Preparation method and application of self-activity denitrification and dephosphorization functional filler

Abstract

This invention discloses a preparation method and application of a self-activated denitrification and phosphorus removal functional filler, belonging to the fields of environmental protection and water treatment technology. The method involves foaming animal protein foaming agent and water to obtain foam, and then mixing cement, pyrite powder, high-alumina bauxite aggregate, modified adsorption fiber, foam stabilizer, and polycarboxylate superplasticizer with water to obtain a slurry. The foam and slurry are mixed, poured into a mold for curing, and then crushed to obtain the self-activated denitrification and phosphorus removal functional filler. The porous composite particles in the modified adsorption fiber exhibit good adsorption performance for nitrogen and phosphorus pollutants in water. Hydrolyzed polymaleic anhydride is introduced into the porous composite particles through a reaction. The numerous carboxyl groups in the polymaleic anhydride can form stable chelates with calcium and magnesium ions in the slurry. Combined with the steric hindrance effect provided by the hydrolyzed polymaleic anhydride polymer chain, this prevents the aggregation of calcium and magnesium ions, helping to avoid the agglomeration of insoluble calcium and magnesium salts on the surface of the porous composite particles, thus ensuring the adsorption effect of the porous composite particles.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and water treatment technology, specifically relating to the preparation method and application of a self-activating denitrification and phosphorus removal functional packing. Background Technology

[0002] Environmental water treatment is a water purification technology that combines physical, chemical, and biological methods. It was developed based on soft and semi-soft water treatment materials, combining the advantages of both. Its principle is mainly to remove pollutants from water, including organic matter, inorganic salts, and heavy metals, through specific physical, chemical, and biological processes, thereby significantly improving water quality.

[0003] River and lake purification systems are an important application area of ​​environmental water treatment, widely used in the treatment and restoration of urban rivers, lakes, reservoirs, and other water bodies. Physical purification technologies in environmental water treatment, such as filtration and sedimentation, can effectively remove solid particles and suspended matter from rivers and lakes; chemical purification technologies, such as oxidation and reduction, can transform harmful substances in rivers and lakes; and biological purification technologies utilize the metabolic activity of microorganisms to remove organic pollutants from the water.

[0004] Chinese patent CN110002806B discloses a lightweight slow-release denitrification and phosphorus removal material, its preparation method and application. It features slow-release electron donor denitrification and iron ion dephosphorization, and can be used as a packing material for fluidized beds and fixed beds in sewage treatment; a packing material for artificial wetlands; and an in-situ and ex-situ purification material for polluted water bodies. It has a good purification effect on pollutants in water, especially ammonia nitrogen and total phosphorus.

[0005] These water treatment fillers, similar to foamed concrete, typically contain porous adsorption particles with good adsorption properties. However, during the preparation process, calcium and magnesium ions from cement and other raw materials can form insoluble salts on the surface of the porous adsorption particles, leading to a decrease in their nitrogen and phosphorus removal efficiency. Summary of the Invention

[0006] One objective of this invention is to provide a method for preparing a self-activated denitrification and phosphorus removal functional packing, thereby solving the problem that the adsorbent material added to the denitrification and phosphorus removal functional packing is easily blocked by micropores; another objective is to provide a method for using the self-activated denitrification and phosphorus removal functional packing.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A method for preparing a self-activating denitrification and phosphorus removal functional filler includes the following steps:

[0009] Step 1: Add cement, pyrite powder, high-alumina bauxite aggregate, modified adsorbent fiber, foam stabilizer and polycarboxylate superplasticizer to the mixer and mix for 2-3 minutes at 120-200 r / min. Then add water to the mixer and continue mixing for 5-10 minutes to obtain the slurry.

[0010] Step 2: Add animal protein foaming agent and water to a foaming machine at a mass ratio of 1:30-50 and foam to obtain a density of 0.06-0.08 g / cm³. 3 foam;

[0011] Step 3: Add the foam and slurry to a mixer at a mass ratio of 1:4, and mix at 600-800 rpm for 3-5 minutes. Pour the mixture into a mold and cure at 20-25℃ for 3-5 days. Crush the mixture to obtain a density of 1.2-1.5 g / cm³. 3 Self-activating denitrification and phosphorus removal functional packing.

[0012] Furthermore, in step one, the ratio of cement, pyrite powder, high-alumina bauxite aggregate, modified adsorbent fiber, foam stabilizer, water-reducing agent and water is 20-40:15-30:15-30:10-20:0.05-0.15:0.1-0.3:6-12.

