Novel magnetic pyrite filler and application thereof in nitrogen and phosphorus removal of sewage

Abstract

The invention belongs to the field of nitrogen and phosphorus removal of sewage, and particularly relates to a novel magnetic pyrite filler and application thereof in nitrogen and phosphorus removal of sewage. Comprising the following components in parts by mass: 15-25 parts of pyrite powder, 12-15 parts of modified powder, 1-3 parts of calcium sulfide, 5-8 parts of sodium lignin sulfonate, 100-120 parts of deionized water and 150-200 parts of mixed bacterial liquid. Comprising the following steps: mixing pyrite powder with modified powder and calcium sulfide, stirring, adding sodium lignin sulfonate and deionized water, stirring, granulating, drying, heating to 350-400 DEG C, and keeping the temperature for 1-3 hours to prepare a mixed filler; the mixed filler is soaked in the mixed bacterial liquid, shaking culture, filtering and drying are conducted, and the novel magnetic pyrite filler is prepared; the prepared novel magnetic pyrite filler has excellent mechanical stability and efficient nitrogen and phosphorus removal efficiency, and efficient removal of nitrogen and phosphorus pollutants in sewage is achieved through the synergistic effect of physical adsorption and biodegradation.

Description

Technical Field

[0001] The present invention belongs to the field of sewage denitrification and phosphorus removal, and particularly relates to a novel magnetic pyrite filler and its application in sewage denitrification and phosphorus removal. Background Art

[0002] With the acceleration of the urbanization process and the sharp increase in industrial wastewater emissions, water eutrophication has become a global environmental issue of concern. In sewage denitrification and phosphorus removal technologies, the biological filler method has become one of the core processes for municipal sewage treatment plants and the treatment of high-concentration industrial wastewater due to its combined treatment efficiency and economy. The current mainstream biological denitrification and phosphorus removal technologies rely on activated sludge or traditional fillers, but there are problems such as low biofilm attachment efficiency, poor synergy of functional bacteria groups, and weak shock load resistance. Although the physicochemical method can quickly remove pollutants, it has high chemical consumption and is prone to secondary pollution.

[0003] Magnetic pyrite, as a natural sulfur-containing iron mineral, has semiconductor properties and redox activity, and theoretically can provide electrons or trace elements for microbial metabolism. However, single magnetic pyrite has defects such as a single pore structure, insufficient biocompatibility, and low electron transfer efficiency, which limit its application in sewage purification. Developing a novel filler with a high specific surface area, electrochemical activity, and microbial affinity is an important direction to improve the efficiency of sewage denitrification and phosphorus removal. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a novel magnetic pyrite filler and its application in sewage denitrification and phosphorus removal.

[0005] The present invention provides a novel magnetic pyrite filler, which comprises the following components in parts by mass: 15 - 25 parts of pyrite powder, 12 - 15 parts of modified powder, 1 - 3 parts of calcium sulfide, 5 - 8 parts of sodium lignosulfonate, 100 - 120 parts of deionized water, and 150 - 200 parts of mixed bacterial solution.

[0006] Preferably, the modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, stir and then crush, sieve, add polyhydroxyalkanoate solution and modified carbon nanotubes, stir, granulate, dry, heat to 700 - 800 °C, and keep warm for 2 - 3 h to obtain the modified powder.

[0007] Preferably, it comprises the following components in parts by mass: 10 - 15 parts of coconut shell activated carbon, 4 - 6 parts of eggshells, 30 - 40 parts of polyhydroxyalkanoate solution, and 5 - 8 parts of modified carbon nanotubes.

[0008] Preferably, the modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, disperse them by ultrasonic treatment, add manganese chloride, disperse again, then add carbon nanotubes and cetyltrimethylammonium bromide, stir, add ammonium nitrate, adjust the pH, heat and stir, let it stand for aging, centrifuge, collect the precipitate, wash it 3 times with ethanol, dry it, and then calcine the precipitate under nitrogen, cool it with the furnace, grind it and sieve it to obtain modified carbon nanotubes.

[0009] Preferably, it includes the following components in parts by mass: 1 - 2 parts of ferric chloride, 2 - 4 parts of ferrous chloride, 3 - 4 parts of manganese chloride, 12 - 16 parts of carbon nanotubes, 0.05 - 0.1 part of cetyltrimethylammonium bromide, 0.4 - 0.6 part of ammonium nitrate, and 60 - 70 parts of deionized water.

