Method for preparing sulfur self-supporting filter material based on rubber tire waste and prepared sulfur self-supporting filter material

Abstract

The present application relates to the field of water treatment, and specifically discloses a method for preparing a sulfur autotrophic filter material based on rubber tire waste and the prepared sulfur autotrophic filter material, comprising the following steps: S1, crushing and screening waste rubber tires to obtain rubber particle waste; S2, alkali-washing and then acid-washing the rubber waste to obtain activated rubber; S3, loading a sulfur autotrophic agent containing a sulfur source on the activated rubber, and drying to obtain composite rubber particles; S4, mixing the composite rubber particles with a binder and pressing them to form filter material balls; S5, inoculating sulfur-oxidizing bacteria on the filter material balls and then activating them to obtain the sulfur autotrophic filter material. The present application also discloses the sulfur autotrophic filter material prepared by the above method. The present application has the characteristics of using rubber tire waste to prepare water treatment filter material with sulfur autotrophic function, solving the environmental pollution problem of waste tires, and reducing the cost of the sulfur autotrophic filter material.

Description

Technical Field

[0001] The present application relates to the field of water treatment, and more specifically, to a method for preparing a sulfur autotrophic filter material based on rubber tire waste and the prepared sulfur autotrophic filter material. Background Art

[0002] With the rapid development of the global automotive industry, the amount of waste rubber tires is increasing year by year. Properly disposing of these waste tires has become a serious environmental challenge. Traditional disposal methods primarily include landfill and incineration, but these methods not only consume significant land resources and energy but also easily cause secondary pollution, such as soil and air contamination. Therefore, finding an efficient and environmentally friendly method for recycling waste tires is crucial.

[0003] At the same time, with the acceleration of industrialization, water pollution is becoming increasingly serious, especially the discharge of sulfur-containing wastewater, which has caused significant damage to the environment. In the field of water treatment, filter media is one of the key materials for removing water pollutants, and its performance directly affects the effectiveness of water purification. However, most filter media currently on the market suffer from high costs and low efficiency when treating sulfur-containing wastewater, making it difficult to meet the needs of practical applications.

[0004] In recent years, sulfur autotrophic filter media has received widespread attention as an emerging functional material. Sulfur autotrophic filter media can use sulfide as an electron donor and oxidize sulfide into sulfate under the action of microorganisms, thereby effectively removing pollutants in water. However, the current cost of sulfur autotrophic filter media is relatively high, which limits its large-scale application. Applying rubber tire waste to water treatment filter media with sulfur autotrophic function can not only solve the environmental pollution problem of waste tires, but also provide new solutions for the water treatment industry. Summary of the Invention

[0005] In order to use rubber tire waste to prepare water treatment filter material with sulfur autotrophic function, solve the environmental pollution problem of waste tires, and reduce the cost of sulfur autotrophic filter material, the present application provides a method for preparing sulfur autotrophic filter material based on rubber tire waste and the prepared sulfur autotrophic filter material.

[0006] In a first aspect, the present application provides a method for preparing sulfur autotrophic filter material based on rubber tire waste, using the following technical solution:

[0007] A method for preparing sulfur autotrophic filter material based on rubber tire waste comprises the following steps:

[0008] S1, crushing and screening waste rubber tires to obtain rubber particle waste;

[0009] S2, alkali washing and then acid washing the rubber waste to obtain activated rubber;

[0010] S3, loading a sulfur autotrophic agent containing a sulfur source on the activated rubber, and drying to obtain composite rubber particles;

[0011] S4, mixing the composite rubber particles with the binder and pressing them to form filter balls;

[0012] S5. Sulfur-oxidizing bacteria are inoculated onto the filter balls and activated to produce sulfur-autotrophic filter media.

[0013] By adopting the above technical scheme, in this application, waste rubber tires are used as raw materials, and after crushing, they are alkali-washed to remove surface oil stains, and then acid-washed to treat the surface of the rubber particles to improve the surface roughness and specific surface area, provide binding sites for the sulfur autotrophic agent, and then load the sulfur autotrophic agent. After that, they are bonded and pressed into filter material, and then inoculated with microorganisms for activation to obtain sulfur autotrophic filter material. This not only realizes the resource utilization of waste rubber tires and reduces environmental pollution, but also the treatment of its sulfur autotrophic agent and sulfur oxidizing bacteria, and the filter material obtained has sulfur autotrophic function. When wastewater passes through the sulfur autotrophic filter material, the pollutants in the wastewater are first adsorbed by the filter material, and then the sulfur oxidizing bacteria use the sulfur autotrophic agent as energy to convert the pollutants into harmless substances, remove sulfide and nitrogen in the wastewater, efficiently treat sulfur-containing wastewater, and reduce water treatment costs. Moreover, the addition of the binder forms a three-dimensional network structure during the pressing process, which enhances the mechanical strength. The obtained filter material has good mechanical strength and chemical stability, is suitable for a variety of water treatment scenarios, and has a simple preparation process and is easy to mass produce.