[0013] Furthermore, the maximum size of the self-activated denitrification and phosphorus removal functional packing is 2-5 cm.

[0014] Furthermore, the foam stabilizer is methylcellulose or hydroxypropyl methylcellulose ether.

[0015] Furthermore, the modified adsorption fibers are prepared through the following steps:

[0016] Step 1: Hydrolyzed polymaleic anhydride, 3-glycidoxypropyltrimethoxysilane, benzyltriethylamine chloride, and anhydrous toluene are added to a reaction vessel. Benzyltriethylamine chloride is used as a catalyst, and anhydrous toluene is used as a solvent. The reaction is carried out under nitrogen protection and at 117-120℃ for 6-8 hours to open the epoxy groups in 3-glycidoxypropyltrimethoxysilane. Then, the temperature is lowered to 60-65℃, and sodium hydroxide powder and calcium oxide powder are added to the reaction vessel to provide alkaline conditions and remove moisture from the reaction system. The reaction is carried out for 3-3.5 hours. The ring-opened groups of the raw material 3-glycidoxypropyltrimethoxysilane undergo a condensation reaction with the carboxyl groups on the hydrolyzed polymaleic anhydride. Diatomaceous earth is then added to the reaction vessel as a filter aid and adsorbent. The reaction is carried out for 0.5-1 hours, filtered, and the filtrate is distilled under reduced pressure to remove the solvent and unreacted monomers. The product is dried to obtain the modified silane.

[0017] Step 2: Mix activated carbon powder and β-type hydroxy iron oxide nanoparticles evenly, then transfer them to a reaction vessel. Add anhydrous toluene, anhydrous pyridine, and modified silane. Anhydrous pyridine acts as a catalyst. Under nitrogen protection and at 80-85℃, keep the mixture warm for 20-24 hours to graft the hydroxyl groups on the activated carbon powder and β-type hydroxy iron oxide nanoparticles onto the silicon-oxygen bonds on the modified silane, thus loading the β-type hydroxy iron oxide nanoparticles onto the activated carbon powder particles. Filter the mixture, wash the filter cake 3-5 times with anhydrous methanol, and vacuum dry to obtain porous composite particles.

[0018] Step 3: Add a 1.5-2 g / L aqueous solution of dopamine hydrochloride to the reactor. Adjust the pH to 8.5 with a 0.5-1 mol / L Tris-HCl buffer solution. Then add pre-etched basalt fibers and porous composite particles to the reactor. Stir for 20-24 h at 20-25℃ and 120-200 r / min. The dopamine hydrochloride reacts to form polydopamine. The polydopamine is dehydrated by reacting with amino groups and hydroxyl groups on the surface of the porous composite particles and pre-etched basalt fibers. The porous composite particles are then bonded to the surface of the pre-etched fibers. Filter the product and wash it with deionized water until the final washing solution is neutral. Vacuum dry to obtain the modified adsorption fiber.

[0019] Furthermore, the ratio of activated carbon powder, β-type hydroxy iron oxide nanopowder, anhydrous toluene, anhydrous pyridine, and modified silane is 1.5-2g: 1g: 80-100mL: 2-3mL: 12.5-15g.

[0020] Furthermore, the ratio of dopamine hydrochloride aqueous solution, pre-etched basalt fiber and porous composite particles is 80-100mL: 1-1.2g: 0.4-0.6g.

[0021] Furthermore, β-type iron hydroxyoxide nanopowder is prepared via the following steps:

[0022] Ferric chloride, polyvinylpyrrolidone, and deionized water were added to a reaction vessel and stirred at 200-500 r / min for 10-20 min. Then, stirring was continued at 85-90℃ for 150-180 min. The mixture was allowed to cool naturally, centrifuged, filtered, and the product was washed 3-5 times with anhydrous ethanol and deionized water, respectively. The product was then vacuum dried and pulverized to obtain β-type ferric hydroxide nanopowder.

[0023] Furthermore, the ratio of ferric chloride, polyvinylpyrrolidone, and deionized water is 3-5g: 2-3g: 200-250mL.

