Lanthanum-loaded nano-structure composite phosphorus removal material, nano particle size regulation and control method and application

Abstract

The invention discloses a lanthanum-loaded nano-structure composite phosphorus removal material, and belongs to the field of environmental functional materials. The lanthanum-loaded nano-structure composite phosphorus removal material comprises a polymer carrier and hydrated lanthanum oxide particles loaded in the polymer carrier, the particle size of the polymer carrier is 0.2-1mm, the average particle size of the hydrated lanthanum oxide is less than 10nm, the loading capacity of the hydrated lanthanum oxide in the lanthanum-loaded nano-structure composite phosphorus removal material is 3-20%, and the loading capacity of the hydrated lanthanum oxide in the lanthanum-loaded nano-structure composite phosphorus removal material is 3-20%. The crosslinking degree of the polymer carrier in the lanthanum-loaded nano-structure composite phosphorus removal material is 2-5%, the material can be used for adsorbing phosphate in water, and the phosphorus adsorption capacity of the material is remarkably superior to that of other materials such as an iron material and a zirconium material. Moreover, the loaded lanthanum nano-particles are small in size, but the problems that nano-materials are prone to agglomeration and inactivation, difficult to recycle and the like are solved, meanwhile, the lanthanum with the small nano-particle size can improve the specific surface area and the surface active site concentration of the lanthanum, the nano-effect is fully played, and the high adsorption capacity of phosphorus is shown.

Description

Technical Field

[0001] The present invention belongs to the field of environmental functional materials, and more specifically, relates to a lanthanum-loaded nano-structured composite phosphorus removal material, a nano-particle size regulation method and applications thereof. Background Art

[0002] Phosphorus is one of the indispensable elements for human life activities and modern agriculture. However, excessive phosphorus in water bodies can lead to eutrophication and damage the ecological environment. At present, human society is facing the dilemma of severe phosphorus resource shortage and phosphorus pollution. The in-depth treatment of phosphorus in water and the recovery of phosphorus resources have become important research topics in the field of water pollution control. The rare earth element lanthanum has a strong affinity for phosphate ions and still shows high-efficiency removal ability for phosphates even at trace levels. The specific adsorption of lanthanum to phosphorus can form lanthanum-phosphate complexes, and the pKsp of lanthanum phosphate in aqueous solution is 26.15, which is much lower than that of other metal phosphates. At present, there have been many reports on the preparation of lanthanum-loaded or modified materials. For example, in the article "Application of Phoslock(TM), an innovative phosphorus binding clay, to two Western Australian waterways: preliminary findings" published in Hydrobiologia, Volume 494 in 2003, CSIRO in Australia developed Phoslock, that is, a lanthanum-modified bentonite, but it is difficult to recycle or reuse, and there is a potential risk of lanthanum dissolution; in the article "Phosphate adsorption on lanthanum hydroxide-doped activated carbon fiber" published in Chemical Engineering Journal, Volumes 185-186 in 2012, a lanthanum-loaded fiber activated carbon ACF-LaOH was synthesized, but the loading amount and adsorption amount are limited, and it is difficult to regenerate and utilize.

[0003] Our research group has been committed to the synthesis of nano-lanthanum composites and their applications in phosphorus adsorption for many years. For example, in the prior art with the publication number CN110026169A of our research group, a polymer-based nano-lanthanum carbonate material, its preparation method, application and regeneration method are recorded. This polymer-based nano-lanthanum carbonate material is spherical particles, mainly macroporous resin spheres with nano-lanthanum carbonate particles evenly distributed in the pores. The mass fraction of lanthanum element in the polymer-based nano-lanthanum carbonate material is 10.08 - 14.3%, the crystallinity is 30 - 95%, the phosphorus adsorption capacity decreases with the increase of crystallinity, the regeneration performance increases with the increase of crystallinity, and the phosphorus adsorption rate is 24.4 - 36.5 mg / g. The polymer-based nano-lanthanum carbonate material in this prior art can be used to efficiently remove phosphorus with different concentrations in water.

[0004] Another example is that in the prior art with the publication number CN110681368A of our research group, a resin-based nano-lanthanum material, its preparation method and application are recorded. By mixing lanthanum with concentrated hydrochloric acid to form a complex anion of lanthanum and chloride ions, and uniformly adsorbing lanthanum in this form into the pores of the anion exchange resin in alcohol, and then further in-situ generating nano-scale lanthanum compounds, the prepared lanthanum oxide nanoparticles are relatively more evenly distributed and show a higher adsorption rate for phosphorus.

[0005] Another example is that in the prior art with the publication number CN110026161A of the Chinese patent application of our research group, a polymer-based nano-hydrated lanthanum oxide material, a method for regulating crystal form and crystallinity, application and regeneration method are disclosed, in which it is recorded that by the method of heating and concentrating, a concentration difference is formed inside and outside the polymer pores to load lanthanum ions; while increasing the lanthanum loading amount, the crystal form and crystallinity of the polymer-based nano-hydrated lanthanum oxide material are regulated to obtain materials with different crystal forms, crystallinities and different adsorption properties. However, this method can only regulate the crystal form and crystallinity of lanthanum, and cannot realize the regulation of the nano-particle size of lanthanum oxide in the resin-based hydrated lanthanum oxide material.

[0006] Regulating the nano-particle size of hydrated lanthanum oxide in the polymer-based hydrated lanthanum oxide material is of great significance for exploring the adsorption behavior of such materials. However, the prior art does not give a method for regulating the nano-particle size of hydrated lanthanum oxide in the polymer-based hydrated lanthanum oxide material. Therefore, it is urgent to develop a preparation method for regulating the nano-particle size of hydrated lanthanum oxide in the polymer-based hydrated lanthanum oxide material, so that researchers can controllably prepare polymer-based hydrated lanthanum oxide materials with specific nano-particle sizes of lanthanum. Summary of the Invention

[0007] 1. Problems to be Solved

[0008] In view of the technical bottleneck in the prior art that it is difficult to control the nano-particle size of hydrated lanthanum oxide in polymer-based hydrated lanthanum oxide materials, the present invention proposes an innovative solution. Specifically, the present invention provides a lanthanum-loaded nano-structured composite phosphorus-removing material, its nano-particle size control method, application and regeneration method. The core of this technology lies in the precise control of the nano-particle size of hydrated lanthanum oxide by introducing polymers with different crosslinking degrees, especially styrene-divinylbenzene copolymer spheres, in a high-concentration alcohol solution. This method not only fills the gap in the adjustment of the nano-particle size of hydrated lanthanum oxide in the prior art, but also provides a controllable and efficient way for researchers to prepare lanthanum-loaded nano-structured composite phosphorus-removing materials with specific nano-particle sizes, thus laying an important foundation for further research and application in related fields.

