Methods and applications of synergistic phosphorus removal using chlorophyll-La derivatives / nano-rare earth-based complexes

Abstract

This application relates to the field of pollutant treatment technology, and provides a method for synergistic phosphorus removal using chlorophyll-La derivatives / nano-rare earth-based complexes and its application. The synergistic phosphorus removal method provided by this application includes: adding a mixture of nano-rare earth-based complexes and chlorophyll-La derivatives to phosphorus-containing pollutants, followed by phototreatment to remove phosphorus; wherein the phosphorus-containing pollutants are selected from phosphorus-containing water bodies or phosphorus-containing soil; the nano-rare earth-based complexes include nano-lanthanum oxide, nano-chitosan, modified calcium and magnesium mineral materials, biochar, zeolite, excipients, and regulators. The synergistic phosphorus removal method using chlorophyll-La derivatives / nano-rare earth-based complexes employed in this application can achieve efficient and green phosphorus removal and shorten the phosphorus removal cycle.

Description

Technical Field

[0001] This application relates to the field of pollutant treatment technology, and in particular to a method for synergistic phosphorus removal by chlorophyll-La derivative / nano-rare earth-based complex and its application. Background Technology

[0002] Existing phosphorus removal technologies mainly fall into two categories: natural processes and artificial intervention. Natural processes include sedimentation and adsorption, biological absorption, and microbial transformation. Artificial intervention technologies mainly include physicochemical methods, bio-ecological methods, sediment remediation, electrochemical methods, and membrane technology. However, physicochemical methods are fast but require continuous application of chemicals, and chemical agents have secondary impacts on the ecosystem. Bio-ecological methods are low-cost but have long cycles. Therefore, there is a need to develop phosphorus removal methods that are short-cycle, highly efficient, and environmentally friendly. Summary of the Invention

[0003] The purpose of this application is to provide a method for synergistic phosphorus removal using chlorophyll-La derivatives / nano-rare earth-based complexes and its application, achieving efficient and green phosphorus removal while shortening the phosphorus removal cycle. The specific technical solution is as follows:

[0004] The first aspect of this application provides a method for synergistic phosphorus removal, comprising: adding a mixture of a nano-rare earth-based complex and a chlorophyll-La derivative to a phosphorus-containing pollutant, and subjecting the pollutant to light treatment to remove phosphorus; wherein the phosphorus-containing pollutant is selected from phosphorus-containing water bodies or phosphorus-containing soil; the nano-rare earth-based complex comprises nano-lanthanum oxide, nano-chitosan, modified calcium and magnesium mineral materials, biochar, zeolite, excipients, and regulators.

[0005] In some embodiments of this application, the mass ratio of the mixture of the nano-rare earth-based composite and the chlorophyll-La derivative to the phosphorus-containing pollutant is 1:(1-5); the phosphorus concentration in the phosphorus-containing water is 1 mg / L to 20 mg / L; the phosphorus concentration in the phosphorus-containing soil is 1 mg / kg to 20 mg / kg; the pH value of the phosphorus-containing pollutant is 3-10; the wavelength of the light source used in the light treatment is 400 nm-700 nm; the temperature of the light treatment is 20℃-80℃; and the time of the light treatment is 2h-10h.

[0006] In some embodiments of this application, the preparation method of the mixture of the nano-rare earth-based composite and chlorophyll-La derivative includes the following steps:

[0007] Method 1: A chlorophyll-La derivative is uniformly sprayed onto the surface of the nano-rare earth-based composite and dried to obtain a mixture of the nano-rare earth-based composite and the chlorophyll-La derivative; or

[0008] Method 2: The chlorophyll-La derivative and the nano-rare earth-based complex are mechanically mixed and wet-granulated to obtain a mixture of the nano-rare earth-based complex and the chlorophyll-La derivative.

[0009] In some embodiments of this application, method one includes the steps of: dissolving the chlorophyll-La derivative in an organic solvent to obtain a loading solution with a concentration of 10 mg / mL-20 mg / mL; uniformly spraying the loading solution onto the surface of the nano-rare earth-based composite; allowing it to stand and age before drying to obtain a mixture of the nano-rare earth-based composite and the chlorophyll-La derivative; the organic solvent is selected from 70 vol%-100 vol% ethanol solution; the mass ratio of the nano-rare earth-based composite to the chlorophyll-La derivative is 10:(1-4).

[0010] In some embodiments of this application, in method two, the mass ratio of the nano-rare earth-based composite and the chlorophyll-La derivative is (8-9):(1-2).

[0011] In some embodiments of this application, the raw material components of the nano-rare earth-based composite, by weight, include: 40-74 parts of nano-lanthanum oxide, 5-46 parts of nano-chitosan, 5-26 parts of modified calcium-magnesium mineral material, 5-35 parts of biochar, 3-25 parts of zeolite, 1-9 parts of excipients, and 1-5 parts of regulator; the average particle size Dv50 of the nano-lanthanum oxide is 10nm-100nm; the average particle size Dv50 of the nano-chitosan is 10nm-100nm; the nano-chitosan includes chitosan nanocrystals, chitosan nanofibers, and chitosan. The modified calcium-magnesium mineral material comprises at least one of chitosan nanocomposite fibers; the excipients include at least one of dextrin, polyvinyl alcohol, starch, carboxymethyl cellulose, and sodium alginate; the modifiers include at least one of calcium chloride, calcium sulfate, calcium nitrate, magnesium sulfate, magnesium chloride, magnesium nitrate, potassium chloride, potassium nitrate, and potassium sulfate; the preparation method of the modified calcium-magnesium mineral material includes the steps of: acid treatment of the mineral raw material, followed by heating to 150℃-560℃, and then pressurizing to 22MPa-30MPa to react; the mineral raw material contains ≥20% calcium or ≥15% magnesium by mass.

[0012] In some embodiments of this application, the preparation method of the chlorophyll-La derivative includes: mixing chlorophyll a with a first organic solvent to obtain a first mixture; the first organic solvent is selected from at least one of methanol, dichloromethane, ethanol, isopropanol, hexane and acetone; mixing the first mixture with an acid solution to remove magnesium to obtain a second mixture; mixing the second mixture with La2O3 and then subjecting it to microwave irradiation to obtain the chlorophyll-La derivative.

[0013] In some embodiments of this application, in the method for preparing chlorophyll-La derivatives, the mass-to-volume ratio of chlorophyll a to the first organic solvent is 1 g:(10-50) mL; the volume ratio of the first mixture to the acid solution is 1:(1-3); the acid solution is selected from HCl solution with a concentration of 0.1 mol / L-1 mol / L, acetic acid solution with a concentration of 0.05 mol / L-0.5 mol / L, or sulfuric acid solution with a concentration of 0.5 mol / L-2 mol / L; the volume-to-mass ratio of the second mixture to La2O3 is 1 mL:(0.5-2) g; the microwave radiation frequency is 1000 MHz-2500 MHz, the radiation temperature is 50℃-90℃, and the radiation time is 5 min-60 min.

