Method for synthesizing zirconium-modified P-type molecular sieve by taking fly ash as raw material through one-step method and product
The zirconium-modified P-type molecular sieve was synthesized by a one-step method under mechanochemical action, which solved the problem of complicated and time-consuming steps in the synthesis of molecular sieves from fly ash, achieved high-efficiency and low-energy As(V) adsorption effect, and broadened the pH application range.
Patent Information
- Application Number
- CN202510939018.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-09-19
AI Technical Summary
The existing method of synthesizing molecular sieves using fly ash as raw material is cumbersome, time-consuming and energy-intensive, and it is difficult to effectively remove As(V) in the form of anions. The traditional ion exchange method requires multiple calcinations and washings, which limits large-scale production.
A one-step method was adopted to achieve fly ash activation, metal doping and molecular sieve crystal formation by mixing fly ash, diatomaceous earth and zirconium solution through ball milling under the action of mechanochemistry, which simplified the synthesis steps, reduced energy consumption and improved the adsorption capacity of As(V).
The zirconium-modified P-type molecular sieve synthesized in one step has zirconium ions evenly distributed under the action of mechanochemistry, which improves the removal ability of As(V), shortens the synthesis time and reduces energy consumption. It has efficient adsorption performance and a wide pH range of application.
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Figure CN120664556A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of comprehensive resource utilization, and in particular to a method for synthesizing zirconium-modified P-type molecular sieves in one step using fly ash as a raw material, and a product thereof. Background Art
[0002] Fly ash, the fine dust collected from the flue gases of coal-fired power plants and urban central heating boilers, is considered an industrial solid waste. Improper handling of fly ash can cause soil pH imbalances, dust and haze, and heavy metal contamination of water, all of which can cause severe environmental damage. Because fly ash, an industrial solid waste, primarily consists of Si and Al, it can be used as an inexpensive raw material for synthesizing molecular sieves. The synthesis of molecular sieves using fly ash as a raw material has been extensively researched.
[0003] Since conventional synthetic molecular sieves primarily remove heavy metal ions from water through cation exchange, their removal efficiency for As(V), which primarily exists as anions in solution, is relatively low. Therefore, it is necessary to introduce transition metals (such as Zr and La) with an affinity for As(V) into the molecular sieve to improve its ability to adsorb and select As(V). Currently, the primary method for preparing metal-modified molecular sieves using fly ash as a raw material is ion exchange. Because Si and Al in fly ash primarily exist as mullite and quartz phases, the ion exchange method for preparing metal-modified molecular sieves requires calcining and activating the fly ash, followed by hydrothermal synthesis of the molecular sieve. Ion exchange technology is then used to adjust the type of countercations outside the molecular sieve framework, and the exchanged product is finally calcined and washed. Therefore, the ion exchange method not only has many steps and is time-consuming, but also consumes a high amount of energy during calcination and activation, hindering the large-scale production of metal-modified molecular sieves with adsorption properties using fly ash as a raw material. Summary of the Invention
[0004] In view of the above shortcomings, the technical solution of the present invention provides a method and product for synthesizing zirconium-modified P-type molecular sieves in one step using fly ash as raw material. A fly ash-based zirconium-modified P-type molecular sieve with high adsorption capacity for As(V) is synthesized by a one-step method under the action of mechanochemistry. The activation of fly ash, metal ion doping and the formation of molecular sieve crystals are achieved in a one-step synthesis process. This method not only avoids the calcination activation of fly ash and effectively reduces energy consumption, but also simplifies the synthesis steps and effectively shortens the synthesis time. Moreover, under the action of mechanochemistry, the introduced metal ions can be doped into different positions of the molecular sieve, thereby broadening the pH range of the metal-modified molecular sieve for As(V) adsorption and effectively improving its ability to remove As(V).
[0005] To this end, the purpose of the technical solution of the present invention is to provide a method and product for synthesizing zirconium-modified P-type molecular sieves in one step using fly ash as raw material, so as to solve the problems of complex process, long preparation time and high energy consumption in the molecular sieve modification process.
[0006] According to a first aspect of the technical solution of the present invention, a method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material is provided, comprising the following steps:
[0007] (1) Raw material mixing: Fly ash, diatomaceous earth, and sodium hydroxide are added into a ball mill according to a specific ratio;
[0008] (2) adjusting the concentration of the zirconium-containing solution: dissolving the zirconium-containing compound in deionized water and stirring to fully dissolve it to obtain a zirconium-containing solution;
[0009] (3) ball milling: adding the zirconium-containing solution to the ball milling tank in step (1), and using a ball mill to perform ball milling to obtain a gel solution;
[0010] (4) Filtration and washing: Cool the gel solution to room temperature, filter to obtain a solid residue, and wash the solid residue several times with deionized water;
[0011] (5) Taking out the product obtained in step (4), drying it for a period of time, and obtaining a zirconium-modified P-type molecular sieve.
