A method for preparing a coal coking industrial wastewater purifier based on modified zeolite

Abstract

The present invention discloses a method for preparing a coal coking industrial wastewater purifier based on modified zeolite, comprising the following steps: S1, pre-treating natural zeolite; S2, modifying Fe3O4-CeO2 composite particles; S3, grafting photocatalytic particles to obtain composite modified zeolite; S4, mixing the composite modified zeolite with polyferric sulfate and polyaluminium chloride to obtain a water purifier. The present invention realizes the functional modification of zeolite by grafting Fe3O4-CeO2 composite particles and photocatalytic particles on zeolite, and the obtained composite modified zeolite not only has significantly improved physical adsorption capacity, but also has the performance of photocatalytic oxidation degradation of organic matter, thereby greatly improving its water treatment effect. Finally, a water purifier suitable for deep treatment of coal coking industrial wastewater is prepared by compounding composite modified zeolite with polyferric sulfate and polyaluminium chloride.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, and in particular to a method for preparing a coal coking industry wastewater purifier based on modified zeolite. Background Art

[0002] Coking wastewater is high CODcr, high ammonia nitrogen, and high phenol industrial wastewater produced in the processes of coking, coal gas purification, and coking product recovery. It is highly toxic and needs to be treated before it can be discharged.

[0003] The biochemical method is a commonly used method for treating coking wastewater. It can effectively reduce phenols and cyanides in the wastewater, but the removal rate of difficult-to-degrade organic matter and ammonia nitrogen is relatively low. Therefore, further deep treatment is usually carried out after biochemical treatment, such as adding water purifiers with adsorption, flocculation and / or oxidation functions for re-purification.

[0004] Patent CN111646534A discloses a coking phenol-cyanide wastewater purifier and its preparation method and application. The purifier is prepared by compounding attapulgite, bentonite, fly ash, zeolite powder, silane coupling agent, dimethyldiallylammonium chloride, potassium persulfate, sodium carboxymethyl cellulose, polyferric sulfate, polyaluminum ferric silicate, ferrous sulfate, magnesium sulfate heptahydrate, trisodium phosphate, polyacrylamide, polyvinyl pyrrolidone and calcium hydroxide as raw materials to perform deep treatment of biochemical effluent in the coking wastewater treatment process, achieving good results, but its composition is complex.

[0005] Patent CN110577254A discloses a water purifier for use in coal chemical industry, coking and other chemical industries and its preparation method. The water purifier is prepared from carboxymethyl cellulose, modified chitosan, phenolic acid, composite aluminum iron, xanthan gum, cationic guar gum, acid solution, potassium aluminum sulfate dodecahydrate, polyacrylamide, polymerized ferric sulfate, ST and other raw materials for deep treatment of biochemical effluent in coking wastewater treatment process, but the COD removal effect is poor.

[0006] Zeolite is a renewable mineral with rich pore structure, acid and alkali resistance, corrosion resistance, strong stability and low cost. It is widely used in water treatment as an adsorption material, such as the zeolite-porous carbon-photocatalyst ternary composite material disclosed in patent CN110302828A, its preparation method and wastewater treatment device, and a zeolite-activated carbon composite filter cascade biofilter water treatment system and treatment process disclosed in patent CN106186579A. However, natural zeolite mainly removes pollutants through physical adsorption, and has the defect of limited adsorption capacity for ammonia nitrogen and organic pollutants.

[0007] Therefore, it is necessary to improve the existing technology to provide a more reliable solution. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for preparing a coal coking industrial wastewater purifier based on modified zeolite in view of the deficiencies in the above-mentioned prior art.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a coal coking industrial wastewater purifier based on modified zeolite, comprising the following steps:

[0010] S1. Pretreating natural zeolite;

[0011] S2, modifying Fe3O4-CeO2 composite particles on the pretreated zeolite;

[0012] S3, grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots;

[0013] S4, mixing the composite modified zeolite with polyferric sulfate and polyaluminium chloride to obtain the water purifier.