[0010] A preparation method of a novel magnetic pyrite filler includes the following steps: S1. Weigh the raw materials in the said parts by mass, mix pyrite powder with modified powder and calcium sulfide, stir, add sodium lignosulfonate and deionized water, stir, granulate, dry, heat up to 350 - 400 °C, and keep it warm for 1 - 3 h to obtain a mixed filler. S2. Immerse the mixed filler in the mixed bacterial solution, oscillate and culture for 48 - 60 h, filter, and dry to obtain the novel magnetic pyrite filler.

[0011] Preferably, in the step S2, the mixed bacterial solution is prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes, Stenotrophomonas maltophilia, and alkaline phosphatase, adjust the pH, control the temperature at 28 - 32 °C, and stir to obtain the mixed bacterial solution.

[0012] Preferably, it includes the following components in parts by mass: 3 - 5 parts of agar, 1 - 2 parts of glucose, 0.5 - 0.8 part of Pseudomonas alcaligenes, 1 - 2 parts of Stenotrophomonas maltophilia, 0.1 - 0.2 part of alkaline phosphatase, and 80 - 100 parts of deionized water.

[0013] The present invention also provides an application of the novel magnetic pyrite filler in sewage denitrification and phosphorus removal.

[0014] The present invention has the following beneficial effects: The present invention reacts ferric chloride, ferrous chloride and manganese chloride with carbon nanotubes, and then through calcination treatment, modified carbon nanotubes are successfully prepared. It has a high specific surface area and can adsorb nitrogen and phosphorus pollutants. A large number of active sites are formed by iron tetroxide and manganese elements on its surface, which can participate in the redox reactions of nitrogen and phosphorus and accelerate the reaction process. The carbon nanotubes themselves have good electron conduction properties, enabling rapid electron transfer inside the material, providing an electron channel for the redox reaction and increasing the reaction rate. The modified carbon nanotubes form a three-dimensional intertwined network structure with other raw materials, enhancing the overall structural stability of the filler, preventing the material from breaking and pulverizing during use, and at the same time optimizing the pore structure of the filler, ensuring efficient mass transfer of pollutants and ensuring the stable treatment performance of the material during long-term operation.

[0015] Coconut shell activated carbon and eggshells are mixed, crushed, and subjected to composite calcination with polyhydroxyalkanoate and modified carbon nanotubes to prepare a modified powder with multi-dimensional synergistic effects; among them, coconut shell activated carbon has a rich pore structure and a high specific surface area, and can efficiently enrich nitrogen and phosphorus pollutants through a physical adsorption mechanism. The iron tetroxide and manganese-based active components loaded on the surface of the modified carbon nanotubes can specifically react with nitrogen and phosphorus substances through chemical adsorption and coordination complexation, and stably fix them on the material surface. The iron element in pyrite powder can also form insoluble iron phosphate salt with phosphorus, thereby realizing the chemical fixation of phosphorus element and constructing an efficient pollutant interception system; the iron tetroxide / manganese redox system on the surface of the modified carbon nanotubes forms a functional coupling with the high conductivity of the carbon nanotubes. During the denitrification and phosphorus removal process, this system can rapidly transfer electrons, significantly reduce the reaction activation energy, and accelerate the nitrogen and phosphorus conversion reaction process. Polyhydroxyalkanoate, as a biodegradable polymer carbon source, can induce the resuscitation and growth of microorganisms with denitrification and phosphorus removal functions under trace moisture or appropriate environmental stimuli. After these microorganisms form a biofilm on the material surface, the enzymes produced by the microbial metabolic activities can catalyze the nitrogen and phosphorus conversion reactions, while the adsorption and catalytic characteristics of the material provide a stable nutrient source and reaction site for the microorganisms, generating a synergistic effect, and constructing a multi-level synergistic denitrification and phosphorus removal system under anhydrous or low moisture conditions, significantly improving the treatment efficiency and stability.

