Process for treating high-salinity wastewater in coal chemical industry

Abstract

The invention discloses a coal chemical industry high-salinity wastewater treatment process, and belongs to the technical field of water treatment. According to the present invention, the pretreatment, deep oxidation, desalination and sterilization integrated treatment scheme is adopted, and the core advantage is that the organic matter degradation and the salt removal can be efficiently considered; in the deep oxidation, a novel rare earth-based high-entropy composite Janus structure nanoparticle catalyst is adopted, and on the basis of a cooling crystallization strategy guided by a carbon-affinity difference, by combining electrostatic spinning, graphitization and interface regulation and control, biphase oriented growth and heterogeneous integration are realized. The asymmetric structure of the Janus material endows the Janus material with unique hydrophilic-hydrophobic wettability, challenges of complex components, containing oil stains and surfactants and the like in coal chemical industry high-salinity wastewater can be efficiently handled, a stable single crystal phase formed by multiple metal elements can effectively resist erosion of high-salinity, high-temperature and high-pressure working conditions, and the COD removal efficiency of an ozone catalysis process is synergistically improved; and carrying out multi-effect evaporation desalination, activated carbon adsorption and ultraviolet sterilization on the deeply oxidized wastewater to obtain water meeting the emission standard.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a coal chemical high-salinity wastewater treatment process. BACKGROUND

[0002] Coal chemical high-salinity wastewater is one of the key pollution sources generated in the production process of the coal chemical industry, and has the characteristics of complex water quality and difficult treatment. The wastewater has extremely high salt content, with TDS (total dissolved solids) usually exceeding 10,000 mg / L, and even reaching more than 50,000 mg / L; the pollutant composition is complex, containing toxic and harmful substances such as phenols, cyanide, polycyclic aromatic hydrocarbons and heterocyclic compounds; at the same time, the COD (chemical oxygen demand) is generally higher than 1,000 mg / L, and the biodegradability is poor, with a B / C ratio of less than 0.2.

[0003] Since conventional biochemical treatment cannot directly degrade this type of wastewater, and physical adsorption and membrane separation technologies cannot completely remove organic pollutants, ozone catalytic oxidation technology has become one of the key technologies for treating such high-salinity wastewater, as it can efficiently decompose refractory organic matter and significantly improve the biodegradability of wastewater.

[0004] A coal chemical wastewater treatment process is disclosed in Chinese Patent No. CN106116011B. The invention first treats the organic wastewater in coal chemical wastewater by a deaminated phenol treatment process, then by biochemical treatment, followed by concentration treatment, and finally by concentrated brine treatment to obtain salt-containing materials. The deaminated phenol treatment process includes a deacidification and deamination process, an extraction process, a solvent removal process, a solvent recovery process, a waste liquid separation system, a solvent storage process, and an alkali preparation process. This scheme realizes zero discharge of sewage through separate treatment and cascade reuse. However, under the premise that the process design relies on the classification treatment of organic wastewater and salt-containing wastewater, if the actual water conditions deviate from the design assumptions, it is easy to lead to a decrease in treatment efficiency. The deaminated phenol treatment process has a high removal rate for single phenols, but coal chemical wastewater often contains multiple phenols, heterocyclic organic matter such as naphthol and pyridine, and other substances. These substances are difficult to be effectively extracted by conventional extraction solvents, resulting in COD of the waste liquid after deaminated phenol treatment still being >1,000 mg / L, and subsequent biochemical treatment load increasing sharply, leading to problems such as sludge bulking and non-compliance of effluent. SUMMARY

[0005] In order to improve the efficiency of ozone catalysts in removing COD in high-salinity wastewater, the present application proposes a new solution to adapt to different production processes and application environments.

