Method for preparing sulfur autotrophic filter material based on rubber tire waste and prepared sulfur autotrophic filter material

Abstract

The invention relates to the field of water treatment, and particularly discloses a method for preparing a sulfur autotrophic filter material based on rubber tire waste and the prepared sulfur autotrophic filter material, and the method comprises the following steps: S1, crushing and screening waste rubber tires to prepare rubber particle waste; s2, the rubber waste is subjected to acid pickling after alkali washing, and activated rubber is prepared; 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 to form filter material balls; s5, sulfur oxidizing bacteria are inoculated on the filter material balls and then activated, and the sulfur autotrophic filter material is obtained.The invention further discloses the sulfur autotrophic filter material prepared through the method, the rubber tire waste is applied to prepare the water treatment filter material with the sulfur autotrophic function, the problem of environmental pollution caused by waste tires is solved, and the water treatment efficiency is improved. Meanwhile, the cost of the sulfur autotrophic filter material is reduced.

Description

Technical Field

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

[0002] With the rapid development of the global automotive industry, the number of waste rubber tires has been increasing year by year. How to properly dispose of these waste tires has become a severe environmental challenge. Traditional disposal methods mainly include landfilling and incineration. However, these methods not only consume a large amount of land resources and energy but also easily cause secondary pollution, such as soil pollution, air pollution, etc. Therefore, it is particularly important to find an efficient and environmentally friendly method for recycling waste tires.

[0003] Meanwhile, with the acceleration of the industrialization process, the problem of water resource pollution has become increasingly serious, especially the discharge of sulfur-containing wastewater has caused great damage to the environment. In the field of water treatment, filter media, as one of the key materials for removing pollutants in water, its performance directly affects the effect of water purification. However, most filter media on the market currently have problems such as high cost and low efficiency when treating sulfur-containing wastewater, making it difficult to meet the actual application requirements.

[0004] In recent years, sulfur autotrophic filter media, as a new type of functional material, has received extensive attention. Sulfur autotrophic filter media can use sulfide as an electron donor and oxidize sulfide to 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 waste rubber tires to filter media for water treatment with sulfur autotrophic function can not only solve the environmental pollution problem of waste tires but also provide a new solution for the water treatment industry. Summary of the Invention

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

[0006] In the first aspect, the present application provides a method for preparing sulfur autotrophic filter media based on waste rubber tires, adopting the following technical solution: A method for preparing sulfur autotrophic filter media based on waste rubber tires, comprising the following steps: S1. Crushing and screening waste rubber tires to obtain rubber particle waste; S2. Alkaline washing and then acid washing the rubber waste to obtain activated rubber; S3. Loading a sulfur autotrophic agent containing a sulfur source onto the activated rubber and drying to obtain composite rubber particles; S4. Mix the composite rubber particles with a binder and press them to form filter media balls; S5. Inoculate the filter media balls with sulfur-oxidizing bacteria and activate them to obtain sulfur autotrophic filter media.

[0007] By adopting the above technical solution, in this application, waste rubber tires are used as raw materials. After being crushed, they are alkali-washed to remove surface oil stains, and then acid-washed to treat the surface of the rubber particles, improving the surface roughness and specific surface area, providing binding sites for the sulfur autotrophic agent. Then, the sulfur autotrophic agent is loaded, and then bonded and pressed into filter media and inoculated with microorganisms for activation to obtain sulfur autotrophic filter media. This not only realizes the resource utilization of waste rubber tires and reduces environmental pollution, but also through the treatment of the sulfur autotrophic agent and sulfur-oxidizing bacteria, the obtained filter media has the function of sulfur autotrophy. When wastewater passes through the sulfur autotrophic filter media, the pollutants in the wastewater are first adsorbed by the filter media, and then the sulfur-oxidizing bacteria convert the pollutants into harmless substances using the sulfur autotrophic agent as energy, removing sulfides and nitrogen in the wastewater, efficiently treating sulfur-containing wastewater, reducing the water treatment cost. Moreover, the addition of the binder forms a three-dimensional network structure during the pressing process, enhancing the mechanical strength. The obtained filter media has good mechanical strength and chemical stability, is suitable for various water treatment scenarios, and the preparation process is simple and easy to scale up production.

