A rare earth modified montmorillonite composite adsorption material, a preparation method and application thereof
Rare earth-modified montmorillonite composite adsorbent material was prepared by solution combustion, which solved the problems of insufficient adsorption capacity and slow kinetics of traditional adsorbent materials at low concentrations of phosphorus. It achieved efficient and rapid phosphate adsorption and is suitable for treating phosphorus pollution in complex water bodies.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA UNIV OF GEOSCIENCES (WUHAN)
- Filing Date
- 2026-03-05
- Publication Date
- 2026-06-05
AI Technical Summary
Traditional adsorbent materials have insufficient adsorption capacity and selectivity at low concentrations of phosphorus, slow adsorption kinetics, and the active components are prone to aggregation and loss, resulting in poor stability.
Rare earth modified montmorillonite composite adsorbent material was synthesized by solution combustion method. Lanthanum nitrate or cerium nitrate was uniformly dispersed with montmorillonite and glycine in deionized water, and then evaporated and burned to form lanthanum/montmorillonite composite material. Lanthanum nitrate oxide was used as active component and fixed in gel network to achieve uniform mixing and high-temperature self-propagating reaction, thus preparing porous aggregates with a thin sheet-like structure on the surface.
It achieves efficient and rapid phosphate adsorption, reaching adsorption equilibrium within 5 minutes, maintaining high adsorption capacity over a wide pH range, and exhibiting stable performance, especially under neutral to alkaline conditions. It can effectively remove phosphorus from actual wastewater, meeting national discharge standards.
Smart Images
Figure CN122141606A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of adsorption materials technology, and in particular to a rare earth modified montmorillonite composite adsorption material, its preparation method, and its application. Background Technology
[0002] Currently, methods for phosphorus recovery and removal from water bodies mainly include biological methods, chemical precipitation, crystallization, capacitive deionization, natural biological methods, and adsorption. Among these methods, adsorption has attracted much attention due to its simple operation, relatively low cost, and high efficiency. However, traditional adsorption materials still face a series of key technical shortcomings in practical applications, such as: 1) insufficient adsorption capacity and selectivity for low-concentration phosphorus; 2) slow adsorption kinetics, resulting in lower treatment efficiency; and 3) high-performance active components (such as nano-metal oxides) are prone to aggregation and loss, leading to poor stability. These shortcomings restrict the further application of adsorption technology. Montmorillonite, as a natural layered silicate clay mineral, is an ideal carrier material. Its main advantages lie in its unique layered structure, which provides a huge specific surface area and abundant nanoscale pores. The functional groups such as hydroxyl groups on its surface can not only directly participate in adsorption but also stably bind with active components through ion exchange. Montmorillonite itself is widely available, inexpensive, and non-toxic, exhibiting good environmental compatibility and economic efficiency. Lanthanum (cerium) nitrate oxide, as a type of lanthanum (cerium) compound, possesses properties intermediate between lanthanum (cerium) oxide and lanthanum (cerium) nitrate. It exhibits extremely strong specific binding ability to phosphate ions and can achieve rapid adsorption with high capacity and high selectivity through inner-layer complexation and other mechanisms, making it an ideal active component for overcoming the bottleneck of "adsorption performance." Solution combustion can effectively synthesize complex metal compounds. This invention patent utilizes this method to synthesize lanthanum nitrate oxide, a lanthanum active material. Using montmorillonite as a support effectively loads and highly disperses active components such as lanthanum (cerium) nitrate oxide, preventing aggregation and thus exposing more active sites, improving the stability of the active components in complex environments. Summary of the Invention
[0003] The purpose of this invention is to address the shortcomings of the prior art by proposing a rare earth-modified montmorillonite composite adsorbent material with good stability, large adsorption capacity, and fast adsorption speed, as well as its preparation method and application.
[0004] The first objective of this invention is to provide a method for preparing a rare earth modified montmorillonite composite adsorbent material, wherein lanthanum nitrate or cerium nitrate, montmorillonite, and glycine are uniformly dispersed in deionized water to obtain a mixed solution, and the mixed solution is evaporated and burned to obtain montmorillonite loaded with LaONO3 or CeONO3, which is the rare earth modified montmorillonite composite adsorbent material.
[0005] Furthermore, the molar mass ratio of lanthanum or cerium ions to montmorillonite is 0.005 mol: 0.03-0.2 g.
[0006] Furthermore, the concentration of lanthanum or cerium ions in the mixture is 0.08-0.15 mol / L.