[0006] The present application aims to provide a coal chemical high-salinity wastewater treatment process. The technical scheme first filters the wastewater to remove large-particle impurities, protects the pump body and equipment used in the subsequent process, adds a coagulant for flocculation, and the filtered wastewater enters an oxidation tank, uses a new type of oxidant for catalytic oxidation with ozone, degrades complex organic matter in the wastewater, and finally enters a multi-effect evaporation tank for desalination. The condensed water is finally subjected to activated carbon adsorption and ultraviolet sterilization to kill microorganisms and prevent the growth of biological sludge in the pipeline. The final water reaches the discharge standard. The new catalyst used in the present application is a rare earth-based high-entropy composite Janus structure nanoparticle catalyst (rare earth-based high-entropy composite asymmetric amphiphilic catalyst). A high-entropy precursor solution is prepared by mixing cerium salt, europium salt, tungsten salt and other metal salts with PAN (polyacrylonitrile), and a nanofiber membrane is obtained by electrospinning. After graphitization treatment, a rare earth-based high-entropy composite Janus structure nanoparticle catalyst is obtained. The Janus structure has one hydrophilic side and one hydrophobic side, which can effectively deal with the challenges of complex composition, high salinity, oil stains and surfactants in coal chemical high-salinity wastewater, and enhance its adaptability and treatment effect in complex water quality environment.

[0007] In order to achieve the above purpose, the present application provides a coal chemical high-salinity wastewater treatment process, comprising: S1, start the wastewater lifting pump, control the water inflow, make the wastewater evenly enter the vibrating screen, and the filtered wastewater enters the sedimentation tank; S2, adjust the pH of the wastewater to 6.5~7.5, add a coagulant under stirring, promote flocculation by stirring, and the filtered wastewater enters the oxidation tank; S3, put catalyst into the oxidation tank, catalytic oxidation with ozone to degrade pollutants, and the filtered wastewater enters the evaporation tank; S4, the wastewater is desalted by multi-effect evaporation, the condensed water is adsorbed by activated carbon, enters the ultraviolet reactor for ultraviolet sterilization, and is filtered to obtain dischargeable water.

[0008] Preferably, in S1, the water inflow is 80~100m 3 / h, and the pressure is controlled at 0.2~0.4MPa.

[0009] Preferably, in S1, the aperture of the vibrating screen is 100~200 mesh, the frequency is controlled at 1500~3000 times / min, and the amplitude is 3~5mm.

[0010] Preferably, in S2, the coagulant is a polyaluminum chloride aqueous solution with a concentration of 10~15wt.%, and the addition amount of the coagulant is 100~200mg / L of wastewater.

[0011] Preferably, in S2, the stirring speed is 200~300rpm, and the stirring time is 2~5min.

[0012] Preferably, in S2, the stirring speed for promoting flocculation is 50-80 rpm, and the time is 5-10 min.

[0013] Preferably, in S2, the standing time is 30-60 min.

[0014] Preferably, in S3, the catalyst is a rare earth-based high-entropy composite Janus structure nanoparticle catalyst.

[0015] The application also provides a preparation method of the catalyst in S3, comprising: A1, adding cerium salt, europium salt, tungsten salt, manganese salt, other metal salt and PAN into DMF (N, N-dimethylformamide), stirring to obtain a high-entropy precursor solution, and the other metal salt is iron salt or cobalt salt; A2, the high-entropy precursor solution is dried by electrospinning to obtain a nanofiber membrane; A3, placing the nanofiber membrane in a chemical vapor deposition furnace for graphitization treatment: heating in an air atmosphere, switching to an argon atmosphere, holding, cooling and crystallizing to obtain a rare earth-based high-entropy composite Janus structure nanoparticle catalyst.

[0016] Preferably, in A1, the cerium salt is Ce(NO3)3·6H2O.

[0017] Preferably, in A1, the europium salt is Eu(NO3)3·6H2O.

[0018] Preferably, in A1, the tungsten salt is (NH4)6H2W 12 O 40 .

[0019] Preferably, in A1, the manganese salt is Mn(OAc)2·4H2O.

[0020] Preferably, in A1, the iron salt is Fe(NO3)3·9H2O.

[0021] Preferably, in A1, the cobalt salt is Co(NO3)2·6H2O.

[0022] Preferably, in A1, the mass-volume ratio of the cerium salt, europium salt, tungsten salt, manganese salt, Fe(NO3)3·9H2O, PAN and DMF is (80-180) mg:(60-120) mg:(40-70) mg:(20-60) mg:(60-120) mg:(1.2-1.9) g:15 mL.

[0023] Preferably, in A1, the mass-to-volume ratio of the cerium salt, europium salt, tungsten salt, manganese salt, Co(NO3)2·6H2O, PAN and DMF is (80~180) mg: (60~120) mg: (40~70) mg: (20~60) mg: (60~90) mg: (1.2~1.9) g: 15 mL.