[0008] In addition, in this application, rubber tire waste is selected as the carrier. On the one hand, the elasticity of the rubber enables the filter media obtained to better maintain structural stability during backwashing, not easily break, and at the same time avoid the shedding of the biofilm, maintaining long-term pore stability, thereby improving the service life and long-term use effect of the filter media.

[0009] Optionally, the specific operation of the alkali washing in step S2 is to wash the rubber waste in a 5-10 wt% sodium hydroxide solution, and then soak the rubber waste in a 10-20 wt% sulfuric acid solution for 20-40 min to obtain activated rubber.

[0010] By adopting the above technical solution, first, the sodium hydroxide is used to remove the surface grease, impurities, etc. of the rubber waste, and corrode part of the amorphous rubber chains to form a rough surface. Then, it is impregnated and treated in the sulfuric acid solution. Oxygen-containing functional groups such as carboxyl and hydroxyl are introduced through sulfuric acid to enhance the surface chemical reactivity and hydrophilicity of the rubber waste, providing binding sites for the sulfur autotrophic agent.

[0011] 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, sulfides such as sodium sulfide or sodium thiosulfate, and the nutrient is selected from one or more of phosphates and nitrogen sources.

[0012] By adopting the above technical solution, in this application, the sulfur source serves as the necessary energy source for sulfur autotrophic bacteria, enabling the sulfur autotrophic bacteria to use the sulfur source as an electron donor and reducing nitrate nitrogen in water to nitrogen gas through autotrophic denitrification and other reactions, thereby achieving nitrogen removal from wastewater. 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 sulfides, thus contributing to the removal of sulfides in wastewater. Meanwhile, the sulfides are converted into harmless sulfates, avoiding secondary pollution. During the sulfur autotrophic denitrification process, the added sulfur source is oxidized by sulfur autotrophic bacteria into harmless sulfate substances and will not increase the sulfide content in the wastewater.

[0013] In addition, phosphate and nitrogen sources, as microbial growth nutrients, support their growth and metabolic activities. These nutrients are converted into cell substances or participate in the metabolic process in microorganisms. Coupled with the interception effect of the biofilm formed by sulfur autotrophic bacteria on the surface of the filter material on phosphate and nitrogen sources, preventing them from entering the wastewater with the water flow and not entering the wastewater to increase the phosphate and nitrogen content.

[0014] Optionally, the sulfur autotroph is loaded on the activated rubber by means of impregnation, spraying or coating, and the added mass ratio of the sulfur autotroph to the activated rubber is 1:(9 - 12).

[0015] Optionally, in step S3, the sulfur autotroph includes elemental sulfur powder and potassium dihydrogen phosphate with a mass ratio of 1:(0.8 - 1.2), and the sulfur autotroph is loaded on the activated rubber by impregnation. The specific operation is as follows: S3-1. Dissolve potassium dihydrogen phosphate in water, then add elemental sulfur powder and stir to obtain the sulfur autotroph impregnation solution; S3-2. Immerse the activated rubber in the sulfur autotroph impregnation solution for impregnation treatment, and then dry to obtain composite rubber particles.

[0016] Optionally, 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).

[0017] By adopting the above technical solution, polyvinyl alcohol or epoxy resin is selected as the binder to be pressed and formed with the composite rubber particles. Under the action of high temperature during pressing, the binder bonds and forms the composite rubber particles to form a filter ball with a certain strength and stability.

[0018] Optionally, after the composite rubber particles are prepared in step S3, a porous conductive polymer coating is also formed on their surface. The specific method is as follows: S3-3. Ultrasonically disperse PS microspheres in water to obtain a PS microsphere suspension; S3-4. Dissolve pyrrole monomer and aminopyrrole monomer in water to obtain a monomer solution. Then, after adding sodium sulfate, add the PS microsphere suspension prepared in step S3-3 to obtain a mixed reaction solution; S3-5. Dropwise add an initiator solution to the mixed reaction solution, then add composite rubber particles, and react at 30-40 °C for 2-3 h; S3-6. After the reaction is completed, filter to obtain modified rubber particles coated with a conductive polymer coating. Then, use tetrahydrofuran to wash the modified rubber particles to remove the PS microspheres, and then dry to obtain composite rubber particles coated with a porous conductive polymer coating.

