A functional magnesium oxide composite material and its preparation method
By constructing a three-dimensional porous cobalt-based MOF framework on the surface of magnesite powder and introducing specific functional groups, the problem of poor adsorption of magnesite was solved, and efficient removal of heavy metal ions and organic pollutants was achieved, making it suitable for wastewater treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUANGGANG NORMAL UNIV
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-26
AI Technical Summary
Existing applications of magnesite in functional materials suffer from poor adsorption and limited functionality, making it difficult to effectively treat multi-component pollutants in complex water bodies.
A three-dimensional porous cobalt-based MOF framework was grown in situ on the surface of magnesite powder via hydrothermal reaction, and nitrogen-containing heterocyclic functional groups were introduced. Subsequently, thiol and phosphate groups were introduced on the material surface to construct an organic-inorganic hybrid cross-linked network, forming a functional magnesite composite material.
It significantly improves the specific surface area and active sites of the material, achieving broad-spectrum and efficient removal of heavy metal ions and organic pollutants. It has the economic advantages of high stability and low cost, and is suitable for wastewater treatment.
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Abstract
Description
Technical Field
[0002] This invention relates to the field of wastewater treatment technology, specifically to a functional magnesium oxide composite material and its preparation method. Background Technology
[0003] Magnesite is an important magnesium resource, primarily composed of magnesium carbonate (MgCO3) with minor impurities such as SiO2, CaO, Al2O3, and Fe2O3. Depending on the impurity composition, it can form varieties such as siliceous, calcareous, aluminous, or ferruginous magnesite. This mineral often occurs in association with or alongside dolomite, calcite, talc, serpentine, chlorite, and quartz, and is characterized by abundant reserves, low mining costs, and environmental friendliness. However, magnesite faces two main challenges in practical applications: firstly, approximately 50% of the raw material is produced as tailings during mining, becoming industrial solid waste; secondly, natural magnesite suffers from low surface activity and insufficient chemical stability, which severely restricts its application in functional materials. Therefore, improving the performance of magnesite through modification techniques has become an important research topic in materials science.
[0004] In recent years, magnesite and its modified materials have attracted widespread attention in the field of wastewater treatment. Studies have shown that magnesite has good adsorption capacity for heavy metal ions, organic pollutants, and phosphates, mainly due to its abundant active sites and ion exchange performance. Furthermore, magnesite-based composite materials can be chemically modified to introduce specific functional groups, further enhancing their selectivity and adsorption capacity. For example, by loading metal oxides or organic functional molecules, highly efficient removal of specific pollutants can be achieved, showing broad application prospects in environmental remediation.
[0005] Chinese patent document CN118719012A discloses a COF@magnesia hydrophoretic composite material, its preparation method, and its application. The preparation method includes the following steps: First, a diisocyanate-based organic compound is used as a modifier to chemically react with magnesium hydrophoretic powder to obtain modified magnesium hydrophoretic powder particles. Second, tris(4-aminophenyl)amine and 2,5-dihydroxyterephthalaldehyde are used as reactants to obtain a covalent organic framework (COF) material. Finally, using the modified magnesium hydrophoretic powder particles as the core and the COF as the shell, a COF@magnesia hydrophoretic composite material is prepared. The COF@magnesia hydrophoretic composite material synthesized in this invention has a simple preparation process, high stability, and good selectivity, and can be used for the adsorption treatment of lead ions in water. This patent mainly targets the adsorption of lead ions in water, and its function is relatively singular. It is not suitable for other heavy metal ions (such as Cu) commonly found in complex water bodies such as dyeing and printing wastewater. 2+ Fe 2+ Cd 2+It is difficult to remove multiple pollutants simultaneously, including organic pollutants such as high COD and dye color. Summary of the Invention
[0006] The main objective of this invention is to propose a method for preparing functional magnesite composite materials, aiming to solve the problems of poor adsorption and limited functionality of existing magnesite materials, and to provide a method for preparing broad-spectrum, efficient and stable functional magnesite composite materials.