[0024] Preferably, in A1, the stirring time is 10-12 hours.

[0025] Preferably, in A2, the electrospinning process parameters are: anode voltage of 15~16kV, cathode voltage of 1~2kV, needle tip-tin foil collector distance of 15~20cm; the drying temperature of 50~60℃, and the drying time of 10~12h.

[0026] Preferably, in A3, the heating temperature is 200~230℃ and the heating time is 3~4h.

[0027] Preferably, in A3, the heat preservation temperature is 800~1000℃, the heat preservation time is 3~5h, and the heating rate is 2℃ / min.

[0028] Preferably, in A3, the cooling crystallization temperature is 600~700℃, and the cooling rate is 2℃ / min.

[0029] Preferably, in step S3, the amount of catalyst used is (8~10) g / L wastewater.

[0030] Preferably, in step S4, the process and parameters of the multi-effect evaporation desalination include: the heating steam temperature for the first-effect evaporation is 120~130℃, and the operating pressure is 0.15~0.2MPa; the heating steam temperature for the second-effect evaporation is 100~110℃, and the operating pressure is 0.08~0.1MPa; and the heating steam temperature for the third-effect evaporation is 85~95℃, and the operating pressure is 0.03~0.05MPa.

[0031] Preferably, in step S4, the activated carbon adsorption process and parameters include: using a fixed-bed activated carbon adsorption column, and using granular coconut shell activated carbon with a specific surface area ≥1000 m². 2 / g, pore size 2~5nm, wastewater enters the activated carbon adsorption column at a flow rate of 5~8m / h, and residence time is 15~20min.

[0032] Preferably, in step S4, the parameters of the ultraviolet reactor are: the wavelength of the ultraviolet lamp is 254 nm, and the irradiance is 20~30 mJ / cm². 2 The flow rate of wastewater in the ultraviolet reactor is 1~2m / s.

[0033] Compared with the prior art, the beneficial effects of the present invention are reflected in: (1) In the wastewater oxidation process, this invention employs a rare earth-based high-entropy composite Janus structure nanoparticle catalyst to synergistically enhance ozone catalytic oxidation and improve wastewater treatment efficiency. Rare earth elements, with their unique electronic structure and excellent oxygen storage and release capabilities, combined with the synergistic effect of the high-entropy effect, can significantly reduce the activation energy and required temperature during the catalytic oxidation and degradation of organic matter. Simultaneously, the rare earth components also possess certain resistance to sulfur and halogen poisoning, effectively dispersing and passivating toxic substances in wastewater and improving catalyst stability. The nanoscale catalyst has a stable single-phase crystal structure composed of multiple metal elements, which endows the catalyst with excellent corrosion resistance, enabling it to better resist the erosion caused by complex components in high-salt wastewater and high-temperature, high-pressure process conditions, thereby delaying catalyst deactivation. By utilizing the difference in carbon affinity to induce preferential nucleation of W2C and driving epitaxial growth of the catalyst during subsequent cooling, a functional material with a Janus structure is ultimately formed. The structure is hydrophilic on one side and hydrophobic on the other, enabling it to effectively address the challenges of complex composition, high salt content, oil pollution, and surfactants in coal chemical high-salt wastewater, thus enhancing its adaptability and treatment effect in complex water environments.

[0034] (2) This invention targets high-salt and high-organic-content wastewater and adopts an integrated treatment scheme of pretreatment, deep oxidation, and desalination and sterilization. Its core advantage lies in its ability to efficiently balance organic matter degradation and salt removal. In the pretreatment stage, a vibrating screen and coagulant are used to efficiently remove suspended solids and colloids. In the deep oxidation stage, a novel rare-earth-based high-entropy composite Janus structure nanoparticle catalyst and ozone are used to synergistically and effectively degrade recalcitrant organic matter. In the desalination and sterilization stage, multi-effect evaporation, activated carbon adsorption, and ultraviolet sterilization are used to achieve dual control of salt and microorganisms, simultaneously solving the problems of water salinization caused by salt residue and environmental risks caused by excessive microorganisms. Attached Figure Description

[0035] Figure 1 This is a process flow diagram for treating high-salt wastewater from coal chemical industry.

[0036] Figure 2 This is a flowchart illustrating the preparation process of a rare-earth-based high-entropy composite Janus structure nanoparticle catalyst.

