A phosphorus adsorption material and its preparation method and application

Abstract

The present invention provides a phosphorus adsorption material and its preparation method and application. The phosphorus adsorption material comprises a porous composite material, the porous composite material comprises porous biomass carbon and a polymer fiber at least partially wrapped around the porous biomass carbon; the porous composite material comprises a plurality of amine groups, at least some of which are bound to iron ions; and the following conditions are met: 0.36nm≤d 002 ≤0.43nm, 0.85≤I D / I G ≤1.38, B≥240m 2 / g,0.20cm 3 / g≤V≤0.56cm 3 / g, where d 002 represents the interlayer spacing of graphite-like crystallites in the phosphorus adsorbent material; B represents the specific surface area of ​​the phosphorus adsorbent material; and V represents the total pore volume of the phosphorus adsorbent material. The phosphorus adsorbent material provided by the present invention has a high theoretical adsorption capacity for both high and low phosphorus-containing water bodies, and is regenerable and reusable.

Description

Technical Field

[0001] The present invention relates to the field of water treatment, and in particular to a phosphorus adsorption material, a preparation method and an application thereof. Background Art

[0002] With the increase in industrial activities 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.

[0003] Huge quantities of phosphorus enter sewage, and the continuous discharge of large quantities of phosphorus-containing wastewater into aquatic environments accelerates the deterioration of water bodies. If untreated, direct discharge into natural water bodies poses potential threats to the environment and humans, such as eutrophication, indirect or direct mortality of plants and animals, and harm to human health. It also contributes to the loss of phosphorus resources.

[0004] Common treatment technologies for phosphorus-containing wastewater include biological, chemical, and physical methods. Biological methods often utilize microorganisms to convert organic phosphorus compounds into inorganic compounds, and then remove phosphorus through biological adsorption and precipitation. However, these methods require strict control of parameters such as water quality, temperature, and oxygen, and significantly affect indicators such as pH and COD. Chemical methods require the addition of large amounts of chemical reagents, which are costly and require large amounts of reagents, and are prone to secondary pollution. Physical methods primarily utilize physical adsorption, but existing adsorbents have limited adsorption capacity for phosphorus in phosphorus-containing wastewater, especially for low-phosphorus-concentration phosphorus-containing wastewater. Summary of the Invention

[0005] The present invention provides a phosphorus adsorption material, which has a high theoretical adsorption capacity for phosphorus in phosphorus-containing water bodies with high or low phosphorus concentrations, and the phosphorus adsorption material has good chemical stability and can be regenerated and reused.

[0006] The present invention also provides a method for preparing a phosphorus adsorption material, which can prepare the phosphorus adsorption material and has a simple process.

[0007] The present invention also provides a method for preparing a positive electrode material by using the phosphorus adsorption material and phosphorus-containing wastewater. The method can prepare a phosphorus-containing positive electrode material.

[0008] In a first aspect, the present invention provides a porous composite material comprising porous biomass carbon and polymer fibers at least partially entangled with the porous biomass carbon; the porous composite material comprises a plurality of amine groups, at least some of which are bound to iron ions;

[0009] The phosphorus adsorption material satisfies the following formulas 1 to 4:

[0010] 0.36nm≤d002 ≤0.43nm Formula 1;

[0011] 0.85≤I D / I G ≤1.38 Equation 2;

[0012] B≥240 m 2 / g formula 3;

[0013] 0.20cm 3 / g≤V≤0.56cm 3 / g formula 4;

[0014] Among them, d 002 I represents the interlayer spacing of graphite crystallites in the phosphorus adsorption material; D Indicates that the phosphorus adsorption material shifts at 1300cm during Raman spectroscopy testing. -1 to 1400cm -1 Peak intensity within the range, I G Indicates that the phosphorus adsorption material shifts at 1550cm during Raman spectroscopy testing. -1 to 1650cm -1 B is the specific surface area of ​​the phosphorus adsorption material, and V is the total pore volume of the phosphorus adsorption material.

[0015] Furthermore, the average pore size of the phosphorus adsorption material is 0.8-15 nm.

[0016] Furthermore, the polymer fiber is at least one of polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl formal fiber, and polyvinyl chloride fiber.

[0017] Furthermore, at least part of the amino groups are also bound to non-ferrous transition metal ions.