[0014] In some embodiments of this application, the preparation method of the chlorophyll-La derivative includes: extracting biomass raw materials with a second organic solvent, collecting the liquid to obtain an extract containing chlorophyll a; wherein the biomass raw materials include at least one of spirulina, spinach, and silkworm excrement; the second organic solvent is selected from at least one of dichloromethane, methanol, ethanol, isopropanol, hexane, and acetone; mixing the extract containing chlorophyll a with a third organic solvent, collecting the liquid to obtain a third mixture, wherein the third organic solvent is selected from a methanol solution containing 1 w / v%-10 w / v% sodium hydroxide; mixing the third mixture with La2O3 and subjecting it to microwave irradiation, then filtering to remove solid impurities to obtain the chlorophyll-La derivative.

[0015] In some embodiments of this application, in the preparation method of the chlorophyll-La derivative, the mass ratio of the biomass raw material to the second organic solvent is 1:(3-20); the volume ratio of the extract containing chlorophyll a to the third organic solvent is 1:(0.5-5); the mass ratio of the biomass raw material to La2O3 is 100:(1-10); the microwave radiation frequency is 1000MHz-2500MHz, the radiation temperature is 50℃-80℃, and the radiation time is 10min-60min.

[0016] The second aspect of this application provides the application of the method described in the first aspect of this application in the purification treatment of phosphorus-containing water bodies or the remediation of phosphorus-containing soils.

[0017] The beneficial effects of this application are:

[0018] This application provides a method for synergistic phosphorus removal using chlorophyll-La derivatives / nano-rare earth-based complexes. The polar groups of the porphyrin ring side chains of the chlorophyll-La derivatives can adsorb phosphate ions, providing a reaction interface for ligand exchange. Lanthanum ions have a high phosphorus-locking capacity, and the porous structure of the nano-rare earth-based complex provides abundant adsorption sites, improving adsorption capacity and selectivity, and increasing the ligand exchange rate. Under light treatment, solar-driven in-situ remediation can achieve efficient and green removal of organic phosphorus and adsorption of inorganic phosphorus, with a phosphorus removal rate of over 60% and a shortened phosphorus removal cycle.

[0019] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Detailed Implementation

[0020] The technical solutions of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0021] This application provides a method for synergistic phosphorus removal, comprising: adding a mixture of a nano-rare earth-based composite and a chlorophyll-La derivative to a phosphorus-containing pollutant, followed by phototreatment to remove phosphorus; wherein the phosphorus-containing pollutant is selected from phosphorus-containing water or phosphorus-containing soil; the nano-rare earth-based composite comprises nano-lanthanum oxide, nano-chitosan, modified calcium-magnesium mineral materials, biochar, zeolite, excipients, and regulators. Preferably, the modified calcium-magnesium mineral materials are obtained by acid treatment of mineral raw materials.

[0022] The inventors of this application discovered in their research that chlorophyll-La derivatives enhance phosphorus adsorption through ligand exchange, exhibiting a highly efficient phosphorus-locking effect. The core porphyrin ring of the chlorophyll-La derivative is related to La... 3+ Coordination structure of La: 3+ Lanthanum ions, as the central metal ion, form coordinate bonds with the four nitrogen atoms of the porphyrin ring, constituting a stable five-membered ring structure. Furthermore, La... 3+ The coordination number is typically 8-9, and its outer empty orbit (5d) 0 6s 0 It can accept lone pairs of electrons from additional ligands, providing sites for ligand exchange.

[0023] The surface functional groups of chlorophyll-La derivatives, namely the side chains of the porphyrin ring (such as propionic acid groups and phytol chains), contain polar groups such as carboxyl groups (-COOH) and hydroxyl groups (-OH), which can adsorb phosphate ions (PO4) through hydrogen bonding or electrostatic interactions. 3- ), providing a reaction interface for ligand exchange.

[0024] La 3+La possesses phosphorus affinity properties. 3+ It belongs to the class of hard Lewis acids (ionic radius 1.032 Å), and is similar to hard Lewis bases (such as O). 2- OH - PO4 3- PO4 has a strong coordination tendency. 3- The O atom in it can interact with La 3+ It forms stable coordination bonds (bond energy approximately 100 kJ / mol-150 kJ / mol), and its affinity is significantly higher than that of chlorophyll porphyrin ring proligands (such as nitrogen atoms and water molecules). The La in chlorophyll-La derivatives... 3+ Typically coordinated with water molecules (H2O) or hydroxyl groups (OH) - ), forming [La(OH2)] n ] 3+ Or [La(OH)] m ] (3-m)+ (n=6-9, m=1-3). Among phosphorus-containing pollutants, for example, in phosphorus-containing water bodies, PO4... 3- As a stronger ligand, it will replace these weakly coordinated water molecules or hydroxyl groups, strengthening the binding to phosphorus. The optimal reaction system is a weakly alkaline system. Under alkaline conditions (pH > 7), OH... - Concentration increases, with PO4 3- Competing coordination sites; under acidic conditions (pH < 5), PO4 3- Mainly H2PO4 - / HPO4 2- The form exists, but the coordination ability is weakened, and the optimal pH for ligand exchange is 5-7.

[0025] Electrostatic attraction: The carboxyl groups on the surface of chlorophyll-La derivatives ionize to -COO at neutral pH. - With the negatively charged PO4 3- (At pH 5-7, it is mainly HPO4) 2- There is electrostatic repulsion, but La 3+ The positive charge can neutralize part of the repulsive force, forming "La". 3+ -PO4 3- "The synergistic effect of primary adsorption and carboxyl-assisted coordination."

[0026] Hydrogen bonding: The hydroxyl groups (-OH) on the side chains of the porphyrin ring can react with PO4. 3- The O atoms form hydrogen bonds (OH…O), further enhancing the adsorption strength. This effect is observed in the infrared spectrum at 3400 cm⁻¹. -1 The shift of the hydroxyl peak.

[0027] La 3+ For PO4 3- The affinity is much higher than that of common anions (such as SO42-).2- Cl - In phosphorus-containing water bodies (e.g., phosphorus concentrations of 1 mg / L to 20 mg / L), ligand exchange preferentially occurs, resulting in efficient phosphorus removal. Furthermore, the nano-rare earth-based complex provides abundant adsorption sites, exhibiting porosity and high phosphorus retention capacity; chlorophyll-La derivatives loaded onto the nano-rare earth-based complex achieve a specific surface area of ​​up to 50 m². 2 / g-100m 2 / g, La at the interface 3+ With PO4 3- The ligand exchange rate is increased by 30%-50%.

[0028] The polar groups of the porphyrin ring side chains of chlorophyll-La derivatives can adsorb phosphate ions, providing a reaction interface for ligand exchange. Lanthanum ions have phosphorus affinity and high phosphorus locking capacity, which can fix phosphorus. Combined with the porous structure of the nano-rare earth-based complex, the adsorption capacity and adsorption selectivity of phosphorus are improved, thereby achieving efficient and green removal of organic phosphorus and adsorption of inorganic phosphorus, with a short phosphorus removal cycle.