[0014] Preferably, the step S1 specifically includes:

[0015] S1-1, crush the natural zeolite, then add it into distilled water, soak for 0.5-2h, filter and dry;

[0016] S1-2, calcining at 200-300°C for 1-6h, and cooling naturally;

[0017] S1-3, add to sodium hydroxide solution and soak for 1-4 hours, filter, and wash with deionized water;

[0018] S1-4, adding to sodium chloride solution and soaking for 0.5-2h, filtering, washing with deionized water, and drying to obtain the pretreated zeolite.

[0019] Preferably, the step S1 specifically includes:

[0020] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0021] S1-2, calcining at 250°C for 3h and cooling naturally;

[0022] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0023] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0024] Preferably, the step S2 specifically includes:

[0025] S2-1, adding the pretreated zeolite into ethanol and soaking it for 5-20 minutes, filtering it, and then adding it into deionized water, and ultrasonicating it for 10-30 minutes to obtain a zeolite dispersion;

[0026] S2-2, dissolving 0.01-0.05 mol Fe(NO3)3·9H2O and 0.005-0.03 mol Ce(NO3)3·6H2O in 150 mL of deionized water, adding the obtained solution to the zeolite dispersion and stirring for 5-30 min, then adding 20-100 mL of 1.0 M NaOH solution under stirring to obtain a mixture;

[0027] S2-3. The mixture is transferred to a reactor, reacted at 160-240°C for 4-12 hours, dried after the reaction, and then calcined at 400-600°C in a nitrogen atmosphere for 2-6 hours to obtain a zeolite modified with Fe3O4-CeO2 composite particles.

[0028] Preferably, the step S2 specifically includes:

[0029] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0030] S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0031] S2-3. The mixture was transferred to a reactor and reacted at 220°C for 6 hours. After the reaction, it was dried and then calcined at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles.

[0032] Preferably, in step S2-2, the raw materials are added in a mass ratio of Fe:zeolite of 3:2.

[0033] Preferably, the step S3 specifically includes:

[0034] S3-1. Preparation of photocatalytic particles:

[0035] S3-1-1, adding folic acid, thiourea and ethylenediamine into deionized water, and ultrasonicating for 2-10 minutes to obtain a precursor solution;

[0036] S3-1-2, adding the precursor solution into the reaction kettle of the polytetrafluoroethylene substrate, and reacting at 160-230°C for 3-12h;

[0037] S3-1-3, after the reaction is completed, the mixture is cooled naturally and filtered with a filter membrane. The filtrate is dialyzed in deionized water for 6-24 hours using a dialysis bag with a molecular weight cutoff of 600-1200D, the dialysate in the dialysis bag is collected, and freeze-dried to obtain the S and N-doped carbon dots, i.e., the photocatalytic particles;

[0038] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0039] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 10-30 minutes to prepare a photocatalytic particle dispersion;

[0040] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 1-4 hours, filtering, and drying;

[0041] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 55-95°C for 6-24h, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0042] Preferably, the step S3 specifically includes:

[0043] S3-1. Preparation of photocatalytic particles:

[0044] S3-1-1, add 6.2 g of folic acid, 4.7 g of thiourea, and 2.5 g of ethylenediamine into 180 mL of deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0045] S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0046] S3-1-3, after the reaction is completed, the mixture is cooled naturally, filtered with a 0.25 μm filter membrane, and the filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800D, the dialysate in the dialysis bag is collected, and freeze-dried to obtain the S and N-doped carbon dots, i.e., the photocatalytic particles;

[0047] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0048] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0049] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0050] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0051] Preferably, in the step S3-2-2, the raw materials are added in a mass ratio of zeolite for modifying the Fe3O4-CeO2 composite particles to photocatalytic particles of 10:1-10:3.5.

[0052] Preferably, the step S4 is specifically as follows: mixing the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heating at 95°C for 2h, and then grinding to a mass ratio of more than 95% below 200 mesh to obtain the water purifier.

