A lanthanum modified fluorite bimetallic composite phosphorus removal agent, a preparation method and application thereof
By preparing a lanthanum-modified fluorite bimetallic composite phosphorus removal agent, and utilizing its abundant adsorption sites and the affinity of lanthanum, the problem of low adsorption efficiency of existing lanthanum-based adsorbents was solved, achieving rapid and efficient phosphorus removal from water.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA UNIV OF GEOSCIENCES (WUHAN)
- Filing Date
- 2024-05-11
- Publication Date
- 2026-04-17
AI Technical Summary
Existing lanthanum-based adsorbents have an adsorption equilibrium time range of 2-12 hours, resulting in low adsorption efficiency and difficulty in rapidly and effectively reducing phosphorus concentration in water.
A lanthanum-modified fluorite bimetallic composite phosphorus remover was prepared by calcining fluorite ore with dicyandiamide, reacting it with pyrrole and ammonium persulfate to form a hydrogel, and then combining it with a lanthanum source. This process yielded a lanthanum-modified fluorite bimetallic composite phosphorus remover with abundant adsorption sites. The three-dimensional ion channel characteristics of the polypyrrole hydrogel and the affinity of lanthanum were utilized to rapidly adsorb phosphate.
It reaches adsorption equilibrium within 10 minutes, effectively removing phosphates from wastewater, with total phosphorus concentration meeting national discharge standards, achieving rapid and efficient phosphorus removal.
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Figure CN118384847B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of adsorbent technology, and in particular to a lanthanum-modified fluorite bimetallic composite phosphorus removal agent, its preparation method, and its application. Background Technology
[0002] When the total phosphorus concentration in water exceeds 0.02 mg / L, it can induce eutrophication, disrupt the ecological balance of the water body, and affect water quality. Therefore, controlling eutrophication requires reducing the phosphorus concentration in the water. Methods for phosphorus removal from water bodies mainly include chemical precipitation, biological methods, ion exchange, membrane separation, crystallization, electrolysis, and adsorption. Among these, adsorption has attracted attention due to its advantages such as controllability, adaptability, and ease of operation.
[0003] Rare earth metal La (La) possesses strong phosphorus-binding capacity and good water stability, making it one of the most widely used materials for phosphorus removal in water. Therefore, in recent years, an increasing number of researchers have studied and explored novel lanthanum-modified adsorbent materials. However, the adsorption equilibrium time of most lanthanum-based adsorbents ranges from approximately 2 to 12 hours, resulting in low adsorption efficiency. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a lanthanum-modified fluorite bimetallic composite phosphorus removal agent, its preparation method, and its application.
[0005] The present invention discloses a method for preparing a lanthanum-modified fluorite bimetallic composite phosphorus removal agent, comprising the following steps:
[0006] S1. Fluorite ore and dicyandiamide are mixed, ground, and calcined to obtain the calcined product;
[0007] S2, Solution A: Pyrrole is added to deionized water, along with sodium dodecyl sulfate and the calcined product; Solution B: Ammonium persulfate is added to deionized water; Solution B is added to Solution A, and the mixture is allowed to stand to obtain fluorite hydrogel;
[0008] S3. Citric acid was dissolved in ethanol, lanthanum source was added, and the prepared fluorite hydrogel was added. The mixture was stirred and soaked, and the product was washed, dried, ground, and calcined to obtain lanthanum-modified fluorite bimetallic composite phosphorus removal agent.
[0009] Furthermore, in step S1, the mass ratio of fluorite ore to dicyandiamide is 1 to 3:5.
[0010] Furthermore, the mass ratio of citric acid to fluorite ore is 2-6:1-3.
[0011] Furthermore, the molar mass ratio of the lanthanum source to fluorite ore is 0.0005–0.002 M: 0.05–0.15 g.
[0012] Furthermore, the lanthanum source is lanthanum acetylacetonate.
[0013] Furthermore, the calcination temperature in step S1 is 550°C.
[0014] Furthermore, in step S3, the stirring time is 3 to 9 hours.
[0015] Furthermore, in step S3, the calcination temperature is 350–450°C.