[0019] By adopting the above technical solution, the sulfur autotroph is loaded on the activated rubber and then coated with a porous conductive polymer coating. Polypyrrole is formed by polymerizing pyrrole monomer and aminopyrrole monomer. As a conductive polymer, it has good conductivity and provides an efficient channel for electron transfer, which helps to form a good electron conduction network inside the filter material. When the filter material is applied to sewage treatment, it can better the electrochemical reaction process, improve the poor conductivity of rubber waste, accelerate the coupling of sulfur oxidation and denitrification effects, and improve the 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 beneficial to increasing the microbial abundance and activity in the filter material and enhancing the treatment ability of the filter material for pollutants. More importantly, the formation of the conductive polymer coating provides a certain physical barrier protection for the sulfur autotroph and reduces the loss during water treatment.

[0020] Optionally, in step S3-3, the added mass ratio of PS microspheres to water is 1:(6-8); In step S3-4, the added mass ratio of pyrrole monomer to aminopyrrole monomer is 1:(0.5-0.6), and the water addition amount is 2-3 mass times the pyrrole monomer addition amount, and the sodium sulfate addition amount is 1-3 wt% of the pyrrole monomer addition amount; In step S3-5, the initiator solution is an ammonium persulfate solution with a mass concentration of 15-20%, and the ammonium persulfate addition amount is 0.5-1 wt% of the pyrrole monomer, and the added volume ratio of the composite rubber particles to the mixed reaction solution is 1:(4-6).

[0021] By adopting the above technical solution, in this application, a sacrificial template method is used to prepare a porous conductive polymer coating. Polypyrrole, as a conductive polymer, has excellent electrical conductivity, and an aminopyrrole monomer is also added. In this way, amino functional groups can be introduced into polypyrrole. Chemical bonding can be formed between the amino functional groups and the hydroxyl and carboxyl groups on the activated rubber waste, which helps the conductive coating to adhere firmly to the rubber waste. It not only plays a role in electrical conduction and physical barrier protection, but also can further improve the mechanical properties and wear resistance of the filter material, and has a longer service life. Sodium sulfate is used as a dopant, and sulfate ions are embedded between the polymer chains to provide additional electron donors, thereby enhancing the electrical conductivity of the polymer.

[0022] Optionally, in step S4, the composite rubber particles are prepared by mixing composite rubber particles with particle sizes of 5-7 mm, 2-4 mm, and 0.5-1 mm in a mass ratio of (3-4):(5-6):1.

[0023] By adopting the above technical solution, the large particles serve as the skeleton support structure, the medium particles fill the pores, and the small particles increase the packing density, thus forming a more uniform and porous filter material structure while ensuring the mechanical strength of the filter material and having a longer service life.

[0024] Optionally, when the composite rubber particles are mixed with the binder in step S4, Fenton iron sludge and azodicarbonamide are also added. The addition amount of Fenton iron sludge is 3-8 wt% of the addition amount of the composite rubber particles, and the addition amount of azodicarbonamide is 1-3 wt% of the addition amount of the composite rubber particles.

[0025] By adopting the above technical solution, azodicarbonamide is used as a foaming agent. During the pressing process, the foaming agent decomposes when heated to generate gas, forming bubbles inside the filter material balls. As the pressing process progresses, the bubbles gradually grow and connect with each other, forming a filter material with a porous structure. The addition of Fenton iron sludge introduces iron elements into the filter material. On the one hand, it can improve the denitrification ability of the sulfur autotrophic filter material, and on the other hand, it can also simultaneously remove nitrogen and phosphorus, improving the water treatment effect. Moreover, the addition of iron sludge increases the density of the filter material, improving the phenomenon of the filter material floating due to the light weight of the rubber tire particles.

[0026] In a second aspect, this application provides a sulfur autotrophic filter material, adopting the following technical solution: A sulfur autotrophic filter material is prepared by the above preparation method.