[0016] After thoroughly mixing and stirring pyrite powder, modified powder, and calcium sulfide, sodium lignosulfonate and deionized water are added and stirring continues. Subsequently, granulation and drying treatments are carried out, followed by high-temperature calcination to obtain a mixed filler. This mixed filler further reacts with a mixed bacterial solution to finally obtain a novel magnetic pyrite filler; during the shaking culture stage, Pseudomonas alcaligenes, Stenotrophomonas maltophilia, and alkaline phosphatase in the mixed bacterial solution will gradually attach to the surface of the filler, and then form a biofilm with a rich structure. This biofilm has a large specific surface area, which not only creates sufficient living space for microorganisms but also constructs an efficient interface for contact with pollutants in sewage, enabling more efficient capture and degradation of various pollutants in sewage. The biofilm firmly fixes the microorganisms on the filler, effectively avoiding the problem of microorganism loss with the water flow, and significantly improving the retention rate and stability of microorganisms in the sewage treatment system. Manganese ions and magnetite loaded on the surface of carbon nanotubes have an important impact on the physicochemical properties of the filler surface, changing the surface charge distribution and optimizing the pore structure. These changes create a more suitable living environment for microorganisms, greatly promoting the attachment and growth of microorganisms on the filler surface. At the same time, manganese ions and magnetite have strong redox activities and can undergo redox reactions with the metabolites of microorganisms, further accelerating the conversion process of pollutants and enhancing the comprehensive efficiency of the novel magnetic pyrite filler in sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram of an autotrophic denitrification device for testing the performance of the filler in the specific embodiment of the present invention. SPECIFIC EMBODIMENTS

[0018] Pyrite, purchased from Chenyang Mineral Products Co., Ltd., Lingshou County, was pulverized through a 300-mesh sieve before use; coconut shell activated carbon, purchased from Henan Weilan Environmental Protection Engineering Co., Ltd., 60 mesh; carbon nanotubes, purchased from Shanghai Gaibang Industrial Co., Ltd., product number: XT-CNTs, particle size 8 nm; Pseudomonas alcaligenes, purchased from the Hangzhou Branch of Wuhan Huizao Biotechnology Co., Ltd., product number: HZB115066, freeze-dried powder; Stenotrophomonas maltophilia, purchased from Ningbo Mingzhou Biotechnology Co., Ltd., product number: BMZ106708, freeze-dried powder; alkaline phosphatase, purchased from Hubei Jianchu Biopharmaceutical Co., Ltd., CAS number: 9001-78-9, active ingredient content: 99%; calcium sulfide, purchased from Wuhan Jiyesheng Chemical Co., Ltd., powder.

[0019] Example 1 A novel magnetic pyrite filler, comprising the following components in parts by mass: 15 parts of pyrite powder, 12 parts of modified powder, 1 part of calcium sulfide, 5 parts of sodium lignosulfonate, 100 parts of deionized water, and 150 parts of mixed bacterial solution.

[0020] Among them, the modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, mix at 200 rpm for 30 min, crush, pass through a 100-mesh sieve, add polyhydroxyalkanoate solution and modified carbon nanotubes, stir at 200 rpm for 20 min, granulate, control the particle size to be 2 mm, and dry at 40 °C for 12 h; heat to 400 °C at a rate of 5 °C / min, hold for 1 h, then heat to 700 °C at a rate of 2 °C / min, hold for 2 h, and cool with the furnace to obtain a mixed powder; among them, 10 parts of coconut shell activated carbon, 4 parts of eggshells, 30 parts of polyhydroxyalkanoate solution, and 5 parts of modified carbon nanotubes; disperse polyhydroxyalkanoate in acetone, stir at 100 rpm for 10 min to obtain a polyhydroxyalkanoate solution with a mass fraction of 15%.

[0021] Among them, the modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, ultrasonically disperse at 20 kHz for 5 min, add manganese chloride, disperse for 10 min, then add carbon nanotubes and cetyltrimethylammonium bromide, stir at 100 rpm for 10 min, add ammonium nitrate, adjust the pH to 9, heat to 60 °C, stir at 100 rpm for 3 h, stand and age at room temperature for 8 h, centrifuge at 4000 rpm for 10 min, collect the precipitate, wash with ethanol 3 times, dry at 60 °C for 6 h, then calcine the precipitate under nitrogen, heat to 280 °C at a rate of 5 °C / min, hold for 2 h, then heat to 400 °C at a rate of 2 °C / min, hold for 1 h, and cool with the furnace, grind and pass through a 100-mesh sieve to obtain modified carbon nanotubes; among them, 1 part of ferric chloride, 2 parts of ferrous chloride, 3 parts of manganese chloride, 12 parts of carbon nanotubes, 0.05 part of cetyltrimethylammonium bromide, 0.4 part of ammonium nitrate, and 60 parts of deionized water.