[0037] Figure 3 The COD removal rate of wastewater in Examples 4 to 6 and Comparative Examples 3 to 4 is given.

[0038] Figure 4 The removal rate of wastewater color in Examples 4 to 6 and Comparative Examples 3 to 4 is given.

[0039] Figure 5This is a TEM image of the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Example 3. Detailed Implementation

[0040] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0041] The main compounds used in the examples and comparative examples were all commercially available products and were not subjected to any further purification treatment.

[0042] Example 1 like Figure 2 As shown, a rare earth-based high-entropy composite Janus structure nanoparticle catalyst is prepared by the following method: A1. 86.85 mg of Ce(NO3)3·6H2O, 89.22 mg of Eu(NO3)3·6H2O, and 49.27 mg of (NH4)6H2W 12 O 40 49.02 mg of Mn(OAc)2·4H2O, 80.60 mg of Fe(NO3)3·9H2O and 1.5 g of PAN were added to 15 mL of DMF and stirred at room temperature for 10 h to obtain a high-entropy precursor solution.

[0043] A2. The high-entropy precursor solution was transferred into a syringe and fixed in an electrospinning device. The anode voltage was set to 15kV, the cathode voltage to 1kV, and the distance between the needle tip and the tin foil collector to 15cm. Electrospinning was carried out continuously for 10h to collect the nanofiber membrane. The membrane was dried at 50℃ for 12h to obtain the nanofiber membrane.

[0044] A3. The nanofiber membrane was graphitized in a chemical vapor deposition furnace: the nanofiber membrane was pre-oxidized by heating at 200°C for 4 hours in an air atmosphere, then switched to an argon atmosphere and heated from 200°C to 800°C at a rate of 2°C / min, held for 5 hours, and then cooled to 600°C at a rate of 2°C / min to obtain rare earth-based high-entropy composite Janus structure nanoparticle catalyst.

[0045] Example 2 like Figure 2 As shown, a rare earth-based high-entropy composite Janus structure nanoparticle catalyst is prepared by the following method: A1. 86.85 mg of Ce(NO3)3·6H2O, 89.22 mg of Eu(NO3)3·6H2O, and 49.27 mg of (NH4)6H2W 12 O 4049.02 mg of Mn(OAc)2·4H2O, 70.61 mg of Co(NO3)2·6H2O and 1.5 g of PAN were added to 15 mL of DMF and stirred at room temperature for 11 h to obtain a high-entropy precursor solution.

[0046] A2. The high-entropy precursor solution was transferred into a syringe and fixed in an electrospinning device. The anode voltage was set to 16kV, the cathode voltage to 2kV, and the distance between the needle tip and the tin foil collector to 18cm. Electrospinning was carried out continuously for 10h to collect the nanofiber membrane. The membrane was dried at 55℃ for 11h to obtain the nanofiber membrane.

[0047] A3. The nanofiber membrane was graphitized in a chemical vapor deposition furnace: the nanofiber membrane was pre-oxidized by heating at 220°C for 3 hours in an air atmosphere, then switched to an argon atmosphere and heated from 220°C to 900°C at a rate of 2°C / min, held for 4 hours, and then cooled to 600°C at a rate of 2°C / min. After cooling and crystallization, a rare earth-based high-entropy composite Janus structure nanoparticle catalyst was obtained.

[0048] Example 3 like Figure 2 As shown, a rare earth-based high-entropy composite Janus structure nanoparticle catalyst is prepared by the following method: A1. 151.99 mg of Ce(NO3)3·6H2O, 66.91 mg of Eu(NO3)3·6H2O, and 49.27 mg of (NH4)6H2W 12 O 40 24.51 mg of Mn(OAc)2·4H2O, 70.61 mg of Co(NO3)2·6H2O and 1.5 g of PAN were added to 15 mL of DMF and stirred at room temperature for 12 h to obtain a high-entropy precursor solution.

[0049] A2. The high-entropy precursor solution was transferred into a syringe and fixed in an electrospinning apparatus. The anode voltage was set to 16kV, the cathode voltage to 1.5kV, and the distance between the needle tip and the tin foil collector to 20cm. Electrospinning was carried out continuously for 10h to collect the nanofiber membrane. The membrane was dried at 60℃ for 10h to obtain the nanofiber membrane.