[0024] Furthermore, the pre-etched basalt fibers are prepared through the following steps:

[0025] Basalt fibers are transferred to a stirred tank, and a sulfuric acid solution with a mass fraction of 5-8% is added to the stirred tank to immerse the basalt fibers. The fibers are then ultrasonically dispersed for 40-60 minutes, filtered, and the treated basalt fibers are washed with deionized water until the final washing solution is neutral. The fibers are then dried to obtain pre-etched basalt fibers.

[0026] The self-activating denitrification and phosphorus removal functional packing prepared by the above method can be applied to water treatment packing.

[0027] The beneficial effects of this invention are:

[0028] The self-activating denitrification and phosphorus removal functional filler prepared by the method of this invention has a density of 1.2-1.5 g / cm³. 3 This lightweight material contains pyrite powder, which has a slow-release electron donor effect for denitrification and iron ion removal, and high-alumina bauxite aggregate, which has a water purification effect. The modified adsorption fiber not only has a good adsorption effect on pollutants, but also helps to increase the strength of the self-activated denitrification and phosphorus removal functional packing. While reducing the density and porosity of the functional packing, it prevents internal collapse of the functional packing, improves the uniformity of the density of the functional packing, and prevents blockage caused by internal collapse. It also helps microbial growth and reproduction and improves the aeration effect. This functional packing has a large porosity and a large specific surface area, making it suitable for wastewater treatment. It helps microbial biofilm formation and gas flow during aeration, improving the denitrification and phosphorus removal effect of river and lake purification systems.

[0029] In the modified adsorption fibers, β-type hydroxyl iron oxide nanoparticles exhibit strong adsorption capacity for phosphorus, while activated carbon powder demonstrates excellent adsorption performance, effectively removing organic pollutants and heavy metal ions from water. The combination of β-type hydroxyl iron oxide nanoparticles and activated carbon powder into porous composite particles further enhances the adsorption performance for nitrogen and phosphorus pollutants in water. Pre-etching of basalt fibers increases surface roughness and hydroxyl content, facilitating the bonding of porous composite particles to the pre-etched basalt fiber surface through reaction. This improves the uniformity of dispersion of the porous composite particles within the functional filler and reduces agglomeration.

[0030] Hydrolyzed polymaleic anhydride is introduced into porous composite particles through a reaction. The large number of carboxyl groups in the polymaleic anhydride can form stable chelates with calcium and magnesium ions in the slurry, preventing the formation of insoluble precipitates. Combined with the steric hindrance effect provided by the hydrolyzed polymaleic anhydride polymer chain, it prevents the aggregation of calcium and magnesium ions. In the preparation process of self-activated denitrification and phosphorus removal functional filler, it helps to avoid the aggregation of insoluble calcium and magnesium salts on the surface of porous composite particles, thereby ensuring the adsorption effect of porous composite particles. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a method for preparing a self-activating denitrification and phosphorus removal functional filler, including the following steps:

[0034] Step 1: Add 30 kg of hydrolyzed polymaleic anhydride, 25 kg of 3-glycidyl etheroxypropyltrimethoxysilane, 5 kg of benzyltriethylamine chloride, and 500 L of anhydrous toluene to a reaction vessel. Under nitrogen protection and at 117 °C, maintain the temperature for 6 h. Then, cool the temperature to 60 °C and add 1 kg of sodium hydroxide powder and 0.5 kg of calcium oxide powder to the reaction vessel. Maintain the temperature for 3 h. Then, add 15 kg of diatomaceous earth to the reaction vessel and maintain the temperature for 0.5 h. Filter the mixture and remove the solvent and unreacted monomers by vacuum distillation of the filtrate. Dry the product to obtain the modified silane.

[0035] Step 2: Add 30 kg of ferric chloride, 20 kg of polyvinylpyrrolidone and 2000 L of deionized water to the reaction vessel, stir at 200 r / min for 10 min, then continue stirring at 85 °C for 150 min, cool naturally, centrifuge, filter, wash the product three times with anhydrous ethanol and deionized water respectively, vacuum dry, pulverize, and obtain β-type ferric hydroxide nanopowder;

[0036] Mix 1.5 kg of activated carbon powder and 1 kg of β-type hydroxyl iron oxide nanoparticles evenly, then transfer them to a reaction vessel. Add 80 L of anhydrous toluene, 2 L of anhydrous pyridine and 12.5 kg of the modified silane from step one. Keep the mixture at 80 °C under nitrogen protection for 20 h. Filter the mixture, wash the filter cake three times with anhydrous methanol, and vacuum dry it to obtain porous composite particles.