[0012] Furthermore, in the step (1), the fly ash is sieved through a 100-mesh sieve.
[0013] Furthermore, in step (1), the fly ash is industrial solid waste fly ash.
[0014] Furthermore, in step (1), the mass ratio of fly ash, diatomaceous earth and sodium hydroxide is m(FA):m(DE):m(NaOH)=3:1.62:4.25.
[0015] Furthermore, in step (2), the zirconium-containing compound is zirconium oxychloride octahydrate.
[0016] Furthermore, in step (2), the concentration of the zirconium-containing solution is 0.1-0.2 mol / L.
[0017] Furthermore, in the step (3), the ball milling temperature is 110-150° C., the ball milling speed is 1800-2000 rpm, and the ball milling time is 6-8 h.
[0018] Furthermore, in the step (3), after the zirconium-containing solution is added to the ball milling jar in the step (1), a certain proportion of large, medium and small balls are added according to the ball-to-powder ratio, and ball milling is performed using a ball mill;
[0019] Among them, the ball-to-powder ratio is 15:1, and the ratio of large, medium and small balls is 2:3:5.
[0020] Furthermore, in the step (4), the solid residue is washed 3-4 times with deionized water.
[0021] Furthermore, in step (5), drying is performed in a constant temperature drying oven.
[0022] Furthermore, in the step (5), the drying temperature is 80-90° C., and the drying time is 20-24 hours.
[0023] According to the second aspect of the technical solution of the present invention, a zirconium-modified P-type molecular sieve is provided, wherein the zirconium-modified P-type molecular sieve is prepared by the one-step synthesis method of zirconium-modified P-type molecular sieve using fly ash as raw material according to any of the above aspects.
[0024] Beneficial technical effects of the present invention:
[0025] The method of the present invention breaks through the technical limitations of traditional step-by-step synthesis and couples the fly ash activation, metal doping and molecular sieve crystallization processes with a mechanochemical reaction system. Compared with the traditional ion exchange method, the one-step synthesis method can reduce the synthesis time from 56h to 6h and the energy consumption from 41.7kW·h to 8.7kW·h. Under the mechanochemical action of the one-step method, the introduced Zr 4+ Ions can be evenly distributed in the pores and framework of the molecular sieve, while the ion exchange method mainly converts Zr 4+ Ion exchange into the pores, so the introduction of Zr in the zirconium-modified P-type molecular sieve synthesized in one step 4+ The ions can be evenly distributed in the molecular sieve, and the amount of zirconium introduced reaches 12.90%, which is higher than the modified molecular sieve synthesized by ion exchange (10.01%). At the same time, under the mechanochemical action of the one-step method, the crystallinity, specific surface area and average pore size of the synthesized zirconium-modified P-type molecular sieve are 88.2%, 142.559m3 and 142.57m3 respectively. 2 / g and 5.743nm; while the crystallinity, specific surface area and average pore size of the zirconium-modified P-type molecular sieve synthesized by the traditional ion exchange method are 72.8%, 126.509m 2 / g and 6.484nm. Due to the high Zr 4+ ion introduction amount, crystallinity, specific surface area, and more uniform Zr 4+The ion distribution and pore system result in an As(V) removal capacity of 229.320 mg / g, which is 9.8% higher than that of zirconium-modified molecular sieves synthesized by ion exchange. The optimal synthesis conditions for the one-step synthesis of zirconium-modified P-type molecular sieves from fly ash are a zirconium solution concentration of 0.15 mol / L, a ball milling temperature of 130°C, a ball milling time of 6 hours, and a ball milling speed of 2000 rpm. This method uses a mechanochemical method to synthesize a P-type molecular sieve with a high zirconium content. This molecular sieve has a high adsorption capacity for As(V) and can achieve efficient and low-energy utilization of solid waste resources. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 The figure is a process flow chart of a method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to the technical solution of the present invention.
[0027] Figure 2 This is a process flow diagram for the synthesis of zirconium-modified P-type molecular sieves using the traditional ion exchange method. DETAILED DESCRIPTION
[0028] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite demarcation of the protection scope of the present invention.
[0029] The technical solution of the present invention provides a one-step method and product for synthesizing zirconium-modified P-type molecular sieves using fly ash as the primary raw material. Using fly ash, a solid waste generated by coal-fired power plants, as the primary raw material, this method significantly reduces energy and time consumption. The preparation steps include raw material mixing, ball milling, product filtration, washing, and drying, effectively shortening the process steps and significantly reducing energy and time consumption for the synthesis. Furthermore, the zirconium-modified molecular sieve is directly prepared by ball milling fly ash, diatomaceous earth, and a sodium hydroxide zirconium solution using an external heat source to complete fly ash activation, metal doping, and molecular sieve crystallization.
[0030] Here, the zirconium-modified P-type subsieve is directly prepared in one step by mixing a zirconium solution with fly ash, diatomaceous earth, and sodium hydroxide, adjusting the temperature of a ball mill, and then achieving activation, metal doping, and crystallization through ball milling.