[0007] In a first aspect, to achieve the above objectives, the present invention proposes a method for preparing a functional magnesium oxide composite material, comprising the following steps: S1. Add cobalt salt, 4,5-imidazolium dicarboxylic acid and 4,4-bipyridine to water, adjust the pH to 8-9, add magnesite powder to form a suspension, and carry out a hydrothermal reaction to obtain pretreated magnesite powder. S2. Disperse the pretreated magnesite powder in an aqueous ethanol solution, add 3-mercaptopropyltrimethoxysilane and stir to react to obtain mercapto-modified magnesite powder; S3. Thiolized magnesite powder and triglycidyl phosphate are added to acetone and heated with triethylamine as a catalyst to obtain the functional magnesite composite material.
[0008] Based on the above technical solutions, preferably, the cobalt salt in step S1 is at least one of cobalt chloride, cobalt nitrate, and cobalt acetate.
[0009] Based on the above technical solutions, preferably, the mass ratio of cobalt salt, 4,5-imidazolium dicarboxylic acid, and 4,4-bipyridine in step S1 is 1:0.5-2:0.5-2; for example, 1:0.5.0.5, 1:0.5.0.7, 1:0.5.0.9, 1:0.5.1, 1:0.5.1.2, 1:0.5.1.4, 1:0.5.1.6, 1:0.5.1.8, and 1:0.5:2 can be selected; but it is not limited to the listed values, and other unlisted values within the range are also applicable.
[0010] Based on the above technical solutions, preferably, the hydrothermal reaction conditions in step S1 are: temperature 120-180℃, for example, 120℃, 140℃, 160℃, 180℃; time 6-24 hours, for example, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h; but not limited to the listed values, other unlisted values within the range are also applicable.
[0011] In this step, the high temperature and high pressure environment provided by the hydrothermal reaction allows cobalt ions to undergo in-situ coordination self-assembly with 4,5-imidazolium dicarboxylic acid and 4,4-bipyridine ligands. Using the hydroxyl or defect sites on the surface of magnesite powder as nucleation centers, a three-dimensional porous cobalt-based MOF framework with abundant nitrogen-containing functional groups is grown in situ on the surface of magnesite powder. This not only significantly increases the specific surface area of the material, but also provides basic sites for subsequent reactions and pollutant adsorption.
[0012] Based on the above technical solutions, preferably, the volume concentration of the ethanol aqueous solution in step S2 is 50-90%, for example, 50%, 60%, 70%, 80%, or 90% can be selected; the mass ratio of 3-mercaptopropyltrimethoxysilane to magnesite powder is 1:10-20, for example, 1:10, 1:12, 1:14, 1:16, 1:18, or 1:20 can be selected; the stirring reaction temperature is 30-50℃, for example, 30℃, 40℃, or 50℃ can be selected; the reaction time is 3-5h, for example, 3h, 4h, or 5h can be selected; but it is not limited to the listed values, and other unlisted values within the range are also applicable; the magnesite powder is obtained by crushing magnesite to a particle size ≤200 mesh.
[0013] In this step, the hydrolytic condensation of 3-mercaptopropyltrimethoxysilane is utilized. The active silanol groups generated by the hydrolysis of silane undergo a dehydration condensation reaction with the hydroxyl groups on the surface of the pretreated magnesite powder to form a stable chemical bond. This allows highly active mercapto functional groups to be directionally grafted onto the material surface, providing the necessary nucleophilic sites for subsequent click chemistry reactions.
[0014] Based on the above technical solutions, preferably, in step S3, the mass ratio of triglycidyl phosphate to mercapto-magnesite powder is 1:1-3, for example, 1:1, 1:1.5, 1:2, 1:2.5, or 1:3; the heating reaction temperature is 50-80℃, for example, 50℃, 60℃, 70℃, or 80℃; and the reaction time is 4-12h, for example, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, or 12h, but not limited to the listed values. Other unlisted values within the range are also applicable.
[0015] In this step, triethylamine is used as an alkaline catalyst to allow the thiol groups on the thiolized magnesite powder and the epoxy groups of triglycidyl phosphate to undergo a chemical ring-opening reaction. While introducing phosphate groups with heavy metal complexing ability, new active hydroxyl groups are generated in situ, resulting in an organic-inorganic hybrid cross-linked network that has a synergistic removal effect on multiple pollutants.
[0016] Secondly, the present invention also proposes a functional magnesia composite material prepared by the above-mentioned method for preparing functional magnesia composite materials.