[0014] In addition, rubber tire waste is selected as the carrier in this application. On the one hand, the elasticity of rubber is utilized to make the filter material more stable during backwashing and not easy to break. At the same time, it avoids the shedding of biofilm and maintains long-term pore stability, thereby improving the service life and long-term use effect of the filter material.

[0015] Optionally, the specific operation of alkali washing in step S2 is to wash the rubber waste in a 5-10wt% sodium hydroxide solution, and then soak the rubber waste in a 10-20wt% sulfuric acid solution for 20-40 minutes to obtain activated rubber.

[0016] By adopting the above technical solution, sodium hydroxide is first used to remove grease, impurities, etc. on the surface of the rubber waste, and some amorphous rubber chains are corroded to form a rough surface. Then, the rubber waste is immersed in a sulfuric acid solution, and oxygen-containing functional groups such as carboxyl and hydroxyl groups are introduced through sulfuric acid to enhance the chemical reaction activity and hydrophilicity of the rubber waste surface, thereby providing binding sites for the sulfur autotrophic agent.

[0017] Optionally, the sulfur autotrophic agent in step S3 includes a sulfur source and a nutrient in a mass ratio of 1:(0.8-1.2), the sulfur source includes one or more of elemental sulfur and sulfides such as sodium sulfide or sodium thiosulfate, and the nutrient is one or more of phosphate and nitrogen source.

[0018] By adopting the above technical solution, the sulfur source in the present application provides the necessary energy as sulfur autotrophic bacteria, so that the sulfur autotrophic bacteria use the sulfur source as an electron donor and reduce nitrate nitrogen in the water into nitrogen gas through reactions such as autotrophic denitrification, thereby realizing wastewater nitrogen removal. At the same time, in this process, the sulfur autotrophic bacteria form a biofilm on the surface of the filter material, which has an adsorption and degradation effect on pollutants such as sulfide, thereby helping to remove sulfide from the wastewater. At the same time, the sulfide is converted into harmless sulfate to avoid secondary pollution. During the sulfur autotrophic denitrification process, the added sulfur source is oxidized by the sulfur autotrophic bacteria into harmless sulfate substances, which will not increase the sulfide content in the wastewater.

[0019] In addition, phosphate and nitrogen sources serve as nutrients for microbial growth, supporting their growth and metabolic activities. These nutrients are converted into cellular substances or participate in metabolic processes in the microorganisms. In addition, the biofilm formed by sulfur autotrophic bacteria on the surface of the filter material has an interception effect on phosphate and nitrogen sources, preventing them from entering the wastewater with the water flow, and will not enter the wastewater to increase the phosphate and nitrogen content.

[0020] Optionally, the sulfur autotrophic agent is loaded on the activated rubber by dipping, spraying or coating, and the added mass ratio of the sulfur autotrophic agent to the activated rubber is 1:(9-12).

[0021] Optionally, in step S3, the sulfur autotrophic agent comprises elemental sulfur powder and potassium dihydrogen phosphate in a mass ratio of 1:(0.8-1.2), and the sulfur autotrophic agent is loaded on the activated rubber by impregnation. The specific operation is:

[0022] S3-1, dissolving potassium dihydrogen phosphate in water, then adding elemental sulfur powder and stirring to prepare a sulfur autotrophic agent impregnation solution;

[0023] S3-2, placing the activated rubber in a sulfur autotrophic agent impregnation solution for immersion treatment, and then drying to obtain composite rubber particles.

[0024] Optionally, the binder in step S4 is one or more of polyvinyl alcohol and epoxy resin, and the added mass ratio of the composite rubber particles to the binder is 1:(0.2-0.3).

[0025] By adopting the above technical solution, polyvinyl alcohol or epoxy resin is selected as a binder and pressed together with the composite rubber particles. Under the action of high temperature, the binder bonds and shapes the composite rubber particles to form filter balls with certain strength and stability.

