Phosphorus-fixing lanthanum-based nano composite material as well as preparation method and application thereof

Abstract

The invention provides a phosphorus-fixing lanthanum-based nano composite material as well as a preparation method and application thereof, and relates to the field of novel nano composite materials. According to the material, lysozyme protein fibers are taken as a structural template, a confinement space is constructed by utilizing the ultrahigh length-diameter ratio of the lysozyme protein fibers, and controllable synthesis of the sub-5nm high-dispersion lanthanum oxide nanoparticles is realized. Functional groups in a protein chain can be enriched and nucleation sites can be provided through electrostatic attraction and key coordination synergistic effect, so that the lanthanum-based protein fiber nano composite material is formed. When the material is used for treating phosphorus wastewater, efficient phosphorus removal and long-term phosphorus fixation are realized through an enrichment-conversion synergistic mechanism: phosphate ions are enriched through electrostatic adsorption, and thermodynamically stable lanthanum phosphate is generated in situ at lanthanum active sites. According to the method, gt is still kept in the presence of high-concentration equal competitive ions; the phosphorus removal rate is 90%, the generated lanthanum phosphate can be used as a slow-release phosphate fertilizer or an industrial phosphorus chemical raw material, and closed-loop conversion from pollution purification to resource utilization is realized.

Description

Technical Field

[0001] This invention application relates to the field of novel nanocomposite materials, specifically to a phosphorus-fixed lanthanum-based nanocomposite material, its preparation method, and its application. Background Technology

[0002] Eutrophication is a major global water environment problem, rooted in the excessive input of nutrients, especially phosphorus. As a crucial element essential for life, phosphorus, when its concentration exceeds the water body's self-purification capacity, can trigger severe consequences such as algal blooms, dissolved oxygen depletion, and imbalances in aquatic ecosystems. Therefore, developing efficient and economical deep phosphorus removal technologies is of great significance for maintaining water environmental safety and ecological health.

[0003] Currently, commonly used phosphorus removal technologies mainly include biological methods, chemical precipitation methods, and adsorption methods. Among them, adsorption methods have become a research hotspot due to their simple operation, high efficiency, and moderate cost. Among many adsorption materials, lanthanum-based materials are widely considered to be one of the most promising phosphorus removal agents due to their high affinity for phosphate ions, which can form stable lanthanum phosphate precipitates.

[0004] Existing technologies have disclosed various adsorption composite materials based on lanthanum or other metals. For example, CN118320796A discloses a biodegradable polymer-based composite material, which uses a biodegradable polymer (such as PBAT) as a matrix to construct micro-nano channels and loads phosphorus removal functional components such as iron and lanthanum. This technology aims to achieve the integration of phosphorus removal and slow release of phosphate fertilizer, but its phosphorus removal functional components are mainly loaded through physical blending and phase separation, which may limit the uniformity of dispersion and binding strength, and does not address the fundamental problem of easy agglomeration of nano-active components. CN119258982A discloses a modified carbon fiber-supported lanthanum composite material, which loads lanthanum onto carbon fibers through an impregnation-calcination process, demonstrating good adsorption capacity and resistance to anion interference. However, its preparation process involves high-temperature calcination, resulting in high energy consumption, and the carbon fiber support is not biodegradable. If it cannot be efficiently regenerated after adsorption saturation, there may be secondary disposal problems. CN120094558A discloses a cellulose / chitosan / lanthanum oxide composite material, which synthesizes lanthanum oxide in situ via a hydrothermal method for the simultaneous removal of nitrogen and phosphorus. This material utilizes a natural polymer framework to alleviate some of the aggregation problem, but the hydrothermal process is relatively complex, and its core mechanism still focuses on adsorption. It does not adequately explain the long-term fixation stability of phosphorus (such as resistance to desorption and environmental changes) and the resource utilization pathway of the products after adsorption saturation.

[0005] Based on current technologies, the development of highly efficient lanthanum-based phosphorus fixation materials still faces the following key bottlenecks: First, due to their high surface energy, nanoscale lanthanum-based materials are prone to agglomeration during preparation and use, leading to insufficient exposure of active sites and a significant decrease in specific surface area, thereby weakening phosphorus fixation capacity and reaction rate. Second, most materials rely primarily on surface adsorption, resulting in relatively weak interactions, which are problematic in complex water bodies (especially those containing high concentrations of phosphorus). Phosphate is easily desorbed or competitively adsorbed in the presence of coexisting anions, resulting in decreased phosphorus fixation efficiency and selectivity. Furthermore, some adsorbents have insufficient binding stability with phosphate ions, and are prone to secondary release when the pH of the water fluctuates, making it difficult to achieve long-term stable fixation.

