Composite phosphorus removal agent, preparation method and application thereof

Abstract

The application belongs to the technical field of preparation of phosphorus removal agents, and particularly relates to a composite phosphorus removal agent, a preparation method and application thereof. The composite phosphorus removal agent comprises a honeycomb carrier and microspheres; the microspheres are loaded on the honeycomb carrier; and the preparation raw material of the microspheres comprises polyvinylidene fluoride particles, graphene oxide, ZrOCl2 and polyphosphorus bacteria. The composite phosphorus removal agent comprises a honeycomb carrier and microspheres and microcapsules loaded on the honeycomb carrier; the microspheres capture phosphate in water and perform biological phosphorus removal and adsorption phosphorus removal; and the honeycomb carrier itself also has the effect of adsorbing phosphate; the two remove phosphate in water in cooperation, which not only improves the phosphorus removal effect of the phosphorus removal agent, but also does not increase the burden of the water body.

Description

Technical Field

[0001] This invention belongs to the field of phosphorus removal agent preparation technology, specifically relating to a composite phosphorus removal agent, its preparation method, and its application. Background Technology

[0002] Phosphorus removal agents play a crucial role in the treatment of eutrophication in water bodies, particularly in wastewater treatment and mine wastewater treatment. Existing phosphorus removal technologies mainly include adsorption, chemical precipitation, biological phosphorus removal, and combined phosphorus removal. Adsorption uses adsorbents to adsorb phosphorus from water; these adsorbents include activated carbon, biomass, metal oxides, and silica-based mesoporous molecular sieves. However, it suffers from limited adsorption capacity and the influence of coexisting ions. Chemical precipitation (such as aluminum, iron, and calcium salts) is a traditional phosphorus removal method, but it suffers from large amounts of sludge and secondary pollution. Biological phosphorus removal has gained attention because it does not require large amounts of chemical reagents, but it has high requirements for the aquatic environment, and polyphosphate-accumulating bacteria are easily deactivated. Existing combined phosphorus removal technologies generally combine chemical precipitation with adsorption, or chemical precipitation with biological phosphorus removal. Even these simple combined phosphorus removal technologies can still cause secondary water pollution. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a composite phosphorus removal agent, its preparation method, and its application. The composite phosphorus removal agent organically combines adsorption and biological phosphorus removal methods, which not only improves the phosphorus removal effect of the phosphorus removal agent but also does not increase the burden on water bodies.

[0004] This invention is achieved through the following technical solution:

[0005] In a first aspect, the present invention provides a composite phosphorus removal agent, comprising a honeycomb carrier and microspheres;

[0006] The microspheres are loaded onto the cellular carrier;

[0007] The raw materials for preparing the microspheres include polyvinylidene fluoride particles, graphene oxide, ZrOCl2, and polyphosphate bacteria.

[0008] Secondly, the present invention provides a method for preparing a composite phosphorus removal agent, comprising the following steps:

[0009] Microspheres are loaded onto a cellular carrier.

[0010] Thirdly, this invention provides an application of a composite phosphorus removal agent in the field of water treatment.

[0011] The composite phosphorus removal agent and its preparation method provided by this invention have at least the following beneficial technical effects compared with the prior art:

[0012] (1) The composite phosphorus removal agent of the present invention includes a honeycomb carrier and microspheres and microcapsules loaded on the honeycomb carrier; the microspheres capture phosphate in the water and perform biological phosphorus removal and adsorption phosphorus removal; while the honeycomb carrier itself also has the effect of adsorbing phosphate; the two work together to remove phosphate in the water, which not only improves the phosphorus removal effect of the phosphorus removal agent, but also does not increase the burden on the water.

[0013] (2) The preparation method of the composite phosphorus removal agent of the present invention loads microspheres and microcapsules on a honeycomb carrier, and organically combines adsorption method and biological phosphorus removal method to obtain a composite phosphorus removal agent with extremely high selectivity for phosphate. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0015] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0016] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0017] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0018] A first aspect of this invention provides a composite phosphorus removal agent, comprising a honeycomb carrier and microspheres; the microspheres are loaded on the honeycomb carrier;

[0019] The raw materials for preparing microspheres include polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), ZrOCl2, and polyphosphate bacteria.

[0020] The composite phosphorus removal agent provided in this invention uses microspheres loaded on a honeycomb carrier. The microspheres capture phosphate ions in the water, performing both biological and adsorption-based phosphorus removal while simultaneously isolating the aquatic environment (salt concentration, pH, etc.) to prevent it from affecting the activity of polyphosphate-accumulating bacteria, thus maintaining their high activity for an extended period. The honeycomb carrier itself also adsorbs phosphate. These three components work synergistically to remove phosphate from the water, improving the phosphorus removal effect without increasing the burden on the water body. Furthermore, the honeycomb carrier loading method allows for easy removal of the phosphorus from the water after removal, preventing the generation of excessive sludge.