[0009] 2. Technical Solution

[0010] To solve the above problems, the technical solutions adopted by the present invention are as follows:

[0011] [Lanthanum-loaded Nano-structured Composite Phosphorus-removing Material]

[0012] The first aspect of the present invention provides a lanthanum-loaded nano-structured composite phosphorus-removing material, which comprises a polymer carrier and hydrated lanthanum oxide particles loaded in the polymer carrier. The particle size of the polymer carrier is 0.2 - 1 mm, the average particle size of the hydrated lanthanum oxide is below 10 nm, the loading amount of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is 3% - 20%, and the crosslinking degree of the polymer carrier in the lanthanum-loaded nano-structured composite phosphorus-removing material is 2% - 5%.

[0013] The smaller the nano-particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material, theoretically, it will increase the specific surface area of lanthanum and improve the concentration of surface active sites of lanthanum, thus being beneficial to phosphorus adsorption and removal.

[0014] As a preference of any implementation manner of the first aspect of the present invention, the polymer carrier in the lanthanum-loaded nano-structured composite phosphorus-removing material is a styrene-divinylbenzene copolymer sphere.

[0015] [Method for Controlling the Particle Size of Hydrated Lanthanum Oxide in Lanthanum-loaded Nano-structured Composite Phosphorus-removing Material]

[0016] The second aspect of the present invention provides a method for controlling the particle size of hydrated lanthanum oxide in a lanthanum-loaded nano-structured composite phosphorus-removing material, comprising the following steps:

[0017] S1 Dissolve lanthanum chloride in an alcohol solution with a mass percentage content greater than or equal to 75% to obtain a lanthanum solution;

[0018] S2 Add hydrochloric acid to the lanthanum solution and control Cl -The concentration is 0.05 - 1 mol / L, and then a polymer carrier with a cross-linking degree selected from 2% - 20% is added, and a solid mixture is obtained by filtration;

[0019] S3 Add the solid mixture to a precipitant solution, stir, and filter to obtain a lanthanum-loaded nano-structured material;

[0020] S4 Wash the lanthanum-loaded nano-structured material to neutrality, and add it to a sodium chloride solution for transformation to obtain a lanthanum-loaded nano-structured composite phosphorus removal material.

[0021] As a preference for any implementation manner of the second aspect of the present invention, in S1, the mass concentration of lanthanum chloride is 50 - 200 g / L; the alcohol solution is a methanol solution or an ethanol solution.

[0022] Crystal nucleation needs to overcome an energy barrier. The existence of this energy barrier inhibits the random generation of lanthanum nanoparticles during the reaction process. However, at high supersaturation, lanthanum will undergo explosive nucleation in a short time, and the ultra-small nanoparticles generated in this way will be relatively uniform. The swollen low-crosslinking styrene-divinylbenzene copolymer spheres mainly consist of a continuous liquid phase, which can enable the extremely fast diffusion of lanthanum ions, start rapid explosive nucleation at high supersaturation, and thus realize the generation of ultra-small nanoparticles. In other words, the flexible low-crosslinking styrene-divinylbenzene copolymer spheres have no pores themselves, and when swollen in water, swelling pores will be formed. By adding acid or alcohol, lanthanum is promoted to enter the swelling pores of the styrene-divinylbenzene copolymer spheres, and then by adding alkali, the swelling pores shrink, restricting the growth of lanthanum nanoparticles, so as to load ultra-small nanoparticle lanthanum on the styrene-divinylbenzene copolymer spheres.

[0023] During the process of preparing a lanthanum-loaded nano-structured composite phosphorus removal material using high-crosslinking styrene-divinylbenzene copolymer spheres, at low supersaturation, two or more subcritical nuclei collide and fuse, which is equivalent to a process of quickly "passing through" the energy barrier. The lanthanum nanoparticles formed in this way will continue to grow. In this case, the growth of lanthanum nanoparticles is inhibited by the cross-linked mesh pores of the styrene-divinylbenzene copolymer spheres, so as to load lanthanum with different nano particle sizes on the styrene-divinylbenzene copolymer spheres.

[0024] The purpose of adding hydrochloric acid is to greatly promote the entry of nano lanthanum into the pores of the styrene-divinylbenzene copolymer spheres. The main principle is to form LaCl4 by adding hydrochloric acid - , LaCl4 - is more likely to enter the pores of the styrene-divinylbenzene copolymer spheres through the interaction between charges.

[0025] A high-concentration alcohol solution (i.e., an alcohol aqueous solution of 75% - 100%, including a solution containing 100% alcohol) can reduce the formation of lanthanum hydrate products of macromolecules and further promote the entry of nano-lanthanum into the pore diameter of styrene-divinylbenzene copolymer spheres on the basis of adding acid. At the same time, by regulating the concentration of lanthanum chloride and the mass ratio of styrene-divinylbenzene copolymer spheres to lanthanum chloride, the loading amount of lanthanum on the styrene-divinylbenzene copolymer spheres can be controlled.

[0026] As a preference of any implementation manner of the second aspect of the present invention, in the S2, the concentration of hydrochloric acid is 0.5wt% - 4wt%; the polymer carrier is a styrene-divinylbenzene copolymer sphere, and the mass ratio of the styrene-divinylbenzene copolymer sphere to lanthanum chloride is (0.25 - 3):1; after adding the styrene-divinylbenzene copolymer sphere, the stirring time is 2 - 24h, and the stirring temperature is 25 - 70°C.

[0027] As a preference of any implementation manner of the second aspect of the present invention, in the S2: when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 2 - 5%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is below 10nm; when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 5 - 10% (excluding 5% and 10%), the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is 12 - 20nm (excluding 12nm); when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 10 - 20%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is below 12nm.