[0006] In summary, there is an urgent need to develop a novel lanthanum-based phosphorus fixation material that can fundamentally inhibit nanoparticle aggregation, construct a stable and irreversible phosphorus fixation mechanism, and achieve high-capacity, high-selectivity, and high-speed phosphorus fixation under complex aquatic conditions, so as to realize the efficient, stable fixation and sustainable recycling of phosphorus. Summary of the Invention

[0007] To address the problems of insufficient active sites, low phosphorus fixation capacity, unstable adsorption, and easy secondary release of absorbed phosphate groups in current lanthanum-based materials, this invention provides a highly efficient and stable phosphorus-fixing lanthanum-based nanocomposite material, its preparation method, and its applications. The lanthanum-based nanocomposite material of this invention uses lysozyme protein fibers as a structural template, utilizing their ultra-high aspect ratio (>10). 3 The confined space formed by the nanometers enables the controllable synthesis of highly dispersed lanthanum oxide nanoparticles with a sub-5nm diameter.

[0008] The first aspect of this invention provides a phosphorus-fixing lanthanum-based nanocomposite material, comprising lysozyme protein fibers as the structural matrix and lanthanum oxide nanoparticles as the active component; wherein the lysozyme protein fibers are interwoven to form confined spaces with a spatial network structure, and the lanthanum oxide nanoparticles are uniformly dispersed within these confined spaces; wherein the diameter of the lanthanum oxide nanoparticles is 1-5 nm, and the aspect ratio of the lysozyme protein fibers is greater than 10. 3 .

[0009] Furthermore, lysozyme protein cellulose is formed by heating a lysozyme protein solution at pH 2.0~3.0 and 80~85℃ for 10~12 hours, causing it to undergo thermal denaturation and self-assembly.

[0010] Furthermore, the lanthanum oxide nanoparticles are generated from lanthanum ion precursors anchored on lysozyme protein fibers through hydrolysis and subsequent transformation under pH 4.0–5.0 conditions.

[0011] Furthermore, the mass ratio between the lysozyme protein fiber and the lanthanum source providing lanthanum ions is 1:1 to 1:3.

[0012] In the above technical solution, the lanthanum-based nanocomposite material uses lysozyme protein fibers as the matrix and lanthanum oxide nanoparticles as the reinforcement, forming a network structure in which lanthanum oxide nanoparticles are uniformly dispersed in the confined space of the lysozyme protein fibers; wherein, the diameter of the lanthanum oxide particles is 1-5 nm, and the aspect ratio of the lysozyme protein fibers is greater than 10. 3 The lanthanum-based nanocomposite material forms a confined space in a spatial network structure through the interlacing of lysozyme protein fibers. The precipitation of lanthanum oxide within the confined space of the lysozyme protein fibers is achieved through the electrostatic attraction and bond-site coordination between the functional groups such as carboxyl, amino, carbonyl, and hydroxyl groups on the lysozyme fibers and lanthanum ions, thereby specifically capturing and fixing lanthanum ions. The functional groups on the lysozyme fibers provide nucleation sites for lanthanum ions. By adjusting the pH value of the subsequent reaction environment, nano-lanthanum oxide particles are precipitated, forming a composite material structure in which nano-lanthanum oxide particles are uniformly distributed within the lysozyme protein fiber network architecture with lysozyme fibers as the matrix.

[0013] Preferably, the lanthanum oxide nanoparticles of the lanthanum-based nanocomposite material are uniformly distributed within the confined space formed by the lysozyme fibers, creating an organic-inorganic hybrid structure with hierarchical channels. This gives the lanthanum-based composite material high specific surface area and high dispersibility, enabling it to effectively treat phosphorus wastewater. The irreversible fixation mechanism is as follows: Phosphorus wastewater contains a large amount of... Lanthanum phosphate is formed by the precipitation reaction of lanthanum oxide surface-active lanthanum ions in lanthanum-based nanocomposites. The reaction equation is as follows: .

[0014] On the other hand, this invention application provides a method for preparing a phosphorus-fixing lanthanum-based nanocomposite material, which includes the following steps: S1. Preparation of lysozyme amyloid fibers with high aspect ratio: Prepare lysozyme protein solution and prepare lysozyme protease fibers with high aspect ratio; S11. Prepare protein solution and adjust the cellulose polymerization reaction environment: Add ultrapure water to dry lysozyme powder to obtain lysozyme protein solution; S12. Adjusting pH and reaction temperature to rearrange and assemble lysozyme protein structure to form lysozyme protein fibers with high aspect ratio: Adjusting the pH of the lysozyme protein solution in step S11 to destroy the natural spherical structure of lysozyme and rearrange it. The rearranged protein molecules undergo directional aggregation through intermolecular interactions such as hydrophobic interactions and hydrogen bonds. Their peptide chain fragments unfold and form a stacked structure rich in β-sheets. Using this as the nucleation starting point, the protein molecules continuously extend along the one-dimensional direction and self-assemble, eventually forming a lysozyme protein fiber network with high aspect ratio.