[0053] The beneficial effects of the present invention are:

[0054] The present invention provides a method for preparing a water purifier for coal coking industrial wastewater based on modified zeolite. Firstly, the zeolite is subjected to roasting, alkali leaching and salt leaching treatment, so as to effectively increase the pore volume and specific surface area of ​​the zeolite and improve its physical adsorption capacity. Then, the zeolite is functionally modified by grafting Fe3O4-CeO2 composite particles and photocatalytic particles. The obtained composite modified zeolite not only has significantly improved physical adsorption capacity, but also has the performance of photocatalytic oxidation and degradation of organic matter, so as to greatly improve its water treatment effect. Finally, a water purifier suitable for deep treatment of coal coking industrial wastewater is prepared by compounding the composite modified zeolite with polyferric sulfate and polyaluminium chloride.

[0055] In the present invention, a S, N doped carbon dot with photocatalytic oxidation ability is prepared and grafted onto a zeolite modified with Fe3O4-CeO2 composite particles, so that the zeolite has the ability to photocatalytically oxidize and degrade organic matter, and the Fe3O4-CeO2 composite particles have a promoting effect on this oxidation ability, and ultimately the degradation efficiency of organic matter can be improved;

[0056] In the present invention, Fe3O4-CeO2 composite particles are formed by in-situ grafting on the surface of zeolite, which have a certain adsorption effect on organic matter on the one hand, and promote photocatalysis on the other hand; and Fe3O4 is magnetic, so that the water purifier can be easily recycled and reused when a magnetic field is applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a scanning electron microscope image of the carbon dots prepared in Example 3;

[0058] Figure 2 This is a scanning electron microscope image of the composite modified zeolite prepared in Example 3. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0060] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0061] The test methods used in the following examples are conventional methods unless otherwise specified. The materials and reagents used in the following examples are all commercially available unless otherwise specified. In the following examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not specified, are all conventional products that can be purchased commercially.

[0062] The present invention provides a method for preparing a coal coking industrial wastewater purifier based on modified zeolite, comprising the following steps:

[0063] S1. Pretreatment of natural zeolite:

[0064] S1-1, crush the natural zeolite, then add it into distilled water, soak for 0.5-2h, filter and dry;

[0065] S1-2, calcining at 200-300°C for 1-6h, and cooling naturally;

[0066] S1-3, add to sodium hydroxide solution and soak for 1-4 hours, filter, and wash with deionized water;

[0067] S1-4, adding to sodium chloride solution and soaking for 0.5-2h, filtering, washing with deionized water, and drying to obtain the pretreated zeolite.

[0068] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0069] S2-1, adding the pretreated zeolite into ethanol and soaking it for 5-20 minutes, filtering it, and then adding it into deionized water, and ultrasonicating it for 10-30 minutes to obtain a zeolite dispersion;

[0070] S2-2, dissolving 0.01-0.05 mol Fe(NO3)3·9H2O and 0.005-0.03 mol Ce(NO3)3·6H2O in 150 mL of deionized water, adding the obtained solution to the zeolite dispersion and stirring for 5-30 min, then adding 20-100 mL of 1.0 M NaOH solution under stirring to obtain a mixture;

[0071] S2-3. The mixture is transferred to a reactor, reacted at 160-240°C for 4-12 hours, dried after the reaction, and then calcined at 400-600°C in a nitrogen atmosphere for 2-6 hours to obtain a zeolite modified with Fe3O4-CeO2 composite particles.

[0072] S3. Grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots:

[0073] S3-1. Preparation of photocatalytic particles:

[0074] S3-1-1, adding folic acid, thiourea and ethylenediamine into deionized water, and ultrasonicating for 2-10 minutes to obtain a precursor solution;

[0075] S3-1-2, adding the precursor solution into the reaction kettle of the polytetrafluoroethylene substrate, and reacting at 160-230°C for 3-12h;

[0076] S3-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a filter membrane. The filtrate is dialyzed in deionized water for 6-24 hours using a dialysis bag with a molecular weight cutoff of 600-1200D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0077] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0078] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 10-30 minutes to prepare a photocatalytic particle dispersion;

[0079] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 1-4 hours, filtering, and drying;

[0080] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 55-95°C for 6-24h, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0081] S4. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 75-120° C. for 1-4 h, and then grind to a mass ratio of more than 95% below 200-300 mesh to obtain a water purifier.