[0018] Furthermore, the phosphorus adsorption material is prepared by a method comprising the following steps:

[0019] The porous biomass carbon, polymer fiber and binder 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 mixture of the amine-containing porous composite material precursor and the iron salt is subjected to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

[0020] In a second aspect, the present invention provides a method for preparing the above-mentioned phosphorus adsorption material, comprising the following steps:

[0021] 1) The porous biomass carbon, polymer fiber and binder are stirred to obtain a porous composite material precursor;

[0022] 2) performing an amination reaction on the porous composite material precursor and an amine complexing agent to obtain an amine-containing porous composite material precursor;

[0023] 3) Mixing the amine-containing porous composite material precursor and the iron salt, optionally adding a non-ferrous transition metal salt during the mixing, to obtain a mixture, and performing a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

[0024] Furthermore, the porous biomass carbon is prepared by a method comprising the following steps:

[0025] The biomass material is heated to 500-1600° C. at a heating rate of 1-20° C. / min in a protective atmosphere and kept warm for 0.1-12 hours. The obtained solid product is washed with acid to obtain the porous biomass carbon.

[0026] Furthermore, in step 1), the mass ratio of the porous biomass carbon, the polymer fiber, and the binder is 40-90:5-40:5-20;

[0027] And / or, in step 2), the mass ratio of the porous composite material precursor to the amine complexing agent is 1:1-5;

[0028] And / or, in the mixed material, the molar ratio of amine group, iron ion and non-ferrous transition metal ion is 0.6-2.6:1:0-1.2.

[0029] In a third aspect, the present invention 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 the phosphorus adsorption material from phosphorus-containing wastewater.

[0030] Furthermore, the preparation method comprises the following steps:

[0031] S1. Adding the phosphorus adsorption material described in the first aspect to phosphorus-containing wastewater to perform adsorption to obtain a phosphorus-rich phosphorus adsorption material;

[0032] S2. Elute the phosphorus-rich phosphorus adsorption material with an acid solution to obtain an eluate and a primary phosphorus adsorption material; if the phosphorus concentration in the eluate is ≥5 mmol / L, proceed to step S3; otherwise, repeat steps S2-1 and S2 in sequence;

[0033] S2-1, mixing the primary phosphorus adsorption material and an iron salt to obtain a mixture, optionally adding a non-ferrous transition metal salt to the mixture; subjecting the mixture to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain a phosphorus adsorption material, adding the phosphorus adsorption material to phosphorus-containing wastewater for adsorption to obtain a phosphorus-rich phosphorus adsorption material;

[0034] S3, adjusting the molar ratio of metal elements to phosphorus elements in the eluent to 0.96-1.1, adding a surfactant and a precipitant to ensure that the pH of the mixed system is ≤1.6, and obtaining a first precursor, wherein 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, and n>0;

[0035] S4. The lithium source and the first precursor are ball-milled or ground to obtain a second precursor; the second precursor is mixed with bio-oil, and the mixed system is heated to 500-800°C at a heating rate of 1-10°C / min in a protective atmosphere and kept warm for 2-12 hours to prepare the positive electrode material.

[0036] The phosphorus adsorption material provided by the present invention has a high theoretical adsorption capacity for phosphorus-containing water bodies with high / low phosphorus concentrations, and the phosphorus adsorption material has high mechanical strength and good chemical stability and can be regenerated and reused multiple times. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0038] Figure 1 This is an SEM image of the phosphorus adsorption material prepared in Example 1;

[0039] Figure 2 This is the XRD pattern of the phosphorus adsorption material prepared in Example 1;

[0040] Figure 3 This is the SEM image of the positive electrode material prepared in Example 7.

[0041] The above drawings illustrate specific embodiments of the present invention, which will be described in more detail below. These drawings and the accompanying description are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the present invention more clear, the following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the application embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the application, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0043] In a first aspect, the present invention 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 comprises a plurality of amine groups, at least some of which are bound to iron ions;

[0044] The phosphorus adsorption material satisfies the following formulas 1 to 4:

[0045] 0.36nm≤d 002 ≤0.43nm Formula 1

[0046] 0.85≤I D / I G ≤1.38 Equation 2;

[0047] B≥240 m 2 / g formula 3;

[0048] 0.20cm 3 / g≤V≤0.56cm 3 / g formula 4;

[0049] Among them, d 002 I represents the interlayer spacing of graphite-like crystallites in phosphorus adsorption materials; D Indicates that the phosphorus adsorption material shifts at 1300cm during Raman spectroscopy testing. -1 to 1400cm -1 Peak intensity within the range, I G Indicates that the phosphorus adsorption material shifts at 1550cm during Raman spectroscopy testing. -1 to 1650cm -1 B is the specific surface area of ​​the phosphorus adsorption material, and V is the total pore volume of the phosphorus adsorption material.