[0029] In one embodiment of this application, the mass ratio of the mixture of the nano-rare earth-based complex and the chlorophyll-La derivative to the phosphorus-containing pollutant is 1:(1-5). For example, the mass ratio of the mixture of the nano-rare earth-based complex and the chlorophyll-La derivative to the phosphorus-containing pollutant can be 1:1, 1:2, 1:3, 1:4, 1:5, or a range consisting of any two of these ratios. Controlling the mass ratio of the mixture of the nano-rare earth-based complex and the chlorophyll-La derivative to the phosphorus-containing pollutant within the above range is beneficial for improving the phosphorus removal rate.

[0030] In one embodiment of this application, the concentration of phosphorus in the phosphorus-containing water body is from 1 mg / L to 20 mg / L. For example, the concentration of phosphorus in the phosphorus-containing pollutant can be 1.0 mg / L, 1.5 mg / L, 2.0 mg / L, 2.5 mg / L, 3.0 mg / L, 3.5 mg / L, 3.8 mg / L, 4.0 mg / L, 4.2 mg / L, 4.4 mg / L, 4.6 mg / L, 4.8 mg / L, 5.0 mg / L, 5.2 mg / L, 5.4 mg / L, 5.6 mg / L, 5.8 mg / L, 6.0 mg / L, 6.2 mg / L, 6.4 mg / L, 6.5 mg / L, 7 mg / L, 9 mg / L, 10 mg / L, 12 mg / L, 14 mg / L, 16 mg / L, 18 mg / L, 20 mg / L, or a range of any two of these values.

[0031] In one embodiment of this application, the concentration of phosphorus in the phosphorus-containing soil is from 1 mg / kg to 20 mg / kg. For example, the concentration of phosphorus in the phosphorus-containing pollutant can be 1.0 mg / kg, 1.5 mg / kg, 2.0 mg / kg, 2.5 mg / kg, 3.0 mg / kg, 3.5 mg / kg, 3.8 mg / kg, 4.0 mg / kg, 4.2 mg / kg, 4.4 mg / kg, 4.6 mg / kg, 4.8 mg / kg, 5.0 mg / kg, 5.2 mg / kg, 5.4 mg / kg, 5.6 mg / kg, 5.8 mg / kg, 6.0 mg / kg, 6.2 mg / kg, 6.4 mg / kg, 6.5 mg / kg, 7 mg / kg, 9 mg / kg, 10 mg / kg, 12 mg / kg, 14 mg / kg, 16 mg / kg, 18 mg / kg, 20 mg / kg, or a range of any two of these values.

[0032] In one embodiment of this application, the pH value of the phosphorus-containing pollutant is 3-10; in another embodiment, the pH value is 5-7. For example, the pH value of the phosphorus-containing pollutant can be 3, 4, 5, 5.5, 6, 6.5, 7, 8, 9, 10, or a range of any two of these values. Chlorophyll-La derivatives enhance phosphorus adsorption through ligand exchange, and ligand exchange reactions can still occur when the pH of the phosphorus-containing pollutant is 3-10. Specifically, under alkaline conditions (pH > 7), OH... - Concentration increases, with PO4 3- Competing coordination sites; under acidic conditions (pH < 5), PO4 3- Mainly H2PO4 - / HPO4 2- The form exists, but the coordination ability is weakened. The optimal ligand exchange is 5-7, which can enhance the La at the reaction interface. 3+ With PO4 3- High ligand exchange rate for efficient phosphorus removal.

[0033] In one embodiment of this application, the wavelength of the light source used in the light treatment is 400nm-700nm, the temperature of the light treatment is 20℃-80℃, and the time of the light treatment is 2h-10h. For example, the wavelength of the light source can be 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, or any range of any two values ​​therein; the temperature of the light treatment can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, or any range of any two values ​​therein; the time of the light treatment can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, or any range of any two values ​​therein. This application employs light-based treatment and solar-driven in-situ remediation, which is beneficial for improving the phosphorus removal rate and shortening the phosphorus removal cycle.

[0034] In one embodiment of this application, during the light treatment, stirring or shaking can also be performed to increase the ligand exchange rate and achieve efficient phosphorus removal. In this application, there are no particular limitations on the intensity of stirring or shaking, as long as the inventive objective of this application is achieved.

[0035] In one embodiment of this application, the mixture of nano-rare earth-based complex and chlorophyll-La derivative is added to phosphorus-containing pollutants by spraying, specifically by using drones or manual spraying.

[0036] In one embodiment of this application, the preparation method of the mixture of nano-rare earth-based complex and chlorophyll-La derivative includes the following steps: Method 1: uniformly spraying chlorophyll-La derivative onto the surface of nano-rare earth-based complex and drying it to obtain a mixture of nano-rare earth-based complex and chlorophyll-La derivative.

[0037] In one embodiment of this application, method one includes the steps of: dissolving a chlorophyll-La derivative in an organic solvent to obtain a loading solution with a concentration of 10 mg / mL-20 mg / mL; uniformly spraying the loading solution onto the surface of the nano-rare earth-based composite; allowing it to stand and age before drying to obtain a mixture of the nano-rare earth-based composite and the chlorophyll-La derivative; the organic solvent is selected from 70 vol%-100 vol% ethanol solution (if not 100 vol%, the solvent is water); the mass ratio of the nano-rare earth-based composite to the chlorophyll-La derivative is 10:(1-4). For example, the concentration of the supporting solution can be 10 mg / mL, 12 mg / mL, 14 mg / mL, 16 mg / mL, 18 mg / mL, 20 mg / mL, or any combination of two of these values; the concentration of the organic solvent ethanol solution can be 70 vol%, 80 vol%, 90 vol%, 1000 vol%, or any combination of two of these values; the mass ratio of the nano-rare earth-based composite to the chlorophyll-La derivative can be 10:1, 10:2, 10:3, 10:4, or any combination of two of these ratios. This application achieves this by uniformly spraying the supporting solution containing the chlorophyll-La derivative onto the surface of the nano-rare earth-based composite. The porous nano-rare earth-based composite provides abundant adsorption sites, enhancing the adsorption capacity and selectivity of phosphorus and increasing the La adsorption capacity at the reaction interface. 3+ With PO4 3- The ligand exchange rate is high, and lanthanum ions have a highly efficient phosphorus-locking ability. The polar groups of the side chains of the porphyrin ring in chlorophyll-La derivatives can adsorb phosphate ions (PO4). 3- This provides a reaction interface for ligand exchange, thereby achieving efficient and green phosphorus removal and shortening the phosphorus removal cycle.

[0038] In this application, there are no particular restrictions on the method of dissolving chlorophyll-La derivatives in organic solvents, as long as the purpose of this application can be achieved. For example, ultrasonic dissolution (power 150W-250W, time 5min-15min) can be used to ensure thorough mixing.

[0039] In this application, there are no particular restrictions on the method of uniform spraying, as long as it can achieve the purpose of this application. For example, a sprayer with an aperture of 0.5 mm to 1 mm can be used to uniformly spray the loading liquid onto the surface of the nano-rare earth-based composite. Stirring is carried out during the spraying process. After spraying is completed, the mixture is left to stand at room temperature for 1 to 3 hours to allow the chlorophyll-La derivative to be uniformly adsorbed onto the surface of the nano-rare earth-based composite.

