Phosphorus adsorption material, and preparation method therefor and use thereof

Abstract

Provided in the present application are a phosphorus adsorption material, and a preparation method therefor and the use thereof. The phosphorus adsorption material comprises a porous composite material, wherein the porous composite material comprises porous biomass carbon and polymer fibers at least partially wound around the porous biomass carbon; and the porous composite material contains several amino groups, at least some of which bind to iron ions. Moreover, the phosphorus adsorption material satisfies the following conditions: 0.36 nm≤d002≤0.43 nm, 0.85≤ID / IG≤1.38, B≥240 m2 / g, and 0.20 cm3 / g≤V≤0.56 cm3 / g, wherein d002 represents the interlayer spacing of graphite-like microcrystallites in the phosphorus adsorption material; B represents the specific surface area of the phosphorus adsorption material; and V represents the total pore volume of the phosphorus adsorption material. The phosphorus adsorption material provided in the present application has a high theoretical adsorption capacity for a phosphorus-containing water body having a high or low phosphorus concentration, and can be regenerated and reused.

Description

A phosphorus adsorbent material, its preparation method, and its application.

[0001] This application claims priority to Chinese Patent Application No. 202410955730.0, filed on July 16, 2024, entitled "A Phosphorus Adsorbent Material, Preparation Method and Application", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of water treatment, and more specifically, to a phosphorus adsorbent material, its preparation method, and its application. Background Technology

[0003] With the increase in industrial activity and urbanization, the demand for phosphorus resources has accelerated. Due to the non-renewable nature of phosphate rock, phosphorus resource shortage is a potential challenge facing human society.

[0004] The amount of phosphorus resources entering sewage is enormous, and the continuous discharge of large amounts of phosphorus-containing wastewater into the aquatic environment accelerates the deterioration of water bodies. If it is discharged directly into natural water bodies without treatment, it will pose potential threats to the environment and human health, such as causing eutrophication, indirectly or directly leading to the death of animals and plants, and harming human health, while also causing the loss of phosphorus resources.

[0005] Common technologies for treating phosphorus-containing wastewater include biological, chemical, and physical methods. Biological methods often utilize microorganisms to convert organic phosphorus compounds into inorganic compounds, which are then removed through biosorption and precipitation. However, this requires strict control of parameters such as water quality, temperature, and oxygen levels, and is significantly affected by pH and COD. Chemical methods require the addition of large amounts of chemical reagents, resulting in high costs, large reagent usage, and a tendency to cause secondary pollution. Physical methods mainly employ physical adsorption, but existing adsorbents generally have limited adsorption capacity for phosphorus in phosphorus-containing wastewater, especially for low-phosphorus concentration wastewater.

[0006] Application content

[0007] In view of this, this application provides a phosphorus adsorption material that has a high theoretical adsorption capacity for phosphorus in phosphorus-containing water bodies with high / low phosphorus concentrations, and the phosphorus adsorption material has good chemical stability and can be regenerated and reused.

[0008] This application also provides a method for preparing a phosphorus adsorbent material, which can prepare the above-mentioned phosphorus adsorbent material and the process is simple.

[0009] This application also provides a method for preparing cathode materials using the above-mentioned phosphorus adsorption materials and phosphorus-containing wastewater, which can prepare phosphorus-containing cathode materials.

[0010] In a first aspect, this application provides a porous composite material comprising porous biomass carbon and polymer fibers at least partially wrapped around the porous biomass carbon; the porous composite material contains a plurality of amine groups, at least a portion of which are bonded with iron ions;

[0011] Furthermore, the phosphorus adsorbent material satisfies the following equations 1 to 4: 0.36nm≤d 002 ≤0.43nm (Equation 1); 0.85≤I D / I G ≤1.38 Equation 2; B≥240 m 2 / g Formula 3; 0.20cm 3 / g≤V≤0.56cm 3 / g Formula 4;

[0012] Where, d 002 Indicates the interlayer spacing of graphite-like microcrystals in phosphorus adsorption materials; I D This indicates that the phosphorus adsorbent material shifts at 1300 cm⁻¹ during Raman spectroscopy testing. -1 Up to 1400cm -1 Peak intensity within the range, I G This indicates that the phosphorus adsorbent material shifts at 1550 cm⁻¹ during Raman spectroscopy testing. -1 Up to 1650cm -1 The peak intensity within the range; B is the specific surface area of ​​the phosphorus adsorbent material, and V is the total pore volume of the phosphorus adsorbent material.

[0013] Furthermore, the average pore size of the phosphorus adsorbent material is 0.8-15 nm.

[0014] Furthermore, the polymer fiber is at least one selected from polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl alcohol formaldehyde fiber, and polyvinyl chloride fiber.

[0015] Furthermore, at least some of the amino groups are also bound to non-ferrous transition metal ions.

[0016] Furthermore, the phosphorus adsorbent material is prepared by a method comprising the following steps:

[0017] Porous biomass carbon, polymer fibers, and binders are stirred to obtain a porous composite material precursor; the porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine-containing porous composite material precursor; the amine-containing porous composite material precursor is mixed with an iron salt and subjected to a hydrothermal reaction at 90-130℃ for 2-6 hours to obtain the phosphorus adsorbent material.