[0026] Optionally, after the composite rubber particles are prepared in step S3, a porous conductive polymer coating is formed on the surface thereof. The specific method is as follows:

[0027] S3-3, ultrasonically dispersing the PS microspheres in water to prepare a PS microsphere suspension;

[0028] S3-4, dissolving pyrrole monomer and aminopyrrole monomer in water to prepare a monomer solution, then adding sodium sulfate, and then adding the PS microsphere suspension prepared in step S3-3 to prepare a mixed reaction solution;

[0029] S3-5, adding the initiator solution dropwise to the mixed reaction solution, then adding the composite rubber particles, and reacting at 30-40°C for 2-3 hours;

[0030] S3-6. After the reaction is completed, the modified rubber particles coated with a conductive polymer coating are obtained by filtering, and then the modified rubber particles are washed with tetrahydrofuran to remove the PS microspheres, and then dried to obtain composite rubber particles coated with a porous conductive polymer coating.

[0031] By adopting the above technical solution, the sulfur autotrophic agent is loaded on the activated rubber and then coated with a porous conductive polymer coating. Pyrrole monomers and aminopyrrole monomers are polymerized to form polypyrrole. As a conductive polymer, it has good conductivity, provides an efficient channel for electron transfer, and helps to form a good electron conduction network inside the filter material, so that the filter material can better perform the electrochemical reaction process when used in sewage treatment, improve the poor conductivity of rubber waste, accelerate the coupling of sulfur oxidation and denitrification effects, and improve water treatment efficiency. In addition, the porous structure of the conductive polymer can also provide more attachment sites for subsequent sulfur-oxidizing bacteria to form a stable biofilm. The attachment of a large number of bacteria is conducive to increasing the abundance and activity of microorganisms in the filter material and enhancing the filter material's ability to treat pollutants. More importantly, the formation of the conductive polymer coating provides a certain physical barrier protection for the sulfur autotrophic agent, reducing loss during water treatment.

[0032] Optionally, in step S3-3, the mass ratio of PS microspheres to water is 1:(6-8);

[0033] In step S3-4, the added mass ratio of pyrrole monomer to aminopyrrole monomer is 1:(0.5-0.6), the added amount of water is 2-3 times the mass of the added amount of pyrrole monomer, and the added amount of sodium sulfate is 1-3wt% of the added amount of pyrrole monomer;

[0034] In step S3-5, the initiator solution is an ammonium persulfate solution with a mass concentration of 15-20%, and the amount of ammonium persulfate added is 0.5-1wt% of the pyrrole monomer. The volume ratio of the composite rubber particles to the mixed reaction solution is 1:(4-6).

[0035] By adopting the above-mentioned technical solution, the present application uses a sacrificial template method to prepare a porous conductive polymer coating. Polypyrrole, as a conductive polymer, has excellent electrical conductivity. Aminopyrrole monomer is also added to introduce amino functional groups into the polypyrrole. The amino functional groups can form chemical bonds with the hydroxyl and carboxyl groups on the activated rubber waste, thereby helping the conductive coating to adhere firmly to the rubber waste. This not only provides electrical conductivity and physical barrier protection, but also further improves the mechanical properties and wear resistance of the filter material, extending its service life. Sodium sulfate is used as a dopant. Sulfate groups are embedded between polymer chains, providing additional electrons, thereby enhancing the conductive properties of the polymer.

[0036] Optionally, in step S4, the composite rubber particles are prepared by mixing composite rubber particles with a particle size of 5-7 mm, a particle size of 2-4 mm, and a particle size of 0.5-1 mm in a mass ratio of (3-4): (5-6): 1.

[0037] By adopting the above technical solution, large particles serve as the skeleton support structure, medium particles fill the pores, and small particles increase the packing density, thereby forming a more uniform and rich porous filter material structure while ensuring the mechanical strength of the filter material and having a longer service life.

[0038] Optionally, in step S4, Fenton iron mud and azodicarbonamide are added when the composite rubber particles are mixed with the binder, wherein the amount of Fenton iron mud added is 3-8wt% of the amount of the composite rubber particles added, and the amount of azodicarbonamide added is 1-3wt% of the amount of the composite rubber particles added.