[0040] In one embodiment of this application, there are no particular limitations on the drying method, as long as it can achieve the purpose of this application. For example, the nano-rare earth-based composite with the loading liquid attached to its surface can be placed in a vacuum drying oven (drying temperature 10℃-30℃, pressure <0.05MPa) for 6h-18h, which helps to avoid chlorophyll decomposition caused by high temperature.

[0041] In one embodiment of this application, the preparation method of the mixture of nano-rare earth-based complex and chlorophyll-La derivative includes the following steps: Method 2: mechanically mixing chlorophyll-La derivative and nano-rare earth-based complex, wet granulation, to obtain the mixture of nano-rare earth-based complex and chlorophyll-La derivative.

[0042] In one embodiment of this application, in method two, the mass ratio of the nano-rare earth-based complex to the chlorophyll-La derivative is (8-9):(1-2). For example, the mass ratio of the nano-rare earth-based complex to the chlorophyll-La derivative can be 8:1, 8.2:1.8, 8.5:1.5, 8.8:1.2, 9:1, or any range of two of these ratios.

[0043] In this application, there are no particular restrictions on the mechanical mixing method, as long as it can achieve the purpose of this application. For example, the mechanical mixing method can be: adding the nano-rare earth-based complex and chlorophyll-La derivative into a high-speed mixer, and mixing at 200 rpm to 400 rpm for 10 to 20 minutes under low temperature (e.g., -20℃ to 10℃) and light-protected conditions to obtain a uniformly dispersed mixture.

[0044] In this application, there are no particular limitations on the high-speed mixer, as long as it can achieve the purpose of this application. For example, the high-speed mixer can be a double cone mixer.

[0045] In this application, there are no particular restrictions on the wet granulation method, as long as it achieves the purpose of this application. For example, the wet granulation method can be as follows: mix the mixture obtained by mechanical mixing with a binder to produce wet granules with an average particle size Dv50 of 2mm-3mm, and granulate them by passing them through a 10-mesh (1.65mm) sieve (i.e., take the wet granules on the sieve); place the wet granules in a dryer (inlet air temperature of 15℃-25℃, air volume of 5m³ / h). 3 / h-15m 3 / h) Dry to a moisture content of <5%, with a drying time of 2-6 hours; wherein, the mass ratio of the mixture obtained by mechanical mixing to the binder is 10:(0.5-1.5), and the binder is selected from an aqueous solution containing 2vol%-8vol% polyvinyl alcohol.

[0046] In this application, there are no particular restrictions on the granulation method, as long as it achieves the purpose of this application. For example, it can be prepared by a granulator such as a swing granulator.

[0047] In this application, there are no particular limitations on the dryer, as long as it can achieve the purpose of this application. For example, the dryer can be a fluidized bed dryer.

[0048] In this application, there are no particular limitations on the shape of the particles of the mixture of nano-rare earth-based composite and chlorophyll-La derivative, as long as the purpose of this application can be achieved. For example, they can be spherical or cylindrical. Specifically, the dried particles can be pressed into shape by a tablet press (pressure 5MPa-10MPa), or spherical particles can be prepared by an extrusion-spheronization machine (speed 400rpm-600rpm, spheronization time 20min-40min).

[0049] In one embodiment of this application, the raw material components of the nano-rare earth-based composite, by weight, include: 40-74 parts of nano-lanthanum oxide, 5-46 parts of nano-chitosan, 5-26 parts of modified calcium-magnesium mineral material, 5-35 parts of biochar, 3-25 parts of zeolite, 1-9 parts of excipients, and 1-5 parts of regulator. For example, the nano-lanthanum oxide can be 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 74 parts, or any two of these values; the nano-chitosan can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 46 parts, or any two of these values; the modified calcium-magnesium mineral material can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 2... 6 parts or any two of these values; biochar can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts or any two of these values; zeolite can be 3 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts or any two of these values; excipients can be 1 part, 3 parts, 5 parts, 6 parts, 9 parts or any two of these values; regulators can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts or any two of these values.

[0050] The preparation method of the nano-rare earth-based composite in this application may include the following steps: mixing all raw material components evenly according to the ratio, then pulverizing them, passing them through a 100-mesh (150μm) sieve, and collecting the powder that passes through the sieve, which is the nano-rare earth-based composite.

[0051] In one embodiment of this application, the average particle size Dv50 of nano-lanthanum oxide is 10nm-100nm; the average particle size Dv50 of nano-chitosan is 10nm-100nm; in another embodiment of this application, the average particle size Dv50 of nano-lanthanum oxide is 40nm-60nm, and the average particle size Dv50 of nano-chitosan is 60nm-80nm. For example, the average particle size Dv50 of nano-lanthanum oxide can be 10nm, 20nm, 30nm, 40nm, 45nm, 50nm, 55nm, 60nm, 70nm, 80nm, 90nm, 100nm, or a range consisting of any two of these values; the average particle size Dv50 of nano-chitosan can be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 65nm, 70nm, 75nm, 80nm, 90nm, 100nm, or a range consisting of any two of these values.

[0052] In this application, Dv50 represents the particle size that, from the smallest particle size side, reaches 50% of the total volumetric particle size distribution. Dv50 in this application can be obtained using a laser particle size analyzer.

[0053] In one embodiment of this application, the nano-chitosan includes at least one of chitosan nanocrystals, chitosan nanofibers, and chitosan-chitosan nanocomposite fibers.

[0054] In one embodiment of this application, the excipients include at least one selected from dextrin, polyvinyl alcohol, starch, carboxymethyl cellulose, and sodium alginate.

[0055] In one embodiment of this application, the regulator includes at least one of calcium chloride, calcium sulfate, calcium nitrate, magnesium sulfate, magnesium chloride, magnesium nitrate, potassium chloride, potassium nitrate, and potassium sulfate.

[0056] In one embodiment of this application, the preparation method of the modified calcium-magnesium mineral material includes the following steps: acid treatment of the mineral raw material, followed by heating to 150℃-560℃, and then pressurizing to 22MPa-30MPa to react; the mineral raw material contains a calcium element mass fraction ≥20% or a magnesium element mass fraction ≥15%. The mineral raw material can be one or a combination of several of calcite, limestone, magnesite, and olivine. All mineral raw materials used in this application can be purchased from commercial channels. For example, calcite and limestone can be purchased from Shunze Mineral Products Processing Plant in Lingshou County, magnesite can be purchased from Hongqi Magnesium Sand Mine in Pailou Town, Haicheng City, and olivine can be purchased from Hongqi Magnesium Sand Mine in Pailou Town, Haicheng City. For example, the heating temperature can be 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 560℃, or a range of any two of these values; the pressure can be 22MPa, 24MPa, 26MPa, 28MPa, 30MPa, or a range of any two of these values.