[0021] In some embodiments, the cellular carrier includes a cordierite cellular carrier.

[0022] In some embodiments, the cordierite material in the cordierite honeycomb carrier has a CAS number of 1302-88-1.

[0023] In some embodiments, the average particle size of the microspheres is 5 μm to 10 μm.

[0024] In some embodiments, the surface of polyvinylidene fluoride particles in the microspheres is loaded with graphene oxide sheets, and polyphosphate bacteria and hydrated zirconium oxide nanoclusters are attached to the surface of the graphene oxide sheets.

[0025] In some embodiments, the number of graphene oxide sheets loaded and attached to the surface of the polyvinylidene fluoride particles is two or more.

[0026] In some embodiments, the average particle size of the polyvinylidene fluoride particles is 1 μm to 3 μm.

[0027] In some embodiments, the average molecular weight of polyvinylidene fluoride is 100,000 to 200,000. It should be noted that the average molecular weight of polyvinylidene fluoride provided in the embodiments of the present invention is only a range given to clarify the technical solution of the embodiments of the present invention, and the average molecular weight in actual production is not limited to this.

[0028] In some embodiments, the CAS number of polyvinylidene fluoride is 24937-79-9.

[0029] In some embodiments, the average sheet diameter of graphene oxide is 10 μm to 30 μm. In some embodiments, the average thickness of graphene oxide is 0.8 nm to 1 nm. It should be noted that the average sheet diameter and average thickness of graphene oxide provided in the embodiments of the present invention are only ranges given to clarify the technical solutions of the embodiments of the present invention, and the average sheet diameter and average thickness in actual production are not limited to these.

[0030] In some embodiments, the polyphosphate bacteria selected are those produced by Shandong Nuoweihai Biotechnology Co., Ltd., with product standard number Q / 371701NWH 007-2023.

[0031] In some embodiments, the mass ratio of polyvinylidene fluoride to graphene oxide is 1:(600~800).

[0032] In some embodiments, the mass ratio of Zr to GO in graphene oxide (GO) and ZrOCl2 is 1:(2~5).

[0033] In some embodiments, the mass ratio of graphene oxide to polyphosphate bacteria is 1:(10~20).

[0034] A second aspect of this invention provides a method for preparing the above-mentioned composite phosphorus removal agent, comprising the following steps:

[0035] S10. Load the microspheres onto the cellular carrier.

[0036] The method for preparing the composite phosphorus removal agent provided in this invention involves loading microspheres onto a honeycomb carrier. The resulting composite phosphorus removal agent combines adsorption and biological phosphorus removal mechanisms, exhibiting extremely high selectivity for phosphates.

[0037] In some embodiments, the preparation of microspheres in step S10 above includes the following steps:

[0038] S101. Filter the mixed slurry;

[0039] The mixed slurry contains polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), hydrated zirconium oxide sol, and polyphosphate-accumulating bacteria.

[0040] In the preparation of the above microspheres, the mixed slurry is filtered to remove water. Polyvinylidene fluoride (PVDF) particles serve as the supporting matrix, and graphene oxide sheets are stacked layer by layer on the surface of the PVDF particles to form a membrane together with hydrated zirconium oxide sol and polyphosphate bacteria.

[0041] In some embodiments, in step S101 above, the concentration of the hydrated zirconium oxide sol is 10% to 20%.

[0042] In some embodiments, the preparation of hydrated zirconium oxide sol in step S101 above includes the following steps:

[0043] The solid obtained by hydrolyzing the S1011.ZrOCl2 aqueous solution was then mixed with water.

[0044] In some embodiments, in step S1011 above, the concentration of the ZrOCl2 aqueous solution is 0.1 mol / L to 0.2 mol / L.

[0045] In some embodiments, the preparation of the ZrOCl2 aqueous solution in step S1011 above includes the following steps: mixing ZrOCl2·8H2O with water.

[0046] In some embodiments, the hydrolysis treatment in step S1011 above includes the following steps:

[0047] S10111. Add alkali solution dropwise to the ZrOCl2 aqueous solution while stirring.

[0048] In some embodiments, in step S10111 above, the stirring rate is 600 rpm to 800 rpm.

[0049] In some embodiments, in step S10111 above, the alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution.

[0050] In some embodiments, the concentration of the sodium hydroxide solution is 0.5 mol / L to 1.5 mol / L.