[0018] Secondly, this application provides a method for preparing the above-mentioned phosphorus adsorbent material, comprising the following steps:

[0019] 1) Porous biomass carbon, polymer fibers and binders are stirred to obtain a porous composite material precursor;

[0020] 2) The porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine-containing porous composite material precursor;

[0021] 3) Mix the amine-containing porous composite material precursor and iron salt, and optionally, add a non-ferrous transition metal salt during mixing to obtain a mixture. Perform a hydrothermal reaction at 90-130℃ for 2-6 hours to obtain the phosphorus adsorption material.

[0022] Furthermore, the porous biomass carbon is prepared by a method comprising the following process:

[0023] The biomass material is heated to 500-1600℃ in a protective atmosphere at a heating rate of 1-20℃ / min and held at that temperature for 0.1-12h. The resulting solid product is then washed with acid to obtain the porous biomass carbon.

[0024] Further, in step 1), the mass ratio of the porous biomass carbon, polymer fiber, and binder is 40-90:5-40:5-20;

[0025] And / or, in step 2), the mass ratio of the porous composite material precursor to the amine complexing agent is 1:1-5;

[0026] And / or, in the mixture, the molar ratio of amine groups, iron ions and non-ferrous transition metal ions is 0.6-2.6:1:0-1.2.

[0027] Thirdly, this application provides a method for preparing a positive electrode material, wherein at least part of the raw materials for preparing the positive electrode material are obtained by adsorbing phosphorus adsorbent from phosphorus-containing wastewater.

[0028] Furthermore, the preparation method includes the following steps:

[0029] S1. The phosphorus adsorbent material described in the first aspect is added to phosphorus-containing wastewater, and after adsorption, a phosphorus-rich phosphorus adsorbent material is obtained.

[0030] S2. Elute the phosphorus-rich phosphorus adsorbent material with acid to obtain an eluent and a primary phosphorus adsorbent material; wherein, if the phosphorus concentration in the eluent is ≥5 mmol / L, proceed to step S3, otherwise repeat steps S2-1 and S2 in sequence.

[0031] S2-1. The primary phosphorus adsorbent material and iron salt are mixed to obtain a mixture. Optionally, a non-ferrous transition metal salt is added to the mixture. The mixture is subjected to a hydrothermal reaction at 90-130℃ for 2-6 hours. The obtained phosphorus adsorbent material is added to phosphorus-containing wastewater for adsorption to obtain a phosphorus-rich phosphorus adsorbent material.

[0032] S3. Adjust the molar ratio of metal element to phosphorus element in the eluent to 0.96-1.1, add surfactant and precipitant, and ensure that the pH of the mixed system is ≤1.6 to obtain the first precursor. The chemical composition of the first precursor is M. x Fe 1- x PO4·nH2O, where M is a non-ferrous transition metal, 0≤x≤0.6, n>0;

[0033] S4. After ball milling or grinding the lithium source and the first precursor, a second precursor is obtained; the second precursor and bio-oil are mixed, and the mixture is heated to 500-800℃ in a protective atmosphere at a heating rate of 1-10℃ / min and held for 2-12h to prepare the cathode material.

[0034] The phosphorus adsorbent material provided in this application has a high theoretical adsorption capacity for phosphorus-containing water bodies with both high and low phosphorus concentrations. Moreover, the phosphorus adsorbent material has high mechanical strength, good chemical stability, and can be regenerated and reused multiple times. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 is a SEM image of the phosphorus adsorbent material prepared in Example 1;

[0037] Figure 2 shows the XRD pattern of the phosphorus adsorbent material prepared in Example 1;

[0038] Figure 3 is a SEM image of the cathode material prepared in Example 7.

[0039] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] In a first aspect, this application provides a phosphorus adsorption material, comprising a porous composite material, wherein the porous composite material comprises porous biomass carbon and polymer fibers at least partially wrapped around the porous biomass carbon; the porous composite material contains a plurality of amine groups, and at least some of the amine groups are bonded to iron ions;

[0042] Furthermore, the phosphorus adsorbent material satisfies the following equations 1 to 4: 0.36nm≤d 002 ≤0.43nm Equation 1 0.85≤I D / I G ≤1.38 Equation 2; B≥240 m 2 / g Formula 3; 0.20cm 3 / g≤V≤0.56cm 3 / g Formula 4;

[0043] Where, d 002 Indicates the interlayer spacing of graphite-like microcrystals in phosphorus adsorption materials; I D This indicates that the phosphorus adsorbent material shifts at 1300 cm⁻¹ during Raman spectroscopy testing. -1 Up to 1400cm -1 Peak intensity within the range, I G This indicates that the phosphorus adsorbent material shifts at 1550 cm⁻¹ during Raman spectroscopy testing. -1 Up to 1650cm -1 The peak intensity within the range; B is the specific surface area of ​​the phosphorus adsorbent material, and V is the total pore volume of the phosphorus adsorbent material.