[0057] In this application, the acid treatment of the modified calcium-magnesium mineral material includes: mixing the mineral raw material with a second acid solution, wherein the mass-to-volume ratio of the mineral raw material to the second acid solution is 1:(5-20), and the second acid solution is selected from HCl solution with a concentration of 1mol / L-12mol / L, nitric acid solution with a concentration of 0.5mol / L-15mol / L, or sulfuric acid solution with a concentration of 0.5mol / L-18mol / L.

[0058] In this application, there are no particular restrictions on the source of nano-lanthanum oxide, as long as it can achieve the purpose of this invention. For example, nano-lanthanum oxide (CAS: 1312-81-8) can be purchased from the market or prepared. For example, the preparation method of nano-lanthanum oxide can be as follows: dissolve lanthanum salt (such as La(NO3)3·6H2O or LaCl3) in water, add a precipitant (NaOH, NH4OH or oxalic acid), adjust the pH to 9-11, and generate La(OH)3 or La2(C2O4)3. Centrifuge to remove impurities, dry at 60℃-80℃; add polyethylene glycol 2000 to inhibit particle agglomeration, and heat treat at 200℃-800℃ to obtain nano-lanthanum oxide with a particle size of 10nm-100nm. Alternatively, the preparation method of nano-lanthanum oxide can be as follows: dissolve lanthanum salt (such as La(NO3)3·6H2O or LaCl3) in water, add precipitant (NaOH, NH4OH or oxalic acid), adjust the pH to 9-10, stir in a water bath at 50℃-70℃ for 1h-3h to generate hydroxide precipitate; after centrifugation at 7000rpm-9000rpm for 9min-11min, wash with deionized water 2-4 times, and calcine at 400℃-600℃ for 3h-5h to obtain nano-lanthanum oxide with a particle size of 10nm-100nm.

[0059] This application does not impose any particular restrictions on the source of biochar and zeolite, both of which can be purchased through commercial channels. For example, biochar can be purchased from Henan Zunguan Water Purification Materials Co., Ltd., and zeolite can be purchased from Beijing Hongbo Guangtai Technology Co., Ltd.

[0060] In one embodiment of this application, the method for preparing chlorophyll-La derivatives includes: mixing chlorophyll a with a first organic solvent to obtain a first mixture; the first organic solvent is selected from at least one of methanol, dichloromethane, ethanol, isopropanol, hexane, and acetone; mixing the first mixture with an acid solution to remove magnesium, obtaining a second mixture, wherein the acid solution is referred to as the first acid solution; and mixing the second mixture with La2O3 and subjecting it to microwave irradiation to obtain the chlorophyll-La derivative. This application utilizes renewable biomass resources to prepare chlorophyll-La derivative catalytic materials, significantly reducing preparation costs, achieving resource recycling, and conforming to the development concept of green chemistry. Furthermore, by combining it with a microwave-assisted green synthesis process, the preparation process is further simplified, production efficiency is improved, and the preparation method is made more environmentally friendly and safer.

[0061] In one embodiment of this application, the mass-to-volume ratio of chlorophyll a to the first organic solvent is 1 g: (10-50) mL. For example, the mass-to-volume ratio of chlorophyll a to the first organic solvent can be 1 g: 10 mL, 1 g: 20 mL, 1 g: 30 mL, 1 g: 40 mL, 1 g: 50 mL, or a range between any two of these ratios.

[0062] In one embodiment of this application, the volume ratio of the first mixture to the first acid solution is 1:(1-3); the first acid solution is selected from an HCl solution with a concentration of 0.1 mol / L to 1 mol / L, a sulfuric acid solution with a concentration of 0.05 mol / L to 0.5 mol / L, or an acetic acid solution with a concentration of 0.5 mol / L to 2 mol / L. For example, the volume ratio of the first mixture to the first acid solution can be 1:1, 1:2, 1:3, or a range between any two of these ratios.

[0063] In one embodiment of this application, the volume-to-mass ratio of the second mixture to La2O3 is 1 mL:(0.5-2) g. For example, the volume-to-mass ratio of the second mixture to La2O3 can be 1 mL:0.5 g, 1 mL:1 g, 1 mL:1.5 g, 1 mL:2 g, or a range between any two of these ratios.

[0064] In one embodiment of this application, the microwave radiation frequency is 1000MHz-2500MHz, the radiation temperature is 50℃-90℃, and the radiation time is 5min-60min; in another embodiment of this application, the radiation temperature is 60℃-80℃, and the radiation time is 10min-20min. For example, the radiation frequency of microwave radiation can be 1000MHz, 1200MHz, 1400MHz, 1600MHz, 1800MHz, 2000MHz, 2200MHz, 2400MHz, 2420MHz, 2440MHz, 2460MHz, 2480MHz, 2500MHz, or a range of any two of these values; the radiation temperature can be 50℃, 60℃, 65℃, 70℃, 75℃, 80℃, 90℃, or a range of any two of these values; the radiation time can be 5min, 10min, 12min, 14min, 16min, 18min, 20min, 30min, 40min, 50min, 60min, or a range of any two of these values.

[0065] In this application, there are no particular restrictions on the source of chlorophyll a (CAS No.: 479-61-8), as long as it can achieve the purpose of this application. For example, chlorophyll a can be obtained from the market or prepared by conventional methods in the art.

[0066] In one embodiment of this application, the method for preparing chlorophyll-La derivatives includes: extracting biomass raw materials with a second organic solvent, collecting the liquid to obtain an extract containing chlorophyll a; wherein the biomass raw materials include at least one of spirulina, spinach, and silkworm excrement; the second organic solvent is selected from at least one of dichloromethane, methanol, ethanol, isopropanol, hexane, and acetone; mixing the extract containing chlorophyll a with a third organic solvent, collecting the liquid to obtain a third mixture, wherein the third organic solvent is selected from a methanol solution containing 1 w / v%-10 w / v% sodium hydroxide; mixing the third mixture with La2O3 and subjecting it to microwave irradiation, then filtering to remove solid impurities to obtain chlorophyll-La derivatives.

[0067] This application utilizes biomass resources to prepare chlorophyll-La derivatives, which can significantly reduce preparation costs, realize resource recycling, and conform to the development concept of green chemistry. Furthermore, by combining it with microwave-assisted green synthesis technology, the preparation process is further simplified, production efficiency is improved, and the preparation method is made more environmentally friendly, efficient, and safe.

[0068] In this application, there are no particular restrictions on the filtration method, as long as it meets the purpose of this application. For example, it can be a plate and frame filter or a centrifugal filter.

[0069] In one embodiment of this application, the mass ratio of biomass feedstock to the second organic solvent is 1:(3-20). For example, the mass ratio of biomass feedstock to the second organic solvent can be 1:3, 1:5, 1:10, 1:15, 1:20, or a range between any two of these ratios.

[0070] In one embodiment of this application, the volume ratio of the extract containing chlorophyll a to the third organic solvent is 1:(0.5-5). For example, the volume ratio of the extract containing chlorophyll a to the third organic solvent can be 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, or a range between any two of these ratios.

[0071] In one embodiment of this application, the mass ratio of biomass feedstock to La2O3 is 100:(1-10). For example, the mass ratio of biomass feedstock to La2O3 can be 100:1, 100:2, 100:4, 100:6, 100:8, 100:10, or a range between any two of these ratios.