[0051] In some embodiments, the concentration of the potassium hydroxide solution is 0.5 mol / L to 1.5 mol / L.

[0052] In some embodiments, in step S10111 above, the dripping rate of the alkali solution is 10d / min to 20d / min.

[0053] In some embodiments, during step S1011 described above, the pH value of the hydrolysis treatment is 10-11. In this case, Zr 4+ It can be completely hydrolyzed and precipitated.

[0054] In some embodiments, the step of obtaining the solid in step S1011 above includes:

[0055] S10112. Filter the hydrolyzed product and wash it until it is neutral.

[0056] In the above steps of obtaining solids, washing removes chloride ions, as well as at least one of sodium ions and potassium ions, from the hydrolyzed product.

[0057] In some embodiments, in step S10112 above, deionized water is used to wash the hydrolyzed product.

[0058] In some embodiments, the step of mixing with water in step S1011 above includes:

[0059] S10113. Under ultrasonic conditions, the solid is dispersed in water according to the concentration of the target hydrated zirconium oxide sol.

[0060] In some embodiments, in step S10113 above, the ultrasonic power is 100W~200W.

[0061] In some embodiments, the preparation of the mixed slurry in step S101 above includes the following steps:

[0062] S1012. Under stirring, the graphene oxide dispersion and hydrated zirconium oxide sol are ultrasonically mixed in a water bath;

[0063] The graphene oxide dispersion contains graphene oxide and polyphosphate-accumulating bacteria.

[0064] In the preparation of the above-mentioned mixed slurry, the nanoclusters of hydrated zirconium oxide can be attached to the GO sheets under stirring and water bath ultrasonic environment.

[0065] In some embodiments, in step S1012 above, the stirring rate is 500 rpm to 600 rpm.

[0066] In some embodiments, the preparation of the graphene oxide dispersion in step S1012 above includes the following steps:

[0067] S10121. Under stirring, graphene oxide, polyphosphate bacteria and water are ultrasonically dispersed in a water bath.

[0068] In the preparation of the above graphene oxide dispersion, polyphosphate bacteria are attached to the GO sheets under stirring and water bath ultrasonic environment.

[0069] In some embodiments, in step S10121 above, the stirring rate is 500 rpm to 600 rpm.

[0070] In some embodiments, in step S10121 above, the water bath in the ultrasonic dispersion is an ice water bath.

[0071] In some embodiments, during the ultrasonic dispersion in the water bath in step S10121 described above, the ultrasonic power is 100W~120W.

[0072] In some embodiments, in step S10121 above, the time for ultrasonic dispersion in the water bath is 3h to 6h.

[0073] In some embodiments, in step S1012 above, the water bath in the ultrasonic mixing process is an ice water bath.

[0074] In some embodiments, during step S1012 above, the ultrasonic power in the water bath ultrasonic mixing is 100W~120W.

[0075] In some embodiments, in step S1012 above, the time for ultrasonic mixing in the water bath is 5h to 8h.

[0076] In some embodiments, the preparation of microspheres in step S10 above further includes the following steps:

[0077] S102. Dry the filter cake obtained by vacuum filtration.

[0078] In some embodiments, in step S102 above, the drying method is air drying or low-temperature drying.

[0079] In some embodiments, the low-temperature drying temperature is 20℃~25℃. It should be noted that the low-temperature drying time can be adjusted according to the actual situation, and is not particularly limited in the embodiments of the present invention.

[0080] In some embodiments, the step of loading microspheres onto a cellular carrier in step S10 above includes:

[0081] S103. Coating the mixed slurry and the honeycomb carrier;

[0082] The mixed slurry includes microspheres and additives.

[0083] In some embodiments, in step S103 above, the volume ratio of microspheres, microcapsules and adjuvants is 1:1:(5~8).

[0084] In some embodiments, in step S103 above, the additives include dispersants, binders, pH adjusters and water.

[0085] In some embodiments, the mass ratio of dispersant to binder is 1:1. It should be noted that the amounts of pH adjuster and water can be adjusted according to the actual preparation process, as long as the pH and viscosity requirements of the mixed slurry are met.

[0086] In some embodiments, the dispersant includes at least one of polyvinylpyrrolidone and polyether-modified polydimethylsiloxane. In this case, polyvinylpyrrolidone and polyether-modified polydimethylsiloxane can exist stably under acidic conditions and exert their dispersant effect.

[0087] In some embodiments, the CAS number of polyvinylpyrrolidone is 9003-39-8.

[0088] In some embodiments, the polyether-modified polydimethylsiloxane comprises symmetrical monomethacryloyloxypropyl-modified polydimethylsiloxane.