[0044] In this application, porous biomass carbon and polymer fibers are combined to form a porous composite material. This composite material can increase the number of active sites, mechanical strength, and chemical stability of the phosphorus adsorption material, thereby enhancing its phosphorus adsorption capacity and avoiding material loss during long-term use. It also facilitates the regeneration and reuse of the phosphorus adsorption material. Specifically, when the specific surface area and total pore volume of the phosphorus adsorption material meet the conditions of Equation 3-4, it can provide more space to accommodate more phosphorus. When the phosphorus adsorption material meets Equation 1-2, it can form suitable surface defects and graphite-like microcrystalline interlayer spacing. This not only provides more phosphorus-accommodating sites but also provides a large number of amine and iron ion binding sites, which helps more iron ions to bind with amine groups and anchor to the surface of the porous composite material, thereby improving the phosphorus adsorption capacity of the phosphorus adsorption material.

[0045] In detail: The phosphorus adsorption capacity and adsorption mechanism of the phosphorus adsorption material of this application include: ① complexation reaction of iron ions and phosphate ions; ② electrostatic adsorption of porous biomass carbon and amine groups; ③ synergistic effect among porous biomass carbon, polymer fibers, amine groups and iron ions to further enhance the material's coordination binding, electrostatic adsorption and charge transport capabilities.

[0046] It is understandable that the interlayer spacing of graphite-like microcrystals in phosphorus adsorption materials can be directly determined by wide-angle powder XRD; the specific surface area and total pore volume can be determined by a fully automated specific surface area and porosity analyzer.

[0047] In one specific embodiment, when the phosphorus (phosphorus element) concentration in the water is 0.5 mg / L, the theoretical adsorption capacity of the phosphorus adsorbent material for phosphorus is not less than 0.4 mg / g;

[0048] When the phosphorus concentration in the water is 100 mg / L, the theoretical adsorption capacity of the phosphorus adsorbent material is not less than 50 mg / g.

[0049] It should be noted that the iron ions mentioned in this application all refer to ferric ions, and the above-mentioned phosphorus adsorption materials are not limited to water bodies with phosphate concentrations of 0.5-100 mg / L. That is, the phosphorus adsorption materials of this application have a high phosphorus adsorption capacity for various actual phosphorus-containing wastewaters with high and low phosphorus concentrations.

[0050] In one specific embodiment, the average pore size of the phosphorus adsorbent material is 0.8-15 nm.

[0051] In one specific embodiment, the polymer fiber is at least one selected from polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl alcohol formaldehyde fiber, and polyvinyl chloride fiber.

[0052] Furthermore, the polymer fiber is preferably polyester fiber. Polyester fiber is prone to group substitution reaction and bonding with amine groups. Therefore, the porous composite material containing polyester fiber can have more amine groups, thereby allowing more iron ions and non-ferrous transition metal ions to bond with amine groups and anchor on the surface of the porous composite material.

[0053] In one specific embodiment, at least a portion of the amine group is also bound to a non-ferrous transition metal ion.

[0054] For example, the non-ferrous transition metal ion is selected from at least one of manganese ion, vanadium ion, molybdenum ion, chromium ion, titanium ion, and zirconium ion.

[0055] In one specific embodiment, the phosphorus adsorbent material is prepared by a method comprising the following processes:

[0056] Porous biomass carbon, polymer fibers, and binders are stirred to obtain a porous composite material precursor; the porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine-containing porous composite material precursor; the amine-containing porous composite material precursor is mixed with an iron salt and subjected to a hydrothermal reaction at 90-130℃ for 2-6 hours to obtain the phosphorus adsorbent material.

[0057] Secondly, this application provides a method for preparing the above-mentioned phosphorus adsorbent material, comprising the following steps:

[0058] 1) Porous biomass carbon, polymer fibers and binders are stirred to obtain a porous composite material precursor;

[0059] 2) The porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine-containing porous composite material precursor;

[0060] 3) Mix the amine-containing porous composite material precursor and iron salt, and optionally, add a non-ferrous transition metal salt during mixing to obtain a mixture. Perform a hydrothermal reaction at 90-130℃ for 2-6 hours to obtain the phosphorus adsorption material.

[0061] Optionally, after the stirring process in step 1) above, a molding process can be performed. If molding is performed, the phosphorus adsorbent material can be made into granules or rods. The molding process can be injection molding.

[0062] In step 3), the hydrothermal reaction conditions are a crucial factor affecting the adsorption capacity of the phosphorus adsorbent material. If the hydrothermal reaction temperature exceeds 130℃, the reaction rate will be too fast, making the reaction process difficult to control. This will also cause the phosphorus adsorbent material particles to grow larger, their morphology to change, their specific surface area to decrease, and even lead to the collapse of the phosphorus adsorbent material structure, thus affecting the adsorption performance. If the hydrothermal reaction temperature is below 90℃, the mixed liquid material will not react completely, resulting in fewer pores in the phosphorus adsorbent material and poor adsorption performance. If the hydrothermal reaction time is longer than 6 hours, it will cause excessive growth of the phosphorus adsorbent material particles, leading to defects in the particles, irregular morphology, and uneven particle size distribution, thus affecting the adsorption performance. If the hydrothermal reaction time is less than 2 hours, the effects are similar to those caused by excessively low hydrothermal reaction temperatures.