[0027] By adopting the above technical solution, in this application, the sulfur autotrophic filter material uses rubber tire waste as a carrier, pre-treats, activates, loads a sulfur autotrophic agent, and forms a filter material with sulfur autotrophic function, which can efficiently treat sulfur-containing wastewater and simultaneously realize the resource utilization of waste rubber tires, having good environmental and economic benefits.

[0028] In summary, the present application has the following beneficial effects: 1. In the present application, the sulfur autotrophic filter material uses waste rubber tires as a carrier. The waste rubber tire particles are pretreated, activated, loaded with sulfur autotrophic agents, and formed into a filter material with sulfur autotrophic function, which can efficiently treat sulfur-containing wastewater and at the same time realize the resource utilization of waste rubber tires, having good environmental and economic benefits; 2. After the sulfur autotrophic agent is loaded on the activated rubber, a porous conductive polymer coating is also coated. Polypyrrole is formed by polymerizing pyrrole monomer and aminopyrrole monomer. As a conductive polymer, it has good conductivity and provides an efficient channel for electron transfer, which helps to form a good electron conduction network inside the filter material, enabling the filter material to better carry out the electrochemical reaction process when applied to sewage treatment, improving the poor conductivity of rubber waste, accelerating the coupling of sulfur oxidation and denitrification effects, and improving the 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 beneficial to increasing the microbial abundance and activity in the filter material, enhancing the pollutant treatment ability of the filter material. More importantly, the formation of the conductive polymer coating provides a certain physical barrier protection for the sulfur autotrophic agent, reducing the loss during water treatment and increasing the service life. Specific Embodiments

[0029] The following further elaborates on the present application in conjunction with embodiments. It should be specifically noted that: for those conditions not specified in the following embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. Except as otherwise specifically stated, the raw materials used in the following embodiments can all be obtained from ordinary commercial sources.

[0030] Example 1 A method for preparing a sulfur autotrophic filter material based on waste rubber tires includes the following steps: S1. The waste rubber tires are crushed and screened to obtain rubber particle waste with a size of 0.5 - 5 mm; S2. The rubber waste is washed with a 5 wt% sodium hydroxide solution, and then the washed rubber waste is soaked in a 10 wt% sulfuric acid solution for 30 min to obtain activated rubber; S3. The sulfur autotrophic agent containing a sulfur source is loaded on the activated rubber and dried to obtain composite rubber particles. The specific operation is as follows: S3-1. A mixture of potassium dihydrogen sulfate and elemental sulfur powder is used as the sulfur autotrophic agent. Potassium dihydrogen phosphate is dissolved in water, and then elemental sulfur powder is added and stirred to obtain a sulfur autotrophic agent impregnation solution. The added mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:1; S3-2. Immerse the activated rubber in the sulfur autotrophic agent impregnation solution for 50 min. The added mass ratio of the sulfur autotrophic agent to the activated rubber is 1:10. Then dry it at 60 °C for 2 h to obtain composite rubber particles. S4. Select composite rubber particles with a particle size of 2 - 5 mm, mix them with a binder, and press them to form filter media balls. The added mass ratio of the composite rubber particles to the binder is 1:0.2, and the binder is polyvinyl alcohol. S5. Use Thiobacillus denitrificans, numbered ATCC23644, as the sulfur-oxidizing bacteria. Activate the freeze-dried powder of Thiobacillus denitrificans (inoculate it into a sodium thiosulfate medium (sodium thiosulfate 5 g / L, sodium nitrate 3 g / L, KH2PO4 1 g / L, MgSO4·7H2O 0.5 g / L, pH 7.2), and culture it at 30 °C under aerobic conditions for 24 h until the bacterial liquid becomes turbid) and then expand the culture (transfer the activated bacterial liquid to a fresh sodium thiosulfate medium at a ratio of 1:10 and continue to culture until the logarithmic growth phase). Then adjust it with physiological saline to obtain a sulfur-oxidizing bacteria suspension with a concentration of 5×10 8 CFU / mL. After subjecting the filter media balls prepared in step S4 to high-temperature and high-pressure sterilization treatment, place them in the sulfur-oxidizing bacteria suspension and statically culture them at 25 °C for 36 h. During this period, gently shake them every once in a while to make the bacteria initially attach to the surface of the filter media balls. Then transfer the filter media balls to a dynamic culture device, and by simulating sulfur-containing wastewater (sodium sulfide concentration is 100 mg / L, sodium nitrate concentration is 50 mg / L, potassium dihydrogen phosphate concentration is 5 mg / L), at 25 °C, continuously culture them for 7 days with a hydraulic load of 0.5 m³ / (m²·h). Dynamic culture can enable the sulfur-oxidizing bacteria to better adapt to the actual water treatment environment, form a more stable and efficient biofilm, improve the removal efficiency of sulfide by the filter media and the anti-shock load capacity, and obtain the sulfur autotrophic filter media.

