenly with 0.15 mol / L NaOH solution and hydrothermally reacted at 150 °C for 18 h to obtain functional group-doped carbon nitride nanotubes. Enteromorpha was ground and passed through a 200-mesh sieve, then mixed evenly with KOH in an aqueous solution at a mass ratio of 1:2 and soaked. After washing with water and drying, it was calcined at 650 °C for 2 h in a nitrogen (2 mL / min) atmosphere. The alkali-modified product was acid-leached in 1 mol / L hydrochloric acid for 1 h and then acid-heat-treated for 1 h. After natural cooling, it was washed three times with ethanol and finally washed with deionized water until the solution was neutral to obtain a biochar material. The functional group-doped carbon nitride nanotubes and the biochar were mixed evenly in an aqueous solution at a mass ratio of 1:4, dried, and then calcined at 300 °C for 1 h in a nitrogen (2 mL / min) atmosphere to obtain a carbon nitride composite biochar material. 0.55 g of the carbon nitride composite biochar material was taken, an epoxy resin binder was added, stirred into a mud, and granulated using a spherical mold and alumina balls. The mold was placed in a refrigerator and frozen for shaping for 1 h and then demolded; the demolded product was dried at 180 °C for 3 h to obtain carbon nitride composite biochar balls.

[0041] Example 2, "Pre-coagulation Sedimentation Tank + Ozone Photocatalytic Integrated Reactor" Device

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

[0043] The coagulation sedimentation chamber (2) includes a chemical 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 chemical dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium alum, and polyaluminum chloride;

[0044] The photo-ozone synergistic catalytic reaction chamber (3) includes a precision aeration disc (31), a transparent lamp cover (32), a light source (33), a catalytic chamber and a partition (35), a third water quality sensor (36), and a solar collector (37). The natural light collector (37) includes a Fresnel lens (371), a light guide tube (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 the partition (35) contains the carbon nitride composite biochar catalyst (34) described in claim 1, and the diameter of the partition gap is smaller than the diameter of the catalyst; the solar collector (37) can be used to collect sunlight on sunny days to excite the catalyst, and the transparent lamp cover (32) and the light source (33) provide the light source on cloudy days and at night;

[0045] The central control room (4) includes a solar panel (41), a control panel (42), a storage 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 lamp cover (32), the light source (33), the third water quality sensor (36), the storage battery (43), and the integrated air source ozone generator (44) are connected to the control panel, and the control panel is built with a control system, a display system, and a network system. The solar panel (41) is connected to the storage battery (43), and can generate electricity using sunlight to supply power to the equipment.

[0046] Experimental Example 1

[0047] The carbon nitride composite biochar material prepared in Example 1 was used for the performance test of the ozone catalytic oxidation coupled photocatalytic system. The experiment used PNP as the target pollutant, and tested the activity of the above materials in the ozone catalytic oxidation coupled photocatalytic system after slow adsorption, and the results are as Figure 4 shown. It can be Figure 4 seen that the material prepared with 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% in 60 min.

[0048] The applicant declares that the above embodiments are used to illustrate the detailed operations and process flows of the present invention, but are not limited to the above detailed operations and process flows. Those skilled in the relevant technical fields should understand that the equivalent substitution of each raw material and process of the products of the present invention, the addition of auxiliary components, and the selection of specific methods all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a carbon nitride composite biochar catalytic material for treating saline wastewater mainly includes the following steps: S1 Preparation of tubular carbon nitride: Add a certain mass of melamine to water, ultrasonically heat until completely dissolved to obtain solution I; add a certain mass of cyanuric acid to water, ultrasonically heat until completely dissolved to obtain solution II; dropwise add solution II to solution I in a boiling water bath, and continue heating and stirring. After washing with water, obtain precipitate I; carry out hydrothermal reaction on precipitate I in a hydrothermal reaction kettle. Collect the product obtained after the reaction and freeze-dry to obtain precipitate II; Carry out a calcination reaction on precipitate II in a nitrogen atmosphere to obtain product I. S2 Preparation of functional group-doped carbon nitride: Carry out a hydrothermal reaction on a certain mass of product I and a doping agent with a certain concentration in a hydrothermal reaction kettle. Collect the product obtained after the reaction and dry it to obtain product II. S3 Preparation of biochar: Grind and screen the biomass, mix it evenly with an alkali in an aqueous solution according to a certain mass ratio and soak it. After drying, carry out a calcination reaction in a nitrogen atmosphere, carry out post-treatment on the product, collect it and dry it to obtain product III. S4 Preparation of carbon nitride composite biochar material: Mix carbon nitride and biochar according to a certain mass ratio, ultrasonically stir evenly in an aqueous solution, then collect the obtained product and dry it to obtain precipitate III. Carry out a calcination reaction on precipitate III in a nitrogen atmosphere to obtain product IV. S5 Preparation of biochar spheres: Weigh a certain mass of the carbon nitride composite biochar material, add a binder, stir it into a paste with a glass rod, and prepare a spherical mold and alumina balls for granulation. After freezing and shaping the mold, demold it and dry it at a certain temperature to obtain product V.