[0017] Thirdly, the present invention also proposes the application of the above-mentioned functional magnesium oxide composite material in wastewater treatment.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) This invention provides a functional magnesite composite material and its preparation method, realizing the comprehensive utilization of magnesite and having potential social and economic benefits. By introducing specific functional groups on the surface of magnesite powder through chemical modification, the adsorption performance and stability of the material are significantly improved. The method is simple and the reaction conditions are mild. The resulting composite material has a high specific surface area, abundant active sites and excellent chemical stability, and can be widely used in the field of wastewater treatment. Compared with ordinary magnesite composite materials, the composite material prepared by this invention has adjustable functions, low cost and is easy to scale up, with significant technical and economic advantages.
[0019] 2) The preparation of the functional magnesite composite material of this invention first involves loading cobalt-based MOF material onto magnesite powder via a hydrothermal reaction. On one hand, the three-dimensional porous structure of the MOF material significantly increases the specific surface area of the composite material, providing more active adsorption sites and preventing the agglomeration of magnesite powder in water. On the other hand, the 4,5-imidazolium dicarboxylic acid and 4,4-bipyridine ligands in the MOF framework introduce abundant nitrogen-containing heterocyclic functional groups such as imidazolium and pyridine. These nitrogen-containing heterocyclic functional groups are effective for the adsorption of heavy metal ions Pb. 2+ Cd 2+ Highly efficient adsorption is achieved through coordination, while the removal of organic pollutants such as dyes is mainly achieved through physicochemical processes such as π-π stacking, electrostatic attraction, and pore trapping. This multi-mechanism synergistic adsorption characteristic gives the modified magnesia composite material a broad-spectrum and highly efficient purification performance in the field of water treatment. Furthermore, introducing active thiol groups onto its surface not only facilitates the introduction of thiol groups, which is beneficial for subsequent reactions, but also allows for the introduction of sulfur, which enhances the composite material's ability to adsorb Hg. 2+ Pb 2+ Cd 2+ The specific chelating ability of heavy metal ions is utilized, and finally, through the chemical ring-opening reaction between triglycidyl phosphate and the mercapto groups on the material surface, a dense organic-inorganic hybrid cross-linked network is constructed on the surface of the magnesia composite material, effectively preventing the loss of active components. This process not only introduces phosphate groups with complexing ability for heavy metal ions, but also generates a large number of new hydrophilic active hydroxyl groups in situ with the ring-opening of epoxy. These newly introduced oxygen- and phosphorus-containing functional groups, together with sulfur elements and imidazole / pyridine in the MOF framework, construct a multi-coordination synergistic system, thereby significantly improving the mass transfer rate, structural stability, and broad-spectrum capture ability of various heavy metal ions in complex water bodies. Detailed Implementation
[0020] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.
[0021] Example 1 A method for preparing a functional magnesium oxide composite material includes the following steps: S1. Add 10g of cobalt nitrate hexahydrate, 5g of 4,5-imidazolium dicarboxylic acid and 5g of 4,4-bipyridine to 200mL of water, adjust the pH to 8.5 with sodium hydroxide solution, add 10g of magnesite powder pulverized to 200 mesh, and ultrasonically disperse to form a suspension. Transfer the suspension to a hydrothermal reactor and react at 150℃ for 12 hours. After the reaction is completed, cool to room temperature, centrifuge, and the precipitate is washed with water and dried to obtain pretreated magnesite powder. S2. Disperse 10g of pretreated magnesite powder in 100mL of 70% ethanol aqueous solution, add 1g of 3-mercaptopropyltrimethoxysilane, and stir mechanically at 40℃ for 4 hours. After the reaction is completed, filter, collect the solid product, wash with anhydrous ethanol, and vacuum dry to obtain mercapto-modified magnesite powder. S3. Add 5g of mercapto-modified magnesite powder to 100mL of acetone, add 10g of triglycidyl phosphate, and then add 0.5g of triethylamine as a catalyst. Heat and reflux at 65℃ for 8 hours. After the reaction is complete, filter, wash thoroughly with acetone to remove unreacted monomers, and dry under vacuum at 60℃ to obtain the functional magnesite composite material.