[0050] A3. The nanofiber membrane was graphitized in a chemical vapor deposition furnace: Under air atmosphere, it was heated to 230℃ for 3 hours for pre-oxidation. Then, the atmosphere was switched to argon, and the temperature was increased from 230℃ to 1000℃ at a rate of 2℃ / min, held for 3 hours, and then decreased to 700℃ at a rate of 2℃ / min. After cooling and crystallization, a rare-earth-based high-entropy composite Janus structure nanoparticle catalyst was obtained. TEM image shown below. Figure 5 As shown.

[0051] Comparative Example 1 A rare earth-based high-entropy composite Janus structure nanoparticle catalyst is prepared in a manner different from that in Example 3, except that Ce(NO3)3·6H2O and Eu(NO3)3·6H2O are not added to Al.

[0052] Comparative Example 2 A rare earth-based high-entropy composite Janus structure nanoparticle catalyst is prepared in a manner different from that in Example 3, graphitization is not performed in A3. Instead, the nanofiber membrane is transferred into a muffle furnace and calcined at 1000°C for 3 hours in an air atmosphere at a rate of 2°C / min.

[0053] Example 4 like Figure 1 As shown, a coal chemical high-salt wastewater treatment process includes: S1. Start the wastewater booster pump and control the influent flow rate to maintain at 80 m³ / h. 3 The wastewater is filtered at a pressure of 0.2 MPa and a pore size of 200 mesh, a frequency of 1500 times / min, and an amplitude of 5 mm. After filtration, the wastewater enters a sedimentation tank.

[0054] S2. Adjust the pH of the wastewater to 6.5, add a 10wt.% polyaluminum chloride aqueous solution (addition amount is 100mg / L wastewater) while stirring at 200rpm, stir for 5min, stir at 50rpm for 10min to promote flocculation, let stand for 60min, and the filtered wastewater enters the oxidation tank.

[0055] S3. Add the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Example 1 (at a rate of 8 g / L wastewater) to the oxidation tank, set the ozone generator flow rate to 0.5 L / min, and use ozone to catalytically oxidize and degrade pollutants. The filtered wastewater then enters the evaporation tank.

[0056] S4. Wastewater undergoes first-effect evaporation at 120℃ and 0.15MPa, followed by second-effect evaporation at 100℃ and 0.08MPa, and finally third-effect evaporation at 85℃ and 0.03MPa. The condensate enters a fixed-bed activated carbon adsorption column at a flow rate of 5 m / h, remains for 15 min, and then enters a UV reactor at a flow rate of 1 m / s. The UV lamp irradiation is set to 20 mJ / cm². 2 Sterilization and filtration produce water that meets discharge standards.

[0057] Example 5 like Figure 1 As shown, a coal chemical high-salt wastewater treatment process includes: S1. Start the wastewater booster pump and control the influent flow rate to maintain 90 m³ / h. 3The wastewater is filtered at a pressure of 0.3 MPa and a pore size of 100 mesh, a frequency of 2000 times / min, and an amplitude of 4 mm. After filtration, the wastewater enters a sedimentation tank.

[0058] S2. Adjust the pH of the wastewater to 7, add a 15wt.% polyaluminum chloride aqueous solution (addition amount is 150mg / L wastewater) while stirring at 250rpm, stir for 3min, then stir slowly at 60rpm for 8min to promote flocculation, let stand for 45min, and the filtered wastewater enters the oxidation tank.

[0059] S3. Add the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Example 2 (at a rate of 9 g / L wastewater) to the oxidation tank, set the ozone generator flow rate to 0.5 L / min, and use ozone to catalytically oxidize and degrade pollutants. The filtered wastewater then enters the evaporation tank.

[0060] S4. Wastewater undergoes first-effect evaporation at 130℃ and 0.2MPa, followed by second-effect evaporation at 110℃ and 0.09MPa, and finally third-effect evaporation at 90℃ and 0.04MPa. The condensate enters a fixed-bed activated carbon adsorption column at a flow rate of 6 m / h, remains for 20 min, and then enters the ultraviolet reactor at a flow rate of 2 m / s. The ultraviolet lamp irradiation is set to 25 mJ / cm². 2 Sterilization and filtration produce water that meets discharge standards.