[0028] Further preferably, when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 2 - 5%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is below 7nm.

[0029] Even more preferably, when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 4%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is below 5nm; when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 8%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is 12 - 15nm (excluding 12nm); when the crosslinking degree of the styrene-divinylbenzene copolymer sphere is 15%, the average particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus-removing material is below 12nm.

[0030] As a preference of any implementation manner of the second aspect of the present invention, in the S3, the precipitant solution is 10 - 20wt% sodium hydroxide, and the mass ratio of the styrene-divinylbenzene copolymer sphere to the sodium hydroxide solution is (0.25 - 4):1;

[0031] Preferably, in any implementation manner of the second aspect of the present invention, the sodium chloride concentration in S4 is 1 wt% to 10 wt%, and the drying temperature is 50 to 80 °C.

[0032] [Application of Lanthanum-loaded Nano-structured Composite Phosphorus-removing Material in Removing Phosphate in Water Body]

[0033] The third aspect of the present invention provides the application of a lanthanum-loaded nano-structured composite phosphorus-removing material provided by the first aspect of the present invention or a lanthanum-loaded nano-structured composite phosphorus-removing material obtained by the particle size regulation method provided by the second aspect of the present invention in removing phosphate in water body, including the following steps: adding the lanthanum-loaded nano-structured composite phosphorus-removing material into the water body, adjusting the pH value of the water body to 6 to 8, and the oscillation reaction time is greater than or equal to 24 h.

[0034] Preferably, in any implementation manner of the third aspect of the present invention, when the crosslinking degree of the styrene-divinylbenzene copolymer sphere in the lanthanum-loaded nano-structured composite phosphorus-removing material is 10% to 20%, the first adsorption amount of phosphorus by the lanthanum-loaded nano-structured composite phosphorus-removing material is 200 to 280 mg / g (P / La), and the treatment capacity for the phosphorus-containing water body is 1500 BV to 5000 BV; when the crosslinking degree of the styrene-divinylbenzene copolymer sphere in the lanthanum-loaded nano-structured composite phosphorus-removing material is 2% to 5%, the first adsorption amount of phosphorus by the lanthanum-loaded nano-structured composite phosphorus-removing material is 280 to 320 mg / g (P / La), and the treatment capacity for the phosphorus-containing water body is 5000 BV to 10000 BV.

[0035] The lanthanum-loaded nano-structured composite phosphorus-removing material with a lanthanum nano-particle size of 3 nm has the highest first adsorption amount of phosphorus. After desorption, its performance decreases slightly, but it can still maintain a stable adsorption amount. At the same time, its treatment capacity for polluted water body is as high as 7500 BV, far exceeding the 2000 BV treatment capacity of the lanthanum-loaded nano-structured composite phosphorus-removing material with 10 nm lanthanum. By regulating the nano-particle size of lanthanum in the lanthanum-loaded nano-structured composite phosphorus-removing material, its treatment capacity for polluted water body is significantly improved.

[0036] Preferably, in any implementation manner of the third aspect of the present invention, the regeneration method of the lanthanum-loaded nano-structured composite phosphorus-removing material after adsorbing phosphorus includes the following steps:

[0037] Step a: adding the lanthanum-loaded nano-structured composite phosphorus-removing material after adsorbing phosphorus into a 5 wt% to 15 wt% NaOH solution, with a solid-liquid ratio of 1 to 20 g / L, heating and oscillating the reaction time for greater than or equal to 24 h;

[0038] Step b: adding the desorbed lanthanum-loaded nano-structured composite phosphorus-removing material into a 1 wt% to 5 wt% sodium chloride solution, stirring for transformation and then filtering out;

[0039] Step c: Wash the lanthanum-loaded nano-structured composite phosphorus removal material after filtration with ultrapure water, and dry it at 50-80 °C after filtration.

[0040] 3. Beneficial effects

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) The present invention for the first time prepares a lanthanum-loaded nano-structured composite phosphorus removal material with a particle size of 0.2-1 mm, wherein the average nano-particle size of lanthanum is less than 10 nm. The loading amount of lanthanum in the lanthanum-loaded nano-structured composite phosphorus removal material is 3%-20%, and the crosslinking degree of the polymer carrier in the lanthanum-loaded nano-structured composite phosphorus removal material is 2%-5%. This material can be used to adsorb phosphate in water, and its phosphorus adsorption ability is significantly better than other materials such as iron-based and zirconium-based materials. In particular, it can be seen from the TEM of the material prepared in the examples that the nano-particle size of lanthanum in the lanthanum-loaded nano-structured composite phosphorus removal material of the present invention is less than 10 nm. There is no literature report in the prior art on a lanthanum-loaded nano-structured composite phosphorus removal material with a lanthanum nano-particle size of less than 10 nm. This result is a major progress in this field.

[0043] (2) The method for regulating the particle size of hydrated lanthanum oxide in the lanthanum-loaded nano-structured composite phosphorus removal material provided by the present invention adopts different lanthanum loading methods. In the prior art, the method of thermal concentration is mostly used to load lanthanum into the resin pores, while the present invention uses the conditions of high-concentration alcohol and the addition of hydrochloric acid to promote the loading of lanthanum into the pores of styrene-divinylbenzene copolymer spheres. Specifically, in a high-concentration alcohol solution, the formation of large-molecule lanthanum hydrate products can be reduced, which helps lanthanum to enter the small pores of styrene-divinylbenzene copolymer spheres. At the same time, the addition of hydrochloric acid can promote the formation of LaCl4 - , LaCl4 - The interaction of charges between LaCl4 and styrene-divinylbenzene copolymer spheres further promotes the entry of lanthanum into the pores of styrene-divinylbenzene copolymer spheres, thereby loading lanthanum onto styrene-divinylbenzene copolymer spheres. Moreover, the loading amount of lanthanum can be controlled by regulating the concentration of lanthanum chloride and the mass ratio of styrene-divinylbenzene copolymer spheres to lanthanum chloride.