[0063] In one specific embodiment, the porous biomass carbon is prepared by a method comprising the following process:

[0064] The biomass material is heated to 500-1600℃ in a protective atmosphere at a heating rate of 1-20℃ / min and held at that temperature for 0.1-12h. The resulting solid product is then washed with acid to prepare the porous biomass carbon.

[0065] Furthermore, the acid washing of solid products also includes repeated washing with ethanol and deionized water, followed by drying and sieving.

[0066] Furthermore, in order to obtain porous biomass carbon with more pores, the biomass material is heated to 600-900°C in a protective atmosphere at a heating rate of 5°C / min and held at that temperature for 1-3 hours.

[0067] For example, the above-mentioned biomass materials can be selected from at least one of straw, rice husks, livestock and poultry manure, cyanobacteria, sugar residue, distiller's grains, fungal residue, traditional Chinese medicine residue, sludge, starch, chitosan, etc.

[0068] For example, the binder can be selected from carboxymethyl cellulose, polyvinylidene fluoride, styrene-butadiene rubber, epoxy resin binder, polyurethane binder, biomass binder, etc.; preferably, in order to reduce the clogging of the pore structure by the binder, the proportion of the binder in the porous composite material is 5%-20%.

[0069] For example, in step 2), the amine complexing agent may be selected from at least one of amine derivatives containing ammonium salts, urea, proteins, amino acids, etc.

[0070] For example, in step 3), the temperature of the amination reaction is not specifically limited in this application. In order to accelerate the reaction rate, the amination reaction is preferably carried out under heating conditions of 80-120°C.

[0071] For example, step 3) also includes washing and drying the phosphorus adsorbent material with deionized water and ethanol after the reaction is completed.

[0072] In one specific embodiment, in step 1), the mass ratio of the porous biomass carbon, polymer fiber, and binder is 40-90:5-40:5-20;

[0073] And / or, in step 2), the mass ratio of the porous composite material precursor to the amine complexing agent is 1:1-5;

[0074] And / or, in the mixture of step 3), the molar ratio of amino groups, iron ions and non-ferrous transition metal ions is 0.6-2.6:1:0-1.2.

[0075] Thirdly, this application provides a method for preparing a positive electrode material, wherein at least a portion of the raw materials for preparing the positive electrode material are obtained by adsorbing phosphorus adsorbent from phosphorus-containing wastewater.

[0076] In one specific embodiment, the method includes the following steps:

[0077] S1. The phosphorus adsorbent material of the first aspect is added to phosphorus-containing wastewater, and after adsorption, a phosphorus-rich phosphorus adsorbent material is obtained.

[0078] S2. Elute the phosphorus-rich phosphorus adsorbent material with acid to obtain an eluent and a primary phosphorus adsorbent material; wherein, if the phosphorus concentration in the eluent is ≥5 mmol / L, proceed to step S3, otherwise repeat steps S2-1 and S2 in sequence.

[0079] S2-1. The primary phosphorus adsorbent material and iron salt are mixed to obtain a mixture. Optionally, a non-ferrous transition metal salt is added to the mixture. The mixture is subjected to a hydrothermal reaction at 90-130℃ for 2-6 hours. The obtained phosphorus adsorbent material is added to phosphorus-containing wastewater for adsorption to obtain a phosphorus-rich phosphorus adsorbent material.

[0080] S3. Adjust the molar ratio of metal element to phosphorus element in the eluent to 0.96-1.1, add surfactant and precipitant, and ensure that the pH of the mixed system is ≤1.6 to obtain the first precursor. The chemical composition of the first precursor is M. x Fe 1- x PO4·nH2O, where M is a non-ferrous transition metal, 0≤x≤0.6, n>0;

[0081] S4. After ball milling or grinding the lithium source and the first precursor, a second precursor is obtained; the second precursor and bio-oil are mixed, and the mixture is heated to 500-800℃ in a protective atmosphere at a heating rate of 1-10℃ / min and held for 2-12h to prepare the cathode material.

[0082] In the above preparation method, the use of surfactants can obtain a first precursor with relatively uniform particles and a relatively regular and uniform morphology. This material is helpful in preparing cathode materials with excellent conductivity. In addition, the above preparation method uses bio-oil as a carbon source in the preparation of cathode materials, which can play a reduction role, allowing Fe... 3+ Reduced to Fe 2+ On the other hand, it can also form a uniform and thin layer of coated carbon on the surface of the cathode material, improve the ion transport and charge conduction capabilities of the material, and enhance the chemical stability and mechanical strength of the material.

[0083] The non-ferrous transition metal salt is M x Fe 1-x The source of PO4·nH2O material can be determined by the technician, who can adjust the type of non-ferrous transition metal salt according to the type of cathode material required. Preferably, the non-ferrous transition metal salt is a manganese salt.

[0084] For example, the phosphorus-containing wastewater involved in this application can be any one of biogas slurry, aquaculture wastewater, brewing wastewater, domestic sewage, municipal tailwater, phosphate fertilizer production wastewater, slaughterhouse wastewater, meat product processing wastewater, etc.

[0085] For example, in step S3, the molar ratio of iron, non-ferrous transition metals and phosphorus in the eluent can be adjusted by supplementing or diluting the concentration of iron ions and non-ferrous transition metal ions.