[0061] Example 6 like Figure 1 As shown, a coal chemical high-salt wastewater treatment process includes: S1. Start the wastewater booster pump and control the influent flow rate to maintain at 100 m³ / h. 3 The wastewater is filtered at a pressure of 0.4 MPa and a pore size of 200 mesh, a frequency of 3000 times / min, and an amplitude of 3 mm. After filtration, the wastewater enters a sedimentation tank.

[0062] S2. Adjust the pH of the wastewater to 7.5, add a 15wt.% polyaluminum chloride aqueous solution (addition amount is 200mg / L wastewater) while stirring at 300rpm, stir for 2min, then stir slowly at 80rpm for 5min to promote flocculation, let stand for 30min, and the filtered wastewater enters the oxidation tank.

[0063] S3. Add the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Example 3 (at a rate of 10 g / L wastewater) to the oxidation tank, set the ozone generator flow rate to 0.5 L / min, and use ozone to catalytically oxidize and degrade pollutants. The filtered wastewater then enters the evaporation tank.

[0064] S4. Wastewater undergoes first-effect evaporation at 130℃ and 0.2MPa, followed by second-effect evaporation at 110℃ and 0.09MPa, and finally third-effect evaporation at 95℃ and 0.05MPa. The condensate enters a fixed-bed activated carbon adsorption column at a flow rate of 8 m / h, remains for 20 min, and then enters a UV reactor at a flow rate of 2 m / s. The UV lamp irradiance is set to 30 mJ / cm². 2 Sterilization and filtration produce water that meets discharge standards.

[0065] Comparative Example 3 A coal chemical high-salt wastewater treatment process, which differs from Example 6 in that the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Comparative Example 1 is used in S3.

[0066] Comparative Example 4 A coal chemical high-salt wastewater treatment process, which differs from Example 6 in that the rare earth-based high-entropy composite Janus structure nanoparticle catalyst prepared in Comparative Example 2 is used in S3.

[0067] The discharge-compliant water samples obtained from Examples 4 to 6, Comparative Examples 3 and 4 were used to analyze COD using a water quality analyzer and measure color using a spectrophotometer.

[0068] Figure 3 The COD removal rates are for samples from Examples 4-6 and Comparative Examples 3 and 4. The COD removal rates in samples from Examples 4-6 are all above 90%, while the COD removal rates in samples from Comparative Examples 3 and 4 are only 20%–40%. Figure 4 The color removal rates are for samples from Examples 4-6 and Comparative Examples 3 and 4. The color removal rates in samples from Examples 4-6 are all above 90%, while the COD removal rates in samples from Comparative Examples 3 and 4 are only 40%–60%.

[0069] This is because, in Comparative Example 3, Ce(NO3)3·6H2O and Eu(NO3)3·6H2O were not added in S1, resulting in insufficient supply of active oxygen species in the prepared catalyst and a sharp reduction in the generation of ·OH, thus poisoning the catalyst and reducing its catalytic activity. In Comparative Example 4, graphitization was not performed in step S3, and the prepared catalyst did not form a Janus structure, making it difficult to cope with complex hydrophilic / hydrophobic pollutants in the wastewater. This led to decreased mass transfer efficiency, increased susceptibility to poisoning and deactivation, and reduced stability. Therefore, the removal rates of COD and color in the treated wastewater were significantly lower than those in Examples 4-6.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process for treating high-salt wastewater from coal chemical industry, characterized in that, include: S1. Turn on the wastewater lift pump and control the inlet flow rate so that the wastewater enters the vibrating screen evenly. After filtration, the wastewater enters the sedimentation tank. S2. Adjust the pH of the wastewater to 6.5~7.5, add coagulant while stirring, stir to promote flocculation, let stand, and filter the wastewater into the oxidation tank. S3. Add a catalyst to the oxidation tank to synergistically degrade pollutants through ozone catalytic oxidation, and the filtered wastewater enters the evaporation tank. S4. Wastewater undergoes multi-effect evaporation and desalination. The condensate is adsorbed by activated carbon and then enters an ultraviolet reactor for ultraviolet sterilization and filtration to obtain compliant discharge water.