[0044] (3) The present invention controls the nano-particle size of lanthanum hydroxide in the lanthanum-loaded nano-structured composite phosphorus-removing material by using the principle of "precursor introduction - burst nucleation" or "precursor introduction - mesoporous confinement nucleation" respectively. The low cross-linked styrene-divinylbenzene copolymer spheres use the principle of "precursor introduction - burst nucleation" to load lanthanum with a particle size below 10 nm. The main principle is that crystal nucleation needs to overcome an energy barrier, and the existence of this energy barrier inhibits the random generation of lanthanum nanoparticles during the reaction process. However, under high supersaturation, lanthanum will undergo burst nucleation in a short time, and the generated ultra-small nanoparticles will be relatively uniform. The swollen low cross-linked styrene-divinylbenzene copolymer spheres mainly consist of a continuous liquid phase, which can enable the rapid diffusion of lanthanum ions and start rapid burst nucleation at high supersaturation, thus realizing the generation of ultra-small nanoparticles. Specifically, when the flexible low cross-linked styrene-divinylbenzene copolymer spheres without pores are put into water to swell, swelling pores will be formed. By adding acid or alcohol, lanthanum is promoted to enter the swelling pores of the styrene-divinylbenzene copolymer spheres, and then by adding alkali, the swelling pores shrink, restricting the growth of lanthanum nanoparticles, so as to load ultra-small nanoparticle lanthanum hydroxide on the styrene-divinylbenzene copolymer spheres.

[0045] In the process of preparing the lanthanum-loaded nano-structured composite phosphorus-removing material by using the principle of "precursor introduction - mesoporous confinement nucleation" with high cross-linked styrene-divinylbenzene copolymer spheres, under low supersaturation, two or more subcritical nuclei collide and fuse, which is equivalent to a process of quickly "crossing" the energy barrier. In this way, the formed lanthanum nanoparticles will continue to grow. In this case, the cross-linked pores of the styrene-divinylbenzene copolymer spheres inhibit the growth of lanthanum nanoparticles, so as to load lanthanum hydroxide with different nano-particle sizes by controlling the cross-linking degree of the styrene-divinylbenzene copolymer spheres.

[0046] However, the heating conditions in the thermal concentration method often used in the prior art will seriously affect the pore space inside the styrene-divinylbenzene copolymer spheres, making the size of the pore space extremely uneven, so that lanthanum hydroxide with a uniform and controllable particle size cannot be obtained.

[0047] The size of the loaded lanthanum nanoparticles is small, which solves the problems such as easy agglomeration and inactivation and difficult recovery of nano-materials. At the same time, the smaller nano-particle size of lanthanum will increase the specific surface area and the concentration of surface active sites of lanthanum, giving full play to the nano-effect, showing a high phosphorus adsorption capacity, and also significantly improving the treatment ability for polluted water bodies.

[0048] (4) There are obvious differences in the phosphorus adsorption capacity of the lanthanum-loaded nano-structured composite phosphorus-removing materials loaded with lanthanum hydroxide with different particle sizes, and the regeneration performance is also different. From Figure 8 to Figure 10It can be seen that the lanthanum-loaded nano-structured composite phosphorus removal material with the smallest lanthanum nano-particle size has the highest initial phosphorus adsorption capacity. After desorption, its performance decreases slightly, but it can still maintain a stable adsorption capacity. At the same time, the lanthanum-loaded nano-structured composite phosphorus removal material with the smallest lanthanum nano-particle size has a treatment capacity of up to 7500 BV for polluted water bodies, far exceeding the 2000 BV treatment capacity of the lanthanum-loaded nano-structured composite phosphorus removal material with 10-nm lanthanum. Therefore, according to the actual situation, by controlling the lanthanum nano-particle size in the preparation process, lanthanum-loaded nano-structured composite phosphorus removal materials with different lanthanum nano-particle sizes can be provided to achieve the high efficiency and economy of the nano-composite material.

[0049] (5) The process flow of the present invention is simple, reasonably designed, easy to manufacture, and suitable for the industrial promotion and application of lanthanum adsorption and phosphorus removal in polluted water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is the process flow chart of the preparation method of the present invention;

[0051] Figure 2a is the TEM image of the 8%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@1 prepared in Example 1 of the present invention;

[0052] Figure 2b is the particle size distribution diagram of the 8%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@1 prepared in Example 1 of the present invention

[0053] Figure 3 is the XRD pattern of the 8%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@1 prepared in Example 1 of the present invention;

[0054] Figure 4a is the TEM image of the 4%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@2 prepared in Example 2 of the present invention;

[0055] Figure 4b is the particle size distribution diagram of the 4%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@2 prepared in Example 2 of the present invention;

[0056] Figure 5 is the XRD pattern of the 4%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@2 prepared in Example 2 of the present invention;

[0057] Figure 6a is the TEM image of the 15%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@3 prepared in Example 3 of the present invention;

[0058] Figure 6b is the particle size distribution diagram of the 15%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material La@3 prepared in Example 3 of the present invention;

[0059] Figure 7 XRD pattern of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with 15% crosslinking degree prepared in Example 3 of the present invention;

[0060] Figure 8a TEM image of the lanthanum-loaded nano-structured composite phosphorus removal material La@4 with 4% crosslinking degree prepared in Example 4 of the present invention;

[0061] Figure 8b Particle size distribution diagram of the lanthanum-loaded nano-structured composite phosphorus removal material La@4 with 4% crosslinking degree prepared in Example 4 of the present invention;

[0062] Figure 9 XRD pattern of the lanthanum-loaded nano-structured composite phosphorus removal material La@4 with 4% crosslinking degree prepared in Example 4 of the present invention;

[0063] Figure 10 Effect of five-cycle adsorption and desorption of the lanthanum-loaded nano-structured composite phosphorus removal material La@1 with 8% crosslinking degree prepared in Example 1 of the present invention in the presence of interfering ions;

[0064] Figure 11 Effect of five-cycle adsorption and desorption of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with 4% crosslinking degree prepared in Example 2 of the present invention in the presence of interfering ions;

[0065] Figure 12 Effect of five-cycle adsorption and desorption of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with 15% crosslinking degree prepared in Example 3 of the present invention in the presence of interfering ions;

[0066] Figure 13 Column adsorption effect of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with 4% crosslinking degree prepared in Example 2 of the present invention;

[0067] Figure 14 Column adsorption effect of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with 15% crosslinking degree prepared in Example 3 of the present invention. Detailed implementation manners

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs; the term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0069] For those not specified in the examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0070] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. A person skilled in the art can readily determine the degree of flexibility for a specific variable.