[0037] Step 3: Transfer the basalt fiber to a mixing tank, add a 5% sulfuric acid solution to the mixing tank to immerse the basalt fiber, ultrasonically disperse for 40 minutes, filter, wash the treated basalt fiber with deionized water until the final washing solution is neutral, dry, and obtain pre-etched basalt fiber.

[0038] Add 160 L of a 1.5 g / L dopamine hydrochloride aqueous solution to the reactor, adjust the pH to 8.5 with a 0.5 mol / L Tris-HCl buffer solution, then add 2 kg of pre-etched basalt fiber and 0.8 kg of the porous composite particles from step two to the reactor. Stir for 20 h at 20 °C and 120 r / min, filter, wash the product with deionized water until the final wash solution is neutral, and vacuum dry to obtain the modified adsorption fiber.

[0039] Step 4: Add 1 kg of animal protein foaming agent and 30 kg of water to a foaming machine for foaming, resulting in a density of 0.06 g / cm³. 3 foam;

[0040] Add 2 kg of cement, 1.5 kg of pyrite powder, 1.5 kg of high-alumina bauxite aggregate, 1 kg of modified adsorbent fiber, 0.005 kg of methyl cellulose and 0.01 kg of polycarboxylate superplasticizer to a mixer and stir at 120 r / min for 2 min. Then add 0.6 kg of water to the mixer and continue stirring for 5 min to obtain the slurry.

[0041] Add 1 kg of foam and 4 kg of slurry to a mixer and mix at 600 r / min for 3 minutes. Pour the mixture into a mold and cure at 20℃ for 3 days. Crush the mixture to obtain a self-activated denitrification and dephosphorization filler with a size of 2-5 cm.

[0042] Example 2

[0043] This embodiment provides a method for preparing a self-activating denitrification and phosphorus removal functional filler, including the following steps:

[0044] Step 1: Add 35 kg of hydrolyzed polymaleic anhydride, 28 kg of 3-glycidyl etheroxypropyltrimethoxysilane, 5.5 kg of benzyltriethylamine chloride, and 500 L of anhydrous toluene to a reaction vessel. Under nitrogen protection and at 118 °C, maintain the temperature for 7 h. Then, cool the temperature to 62 °C and add 1.5 kg of sodium hydroxide powder and 0.8 kg of calcium oxide powder to the reaction vessel. Maintain the temperature for 3.2 h. Then, add 18 kg of diatomaceous earth to the reaction vessel and maintain the temperature for 0.8 h. Filter the mixture and remove the solvent and unreacted monomers by vacuum distillation of the filtrate. Dry the product to obtain the modified silane.

[0045] Step 2: Add 40 kg of ferric chloride, 25 kg of polyvinylpyrrolidone and 2300 L of deionized water to the reaction vessel, stir at 350 r / min for 15 min, then continue stirring at 88 °C for 160 min, cool naturally, centrifuge, filter, wash the product three times with anhydrous ethanol and deionized water respectively, vacuum dry, pulverize, and obtain β-type ferric hydroxide nanopowder;

[0046] 1.8 kg of activated carbon powder and 1 kg of β-type hydroxyl iron oxide nanoparticles were mixed evenly and then transferred to a reaction vessel. 90 L of anhydrous toluene, 2.5 L of anhydrous pyridine and 13.5 kg of the modified silane from step one were then added. The mixture was kept at 82 °C under nitrogen protection for 22 h. After filtration, the filter cake was washed four times with anhydrous methanol and dried under vacuum to obtain porous composite particles.

[0047] Step 3: Transfer the basalt fiber to a mixing tank, add a 6% sulfuric acid solution to the mixing tank to immerse the basalt fiber, ultrasonically disperse for 50 minutes, filter, wash the treated basalt fiber with deionized water until the final washing solution is neutral, and dry to obtain pre-etched basalt fiber.

[0048] Add 180 L of a 1.8 g / L dopamine hydrochloride aqueous solution to the reactor, adjust the pH to 8.5 with a 0.8 mol / L Tris-HCl buffer solution, then add 2.2 kg of pre-etched basalt fiber and 1 kg of the porous composite particles from step two to the reactor. Stir for 22 h at 22 °C and 160 r / min, filter, wash the product with deionized water until the final wash solution is neutral, and vacuum dry to obtain the modified adsorption fiber.