[0031] Example 2 A method for preparing sulfur autotrophic filter media based on waste rubber tires is carried out according to the method in Example 1, with the difference that S2. Wash the waste rubber with an 8 wt% sodium hydroxide solution, and then soak the washed waste rubber in a 15 wt% sulfuric acid solution for 40 min to obtain activated rubber. S3. Load the sulfur autotrophic agent containing a sulfur source on the activated rubber and dry it to obtain composite rubber particles. The specific operation is as follows; S3-1. Use a mixture of potassium dihydrogen phosphate and elemental sulfur powder as the sulfur autotrophic agent. Dissolve potassium dihydrogen phosphate in water, then add elemental sulfur powder and stir to obtain the sulfur autotrophic agent impregnation solution. The added mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:0.8. S3-2. Immerse the activated rubber in the sulfur autotrophic agent impregnation solution for 40 min. The added mass ratio of the sulfur autotrophic agent to the activated rubber is 1:9. Then dry it at 60 °C for 2 h to obtain composite rubber particles. S4. Mix the composite rubber particles with a binder and press them to form filter media balls. The added mass ratio of the composite rubber particles to the binder is 1:0.2, and the binder selected is epoxy resin, specifically bisphenol A type epoxy resin E-51.

[0032] The remaining operations are the same as those in Example 1.

[0033] Example 3 A method for preparing sulfur autotrophic filter media based on waste rubber tires is carried out according to the method in Example 1, except that S2. Clean the waste rubber with a 10 wt% sodium hydroxide solution, and then immerse the cleaned waste rubber in a 20 wt% sulfuric acid solution for 20 min to obtain activated rubber. S3. Load the sulfur autotrophic agent containing a sulfur source onto the activated rubber and dry it to obtain composite rubber particles. The specific operation is as follows; S3-1. Use a mixture of potassium dihydrogen sulfate and elemental sulfur powder as the sulfur autotrophic agent. Dissolve potassium dihydrogen phosphate in water, and then add elemental sulfur powder and stir to obtain the sulfur autotrophic agent impregnation solution. The added mass ratio of elemental sulfur powder to potassium dihydrogen phosphate is 1:1.2. S3-2. Immerse the activated rubber in the sulfur autotrophic agent impregnation solution for 60 min. The added mass ratio of the sulfur autotrophic agent to the activated rubber is 1:12. Then dry it at 60 °C for 2 h to obtain composite rubber particles. S4. Mix the composite rubber particles with a binder and press them to form filter media balls. The added mass ratio of the composite rubber particles to the binder is 1:0.3, and the binder selected is polyvinyl alcohol.

[0034] The remaining operations are the same as those in Example 1.

[0035] Example 4 A method for preparing sulfur autotrophic filter media based on waste rubber tires is carried out according to the method in Example 1, except that When the activated rubber is immersed in the sulfur autotrophic agent impregnation solution in step S3-2, it is carried out under ultrasonic conditions with a power of 100 W. In step S4, the composite rubber particles selected are a mixture of composite rubber particles with particle sizes of 5-7 mm, 2-4 mm, and 0.5-1 mm in a mass ratio of (3-4):(5-6):1 and mixed with the binder; and in step S4, after the composite rubber particles and the binder are mixed and pressed into filter media balls, they are also heat-treated at 120 °C for 1 h to improve the mechanical strength and stability of the media balls.