[0086] For example, in step S1 or S2-1, the dosage of phosphorus adsorbent material is 1:5-1:20 g / L, and the adsorption time is 0.2-2 h.

[0087] In one specific embodiment, the acid washing in step S2 is preferably performed using an acid solution with a pH not higher than 1.5, and the washing time is 0.1-2 hours. Wherein, M x Fe 1-x The pH at which PO4·nH2O completely precipitates is no higher than 1.5, and the washing time is mainly to ensure that phosphate, iron, and manganese ions can be removed at M... x Fe 1-x The molecular form of PO4·nH2O is completely desorbed from the phosphorus adsorbent. If the pH is higher than 1.5, some phosphate, iron, and manganese ions will precipitate in other molecular forms, leading to the precipitation of the target product M. x Fe 1-xPO4·nH2O may contain other impurities. If the washing time is less than 0.1 h, the above components cannot be completely desorbed and precipitated, and the target product M will not be obtained. x Fe 1-x If PO4·nH2O is insufficient and the time exceeds 2 hours, product M will be affected. x Fe 1-x The physicochemical properties and morphology of PO4·nH2O may change, affecting its performance.

[0088] In one specific embodiment, the bio-oil and the second precursor have a mass ratio of 5%-20%.

[0089] In one specific embodiment, a surfactant is added to the mixture at 1%-5% of the mass of the phosphate.

[0090] For example, before adding the surfactant, an oxidant is also added; the oxidant can be selected from hydrogen peroxide, etc. Furthermore, after adding the oxidant for oxidation, the mixed solution can be heated to 60-100°C and reacted for 0.5-2 hours to completely decompose the hydrogen peroxide. Then, the mixed solution is heated further while adding the surfactant.

[0091] For example, the surfactant mentioned above is any one of cetyltrimethylammonium bromide, cis-oleoyl primary amine, ascorbic acid, etc.

[0092] For example, the precipitant can be selected from sodium hydroxide or ammonia.

[0093] For example, after the reaction in step S3, the generated precipitate is repeatedly washed with deionized water and ethanol and then vacuum dried. After that, an appropriate amount of deionized water is added to the vacuum-dried solid particles, and spray drying is carried out at 140-260°C to finally obtain the first precursor.

[0094] For example, the lithium source can be selected from any one of lithium carbonate, lithium phosphate, lithium hydroxide, lithium oxalate, lithium acetate, lithium nitrate, lithium chloride, and lithium sulfate.

[0095] In one specific embodiment, the bio-oil is obtained by a method comprising the following processes:

[0096] Crude bio-oil is prepared by heating biomass materials to 500-1600℃ in a protective atmosphere at a heating rate of 1-20℃ / min and holding at that temperature for 0.1-12h. The crude bio-oil is then washed, distilled, and dried to obtain the bio-oil.

[0097] In the above embodiments, bio-oil is a liquid product in the biomass carbon preparation process, and it has a lower cost compared with commonly used carbon sources such as sucrose and glucose.

[0098] In one specific embodiment, the chemical composition of the above-mentioned cathode material is LiMn. x Fe 1-x PO4 / C, where x is 0-0.6, is a positive electrode material that can be used to assemble batteries. In one specific embodiment, the following steps are included:

[0099] (1) Prepare a positive electrode sheet by combining positive electrode material, binder, conductive agent and aluminum foil;

[0100] (2) Prepare a negative electrode sheet by using biomass carbon, binder, conductive agent and copper foil generated during the bio-oil preparation process.

[0101] (3) Assemble the above positive electrode, negative electrode, separator, electrolyte and battery case into a lithium-ion button battery.

[0102] The present application is described in detail below with reference to specific embodiments:

[0103] The polyester fiber used in the following experiments was PET600-600MS, Φ7mm;

[0104] Carboxymethyl cellulose CAS No.: 9000-11-7.

[0105] Example 1

[0106] This example provides a phosphorus adsorbent material, comprising a porous composite material, wherein the porous composite material includes porous biomass carbon and polymer fibers at least partially wrapped around the porous biomass carbon; the porous composite material contains a plurality of amine groups, and at least a portion of the amine groups are bonded to iron ions; the phosphorus adsorbent material satisfies: d 002 =0.418nm, I D / I G =1.31, specific surface area =356.8m² 2 / g, total pore volume = 0.43cm³ 3 / g, average pore size = 10.4nm. Among them, Figure 1 is the SEM image of the phosphorus adsorbent material in this example, and Figure 2 is the XRD image of the phosphorus adsorbent material in this example.

[0107] Its preparation method includes the following steps:

[0108] 1) The straw was heated to 600℃ in an argon atmosphere at a heating rate of 5℃ / min and kept at that temperature for 2h. The obtained solid product was repeatedly washed with hydrochloric acid, ethanol and deionized water, dried and sieved to prepare the porous biomass carbon.

[0109] 2) Porous biomass carbon, polyester fiber and carboxymethyl cellulose are mixed in a mass ratio of 75:15:10. The mixture is heated and injection molded to obtain a rod-shaped porous composite material.