[0049] Step 4: Add 1 kg of animal protein foaming agent and 40 kg of water to a foaming machine for foaming, resulting in a density of 0.07 g / cm³. 3 foam;

[0050] Add 3 kg of cement, 2 kg of pyrite powder, 2.2 kg of high-alumina bauxite aggregate, 1.5 kg of modified adsorbent fiber, 0.01 kg of hydroxypropyl methylcellulose ether, and 0.02 kg of polycarboxylate superplasticizer to a mixer and stir at 160 r / min for 2.5 min. Then add 0.9 kg of water to the mixer and continue stirring for 8 min to obtain the slurry.

[0051] Add 1 kg of foam and 4 kg of slurry to a mixer and mix at 700 r / min for 4 minutes. Pour the mixture into a mold and cure at 23℃ for 4 days. Crush the mixture to obtain a self-activated denitrification and dephosphorization filler with a size of 2-5 cm.

[0052] Example 3

[0053] This embodiment provides a method for preparing a self-activating denitrification and phosphorus removal functional filler, including the following steps:

[0054] Step 1: Add 40 kg of hydrolyzed polymaleic anhydride, 30 kg of 3-glycidyl etheroxypropyltrimethoxysilane, 6 kg of benzyltriethylamine chloride, and 500 L of anhydrous toluene to a reaction vessel. Keep the reaction at 120 °C under nitrogen protection for 8 h. Then cool down to 65 °C, add 2 kg of sodium hydroxide powder and 1 kg of calcium oxide powder to the reaction vessel, keep the reaction at 3.5 h, then add 20 kg of diatomaceous earth to the reaction vessel and keep the reaction at 1 h. Filter, remove the solvent and unreacted monomers by vacuum distillation of the filtrate, and dry the product to obtain modified silane.

[0055] Step 2: Add 50 kg of ferric chloride, 30 kg of polyvinylpyrrolidone and 2500 L of deionized water to the reaction vessel, stir at 500 r / min for 20 min, then continue stirring at 90 °C for 180 min, cool naturally, centrifuge, filter, wash the product 5 times with anhydrous ethanol and deionized water respectively, vacuum dry, pulverize to obtain β-type ferric hydroxide nanopowder;

[0056] 2 kg of activated carbon powder and 1 kg of β-type hydroxyl iron oxide nanoparticles were mixed evenly and then transferred to a reaction vessel. 100 L of anhydrous toluene, 3 L of anhydrous pyridine and 15 kg of the modified silane from step one were then added. The mixture was kept at 85 °C under nitrogen protection for 24 h. After filtration, the filter cake was washed five times with anhydrous methanol and dried under vacuum to obtain porous composite particles.

[0057] Step 3: Transfer the basalt fiber to a mixing tank, add an 8% sulfuric acid solution to the mixing tank to immerse the basalt fiber, ultrasonically disperse for 60 minutes, filter, wash the treated basalt fiber with deionized water until the final washing solution is neutral, and dry to obtain pre-etched basalt fiber.

[0058] Add 200 L of a 2 g / L dopamine hydrochloride aqueous solution to the reactor, adjust the pH to 8.5 with a 1 mol / L Tris-HCl buffer solution, then add 2.4 kg of pre-etched basalt fiber and 1.2 kg of the porous composite particles from step two to the reactor. Stir for 24 h at 25 °C and 200 r / min, filter, wash the product with deionized water until the final wash solution is neutral, and vacuum dry to obtain the modified adsorption fiber.

[0059] Step 4: Add 1 kg of animal protein foaming agent and 50 kg of water to a foaming machine for foaming, resulting in a density of 0.08 g / cm³. 3 foam;

[0060] Add 4 kg of cement, 3 kg of pyrite powder, 3 kg of high-alumina bauxite aggregate, 2 kg of modified adsorbent fiber, 0.015 kg of hydroxypropyl methylcellulose ether and 0.03 kg of polycarboxylate superplasticizer to a mixer and stir at 200 r / min for 3 min. Then add 1.2 kg of water to the mixer and continue stirring for 10 min to obtain the slurry.

[0061] Add 1 kg of foam and 4 kg of slurry to a mixer and mix at 800 r / min for 5 min. Pour the mixture into a mold and cure at 25℃ for 5 days. Crush the mixture to obtain a self-activated denitrification and dephosphorization filler with a size of 2-5 cm.