[0072] In one embodiment of this application, the microwave radiation frequency is 1000MHz-2500MHz, the radiation temperature is 50℃-80℃, and the radiation time is 10min-60min. For example, the microwave radiation frequency can be 1000MHz, 1200MHz, 1400MHz, 1600MHz, 1800MHz, 2000MHz, 2200MHz, 2400MHz, 2420MHz, 2440MHz, 2460MHz, 2480MHz, 2500MHz, or a range of any two of these values; the radiation temperature can be 50℃, 60℃, 70℃, 80℃, or a range of any two of these values; and the radiation time can be 10min, 20min, 30min, 40min, 50min, 60min, or a range of any two of these values.

[0073] This application provides a method for synergistic phosphorus removal using chlorophyll-La derivatives / nano-rare earth-based complexes. The chlorophyll-La derivatives enhance phosphorus adsorption through ligand exchange, exhibiting highly efficient phosphorus locking. The composite nano-rare earth-based complex possesses porosity and high phosphorus locking capacity, which is beneficial for improving adsorption capacity and selectivity. Solar-driven in-situ remediation is employed, and precise spraying via drones can inhibit phosphorus release from sediment. This method can simultaneously degrade organic phosphorus and adsorb inorganic phosphorus, exhibiting controlled-release phosphorus removal. It has a wide pH adaptability (pH 3-10) and is suitable for various water quality and soil remediation applications.

[0074] The second aspect of this application provides an application of the method described in the first aspect of this application in the treatment of phosphorus-containing water bodies or the remediation of phosphorus-containing soil.

[0075] In one embodiment of this application, a porous filter element is prepared from a chlorophyll-La derivative / nano-rare earth-based composite and applied in a small water purification device.

[0076] Example

[0077] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0078] Detection of phosphorus concentration:

[0079] The phosphorus concentration in phosphorus-containing water bodies shall be detected in accordance with the "GB11893 / T-1989 Determination of Total Phosphorus in Water - Ammonium Molybdate Spectrophotometric Method"; when the phosphorus concentration in the sample is higher than 0.6 mg / L, the sample shall be diluted with deionized water before testing to ensure the accuracy of the test.

[0080] The phosphorus concentration in phosphorus-containing soils was determined according to the standard "Determination of Available Phosphorus in Soil - Sodium Bicarbonate Extraction-Molybdenum Antimony Spectrophotometric Method" (HJ 704-2014).

[0081] Using the above testing methods, the total phosphorus concentration of phosphorus-containing pollutants (i.e., initial concentration) and the total phosphorus concentration of the mixture after phosphorus removal (i.e., final concentration) were obtained respectively; then, the phosphorus removal rate was calculated according to the following formula:

[0082] Phosphorus removal rate (%) = (Total phosphorus concentration of phosphorus-containing pollutants - Total phosphorus concentration of the mixture after phosphorus removal) / Total phosphorus concentration of phosphorus-containing pollutants × 100%.

[0083] Example 1

[0084] 1. Preparation of chlorophyll-La derivatives

[0085] S11: Chlorophyll a is mixed with the first organic solvent methanol, and after 10 min of mixing, a first mixture is obtained; wherein, the mass-volume ratio of chlorophyll a to methanol is 1 g: 20 mL;

[0086] S12: The first mixture is mixed with a 0.5 mol / L HCl solution to remove magnesium, resulting in a second mixture; wherein the volume ratio of the first mixture to the HCl solution is 1:2.

[0087] S13: The second mixture is mixed with La2O3 particles and then subjected to microwave irradiation at a frequency of 2450MHz, a temperature of 80°C, and a duration of 15min to obtain a mixture containing chlorophyll-La derivatives; wherein the volume-to-mass ratio of the first mixture to La2O3 particles is 1mL:1g to obtain chlorophyll-La derivatives.

[0088] 2. Preparation of nano-rare earth-based composites

[0089] S21: The raw material components of the nano-rare earth-based composite are weighed according to the following parts by weight:

[0090] The following materials were selected: 57 parts of lanthanum oxide nanoparticles with an average particle size Dv50 of 50 nm; 25 parts of chitin nanoparticles (chitin nanofibers, manufactured by Zhejiang Jinke Pharmaceutical Co., Ltd.; product model JK-CNF-01) with an average particle size Dv50 of 70 nm; 15 parts of modified calcium and magnesium mineral materials; 15 parts of biochar (purchased from Henan Zunguan Water Purification Materials Co., Ltd.); 15 parts of zeolite (purchased from Beijing Hongbo Guangtai Technology Co., Ltd.); 1 part of sodium alginate as an excipient; and 1 part of calcium chloride as a regulator. All the above raw material components were mixed evenly, then pulverized and passed through a 100-mesh (150 μm) sieve. The powder passing through the sieve was taken as the nano-rare earth-based composite.

[0091] The preparation method of the modified calcium-magnesium mineral material is carried out according to the following steps:

[0092] Calcite (purchased from Shunze Mineral Products Processing Plant in Lingshou County) and magnesite (purchased from Hongqi Magnesia Sand Mining Co., Ltd. in Pailou Town, Haicheng City, batch number HY-LMS-150302-01) were mixed in a mass ratio of 1:1 and then mixed with a 1 mol / L HCl solution as a second acid solution. The mixture was then heated to 350℃ and pressurized to 26 MPa for reaction. After the reaction was completed, the mixture was filtered and dried to obtain the modified calcium-magnesium mineral material. The mass-volume ratio of the mineral raw material to the second acid solution was 1:10.

[0093] 3. Preparation of a mixture of rare earth nanocomposite and chlorophyll-La derivative

[0094] S31: Dissolve the chlorophyll-La derivative in an aqueous solution containing 75 vol% ethanol, and sonicate it (power 200W, time 10 min) to make it fully mixed and prepare a loading solution of 15 mg / mL.

[0095] S32: The loading liquid is uniformly sprayed onto the nano-rare earth-based composite using a sprayer (orifice diameter of 0.75 mm), wherein the mass ratio of the nano-rare earth-based composite to the chlorophyll-La derivative is 10:2.5; during the spraying process, the mixture is continuously stirred at a speed of 200 rpm to ensure uniform adhesion of the loading liquid.

[0096] S33: After spraying, allow the mixture to stand at room temperature for 2 hours to allow the chlorophyll-La derivative to adsorb onto the surface of the nano-rare earth-based composite. Place the loaded nano-rare earth-based composite in a vacuum drying oven (drying temperature 20℃, pressure <0.05MPa) for 12 hours to avoid chlorophyll decomposition due to high temperature, and obtain a mixture of nano-rare earth-based composite and chlorophyll-La derivative.

[0097] 4. Phosphorus removal using a mixture of nano-rare earth-based complexes and chlorophyll-La derivatives.

[0098] S41: Add a mixture of nano-rare earth-based complex and chlorophyll-La derivative to phosphorus-containing water, wherein the mass ratio of the mixture of nano-rare earth-based complex and chlorophyll-La derivative to phosphorus-containing water is 1:3.