2. The coal chemical high-salt wastewater treatment process according to claim 1, characterized in that, In step S1, the influent flow rate is 80~100 m³ / h. 3 The pressure is controlled at 0.2~0.4MPa, the aperture of the vibrating screen is 100~200 mesh, the frequency is controlled at 1500~3000 times / min, and the amplitude is 3~5mm; in step S2, the coagulant is a 10~15wt.% polyaluminum chloride aqueous solution, the amount of coagulant added is 100~200mg / L wastewater, the stirring speed is 200~300rpm, the stirring time is 2~5min, the stirring speed to promote flocculation is 50~80rpm, the time is 5~10min, and the settling time is 30~60min.

3. The coal chemical high-salt wastewater treatment process according to claim 1, characterized in that, In step S3, the catalyst is a rare-earth-based high-entropy composite Janus structure nanoparticle catalyst, and its preparation method includes: A1. Add cerium salt, europium salt, tungsten salt, manganese salt, other metal salts and PAN to DMF, stir to obtain a high-entropy precursor solution, wherein the other metal salts are iron salts or cobalt salts; A2. A high-entropy precursor solution is electrospun and dried to obtain a nanofiber membrane; A3. The nanofiber membrane was placed in a chemical vapor deposition furnace for graphitization: under an air atmosphere, it was heated, then switched to an argon atmosphere, kept warm, and cooled to crystallize, thus obtaining a rare earth-based high-entropy composite Janus structure nanoparticle catalyst.

4. The coal chemical high-salinity wastewater treatment process according to claim 3, characterized in that, In A1, the cerium salt is Ce(NO3)3·6H2O; the europium salt is Eu(NO3)3·6H2O; and the tungsten salt is (NH4)6H2W. 12 O 40 The manganese salt is Mn(OAc)2·4H2O; the iron salt is Fe(NO3)3·9H2O; and the cobalt salt is Co(NO3)2·6H2O.

5. The coal chemical high-salt wastewater treatment process according to claim 4, characterized in that, In A1, the mass-to-volume ratio of cerium salt, europium salt, tungsten salt, manganese salt, Fe(NO3)3·9H2O, PAN, and DMF is (80~180) mg: (60~120) mg: (40~70) mg: (20~60) mg: (60~120) mg: (1.2~1.9) g: 15 mL; the mass-to-volume ratio of cerium salt, europium salt, tungsten salt, manganese salt, Co(NO3)2·6H2O, PAN, and DMF is (80~180) mg: (60~120) mg: (40~70) mg: (20~60) mg: (60~90) mg: (1.2~1.9) g: 15 mL; the stirring time is 10~12 h.

6. The coal chemical high-salt wastewater treatment process according to claim 3, characterized in that, In A2, the electrospinning process parameters are: anode voltage of 15~16kV, cathode voltage of 1~2kV, and needle tip-tin foil collector distance of 15~20cm; the drying temperature is 50~60℃, and the drying time is 10~12h.

7. The coal chemical high-salt wastewater treatment process according to claim 3, characterized in that, In A3, the heating temperature is 200~230℃, and the heating time is 3~4h; the holding temperature is 800~1000℃, and the holding time is 3~5h, with a heating rate of 2℃ / min; the cooling crystallization temperature is 600~700℃, and the cooling rate is 2℃ / min.

8. The coal chemical high-salt wastewater treatment process according to claim 1, characterized in that, In step S3, the amount of catalyst used is (8~10) g / L wastewater; in step S4, the process and parameters of the multi-effect evaporation desalination include: the heating steam temperature of the first-effect evaporation is 120~130℃, and the operating pressure is 0.15~0.2MPa; the heating steam temperature of the second-effect evaporation is 100~110℃, and the operating pressure is 0.08~0.1MPa; the heating steam temperature of the third-effect evaporation is 85~95℃, and the operating pressure is 0.03~0.05MPa.

9. The coal chemical high-salinity wastewater treatment process according to claim 1, characterized in that, In step S4, the activated carbon adsorption process and parameters include: using a fixed-bed activated carbon adsorption column, and using granular coconut shell activated carbon with a specific surface area ≥1000 m². 2 / g, pore size 2~5nm, wastewater enters the activated carbon adsorption column at a flow rate of 5~8m / h, and residence time is 15~20min.

10. The coal chemical high-salt wastewater treatment process according to claim 1, characterized in that, In step S4, the parameters of the ultraviolet reactor are as follows: the wavelength of the ultraviolet lamp used is 254 nm, and the irradiance is 20~30 mJ / cm². 2 The flow rate of wastewater in the ultraviolet reactor is 1~2m / s.

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