[0015] S2. Preparation of lanthanum-based nanocomposite materials: Prepare a mixed solution and prepare lanthanum-based lysozyme nanocomposite materials; S21. Prepare a mixed solution: Mix the lysozyme protein cellulose solution prepared in step S12 with La(NO)3·6H2O and stir to obtain a premixed solution; S22, Preparation of lanthanum-based lysozyme nanocomposites by adjusting the pH value of the preparation environment. Or LaOOH precursor: By adjusting the pH of the premixed solution in step S21 to... and generate Alternatively, a LaOOH precursor can be used to obtain a second solution; S23. Adjusting the reaction environment temperature to directionally dehydrate and rearrange the precursor to obtain lanthanum-based lysozyme nanocomposite materials: The precursor, which is anchored in the confined space of the lysozyme fiber, undergoes directional dehydration and structural rearrangement, gradually transforming into crystalline lanthanum oxide to obtain lanthanum-based lysozyme nanocomposite materials.

[0016] Preferably, in step S11, the dry lysozyme powder and ultrapure water are mixed and stirred for 5-10 minutes, and the mass fraction of the lysozyme protein solution is 2-5%.

[0017] Preferably, the specific preparation method of step S12 is as follows: Add concentrated hydrochloric acid (30-35% concentration) dropwise to the lysozyme protein solution prepared in step S11 to adjust the pH value of the premixed protein solution to 2.0-3.0, obtaining a first solution. Heat the first solution in a water bath for 10-12 hours to obtain a lysozyme protein fiber solution with a high aspect ratio. The water bath heating temperature is 80-85℃, and magnetic stirring is maintained throughout the heating process.

[0018] Preferably, the mass ratio of the lysozyme protein cellulose solution and La(NO)3·6H2O in step S21 is 1:1 to 1:3. The stirring process in step S21 involves mixing the high aspect ratio lysozyme protein cellulose solution with La(NO)3·6H2O first using a vortex mixer for 10-12 minutes, and then magnetically stirring for 8-12 hours to obtain a premixed solution.

[0019] Preferably, in step S22, the pH of the premixed solution is adjusted to 4.0-5.0 by adding a 1% (w / w) NaOH solution to the first solution prepared in step S21. The added OH⁻ ions in the reaction system can react with the La⁻ ions anchored on the carboxyl groups and other functional groups of the lysozyme protein cellulose. 3+ Localized, controlled hydrolysis occurs, producing amorphous La(OH)3. The reaction equation is as follows: .

[0020] Preferably, step S23 involves reacting the second solution from step S22 in a shaker for 6-10 hours, causing La(OH)3 to decompose thermally to produce the intermediate LaOOH, ultimately generating crystalline form under warm conditions. The precipitated nano-lanthanum oxide particles are uniformly distributed within the confined space of the lysozyme fiber.

[0021] Preferably, the lanthanum oxide nanoparticles inside the lanthanum-based nanocomposite material have high surface activity. It undergoes coordination exchange with phosphate ions in phosphorus wastewater, forming an internal coordination complex at the interface. Subsequently, through stepwise structural rearrangement and crystallization, it transforms into a thermodynamically stable lanthanum phosphate precipitate. In water bodies with competing anion concentrations of 0–1000 mg / L, the removal rate of phosphate ions is greater than 90%.

[0022] Compared with the prior art, the beneficial effects of this invention application are as follows: 1. This invention provides a novel synthetic approach for lanthanum-based nanocomposites. The composite material prepared using lysozyme protein fibers as a template exhibits a significantly higher phosphorus adsorption capacity (346.99 mg / g) than the comparative material using conventional lactoglobulin as a matrix (179.44 mg / g). This is attributed to the unique two-stage synergistic mechanism of lysozyme: firstly, the carboxyl and amino functional groups in its protein network can specifically anchor... Firstly, it provides uniform nucleation sites at the molecular scale; secondly, lysozyme self-assembles under specific conditions to form a high aspect ratio (>10). 3 The flexible fiber network forms a unique "nano confinement space," effectively regulating the growth kinetics of lanthanum oxide crystals, inhibiting their aggregation, and ultimately ensuring the acquisition of uniform (1-5 nm) and highly dispersed nano-sized lanthanum oxide active components. This synthetic pathway, characterized by a synergistic effect of "functional group anchoring-spatial confinement," is key to achieving high performance.

[0023] 2. The phosphorus-fixing lanthanum-based nanocomposite material of this invention possesses high dispersibility and multi-level pore characteristics, exhibiting a dual mechanism of phosphorus removal and fixation. By enriching phosphate ions in phosphorus-containing wastewater and then performing phosphorus fixation, over 90% of the phosphorus in the wastewater can be removed. The composite interface of positively charged lysozyme protein fibers and lanthanum oxide can efficiently anchor and enrich phosphate ions in the water through electrostatic interaction. Subsequently, the highly dispersed nano-lanthanum oxide provides a large number of active sites, undergoing an in-situ precipitation reaction to generate thermodynamically stable lanthanum phosphate, achieving deep purification of phosphorus. This process is irreversible, thus completely avoiding the risk of secondary release. Furthermore, lanthanum phosphate can be considered a potential phosphate rock. This material, directly or after simple processing, can be used as a raw material for slow-release phosphate fertilizers or industrial phosphate chemicals, thereby successfully transforming pollutants in water into valuable products and realizing a closed-loop recycling from "pollution purification" to "waste value enhancement."