[0036] Example 5 A method for preparing sulfur autotrophic filter media from waste rubber tires is carried out according to the method in Example 1. The difference is that after the sulfur autotrophic agent is loaded on the activated rubber to obtain composite rubber particles in step S3, a porous conductive polymer coating is further formed on its surface. The specific method is as follows: S3-3: Ultrasonically disperse PS microspheres (particle size 0.1 - 0.2 μm) in 7 times the mass of water to obtain a PS microsphere suspension; S3-4: Mix pyrrole monomer and 1-aminopyrrole monomer in a mass ratio of 1:0.5 and dissolve them in water. The water addition amount is 2 times the mass of the pyrrole monomer addition amount to obtain a monomer solution. Then add sodium sulfate, and the sodium sulfate addition amount is 2 wt% of the pyrrole monomer addition amount. Add the PS microsphere suspension prepared in step S3-3 to obtain a mixed reaction solution; S3-5: Dropwise add an ammonium persulfate solution with a mass concentration of 15% to the mixed reaction solution. The ammonium persulfate addition amount is 0.8 wt% of the pyrrole monomer. Then add the composite rubber particles prepared in step S3-2. The addition volume ratio of the composite rubber particles to the mixed reaction solution is 1:5, and react at 35 °C for 2.5 h; S3-6: After the reaction, filter to obtain modified rubber particles coated with a conductive polymer coating. Then use tetrahydrofuran to wash the modified rubber particles to remove the PS microspheres, and then dry to obtain composite rubber particles coated with a porous conductive polymer coating.

[0037] Example 6 A method for preparing sulfur autotrophic filter media from waste rubber tires is carried out according to the method in Example 1. The difference is that after the sulfur autotrophic agent is loaded on the activated rubber to obtain composite rubber particles in step S3, a porous conductive polymer coating is further formed on its surface. The specific method is as follows: S3-3: Ultrasonically disperse PS microspheres (particle size 0.1 - 0.2 μm) in 6 times the mass of water to obtain a PS microsphere suspension; S3-4: Mix pyrrole monomer and 3-aminopyrrole monomer in a mass ratio of 1:0.5 and dissolve them in water. The water addition amount is 2 times the mass of the pyrrole monomer addition amount to obtain a monomer solution. Then add sodium sulfate, and the sodium sulfate addition amount is 1 wt% of the pyrrole monomer addition amount. Add the PS microsphere suspension prepared in step S3-3 to obtain a mixed reaction solution; S3-5: Dropwise add an ammonium persulfate solution with a mass concentration of 15% to the mixed reaction solution. The ammonium persulfate addition amount is 0.5 wt% of the pyrrole monomer. Then add the composite rubber particles prepared in step S3-2. The addition volume ratio of the composite rubber particles to the mixed reaction solution is 1:4, and react at 30 °C for 3 h; S3-6. After the reaction, filter to obtain modified rubber particles coated with a conductive polymer coating. Then, use tetrahydrofuran to wash the modified rubber particles to remove the PS microspheres, and then dry to obtain composite rubber particles coated with a porous conductive polymer coating.

[0038] Example 7 A method for preparing a sulfur autotrophic filter material based on waste rubber tires is carried out according to the method in Example 1, except that after the sulfur autotrophic agent is loaded on the activated rubber to obtain composite rubber particles in step S3, a porous conductive polymer coating is further formed on its surface. The specific method is as follows: S3-3. Ultrasonically disperse PS microspheres (with a particle size of 0.1 - 0.2 μm) in 8 times the mass of water to obtain a PS microsphere suspension. S3-4. Mix pyrrole monomer and 1-aminopyrrole monomer according to a mass ratio of 1:0.6, dissolve them in water, and the water addition amount is 3 times the mass of the pyrrole monomer addition amount to obtain a monomer solution. Then, add sodium sulfate, and the sodium sulfate addition amount is 3 wt% of the pyrrole monomer addition amount. Add the PS microsphere suspension prepared in step S3-3 to obtain a mixed reaction solution. S3-5. Dropwise add an ammonium persulfate solution with a mass concentration of 20% to the mixed reaction solution, and the ammonium persulfate addition amount is 1 wt% of the pyrrole monomer. Then, add the composite rubber particles prepared in step S3-2, and the addition volume ratio of the composite rubber particles to the mixed reaction solution is 1:6. React at 40 °C for 2 h. S3-6. After the reaction, filter to obtain modified rubber particles coated with a conductive polymer coating. Then, use tetrahydrofuran to wash the modified rubber particles to remove the PS microspheres, and then dry to obtain composite rubber particles coated with a porous conductive polymer coating.