2. The preparation method of the carbon nitride composite biochar catalytic material applied to saline wastewater treatment according to claim 1, characterized in that, In the 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, the ultrasonic frequency is 20 - 60 kHz; the heating temperature is 60 - 90 °C; the hydrothermal reaction temperature is 140 - 200 °C, the hydrothermal reaction time is 4 - 12 h; the nitrogen flow rate is 2 - 5 mL / min, the calcination reaction temperature is 400 - 800 °C, the heating rate is 2 - 15 °C / min, and the calcination reaction time is 2 - 6 h.

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

4. The preparation method of the carbon nitride composite biochar catalytic material applied to the treatment of saline wastewater according to claim 1, characterized in that, In the step S3, the biomass includes one or more of Enteromorpha prolifera, seaweed, straw, fruit shell and wood chip; the alkali includes one or more of potassium hydroxide, sodium carbonate, sodium bicarbonate and ammonia water; the mass ratio of the biomass to the alkali is 1:1 - 4, and the soaking time is 4 - 12 h; the drying temperature is 40 - 80 °C; the nitrogen gas flow rate is 2 - 5 mL / min, the calcination reaction temperature is 500 - 800 °C, the heating rate is 2 - 15 °C / min, and the calcination reaction time is 1 - 6 h; the post-treatment includes acid leaching with 1 - 5 moL / L hydrochloric acid for 1 - 3 h, acid heat treatment at 80 - 100 °C for 1 - 3 h, alcohol washing for 3 - 5 times and water washing until the solution is neutral.

5. The preparation method of the carbon nitride composite biochar catalytic material applied to saline wastewater treatment according to claim 1, characterized in that, In the 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 °C; the nitrogen gas flow rate is 2 - 5 mL / min, the calcination reaction temperature is 300 - 600 °C, the heating rate is 2 - 15 °C / min, and the calcination reaction time is 1 - 5 h.

6. The preparation method of the carbon nitride composite biochar catalytic material applied to the treatment of saline wastewater according to claim 1, characterized in that, In the step S5, the mass of the carbon nitride composite biochar material is 0.5 - 2.5 g; the binder includes one or more of epoxy resin, waterborne polyurethane, acrylate and phenolic resin; the mold is put into the refrigerator for freezing and shaping for 1 - 3 h and then demolded; the demolded product is dried at 160 - 200 °C for 1 - 5 h.

7. An integrated sewage treatment device of "pre - coagulation sedimentation tank + ozone photocatalysis" applied to the treatment of saline wastewater by implementing the method as claimed in claim 1, comprising a box body (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 chemical 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 chemical dosing pump (21) can be used to add one or more of sodium carbonate, aluminum hydroxide, magnesium oxide, potassium alum and polyaluminum chloride; The photo - ozone synergistic catalytic reaction chamber (3) includes a precision aeration disc (31), a transparent lamp shade (32) and a light source (33), a catalyst chamber and a partition plate (35), a third water quality sensor (36), and a solar collector (37). The natural light collector (37) includes a Fresnel lens (371), a light guide tube (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 catalyst chamber in the catalyst chamber and partition plate (35) contains the carbon nitride composite biochar catalyst (34) as claimed in claim 1, and the diameter of the partition plate gap is smaller than the diameter of the catalyst; the solar collector (37) can be used to gather sunlight on sunny days to excite the catalyst, and on cloudy days and at night, the light source is provided by the transparent lamp shade (32) and the light source (33); The central control room (4) comprises a solar panel (41), a control panel (42), a storage 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 agitator (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 storage battery (43), and the integrated air source ozone generator (44) are connected to the control panel, and the control panel has a built-in control system, a display system, and a network system. The solar panel (41) is connected to the storage battery (43), and solar power generation can be used to power the equipment.

8. The integrated sewage treatment device of "pre - coagulation sedimentation tank + ozone photocatalysis" applied to the treatment of saline wastewater 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 chemicals such as sodium carbonate and magnesium oxide are added by the chemical dosing pump (21). After mixing through the agitator (24), flocs are formed, and high-concentration Cl - , SO4 2- and suspended solids are preliminarily precipitated; the precipitated sludge is discharged through the sludge discharge valve (25), and the supernatant passes through the serrated overflow weir and is pumped into the photo-ozone synergistic catalytic reaction chamber (3) by the second water pump (27). The first water quality sensor (23) and the second water quality sensor (26) monitor the pH, turbidity and salinity in real time and feedback to the central control room (4) to dynamically adjust the chemical dosing amount. 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 sunlight collector (37) uses a Fresnel lens (371) to focus sunlight, which is transmitted to the diffuser (373) through the light guide (372) to evenly illuminate the carbon nitride composite biochar catalyst (34) in the catalyst chamber, stimulating the catalyst to produce active species such as OH to degrade organic matter. The partition can separate and recycle the catalyst. The third water quality sensor (36) detects the COD and TOC of the water, and the data is uploaded to the control panel (42), which is linked to adjust the light source intensity, O3 dosage and hydraulic retention time; the solar panel (41) and the battery (43) are coordinated to supply power, and it automatically switches to the artificial light source (33) on cloudy days to ensure 24-hour continuous operation.

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