[0007] Furthermore, the concentration of lanthanum or cerium ions in the mixture is 0.1 mol / L.
[0008] Furthermore, the molar ratio of glycine to lanthanum nitrate or cerium nitrate is 0.6.
[0009] Furthermore, the heating temperature for evaporative combustion is 380-450℃.
[0010] Furthermore, the heating temperature for evaporative combustion is 400°C.
[0011] The second objective of this invention is to provide a rare earth-modified montmorillonite composite adsorbent prepared using the above-described preparation method.
[0012] A third objective of this invention is to provide an application of the rare earth-modified montmorillonite composite adsorbent material as described above in the adsorption of phosphate in wastewater.
[0013] Furthermore, the pH of the wastewater is 4-10.
[0014] This invention proposes a method for synthesizing a rare-earth modified montmorillonite composite adsorbent using a solution combustion method, achieving efficient and rapid preparation of the rare-earth modified montmorillonite composite adsorbent. Lanthanum nitrate (cerium) serves as both the lanthanum source (cerium source) and the oxidant, glycine as the fuel, and montmorillonite as the carrier. By stirring, the montmorillonite carrier, fuel, and oxidant are mixed uniformly, and lanthanum metal ions are "fixed" in the gel network formed by the fuel and oxidant, thereby achieving uniform mixing at the atomic scale and good dispersion of the lanthanum component. At high temperature, the solution evaporates and burns, and the system undergoes a self-propagating redox reaction, instantly completing the synthesis of the lanthanum / montmorillonite composite material. This reduces interference from prolonged drying and high-temperature calcination, ensuring the synthesis of lanthanum / cerium nitrate oxidized, while also improving preparation efficiency and reducing energy consumption.
[0015] The rare earth modified montmorillonite composite adsorbent material prepared by this invention has a surface composed of irregularly stacked and interwoven sheet-like basic unit structures, forming a loose, open three-dimensional porous aggregate.
[0016] The rare earth modified montmorillonite composite adsorbent prepared by this invention exhibits excellent selective adsorption capacity and extremely high adsorption efficiency for phosphate, reaching adsorption equilibrium within 5 minutes, which is much faster than traditional adsorbents. It can still maintain a high phosphorus removal rate in water bodies where multiple competing anions coexist, and has good adsorption capacity in a wide pH range of 4-10, especially under neutral to alkaline conditions where its performance is more stable.
[0017] It also has a good effect on treating phosphorus-containing substances in actual secondary sedimentation tank effluent. It can remove most of the phosphorus-containing substances in actual sewage, so that the total phosphorus concentration in sewage meets the national discharge standard (0.5 mg P / L, GB 8978-2002). Attached Figure Description
[0018] Figure 1 The image shows the scanning electron microscope (SEM) image of the rare earth-modified montmorillonite composite adsorbent material prepared in Example 1 of this invention. Figure 2 The XRD patterns of the rare earth-modified montmorillonite composite adsorbent materials prepared in Example 1 and Comparative Example 1 of this invention are shown below. Figure 3 The adsorption kinetics of the rare earth modified montmorillonite composite adsorbent materials prepared in Examples 1 and 2 of this invention are shown below. Figure 4 The adsorption performance of the rare earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention on phosphate under the presence of competing ions; Figure 5 The adsorption performance of the composite adsorbent material prepared in Comparative Example 1 of this invention on phosphate under the presence of competing ions; Figure 6 The adsorption performance of rare earth modified montmorillonite composite adsorbent materials prepared in Examples 1 and 2 of this invention on phosphate under different pH conditions; Figure 7 The adsorption performance of the rare earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention on phosphate under actual wastewater (effluent from a secondary sedimentation tank). Figure 8 The XPS high-resolution O 1s spectra of the rare earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention before and after adsorption of phosphate are shown. Detailed Implementation
[0019] 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.
[0020] Example 1 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0021] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. Finally, rare earth lanthanum modified montmorillonite composite adsorbent material was obtained.
[0022] Example 2 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.1 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0023] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. Finally, rare earth lanthanum modified montmorillonite composite adsorbent material was obtained.
[0024] Example 3 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.03 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0025] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. Finally, rare earth lanthanum modified montmorillonite composite adsorbent material was obtained.
[0026] Example 4 (1) Dissolve cerium nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to cerium nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0027] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. Finally, rare earth cerium-modified montmorillonite composite adsorbent material was obtained.