[0022] A preparation method of a novel magnetic pyrite filler, comprising the following steps: S1. Weigh the raw materials in the said parts by mass, mix pyrite powder with the modified powder and calcium sulfide, stir at 200 rpm for 15 min, add sodium lignosulfonate and deionized water, stir for 8 min, granulate, control the particle size to be 3 mm, dry at 60 °C for 4 h, heat to 350 °C at a rate of 5 °C / min, hold for 1 h, and cool with the furnace to obtain a mixed filler; S2. Immerse the mixed filler in the mixed bacterial solution, cultivate it by shaking at 150 rpm for 48 h, filter, and dry it at 25 °C for 24 h to obtain a novel magnetic pyrite filler; among them, the mixed bacterial solution is prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes, Stenotrophomonas maltophilia, and alkaline phosphatase, adjust the pH to 7.5, control the temperature at 28 °C, and stir at 100 rpm for 15 min; among them, 3 parts of agar, 1 part of glucose, 0.5 part of Pseudomonas alcaligenes, 1 part of Stenotrophomonas maltophilia, 0.1 part of alkaline phosphatase, and 80 parts of deionized water.

[0023] Application of a novel magnetic pyrite filler in sewage denitrification and phosphorus removal.

[0024] Example 2 A novel magnetic pyrite filler, comprising the following components in parts by mass: 25 parts of pyrite powder, 15 parts of modified powder, 3 parts of calcium sulfide, 8 parts of sodium lignosulfonate, 120 parts of deionized water, and 200 parts of mixed bacterial solution.

[0025] Among them, the modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, mix at 300 rpm for 40 min, crush, pass through a 150-mesh sieve, add polyhydroxyalkanoate solution and modified carbon nanotubes, stir at 300 rpm for 30 min, granulate, control the particle size to be 4 mm, and dry at 50 °C for 24 h; heat it to 500 °C at a rate of 8 °C / min, hold for 2 h, then heat it to 800 °C at a rate of 3 °C / min, hold for 3 h, and cool with the furnace to obtain a mixed powder; among them, 15 parts of coconut shell activated carbon, 6 parts of eggshells, 40 parts of polyhydroxyalkanoate solution, and 8 parts of modified carbon nanotubes; Disperse polyhydroxyalkanoate in acetone and stir at 150 rpm for 20 min to obtain a polyhydroxyalkanoate solution with a mass fraction of 15%.

[0026] Among them, the modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, ultrasonically disperse for 8 min at 30 kHz, add manganese chloride, disperse for 15 min, then add carbon nanotubes and cetyltrimethylammonium bromide, stir at 150 rpm for 15 min, add ammonium nitrate, adjust the pH to 11, heat to 70 °C, stir at 200 rpm for 4 h, stand and age at room temperature for 12 h, centrifuge at 5000 rpm for 15 min, collect the precipitate, wash it 3 times with ethanol, dry at 80 °C for 8 h, and then calcine the precipitate under nitrogen, heat it to 350 °C at a rate of 8 °C / min, hold for 3 h, then heat it to 450 °C at a rate of 4 °C / min, hold for 2 h, cool with the furnace, grind it through a 150-mesh sieve to obtain modified carbon nanotubes; among them, 2 parts of ferric chloride, 4 parts of ferrous chloride, 4 parts of manganese chloride, 16 parts of carbon nanotubes, 0.1 part of cetyltrimethylammonium bromide, 0.6 part of ammonium nitrate, and 70 parts of deionized water.

[0027] A preparation method of a novel magnetic pyrite filler, comprising the following steps: S1. Weigh the raw materials in the said parts by mass, mix pyrite powder with modified powder and calcium sulfide, stir at 300 rpm for 20 min, add sodium lignosulfonate and deionized water, stir for 15 min, granulate, control the particle size to be 4 mm, dry at 70 °C for 6 h, heat to 400 °C at a rate of 7 °C / min, hold for 3 h, cool with the furnace to obtain a mixed filler; S2. Immerse the mixed filler in the mixed bacterial solution, oscillate and culture at 200 rpm for 60 h, filter, dry at 30 °C for 36 h to obtain the novel magnetic pyrite filler; among them, the mixed bacterial solution is prepared by the following method: mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes, Stenotrophomonas maltophilia and alkaline phosphatase, adjust the pH to 7.5, control the temperature at 32 °C, stir at 200 rpm for 20 min to obtain; among them, 5 parts of agar, 2 parts of glucose, 0.8 part of Pseudomonas alcaligenes, 2 parts of Stenotrophomonas maltophilia, 0.2 part of alkaline phosphatase, and 100 parts of deionized water.