[0071] Concentrations, amounts, and other numerical data may be presented herein in a range format. It should be understood that such range formats are used merely for convenience and brevity and should be interpreted flexibly as including not only the numerical values explicitly recited as the limits of the range but also all individual numerical values or sub-ranges subsumed within that range as if each numerical value and sub-range were explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted as including not only the explicitly recited limits of 1 to about 4.5 but also the individual numbers (such as 2, 3, 4) and sub-ranges (such as 1 to 3, 2 to 4, etc.). The same principle applies to ranges reciting only one numerical value, such as "less than about 4.5", which should be interpreted as including all of the above values and ranges. Moreover, this interpretation should apply regardless of the breadth of the range or feature being described.

[0072] The present invention will be further described below in conjunction with specific embodiments.

[0073] Preparation materials:

[0074] LaCl3·7H2O, ethanol, sodium hydroxide, and NaCl were purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd.; styrene-divinylbenzene copolymer spheres with 4% crosslinking degree, 8% crosslinking degree, and 15% crosslinking degree were purchased from Zhejiang Zhengguang Industry Co., Ltd.

[0075] Ethanol, sodium hydroxide, and NaCl were prepared into the required concentrations as needed.

[0076] Example 1

[0077] This example is a method for preparing a lanthanum-loaded nano-structured composite phosphorus removal material with an 8% crosslinking degree using the process flow shown as follows: Figure 1 The specific steps are as follows:

[0078] 1) Add 5 g of LaCl3·7H2O to 100 mL of 75% aqueous ethanol solution, seal and stir at 60 °C to dissolve to obtain a lanthanum solution;

[0079] 2) Add 2 mL of 2 wt% hydrochloric acid solution to the lanthanum solution, and the concentration of Cl- in water is about 0.04 mol / L;

[0080] 3) Slowly add 10 g of styrene-divinylbenzene copolymer spheres with an 8% crosslinking degree to the lanthanum solution prepared in step 2), and stir for 6 h until the reaction system is mixed evenly to obtain a solid-liquid mixture;

[0081] 4) Filter the solid-liquid mixture obtained in step 3) until there is no liquid residue on the surface to obtain a solid mixture;

[0082] 5) Add the solid mixture obtained in step 4) to a 15 wt% sodium hydroxide solution and stir for 6 h. The mass ratio of the solid mixture to the sodium hydroxide solution is 0.4:1;

[0083] 6) Filter the mixture obtained in step 5), wash it with pure water until neutral, then add it to a 2% NaCl solution, stir, filter out and dry to obtain a lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 8%, named La@1.

[0084] The lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 8% prepared in this example is in the form of white round particles with an average particle size of 0.4 - 0.7 mm. After digestion, the loading amount of lanthanum is measured by an inductively coupled plasma optical emission spectrometer (ICP-OES) to be about 18.7%, indicating that lanthanum is successfully loaded. The transmission electron microscope (TEM) image of La@1 is as Figure 2a shown. Lanthanum is distributed on the surface of the styrene-divinylbenzene copolymer sphere material carrier in the form of nano-particles. The particle size distribution of La@1 is as Figure 2b shown. The particle size of La nano-particles is mainly distributed in the range of 6 - 26 nm. Using ImageJ statistics, the average particle size is about 14.36 nm. X-ray diffraction (XRD) test analysis of La@1 is carried out, and the results are as Figure 3 shown. Lanthanum exists in the form of La(OH)3.

[0085] Test Example 1

[0086] This test example is to test the adsorption and desorption effects of the lanthanum-loaded nano-structured composite phosphorus removal material La@1 with a crosslinking degree of 8% prepared in Test Example 1 on phosphate in water under interference ion conditions. The specific process is as follows:

[0087] 1) Prepare a mixed solution containing P and SO4 2- simultaneously, control the concentration of P to be 100 mg / L, and the concentration of the interference ion SO4 2- to be 500 mg / L. At the same time, control the initial pH of the mixed solution to be 7.0;

[0088] 2) Control the dosing concentration of the material La@1 in the mixed solution to be 0.5 g / L, stir and adsorb at room temperature for 24 h, then take the supernatant to measure the concentration of P, and calculate the adsorption amount of P;

[0089] 3) Add the adsorbed material La@1 to a 10% NaOH solution, stir and desorb at room temperature for 24 h, then take the supernatant to measure the concentration of P, and calculate the desorption amount of P;

[0090] 4) Add the desorbed material La@1 to a 2% NaCl solution, stir at room temperature, and carry out transformation;

[0091] 5) Repeat steps 1) to 4) for a total of 5 times to test the adsorption and desorption of phosphate in water.

[0092] The effect of the lanthanum-loaded nano-structured composite phosphorus removal material La@1 with 8% cross-linking degree on the adsorption and desorption of phosphate in water under interference ion conditions for 5 times is shown in Figure 8. The first adsorption capacity of the material La@1 is 250 mg / g (P / La). After desorption, it can still be used continuously, but its performance decreases slightly.

[0093] Example 2

[0094] This example is a method for preparing a lanthanum-loaded nano-structured composite phosphorus removal material with 4% cross-linking degree using the process flow as Figure 1 shown. The specific steps are as follows:

[0095] 1) Add 10 g of LaCl3·7H2O to 100 mL of 75% ethanol aqueous solution, seal and stir at 60 °C to dissolve to obtain a lanthanum solution;

[0096] 2) Add 1 mL of 2 wt% hydrochloric acid solution to the lanthanum solution, and the concentration of Cl- in water is about 0.08 mol / L;

[0097] 3) Slowly add 7 g of styrene-divinylbenzene copolymer spheres with a cross-linking degree of 4% to the lanthanum solution prepared in step 1), and stir for 6 h until the reaction system is mixed evenly to obtain a solid-liquid mixture;

[0098] 4) Filter the solid-liquid mixture obtained in step 3) until there is no liquid residue on the surface to obtain a solid mixture;

[0099] 5) Add the solid mixture obtained in step 4) to a 15 wt% sodium hydroxide solution and stir for 6 h. The mass ratio of the solid mixture to the sodium hydroxide solution is 0.4:1;

[0100] 6) Filter the mixture obtained in step 5), wash it with pure water until neutral, then add it to a 2% NaCl solution, stir, filter out and dry it to obtain a lanthanum-loaded nano-structured composite phosphorus removal material with 4% cross-linking degree, named La@2.