[0039] Example 8 A method for preparing a sulfur autotrophic filter material based on waste rubber tires is carried out according to the method in Example 5, except that in step S3-4, the 1-aminopyrrole monomer is replaced with an equal amount of pyrrole monomer.

[0040] Example 9 A method for preparing a sulfur autotrophic filter material based on waste rubber tires is carried out according to the method in Example 1, except that when the composite rubber particles and the binder are mixed in step S4, Fenton iron sludge and azodicarbonamide are also added. The addition amount of Fenton iron sludge (with an iron content of 8%) is 5 wt% of the addition amount of the composite rubber particles, and the addition amount of azodicarbonamide is 2 wt% of the addition amount of the composite rubber particles.

[0041] Example 10 A method for preparing sulfur autotrophic filter media based on rubber tire waste, which is carried out according to the method in Example 1. The difference is that when the composite rubber particles are mixed with the binder in step S4, Fenton iron mud and azodicarbonamide are also added. The addition amount of Fenton iron mud is 3wt% of the addition amount of composite rubber particles, and the addition amount of azodicarbonamide is 1wt% of the addition amount of composite rubber particles.

[0042] Example 11 A method for preparing sulfur autotrophic filter media based on rubber tire waste, which is carried out according to the method in Example 1. The difference is that when the composite rubber particles are mixed with the binder in step S4, Fenton iron mud and azodicarbonamide are also added. The addition amount of Fenton iron mud is 8wt% of the addition amount of composite rubber particles, and the addition amount of azodicarbonamide is 3wt% of the addition amount of composite rubber particles.

[0043] Comparative Example 1 A method for preparing sulfur autotrophic filter media based on rubber tire waste, which is carried out according to the method in Example 1. The difference is that the operation of step S2 is not carried out.

[0044] Comparative Example 2 A method for preparing sulfur autotrophic filter media based on rubber tire waste, which is carried out according to the method in Example 1. The difference is that after being washed with sodium hydroxide in step S2, it is not impregnated with dilute sulfuric acid.

[0045] Performance detection The sulfur autotrophic filter media prepared in the examples and comparative examples of the present application are placed on the filter plate to form a filter layer, and then the simulated sulfur-containing wastewater is allowed to enter the filter tank for treatment for 1 h and then flow out. The removal rates of sulfide and total nitrogen in the wastewater by the sulfur autotrophic filter media are statistically counted, and the statistical results are shown in Table 1 below. The removal rates of sulfide and total nitrogen after 20 cycles are also statistically counted, and the statistical results are shown in Table 2. Among them, the concentration of sodium sulfide in the simulated sulfur-containing wastewater is 200 mg / L, the concentration of ammonium chloride is 480 mg / L, the content of potassium nitrate is 250 mg / L, the content of ferrous sulfate is 80 mg / L, and the content of disodium hydrogen phosphate is 30 mg / L.

[0046] Table 1: Desulfurization and denitrification effects for the first time Table 2: Desulfurization and denitrification effects after 20 cycles Referring to the test results in Table 1 and Table 2 above, the sulfur autotrophic filter media prepared in the embodiments of the present application have good desulfurization and denitrification performance, and still have good desulfurization and denitrification performance after multiple cycles, with a long service life. Referring to the test results of Example 1 and Example 4, by impregnating and treating the activated rubber under ultrasonic conditions, the loading efficiency of the sulfur autotrophic agent is improved. At the same time, composite rubber particles with different particle sizes are mixed to enhance the mechanical strength and stability of the filter media balls. The sulfur autotrophic filter media prepared in Example 4 have better water treatment results. Combining the test results of Examples 5-7, after loading the sulfur autotrophic agent on the activated rubber, a porous conductive polymer coating is also coated on its surface. On the one hand, it helps to improve its electrochemical reaction and the water treatment effect. At the same time, the formation of the coating also helps to provide physical barrier protection for the sulfur autotrophic agent to achieve slow release. It also has excellent treatment effects after multiple cycles, improving the service life of the filter media. Combining the test results in Example 8 again, when only pyrrole monomer is added to prepare polypyrrole conductive polymer during the coating of the porous conductive polymer coating, the lack of additional adhesion provided by the amino functional group results in a reduction in its treatment effect compared to when pyrrole monomer and aminopyrrole monomer are compounded in Example 1. Especially after multiple cycles, its treatment ability decreases significantly. Combining the test results of Examples 9-11 again, when Fenton iron mud and azodicarbonamide are added during the molding of the composite rubber particles and the binder, its water treatment effect is also improved compared to Example 1, which is related to the addition of the above substances to the establishment of conductivity and porous structure.