[0039] By adopting the above technical solution, azodicarbonamide is used as a foaming agent. During the pressing process, the foaming agent is decomposed by heat to produce gas, forming bubbles inside the filter ball. As the pressing process proceeds, the bubbles gradually grow and connect with each other to form a filter material with a porous structure. The addition of Fenton iron mud introduces iron elements into the filter material, which can, on the one hand, improve the denitrification capacity of the sulfur autotrophic filter material, and on the other hand, can also simultaneously denitrify and remove phosphorus, thereby improving the water treatment effect. In addition, the addition of iron mud increases the density of the filter material, thereby improving the phenomenon of the filter material floating due to the light weight of the rubber tire particles.

[0040] In a second aspect, the present application provides a sulfur autotrophic filter material, which adopts the following technical solution:

[0041] A sulfur autotrophic filter material is prepared by the preparation method.

[0042] By adopting the above technical solution, the sulfur autotrophic filter material in the present application uses rubber tire waste as a carrier, pre-treats the waste rubber tire particles, activates them, loads the sulfur autotrophic agent, and forms them to prepare a filter material with sulfur autotrophic function, which can efficiently treat sulfur-containing wastewater and realize the resource utilization of waste rubber tires, with good environmental and economic benefits.

[0043] In summary, this application has the following beneficial effects:

[0044] 1. The sulfur autotrophic filter material in this application uses rubber tire waste as a carrier, and the waste rubber tire particles are pretreated, activated, loaded with a sulfur autotrophic agent, and formed to prepare a filter material with sulfur autotrophic function. It can efficiently treat sulfur-containing wastewater and realize the resource utilization of waste rubber tires, with good environmental and economic benefits.

[0045] 2. After the sulfur autotrophic agent is loaded on the activated rubber, it is also coated to form a porous conductive polymer coating. Pyrrole monomers and aminopyrrole monomers are polymerized to form polypyrrole. As a conductive polymer, it has good conductivity, provides an efficient channel for electron transfer, and helps to form a good electron conduction network inside the filter material, so that the filter material can better perform the electrochemical reaction process when used in sewage treatment, improve the poor conductivity of rubber waste, accelerate the coupling of sulfur oxidation and denitrification effects, and improve water treatment efficiency. In addition, the porous structure of the conductive polymer can also provide more attachment sites for subsequent sulfur-oxidizing bacteria to form a stable biofilm. The attachment of a large number of bacteria is conducive to increasing the abundance and activity of microorganisms in the filter material, and enhancing the filter material's ability to treat pollutants. More importantly, the formation of the conductive polymer coating provides a certain physical barrier protection for the sulfur autotrophic agent, reduces loss during water treatment, and increases its service life. DETAILED DESCRIPTION

[0046] The present application is further described in detail below with reference to the examples. It is particularly noted that if no specific conditions are specified in the following examples, the reactions are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0047] Example 1

[0048] A method for preparing sulfur autotrophic filter material based on rubber tire waste comprises the following steps:

[0049] S1, crushing and screening waste rubber tires to obtain 0.5-5mm rubber particle waste;

[0050] S2, using 5wt% sodium hydroxide solution to clean the rubber waste, and then soaking the cleaned rubber waste in 10wt% sulfuric acid solution for 30min to prepare activated rubber;

[0051] S3, loading a sulfur autotrophic agent containing a sulfur source on the activated rubber, and drying to obtain composite rubber particles, specifically the following operations:

[0052] S3-1. Using a mixture of potassium dihydrogen sulfate and elemental sulfur powder as a sulfur autotrophic agent, dissolving potassium dihydrogen phosphate in water, then adding elemental sulfur powder and stirring to prepare a sulfur autotrophic agent impregnation solution, the mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:1;

[0053] S3-2, placing the activated rubber in a sulfur autotrophic agent impregnation solution and immersing it for 50 minutes, with the added mass ratio of sulfur autotrophic agent to activated rubber being 1:10, and then drying it at 60° C. for 2 hours to obtain composite rubber particles;

[0054] S4. Compound rubber particles with a particle size of 2-5 mm are mixed with a binder and pressed to form filter balls. The mass ratio of compound rubber particles to binder is 1:0.2, and polyvinyl alcohol is used as the binder.