[0050] In the present invention, porous biomass carbon and polymer fibers are combined to form a porous composite material. The composite material can increase the number of active sites, mechanical strength and chemical stability of the phosphorus adsorption material, thereby enhancing the adsorption capacity for phosphorus, avoiding material loss during long-term use, and facilitating the regeneration and reuse of the phosphorus adsorption material. When the specific surface area and total pore volume of the phosphorus adsorption material meet the conditions of formulas 3-4, more space can be provided to accommodate more phosphorus. When the phosphorus adsorption material meets formulas 1-2, the material can form suitable surface defects and graphite-like microcrystalline interlayer spacing, which not only provides more phosphorus accommodating sites, but also provides a large number of amine groups and iron ion binding sites, helping more iron ions to bind to amine groups and anchor to the surface of the porous composite material, thereby improving the phosphorus adsorption capacity of the phosphorus adsorption material.

[0051] In detail: The phosphorus adsorption capacity and adsorption mechanism of the phosphorus adsorption material of the present invention include: ① the complex reaction of iron ions and phosphate groups; ② the electrostatic adsorption effect of porous biomass carbon and amine groups; ③ the synergistic effect between porous biomass carbon, polymer fibers, amine groups, and iron ions further enhances the material's coordination bonding, electrostatic adsorption, and charge transfer capabilities.

[0052] It can be understood that the graphite-like crystallite interlayer spacing in the phosphorus adsorption material can be directly measured by powder XRD wide-angle diffraction method; the specific surface area and total pore volume can be measured by a fully automatic specific surface and porosity analyzer.

[0053] In one embodiment, when the phosphorus (elemental phosphorus) concentration in the water body is 0.5 mg / L, the theoretical adsorption capacity of the phosphorus adsorption material for phosphorus is not less than 0.4 mg / g;

[0054] When the phosphorus concentration in the water body is 100 mg / L, the theoretical phosphorus adsorption capacity of the phosphorus adsorption material is not less than 50 mg / g.

[0055] It should be noted that the iron ions in the present invention refer to trivalent iron ions, and the above-mentioned phosphorus adsorption material is not limited to acting on water bodies with a phosphate concentration of 0.5-100 mg / L. That is, the phosphorus adsorption material of the present invention has a high phosphorus adsorption capacity for various actual phosphorus-containing wastewaters with high and low phosphorus concentrations.

[0056] In one embodiment, the average pore size of the phosphorus adsorption material is 0.8-15 nm.

[0057] In a specific embodiment, the polymer fiber is at least one of polyester fiber, polyamide fiber, polyacrylonitrile fiber, polyvinyl formal fiber, and polyvinyl chloride fiber.

[0058] Furthermore, the polymer fiber is preferably polyester fiber, which easily undergoes group substitution reaction and combines with amino groups. Therefore, the porous composite material containing polyester fiber can have more amino groups, thereby allowing more iron ions and non-ferrous transition metal ions to combine with amino groups and anchor on the surface of the porous composite material.

[0059] In one embodiment, at least some of the amine groups are further bound to non-ferrous transition metal ions.

[0060] Illustratively, 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.

[0061] In one embodiment, the phosphorus adsorption material is prepared by a method comprising the following steps:

[0062] The porous biomass carbon, polymer fiber and binder 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 mixture of the amine-containing porous composite material precursor and the iron salt is subjected to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

[0063] In a second aspect, the present invention provides a method for preparing the above-mentioned phosphorus adsorption material, comprising the following steps:

[0064] 1) The porous biomass carbon, polymer fiber and binder are stirred to obtain a porous composite material precursor;

[0065] 2) performing an amination reaction on the porous composite material precursor and an amine complexing agent to obtain an amine-containing porous composite material precursor;

[0066] 3) Mixing the amine-containing porous composite material precursor and the iron salt, optionally adding a non-ferrous transition metal salt during the mixing, to obtain a mixture, and performing a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

[0067] After the stirring treatment in step 1), a molding treatment may be optionally performed. If the molding treatment is performed, the phosphorus adsorbent material may be formed into a granular or rod-like form. The molding treatment may be injection molding or pressure molding.

[0068] In step 3), the conditions of the hydrothermal reaction are an important factor affecting the adsorption capacity of the phosphorus adsorption material. If the temperature of the hydrothermal reaction is higher than 130°C, the reaction rate will be too fast and the reaction process will be difficult to control. At the same time, the phosphorus adsorption material particles will become larger, the morphology will change, the specific surface area will decrease, and even the structure of the phosphorus adsorption material will collapse, thereby affecting the adsorption performance of the phosphorus adsorption material; if the temperature of the hydrothermal reaction is lower than 90°C, the mixed liquid material fails to react completely, the pore structure of the phosphorus adsorption material is relatively small, resulting in poor adsorption performance of the phosphorus adsorption material; if the hydrothermal reaction time is longer than 6h, the phosphorus adsorption material particles will grow excessively, causing defects in the particles, forming irregular morphology, and uneven particle size distribution, thereby affecting the adsorption performance of the phosphorus adsorption material; if the hydrothermal reaction time is less than 2h, the effect is the same as if the hydrothermal reaction temperature is too low.