[0028] An application of a novel magnetic pyrite filler in sewage denitrification and phosphorus removal.

[0029] Example 3 A novel magnetic pyrite filler, comprising the following components in parts by mass: 20 parts of pyrite powder, 14 parts of modified powder, 2 parts of calcium sulfide, 6 parts of sodium lignosulfonate, 110 parts of deionized water, and 180 parts of mixed bacterial solution.

[0030] Among them, the modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, mix at 260 rpm for 35 min, crush, sieve through a 130-mesh sieve, add polyhydroxyalkanoate solution and modified carbon nanotubes, stir at 260 rpm for 25 min, granulate, control the particle size to be 3 mm, and dry at 45 °C for 18 h; heat to 450 °C at a rate of 6 °C / min, hold for 1.5 h, then heat to 750 °C at a rate of 3 °C / min, hold for 2.5 h, and cool with the furnace to obtain a mixed powder; among them, 12 parts of coconut shell activated carbon, 5 parts of eggshells, 35 parts of polyhydroxyalkanoate solution, and 7 parts of modified carbon nanotubes; disperse polyhydroxyalkanoate in acetone, stir at 120 rpm for 15 min to obtain a polyhydroxyalkanoate solution with a mass fraction of 15%.

[0031] Among them, the modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, ultrasonically disperse at 25 kHz for 7 min, add manganese chloride, disperse for 13 min, then add carbon nanotubes and cetyltrimethylammonium bromide, stir at 130 rpm for 12 min, add ammonium nitrate, adjust the pH to 10, heat to 65 °C, stir at 150 rpm for 3.5 h, stand and age at room temperature for 10 h, centrifuge at 4500 rpm for 13 min, collect the precipitate, wash with ethanol 3 times, dry at 70 °C for 7 h, then calcine the precipitate under nitrogen, heat to 330 °C at a rate of 7 °C / min, hold for 2.5 h, then heat to 430 °C at a rate of 3 °C / min, hold for 1.5 h, and cool with the furnace, grind and sieve through a 130-mesh sieve to obtain modified carbon nanotubes; among them, 1.5 parts of ferric chloride, 3 parts of ferrous chloride, 3.5 parts of manganese chloride, 14 parts of carbon nanotubes, 0.08 part of cetyltrimethylammonium bromide, 0.5 part of ammonium nitrate, and 65 parts of deionized water.

[0032] A preparation method of a novel magnetic pyrite filler, comprising the following steps: S1. Weigh the raw materials in the said parts by mass, mix pyrite powder with modified powder and calcium sulfide, stir at 260 rpm for 18 min, add sodium lignosulfonate and deionized water, stir for 13 min, granulate, control the particle size to be 3.5 mm, dry at 65 °C for 5 h, heat to 380 °C at a rate of 6 °C / min, hold for 2 h, and cool with the furnace to obtain a mixed filler; S2. Immerse the mixed filler in the mixed bacterial solution, shake and culture at 180 rpm for 54 h, filter, and dry at 28 °C for 30 h to obtain the novel magnetic pyrite filler; among them, the mixed bacterial solution is prepared by the following method: mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes, Stenotrophomonas maltophilia, and alkaline phosphatase, adjust the pH to 7.5, control the temperature at 30 °C, and stir at 150 rpm for 18 min; among them, there are 4 parts of agar, 1.5 parts of glucose, 0.7 part of Pseudomonas alcaligenes, 1.5 parts of Stenotrophomonas maltophilia, 0.2 part of alkaline phosphatase, and 90 parts of deionized water.

[0033] Application of a novel magnetic pyrite filler in sewage denitrification and phosphorus removal.