[0055] S5. Thiobacillus denitrificans (ATCC 23644) was used as the sulfur-oxidizing bacterium. The lyophilized powder of Thiobacillus denitrificans was activated (inoculated into sodium thiosulfate medium (5 g / L sodium thiosulfate, 3 g / L sodium nitrate, 1 g / L KH2PO4, 0.5 g / L MgSO4・7H2O, pH 7.2) and cultured at 30°C under aerobic conditions for 24 h until the culture solution became turbid). The culture was then expanded (the activated culture solution was transferred to fresh sodium thiosulfate medium at a ratio of 1:10 and continued to be cultured until the logarithmic growth phase). The concentration was then adjusted with physiological saline to 5 × 10 8 CFU / mL of sulfur-oxidizing bacterial suspension;

[0056] The filter balls prepared in step S4 were sterilized at high temperature and high pressure and then placed in a sulfur-oxidizing bacteria suspension. They were statically cultured at a temperature of 25° C. for 36 hours. During this period, they were gently shaken at intervals to allow the bacteria to initially adhere to the surface of the filter balls. The filter balls were then transferred to a dynamic culture device and cultured continuously for 7 days at a hydraulic load of 0.5 m³ / (m²・h) at a temperature of 25° C. using simulated sulfur-containing wastewater (sodium sulfide concentration of 100 mg / L, sodium nitrate concentration of 50 mg / L, and potassium dihydrogen phosphate concentration of 5 mg / L). Dynamic culture enables sulfur-oxidizing bacteria to better adapt to the actual water treatment environment, form a more stable and efficient biofilm, and improve the filter material's sulfide removal efficiency and shock load resistance, thereby producing a sulfur-autotrophic filter material.

[0057] Example 2

[0058] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that:

[0059] S2, using 8wt% sodium hydroxide solution to wash the rubber waste, and then soaking the washed rubber waste in 15wt% sulfuric acid solution for 40min to prepare activated rubber;

[0060] S3, loading a sulfur autotrophic agent containing a sulfur source on the activated rubber, and drying to obtain composite rubber particles, specifically the following operations:

[0061] S3-1. Using a mixture of potassium dihydrogen sulfate and elemental sulfur powder as a sulfur autotrophic agent, dissolving potassium dihydrogen phosphate in water, then adding elemental sulfur powder and stirring to prepare a sulfur autotrophic agent impregnation solution, wherein the mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:0.8;

[0062] S3-2, placing the activated rubber in a sulfur autotrophic agent impregnation solution and immersing it for 40 minutes, with the added mass ratio of the sulfur autotrophic agent to the activated rubber being 1:9, and then drying it at 60° C. for 2 hours to obtain composite rubber particles;

[0063] S4. The composite rubber particles are mixed with a binder and then pressed to form filter balls. The mass ratio of the composite rubber particles to the binder is 1:0.2, and the binder is an epoxy resin, specifically bisphenol A epoxy resin E-51.

[0064] The remaining operations are the same as in Example 1.

[0065] Example 3

[0066] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that:

[0067] S2, using 10wt% sodium hydroxide solution to clean the rubber waste, and then soaking the cleaned rubber waste in 20wt% sulfuric acid solution for 20min to prepare activated rubber;

[0068] S3, loading a sulfur autotrophic agent containing a sulfur source on the activated rubber, and drying to obtain composite rubber particles, specifically the following operations:

[0069] S3-1. Using a mixture of potassium dihydrogen sulfate and elemental sulfur powder as a sulfur autotrophic agent, dissolving potassium dihydrogen phosphate in water, then adding elemental sulfur powder and stirring to prepare a sulfur autotrophic agent impregnation solution, the mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:1.2;

[0070] S3-2, placing the activated rubber in a sulfur autotrophic agent impregnation solution and immersing it for 60 minutes, with the added mass ratio of sulfur autotrophic agent to activated rubber being 1:12, and then drying it at 60° C. for 2 hours to obtain composite rubber particles;

[0071] S4. The composite rubber particles are mixed with a binder and then pressed to form filter balls. The mass ratio of the composite rubber particles to the binder is 1:0.3, and polyvinyl alcohol is used as the binder.

[0072] The remaining operations are the same as in Example 1.

[0073] Example 4

[0074] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that:

[0075] In step S3-2, the activated rubber is immersed in the sulfur autotrophic agent impregnation solution under ultrasonic conditions with a power of 100 W;

[0076] In step S4, the composite rubber particles are selected from composite rubber particles with a particle size of 5-7 mm, a particle size of 2-4 mm, and a particle size of 0.5-1 mm, and are mixed with a binder in a mass ratio of (3-4): (5-6): 1; and in step S4, the composite rubber particles and the binder are mixed and then pressed into filter balls, which are then heat-treated at 120° C. for 1 hour to improve the mechanical strength and stability of the balls.