[0024] 3. The phosphorus-fixing lanthanum-based nanocomposite material of this invention can effectively and precisely adsorb phosphate ions in environments influenced by various ions, achieving precise phosphorus fixation, especially when high concentrations of phosphate ions are present in wastewater. , Even with competing ions (competing ion concentration of 0-1000 mg / L), this method can still maintain a phosphorus removal rate of over 90%, demonstrating excellent phosphorus selective adsorption performance. Attached Figure Description

[0025] Figure 1 This is a transmission electron microscope image of the lanthanum-based nanocomposite material of the present invention; Figure 2 The XRD pattern of the lanthanum-based nanocomposite material of the present invention and its phosphorus fixation is shown below. Figure 3 The competing ions of the present invention Adsorption selectivity diagram of phosphorus under the presence of conditions; Figure 4 The competing ions of the present invention Adsorption selectivity diagram of phosphorus under the presence of conditions; Figure 5 The competing ions of the present invention Adsorption selectivity diagram of phosphorus under the presence of conditions; Figure 6 This is a selective adsorption diagram of phosphorus for lanthanum-based nanocomposites of different protein fibers according to the present invention; Figure 7 This is a flowchart illustrating the preparation process of the lanthanum-based nanocomposite material of the present invention. Detailed Implementation

[0026] To fully describe the technical content, structural features, objectives, and effects of this invention, the following detailed description will be provided in conjunction with the accompanying drawings.

[0027] Using the phosphorus-fixing lanthanum-based nanocomposite material of this invention as a structural template, and utilizing its ultra-high aspect ratio (>10) 3 A confined space was constructed to achieve the controllable synthesis of highly dispersed lanthanum oxide nanoparticles with a diameter of 1-5 nm. The lanthanum-based nanocomposite material uses lysozyme protein fibers as the matrix and lanthanum oxide nanoparticles as the reinforcement, forming a network structure in which lanthanum oxide nanoparticles are uniformly dispersed within the confined space of the lysozyme protein fibers; wherein the diameter of the lanthanum oxide particles is 1-5 nm, and the aspect ratio of the lysozyme protein fibers is greater than 10. 3 Lanthanum-based nanocomposites utilize the confined space of a spatial network structure formed by the interlacing of lysozyme protein fibers. The precipitation of lanthanum oxide within this confined space is achieved through the electrostatic attraction and bond-site coordination between the functional groups such as carboxyl, amino, carbonyl, and hydroxyl groups on the lysozyme fibers and lanthanum ions, resulting in the specific capture and fixation of lanthanum ions. The functional groups on the lysozyme fibers provide nucleation sites for lanthanum ions. By adjusting the pH value of the subsequent reaction environment, nano-lanthanum oxide particles are precipitated, forming a composite material structure in which nano-lanthanum oxide particles are uniformly distributed within the lysozyme protein fiber network architecture, with the lysozyme fibers as the matrix.

[0028] like Figure 7 As shown, the specific steps of the preparation method of the phosphorus-fixing lanthanum-based nanocomposite material of this invention are as follows: S1. Preparation of lysozyme amyloid fibers with high aspect ratio: Prepare lysozyme protein solution and prepare lysozyme protease fibers with high aspect ratio.

[0029] S11. Prepare protein solution and adjust the fiber polymerization reaction environment: Add ultrapure water to dry lysozyme powder to dissolve and prepare protein solution with a mass fraction of 2-5%. Stir for 5-10 minutes to obtain premixed protein solution. Add concentrated hydrochloric acid with a concentration of 30-35% to adjust the pH of the protein solution to 2.0-3.0 to obtain lysozyme protein solution.

[0030] In step S11, the mass fraction of the protein solution must not exceed 5%. The main reason is that if the mass fraction of the protein solution is too high, it is easy to generate agglomerates or flocculent proteins during the subsequent heating polymerization process, which will affect the proportion of fibrous proteins with high aspect ratio. Short fibrous proteins are not conducive to the subsequent preparation of lanthanum-based nanocomposites. In addition, the mass fraction of the protein solution must not be less than 2%. The main reason is that if the mass fraction of the protein solution is too low, it is difficult to form long chain structures and the fiber growth is slow.

[0031] Furthermore, adjusting the pH value of the protein solution is a core step in preparing protein fibers with a high aspect ratio. Controlling the pH value between 2.0 and 3.0 enables the protein fibers to nucleate rapidly, forming a large number of fibers and improving production efficiency.

[0032] S12. Adjusting pH and reaction temperature to rearrange the lysozyme protein structure and assemble it into lysozyme protein fibers with a high aspect ratio: Add concentrated hydrochloric acid (30-35%) dropwise to the lysozyme protein solution prepared in step S11 to adjust the pH of the premixed protein solution to 2.0-3.0, obtaining the first solution. Heat the first solution in a water bath for 10-12 hours to obtain a lysozyme protein fiber solution with a high aspect ratio. The water bath heating temperature is 80-85℃, and magnetic stirring is maintained throughout the heating process.