[0047] Referring to the test results of Example 1 and Comparative Example 1 again, when the sulfur autotrophic agent is directly loaded on the waste rubber tire, there are insufficient surface active sites, resulting in a significant reduction in its water treatment effect, especially the poor water treatment effect after multiple cycles of use. Combining Comparative Example 2, when the waste rubber tire is only alkali-washed and not impregnated and activated with dilute sulfuric acid, due to the lack of the process of introducing oxygen-containing functional groups by sulfuric acid, its water treatment effect is poor.

[0048] This specific embodiment is only an explanation of the present application and does not limit the present application. Those skilled in the art can make modifications without creative contributions to this embodiment after reading this specification, 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 media from rubber tire waste, characterized in that, It includes the following steps: S1. Crush and screen waste rubber tires to obtain rubber particle waste. S2. Alkaline wash and then acid wash the rubber waste to obtain activated rubber. S3. Load a sulfur autotroph containing a sulfur source on the activated rubber and dry to obtain composite rubber particles. S4. Mix the composite rubber particles with a binder and press to form filter media balls. S5. Inoculate sulfur-oxidizing bacteria on the filter media balls and activate to obtain sulfur autotrophic filter media.

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

3. A method for preparing sulfur autotrophic filter media from rubber tire waste according to claim 1, characterized in that: The sulfur autotroph 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, sulfides such as sodium sulfide or sodium thiosulfate, and the nutrient is selected from one or more of phosphates and nitrogen sources.

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

5. A method for preparing sulfur autotrophic filter media based on waste rubber tires according to claim 1, characterized in that: In step S3, the sulfur autotroph includes elemental sulfur powder and potassium dihydrogen phosphate in a mass ratio of 1:(0.8-1.2). The sulfur autotroph is loaded on the activated rubber by impregnation. The specific operation is as follows: S3-1. Dissolve potassium dihydrogen phosphate in water, then add elemental sulfur powder and stir to obtain a sulfur autotroph impregnation solution. S3-2. Immerse the activated rubber in the sulfur autotroph impregnation solution for impregnation treatment, and then dry to obtain composite rubber particles.

6. A method for preparing sulfur autotrophic filter media from 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. A method for preparing sulfur autotrophic filter media from waste rubber tires according to claim 5, characterized in that: After obtaining the composite rubber particles in step S3, a porous conductive polymer coating is also formed on its surface. The specific method is as follows: S3-3. Ultrasonically disperse PS microspheres in water to obtain a PS microsphere suspension. S3-4. Dissolve pyrrole monomer and aminopyrrole monomer in water to obtain a monomer solution, then add sodium sulfate, and then add the PS microsphere suspension obtained in step S3-3 to obtain a mixed reaction solution. S3-5. Dropwise add an initiator solution to the mixed reaction solution, then add the composite rubber particles, and react at 30-40 °C for 2-3 h. S3-6. After the reaction, filter to obtain modified rubber particles coated with a conductive polymer coating, then wash the modified rubber particles with tetrahydrofuran to remove the PS microspheres, and then dry to obtain composite rubber particles coated with a porous conductive polymer coating.

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

9. A method for preparing sulfur autotrophic filter media from 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 particle sizes of 5-7 mm, 2-4 mm, and 0.5-1 mm in a mass ratio of (3-4):(5-6):

1.

10. A sulfur autotrophic filter material prepared by the method according to any one of claims 1-9.

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