[0089] In some embodiments, the CAS number of the symmetrical monomethacryloyloxypropyl modified polydimethylsiloxane is 868684-55-3.

[0090] In some embodiments, the adhesive includes at least one of γ-glycidoxypropyltrimethoxysilane (KH-560), γ-methacryloyloxypropyltrimethoxysilane (KH-570), and γ-aminopropyltriethoxysilane (KH-550).

[0091] In some embodiments, the pH adjuster includes at least one of formic acid and acetic acid. In this case, formic acid and acetic acid can slowly adjust the pH of the system and are easily released or removed during subsequent sintering.

[0092] In some embodiments, in step S103 above, the pH value of the mixed slurry is 4-5. In this case, the mixed slurry can exist stably without sedimentation or chemical degradation.

[0093] In some embodiments, in step S103 above, the preparation of the mixed slurry includes the following steps:

[0094] S1031. Under stirring, after the pH of the water is adjusted to the target value by the pH adjuster, the dispersant, microspheres, microcapsules and binder are added in sequence.

[0095] In some embodiments, in step S1031 above, the stirring speed is 200 rpm to 300 rpm.

[0096] In some embodiments, in step S103 above, the viscosity of the mixed slurry is 50 mPa·s to 70 mPa·s.

[0097] In some embodiments, the volume ratio of the mixed slurry to the cell carrier is (100~200):1. In this case, the cell carrier can be completely immersed in the mixed slurry and fully loaded.

[0098] In some embodiments, in step S103 above, the coating includes the following steps:

[0099] S1032. The honeycomb carrier and the mixed slurry are circulated for impregnation, lifting and drying.

[0100] In some embodiments, in step S1032 above, the impregnation, lifting, and drying steps are repeated three times or more. In this case, three cycles can ensure that the mixed slurry is fully coated on the honeycomb carrier.

[0101] In some embodiments, in step S1032 above, the immersion, pull-out, and drying steps are repeated 3 to 5 times. In this case, it can ensure that the mixed slurry is fully loaded, while preventing excessive loading that would reduce the function of the descaling agent.

[0102] In some embodiments, the impregnation time in step S1032 is 30s to 60s. In this case, the mixed slurry fully wets the honeycomb carrier without causing the honeycomb carrier structure to collapse (excessive time can easily cause the slurry to over-wet and penetrate into the honeycomb carrier, thereby causing structural collapse).

[0103] In some embodiments, in step S1032 above, the lifting rate is 3 cm / min to 8 cm / min. In this case, the slow lifting rate allows the mixed slurry to be uniformly coated on the honeycomb carrier without causing pore blockage.

[0104] In some embodiments, in step S1032 above, drying includes the following steps:

[0105] S10321. The cellular carrier is air-dried at room temperature and then heated to 30℃~37℃ and kept warm.

[0106] In the above drying process, the surface moisture of the impregnated honeycomb carrier is removed by air drying to prevent it from dripping; the temperature is raised to 80℃~100℃ and kept at that temperature to remove the free moisture inside the impregnated honeycomb carrier; and slow drying ensures that the surface coating slurry of the honeycomb carrier is free of cracks (rapid evaporation of surface moisture can easily lead to cracks).

[0107] Room temperature refers to a temperature of 20℃~25℃.

[0108] In some embodiments, in step S10521 above, the air-drying time is 3h to 4h.

[0109] In some embodiments, in step S10521 above, the heating rate is 2℃ / min to 5℃ / min.

[0110] In some embodiments, in step S10521 above, the heat preservation time is 4h~5h.

[0111] The following description, in conjunction with specific embodiments, provides further details. For ease of explanation, the following embodiments and comparative examples involve:

[0112] (1) The honeycomb carrier is cordierite honeycomb carrier, and the CAS number of cordierite material is 1302-88-1.

[0113] (2) The average particle size of the polyvinylidene fluoride particles is 2 μm, the average molecular weight is 100,000, and the CAS number is 24937-79-9.

[0114] (3) The average sheet diameter of graphene oxide is 25 μm and the average thickness is 1 nm.

[0115] (4) Polyphosphate bacteria are polyphosphate bacteria produced by Shandong Nuoweihai Biotechnology Co., Ltd. with product standard number Q / 371701NWH007-2023.

[0116] (5) The preparation steps of hydrated zirconium oxide sol are as follows:

[0117] 1) Mix ZrOCl2·8H2O with water to prepare a ZrOCl2 aqueous solution with a concentration of 0.2 mol / L;

[0118] 2) Under stirring at 700 rpm, add a 1.5 mol / L sodium hydroxide solution dropwise to the ZrOCl2 aqueous solution at a rate of 15 d / min until the pH of the system is 11;

[0119] 3) After filtering the hydrolyzed product, wash it with deionized water until neutral, and collect the solid.