[0033] The main mechanism for the formation of lysozyme protein fibers with a high aspect ratio is as follows: During water bath heating, lysozyme undergoes thermal denaturation in an acidic environment. The first stage occurs at 80-85℃, where the acidic conditions enhance electrostatic repulsion within the lysozyme protein molecules, disrupting the natural spherical structure and transforming it into a loose, dynamic intermediate state. This structure is more conducive to intermolecular interactions and rearrangement. Subsequently, the second stage forms lysozyme protein fibers with a high aspect ratio. In the first stage, these denatured protein molecules undergo directional aggregation through intermolecular interactions such as hydrophobic interactions and hydrogen bonds. Their peptide chain fragments unfold and form a stacked structure rich in β-sheets. Using this as a nucleation starting point, the protein molecules continuously extend along the one-dimensional direction and self-assemble, ultimately forming lysozyme protein fibers with a high aspect ratio. Multiple lysozyme protein fibers with a high aspect ratio intertwine to form a network structure.

[0034] Furthermore, after the reaction in step S12 is completed, the obtained sample is placed between polarizers and illuminated with light. When the observed sample shows a colorful fibrous morphology, it indicates that the lysozyme protein fiber has been successfully prepared.

[0035] S2. Preparation of lanthanum-based nanocomposite materials: Prepare a mixed solution and prepare lanthanum-based lysozyme nanocomposite materials.

[0036] S21. Prepare the mixed solution: Mix the lysozyme protein cellulose solution prepared in step S12 with La(NO)3·6H2O and mix them in a vortex mixer for 10-12 min to obtain a premixed solution. The mass ratio of the lysozyme protein cellulose solution to La(NO)3·6H2O is 1:1 to 1:3. Stir the premixed solution magnetically for 8-12 h to obtain the premixed solution.

[0037] In step S21, lysozyme protein fibers are used to prepare the biological template and functional substrate for lanthanum-based nanocomposites. Lysozyme hydrolyzes and self-assembles in an acidic environment to form fibrous or network gel structures rich in β-sheets. These fibers are rich in active functional groups such as carboxyl and amino groups, which can effectively bind metal ions; while La(NO)3·6H2O can ionize in aqueous solution... It is a small ion with high charge density that readily interacts with the active functional groups such as carboxyl and amino groups of lysozyme protein through strong electrostatic interactions and coordination. Ultimately, lanthanum oxide is generated in the confined space of lysozyme protein fibers, forming a continuous nano-confined network structure. Finally, a lanthanum-based nanocomposite material with nano-lanthanum oxide uniformly loaded in the confined space of protein fibers is obtained.

[0038] Furthermore, a mass ratio of lysozyme protein cellulose solution to La(NO)3·6H2O of 1:1 to 1:3 ensures effective binding with lysozyme protein cellulose. By applying an appropriate loading level to ensure the stability of the resulting continuous nano-confined network structure, vortex oscillations can ensure rapid and uniform mixing. Ions can rapidly diffuse throughout the system, making full contact with protein fibers and avoiding spontaneous precipitation in the bulk phase due to excessively high local concentrations; the shaker can provide a suitable environment for lysozyme, protein fibers, and... Provides gentle, continuous dynamic mixing, promoting The diffusion and adsorption equilibrium of ions into the internal pores and low-accessibility sites of protein fibers.

[0039] S22, Preparation of lanthanum-based lysozyme nanocomposites by adjusting the pH value of the preparation environment. Alternatively, the LaOOH precursor: The pH of the premixed solution is adjusted to 4.0-5.0 by adding a 1% (w / w) NaOH solution dropwise to the first solution prepared in step S21. and generate Alternatively, a LaOOH precursor can be used to obtain a second solution.

[0040] Among them, the reaction system added in step S22 is Ions can bind to functional groups such as carboxyl groups anchored on lysozyme protein filaments. Localized, controlled hydrolysis occurs, producing amorphous La(OH)3. The reaction equation is as follows: .

[0041] S23. Adjusting the reaction environment temperature to directionally dehydrate and rearrange the precursor to obtain lanthanum-based lysozyme nanocomposite materials: The second solution from step S22 is placed in a shaker and reacted for 6-10 hours, causing La(OH)3 to decompose upon heating to produce the intermediate LaOOH, ultimately forming a crystalline form under warm conditions. The precipitated nano-lanthanum oxide particles are uniformly distributed within the confined space of the lysozyme fiber.