[0069] In one embodiment, the porous biomass carbon is prepared by a method comprising the following steps:

[0070] The biomass material is heated to 500-1600° C. at a heating rate of 1-20° C. / min in a protective atmosphere and kept warm for 0.1-12 hours. The obtained solid product is washed with acid to prepare the porous biomass carbon.

[0071] Furthermore, washing the solid product with acid further includes the steps of repeatedly washing with ethanol and deionized water, drying and screening.

[0072] Furthermore, in order to obtain porous biomass carbon with more pores, the biomass material is heated to 600-900° C. at a heating rate of 5° C. / min in a protective atmosphere and kept warm for 1-3 hours.

[0073] Illustratively, the above-mentioned biomass material can be selected from at least one of straw, rice husk, livestock and poultry manure, blue algae, sugar residue, wine lees, fungus residue, traditional Chinese medicine residue, sludge, starch, chitosan, etc.

[0074] Illustratively, the above-mentioned 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 binder accounts for 5%-20% in the porous composite material.

[0075] Illustratively, in step 2), the amine complexing agent can be selected from at least one of amine derivatives such as ammonium salts, urea, proteins, and amino acids.

[0076] For example, in step 3), the temperature of the amination reaction is not particularly limited in the present invention. In order to accelerate the reaction rate, the amination reaction is preferably carried out under heating conditions of 80-120°C.

[0077] Illustratively, step 3) further comprises washing the phosphorus adsorption material with deionized water and ethanol and drying it after the reaction is completed.

[0078] In one embodiment, in step 1), the mass ratio of the porous biomass carbon, the polymer fiber, and the binder is 40-90:5-40:5-20;

[0079] And / or, in step 2), the mass ratio of the porous composite material precursor to the amine complexing agent is 1:1-5;

[0080] And / or, in the mixed material of step 3), the molar ratio of amine group, iron ion and non-ferrous transition metal ion is 0.6-2.6:1:0-1.2.

[0081] In a third aspect, the present invention 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 the phosphorus adsorption material from phosphorus-containing wastewater.

[0082] In one embodiment, the method comprises the following steps:

[0083] S1. Adding the phosphorus adsorption material of the first aspect to phosphorus-containing wastewater to perform adsorption to obtain a phosphorus-rich phosphorus adsorption material;

[0084] S2. Elute the phosphorus-rich phosphorus adsorption material with an acid solution to obtain an eluate and a primary phosphorus adsorption material; if the phosphorus concentration in the eluate is ≥5 mmol / L, proceed to step S3; otherwise, repeat steps S2-1 and S2 in sequence;

[0085] S2-1, mixing the primary phosphorus adsorption material and an iron salt to obtain a mixture, optionally adding a non-ferrous transition metal salt to the mixture; subjecting the mixture to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain a phosphorus adsorption material, adding the phosphorus adsorption material to phosphorus-containing wastewater for adsorption to obtain a phosphorus-rich phosphorus adsorption material;

[0086] S3, adjusting the molar ratio of metal elements to phosphorus elements in the eluent to 0.96-1.1, adding a surfactant and a precipitant to ensure that the pH of the mixed system is ≤1.6, and obtaining a first precursor, wherein 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, and n>0;

[0087] S4. The lithium source and the first precursor are ball-milled or ground to obtain a second precursor; the second precursor is mixed with bio-oil, and the mixed system is heated to 500-800°C at a heating rate of 1-10°C / min in a protective atmosphere and kept warm for 2-12 hours to prepare the positive electrode material.

[0088] In the above preparation method, the use of surfactant can obtain a first precursor with relatively uniform particles and relatively regular and uniform morphology. This material is helpful for preparing a positive electrode material with excellent conductivity. In addition, the above preparation method uses bio-oil as a carbon source when preparing the positive electrode material, which can play a reducing role on the one hand, so that Fe 3+ Reduction to Fe 2+ On the other hand, it can also form a uniform and thin layer of coated carbon on the surface of the positive electrode material, improve the material's ion transport and charge conduction capabilities, and enhance the material's chemical stability and mechanical strength.

[0089] Non-ferrous transition metal salts are M x Fe 1-x Regarding the source of the PO4·nH2O material, technicians can adjust the type of non-ferrous transition metal salt according to the type of the desired positive electrode material. Preferably, the non-ferrous transition metal salt is a manganese salt.