[0034] Comparative Example 1 Comparative Example 1 is the same as Example 1, the only difference is that the preparation method of the modified powder is different, specifically as follows: The modified powder is prepared by the following method: Crush the eggshells, pass through a 100-mesh sieve, add the polyhydroxyalkanoate solution and modified carbon nanotubes, stir at 200 rpm for 20 min, granulate, control the particle size to be 2 mm, and dry at 40 °C for 12 h; heat to 400 °C at a rate of 5 °C / min, hold for 1 h, then heat to 700 °C at a rate of 2 °C / min, hold for 2 h, and cool with the furnace to obtain the mixed powder; among them, there are 14 parts of eggshells, 30 parts of polyhydroxyalkanoate solution, and 5 parts of modified carbon nanotubes; disperse the polyhydroxyalkanoate in acetone and stir at 100 rpm for 10 min to obtain the polyhydroxyalkanoate solution with a mass fraction of 15%.

[0035] Comparative Example 2 Comparative Example 2 is the same as Example 1, the only difference is that the preparation method of the modified powder is different, specifically as follows: The modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, mix at 200 rpm for 30 min, crush, pass through a 100-mesh sieve, add modified carbon nanotubes and deionized water, stir at 200 rpm for 20 min, granulate, control the particle size to be 2 mm, and dry at 40 °C for 12 h; heat to 400 °C at a rate of 5 °C / min, hold for 1 h, then heat to 700 °C at a rate of 2 °C / min, hold for 2 h, and cool with the furnace to obtain the mixed powder; among them, there are 10 parts of coconut shell activated carbon, 4 parts of eggshells, 30 parts of deionized water, and 5 parts of modified carbon nanotubes.

[0036] Comparative Example 3 Comparative Example 3 is the same as Example 1, the only difference is that the preparation method of the modified carbon nanotubes is different, specifically as follows: The modified carbon nanotubes are prepared by the following method: Add manganese chloride to deionized water, ultrasonically disperse it at 20 kHz for 5 min, add carbon nanotubes and cetyltrimethylammonium bromide, stir at 100 rpm for 10 min, add ammonium nitrate, adjust the pH to 9, heat to 60 °C, stir at 100 rpm for 3 h, let it stand and age at room temperature for 8 h, centrifuge at 4000 rpm for 10 min, collect the precipitate, wash it with ethanol three times, dry it at 60 °C for 6 h, and then calcine the precipitate under nitrogen. Heat it to 280 °C at a rate of 5 °C / min, hold for 2 h, then heat it to 400 °C at a rate of 2 °C / min, hold for 1 h, cool it with the furnace, grind it through a 100-mesh sieve to obtain modified carbon nanotubes; among them, 6 parts of manganese chloride, 12 parts of carbon nanotubes, 0.05 part of cetyltrimethylammonium bromide, 0.4 part of ammonium nitrate, and 60 parts of deionized water.

[0037] Comparative Example 4 Comparative Example 4 is the same as Example 1, the only difference being that the preparation method of the modified carbon nanotubes is different, specifically as follows: The modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, ultrasonically disperse it at 20 kHz for 5 min, add carbon nanotubes and cetyltrimethylammonium bromide, stir at 100 rpm for 10 min, add ammonium nitrate, adjust the pH to 9, heat to 60 °C, stir at 100 rpm for 3 h, let it stand and age at room temperature for 8 h, centrifuge at 4000 rpm for 10 min, collect the precipitate, wash it with ethanol three times, dry it at 60 °C for 6 h, and then calcine the precipitate under nitrogen. Heat it to 280 °C at a rate of 5 °C / min, hold for 2 h, then heat it to 400 °C at a rate of 2 °C / min, hold for 1 h, cool it with the furnace, grind it through a 100-mesh sieve to obtain modified carbon nanotubes; among them, 2 parts of ferric chloride, 4 parts of ferrous chloride, 12 parts of carbon nanotubes, 0.05 part of cetyltrimethylammonium bromide, 0.4 part of ammonium nitrate, and 60 parts of deionized water.

[0038] Comparative Example 5 Comparative Example 5 is the same as Example 1, the only difference being that the preparation method of the mixed bacterial solution is different, specifically as follows: The mixed bacterial solution is prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes and alkaline phosphatase, adjust the pH to 7.5, control the temperature at 28 °C, stir at 100 rpm for 15 min to obtain it; among them, 3 parts of agar, 1 part of glucose, 1.5 parts of Pseudomonas alcaligenes, 0.1 part of alkaline phosphatase, and 80 parts of deionized water.