[0120] 4) The solid was mixed with water under ultrasonic conditions of 200W to prepare a 15% hydrated zirconium oxide sol.

[0121] (6) During coating, the volume ratio of the mixed slurry to the honeycomb carrier is 150:1.

[0122] (7) The CAS number of polyvinylpyrrolidone is 9003-39-8.

[0123] Example 1

[0124] Example 1 provides a composite phosphorus removal agent, which consists of a honeycomb carrier and microspheres, with the microspheres loaded on the honeycomb carrier;

[0125] The raw materials for preparing the microspheres include polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), ZrOCl2, and polyphosphate-accumulating bacteria. Among them, the surface of the PVDF particles is loaded with two or more layers of graphene oxide sheets, and the surface of the graphene oxide sheets is attached with polyphosphate-accumulating bacteria and hydrated zirconium oxide nanoclusters. The mass ratio of PVDF to graphene oxide is 1:600. In graphene oxide (GO) and ZrOCl2, the mass ratio of Zr to GO is 1:2. The mass ratio of graphene oxide to polyphosphate-accumulating bacteria is 1:15.

[0126] This embodiment also provides a method for preparing the composite phosphorus removal agent of this embodiment, the steps of which are as follows:

[0127] E1. Preparation of microspheres

[0128] E1-1. Preparation of graphene oxide dispersion: Graphene oxide, polyphosphate bacteria and water were ultrasonically dispersed in an ice-water bath for 4 hours under stirring at 600 rpm, with an ultrasonic power of 100 W, to obtain graphene oxide dispersion.

[0129] E1-2. Preparation of the mixed slurry: The graphene oxide dispersion and hydrated zirconium oxide were ultrasonically mixed in an ice-water bath for 5 hours under stirring at 600 rpm, with an ultrasonic power of 100 W, to obtain the mixed slurry.

[0130] E1-3. The mixed slurry is filtered to obtain a filter cake, which is then dried at a low temperature of 25℃ to obtain microspheres.

[0131] E2. Load

[0132] E2-1. Preparation of mixed slurry: Under stirring at 300 rpm, formic acid (pH adjuster) was used to adjust the pH of water to 4, and then polyvinylpyrrolidone (dispersant), microspheres and KH-560 (binder) were added in sequence to obtain a mixed slurry with a viscosity of 63.4 mPa·s.

[0133] E2-2. Coating: The honeycomb carrier and the mixed slurry are cyclically impregnated, pulled up and dried 4 times; wherein, the single impregnation time is 50s, the pulling rate is 6cm / min, and the drying is to let the impregnated honeycomb carrier air dry at room temperature for 4h, then heat it to 35℃ at a heating rate of 4℃ / min and keep it at that temperature for 4h to obtain the composite dephosphorizing agent provided in the embodiment of the present invention.

[0134] Example 2

[0135] Example 2 provides a composite phosphorus removal agent with a composition basically the same as that of Example 1, except that:

[0136] In the raw materials for preparing microspheres, the mass ratio of polyvinylidene fluoride to graphene oxide is 1:800; in graphene oxide (GO) and ZrOCl2, the mass ratio of Zr to GO is 1:5; and the mass ratio of graphene oxide to polyphosphate bacteria is 1:10.

[0137] This embodiment also provides a method for preparing the composite phosphorus removal agent of this embodiment, the steps of which are basically the same as those in Example 1, except that:

[0138] E1-1. Preparation of graphene oxide dispersion: Graphene oxide, polyphosphate bacteria and water were ultrasonically dispersed in an ice-water bath for 6 hours under stirring at 500 rpm, with an ultrasonic power of 120 W, to obtain graphene oxide dispersion.

[0139] E1-2. Preparation of the mixed slurry: The graphene oxide dispersion and hydrated zirconium oxide were ultrasonically mixed in an ice-water bath for 7 hours under stirring at 500 rpm, with an ultrasonic power of 120 W, to obtain the mixed slurry.

[0140] Example 3

[0141] Example 3 provides a composite phosphorus removal agent with a composition basically the same as that of Example 1, except that:

[0142] In the raw materials for preparing microspheres, the mass ratio of polyvinylidene fluoride to graphene oxide is 1:700; in graphene oxide (GO) and ZrOCl2, the mass ratio of Zr to GO is 1:4; and the mass ratio of graphene oxide to polyphosphate bacteria is 1:20.