[0090] Illustratively, the phosphorus-containing wastewater involved in the present invention can be any one of biogas slurry, aquaculture wastewater, brewing wastewater, domestic sewage, municipal tail water, phosphate fertilizer production wastewater, slaughtering wastewater, meat product processing wastewater, etc.

[0091] Illustratively, in step S3, the molar ratio of iron, non-ferrous transition metal elements, and phosphorus in the eluent can be adjusted by supplementing or diluting the concentrations of iron ions and non-ferrous transition metal ions.

[0092] Illustratively, in step S1 or S2-1, the dosage of the phosphorus adsorption material is 1:5-1:20 g / L, and the adsorption time is 0.2-2 h.

[0093] In one embodiment, the acid washing in step S2 is preferably carried out with an acid solution having a pH value not higher than 1.5, and the washing time is 0.1-2 hours. x Fe 1-x The pH value for complete precipitation of PO4·nH2O is not higher than 1.5, and the cleaning time is mainly to ensure that phosphate, iron ions and manganese ions can be completely precipitated. x Fe 1-x The molecular form of PO4·nH2O is completely desorbed from the phosphorus adsorption material. If the pH is higher than 1.5, some phosphate, iron ions, and manganese ions will precipitate in other molecular forms, resulting in the target product M x Fe 1-x PO4·nH2O may contain other impurities. If the cleaning time is less than 0.1h, the above components cannot be completely desorbed and precipitated, and the target product M x Fe 1-x If PO4·nH2O is too little and the time is longer than 2h, the product M x Fe 1-x The physicochemical properties and morphology of PO4·nH2O may change, affecting its performance.

[0094] In one embodiment, the mass ratio of the bio-oil to the second precursor is 5%-20%.

[0095] In one embodiment, a surfactant is added to the mixed system in an amount of 1% to 5% by mass of the phosphate.

[0096] Illustratively, before adding the surfactant, an oxidant is also added; the oxidant can be selected from hydrogen peroxide, etc. Further, after adding the oxidant for oxidation, the mixed solution can be heated to 60-100°C and reacted for 0.5-2h to completely decompose the hydrogen peroxide. Thereafter, the mixed solution is continued to be heated while adding the surfactant.

[0097] Illustratively, the surfactant is any one of cetyltrimethylammonium bromide, cis-oleyl primary amine, ascorbic acid, and the like.

[0098] Exemplarily, the precipitant may be selected from sodium hydroxide or aqueous ammonia.

[0099] Illustratively, after the reaction in step S3, the generated precipitate is repeatedly washed with deionized water and ethanol and vacuum-dried, and then an appropriate amount of deionized water is added to the vacuum-dried solid particles, and spray-dried at 140-260° C. to finally obtain the first precursor.

[0100] Illustratively, 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.

[0101] In one embodiment, the bio-oil is produced by a method comprising the following steps:

[0102] The biomass material is heated to 500-1600° C. at a heating rate of 1-20° C. / min in a protective atmosphere and kept warm for 0.1-12 hours to prepare crude bio-oil, which is then cleaned, distilled and dried to obtain the bio-oil.

[0103] In the above embodiment, bio-oil is a liquid product in the process of preparing biomass carbon, and has a lower cost compared with common carbon sources such as sucrose and glucose.

[0104] In one embodiment, the chemical composition of the positive electrode material is LiMn x Fe 1-x PO4 / C, wherein x is 0-0.6, the positive electrode material can be used to assemble a battery. In a specific embodiment, the process comprises the following steps:

[0105] (1) preparing a positive electrode sheet by combining a positive electrode material, a binder, a conductive agent, and an aluminum foil;

[0106] (2) The biomass carbon, binder, conductive agent and copper foil produced in the bio-oil preparation process are prepared into a negative electrode sheet.

[0107] (3) Assemble the above-mentioned positive electrode sheet, negative electrode sheet, separator, electrolyte, and battery shell into a lithium-ion button battery.

[0108] The present invention is described in detail below with reference to specific embodiments:

[0109] The polyester fiber model used in the following experiments is: PET600-600MS, Φ7mm;

[0110] Carboxymethyl cellulose CAS number: 9000-11-7.

[0111] Example 1

[0112] This example provides a phosphorus adsorption material, including 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, at least some of which are bound to iron ions; the phosphorus adsorption material satisfies: d 002 =0.418nm, I D / I G =1.31, specific surface area = 356.8m 2 / g, total pore volume = 0.43 cm 3 / g, average pore size = 10.4nm. Figure 1 This is the SEM image of the phosphorus adsorption material in this example. Figure 2 This is the XRD pattern of the phosphorus adsorption material in this example.