[0039] Comparative Example 6 Comparative Example 6 is the same as Example 1, except that the preparation method of the mixed bacterial solution is different. Specifically: The mixed bacterial solution was prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Stenotrophomonas maltophilia and alkaline phosphatase, adjust the pH to 7.5, control the temperature at 28°C, and stir at 100 rpm for 15 min to obtain; among them, 3 parts of agar, 1 part of glucose, 1.5 parts of Stenotrophomonas maltophilia, 0.1 part of alkaline phosphatase, and 80 parts of deionized water.

[0040] Comparative Example 7 Comparative Example 7 is the same as Example 1, except that the preparation method of the mixed bacterial solution is different. Specifically: The mixed bacterial solution was prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes and Stenotrophomonas maltophilia, adjust the pH to 7.5, control the temperature at 28°C, and stir at 100 rpm for 15 min to obtain; among them, 3 parts of agar, 1 part of glucose, 0.55 part of Pseudomonas alcaligenes, 1.05 parts of Stenotrophomonas maltophilia, and 80 parts of deionized water.

[0041] Performance test The following performance tests were carried out on the novel magnetic pyrite fillers prepared in Examples 1-3 and Comparative Examples 1-7: As Figure 1 shown in the device, two identical upflow anaerobic fixed-bed reactors with an inner diameter of 6.6 cm and a height of 40 cm were constructed, namely B1 and B2. At the same time, in order to reduce the filtration resistance of the system, porous plastic suspended fillers were filled, and the porous plastic suspended fillers and the novel magnetic pyrite fillers were filled in layers. The reactors were operated in a constant temperature water bath at 28°C for 10 d; test the removal efficiency of N in NO 3- and the removal efficiency of P in PO 3- ; in B1, the removal rate of N in NO 3- was 72.41%, and the removal rate of P in PO 3- was 84.45%; Compressive strength test: The compressive strength tests of each example and comparative example were carried out using a servo multi-functional high and low temperature control testing machine. Each sample was tested in three groups, and the average value was taken; The test results are shown in Table 1.

[0042] Table 1 Performance test results

[0043] The performance data of Example 1 and Comparative Examples 1-2 show that coconut shell activated carbon, with its developed pore structure and excellent specific surface area, can achieve efficient enrichment and interception of nitrogen and phosphorus-containing pollutants such as ammonia nitrogen, nitrate nitrogen, and phosphate through physical adsorption mechanisms such as van der Waals force, electrostatic interaction, and pore sieving, providing a material basis for subsequent biochemical conversion; polyhydroxyalkanoate, as a biodegradable polymer carbon source, can induce the colonization and proliferation of denitrifying and phosphorus-removing functional bacteria under trace moisture or environmental stimuli, promoting the formation of a biofilm with high metabolic activity on the material surface. This biofilm constructs a synergistic removal system through functional enzymes secreted by microorganisms. The combined introduction of coconut shell activated carbon and polyhydroxyalkanoate significantly improves the denitrification and phosphorus-removal efficiency of the filler under complex water quality conditions by enhancing the pollutant interception efficiency and activating the microbial metabolic pathway.

[0044] According to the test results of Example 1 and Comparative Examples 3-4, the iron oxide and manganese-based active components constructed on the surface of carbon nanotubes form a heterogeneous structure with redox activity, and the exposed Fe²⁺ / Fe³⁺, Mn²⁺ / Mn 4 ⁺ and other redox couples on its surface constitute rich catalytic active sites. These active sites significantly accelerate the redox reaction kinetics of nitrogen and phosphorus pollutants by reducing the reaction activation energy. In addition, the combination of the intrinsic high conductivity of carbon nanotubes and their one-dimensional nanostructure constructs an efficient electron transport channel inside the material, enabling the directional and rapid migration of electrons in the redox reaction. The synergistic effect of this electron conduction property and the catalytic function of surface active sites effectively improves the electron utilization efficiency and material conversion rate of nitrogen and phosphorus conversion reactions, thus significantly enhancing the denitrification and phosphorus-removal efficiency of the filler.