[0016] Furthermore, in step S3, the product is washed with ethanol and then dried in an oven.
[0017] A lanthanum-modified fluorite bimetallic composite phosphorus remover prepared by the method described above.
[0018] Application of a lanthanum-modified fluorite bimetallic composite phosphorus removal agent as described above in wastewater phosphorus removal.
[0019] Fluorite has a cubic crystal system with a face-centered cubic lattice, which allows it to be well doped with rare earth ions; meanwhile, Ca... 2+ The ionic radius of La 3+ Since the ionic radii are similar, lanthanum was chosen to modify fluorite. La and Ca have a strong affinity for phosphate groups in water, and the Ca-La bimetallic composite adsorbent has abundant adsorption sites, enabling it to rapidly adsorb phosphate groups in water.
[0020] This invention utilizes the abundant three-dimensional ion channel characteristics of polypyrrole hydrogel, promotes the adsorption of lanthanum source by the hydrogel with citric acid, and regulates the enrichment mode of lanthanum on the fluorite surface during the preparation of lanthanum-modified fluorite bimetallic composite phosphorus removal agent. This results in the preparation of a highly efficient and rapid lanthanum-modified fluorite bimetallic composite phosphorus removal agent for wastewater phosphorus removal. It reaches adsorption equilibrium within 10 minutes, exhibits selectivity for phosphate adsorption, and can remove most phosphorus-containing substances from actual wastewater, ensuring that the total phosphorus concentration in the wastewater meets the national emission standard (0.5 mg P / L, GB 8978-2002). Attached Figure Description
[0021] Figure 1a , Figure 1b Transmission electron microscopy of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention;
[0022] Figure 1b-1 The EDS energy dispersive spectroscopy (EDS) diagram of Ca element distribution of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention;
[0023] Figure 1b-2 The EDS energy spectrum of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention is shown as the elemental distribution of F.
[0024] Figure 1b-3 The EDS energy spectrum of C element distribution of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention;
[0025] Figure 1b-4 The EDS energy dispersive spectroscopy (EDS) spectrum of nitrogen element distribution of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention is shown below.
[0026] Figure 1b-5 The EDS energy dispersive spectroscopy (EDS) diagram of the O element distribution of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention.
[0027] Figure 1b-6 The EDS energy distribution diagram of La element in the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention;
[0028] Figure 2 The adsorption kinetics of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention;
[0029] Figure 3 This is a SEM image of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention. Detailed Implementation
[0030] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0031] Example 1:
[0032] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0033] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0034] The TEM and EDS analysis results of this case are shown in Figure 1. There are certain particulate materials on the surface of the lanthanum-modified fluorite bimetallic composite phosphorus removal agent, and lanthanum and calcium are uniformly dispersed in the adsorbent.
[0035] Figure 3 This is a SEM image of the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 of this invention. Figure 3 It can be seen that the porous particulate matter attached to the surface of the adsorbent is beneficial to exposing more active adsorption sites, increasing the adsorption area, and accelerating the adsorption rate.
[0036] Comparative Example 1:
[0037] Step (1): 0.25g of dicyandiamide was calcined at 550℃ in air for 2h at a heating rate of 5℃ / min to obtain the calcined product; Solution A: 0.15M pyrrole was added to 10ml of deionized water, along with 0.29g of sodium dodecyl sulfate and the ground calcined product, for later use; Solution B: 0.75g of ammonium persulfate was added to 10ml of deionized water, for later use. Solution B was added to Solution A and allowed to stand for 1h to obtain fluorite hydrogel.