[0077] Example 5

[0078] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method of Example 1, except that in step S3, a porous conductive polymer coating is formed on the surface of the composite rubber particles after the sulfur autotrophic agent is loaded on the activated rubber. The specific method is as follows:

[0079] S3-3, ultrasonically dispersing PS microspheres (particle size 0.1-0.2 μm) in 7 times the mass of water to prepare a PS microsphere suspension;

[0080] S3-4, mixing pyrrole monomer and 1-aminopyrrole monomer in a mass ratio of 1:0.5 and dissolving in water, wherein the amount of water added is 2 times the mass of the amount of pyrrole monomer added, to prepare a monomer solution, and then adding sodium sulfate, wherein the amount of sodium sulfate added is 2wt% of the amount of pyrrole monomer added, and adding the PS microsphere suspension prepared in step S3-3 to prepare a mixed reaction solution;

[0081] S3-5, dropwise adding a 15% ammonium persulfate solution to the mixed reaction solution, where the amount of ammonium persulfate added is 0.8 wt % of the pyrrole monomer, and then adding the composite rubber particles prepared in step S3-2, where the volume ratio of the composite rubber particles to the mixed reaction solution is 1:5, and reacting at 35° C. for 2.5 h;

[0082] S3-6. After the reaction is completed, the modified rubber particles coated with a conductive polymer coating are obtained by filtering, and then the modified rubber particles are washed with tetrahydrofuran to remove the PS microspheres, and then dried to obtain composite rubber particles coated with a porous conductive polymer coating.

[0083] Example 6

[0084] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method of Example 1, except that in step S3, a porous conductive polymer coating is formed on the surface of the composite rubber particles after the sulfur autotrophic agent is loaded on the activated rubber. The specific method is as follows:

[0085] S3-3, ultrasonically dispersing PS microspheres (particle size 0.1-0.2 μm) in 6 times the mass of water to prepare a PS microsphere suspension;

[0086] S3-4, mixing pyrrole monomer and 3-aminopyrrole monomer in a mass ratio of 1:0.5 and dissolving in water, wherein the amount of water added is 2 times the mass of the amount of pyrrole monomer added, to prepare a monomer solution, and then adding sodium sulfate, wherein the amount of sodium sulfate added is 1wt% of the amount of pyrrole monomer added, and adding the PS microsphere suspension prepared in step S3-3 to prepare a mixed reaction solution;

[0087] S3-5, dropwise adding a 15% ammonium persulfate solution to the mixed reaction solution, where the amount of ammonium persulfate added is 0.5 wt % of the pyrrole monomer, and then adding the composite rubber particles prepared in step S3-2, where the volume ratio of the composite rubber particles to the mixed reaction solution is 1:4, and reacting at 30° C. for 3 h;

[0088] S3-6. After the reaction is completed, the modified rubber particles coated with a conductive polymer coating are obtained by filtering, and then the modified rubber particles are washed with tetrahydrofuran to remove the PS microspheres, and then dried to obtain composite rubber particles coated with a porous conductive polymer coating.

[0089] Example 7

[0090] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method of Example 1, except that in step S3, a porous conductive polymer coating is formed on the surface of the composite rubber particles after the sulfur autotrophic agent is loaded on the activated rubber. The specific method is as follows:

[0091] S3-3, ultrasonically dispersing PS microspheres (particle size 0.1-0.2 μm) in 8 times the mass of water to prepare a PS microsphere suspension;

[0092] S3-4, mixing a pyrrole monomer and a 1-aminopyrrole monomer in a mass ratio of 1:0.6 and dissolving the mixture in water, wherein the amount of water added is 3 times the mass of the amount of the pyrrole monomer added, to prepare a monomer solution, and then adding sodium sulfate, wherein the amount of sodium sulfate added is 3 wt % of the amount of the pyrrole monomer added, and adding the PS microsphere suspension prepared in step S3-3 to prepare a mixed reaction solution;

[0093] S3-5, dropwise adding a 20% ammonium persulfate solution to the mixed reaction solution, where the amount of ammonium persulfate added is 1 wt% of the pyrrole monomer, and then adding the composite rubber particles prepared in step S3-2, where the volume ratio of the composite rubber particles to the mixed reaction solution is 1:6, and reacting at 40° C. for 2 h;

[0094] S3-6. After the reaction is completed, the modified rubber particles coated with a conductive polymer coating are obtained by filtering, and then the modified rubber particles are washed with tetrahydrofuran to remove the PS microspheres, and then dried to obtain composite rubber particles coated with a porous conductive polymer coating.