[0028] Comparative Example 1 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate, and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0029] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. The adsorbent material was finally obtained.
[0030] Comparative Example 2 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Add glycine at a molar ratio of 0.8 to lanthanum nitrate nonahydrate, and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0031] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. The adsorbent material was finally obtained.
[0032] Comparative Example 3 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Add glycine at a molar ratio of 1 to lanthanum nitrate nonahydrate, and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0033] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. The adsorbent material was finally obtained.
[0034] Comparative Example 4 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Add glycine at a molar ratio of 0.2 to lanthanum nitrate nonahydrate, and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0035] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. The adsorbent material was finally obtained.
[0036] Comparative Example 5 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.2 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Add glycine at a molar ratio of 0.4 to lanthanum nitrate nonahydrate, and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0037] (2) Transfer the above homogenized solution to an evaporating dish and place it on an electric furnace at 400°C for evaporation and combustion treatment. Final adsorbent material.
[0038] Comparative Example 6 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.25 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0039] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. The adsorbent material was finally obtained.
[0040] Comparative Example 7 (1) Dissolve lanthanum nitrate nonahydrate in 50 mL of deionized water to prepare a solution with a total metal ion concentration of 0.1 mol / L. Add 0.3 g of montmorillonite to the solution and sonicate for 10 minutes to ensure complete dispersion. Then add glycine at a molar ratio of 0.6 to lanthanum nitrate nonahydrate and stir magnetically for 30 minutes to obtain a homogeneous mixed solution.
[0041] (2) The homogenized solution was transferred to an evaporating dish and placed on an electric furnace at 400°C for evaporation and combustion treatment. Finally, rare earth lanthanum modified montmorillonite composite adsorbent material was obtained.
[0042] Taking the adsorbent materials prepared in Examples 1-4 and Comparative Examples 1-7 as examples, the phosphate content before and after adsorption was measured and the adsorption capacity was calculated in 50 ml of a 25 mg / L phosphorus-containing solution after shaking for 30 min. The specific results are shown in Table 1. Data from Comparative Examples 1-5 show that the highest phosphorus removal capacity was achieved when the glycine to nitrate ratio was 0.6. Data from Comparative Examples 6 and 7 show that excessive montmorillonite addition reduces the phosphorus removal capacity of the composite material. Data from Examples 1-5 show that the highest phosphorus removal capacity was achieved when the montmorillonite addition was 0.2 g.
[0043] Table 1
[0044] Taking the rare earth-modified montmorillonite composite adsorbents prepared in Examples 1, 2, and 3 as examples, the kinetics of phosphate adsorption were studied. The experimental conditions were: the amount of rare earth lanthanum-modified montmorillonite composite adsorbent was 0.2 g / L; the initial phosphorus concentration was 50 mg / L; and the adsorption times were 1, 2, 4, 8, 10, 12, 18, 24, and 30 min, respectively. Specific results are as follows: Figure 3 As shown, the rare earth lanthanum modified montmorillonite composite adsorbent exhibits extremely high adsorption efficiency, reaching adsorption equilibrium within 5 minutes.
[0045] Taking the rare earth lanthanum-modified montmorillonite composite adsorbents prepared in Examples 1, 2, and 3 as examples, the effect of competing ions on their adsorption performance was studied. The experimental conditions were: the amount of rare earth lanthanum-modified montmorillonite composite adsorbent was 0.2 g / L; the initial phosphorus concentration was 50 mg / L; the adsorption time was 30 min; and the competing ions included Cl... SO4 2 CO3 2 HCO3 NO3 Humic acid, with competing ion concentrations of 10 mg / L, 25 mg / L, and 50 mg / L, respectively. Specific results are as follows... Figure 4 , Figure 5 , Figure 6 As shown, the adsorption capacity of the rare earth lanthanum modified montmorillonite composite adsorbent for phosphate remained at a certain level without significant decrease or increase, indicating that the composite material has high selectivity for phosphate.
[0046] Taking the rare earth lanthanum-modified montmorillonite composite adsorbents prepared in Examples 1 and 2 as examples, the effect of pH on its adsorption performance was studied. The experimental conditions were: 0.2 g / L of rare earth lanthanum-modified montmorillonite composite adsorbent; initial phosphorus concentration of 50 mg / L; adsorption time of 30 min; and pH values of 2, 4, 6, 8, 10, and 12. Specific results are as follows: Figure 7 As shown, the rare earth lanthanum modified montmorillonite composite adsorbent material has a high adsorption capacity for phosphate in the pH range of 4-10, and the composite material has high stability.