[0082] The water purifier of the present invention has the performance of photocatalytic oxidation degradation of organic matter, and when treating coal coking industrial wastewater, better effect can be obtained by cooperating with illumination and aeration processes.

[0083] Zeolite is a renewable mineral with rich pore structure, acid and alkali resistance and corrosion resistance. It has strong stability and low cost. It is widely used in the field of water treatment as an adsorption material. However, natural zeolite mainly removes pollutants by physical adsorption, and has the defect of limited adsorption capacity for ammonia nitrogen and organic pollutants. In the present invention, firstly, by calcining, alkali leaching and salt leaching the zeolite, the pore volume and specific surface area of ​​the zeolite can be effectively increased, and its physical adsorption capacity can be improved; then, by grafting Fe3O4-CeO2 composite particles and photocatalytic particles, the functional modification of the zeolite is realized, and the obtained composite modified zeolite not only has significantly improved physical adsorption capacity, but also has the performance of photocatalytic oxidation and degradation of organic matter, thereby greatly improving its water treatment effect. Finally, a water purifier suitable for deep treatment of coal coking industrial wastewater is prepared by compounding the composite modified zeolite with polyferric sulfate and polyaluminum chloride. The principle is described in detail below.

[0084] In the present invention, firstly, the bound water inside the pores of natural zeolite can be removed by calcination to increase the pore volume; the micropores can be further enlarged by alkali leaching, and the divalent cations (Ca2+) with larger particle size in attapulgite can be replaced by sodium ions with smaller particle size through salt leaching. 2+ Mg 2+ On the one hand, it can increase the pore volume, and on the other hand, it can improve the electronegativity of the material, thereby being more conducive to improving the adsorption and removal effect of cations such as ammonia nitrogen;

[0085] In the present invention, Fe3O4-CeO2 composite particles are formed by in-situ grafting on the surface of zeolite, which have a certain adsorption effect on organic matter on the one hand, and promote photocatalysis on the other hand; in the process of forming the Fe3O4-CeO2 composite particles, iron ions and cerium ions can be evenly connected to the surface of the zeolite through coordination with hydroxyl groups on the surface of the zeolite and / or electrostatic adsorption, and then calcined to form the Fe3O4-CeO2 composite particles in situ;

[0086] In the present invention, a S and N doped carbon dot with photocatalytic oxidation ability is prepared and grafted onto a zeolite modified with Fe3O4-CeO2 composite particles, so that the zeolite has the ability to photocatalytically oxidize and degrade organic matter, and the Fe3O4-CeO2 composite particles have a promoting effect on this oxidation ability. The main working principle is that the carbon dot absorbs long-wavelength visible light and is excited to a high-energy state, and emits short-wavelength ultraviolet photons, and O2 or other oxygen-containing oxidants obtain the conduction band electrons of the carbon dot and its semiconductor heterojunction to form superoxide radicals (·O 2- ) and hydroxyl radicals (·OH), which can attack organic matter and degrade it; in this process, Ce can promote the photoinduced charge transfer process of carbon dots, enhance the light absorption capacity of carbon dots, and thus enhance the photooxidation activity of carbon dots, and ultimately improve the degradation efficiency of organic matter; at the same time, Fe3O4, as a widely used Fenton-like catalyst, can also promote the oxidation photoprocess, and can further increase the generation of strong oxidizing active radicals, and Fe3O4 has magnetism, so that the water purifier can be easily recovered when a magnetic field is applied, and can be reused after being treated with a regeneration agent (such as sodium hydroxide, etc.);

[0087] During the modification process of carbon dots, on the one hand, the abundant carboxyl groups on the surface of carbon dots react with the hydroxyl groups on the surface of zeolite to achieve bonding. On the other hand, the coordination effect between the oxygen-containing functional groups on the surface of carbon dots and Ce can also promote the uniform and firm bonding of carbon dots on the surface of zeolite.