[0143] This embodiment also provides a method for preparing the composite phosphorus removal agent of this embodiment, the steps of which are basically the same as those in Example 1, except that:

[0144] E1-1. Preparation of graphene oxide dispersion: Graphene oxide, polyphosphate bacteria and water were ultrasonically dispersed in an ice-water bath for 5 hours under stirring at 600 rpm, with an ultrasonic power of 120 W, to obtain graphene oxide dispersion.

[0145] E1-2. Preparation of the mixed slurry: The graphene oxide dispersion and hydrated zirconium oxide were ultrasonically mixed in an ice-water bath for 8 hours under stirring at 600 rpm, with an ultrasonic power of 120 W, to obtain the mixed slurry.

[0146] Example 4

[0147] Example 4 provides a method for preparing the composite phosphorus removal agent of Example 1, the steps of which are basically the same as those of Example 1, except that:

[0148] E2-1. Preparation of mixed slurry: Under stirring at 200 rpm, formic acid (pH adjuster) was used to adjust the pH of water to 5, and then polyvinylpyrrolidone (dispersant), microspheres, microcapsules and KH-560 (binder) were added in sequence to obtain a mixed slurry with a viscosity of 68.8 mPa·s.

[0149] E2-2. Coating: The honeycomb carrier and the mixed slurry are cyclically impregnated, pulled up and dried 5 times; wherein, the single impregnation time is 30s, the pulling rate is 3cm / min, and the drying is to let the impregnated honeycomb carrier air dry at room temperature for 3h, then heat it to 30℃ at a heating rate of 2℃ / min and keep it at that temperature for 5h.

[0150] Example 5

[0151] Example 5 provides a method for preparing the composite phosphorus removal agent of Example 1, the steps of which are basically the same as those of Example 1, except that:

[0152] E2-1. Preparation of mixed slurry: Under stirring at 200 rpm, formic acid (pH adjuster) was used to adjust the pH of water to 4, and then polyvinylpyrrolidone (dispersant), microspheres, microcapsules and KH-560 (binder) were added in sequence to obtain a mixed slurry with a viscosity of 51.7 mPa·s.

[0153] E2-2. Coating: The honeycomb carrier and the mixed slurry are cyclically impregnated, pulled up and dried three times; the single impregnation time is 60s, the pulling rate is 8cm / min, and the drying is to let the impregnated honeycomb carrier air dry at room temperature for 4h, then heat it to 37℃ at a heating rate of 5℃ / min and keep it at that temperature for 5h.

[0154] Comparative Example 1

[0155] Comparative Example 1 provides a composite phosphorus removal agent, which is composed of a honeycomb carrier, polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), ZrOCl2 and polyphosphate-accumulating bacteria;

[0156] Polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), ZrOCl2, and polyphosphate-accumulating bacteria were all loaded onto a honeycomb carrier. Specifically, the PVDF particles had two or more layers of graphene oxide sheets attached to their surface, and the graphene oxide sheets were coated with polyphosphate-accumulating bacteria and hydrated zirconium oxide nanoclusters. The mass ratio of PVDF to graphene oxide was 1:600; in both GO and ZrOCl2, the mass ratio of Zr to GO was 1:3; and the mass ratio of graphene oxide to polyphosphate-accumulating bacteria was 1:10.

[0157] This comparative example also provides a method for preparing the composite phosphorus removal agent of this comparative example, the steps of which are as follows:

[0158] D1. Preparation of mixed slurry: Under stirring at 300 rpm, after adjusting the pH of water to 4 with formic acid (pH adjuster), polyvinylpyrrolidone (dispersant), polyvinylidene fluoride (PVDF) particles, graphene oxide (GO), ZrOCl2, polyphosphate bacteria and KH-560 (binder) were added in sequence to obtain a mixed slurry with a viscosity of 117.2 mPa·s.

[0159] D2. Coating: The honeycomb carrier and the mixed slurry are cyclically impregnated, pulled up and dried 4 times; the single impregnation time is 30s and the pulling rate is 3cm / min; the drying is to let the impregnated honeycomb carrier air dry at room temperature for 3h and then heat it to 30℃ at a heating rate of 2℃ / min and keep it at that temperature for 4h.

[0160] Comparative Example 2

[0161] Comparative Example 2 provides a method for preparing a composite phosphorus removal agent, the steps of which are basically the same as those in Example 1, except that:

[0162] E2-1. Preparation of mixed slurry: Under stirring at 400 rpm, formic acid (pH adjuster) was used to adjust the pH of water to 7, and then polyvinylpyrrolidone (dispersant), microspheres, microcapsules and KH-560 (binder) were added in sequence to obtain a mixed slurry with a viscosity of 80.6 mPa·s.