[0110] 3) The 10g porous composite material was subjected to an amination reaction with 60mL of 40% urea solution at 100℃, and then washed and dried to obtain the NH2-porous composite material.

[0111] 4) Mix the NH2- porous composite material, 0.5 mol / L ferric chloride solution, and 0.5 mol / L manganese chloride solution to obtain a mixed liquid material (the molar ratio of amino groups, iron ions, and transition metal ions is 1.35:1:0.4). Perform a hydrothermal reaction at 110℃ for 4 h. After the reaction is completed, the hydrothermal solid product is washed with deionized water and ethanol and dried to obtain the phosphorus adsorption material.

[0112] Example 2

[0113] Same as Example 1, except that the polyester fiber is replaced with polyamide fiber, and the phosphorus adsorbent material satisfies: d 002 =0.41nm, I D / I G =1.28, specific surface area =426.5m² 2 / g, total pore volume = 0.47cm³ 3 / g, average particle size = 11.2nm.

[0114] Example 3

[0115] Same as Example 1, except that the hydrothermal reaction was carried out at 130°C for 6 hours, and the phosphorus adsorbent material satisfies: d 002 =0.425nm, I D / I G =1.36, specific surface area =553.9m² 2 / g, total pore volume = 0.55cm³ 3 / g, average pore size = 14.4nm.

[0116] Example 4

[0117] Same as Example 1, except that porous biomass carbon, polyester fiber, and carboxymethyl cellulose are mixed in a mass ratio of 70:10:20. This phosphorus adsorbent material satisfies: d 002 =0.386nm, I D / I G =0.96, specific surface area =242.1m² 2 / g, total pore volume = 0.29cm³ 3 / g, average particle size = 8.7nm.

[0118] Example 5

[0119] Same as Example 1, except that no manganese chloride solution is added.

[0120] Example 6

[0121] Same as Example 1, except that the porous biomass carbon preparation steps are as follows: rice husks are heated to 900°C in a nitrogen atmosphere at a heating rate of 10°C / min, and held at that temperature for 3 hours. The obtained solid product is repeatedly washed with hydrochloric acid, ethanol, and deionized water, dried, and sieved to prepare the porous biomass carbon; this phosphorus adsorbent material satisfies: d 002 =0.405nm, I D / I G =1.17, specific surface area =286.1m² 2 / g, total pore volume = 0.37cm³ 3 / g, average pore size = 9.4nm.

[0122] Comparative Example 1

[0123] Same as Example 1, except that porous biomass carbon is not included.

[0124] Performance Test 1:

[0125] 1) The adsorption properties of the phosphorus adsorbent material were tested, and the results are summarized in Table 1.

[0126] The adsorption capacity test method is as follows: Prepare 2L of each of a series of phosphorus concentrations of 0.5, 1, 2, 5, 10, 50, and 100 mg / L. Add 2g of the phosphorus adsorption material from the examples and comparative examples to each of the above solutions. Shake at 25°C for 2 hours to adsorb phosphorus from the solution. Then, take the supernatant and determine the phosphorus content. Calculate the phosphorus adsorption capacity of the phosphorus adsorption material according to the following formula:

[0127] In the formula:

[0128] Q represents the phosphorus adsorption capacity of the phosphorus adsorption material, in mg / g.

[0129] C0 represents the initial phosphorus concentration in the solution, in mg / L.

[0130] C e The phosphorus concentration in the solution after the adsorption reaction is expressed in mg / L.

[0131] V is the volume of the solution, in L;

[0132] m represents the amount of phosphorus adsorbent added, in grams.

[0133] Table 1. Results of phosphorus adsorption performance tests

[0134] As shown in Table 1, compared with the comparative example, the phosphorus adsorbent material prepared in the examples has a higher adsorption capacity for phosphorus in phosphorus-containing water bodies with both high phosphorus concentration (100 mg / L) and low phosphorus concentration (0.5 mg / L); in particular, the phosphorus adsorbent material of Example 1 has better phosphorus adsorption performance.

[0135] 2) The phosphorus adsorption capacity and regeneration efficiency of the phosphorus adsorbent material were tested, and the results are summarized in Table 2:

[0136] Test method: Weigh 2g of the phosphorus adsorbent material obtained in Example 1 and tested for phosphorus adsorption capacity, and elute it with 75mL of sulfuric acid solution (pH=1) for 20min. Then, mix the eluted phosphorus adsorbent material with 0.5mol / L ferric chloride solution and 0.5mol / L manganese chloride solution to obtain a mixed liquid material. Then, carry out a hydrothermal reaction at 110℃ for 4h. After the reaction is completed, wash the hydrothermal solid product with deionized water and ethanol and dry it to obtain the regenerated phosphorus adsorbent material. Then, test the phosphorus adsorption capacity of the regenerated phosphorus adsorbent material in 100mg / L phosphorus standard solution, and refer to step 1) for the test method. Repeat the above steps 5 times to obtain the phosphorus adsorption capacity and regeneration efficiency of the regenerated phosphorus adsorbent material. The results are shown in Table 2.

[0137] Table 2 Phosphorus adsorption capacity and regeneration efficiency of regenerated phosphorus adsorbent materials

[0138] As shown in Table 2, the phosphorus adsorbent material of this application has excellent regeneration ability and can be recycled multiple times.