[0088] In the present invention, folic acid, thiourea and ethylenediamine are used as main raw materials to synthesize a kind of S and N doped carbon dots by hydrothermal method. The surface of the carbon dots has abundant functional groups such as carboxyl and amino groups. Such functional groups can adsorb and remove some heavy metal ion pollutants in water. The doping of S and N can increase the visible light absorption range of the carbon dots and improve the photocatalytic efficiency.

[0089] Example 1

[0090] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0091] S1. Pretreatment of natural zeolite:

[0092] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0093] S1-2, calcining at 250°C for 3h and cooling naturally;

[0094] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0095] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0096] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0097] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0098] S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0099] The raw materials were added at a mass ratio of Fe:zeolite of 3:2;

[0100] S2-3, transferring the mixture to a reactor, reacting at 220°C for 6 hours, drying after the reaction, and then calcining at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles;

[0101] S3. Grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots:

[0102] S3-1. Preparation of photocatalytic particles:

[0103] S3-1-1, add 6.2 g of folic acid, 4.7 g of thiourea, and 2.5 g of ethylenediamine into 180 mL of deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0104] S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0105] S3-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a 0.25 μm filter membrane. The filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800 D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0106] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0107] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0108] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0109] The raw materials are added in a mass ratio of zeolite to photocatalytic particles of modified Fe3O4-CeO2 composite particles of 10:2;

[0110] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0111] S4. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95° C. for 2 h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0112] Example 2

[0113] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0114] S1. Pretreatment of natural zeolite:

[0115] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0116] S1-2, calcining at 250°C for 3h and cooling naturally;

[0117] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0118] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0119] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0120] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0121] S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0122] The raw materials were added at a mass ratio of Fe:zeolite of 1:1;

[0123] S2-3, transferring the mixture to a reactor, reacting at 220°C for 6 hours, drying after the reaction, and then calcining at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles;

[0124] S3. Grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots:

[0125] S3-1. Preparation of photocatalytic particles:

[0126] S3-1-1, add 6.2 g folic acid, 4.7 g thiourea and 2.5 g ethylenediamine into 180 mL deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0127] S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0128] S3-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a 0.25 μm filter membrane. The filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800 D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0129] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0130] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0131] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0132] The raw materials are added in a mass ratio of zeolite to photocatalytic particles of modified Fe3O4-CeO2 composite particles of 10:2;

[0133] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0134] S4. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95° C. for 2 h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0135] Example 3

[0136] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0137] S1. Pretreatment of natural zeolite:

[0138] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0139] S1-2, calcining at 250°C for 3h and cooling naturally;

[0140] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0141] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0142] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0143] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0144] S2-2, 0.02 mol Fe(NO3)3.·9H2O and 0.015 mol Ce(NO3)3.·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0145] The raw materials were added at a mass ratio of Fe:zeolite of 3:2;

[0146] S2-3, transferring the mixture to a reactor, reacting at 220°C for 6 hours, drying after the reaction, and then calcining at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles;

[0147] S3. Grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots:

[0148] S3-1. Preparation of photocatalytic particles:

[0149] S3-1-1, add 6.2 g folic acid, 4.7 g thiourea and 2.5 g ethylenediamine into 180 mL deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0150] S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0151] S3-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a 0.25 μm filter membrane. The filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800 D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0152] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0153] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0154] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0155] The raw materials are added in a mass ratio of zeolite to photocatalytic particles of modified Fe3O4-CeO2 composite particles of 10:3;

[0156] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0157] S4. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95° C. for 2 h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0158] Example 4

[0159] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0160] S1. Pretreatment of natural zeolite:

[0161] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0162] S1-2, calcining at 250°C for 3h and cooling naturally;

[0163] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0164] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0165] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0166] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0167] S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0168] The raw materials were added at a mass ratio of Fe:zeolite of 3:2;