[0047] Figure 1 The image shown is a scanning electron microscope (SEM) image of the composite adsorbent prepared in Example 1 of this invention, demonstrating the microstructure of the rare-earth lanthanum-modified montmorillonite composite adsorbent. After solution combustion synthesis, the material forms a loose, open three-dimensional porous aggregate structure, providing abundant channels and active sites for the diffusion and adsorption of phosphate ions, thus demonstrating the advantages of this invention in material structure design.
[0048] Figure 2 The XRD patterns of the rare earth lanthanum-modified montmorillonite composite adsorbent materials prepared in Example 1 and Comparative Example 1 of this invention confirm that the composite material is a lanthanum / montmorillonite composite material with lanthanum nitrate oxide as the core.
[0049] Figure 3 The adsorption kinetics of the rare earth lanthanum modified montmorillonite composite adsorbent materials prepared in Examples 1 and 2 of this invention are shown. All samples reached adsorption equilibrium in a very short time (e.g., within 5 minutes), demonstrating that the material of this invention has the significant advantage of rapid adsorption kinetics.
[0050] Figure 4 The adsorption performance of the rare earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention on phosphate under the presence of competing ions; Figure 5 This invention demonstrates the adsorption performance of the composite adsorbent material prepared in Comparative Example 1 on phosphate under the presence of competing ions; from Figure 4 and Figure 5 The comparison shows that, even under the interference of high concentrations of competing ions, the adsorption performance of the composite material prepared in Example 1 remains stable for phosphate, without a significant decrease. This strongly demonstrates that the adsorbent provided by this invention has excellent selective adsorption capacity for phosphate, giving it great application potential in treating complex wastewater.
[0051] Figure 6 The rare earth modified montmorillonite composite adsorbent materials prepared in Examples 1 and 2 of this invention have good adsorption capacity in a wide pH range of 4-10.
[0052] Figure 7 This invention demonstrates the adsorption performance of the rare-earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention on phosphates under actual wastewater (secondary sedimentation tank effluent) conditions. The material effectively removes phosphates from the secondary sedimentation tank effluent, ensuring that the total phosphorus concentration in the wastewater meets the national emission standard (0.5 mg P / L, GB 8978-2002). Figure 8 The XPS high-resolution O 1s spectra of the rare-earth modified montmorillonite composite adsorbent material prepared in Example 1 of this invention before and after phosphate adsorption are shown. The adsorption process involved a surface chemical reaction dominated by anion exchange. The nitrate ligand (-NO3) in the material... - The hydroxyl groups (M-OH) on the material surface are completely replaced, and the area of the hydroxyl groups (M-OH) on the material surface becomes relatively smaller, which also participate in the reaction as coordination sites.
[0053] For any points not covered above, existing technologies shall apply.
[0054] 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 rare earth-modified montmorillonite composite adsorbent material, characterized in that, Lanthanum nitrate or cerium nitrate, montmorillonite, and glycine are uniformly dispersed in deionized water to obtain a mixed solution. The mixed solution is then evaporated and burned to obtain montmorillonite loaded with LaONO3 or CeONO3, which is the rare earth modified montmorillonite composite adsorbent material.
2. The preparation method according to claim 1, characterized in that, The molar mass ratio of lanthanum or cerium ions to montmorillonite is 0.005 mol: 0.03-0.2 g.
3. The preparation method according to claim 1, characterized in that, The concentration of lanthanum or cerium ions in the mixture is 0.08-0.15 mol / L.
4. The preparation method according to claim 1, characterized in that, The concentration of lanthanum or cerium ions in the mixture is 0.1 mol / L.
5. The preparation method according to claim 1, characterized in that, The molar ratio of glycine to lanthanum nitrate or cerium nitrate is 0.
6.
6. The preparation method according to claim 1, characterized in that, The heating temperature for evaporative combustion is 380-450℃.
7. The preparation method according to claim 1, characterized in that, The heating temperature for evaporative combustion is 400℃.
8. A rare earth modified montmorillonite composite adsorbent material prepared by the preparation method according to any one of claims 1-7.
9. The application of the rare earth modified montmorillonite composite adsorbent material as described in claim 8 in the adsorption of phosphate in wastewater.
10. The application as described in claim 9, characterized in that, The pH of the wastewater is 4-10.