[0042] The following describes, in conjunction with embodiments, a method for preparing solidified soil and concrete based on the synergistic activation of red mud-based solid waste: Example 1 Lysozyme powder was dissolved in ultrapure water to prepare a 2% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. Subsequently, the lysozyme protein fiber solution was mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:1. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 12 hours. The pH of the system was then precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 8 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0043] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.5 g / L, wastewater pH 6.0, water temperature 25℃, and initial phosphorus concentration 100 mg / L. Simultaneously, phosphorus was introduced into the water... Coexisting ions (concentration 200 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 95%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0044] Example 2 Lysozyme powder was dissolved in ultrapure water to prepare a 4% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. Subsequently, the lysozyme protein fiber solution was mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:3. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 12 hours. The pH of the system was then precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 9 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0045] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.0 g / L, wastewater pH 8.0, water temperature 25℃, and initial phosphorus concentration 20 mg / L. Simultaneously, phosphorus was introduced into the water... Coexisting ions (concentration 600 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 99%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0046] Example 3 Lysozyme powder was dissolved in ultrapure water to prepare a 3% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. Subsequently, the lysozyme protein fiber solution was mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:1. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 10 hours. The pH of the system was then precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 7 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0047] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 0.5 g / L, wastewater pH 8.0, water temperature 25℃, and initial phosphorus concentration 150 mg / L. Simultaneously, phosphorus was introduced into the water body... Coexisting ions (concentration 300 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 90%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0048] Example 4 Lysozyme powder was dissolved in ultrapure water to prepare a 4% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. The lysozyme protein fiber solution was then mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:2. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 11 hours. Subsequently, the pH of the system was precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for another 10 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0049] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.2 g / L, wastewater pH 7.0, water temperature 25℃, and initial phosphorus concentration 180 mg / L. Simultaneously, phosphorus was introduced into the water... Coexisting ions (concentration 800 mg / L) were used to investigate selectivity. The results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 93%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0050] Example 5 Lysozyme powder was dissolved in ultrapure water to prepare a 5% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. Subsequently, the lysozyme protein fiber solution was mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:2. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 12 hours. The pH of the system was then precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 8 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0051] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.0 g / L, wastewater pH 6.0, water temperature 25℃, and initial phosphorus concentration 200 mg / L. Simultaneously, phosphorus was introduced into the water body... Coexisting ions (concentration 300 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 98%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0052] Example 6 Lysozyme powder was dissolved in ultrapure water to prepare a 2% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. The lysozyme protein fiber solution was then mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:3. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 11 hours. Subsequently, the pH of the system was precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 7 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0053] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 0.5 g / L, wastewater pH 7.0, water temperature 25℃, and initial phosphorus concentration 50 mg / L. Simultaneously, phosphorus was introduced into the water... Coexisting ions (concentration 500 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 98%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0054] Example 7 Lysozyme powder was dissolved in ultrapure water to prepare a 3% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. The lysozyme protein fiber solution was then mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:2. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 10 hours. Subsequently, the pH of the system was precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 8 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0055] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.5 g / L, wastewater pH 6.0, water temperature 25℃, and initial phosphorus concentration 200 mg / L. Simultaneously, phosphorus was introduced into the water body... Coexisting ions (concentration 1000 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 97%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0056] Example 8 Lysozyme powder was dissolved in ultrapure water to prepare a 3% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. The lysozyme protein fiber solution was then mixed with La(NO)₃·6H₂O in a 100mL plastic bottle at a mass ratio of 1:1. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 12 hours. Subsequently, the pH of the system was precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for another 10 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0057] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.0 g / L, wastewater pH 7.0, water temperature 25℃, and initial phosphorus concentration 100 mg / L. Simultaneously, phosphorus was introduced into the water body... Coexisting ions (concentration 600 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 94%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0058] Example 9 Lysozyme powder was dissolved in ultrapure water to prepare a 4% (w / w) protein solution. After the protein was completely dissolved, the pH of the solution was adjusted to approximately 2.0 using concentrated hydrochloric acid. The protein solution was then placed in an 80°C water bath and heated continuously for 10 hours with magnetic stirring to induce thermal denaturation and polymerization of the protein in an acidic environment, forming a fibrous structure with a high aspect ratio. Subsequently, the lysozyme protein fiber solution was mixed with La(NO)3·6H2O in a 100mL plastic bottle at a mass ratio of 1:1. After thorough mixing using a vortex mixer, the mixture was reacted in a shaker for 10 hours. The pH of the system was then precisely adjusted to 4.0 using 1% NaOH solution, and the mixture was further reacted in a shaker for 8 hours. Lanthanum-based lysozyme nanocomposite materials were finally obtained through the above interfacial confined precipitation method.

[0059] The adsorption of the nanocomposite material was evaluated by adding it to phosphorus-containing domestic wastewater. The experimental conditions were controlled as follows: solid-liquid ratio 1.5 g / L, wastewater pH 8.0, water temperature 25℃, and initial phosphorus concentration 200 mg / L. Simultaneously, phosphorus was introduced into the water body... Coexisting ions (concentration 800 mg / L) were used to investigate selectivity. Results showed that the composite material exhibited excellent adsorption selectivity for phosphorus, achieving a fluoride ion removal rate of up to 97%, and demonstrated strong resistance to competing ion interference. After 24 hours of adsorption, phosphorus, confined by the protein fiber template, was in-situ converted to lanthanum phosphate via lanthanum oxide anchoring, thus achieving efficient phosphorus fixation.