[0169] S2-3, transferring the mixture to a reactor, reacting at 220°C for 6 hours, drying after the reaction, and then calcining at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles;

[0170] S3. Grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots:

[0171] S3-1. Preparation of photocatalytic particles:

[0172] S3-1-1, add 6.2 g folic acid, 4.7 g thiourea and 2.5 g ethylenediamine into 180 mL deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0173] S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0174] S3-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a 0.25 μm filter membrane. The filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800 D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0175] S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles:

[0176] S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0177] S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0178] The raw materials are added according to the mass ratio of zeolite for modifying Fe3O4-CeO2 composite particles to photocatalytic particles of 10:3.5;

[0179] S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0180] S4. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95° C. for 2 h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0181] Comparative Example 1

[0182] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0183] S1. Pretreatment of natural zeolite:

[0184] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0185] S1-2, calcining at 250°C for 3h and cooling naturally;

[0186] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0187] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0188] S2. The pretreated zeolite is mixed with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heated at 95° C. for 2 h, and then ground to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0189] Comparative Example 2

[0190] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0191] S1. Pretreatment of natural zeolite:

[0192] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0193] S1-2, calcining at 250°C for 3h and cooling naturally;

[0194] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0195] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0196] S2. Modifying Fe3O4-CeO2 composite particles on the pretreated zeolite:

[0197] S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion;

[0198] S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture;

[0199] The raw materials were added at a mass ratio of Fe:zeolite of 3:2;

[0200] S2-3, transferring the mixture to a reactor, reacting at 220°C for 6 hours, drying after the reaction, and then calcining at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles;

[0201] S3. Mix the zeolite modified with Fe3O4-CeO2 composite particles with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95°C for 2h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0202] Comparative Example 3

[0203] A method for preparing a coal coking industrial wastewater purifier based on modified zeolite comprises the following steps:

[0204] S1. Pretreatment of natural zeolite:

[0205] S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry;

[0206] S1-2, calcining at 250°C for 3h and cooling naturally;

[0207] S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water;

[0208] S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

[0209] S2. Grafting photocatalytic particles onto the pretreated zeolite to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N-doped carbon dots:

[0210] S2-1. Preparation of photocatalytic particles:

[0211] S2-1-1, add 6.2 g of folic acid, 4.7 g of thiourea, and 2.5 g of ethylenediamine into 180 mL of deionized water, and ultrasonicate for 5 min to obtain a precursor solution;

[0212] S2-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours;

[0213] S2-1-3. After the reaction is completed, the mixture is cooled naturally and filtered with a 0.25 μm filter membrane. The filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800 D. The dialysate in the dialysis bag is collected and freeze-dried to obtain S and N-doped carbon dots, i.e., photocatalytic particles.

[0214] S2-2, grafting photocatalytic particles onto the pretreated zeolite:

[0215] S2-2-1, adding the photocatalytic particles prepared in step S2-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL;

[0216] S2-2-2, adding the pretreated zeolite prepared in step S1 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying;

[0217] The raw materials were added in a mass ratio of 10:3 of the pretreated zeolite to the photocatalytic particles;

[0218] S2-2-3. Add the pretreated zeolite obtained in step S2-2-2 to the photocatalytic particle dispersion obtained in step S2-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

[0219] S3. Mix the composite modified zeolite with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heat at 95° C. for 2 h, and then grind to a mass ratio of more than 95% below 200 mesh to obtain a water purifier.

[0220] Reference Figure 1 , is a scanning electron microscope image of the carbon dots prepared in Example 3, Figure 2 This is a scanning electron microscope image of the composite modified zeolite prepared in Example 3.