[0038] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0039] Example 2:
[0040] Step (1): Mix and grind 0.1g of fluorite ore with 0.5g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0041] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0042] Example 3:
[0043] Step (1): Mix and grind 0.15g of fluorite ore with 0.75g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0044] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0045] Example 4:
[0046] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0047] Step (2): Dissolve 0.1g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0048] Example 5:
[0049] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0050] Step (2): Dissolve 0.3g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0051] Example 6:
[0052] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0053] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.2181g (0.0005M) lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0054] Example 7:
[0055] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0056] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 6h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0057] Example 8:
[0058] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0059] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 9h, then filter. Wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0060] Example 9:
[0061] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0062] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 350℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0063] Example 10:
[0064] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0065] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.4362g of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 450℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0066] Example 11:
[0067] Step (1): Mix and grind 0.05g of fluorite ore with 0.25g of dicyandiamide, and calcine at 550℃ in air for 2h with a heating rate of 5℃ / min to obtain the calcined product; Solution A: Add 0.15M pyrrole to 10ml of deionized water, and add 0.29g of sodium dodecyl sulfate, along with the ground calcined product, for later use; Solution B: Add 0.75g of ammonium persulfate to 10ml of deionized water for later use. Add Solution B to Solution A, let stand for 1h, and obtain fluorite hydrogel.
[0068] Step (2): Dissolve 0.2g of citric acid in 40ml of ethanol, and add 0.8724g (0.002M) of lanthanum acetylacetone. Add the fluorite hydrogel prepared in step (1), stir and soak for 3h, filter, wash the filter residue with ethanol, dry in an oven at 60℃, grind, and calcine at 400℃ in air for 2h at a heating rate of 5℃ / min to obtain lanthanum-modified fluorite bimetallic composite dephosphorizing agent.
[0069] test:
[0070] Taking the lanthanum-modified fluorite bimetallic composite phosphorus remover prepared in Example 1 as an example, the kinetics of phosphate adsorption were studied. The experimental conditions were: lanthanum-modified fluorite bimetallic composite phosphorus remover dosage was 0.4 g / L; initial phosphorus concentration was 25 mg / L; and adsorption times were 5, 10, 15, 20, 25, 30, 40, 50, and 60 min. Specific results are as follows: Figure 2 As shown, the lanthanum-modified fluorite bimetallic composite phosphorus remover exhibits extremely high adsorption efficiency, conforming to the quasi-first-order kinetic model. Adsorption experiments were conducted under the conditions of 0.4 g / L lanthanum-modified fluorite bimetallic composite phosphorus remover, an initial phosphorus concentration of 25 mg / L, and an adsorption time of 10 min. The adsorption capacity of the adsorbents prepared in each example is shown in Table 1.
[0071] Table 1. Adsorption capacity of adsorbents prepared in each example
[0072]
[0073]
[0074] For any points not covered above, existing technologies shall apply.
[0075] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a lanthanum-modified fluorite bimetallic composite phosphorus removal agent, characterized in that: Includes the following steps: S1. Fluorite ore and dicyandiamide are mixed, ground, and calcined to obtain the calcined product; S2, Solution A: Pyrrole is added to deionized water, along with sodium dodecyl sulfate and the calcined product; Solution B: Ammonium persulfate is added to deionized water; Solution B is added to Solution A, and the mixture is allowed to stand to obtain fluorite hydrogel; S3. Citric acid was dissolved in ethanol, lanthanum source was added, and the prepared fluorite hydrogel was added. The mixture was stirred and soaked, and the product was washed, dried, ground, and calcined to obtain lanthanum-modified fluorite bimetallic composite phosphorus removal agent.
2. The preparation method according to claim 1, characterized in that: In step S1, the mass ratio of fluorite ore to dicyandiamide is 1~3:
5.
3. The preparation method according to claim 1, characterized in that: The mass ratio of citric acid to fluorite ore is 2~6:1~3.
4. The preparation method according to claim 1, characterized in that: The lanthanum source is lanthanum acetylacetone.
5. The preparation method according to claim 1, characterized in that: The calcination temperature in step S1 is 550℃.
6. The preparation method according to claim 1, characterized in that: In step S3, the stirring time is 3 to 9 hours.
7. The preparation method according to claim 1, characterized in that: In step S3, the calcination temperature is 350~450℃.
8. The preparation method according to claim 1, characterized in that: In step S3, the product is washed with ethanol and then dried in an oven.
9. A lanthanum-modified fluorite bimetallic composite phosphorus remover prepared by the preparation method according to any one of claims 1-8.
10. The application of the lanthanum-modified fluorite bimetallic composite phosphorus removal agent as described in claim 9 in wastewater phosphorus removal.
Citation Information
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