[0062] Comparative Example 1: Based on Example 3, step two was performed without adding β-type hydroxyl iron oxide nanopowder, while the remaining steps remained unchanged, to prepare a self-activated denitrification and phosphorus removal functional filler.

[0063] Comparative Example 2: Based on Example 3, the modified silane in step two was replaced with 3-glycidyl etheroxypropyltrimethoxysilane, i.e., without hydrolysis of polymaleic anhydride modification, while the other steps remained unchanged, to prepare a self-activated denitrification and phosphorus removal functional filler.

[0064] Comparative Example 3: Based on Example 3, no modified adsorption fiber was added in step four, while the remaining steps remained unchanged, to prepare a self-activated denitrification and phosphorus removal functional packing.

[0065] In the examples and comparative examples, the cement was Conch brand silicate cement; hydrolyzed polymaleic anhydride was purchased from Hubei Xingyan New Material Technology Co., Ltd., with an effective ingredient content of 99%; 3-glycidyl etheroxypropyltrimethoxysilane was purchased from Qufu Yishun Chemical Co., Ltd., with an effective ingredient content of 98%; ferric chloride was purchased from Shandong Maofa Chemical Co., Ltd.; polyvinylpyrrolidone was purchased from Jiangsu Pules Biotechnology Co., Ltd.; activated carbon powder was purchased from Zhengzhou Yongkun Environmental Protection Technology Co., Ltd., 200 mesh; basalt fiber was purchased from Jiangxi Shuobang New Material Technology Co., Ltd., 8±2 mm; dopamine hydrochloride aqueous solution was prepared from dopamine hydrochloride purchased from Jiangxi Muzan Biotechnology Co., Ltd.; animal protein foaming agent was purchased from Chiping Zetai Building Materials Co., Ltd.; pyrite powder was purchased from Tongling Fusu Mineral Products Industry and Trade Co., Ltd.; high-alumina bauxite aggregate was purchased from Zhengzhou Kanghui Refractory Materials Co., Ltd., 60 mesh; and polycarboxylate superplasticizer was purchased from Shandong Hongquan Chemical Technology Co., Ltd.

[0066] The self-activated nitrogen and phosphorus removal functional packing materials used in Examples 1-3 and Comparative Examples 1-3 were applied and their performance tested. Cubic specimens with dimensions of 100mm × 100mm × 100mm were prepared according to the method in JG / T 266-2011, and the dry density and compressive strength of different specimens were tested. The porosity of different specimens was tested according to CJ / T 299-2008. Different functional packing materials were packed into filter columns with a diameter of 12cm and a height of 100cm, with a packing height of 70cm. Then, self-made wastewater with an ammonia nitrogen concentration of 15mg / L and a total phosphorus concentration of 0.8mg / L was introduced. The residence time of the self-made wastewater in the filter column was 30min. The ammonia nitrogen concentration and total phosphorus concentration in the treated wastewater were checked. The results are shown in Table 1.

[0067] Table 1

[0068] <![CDATA[Dry density (g / cm 3 )]]> 0.54 0.56 0.56 0.55 0.52 0.73 Compressive strength (MPa) 0.98 0.96 1.01 0.86 0.83 0.68 Porosity (%) 76.23 77.37 76.15 76.22 74.85 52.38 Ammonia nitrogen concentration (mg / L) 10.64 10.35 10.29 13.2 13.82 10.87 Total phosphorus concentration (mg / L) 0.11 0.15 0.13 0.34 0.47 0.16

[0069] As shown in Table 1, the compressive strength of Example 3 without the addition of modified adsorption fibers was lower than that of the Example 3. This was due to the increased dry density and decreased compressive strength and porosity caused by the internal collapse of the slumped sample. Comparative Examples 1 and 2 show that the addition of β-type hydroxyl iron oxide nanopowder and the introduction of hydrolyzed polymaleic anhydride both contribute to improving the adsorption effect on nitrogen and phosphorus, with the introduction of hydrolyzed polymaleic anhydride having a more significant effect.