[0101] The 4%-crosslinked lanthanum-loaded nano-structured composite phosphorus removal material prepared in this example is in the form of yellow transparent round particles, with an average particle size of 0.4 - 0.8 mm. After digestion, the lanthanum loading amount is measured to be about 9.2% by inductively coupled plasma optical emission spectrometer (ICP-OES), indicating that lanthanum is successfully loaded. The transmission electron microscope (TEM) image of La@2 is as Figure 4aAs shown, lanthanum is distributed on the surface of the styrene-divinylbenzene copolymer sphere material carrier in the form of nanoparticles. The particle size distribution of La@2 is as Figure 4b shown. The particle size of La nanoparticles is mainly distributed in the range of 2 - 5 nm. It can be statistically known by ImageJ that the average particle size is about 3.56 nm. X-ray diffraction (XRD) test analysis was carried out on La@2, and the results are as Figure 5 shown. Lanthanum exists in the form of La(OH)3.

[0102] Test Example 2

[0103] This test example is to test the adsorption and desorption effects of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with a 4% cross-linking degree prepared in Test Example 2 on phosphate in water under the condition of interfering ions. The specific process is as follows:

[0104] 1) Prepare a mixed solution containing P and SO4 2- simultaneously, control the concentration of P to be 100 mg / L, and the concentration of the interfering ion SO4 2- to be 500 mg / L. At the same time, control the initial pH of the mixed solution to be 7.0;

[0105] 2) Control the dosing concentration of the material La@2 in the mixed solution to be 0.5 g / L, stir and adsorb at room temperature for 24 h, then take the supernatant to measure the concentration of P, and calculate the adsorption amount of P;

[0106] 3) Add the adsorbed material La@2 to 10% NaOH solution, heat to 60 °C and stir for desorption for 24 h, then take the supernatant to measure the concentration of P, and calculate the desorption amount of P;

[0107] 4) Add the desorbed material La@2 to 2% NaCl solution and stir at room temperature for transformation;

[0108] 5) Repeat steps 1) to 4) for a total of 5 times to test the adsorption and desorption of phosphate in water.

[0109] The effects of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with a 4% cross-linking degree on the adsorption and desorption of phosphate in water 5 times under the condition of interfering ions are as Figure 9 shown. The first adsorption amount of the material La@2 is 289 mg / g (P / La). It can still be used after desorption, but the performance decreases slightly.

[0110] Test Example 3

[0111] This test example is to test the performance of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with a 4% cross-linking degree prepared in Test Example 2 under actual application conditions. The specific process is as follows:

[0112] 1) Prepare a solution with a P concentration of 1 mg / L as the target treatment water body. The solution also contains 150 mg / L of SO4 2- , 150 mg / L of Cl - and 100 mg / L of NO3 - as competing ions;

[0113] 2) Take 5 mL of the wet volume of the material La@2 as the column for column adsorption, and control the water flux to be 20 BV / h to adsorb and remove phosphorus (P) in the target treatment water body;

[0114] 3) Sampling is carried out at intervals of every 10 BV, and the phosphorus concentration of the effluent is measured.

[0115] The performance of the lanthanum-loaded nano-structured composite phosphorus removal material La@2 with a 4% crosslinking degree under actual application conditions is as Figure 11 shown. At a flow rate of 20 BV / h, the material La@2 can treat approximately 7500 BV of the target treatment water body, showing high application potential.

[0116] Example 3

[0117] This example is a method for preparing a lanthanum-loaded nano-structured composite phosphorus removal material with a 15% crosslinking degree using the process flow as Figure 1 shown. The specific steps are as follows:

[0118] 1) Add 5 g of LaCl3·7H2O to 100 mL of 75% ethanol aqueous solution, seal and stir to dissolve at 60 °C to obtain a lanthanum solution;

[0119] 2) Add 2 mL of 2 wt% hydrochloric acid solution to the lanthanum solution, and the concentration of Cl- in the water is about 0.04 mol / L;

[0120] 3) Slowly add 7 g of styrene-divinylbenzene copolymer spheres with a crosslinking degree of 15% to the lanthanum solution prepared in step 1), and stir for 6 h until the reaction system is mixed evenly to obtain a solid-liquid mixture;

[0121] 4) Filter the solid-liquid mixture obtained in step 3) until there is no liquid residue on the surface to obtain a solid mixture;

[0122] 5) Add the solid mixture obtained in step 4) to 15 wt% sodium hydroxide solution and stir for 6 h. The mass ratio of the solid mixture to the sodium hydroxide solution is 0.4:1;

[0123] 6) Filter the mixture obtained in step 5), wash it with pure water until it is neutral, then add it to 2% NaCl solution, stir, filter out and dry it to obtain a lanthanum-loaded nano-structured composite phosphorus removal material with a 15% crosslinking degree, named La@3.

[0124] The prepared lanthanum-loaded nano-structured composite phosphorus removal material with a 15% cross-linking degree in this example is in the form of yellow round particles, with an average particle size of 0.3 - 0.8 mm. After digestion, the lanthanum loading amount is measured to be about 11% by inductively coupled plasma optical emission spectrometer (ICP-OES), indicating that lanthanum is successfully loaded. The transmission electron microscope (TEM) image of La@3 is as Figure 6a shown, and lanthanum is distributed on the surface of the styrene-divinylbenzene copolymer sphere material carrier in the form of nano-particles. The particle size distribution of La@3 is as Figure 6b shown. The particle size of La nano-particles is mainly distributed in the range of 6 - 16 nm. Using ImageJ statistics, the average particle size is about 10.66 nm. X-ray diffraction (XRD) test analysis of La@3 is carried out, and the results are as Figure 7 shown, and lanthanum exists in the form of La(OH)3.