[0113] The preparation method thereof comprises the following steps:

[0114] 1) heating the straw to 600° C. at a heating rate of 5° C. / min in an argon atmosphere and keeping the temperature for 2 h, and repeatedly washing the obtained solid product with hydrochloric acid, ethanol, and deionized water, drying, and sieving to prepare the porous biomass carbon;

[0115] 2) mixing the porous biomass carbon, polyester fiber, and carboxymethyl cellulose in a mass ratio of 75:15:10, heating the mixture and performing injection molding pressure forming to obtain a rod-shaped porous composite material;

[0116] 3) subjecting 10 g of the porous composite material to an amination reaction with 60 mL of a 40% urea solution at 100° C., and washing and drying the resultant to obtain an NH2-porous composite material;

[0117] 4) mixing 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 group, iron ion, and transition metal ion is 1.35:1:0.4), and performing a hydrothermal reaction at 110°C for 4 hours. After the reaction is completed, the hydrothermal solid product is washed with deionized water and ethanol and dried to obtain the phosphorus adsorption material.

[0118] Example 2

[0119] Same as Example 1, except that the polyester fiber is replaced by polyamide fiber. The phosphorus adsorbent material satisfies the following requirements: 002 =0.41nm, I D / I G =1.28, specific surface area = 426.5m 2 / g, total pore volume = 0.47 cm 3 / g, average particle size = 11.2nm.

[0120] Example 3

[0121] Same as Example 1, except that the hydrothermal reaction was carried out at 130°C for 6 hours, and the phosphorus adsorption material met the following requirements: 002 =0.425nm, I D / I G =1.36, specific surface area = 553.9m 2 / g, total pore volume = 0.55 cm 3 / g, average pore diameter = 14.4 nm.

[0122] Example 4

[0123] Same as Example 1, except that porous biomass carbon, polyester fiber and carboxymethyl cellulose are mixed in a mass ratio of 70:10:20. The phosphorus adsorption material satisfies the following requirements: 002 =0.386nm, I D / I G =0.96, specific surface area = 242.1m 2 / g, total pore volume = 0.29 cm 3 / g, average particle size = 8.7nm.

[0124] Example 5

[0125] Same as Example 1, except that no manganese chloride solution was added.

[0126] Example 6

[0127] The same as Example 1, except that the porous biomass carbon preparation steps are as follows: heating the rice husk to 900°C at a heating rate of 10°C / min in a nitrogen atmosphere and keeping the 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; the phosphorus adsorption material satisfies: d 002 =0.405nm, I D / I G =1.17, specific surface area = 286.1m 2 / g, total pore volume = 0.37 cm 3 / g, average pore diameter = 9.4nm.

[0128] Comparative Example 1

[0129] Same as Example 1, except that porous biomass carbon is not included.

[0130] Performance Test 1:

[0131] 1) Adsorption test of phosphorus adsorption materials. The results are summarized in Table 1.

[0132] The adsorption test method is as follows: prepare a series of solutions with phosphorus concentrations of 0.5, 1, 2, 5, 10, 50, and 100 mg / L, 2 L each, add 2 g of the phosphorus adsorption material of the embodiment and the comparative example to the above solutions, and shake at a constant temperature of 25°C for 2 hours to adsorb phosphorus in the solution. Then, take the supernatant to determine the phosphorus content. The phosphorus adsorption capacity of the phosphorus adsorption material is calculated according to the following formula:

[0133]

[0134] Where:

[0135] Q is the phosphorus adsorption capacity of the phosphorus adsorption material, unit: mg / g;

[0136] C0 is the initial phosphorus concentration in the solution, unit: mg / L;

[0137] C e is the phosphorus concentration of the solution after adsorption reaction, unit: mg / L;

[0138] V is the volume of the solution, unit: L;

[0139] m is the amount of phosphorus adsorption material added, unit: g.

[0140] Table 1 Phosphorus adsorption performance test results

[0141]

[0142] As can be seen from Table 1, compared with the comparative example, the phosphorus adsorption material prepared in the embodiment has a higher adsorption capacity for phosphorus, whether in phosphorus-containing water with high phosphorus concentration (100 mg / L) or low phosphorus concentration (0.5 mg / L); in particular, the phosphorus adsorption performance of the phosphorus adsorption material of Example 1 is better.