[0095] Example 8

[0096] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 5, except that in step S3-4, an equal amount of 1-aminopyrrole monomer is replaced by pyrrole monomer.

[0097] Example 9

[0098] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that:

[0099] In step S4, Fenton iron mud and azodicarbonamide are added when the composite rubber particles are mixed with the binder. The amount of Fenton iron mud (iron content is 8%) added is 5wt% of the amount of the composite rubber particles added, and the amount of azodicarbonamide added is 2wt% of the amount of the composite rubber particles added.

[0100] Example 10

[0101] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that in step S4, Fenton iron mud and azodicarbonamide are also added when the composite rubber particles are mixed with the binder, the amount of Fenton iron mud added is 3wt% of the amount of the composite rubber particles added, and the amount of azodicarbonamide added is 1wt% of the amount of the composite rubber particles added.

[0102] Example 11

[0103] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that in step S4, Fenton iron mud and azodicarbonamide are also added when the composite rubber particles are mixed with the binder, the amount of Fenton iron mud added is 8wt% of the composite rubber particles, and the amount of azodicarbonamide added is 3wt% of the composite rubber particles.

[0104] Comparative Example 1

[0105] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that step S2 is not performed.

[0106] Comparative Example 2

[0107] A method for preparing a sulfur autotrophic filter material based on rubber tire waste is carried out according to the method in Example 1, except that in step S2, the material is not impregnated with dilute sulfuric acid after washing with sodium hydroxide.

[0108] Performance testing

[0109] The sulfur autotrophic filter materials prepared in the examples and comparative examples of the present application were placed on a filter plate to form a filter layer, and then simulated sulfur-containing wastewater was introduced into the filter tank for treatment for 1 hour and then discharged. The removal rates of sulfide and total nitrogen in the wastewater by the sulfur autotrophic filter materials were statistically analyzed, and the statistical results are shown in Table 1 below. The removal rates of sulfide and total nitrogen after 20 cycles were statistically analyzed, and the statistical results are shown in Table 2. The sodium sulfide concentration in the simulated sulfur-containing wastewater was 200 mg / L, the ammonium chloride concentration was 480 mg / L, the potassium nitrate content was 250 mg / L, the ferrous sulfate content was 80 mg / L, and the disodium hydrogen phosphate content was 30 mg / L.

[0110] Table 1: First desulfurization and denitrification effects

[0111]

[0112] Table 2: Desulfurization and denitrification effects after 20 cycles

[0113]

[0114] Referring to the test results of Table 1 and Table 2 above, the sulfur autotrophic filter material prepared in the embodiment of the present application has good desulfurization and denitrification performance, and has good desulfurization and denitrification performance after multiple cycles, and has a long service life. Referring to the test results of Example 1 and Example 4, the rubber is activated by immersion treatment under ultrasonic conditions to improve the loading efficiency of the sulfur autotrophic agent, and composite rubber particles of different particle sizes are mixed to enhance the mechanical strength and stability of the filter ball. The sulfur autotrophic filter material prepared in Example 4 has better water treatment results. Combined with the test results of Examples 5-7, after the sulfur autotrophic agent is loaded on the activated rubber, a porous conductive polymer coating is also coated on its surface, which helps to improve its electrochemical reaction and improve the water treatment effect. At the same time, the formation of the coating also helps to physically shield the sulfur autotrophic agent. Barrier protection, achieving sustained release, and it has excellent treatment effect after multiple cycles, thereby increasing the service life of the filter material. Combined with the test results in Example 8, when coating the porous conductive polymer coating, when only pyrrole monomer is added to prepare the polypyrrole conductive polymer, the additional adhesion provided by the amino functional group is lacking. Compared with Example 1 in which pyrrole monomer and aminopyrrole monomer are combined, its treatment effect is reduced, especially after multiple cycles, its treatment capacity is significantly reduced. Combined with the test results in Examples 9-11, when Fenton iron mud and azodicarbonamide are added when the composite rubber particles are mixed with the binder and then pressed into shape, the water treatment effect is also improved compared with Example 1, which is related to the effect of the addition of the above substances on conductivity and porous structure establishment.