[0099] S42: Irradiate the mixture at 25°C under a light source with a wavelength of 550nm for 5 hours, stirring continuously at 100rpm during the irradiation process to remove phosphorus and obtain a phosphorus-free mixture.

[0100] Phosphorus-containing water source: 10L of water was taken from ditches around Tianjin Binhai New Area. The pH was 5.2, the COD concentration was 40mg / L, the total phosphorus concentration (initial concentration) was 1.45mg / L, and the total nitrogen was 4.56mg / L.

[0101] The mixture after phosphorus removal: The effluent after S42 treatment has a COD concentration of 25 mg / L, a total phosphorus concentration (final concentration) of 0.09 mg / L, and a total nitrogen concentration of 2.71 mg / L.

[0102] Calculations show that the total phosphorus removal rate in phosphorus-containing water bodies is 93.8%.

[0103] Examples 2 to 3

[0104] Except for adjusting the spraying volume of the loading solution in step S32 of “3. Preparation of the mixture of nano-rare earth-based complex and chlorophyll-La derivative” so that the mass of the nano-rare earth-based complex and chlorophyll-La derivative is as shown in Table 1, the rest is the same as in Example 1. The source of phosphorus-containing water is the same as in Example 1.

[0105] Examples 4 to 5

[0106] Except for step S41, in "4. Phosphorus removal using a mixture of nano-rare earth-based complex and chlorophyll-La derivative," where the mass ratio of the mixture of nano-rare earth-based complex and chlorophyll-La derivative to the phosphorus-containing water is adjusted as shown in Table 1, the rest is the same as in Example 1. The source of the phosphorus-containing water is the same as in Example 1.

[0107] Examples 6 to 11

[0108] Except for adjusting the relevant parameters according to Table 1, everything else is the same as in Example 1. The source of the phosphorus-containing water is the same as in Example 1.

[0109] Example 12

[0110] Except for "1. Preparation of chlorophyll-La derivatives" which is prepared according to the following method, the rest is the same as in Example 1. The source of phosphorus-containing water is the same as in Example 1.

[0111] 1. Preparation of chlorophyll-La derivatives

[0112] S11: The biomass raw material spinach is extracted with ethanol as a second organic solvent, and the liquid is collected to obtain an extract containing chlorophyll a; wherein the mass ratio of spinach to ethanol is 1:10.

[0113] S12: Mix the extract containing chlorophyll a with a third organic solvent, collect the liquid to obtain a third mixture, wherein the third organic solvent is a methanol solution containing 5 w / v% sodium hydroxide; the volume ratio of the extract containing chlorophyll a to the third organic solvent is 1:3.

[0114] S13: The third mixture is mixed with La2O3 and then subjected to microwave irradiation at a frequency of 2450MHz, a temperature of 80°C, and a duration of 15min. Solid impurities are then removed by filtration to obtain a mixture containing chlorophyll-La derivatives. The mass ratio of the biomass raw material spinach to La2O3 is 100:5 to obtain chlorophyll-La derivatives.

[0115] Example 13

[0116] Except for "3. Preparation of the mixture of nano-rare earth-based complex and chlorophyll-La derivative" which is prepared according to the following method, the rest is the same as in Example 1. The source of phosphorus-containing water is the same as in Example 1.

[0117] 3. Preparation of a mixture of rare earth nanocomposite and chlorophyll-La derivative

[0118] S31: Add the nano-rare earth-based complex and chlorophyll-La derivative to a double cone mixer at a mass ratio of 8.5:1.5, mix at 300 rpm for 15 minutes at 5°C in the dark to obtain a uniformly dispersed mixture;

[0119] S32: Add 5 vol% of polyvinyl alcohol aqueous solution to the mixture obtained in step S31. The mass ratio of the mixture to the binder is 10:1. Make wet granules with an average particle size Dv50 of 2.5 mm in a swing granulator. Sieve through a 10-mesh (1.65 mm) sieve to granulate and take the wet granules on the sieve.

[0120] S33: Place the wet particles in a fluidized bed dryer (inlet air temperature 20℃, air volume 10m³ / h). 3 Dry until the moisture content is <5% for 4 hours to obtain dried granules;

[0121] S34: The particles are extruded and spherical particles are prepared by an extrusion-spherical mill at a speed of 500 rpm and a spherical time of 30 min to obtain spherical particles of a mixture of nano-rare earth-based composite and chlorophyll-La derivative.

[0122] Example 14

[0123] Except for adjusting the mass ratio of the nano-rare earth-based complex to the chlorophyll-La derivative in step S31 of “3. Preparation of the mixture of nano-rare earth-based complex and chlorophyll-La derivative” as shown in Table 1, the rest is the same as in Example 13. The source of phosphorus-containing water is the same as in Example 13.

[0124] Example 15

[0125] Except for adjusting the mass ratio of the nano-rare earth-based complex to the chlorophyll-La derivative in step S31 of “3. Preparation of the mixture of nano-rare earth-based complex and chlorophyll-La derivative” as shown in Table 1, and preparing “4. Phosphorus removal using the mixture of nano-rare earth-based complex and chlorophyll-La derivative” according to the following method, the rest is the same as in Example 13.

[0126] 4. Phosphorus removal using a mixture of nano-rare earth-based complexes and chlorophyll-La derivatives.

[0127] S41: Add a mixture of nano-rare earth-based complex and chlorophyll-La derivative to phosphorus-containing soil, wherein the mass ratio of the mixture of nano-rare earth-based complex and chlorophyll-La derivative to phosphorus-containing soil is 1:3.

[0128] S42: Irradiate the mixture at 25°C under a light source with a wavelength of 550nm for 5 hours, stirring continuously at 100rpm during the irradiation process to remove phosphorus and obtain a phosphorus-free mixture.

[0129] Phosphorus-containing soil source: 10 kg of soil from a grape orchard in the northern part of Binhai New Area, Tianjin, with a pH of 6.8 and a total phosphorus concentration (initial concentration) of 15.8 mg / kg.

[0130] The mixture after phosphorus removal: After S42 treatment, the total phosphorus concentration (final concentration) in the soil after phosphorus removal is 0.74 mg / kg.

[0131] Calculations show that the total phosphorus removal rate in phosphorus-containing soils is 95.3%.

[0132] Example 16

[0133] Except for the preparation method of the modified calcium-magnesium mineral material, which follows the same steps, the rest is the same as in Example 1; the source of phosphorus-containing water is the same as in Example 1.

[0134] Preparation method of modified calcium-magnesium mineral material: Calcite (manufacturer: Shunze Mineral Products Processing Plant, Lingshou County) and magnesite (manufacturer: Hongqi Magnesia Sand Mining Co., Ltd., Pailou Town, Haicheng City, batch number: HY-LMS-150302-01) were mixed in a mass ratio of 1:1. The mixture was then impregnated in a 2 mol / L potassium hydroxide aqueous solution for modification treatment. The impregnation temperature was 50℃ and the impregnation time was 3 h. The impregnated calcium-magnesium mineral material was washed until neutral and then evaporated to dryness to obtain the modified calcium-magnesium mineral material. The mass-volume ratio of the mineral raw material to the potassium hydroxide aqueous solution was 1 g: 2 mL.