[0143] 2) Phosphorus adsorption capacity and regeneration efficiency of the phosphorus adsorption material were tested. The results are summarized in Table 2:

[0144] Testing method: 2 g of the phosphorus adsorbent material obtained in Example 1 and tested for phosphorus adsorption performance was weighed and eluted with 75 mL of sulfuric acid solution (pH = 1) for 20 min. The eluted phosphorus adsorbent was then remixed with 0.5 mol / L ferric chloride solution and 0.5 mol / L manganese chloride solution to obtain a mixed liquid material. The mixed liquid material was then hydrothermally reacted at 110°C for 4 h. After the reaction, the hydrothermal solid product was washed with deionized water and ethanol and dried to obtain a regenerated phosphorus adsorbent. The regenerated phosphorus adsorbent was then tested for phosphorus adsorption in a 100 mg / L phosphorus standard solution (see step 1 for the testing method). The above steps were repeated five times to obtain the phosphorus adsorption capacity and regeneration efficiency of the regenerated phosphorus adsorbent. The results are shown in Table 2.

[0145] Table 2 Phosphorus adsorption capacity and regeneration efficiency of regenerated phosphorus adsorption materials

[0146] Regeneration times 0 1 2 3 4 5 Phosphorus adsorption capacity mg / g 78.76 74.66 71.99 75.29 77.26 76.32 Regeneration efficiency% / 94.8 91.4 95.6 98.1 96.9

[0147] As can be seen from Table 2, the phosphorus adsorption material of the present invention has good regeneration ability and can be recycled multiple times.

[0148] Example 7

[0149] This example provides a method for preparing a positive electrode material, comprising the following steps:

[0150] S1. 10 g of the phosphorus adsorption material of Example 1 was added to 1000 mL of phosphorus-containing wastewater (biogas slurry, phosphorus concentration of 46.3 mg / L), and after adsorption for 1 h, the solid and liquid were separated to obtain a phosphorus-rich phosphorus adsorption material;

[0151] S2. Elute the phosphorus-rich phosphorus adsorption material using a sulfuric acid solution with a pH of 1.5 to obtain an eluate and a primary phosphorus adsorption material; if the concentration of phosphate in the eluate is ≥5 mmol / L, proceed to step S3; otherwise, repeat steps S2-1 and S2 in sequence;

[0152] S2-1. A mixed liquid material of the primary phosphorus adsorption material, ferric chloride, and manganese chloride is subjected to a hydrothermal reaction at 120° C. for 3 hours. The obtained phosphorus adsorption material 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 a phosphorus-rich phosphorus adsorption material.

[0153] S3, adjust the molar ratio of the sum of Fe and Mn elements to P in the eluent to 0.96-1.1, then add a small amount of hydrogen peroxide solution to the eluent to ensure that Fe 2+ All oxidized to Fe 3+ The mixed solution was then heated to 60°C and reacted for 2 hours to completely decompose the hydrogen peroxide. The mixed solution was then heated further and a surfactant, hexadecyltrimethylammonium bromide, was added to the mixed solution at a rate of 2% of the mass of the phosphate. The precipitant, sodium hydroxide, was then added to the mixed solution to ensure that the real-time pH of the mixed solution was ≤1.6. After reacting for 12 hours, the first precursor, Mn, was obtained. 0.4 Fe 0.6 PO4·nH2O, n>0;

[0154] S4. The straw biomass material was heated to 800°C at a heating rate of 5°C / min in an argon atmosphere and kept warm for 2 h. 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; 5 g of bio-oil was dissolved in 50 mL of ethanol at 80°C to obtain a mixed solution;

[0155] S5, lithium carbonate and the Mn 0.4 Fe 0.6 PO4·nH2O was mixed uniformly in a mass ratio of (1.1-1):1, a small amount of deionized water was added, ball milled and dried to obtain a second precursor; the second precursor was mixed with a mixed solution containing bio-oil (the mass ratio of bio-oil to precursor was 5%), and the mixture was heated to 650°C at a heating rate of 5°C / min in an argon atmosphere and kept warm for 6 hours to prepare a positive electrode material LiMn 0.4 Fe 0.6 PO4 / C, where Figure 3 The positive electrode material in this example is LiMn 0.4 Fe 0.6 SEM image of PO4 / C.

[0156] Example 8

[0157] The difference from Example 5 is that: S5, the mass ratio of bio-oil to the second precursor is 20%

[0158] Example 9

[0159] The difference from Example 5 is that S5 bio-oil is replaced by sucrose.

[0160] Performance Test 2:

[0161] The electrochemical performance of the cathode materials was tested and the results are summarized in Table 3.

[0162] The positive electrode materials of the above-mentioned embodiments 7-9 are assembled into positive electrode sheets. The process 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 applied to the surface of aluminum foil using a spatula. The positive electrode sheet was then dried at 80°C for 4 hours, followed by vacuum drying at 120°C for 12 hours. The sheet was then pressed and cut using a tablet press to obtain the positive electrode sheet.