[0115] Referring again to the test results in Example 1 and Comparative Example 1, when the rubber tire waste is directly loaded with the sulfur autotrophic agent, the surface active sites are insufficient, resulting in a significant reduction in its water treatment effect, especially after multiple recycling. Combined with the case of Comparative Example 2, when the rubber tire waste is only washed with alkali without undergoing dilute sulfuric acid immersion activation treatment, the water treatment effect is poor due to the lack of the process of sulfuric acid introducing oxygen-containing functional groups.

[0116] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing sulfur autotrophic filter material based on rubber tire waste, characterized in that: The following steps are involved: S1. Crushing and screening waste rubber tires to produce rubber granules; S2. Alkaline-washing and then acid-washing the waste rubber to produce activated rubber; S3. Loading a sulfur autotrophic agent containing a sulfur source on the activated rubber and drying the activated rubber to produce composite rubber particles; S4. Mixing the composite rubber particles with a binder and pressing the mixture to form filter balls; S5. Inoculating the filter balls with sulfur-oxidizing bacteria and activating the bacteria to produce sulfur autotrophic filter media; After the composite rubber particles are prepared in step S3, a porous conductive polymer coating is also formed on the surface of the composite rubber particles. The specific method is as follows: S3-3, ultrasonically dispersing PS microspheres in water to prepare a PS microsphere suspension; S3-4, dissolving pyrrole monomer and aminopyrrole monomer in water to prepare a monomer solution, then adding sodium sulfate, and then adding the PS microsphere suspension prepared in step S3-3 to prepare a mixed reaction liquid; S3-5, dropwise adding an initiator solution to the mixed reaction liquid, and then adding the composite rubber particles, and reacting at 30-40°C for 2-3 hours; S3-6, after the reaction is completed, filtering to obtain modified rubber particles coated with the conductive polymer coating, then washing the modified rubber particles with tetrahydrofuran to remove the PS microspheres, and then drying to obtain composite rubber particles coated with a porous conductive polymer coating.

2. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: The specific operation of alkali washing in step S2 is to wash the rubber waste in a 5-10wt% sodium hydroxide solution, and then soak the rubber waste in a 10-20wt% sulfuric acid solution for 20-40 minutes to obtain activated rubber.

3. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: The sulfur autotrophic agent in step S3 includes a sulfur source and a nutrient in a mass ratio of 1:(0.8-1.2), the sulfur source includes one or more of elemental sulfur, sodium sulfide and sodium thiosulfate, and the nutrient is selected from one or more of phosphate and nitrogen source.

4. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: The sulfur autotrophic agent is loaded on the activated rubber by dipping, spraying or coating, and the added mass ratio of the sulfur autotrophic agent to the activated rubber is 1:(9-12).

5. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: In step S3, the sulfur autotrophic agent includes elemental sulfur powder and potassium dihydrogen phosphate in a mass ratio of 1: (0.8-1.2). The sulfur autotrophic agent is loaded on the activated rubber by impregnation. The specific operation is: S3-1, dissolving potassium dihydrogen phosphate in water, then adding elemental sulfur powder, stirring, to obtain a sulfur autotrophic agent impregnation solution; S3-2, placing the activated rubber in the sulfur autotrophic agent impregnation solution for immersion treatment, and then drying to obtain composite rubber particles.

6. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: The binder in step S4 is selected from one or more of polyvinyl alcohol and epoxy resin, and the added mass ratio of the composite rubber particles to the binder is 1:(0.2-0.3).

7. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: In step S3-3, the mass ratio of PS microspheres to water is 1:(6-8); in step S3-4, the mass ratio of pyrrole monomer to aminopyrrole monomer is 1:(0.5-0.6), the amount of water added is 2-3 times the mass of the pyrrole monomer added, and the amount of sodium sulfate added is 1-3wt% of the pyrrole monomer added; in step S3-5, the initiator solution is an ammonium persulfate solution with a mass concentration of 15-20%, and the amount of ammonium persulfate added is 0.5-1wt% of the pyrrole monomer. The volume ratio of the composite rubber particles to the mixed reaction solution is 1:(4-6).

8. The method for preparing sulfur autotrophic filter material based on rubber tire waste according to claim 1, characterized in that: In step S4, the composite rubber particles are prepared by mixing composite rubber particles with a particle size of 5-7 mm, a particle size of 2-4 mm, and a particle size of 0.5-1 mm in a mass ratio of (3-4): (5-6):

1.

9. A sulfur autotrophic filter material obtained by the method according to any one of claims 1 to 8.

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