[0135] Comparative Example 1

[0136] Except for adjusting the amount of modified calcium-magnesium mineral material according to Table 1, everything else is the same as in Example 1. The source of phosphorus-containing water is the same as in Example 1.

[0137] Table 1

[0138]

[0139] As can be seen from the phosphorus removal rate results of Examples 1 to 15 in Table 1, the phosphorus removal method using the chlorophyll-La derivative / nano-rare earth-based composite of this application has a high phosphorus removal rate. The modified calcium-magnesium mineral material used in Example 16 is an alkaline solution modified calcium-magnesium mineral material, which has a reduced phosphorus removal effect. Comparative Example 1 did not use modified calcium-magnesium mineral material as raw material for nano-rare earth-based composite, and the phosphorus removal effect was significantly reduced.

[0140] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method of synergistic dephosphorization characterized in that, The method comprises the following steps: adding a mixture of a nano-rare earth-based compound and a chlorophyll-La derivative to a phosphorus-containing pollutant, and performing light treatment to remove phosphorus; wherein the phosphorus-containing pollutant is selected from a phosphorus-containing water body or a phosphorus-containing soil; the nano-rare earth-based compound comprises nano-lanthanum oxide, nano-chitin, modified calcium-magnesium mineral material, biochar, zeolite, auxiliary material and adjusting agent; the nano-chitin comprises at least one of chitin nanocrystals, chitin nanofibers and chitin-chitosan nanocomposite fibers; the auxiliary material comprises at least one of dextrin, polyvinyl alcohol, starch, carboxymethyl cellulose and sodium alginate; the adjusting agent comprises at least one of calcium chloride, calcium sulfate, calcium nitrate, magnesium sulfate, magnesium chloride, magnesium nitrate, potassium chloride, potassium nitrate and potassium sulfate; the preparation method of the modified calcium-magnesium mineral material comprises the steps of: acid treatment of a mineral raw material, heating to 150-560 DEG C, and then pressurizing to 22-30 MPa to obtain a reaction product; the mass fraction of calcium in the mineral raw material is greater than or equal to 20%, or the mass fraction of magnesium is greater than or equal to 15%; the preparation method of the chlorophyll-La derivative comprises the following steps: mixing chlorophyll a with a first organic solvent to obtain a first mixture; the first organic solvent is selected from at least one of methanol, dichloromethane, ethanol, isopropanol, hexane and acetone; the first mixture is mixed with an acid solution to remove magnesium to obtain a second mixture; the second mixture is mixed with La2O3 and then subjected to microwave irradiation; the microwave irradiation frequency is 1000-2500 MHz, the irradiation temperature is 50-90 DEG C, and the irradiation time is 5-60 min to obtain the chlorophyll-La derivative.

2. The method of claim 1, wherein: the mass ratio of the mixture of the nano-rare earth-based compound and the chlorophyll-La derivative to the phosphorus-containing pollutant is 1: (1-5); the concentration of phosphorus in the phosphorus-containing water body is 1-20 mg / L; the concentration of phosphorus in the phosphorus-containing soil is 1-20 mg / kg; the pH value of the phosphorus-containing pollutant is 3-10; the wavelength of the light source used in the light treatment is 400-700 nm, the temperature of the light treatment is 20-80 DEG C, and the time of the light treatment is 2-10 h.

3. The method of claim 1, wherein, the preparation method of the mixture of the nano-rare earth-based compound and the chlorophyll-La derivative comprises the following steps: Method I: uniformly spraying the chlorophyll-La derivative on the surface of the nano-rare earth-based compound, and drying to obtain the mixture of the nano-rare earth-based compound and the chlorophyll-La derivative; or Method II: mechanically mixing the chlorophyll-La derivative with the nano-rare earth-based compound, and wet granulation to obtain the mixture of the nano-rare earth-based compound and the chlorophyll-La derivative.

4. The method of claim 3, wherein: The method one comprises the steps of dissolving the chlorophyll-La derivative in an organic solvent to obtain a loading liquid with a concentration of 10 mg / mL-20 mg / mL, uniformly spraying the loading liquid on the surface of the nanometer rare earth-based composite, and drying after standing and aging to obtain a mixture of the nanometer rare earth-based composite and the chlorophyll-La derivative; The organic solvent is selected from 70vol%-100vol% ethanol solution; The mass ratio of the nanometer rare earth-based composite to the chlorophyll-La derivative is 10: (1-4); In the method two, the mass ratio of the nanometer rare earth-based composite to the chlorophyll-La derivative is (8-9):(1-2).

5. The method of claim 1, wherein, The raw material components of the nanometer rare earth-based composite include, by weight fraction: 40-74 parts of nanometer lanthanum oxide, 5-46 parts of nanometer chitin, 5-26 parts of modified calcium-magnesium mineral material, 5-35 parts of biochar, 3-25 parts of zeolite, 1-9 parts of auxiliary material, and 1-5 parts of adjusting agent; The average particle size Dv50 of the nanometer lanthanum oxide is 10-100 nm, and the average particle size Dv50 of the nanometer chitin is 10-100 nm.

6. The method of claim 1, wherein, The mass-volume ratio of the chlorophyll a to the first organic solvent is 1 g:(10-50) mL; The volume ratio of the first mixture to the acid solution is 1:(1-3); the acid solution is selected from HCl solution with a concentration of 0.1 mol / L-1 mol / L, acetic acid solution with a concentration of 0.05 mol / L-0.5 mol / L, or sulfuric acid solution with a concentration of 0.5 mol / L-2 mol / L; The volume-mass ratio of the second mixture to the La2O3 is 1 mL:(0.5-2) g.

7. The method according to any one of claims 1 to 5, characterized in that, The preparation method of the chlorophyll-La derivative comprises: The biomass raw material is leached with a second organic solvent to obtain an extract containing chlorophyll a; wherein the biomass raw material includes at least one of spirulina, spinach, and silkworm excrement; and the second organic solvent is selected from at least one of dichloromethane, methanol, ethanol, isopropanol, hexane, and acetone; The extract containing chlorophyll a is mixed with a third organic solvent to obtain a third mixture, wherein the third organic solvent is a methanol solution containing 1w / v%-10w / v% sodium hydroxide; The third mixture is mixed with La2O3 and subjected to microwave irradiation, the irradiation frequency is 1000 MHz-2500 MHz, the irradiation temperature is 50℃-80℃, and the irradiation time is 10 min-60 min, and then the solid impurities are removed by filtration to obtain the chlorophyll-La derivative.

8. The method of claim 7, wherein, The mass ratio of the biomass raw material to the second organic solvent is 1:(3-20); The volume ratio of the extract containing chlorophyll a to the third organic solvent is 1:(0.5-5); The mass ratio of the biomass raw material to the La2O3 is 100:(1-10).

9. Use of the method according to any one of claims 1 to 8 for the purification of phosphorus-containing water or the remediation of phosphorus-containing soil.

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