[0125] Test Example 4

[0126] This test example is to test the adsorption and desorption effects of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with a 15% cross-linking degree prepared in Test Example 3 on phosphate in water under the condition of interfering ions. The specific process is as follows:

[0127] 1) Prepare a mixed solution containing both P and SO4 2- , control the concentration of P to be 100 mg / L, the concentration of the interfering ion SO4 2- to be 500 mg / L, and at the same time control the initial pH of the mixed solution to be 7.0;

[0128] 2) Control the dosing concentration of the material La@3 in the mixed solution to be 0.5 g / L, stir and adsorb at room temperature for 24 h, then take the supernatant to measure the concentration of P, and calculate the adsorption amount of P;

[0129] 3) Add the adsorbed material La@3 to 10% NaOH solution, heat to 60 °C and stir for desorption for 24 h, then take the supernatant to measure the concentration of P, and calculate the desorption amount of P;

[0130] 4) Add the desorbed material La@3 to 2% NaCl solution and stir at room temperature for transformation;

[0131] 5) Repeat steps 1) to 4) for a total of 5 times to test the adsorption and desorption of phosphate in water.

[0132] The effects of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with a 15% cross-linking degree on the adsorption and desorption of phosphate in water 5 times under the condition of interfering ions are as Figure 10 shown. The first adsorption amount of the material La@2 is 254 mg / g (P / La), and it can still maintain a stable adsorption amount after desorption, but the performance decreases slightly.

[0133] Test Example 5

[0134] This test example is to test the performance of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with a crosslinking degree of 15% prepared in Test Example 3 under actual application conditions. The specific process is as follows:

[0135] 1) Prepare a solution with a P concentration of 1 mg / L as the target treatment water body, and the solution also contains 150 mg / L of SO4 2- , 150 mg / L of Cl - and 100 mg / L of NO3 - as competing ions;

[0136] 2) Take 5 mL of the wet volume of the material La@3 as the column for column adsorption, and control the water flux to be 20 BV / h to adsorb and remove phosphorus (P) in the target treatment water body;

[0137] 3) Sampling is carried out at intervals of every 10 BV and the phosphorus concentration of the effluent is measured.

[0138] The performance of the lanthanum-loaded nano-structured composite phosphorus removal material La@3 with a crosslinking degree of 15% under actual application conditions is as Figure 12 shown. At a flow rate of 20 BV / h, the material La@3 can treat approximately 2000 BV of the target treatment water body and has high application potential.

[0139] Example 4

[0140] This example is a method for preparing a lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 4% by using the process flow shown as Figure 1 below. The specific steps are as follows:

[0141] 1) Add 12 g of LaCl3·7H2O to 100 mL of 85% ethanol aqueous solution, seal and stir to dissolve at 60 °C to obtain a lanthanum solution;

[0142] 2) Add 1 mL of 2 wt% hydrochloric acid solution to the lanthanum solution, and the concentration of Cl- in water is about 0.1 mol / L;

[0143] 3) Slowly add 7 g of styrene-divinylbenzene copolymer spheres with a crosslinking degree of 4% to the lanthanum solution prepared in step 2), and stir for 6 h until the reaction system is mixed evenly to obtain a solid-liquid mixture;

[0144] 4) Filter the solid-liquid mixture obtained in step 3) until there is no liquid residue on the surface to obtain a solid mixture;

[0145] 5) Add the solid mixture obtained in step 4) to 15 wt% sodium hydroxide solution and stir for 6 h. The mass ratio of the solid mixture to the sodium hydroxide solution is 0.5:1;

[0146] 6) Filter the mixture obtained in step 5), wash it with pure water until neutral, then add it to a 2% NaCl solution, stir, filter out and dry to obtain a lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 4%, named La@4.

[0147] The lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 4% prepared in this example is in the form of yellow transparent round particles, with an average particle size of 0.4 - 0.8 mm. After digestion, the lanthanum loading amount is measured to be about 14.3% by inductively coupled plasma optical emission spectrometer (ICP-OES), indicating that lanthanum is successfully loaded. The transmission electron microscope (TEM) image of La@4 is as Figure 8a shown. Lanthanum is distributed on the surface of the styrene-divinylbenzene copolymer sphere material carrier in the form of nano-particles. The particle size distribution of La@4 is as Figure 8b shown. The particle size of La nano-particles is mainly distributed in the range of 3 - 9 nm. It can be statistically known by ImageJ that the average particle size is about 5.41 nm. X-ray diffraction (XRD) test analysis is carried out on La@4, and the results are as Figure 9 shown. Lanthanum exists in the form of La(OH)3.

[0148] Comparative Example 1

[0149] This example is a method for preparing a lanthanum-loaded nano-structured composite phosphorus removal material with a crosslinking degree of 4% by using the process flow as Figure 1 shown. The specific steps are as follows:

[0150] 1) Add 10 g of LaCl3·7H2O to 100 mL of 20% ethanol aqueous solution, seal and stir to dissolve at 60 °C to obtain a lanthanum solution;

[0151] 2) Add 1 mL of 2 wt% hydrochloric acid solution to the lanthanum solution, and the concentration of Cl- in water is about 0.1 mol / L;

[0152] 3) Slowly add 7 g of styrene-divinylbenzene copolymer spheres with a crosslinking degree of 4% to the lanthanum solution prepared in step 2), and stir for 6 h until the reaction system is mixed evenly to obtain a solid-liquid mixture;

[0153] 4) Filter the solid-liquid mixture obtained in step 3) until there is no liquid residue on the surface to obtain a solid mixture;

[0154] 5) Add the solid mixture obtained in step 4) to a 15 wt% sodium hydroxide solution and stir for 6 h. The mass ratio of the solid mixture to the sodium hydroxide solution is 0.5:1;

[0155] 6) Filter the mixture obtained in step 5), wash it with pure water until neutral, then add it to a 2% NaCl solution, stir, filter out and dry to obtain a lanthanum-loaded nano-structured composite phosphorus removal material with a cross-linking degree of 4%, named La@5.

[0156] The lanthanum-loaded nano-structured composite phosphorus removal material with a cross-linking degree of 4% prepared in this example is in the form of yellow transparent round particles, with an average particle size of 0.4 - 0.8 mm. After digestion, the lanthanum loading amount is measured by an inductively coupled plasma optical emission spectrometer (ICP-OES) to be about 3.8%, indicating poor lanthanum loading.