[0163] E2-2. Coating: The honeycomb carrier and the mixed slurry are cyclically impregnated, pulled up and dried 6 times; the single impregnation time is 30s and the pulling rate is 10cm / min; the drying is to let the impregnated honeycomb carrier air dry at room temperature for 3h, then heat it to 40℃ at a heating rate of 10℃ / min and keep it at that temperature for 4h.

[0164] To verify the advancement of the composite phosphorus removal agent and its preparation method provided in the embodiments of the present invention, the following experiments were conducted on the composite phosphorus removal agents prepared by the preparation methods provided in the embodiments and comparative examples of the present invention:

[0165] A solution with an initial phosphorus concentration of 40 mg / L was prepared using sodium phosphate and water. The composite phosphorus removal agent prepared by the methods in the examples and comparative examples was added at a concentration of 20 g / L. Samples were then taken at different time points of 1 min, 10 min, 20 min, 30 min, and 60 min to detect the residual phosphorus content in the solution, as shown in Table 1 below.

[0166]

[0167] The following conclusions can be drawn from Table 1 above:

[0168] (1) Based on the data from Example 1 and Comparative Example 1, the phosphorus removal efficiency of the composite phosphorus removal agent prepared by directly loading the raw materials for microsphere preparation onto a honeycomb carrier in Comparative Example 1 was significantly reduced. This is because polyphosphate-accumulating bacteria are directly exposed to a strongly alkaline sodium phosphate solution, leading to their inactivation. Therefore, it can be seen that in the composite phosphorus removal agent provided by the embodiments of the present invention, the microspheres made of polyphosphate-accumulating bacteria can block the aquatic environment (sodium phosphate solution), so that the aquatic environment (salt concentration, pH value, etc.) cannot affect the activity of polyphosphate-accumulating bacteria, allowing polyphosphate-accumulating bacteria to maintain high activity for a long time.

[0169] (2) Based on the data from Example 1 and Comparative Example 2, Comparative Example 2, under loading conditions, increased the viscosity of the mixed slurry, the number of cycles (6 times), the pulling rate, the heating rate, and the drying temperature, resulting in poor loading of microspheres and microcapsules on the honeycomb carrier, thereby significantly reducing the phosphorus removal effect of the composite phosphorus removal agent. Therefore, it can be seen that the preparation method of the composite phosphorus removal agent provided in this embodiment of the invention, under reasonable mixed slurry viscosity, number of cycles, pulling rate, heating rate, and drying temperature, significantly improves the phosphorus removal effect of the prepared composite phosphorus removal agent.

[0170] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A composite phosphorus removal agent, characterized in that, It includes a cellular carrier and microspheres; the microspheres are loaded on the cellular carrier; The raw materials for preparing microspheres include polyvinylidene fluoride particles, graphene oxide, ZrOCl2, and polyphosphate bacteria; The honeycomb carrier includes a cordierite honeycomb carrier; The mass ratio of the polyvinylidene fluoride to the graphene oxide is 1:600~800; In the graphene oxide and ZrOCl2, the mass ratio of Zr to GO is 1:2~5; The mass ratio of the graphene oxide to the polyphosphate-accumulating bacteria is 1:10~20; The preparation method of the composite phosphorus removal agent includes the following steps: loading microspheres onto a honeycomb carrier; The preparation of the microspheres includes the following steps: The mixed slurry was filtered. The mixed slurry contains polyvinylidene fluoride particles, graphene oxide, hydrated zirconium oxide sol, and polyphosphate bacteria; The step of loading microspheres onto a honeycomb carrier includes: coating the mixed slurry and the honeycomb carrier; The mixed slurry includes microspheres and additives; The preparation of the hydrated zirconium oxide sol includes the following steps: ZrOCl2 aqueous solution was hydrolyzed to obtain a solid, which was then mixed with water. The coating process includes the following steps: cyclic impregnation of the honeycomb carrier with the mixed slurry, followed by a lifting and drying process.

2. The composite phosphorus removal agent according to claim 1, characterized in that, It satisfies at least one of the following characteristics (1) to (7): (1) The average particle size of the microspheres is 5 μm to 10 μm; (2) In the microspheres, polyvinylidene fluoride particles are loaded with graphene oxide sheets, and polyphosphate bacteria and hydrated zirconium oxide nanoclusters are attached to the surface of the graphene oxide sheets. (3) The average particle size of the polyvinylidene fluoride particles is 1 μm to 3 μm; (4) The average molecular weight of the polyvinylidene fluoride is 100,000 to 200,000; (5) The average sheet diameter of the graphene oxide is 10 μm to 30 μm; (6) The average thickness of the graphene oxide is 0.8 nm to 1 nm; (7) The number of graphene oxide sheets loaded and attached to the surface of the polyvinylidene fluoride particles is two or more.