[0060] like Figure 1 As shown, the lanthanum oxide nanoparticles in the phosphorus-fixing lanthanum-based nanocomposite material of this invention are uniform in size and highly dispersed within the confined space of the lysozyme protein fibers. The resulting protein fibers have a diameter of less than 5 nm and an aspect ratio of approximately 10. 3 The nanoscale size of lanthanum oxide obtained by confinement is approximately 5-10 nm.

[0061] like Figure 2 As shown, the XRD pattern of the phosphorus-fixing lanthanum-based nanocomposite material of this invention corresponds to the crystal structure of lanthanum oxide, indicating successful loading of lanthanum oxide. After treating phosphorus wastewater, characteristic peaks of lanthanum phosphate can be observed, indicating successful conversion into stable lanthanum phosphate. Furthermore, the peak values ​​of the precipitate generated in the figure did not show significant shifts after XRD tests at 1d, 2d, and 3d, respectively, indicating that its composition is very stable.

[0062] like Figure 3 As shown, the phosphorus-fixing lanthanum-based nanocomposite material of this invention, compared with synthetic lanthanum oxide, commercial lanthanum oxide, and commercial phoslock materials, exhibits superior performance at high Cl concentrations. - Even when competing ions (0–1000 mg / L) coexist, the removal rate of phosphorus ions is still as high as 90% or more, indicating high selectivity for phosphorus.

[0063] Figure 4 As shown, the phosphorus-fixing lanthanum-based nanocomposite material of this invention, compared with synthetic lanthanum oxide, commercial lanthanum oxide, and commercial phoslock materials, exhibits superior performance in high concentrations of NO3. - Even when competing ions (0–1000 mg / L) coexist, the removal rate of phosphorus ions is still as high as 90% or more, indicating high selectivity for phosphorus.

[0064] Figure 5 As shown, the phosphorus-fixing lanthanum-based nanocomposite material of this invention, compared with synthetic lanthanum oxide, commercial lanthanum oxide, and commercial phoslock materials, exhibits superior performance under high SO4 concentrations. 2-Even when competing ions (0–1000 mg / L) coexist, the removal rate of phosphorus ions is still as high as 90% or more, indicating high selectivity for phosphorus.

[0065] Specifically, during contact with phosphorus-containing water, the material can generate stable lanthanum phosphate through an in-situ transformation reaction, achieving efficient and irreversible phosphorus fixation. This technology combines the high phosphorus removal capacity of nano-lanthanum oxide with the stable confinement characteristics of protein fibers, achieving a synergistic effect of deep phosphorus removal and long-term phosphorus fixation, and is suitable for phosphorus pollution control and resource recovery in complex aquatic environments.

[0066] Figure 6 This study investigated the phosphorus adsorption selection of lanthanum-based nanocomposites from different protein fibers. A lactoglobulin lanthanum-based nanocomposite was used as a comparative example, prepared using the same method as in Example 1. Under conditions of an initial phosphorus concentration of 500 ppm (pH approximately 7.0), the lactoglobulin lanthanum-based nanocomposite and the lysozyme protein lanthanum-based nanocomposite of this application (solid-liquid ratio 1 g / L) were added to a solution. After shaking and reacting for 24 h, the concentration in the effluent was measured, and the phosphorus adsorption capacity was calculated.

[0067] As shown in the figure, this application selects lysozyme protein fibers as the structural matrix, which has significant and verifiable performance advantages. For example... Figure 6 As shown, the composite material based on lysozyme exhibits a phosphorus adsorption capacity as high as 346.99 mg / g, representing a performance improvement of over 93% compared to the conventional lactoglobulin-based comparative material (179.44 mg / g). This significant difference stems directly from the unique self-assembly characteristics of lysozyme: under acidic thermal induction, it can form structures with extremely high aspect ratios (>10). 3 The uniform and robust mesh fibers create an excellent nano-confined space. This space effectively isolates and stabilizes the lanthanum ion precursor, ultimately generating small (1-5 nm) and highly dispersed lanthanum oxide nanoparticles. This greatly increases the density of active sites and fundamentally solves the key technical bottlenecks of easy agglomeration of nanoparticles and insufficient exposure of active sites.

[0068] Therefore, the choice of lysozyme as a specific protein in this application is not obvious. It not only achieves a doubling of adsorption capacity, but also ensures that the composite material can still maintain a phosphorus removal rate of >90% in the presence of high concentrations of competing anions (0-1000 mg / L) by constructing a stable "organic-inorganic" hybrid structure, thus possessing high capacity, high selectivity and high stability.

[0069] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A phosphorus-fixing lanthanum-based nanocomposite material, characterized in that, The lysozyme protein fiber is used as a structural matrix, and lanthanum oxide nanoparticles are used as an active component; the lysozyme protein fibers are interlaced to form a limited space with a space net structure, and the lanthanum oxide nanoparticles are uniformly dispersed in the limited space; wherein the diameter of the lanthanum oxide nanoparticles is 1-5 nm, and the length-diameter ratio of the lysozyme protein fiber is greater than 10 3 .