[0022] Example 2 A method for preparing a functional magnesium oxide composite material includes the following steps: S1. Add 10g of cobalt chloride hexahydrate, 10g of 4,5-imidazolium dicarboxylic acid and 10g of 4,4-bipyridine to 200mL of water, adjust the pH to 9, add 10g of magnesite powder pulverized to 300 mesh and mix to form a suspension. Perform hydrothermal reaction at 180℃ for 6 hours. After the reaction is completed, cool to room temperature, centrifuge and separate. The precipitate is washed with water and dried to obtain pretreated magnesite powder. S2. Disperse 10g of pretreated magnesite powder in 100mL of 90% ethanol aqueous solution, add 0.5g of 3-mercaptopropyltrimethoxysilane, stir and react at 50℃ for 3 hours, filter, collect the solid product, wash with anhydrous ethanol, and vacuum dry to obtain mercapto-modified magnesite powder. S3. Add 5g of mercapto-modified magnesite powder to 100mL of acetone, add 5g of triglycidyl phosphate, add 0.3g of triethylamine catalyst, heat at 80℃ for 4 hours, cool, filter, collect the solid product, wash and dry to obtain the functional magnesite composite material.
[0023] Example 3 A method for preparing a functional magnesium oxide composite material includes the following steps: S1. Add 10g of cobalt acetate tetrahydrate, 20g of 4,5-imidazolium dicarboxylic acid and 20g of 4,4-bipyridine to 200mL of water, adjust the pH to 8, add 10g of magnesite powder pulverized to 200 mesh and mix to form a suspension. Perform hydrothermal reaction at 120℃ for 24 hours. After the reaction is completed, cool to room temperature, centrifuge and separate. The precipitate is washed with water and dried to obtain pretreated magnesite powder. S2. Disperse 10g of pretreated magnesite powder in 100mL of 50% ethanol aqueous solution, add 2g of 3-mercaptopropyltrimethoxysilane, stir and react at 30℃ for 5 hours, filter and collect the solid product, wash with anhydrous ethanol, and vacuum dry to obtain mercapto-modified magnesite powder. S3. Add 5g of mercapto-modified magnesite powder to 100mL of acetone, add 15g of triglycidyl phosphate, add 0.8g of triethylamine catalyst, heat at 50℃ for 12 hours, cool, filter, collect the solid product, wash and dry to obtain the functional magnesite composite material.
[0024] Comparative Example 1 A method for preparing a functional magnesium oxide composite material is similar to that in Example 1, except that triglycidyl phosphate is not added. The method specifically includes the following steps: S1. Add 10g of cobalt nitrate hexahydrate, 5g of 4,5-imidazolium dicarboxylic acid and 5g of 4,4-bipyridine to 200mL of water, adjust the pH to 8.5, add 10g of magnesite powder pulverized to 200 mesh, ultrasonically disperse evenly, and hydrothermally react at 150℃ for 12 hours. After the reaction is completed, cool to room temperature, centrifuge, and the precipitate is washed with water and dried to obtain pretreated magnesite powder. S2. Disperse 10g of pretreated magnesite powder in 100mL of 70% (v / v) ethanol aqueous solution, add 1g of 3-mercaptopropyltrimethoxysilane, and react with mechanical stirring at 40℃ for 4 hours. After the reaction is complete, filter, wash and dry to obtain the functional magnesite composite material.
[0025] Comparative Example 2 A method for preparing a functional magnesium oxide composite material is similar to that in Example 1, except that the triglycidyl phosphate is physically mixed, and specifically includes the following steps: S1. Add 10g of cobalt nitrate hexahydrate, 5g of 4,5-imidazolium dicarboxylic acid and 5g of 4,4-bipyridine to 200mL of water, adjust the pH to 8.5 with sodium hydroxide solution, add 10g of magnesite powder pulverized to 200 mesh, and ultrasonically disperse to form a suspension. Transfer the suspension to a hydrothermal reactor and react at 150℃ for 12 hours. After the reaction is completed, cool to room temperature, centrifuge, and the precipitate is washed with water and dried to obtain pretreated magnesite powder. S2. Disperse 10g of pretreated magnesite powder in 100mL of 70% ethanol aqueous solution, add 1g of 3-mercaptopropyltrimethoxysilane, and stir mechanically at 40℃ for 4 hours. After the reaction is completed, filter, wash with anhydrous ethanol, and vacuum dry to obtain mercapto-modified magnesite powder. S3. Mix 5g of mercapto-modified magnesite powder and 10g of triglycidyl phosphate evenly to obtain the functional magnesite composite material.