3. A method for preparing the composite phosphorus removal agent as described in claim 1 or 2, characterized in that, Includes the following steps: Microspheres are loaded onto a cellular carrier.

4. The preparation method of the composite phosphorus removal agent according to claim 3, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) The concentration of the hydrated zirconium oxide sol is 10%~20%; (2) The volume ratio of the microspheres to the additive is 1:5~8; (3) The additives include dispersants, binders, pH adjusters, and water; (4) The pH value of the mixed slurry is 4~5; (5) The viscosity of the mixed slurry is 50 mPa·s to 70 mPa·s; (6) The volume ratio of the mixed slurry to the honeycomb carrier is 100~200:

1.

5. The method for preparing the composite phosphorus removal agent according to claim 4, characterized in that, It satisfies at least one of the following characteristics (1) to (13): (1) The concentration of the ZrOCl2 aqueous solution is 0.1 mol / L to 0.2 mol / L; (2) The hydrolysis treatment includes the following steps: adding alkaline solution dropwise to the ZrOCl2 aqueous solution under stirring; (3) The pH value of the hydrolysis treatment is 10~11; (4) The step of obtaining the solid includes: filtering the hydrolyzed product and washing it until it is neutral; (5) The step of mixing with water includes: dispersing the solid in water under ultrasonic conditions according to the concentration of the target hydrated zirconia sol; (6) The mass ratio of the dispersant to the binder is 1:1; (7) The dispersant includes at least one of polyvinylpyrrolidone and polyether-modified polydimethylsiloxane; (8) The adhesive comprises at least one of γ-glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-aminopropyltriethoxysilane; (9) The pH adjuster includes at least one of formic acid and acetic acid; (10) The cyclic soaking, lifting and drying steps are repeated more than 3 times; (11) The immersion time is 30s~60s; (12) The lifting rate is 3cm / min to 8cm / min; (13) In the coating process, drying includes the following steps: after air drying at room temperature, the temperature is raised to 30℃~37℃ and kept warm.

6. The method for preparing the composite phosphorus removal agent according to claim 5, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) In the hydrolysis process, the stirring rate is 600 rpm to 800 rpm; (2) The alkaline solution includes at least one of sodium hydroxide solution and potassium hydroxide solution; (3) The dripping rate of the alkaline solution is 10d / min to 20d / min; (4) In the step of mixing with water, the ultrasonic power is 100W~200W; (5) The air-drying time is 3h~4h; (6) The heat preservation time is 4h~5h.

7. The method for preparing the composite phosphorus removal agent according to any one of claims 4 to 6, characterized in that, It satisfies at least one of the following characteristics (1) to (2): (1) The preparation of the mixed slurry includes the following steps: The graphene oxide dispersion and the hydrated zirconium oxide sol were mixed by ultrasonic mixing in a water bath under stirring. The graphene oxide dispersion contains graphene oxide and polyphosphate-accumulating bacteria. (2) The preparation of the microspheres also includes the following steps: drying the filter cake obtained by vacuum filtration.

8. The method for preparing the composite dephosphorizing agent according to claim 7, characterized in that, It satisfies at least one of the following characteristics (1) to (6): (1) In the preparation of the mixed slurry, the stirring speed is 500 rpm to 600 rpm; (2) The preparation of the graphene oxide dispersion includes the following steps: Under stirring, graphene oxide, polyphosphate bacteria and water were ultrasonically dispersed in a water bath. (3) In the preparation of the mixed slurry, the water bath is an ice-water bath; (4) In the preparation of the mixed slurry, the ultrasonic power is 100W~120W; (5) In the preparation of the mixed slurry, the water bath ultrasonic mixing time is 5h~8h; (6) In the process of drying the filter cake obtained by vacuum filtration, the drying method is air drying or low-temperature drying.

9. The method for preparing the composite phosphorus removal agent according to claim 8, characterized in that, It satisfies at least one of the following characteristics (1) to (5): (1) In the preparation of the graphene oxide dispersion, the stirring speed is 500 rpm to 600 rpm; (2) In the preparation of the graphene oxide dispersion, the water bath is an ice-water bath; (3) In the preparation of the graphene oxide dispersion, the ultrasonic power is 100W~120W; (4) In the preparation of the graphene oxide dispersion, the ultrasonic dispersion time in the water bath is 3h~6h; (5) The temperature of the low-temperature drying is 20℃~25℃.

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