2. The lanthanum-based nanocomposite of claim 1, wherein, The lysozyme protein fiber is formed by heating the lysozyme protein solution at pH 2.0~3.0 and 80~85℃ for 10~12 hours, causing it to undergo thermal denaturation and self-assembly.

3. The lanthanum-based nanocomposite of claim 1, wherein, The lanthanum oxide nanoparticles are generated from lanthanum ion precursors anchored on lysozyme protein fibers through hydrolysis at pH 4.0–5.0 and subsequent transformation.

4. The lanthanum-based nanocomposite of claim 1, wherein, The mass ratio between the lysozyme protein fiber and the lanthanum source providing lanthanum ions is 1:1 to 1:

3.

5. A method for preparing a lanthanum-based nanocomposite material of the type for fixing phosphorus, characterized in that, It includes the following steps: S1. Preparation of lysozyme amyloid fibers with high aspect ratio: Prepare lysozyme protein solution and prepare lysozyme protease fibers with high aspect ratio, with a mass fraction of 2-5%; S11. Prepare protein solution and adjust the fiber polymerization reaction environment: Add ultrapure water to dry lysozyme powder to obtain lysozyme protein solution; S12. Adjusting pH and reaction temperature to rearrange and assemble lysozyme protein structure to form lysozyme protein fibers with high aspect ratio: Adjusting the pH of the lysozyme protein solution in step S11 to destroy the natural spherical structure of lysozyme and rearrange it. The rearranged protein molecules undergo directional aggregation through intermolecular interactions such as hydrophobic interactions and hydrogen bonds. Their peptide chain fragments unfold and form a stacked structure rich in β-sheets. Using this as the nucleation starting point, the protein molecules continue to extend along the one-dimensional direction and self-assemble, eventually forming a lysozyme protein fiber network with high aspect ratio. S2. Preparation of lanthanum-based nanocomposites: Prepare a mixed solution and prepare lanthanum-based lysozyme nanocomposites; S21. Prepare a mixed solution: Mix the lysozyme protein cellulose solution prepared in step S12 with La(NO)3·6H2O and stir to obtain a premixed solution; S22, adjusting the ph value of the preparation environment of the lanthanum-based lysozyme nanocomposite material or LaOOH precursor: by adjusting the ph value of the premixed solution in step S21 with generate or LaOOH precursor, a second solution is obtained; S23. Adjusting the reaction environment temperature to directionally dehydrate and rearrange the precursor to obtain lanthanum-based lysozyme nanocomposite materials: The precursor, which is anchored in the confined space of the lysozyme fiber, undergoes directional dehydration and structural rearrangement, gradually transforming into crystalline lanthanum oxide to obtain lanthanum-based lysozyme nanocomposite materials.

6. The method for preparing phosphorus-fixing lanthanum-based nanocomposite materials according to claim 5, characterized in that, The specific preparation method of step S12 is as follows: add concentrated hydrochloric acid with a concentration of 30-35% to the lysozyme protein solution prepared in step S11 to adjust the pH value of the premixed protein solution to 2.0-3.0 to obtain the first solution; The first solution is heated in a water bath for 10-12 hours to obtain a lysozyme protein fiber solution with a high aspect ratio. The water bath temperature is 80-85℃, and magnetic stirring is maintained throughout the heating process.

7. The method for preparing phosphorus-fixing lanthanum-based nanocomposite materials according to claim 5, characterized in that, The mass ratio of the lysozyme protein cellulose solution and La(NO)3·6H2O in step S21 is 1:1 to 1:

3. The stirring process in step S21 involves mixing the high aspect ratio lysozyme protein cellulose solution with La(NO)3·6H2O first using a vortex mixer for 10-12 minutes, and then magnetically stirring the reaction for 8-12 hours to obtain a premixed solution.

8. The method for preparing phosphorus-fixing lanthanum-based nanocomposite materials according to claim 5, characterized in that, Step S22 involves adding a 1% (w / w) NaOH solution to the first solution prepared in step S21 to adjust the pH of the premixed solution to 4.0-5.

0. The reaction system is then supplemented with... Ions can bind to functional groups such as carboxyl groups anchored on lysozyme protein filaments. Localized, controlled hydrolysis occurs, producing amorphous La(OH)3.

9. The method for preparing phosphorus-fixing lanthanum-based nanocomposite materials according to claim 5, characterized in that, Step S23 involves placing the second solution from step S22 into a shaker and reacting it for 6-10 hours, causing La(OH)3 to decompose thermally to produce the intermediate LaOOH, ultimately forming crystalline form under warm conditions. The precipitated nano-lanthanum oxide particles are uniformly distributed within the confined space of the lysozyme fiber.

10. The application of the phosphorus-fixing lanthanum-based nanocomposite material according to any one of claims 1 to 4 in the purification of phosphorus-containing water, characterized in that, The composite material is added to a solution containing... In phosphorus-containing water bodies with competing anions, when the concentration of the competing anions is in the range of 0~1000 mg / L, the composite material has a phosphate ion removal rate of greater than 90%.

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