[0157] The above content is a schematic description of the present invention and its implementation manners. This description is not restrictive. What is shown in the embodiments is only one of the implementation manners of the present invention, and the actual implementation manners are not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar implementation manners and embodiments without creative efforts without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A lanthanum-loaded nanostructured composite phosphorus removal material, characterized in that: The lanthanum-loaded milli-nanostructure composite phosphorus removal material comprises a polymer carrier and hydrated lanthanum oxide particles loaded in the polymer carrier, the particle size of the polymer carrier is 0.2-1 mm, the average particle size of the hydrated lanthanum oxide is below 10 nm, the loading amount of the hydrated lanthanum oxide in the lanthanum-loaded milli-nanostructure composite phosphorus removal material is 3% to 20%, and the cross-linking degree of the polymer carrier in the lanthanum-loaded milli-nanostructure composite phosphorus removal material is 2% to 5%.

2. The lanthanum-loaded nanostructured composite phosphorus removal material according to claim 1, characterized in that: The polymer carrier in the lanthanum-loaded milli-nanostructure composite phosphorus removal material is a styrene-divinylbenzene copolymer sphere.

3. A method for controlling the particle size of hydrated lanthanum oxide in a lanthanum-loaded nanostructured composite phosphorus removal material, characterized in that: The following steps are involved: S1 dissolving lanthanum chloride in an alcohol solution having a mass percentage content of 75% or more to obtain a lanthanum solution; S2 adds hydrochloric acid to the lanthanum solution to control Cl - The concentration of the mixture is 0.05 to 1 mol / L, and a polymer carrier selected from a cross-linking degree of 2% to 20% is added, and a solid mixture is obtained by filtering; S3 adding the solid mixture to a precipitant solution, stirring, and filtering to obtain a lanthanum-loaded millinanostructure material; S4: washing the lanthanum-carrying milli-nanostructured material to neutrality, adding it into a sodium chloride solution for transformation to obtain a lanthanum-carrying milli-nanostructured composite phosphorus removal material.

4. The method for controlling the particle size of hydrated lanthanum oxide in the lanthanum-loaded milli-nanostructured composite phosphorus removal material according to claim 3, characterized in that: In S1: The mass concentration of lanthanum chloride is 50-200 g / L; and / or The alcohol solution is a methanol solution or an ethanol solution.

5. The method for controlling the particle size of hydrated lanthanum oxide in the lanthanum-loaded milli-nanostructured composite phosphorus removal material according to claim 4, characterized in that: In S2: The hydrochloric acid concentration is 0.5wt% to 4wt%; and / or The polymer carrier is styrene-divinylbenzene copolymer spheres, and the mass ratio of styrene-divinylbenzene copolymer spheres to lanthanum chloride is (0.25-3):1; after adding the styrene-divinylbenzene copolymer spheres, the stirring time is 2-24 hours and the stirring temperature is 25-70°C.

6. The method for controlling the particle size of hydrated lanthanum oxide in the lanthanum-carrying milli-nanostructure composite phosphorus removal material according to claim 5, characterized in that: In S2: When the crosslinking degree of the styrene-divinylbenzene copolymer spheres is 2% to 5%, the average particle size of the hydrated lanthanum oxide in the obtained lanthanum-supported nanostructured composite phosphorus removal material is less than 10 nm; When the crosslinking degree of the styrene-divinylbenzene copolymer spheres is 5% to 10%, excluding 5% and 10%, the average particle size of the hydrated lanthanum oxide in the lanthanum-supported nanostructured composite phosphorus removal material is 12 to 20 nm, excluding 12 nm; When the cross-linking degree of the styrene-divinylbenzene copolymer spheres is 10% to 20%, the average particle size of the hydrated lanthanum oxide in the lanthanum-carrying milli-nano structure composite phosphorus removal material is less than 12 nm.

7. The method for controlling the particle size of hydrated lanthanum oxide in the lanthanum-carrying milli-nanostructure composite phosphorus removal material according to claim 6, characterized in that: In S2: When the cross-linking degree of the styrene-divinylbenzene copolymer spheres is 4%, the average particle size of the hydrated lanthanum oxide in the obtained lanthanum-carrying milli-nano structure composite phosphorus removal material is less than 5nm; When the cross-linking degree of the styrene-divinylbenzene copolymer spheres is 8%, the average particle size of the hydrated lanthanum oxide in the lanthanum-supported nanostructured composite phosphorus removal material is 12 to 15 nm, excluding 12 nm; When the cross-linking degree of the styrene-divinylbenzene copolymer spheres is 15%, the average particle size of the hydrated lanthanum oxide in the lanthanum-carrying milli-nano structure composite phosphorus removal material is less than 12 nm.

8. The method for controlling the particle size of hydrated lanthanum oxide in the lanthanum-carrying milli-nanostructure composite phosphorus removal material according to claim 7, characterized in that: In the S3: The precipitant solution is 10-20wt% sodium hydroxide; The mass ratio of the styrene-divinylbenzene copolymer spheres to the sodium hydroxide solution is (0.25-4):1; In S4: The concentration of sodium chloride is 1wt% to 10wt%.

9. Use of the lanthanum-loaded milli-nanostructured composite phosphorus removal material according to claim 1 or 2, or the lanthanum-loaded milli-nanostructured composite phosphorus removal material obtained by the particle size control method according to any one of claims 3 to 8, in removing phosphate from water, characterized in that: The following steps are involved: Add lanthanum-loaded milli-nanostructured composite phosphorus removal material to the water body, adjust the pH value of the water body to 6-8, and the oscillation reaction time is greater than or equal to 24 hours.

10. The use according to claim 9, characterized in that: When the cross-linking degree of styrene-divinylbenzene copolymer spheres in the lanthanum-loaded milli-nano structure composite phosphorus removal material is 10-20%, the initial adsorption amount of phosphorus by the lanthanum-loaded milli-nano structure composite phosphorus removal material is 200-280 mg / g (P / La), and the treatment capacity of phosphorus-containing water is 1500 BV-2500 BV; When the cross-linking degree of styrene-divinylbenzene copolymer spheres in the lanthanum-loaded milli-nanostructured composite phosphorus removal material is 2-5%, the initial adsorption amount of phosphorus by the lanthanum-loaded milli-nanostructured composite phosphorus removal material is 280-320 mg / g (P / La), and the treatment capacity for phosphorus-containing water is 5000BV-8000BV.

Images