[0163] The positive electrode sheet is assembled into a battery. The process is as follows: Inside a glove box, ensuring that both moisture and oxygen levels are no higher than 0.1 ppm, the positive electrode sheet is placed in the center of the positive electrode shell. The positive electrode sheet is then soaked with electrolyte (1 mol / L LiPF6 dissolved in a 1:1 volume ratio of EC and DEC). A Celgard separator is then placed on the positive electrode sheet and soaked with electrolyte. A lithium sheet is then placed in the center of the separator. A gasket and spring are then placed on top of the lithium sheet, followed by the negative electrode shell. Finally, the battery is compacted at 10 MPa using a battery sealer to produce the finished button cell.

[0164] Battery Performance Testing: Constant current charge and discharge tests were used to measure the battery's specific capacity, rate capability, and cycle performance. The charge and discharge voltage ranged from 2.0 to 4.5 V, and the current density was set at 0.2C, 1C, and 5C (1C = 170 mA / g). The results are shown in Table 3.

[0165] Table 3. Test results of cathode material performance

[0166]

[0167] As shown in Table 3, the positive electrode materials prepared in Examples 7-9 are used to assemble batteries and have high specific capacity, rate performance and excellent cycle performance.

[0168] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A phosphorus adsorption material, characterized in that: The porous composite material comprises porous biomass carbon and polymer fibers at least partially wrapped around the porous biomass carbon; the porous composite material comprises a plurality of amine groups, at least some of which are bound to iron ions; The phosphorus adsorption material satisfies the following formulas 1 to 4: 0.36nm≤d 002 ≤0.43nm Formula 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; Among them, d 002 I represents the interlayer spacing of graphite-like crystallites in phosphorus adsorption materials; D Indicates that the phosphorus adsorption material shifts at 1300cm during Raman spectroscopy testing. -1 to 1400cm -1 Peak intensity within the range, I G Indicates that the phosphorus adsorption material shifts at 1550cm during Raman spectroscopy testing. -1 to 1650cm -1 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 in that The average pore size of the phosphorus adsorption material is 0.8-15 nm.

3. The phosphorus adsorption material according to claim 1, characterized in that The polymer 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, characterized in that At least some of the amine groups are also bound to non-ferrous transition metal ions.

5. A phosphorus adsorption material according to any one of claims 1 to 4, characterized in that: Prepared by a method comprising the following steps: The porous biomass carbon, polymer fiber and binder 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 mixture of the amine-containing porous composite material precursor and the iron salt is subjected to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

6. A method for preparing the phosphorus adsorption material according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) The porous biomass carbon, polymer fiber and binder are stirred to obtain a porous composite material precursor; 2) the porous composite material precursor undergoes an amination reaction with an amine complexing agent to obtain an amine-containing porous composite material precursor; 3) Mixing the amine-containing porous composite material precursor and the iron salt solution, optionally adding a non-ferrous transition metal salt during the mixing, to obtain a mixed material, and performing a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain the phosphorus adsorption material.

7. The preparation method according to claim 6, characterized in that The porous biomass carbon is prepared by a method comprising the following steps: The biomass material is heated to 500-1600° C. at a heating rate of 1-20° C. / min in a protective atmosphere and kept warm for 0.1-12 hours. The obtained solid product is washed with acid to obtain the porous biomass carbon.

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

2.

9. A method for preparing a positive electrode material, characterized in that: The following steps are involved: S1. Adding the phosphorus adsorption material according to any one of claims 1 to 5 into phosphorus-containing wastewater to perform adsorption, thereby obtaining a phosphorus-rich phosphorus adsorption material; S2. Elute the phosphorus-rich phosphorus adsorption material with an acid solution to obtain an eluate and a primary phosphorus adsorption material; if the phosphorus concentration in the eluate is ≥5 mmol / L, proceed to step S3; otherwise, repeat steps S2-1 and S2 in sequence; S2-1, mixing the primary phosphorus adsorption material and an iron salt to obtain a mixture, optionally comprising a non-ferrous transition metal salt; subjecting the mixture to a hydrothermal reaction at 90-130° C. for 2-6 hours to obtain a phosphorus adsorption material, adding the phosphorus adsorption material to phosphorus-containing wastewater for adsorption to obtain a phosphorus-rich phosphorus adsorption material; S3, adjusting the molar ratio of metal elements to phosphorus elements in the eluent to 0.96-1.1, adding a surfactant and a precipitant to ensure that the pH of the mixed system is ≤1.6, and obtaining a first precursor, wherein 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, and n>0; S4. The lithium source and the first precursor are ball-milled or ground to obtain a second precursor; the second precursor is mixed with bio-oil, and the mixed system is heated to 500-800°C at a heating rate of 1-10°C / min in a protective atmosphere and kept warm for 2-12 hours to prepare the positive electrode material.

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