[0139] Example 7

[0140] This example provides a method for preparing a cathode material, including the following steps:

[0141] S1. Add 10g of the phosphorus adsorbent material from Example 1 to 1000mL of phosphorus-containing wastewater (biogas slurry, phosphorus concentration of 46.3mg / L), and after adsorption for 1h, separate the solid and liquid to obtain phosphorus-rich phosphorus adsorbent material.

[0142] S2. Elute the phosphorus-rich phosphorus adsorbent material with a sulfuric acid solution at pH 1.5 to obtain an eluent and a primary phosphorus adsorbent material; wherein, if the concentration of phosphate in the eluent is ≥5 mmol / L, proceed to step S3, otherwise repeat steps S2-1 and S2 in sequence.

[0143] S2-1. The mixed liquid material of the primary phosphorus adsorbent, ferric chloride, and manganese chloride is subjected to hydrothermal reaction at 120°C for 3 hours. The obtained phosphorus adsorbent is added to phosphorus-containing wastewater for adsorption. After the reaction is completed, the hydrothermal solid product is washed with deionized water and ethanol and dried to obtain phosphorus-rich phosphorus adsorbent again.

[0144] S3. Adjust the molar ratio of Fe and Mn to P in the eluent to 0.96-1.1. Then add a small amount of hydrogen peroxide solution to the eluent to ensure Fe... 2+ All were oxidized to Fe 3+ The mixed solution was then heated to 60°C and reacted for 2 hours to allow complete decomposition of hydrogen peroxide. Heating continued, and simultaneously, 2% (by mass of phosphate) of the surfactant cetyltrimethylammonium bromide was added. Sodium hydroxide, a precipitant, was then added to maintain a pH ≤ 1.6. After reacting for 12 hours, the first precursor, Mn, was obtained. 0.4 Fe 0.6 PO4·nH2O, n>0;

[0145] S4. Straw biomass material was heated to 800℃ in an argon atmosphere at a heating rate of 5℃ / min and held at that temperature for 2h. The obtained solid product was repeatedly washed with hydrochloric acid, ethanol, and deionized water, dried, and sieved to prepare bio-oil and porous biomass carbon. 5g of bio-oil was dissolved in 50mL of ethanol at 80℃ to obtain a mixed solution.

[0146] S5, lithium carbonate and the Mn 0.4 Fe 0.6 PO4·nH2O was mixed uniformly at a molar ratio of (1.1-1):1, a small amount of deionized water was added, and the mixture was ball-milled and dried to obtain a second precursor. The second precursor was mixed with a mixture containing bio-oil (the mass ratio of bio-oil to precursor was 5%), and the mixture was heated to 650℃ at a heating rate of 5℃ / min in an argon atmosphere and held for 6 h to prepare the cathode material LiMn. 0.4 Fe 0.6 PO4 / C, where Figure 3 shows the LiMn cathode material in this example. 0.4 Fe 0.6 SEM image of PO4 / C.

[0147] Example 8

[0148] The difference from Example 5 is that, in S5, the mass ratio of bio-oil to the second precursor is 20%.

[0149] Example 9

[0150] The difference from Example 5 is that S5 bio-oil is replaced with sucrose.

[0151] Performance Test 2:

[0152] The electrochemical performance of the cathode material was tested, and the results are summarized in Table 3.

[0153] The process of assembling the positive electrode materials of Examples 7-9 into a positive electrode sheet is as follows: The positive electrode material LiMn... x Fe 1-x PO4 / C, acetylene black, and polyvinylidene fluoride were dissolved in N-methylpyrrolidone at a mass ratio of 8:1:1 and stirred to form a slurry. The slurry was then coated onto the surface of aluminum foil using a spatula. The positive electrode was subsequently dried at 80°C for 4 hours, followed by vacuum drying at 120°C for 12 hours. Afterward, it was pressed and cut using a tablet press to obtain the positive electrode.

[0154] The positive electrode is assembled into a battery as follows: Inside a glove box, ensuring both moisture and oxygen content do not exceed 0.1 ppm, the positive electrode is placed in the center of the positive electrode shell. Next, the positive electrode is soaked in electrolyte (1 mol / L LiPF6 dissolved in a 1:1 volume ratio of EC and DEC). Then, the Celgard separator is placed on top of the positive electrode, and the separator is soaked in electrolyte. The lithium sheet is then placed in the center of the separator. A gasket and spring are then placed on top of the lithium sheet, and finally, the negative electrode shell is covered. Finally, the battery is pressed at 10 MPa using a battery sealing machine to obtain the finished button cell battery.

[0155] Battery performance was tested using constant current charge-discharge tests to evaluate specific capacity, rate performance, and cycle performance. The charge / discharge voltage ranged from 2.0 to 4.5V, and the current densities were set at 0.2C, 1C, and 5C (1C = 170 mA / g). The results are shown in Table 3.