[0070] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0071] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a self-activating denitrification and phosphorus removal functional filler, characterized in that, Includes the following steps: Step 1: Add cement, pyrite powder, high-alumina bauxite aggregate, modified adsorbent fiber, foam stabilizer and polycarboxylate superplasticizer to the mixer, mix at 120-200 r / min for 2-3 min, then add water and continue mixing for 5-10 min to obtain slurry; Step 2: Add animal protein foaming agent and water to a foaming machine at a mass ratio of 1:30-50 and foam to obtain a density of 0.06-0.08 g / cm³. 3 foam; Step 3: Add the foam and slurry to a mixer at a mass ratio of 1:4, mix at 600-800 rpm for 3-5 minutes, pour into a mold, cure at 20-25℃ for 3-5 days, then crush to obtain a density of 1.2-1.5 g / cm³. 3 Self-activating denitrification and phosphorus removal functional filler; The ratio of cement, pyrite powder, high-alumina bauxite aggregate, modified adsorbent fiber, foam stabilizer, water-reducing agent and water in step one is 20-40:15-30:15-30:10-20:0.05-0.15:0.1-0.3:6-12; The modified adsorption fiber is prepared by the following steps: Add a 1.5-2 g / L dopamine hydrochloride aqueous solution to the reactor, adjust the pH to 8.5 with a 0.5-1 mol / L Tris-HCl buffer solution, then add pre-etched basalt fibers and porous composite particles with modified silane. Stir at 20-25℃ and 120-200 r / min for 20-24 h, filter, wash the product with deionized water until the final wash solution is neutral, and vacuum dry to obtain modified adsorption fibers. The porous composite particles are prepared by the following steps: Hydrolyzed polymaleic anhydride, 3-glycidyl etheroxypropyltrimethoxysilane, benzyltriethylamine chloride and anhydrous toluene were added to a reaction vessel and reacted at 117-120℃ for 6-8 hours under nitrogen protection. The temperature was then lowered to 60-65℃, sodium hydroxide powder and calcium oxide powder were added, and the reaction was continued for 3-3.5 hours. Diatomaceous earth was then added and kept at the same temperature for 0.5-1 hours. The mixture was filtered, and the filtrate was distilled under reduced pressure. The product was then dried to obtain modified silane. Ferric chloride, polyvinylpyrrolidone, and deionized water were added to a reaction vessel and stirred at 200-500 r / min for 10-20 min. Then, stirring was continued at 85-90℃ for 150-180 min. The mixture was allowed to cool naturally, centrifuged, filtered, and the product was washed 3-5 times with anhydrous ethanol and deionized water, respectively. The product was then vacuum dried and pulverized to obtain β-type ferric hydroxide nanopowder. After uniformly mixing activated carbon powder and β-type hydroxy iron oxide nanoparticles, the mixture was transferred to a reaction vessel, and anhydrous toluene, anhydrous pyridine, and modified silane were added. The mixture was then reacted under nitrogen protection at 80-85℃ for 20-24 hours. After filtration, washing, and vacuum drying, porous composite particles were obtained.

2. The preparation method of the self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The ratio of the amounts of hydrolyzed polymaleic anhydride, 3-glycidyl etheroxypropyltrimethoxysilane, benzyltriethylamine chloride, anhydrous toluene, sodium hydroxide powder, calcium oxide powder, and diatomaceous earth is 3-4g: 2.5-3g: 0.5-0.6g: 50mL: 0.1-0.2g: 0.05-0.1g: 1.5-2g.

3. The method for preparing a self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The ratio of the amount of dopamine hydrochloride aqueous solution, pre-etched basalt fiber and porous composite particles is 80-100mL: 1-1.2g: 0.4-0.6g.

4. The preparation method of the self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The foam stabilizer is methylcellulose or hydroxypropyl methylcellulose ether.

5. The method for preparing a self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The activated carbon powder, β-type hydroxy iron oxide nanopowder, anhydrous toluene, anhydrous pyridine and modified silane are in the following proportions: 1.5-2g: 1g: 80-100mL: 2-3mL: 12.5-15g.

6. The method for preparing a self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The ratio of ferric chloride, polyvinylpyrrolidone, and deionized water is 3-5g: 2-3g: 200-250mL.

7. The method for preparing a self-activating denitrification and phosphorus removal functional filler according to claim 1, characterized in that, The pre-etched basalt fiber is prepared by the following steps: Basalt fibers are transferred to a stirred tank, and a sulfuric acid solution with a mass fraction of 5-8% is added to the stirred tank to immerse the basalt fibers. The fibers are then ultrasonically dispersed for 40-60 minutes, filtered, and the treated basalt fibers are washed with deionized water until the final washing solution is neutral. The fibers are then dried to obtain pre-etched basalt fibers.

8. The application of the self-activated denitrification and phosphorus removal functional packing material prepared by any one of claims 1-7 in water treatment.