[0026] Comparative Example 3 A method for preparing a functional magnesia composite material is similar to that in Example 1, except that the functional magnesia composite material is a MOF material supported on magnesia ore powder, and specifically includes the following steps: 10g of cobalt nitrate hexahydrate, 5g of 4,5-imidazolium dicarboxylic acid and 5g of 4,4-bipyridine were added to 200mL of water, the pH was adjusted to 8.5, and 10g of magnesite powder pulverized to 200 mesh was added. The mixture was then subjected to a hydrothermal reaction at 150℃ for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, and the precipitate was washed with water and dried to obtain the functional magnesite composite material.
[0027] Performance testing 2g of the functional magnesia composite materials obtained in Examples 1-3 and Comparative Examples 1-3 were added to 200mL of the same batch of dyeing and printing wastewater, respectively, in seven beakers. The mixtures were stirred at 30℃ for 1 day, and then allowed to stand. The chemical oxygen demand (COD), suspended solids (SS), decolorization rate, and heavy metal ion removal rate of the dyeing and printing wastewater before and after the addition of the functional magnesia composite materials were measured. COD was determined according to HJ828-2017 "Determination of Chemical Oxygen Demand in Water - Dichromate Method," and SS was determined according to GB11901-1989 "Determination of Suspended Solids in Water - Gravimetric Method." The decolorization rate was determined using a UV-Vis spectrophotometer. The test results are shown in Table 1. Table 1. Test results of adsorption performance of functional magnesium oxide composite materials
[0028] As can be seen from the experimental results in Table 1, the functional magnesium oxide composite material prepared by this invention has good wastewater treatment capabilities and good broad-spectrum adsorption properties.
[0029] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.
Claims
1. A method for preparing a functional magnesium oxide composite material, characterized in that, Includes the following steps: S1. Add cobalt salt, 4,5-imidazolium dicarboxylic acid and 4,4-bipyridine to water, adjust the pH to 8-9, add magnesite powder to form a suspension, and carry out a hydrothermal reaction to obtain pretreated magnesite powder. S2. Disperse the pretreated magnesite powder in an aqueous ethanol solution, add 3-mercaptopropyltrimethoxysilane and stir to react to obtain mercapto-modified magnesite powder; S3. Thiolized magnesite powder and triglycidyl phosphate are added to acetone and heated with triethylamine as a catalyst to obtain the functional magnesite composite material.
2. The functional magnesium oxide composite material according to claim 1, characterized in that: In step S1, the cobalt salt is at least one of cobalt chloride, cobalt nitrate, and cobalt acetate.
3. The functional magnesium oxide composite material according to claim 1, characterized in that: In step S1, the mass ratio of cobalt salt, 4,5-imidazolium dicarboxylic acid, and 4,4-bipyridine is 1:0.5-2:0.5-2.
4. The functional magnesium oxide composite material according to claim 1, characterized in that: The hydrothermal reaction conditions in step S1 are: temperature 120-180℃, time 6-24 hours.
5. The functional magnesium oxide composite material according to claim 1, characterized in that: In step S2, the mass ratio of 3-mercaptopropyltrimethoxysilane to magnesite powder is 1:10-20.
6. The functional magnesium oxide composite material according to claim 1, characterized in that: The stirring reaction temperature is 30-50℃, and the reaction time is 3-5h; the magnesite powder is obtained by crushing magnesite to a particle size ≤200 mesh.
7. The functional magnesium oxide composite material according to claim 1, characterized in that: In step S3, the mass ratio of triglycidyl phosphate to mercapto-modified magnesite powder is 1:1-3.
8. The functional magnesium oxide composite material according to claim 1, characterized in that: In step S3, the heating reaction temperature is 50-80℃, and the reaction time is 4-12h.
9. A functional magnesium oxide composite material, characterized in that: It is prepared by the preparation method described in any one of claims 1-8.
10. The application of the functional magnesium oxide composite material of claim 9 in wastewater treatment.