[0156] Table 3. Test results of cathode material performance

[0157] As shown in Table 3, the cathode materials prepared in Examples 7-9, when used to assemble batteries, exhibit high specific capacity, high rate performance, and excellent cycle performance.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A phosphorus adsorbing material, characterized by, The porous composite material comprises porous biomass carbon and high molecular fiber at least partially wrapping the porous biomass carbon; the porous composite material comprises a plurality of amine groups, and at least part of the amine groups are combined with iron ions; The phosphorus adsorption material satisfies the following formula 1 to formula 4: 0.36 nm < d 002 ≤0.43 nm Equation 1; 0.85 < I D / I G ≤ 1.38 Equation 2; B ≥ 240 m 2 / g Formula 3; 0.20 cm 3 / g ≤ V ≤ 0.56 cm 3 / g Equation 4; wherein d 002 represents the interlayer spacing of the graphite-like microcrystalline layer in the phosphorus adsorption material; I D represents the peak intensity of the phosphorus adsorption material in the range of 1300 cm -1 to 1400 cm -1 when tested by Raman spectroscopy; I G represents the peak intensity of the phosphorus adsorption material in the range of 1550 cm -1 to 1650 cm -1 when tested by Raman spectroscopy; B is the specific surface area of the phosphorus adsorption material, and V is the total pore volume of the phosphorus adsorption material.

2. The phosphorus adsorption material according to claim 1, characterized by, The average pore size of the phosphorus adsorption material is 0.8-15 nm.

3. The phosphorus adsorption material according to claim 1, wherein The high molecular fiber is at least one of polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl formal fiber and polyvinyl chloride fiber.

4. The phosphorus adsorption material according to claim 1, wherein At least part of the amine groups are also combined with non-iron transition metal ions.

5. The phosphorus adsorbing material according to any one of claims 1 to 4, characterized by The porous composite material is prepared by a method comprising the following steps: The porous biomass carbon, the high molecular fiber and the binder are subjected to stirring treatment to obtain a porous composite material precursor; the porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine group-containing porous composite material precursor; and the amine group-containing porous composite material precursor is subjected to a hydrothermal reaction with a mixture of an iron salt at 90-130 ℃ for 2-6 h to obtain the phosphorus adsorption material.

6. A method for producing the phosphorus adsorbing material according to any one of claims 1 to 5, characterized by, The method comprises the following steps: 1) The porous biomass carbon, the high molecular fiber and the binder are subjected to stirring treatment to obtain a porous composite material precursor; 2) The porous composite material precursor is subjected to an amination reaction with an amine complexing agent to obtain an amine group-containing porous composite material precursor; 3) The amine group-containing porous composite material precursor and an iron salt solution are mixed, and optionally, a non-iron transition metal salt is added during the mixing to obtain a mixture, which is subjected to a hydrothermal reaction at 90-130 ℃ for 2-6 h to obtain the phosphorus adsorption material.

7. The production method according to claim 6, characterized by, The porous biomass carbon is prepared by a method comprising the following steps: The biomass material is heated to 500-1600 ℃ at a heating rate of 1-20 ℃ / min in a protective atmosphere, and the obtained solid product is cleaned with an acid to obtain the porous biomass carbon.

8. The production method according to claim 6 or 7, characterized by, In step 1), the mass ratio of the porous biomass carbon, the high molecular fiber and the binder is 40-90:5-40:5-20; In step 2), the mass ratio of the porous composite material precursor and the amine complexing agent is 1:1-5; In the mixture, the molar ratio of the amine group, the iron ion and the non-iron transition metal ion is 0.6-2.6:1:0-1.

2.

9. A method for producing a positive electrode material, characterized by, At least part of the raw materials for preparing the positive electrode material are obtained by adsorption of the phosphorus adsorption material from the phosphorus-containing wastewater.

10. The method of claim 9, wherein, The method comprises the following steps: S1. The phosphorus adsorption material is added into the phosphorus-containing wastewater, and after adsorption, a phosphorus-rich phosphorus adsorption material is obtained; S2. The phosphorus-rich phosphorus adsorption material is eluted with an acid solution to obtain an eluate and a primary phosphorus adsorption material; if the concentration of phosphorus in the eluate is ≥5 mmol / L, step S3 is performed, otherwise, steps S2-1 and S2 are repeatedly performed in sequence. S2-1, the phosphorus adsorption material and the iron salt are mixed to obtain a mixture, optionally, the mixture further comprises a non-iron transition metal salt; the mixture is subjected to a hydrothermal reaction at 90-130 DEG C for 2-6h to obtain a phosphorus adsorption material; the phosphorus adsorption material is added into the wastewater containing phosphorus, and after adsorption, a phosphorus-rich phosphorus adsorption material is obtained; S3, the molar ratio of the metal element to the phosphorus element in the eluent is 0.96-1.1, a surfactant and a precipitant are added, the pH of the mixed system is ensured to be less than or equal to 1.6, a first precursor is obtained, and the chemical composition of the first precursor is M x Fe 1- x PO4·nH2O, wherein M is a non-iron transition metal, 0≤x≤0.6, and n>0. S4, a lithium source is ball milled or ground with the first precursor to obtain a second precursor; the second precursor and bio-oil are mixed, and the mixed system is heated to 500-800 DEG C at a heating rate of 1-10 DEG C / min in a protective atmosphere, and is kept at the temperature for 2-12h to prepare the positive electrode material.

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