[0045] According to the test results of Example 1 and Comparative Examples 5-7, the mixed bacterial solution made of Pseudomonas alcaligenes, Stenotrophomonas maltophilia, and alkaline phosphatase will gradually attach to the surface of the filler during the shaking culture stage, and then form a biofilm with a rich structure. Through the multiple effects of microbial surface adsorption and biofilm pore interception, the capture efficiency of nitrogen and phosphorus pollutants and organic substrates in sewage is significantly enhanced. Combined with the catalytic action of the intracellular enzyme system of microorganisms, efficient degradation and conversion of various pollutants are achieved; alkaline phosphatase catalyzes the hydrolysis of organic phosphorus compounds to convert them into inorganic phosphorus forms that can be directly utilized by microorganisms. The inorganic phosphorus generated in this process can be taken up by Pseudomonas alcaligenes and Stenotrophomonas maltophilia through the active transport mechanism and synthesized into polyphosphate for storage under the action of intracellular polyphosphate kinase, thus significantly enhancing the phosphorus enrichment efficiency of the biofilm on the filler surface. In addition, through continuous catalytic effects, alkaline phosphatase effectively addresses the problem of fluctuating treatment efficiency caused by fluctuations in phosphorus forms in wastewater, especially achieving efficient targeted regulation of phosphorus in high-proportion organic phosphorus pollution scenarios.

[0046] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A novel pyrrhotite filler, characterized in that, Comprising the following components in parts by mass: Pyrite powder 15 - 25 parts, modified powder 12 - 15 parts, calcium sulfide 1 - 3 parts, sodium lignosulfonate 5 - 8 parts, deionized water 100 - 120 parts, mixed bacterial solution 150 - 200 parts.

2. The novel pyrrhotite filler according to claim 1, wherein The modified powder is prepared by the following method: Mix coconut shell activated carbon and eggshells, stir, crush, sieve, add polyhydroxyalkanoate solution and modified carbon nanotubes, stir, granulate, dry, heat to 700 - 800 °C, and keep warm for 2 - 3 h to obtain the modified powder.

3. A novel magnetic pyrite filler according to claim 2, characterized in that, Comprising the following components in parts by mass: coconut shell activated carbon 10 - 15 parts, eggshell 4 - 6 parts, polyhydroxyalkanoate solution 30 - 40 parts, modified carbon nanotubes 5 - 8 parts.

4. A novel magnetic pyrite filler according to claim 2, wherein, The modified carbon nanotubes are prepared by the following method: Add ferric chloride and ferrous chloride to deionized water, disperse ultrasonically, add manganese chloride, disperse, then add carbon nanotubes and cetyltrimethylammonium bromide, stir, add ammonium nitrate, adjust the pH, heat and stir, stand for aging, centrifuge, collect the precipitate, wash with ethanol 3 times, dry, then calcine the precipitate under nitrogen, cool with the furnace, grind and sieve to obtain the modified carbon nanotubes.

5. A novel pyrrhotite filler according to claim 4, wherein Comprising the following components in parts by mass: ferric chloride 1 - 2 parts, ferrous chloride 2 - 4 parts, manganese chloride 3 - 4 parts, carbon nanotubes 12 - 16 parts, cetyltrimethylammonium bromide 0.05 - 0.1 part, ammonium nitrate 0.4 - 0.6 part, deionized water 60 - 70 parts.

6. A method for preparing the novel pyrrhotite filler according to any one of claims 1-5, characterized in that, Including the following steps: S1. Weigh the raw materials in the said parts by mass, mix pyrite powder with the modified powder and calcium sulfide, stir, add sodium lignosulfonate and deionized water, stir, granulate, dry, heat up to 350 - 400 °C, and keep warm for 1 - 3 h to obtain the mixed filler. S2. Immerse the mixed filler in the mixed bacterial solution, shake and culture for 48 - 60 h, filter, and dry to obtain the novel magnetic pyrite filler.

7. The preparation method of a novel magnetic pyrite filler according to claim 6, characterized in that, In the said step S2, the mixed bacterial solution is prepared by the following method: Mix agar and deionized water, stir, add glucose, stir, then add Pseudomonas alcaligenes, Stenotrophomonas maltophilia and alkaline phosphatase, adjust the pH, control the temperature at 28 - 32 °C, and stir to obtain the mixed bacterial solution.

8. The preparation method of a novel pyrrhotite filler according to claim 7, characterized in that, Comprising the following components in parts by mass: agar 3 - 5 parts, glucose 1 - 2 parts, Pseudomonas alcaligenes 0.5 - 0.8 part, Stenotrophomonas maltophilia 1 - 2 parts, alkaline phosphatase 0.1 - 0.2 part, deionized water 80 - 100 parts.

9. Use of a novel magnetic pyrite filler according to any one of claims 1 - 5 in sewage denitrification and phosphorus removal.

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