[0221] The following uses the biochemical effluent from the wastewater treatment process of a coking plant in Shanxi as wastewater to test the water purifiers prepared in the above examples and comparative examples. The main pollutant indicators of the wastewater are shown in Table 1 below:

[0222] Table 1

[0223] Ammonia nitrogen (mg / L) CODcr(mg / L) Chroma(times) Biochemical effluent 339.6 57.8 204

[0224] The test method is: add 0.2g of water purifier to 1L of biochemical effluent, aerate and stir for 1h, then let it stand for 0.5h, take the supernatant to detect the ammonia nitrogen concentration, CODcr concentration and chromaticity, calculate the ammonia nitrogen removal rate, CODcr removal rate and chromaticity removal rate, and the measurement results are shown in Table 2 below:

[0225] Table 2

[0226] Ammonia nitrogen removal rate (%) CODcr removal rate (%) Chroma removal rate (%) Example 1 87.3 92.7 94.9 Example 2 88.6 93.1 95.2 Example 3 90.7 95.2 96.4 Example 4 91.2 95.8 97.1 Comparative Example 1 49.7 63.2 75.5 Comparative Example 2 72.9 78.4 80.1 Comparative Example 3 82.4 87.6 90.3

[0227] From the above results, it can be seen that the methods of Examples 1-4 for preparing water purifiers have good removal effects on ammonia nitrogen, organic matter and chromaticity in wastewater. The zeolite in Comparative Example 1 has not been functionally modified and only has a physical adsorption effect, and the removal effect on ammonia nitrogen and organic matter is poor. The zeolite in Comparative Example 2 has not been modified with photocatalytic particles having photocatalytic oxidation activity, resulting in poor degradation and removal effect on organic matter. In Comparative Example 3, since the Fe3O4-CeO2 composite particles are not modified, the degradation and removal effect of the water purifier on organic matter is significantly reduced.

[0228] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for preparing a coal coking industrial wastewater purifier based on modified zeolite, characterized in that: The following steps are involved: S1. Pretreating natural zeolite; S2, modifying Fe3O4-CeO2 composite particles on the pretreated zeolite; S3, grafting photocatalytic particles onto the zeolite modified with Fe3O4-CeO2 composite particles to obtain a composite modified zeolite, wherein the photocatalytic particles are S and N doped carbon dots; S4, mixing the composite modified zeolite with polyferric sulfate and polyaluminium chloride to obtain the water purifier; The step S1 specifically includes: S1-1, crush the natural zeolite, then add it into distilled water, soak for 0.5-2h, filter and dry; S1-2, calcining at 200-300°C for 1-6h, and cooling naturally; S1-3, add to sodium hydroxide solution and soak for 1-4 hours, filter, and wash with deionized water; S1-4, adding to a sodium chloride solution and soaking for 0.5-2h, filtering, washing with deionized water, and drying to obtain a pretreated zeolite; The step S2 specifically includes: S2-1, adding the pretreated zeolite into ethanol and soaking it for 5-20 minutes, filtering it, and then adding it into deionized water, and ultrasonicating it for 10-30 minutes to obtain a zeolite dispersion; S2-2, dissolving 0.01-0.05 mol Fe(NO3)3·9H2O and 0.005-0.03 mol Ce(NO3)3·6H2O in 150 mL of deionized water, adding the obtained solution to the zeolite dispersion and stirring for 5-30 min, then adding 20-100 mL of 1.0 M NaOH solution under stirring to obtain a mixture; S2-3, transferring the mixture to a reactor, reacting at 160-240°C for 4-12h, drying after the reaction, and then calcining at 400-600°C in a nitrogen atmosphere for 2-6h to obtain a zeolite modified with Fe3O4-CeO2 composite particles; The step S3 specifically includes: S3-1. Preparation of photocatalytic particles: S3-1-1, adding folic acid, thiourea and ethylenediamine into deionized water, and ultrasonicating for 2-10 minutes to obtain a precursor solution; S3-1-2, adding the precursor solution into the reaction kettle of the polytetrafluoroethylene substrate, and reacting at 160-230°C for 3-12h; S3-1-3, after the reaction is completed, the mixture is cooled naturally and filtered with a filter membrane. The filtrate is dialyzed in deionized water for 6-24 hours using a dialysis bag with a molecular weight cutoff of 600-1200D, the dialysate in the dialysis bag is collected, and freeze-dried to obtain the S and N-doped carbon dots, i.e., the photocatalytic particles; S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles: S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 10-30 minutes to prepare a photocatalytic particle dispersion; S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 1-4 hours, filtering, and drying; S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 55-95°C for 6-24h, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

2. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 1, characterized in that: The step S1 specifically includes: S1-1, crush the natural zeolite to a mass fraction of more than 95% below 200 mesh, then add it into distilled water, soak for 1 hour, filter and dry; S1-2, calcining at 250°C for 3h and cooling naturally; S1-3, add to 0.5 mol / L sodium hydroxide solution and soak for 2 hours, filter, and wash with deionized water; S1-4, adding it to a 0.5 mol / L sodium chloride solution and soaking it for 1 hour, filtering it, washing it with deionized water, and drying it to obtain the pretreated zeolite.

3. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 1, characterized in that: The step S2 specifically includes: S2-1, adding the pretreated zeolite into ethanol and soaking it for 10 minutes, filtering it, and then adding it into deionized water and ultrasonicating it for 20 minutes to obtain a zeolite dispersion; S2-2, 0.02 mol Fe(NO3)3·9H2O and 0.015 mol Ce(NO3)3·6H2O were dissolved in 150 mL of deionized water, the obtained solution was added to the zeolite dispersion and stirred for 15 min, and then 50 mL of 1.0 M NaOH solution was added under stirring to obtain a mixture; S2-3. The mixture was transferred to a reactor and reacted at 220°C for 6 hours. After the reaction, it was dried and then calcined at 480°C for 4 hours in a nitrogen atmosphere to obtain a zeolite modified with Fe3O4-CeO2 composite particles.

4. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 3, characterized in that: In the step S2-2, raw materials are added in a mass ratio of Fe:zeolite of 3:

2.

5. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 1, characterized in that: The step S3 specifically includes: S3-1. Preparation of photocatalytic particles: S3-1-1, add 6.2 g of folic acid, 4.7 g of thiourea, and 2.5 g of ethylenediamine into 180 mL of deionized water, and ultrasonicate for 5 min to obtain a precursor solution; S3-1-2, add the precursor solution into a 200 mL polytetrafluoroethylene-lined reactor and react at 190°C for 6 hours; S3-1-3, after the reaction is completed, the mixture is cooled naturally, filtered with a 0.25 μm filter membrane, and the filtrate is dialyzed in deionized water for 12 h using a dialysis bag with a molecular weight cutoff of 800D, the dialysate in the dialysis bag is collected, and freeze-dried to obtain the S and N-doped carbon dots, i.e., the photocatalytic particles; S3-2, grafting photocatalytic particles onto zeolite modified with Fe3O4-CeO2 composite particles: S3-2-1, adding the photocatalytic particles prepared in step S3-1 into deionized water, and ultrasonicating for 20 minutes to prepare a photocatalytic particle dispersion with a concentration of 2 mg / mL; S3-2-2, adding the zeolite modified Fe3O4-CeO2 composite particles prepared in step S2 into an ethanol aqueous solution, soaking for 2 hours, filtering, and drying; S3-2-3. Add the zeolite modified with Fe3O4-CeO2 composite particles obtained in step S3-2-2 to the photocatalytic particle dispersion obtained in step S3-2-1, and add EDCI, shake at 75°C for 12 hours, filter, wash with ethanol and deionized water in turn, and dry to obtain a composite modified zeolite.

6. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 5, characterized in that: In the step S3-2-2, raw materials are added according to a mass ratio of zeolite for modifying Fe3O4-CeO2 composite particles to photocatalytic particles of 10:1-10:3.

5.

7. The method for preparing a coal coking industrial wastewater purifier based on modified zeolite according to claim 1, characterized in that: The step S4 is specifically as follows: the composite modified zeolite is mixed with polyferric sulfate and polyaluminium chloride in a mass ratio of composite modified zeolite: polyferric sulfate: polyaluminium chloride = 1:0.8:0.5, heated at 95°C for 2h, and then ground to a mass ratio of more than 95% below 200 mesh, to obtain the water purifier.

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