[0031] Specifically, the technical solution of the present invention first provides a one-step method for synthesizing zirconium-modified P-type molecular sieve using fly ash as raw material, such as Figure 1 As shown, the following steps are included:
[0032] (1) Raw material mixing: Fly ash, diatomaceous earth and sodium hydroxide are added into the ball mill according to a specific ratio.
[0033] In a preferred embodiment, in step (1), the fly ash is sieved through a 100-mesh sieve.
[0034] In a preferred embodiment, in step (1), the fly ash is industrial solid waste fly ash.
[0035] In a preferred embodiment, in step (1), the mass ratio of fly ash, diatomaceous earth and sodium hydroxide is m(FA):m(DE):m(NaOH)=3:1.62:4.25, wherein diatomaceous earth plays the role of supplementing silicon source, and sodium hydroxide can not only activate quartz and mullite in fly ash, but also provide Na + ion.
[0036] (2) Adjusting the concentration of the zirconium-containing solution: dissolving the zirconium-containing compound in deionized water and stirring to fully dissolve it to obtain a zirconium-containing solution.
[0037] In a preferred embodiment, in step (2), the zirconium-containing compound is a readily soluble active metal salt zirconium oxychloride octahydrate.
[0038] In a preferred embodiment, in step (2), the concentration of the zirconium-containing solution is in the range of 0.1-0.2 mol / L, and the zirconium-modified molecular sieve cannot be synthesized by adding a zirconium solution with too low or too high concentration.
[0039] (3) Ball milling: adding the zirconium-containing solution to the ball milling jar in step (1), and performing ball milling using a ball mill to obtain a gel solution.
[0040] In a preferred embodiment, in step (3), the ball milling temperature of the ball mill is 110-150°C, the ball milling speed is 1800-2000 rpm, and the ball milling time is 6-8 hours. If the ball milling temperature is too low, molecular sieve cannot be synthesized, while if the ball milling temperature is too high, energy is wasted; if the ball milling speed is too low, the raw materials cannot be activated, while if the ball milling speed is too high, energy is wasted; if the ball milling time is too short, molecular sieve cannot be synthesized, while if the ball milling time is too long, the crystallization effect will be affected.
[0041] In a preferred embodiment, in step (3), after adding the zirconium-containing solution to the ball milling jar in step (1), a certain proportion of large, medium and small balls are added according to the ball-to-powder ratio, and ball milling is performed using a ball mill;
[0042] The ball-to-powder ratio is 15:1, and the ratio of large, medium, and small balls is 2:3:5. A ball-to-powder ratio that is too low or too high will affect the grinding effect and thus the synthesis effect. A high ratio of large, medium, and small balls will result in insufficient grinding, while a low ratio of large, medium, and small balls will result in too fine a particle size of fly ash, which is not conducive to the synthesis of molecular sieves.
[0043] (4) Filtration and washing: The gel solution was cooled to room temperature, and solid residues were obtained by filtration. The solid residues were washed several times with deionized water.
[0044] In a preferred embodiment, in step (4), the solid residue is washed 3-4 times with deionized water.
[0045] (5) Taking out the product obtained in step (4), drying it for a period of time, and obtaining a zirconium-modified P-type molecular sieve.
[0046] In a preferred embodiment, in step (5), the drying process is carried out in a constant temperature drying oven.
[0047] In a preferred embodiment, in step (5), the drying temperature is 80-90°C and the drying time is 20-24 hours. If the drying temperature is too low, the evaporation of water at low temperatures will be slow, which may aggravate the agglomeration of the molecular sieve particles, resulting in uneven particle size distribution, affecting mass transfer efficiency and reaction performance. If the drying temperature is too high, energy will be wasted. If the drying time is too short, the drying effect will be affected, and if the drying time is too long, energy will be wasted.
[0048] The technical solution of the present invention also provides a zirconium-modified P-type molecular sieve, wherein the zirconium-modified P-type molecular sieve is prepared by the above-mentioned one-step method for synthesizing zirconium-modified P-type molecular sieve using fly ash as raw material.
[0049] Example 1
[0050] A method for synthesizing zirconium-modified P-type molecular sieves from fly ash in one step, characterized by comprising the following steps:
[0051] (1) Raw material mixing: fly ash, diatomaceous earth, and sodium hydroxide are added into a ball mill according to a specific ratio, wherein the fly ash is passed through a 100-mesh sieve;
[0052] (2) Adjusting the concentration of the zirconium solution: dissolving zirconium oxychloride octahydrate in deionized water and stirring until fully dissolved to adjust the concentration to 0.15 mol / L;
[0053] (3) ball milling: adding the 0.1 mol / L zirconium-containing solution in step (2) to the ball milling jar in step (2), and adding large, medium and small balls in a ratio of 2:3:5 at a ball-to-powder ratio of 15:1, and using a ball mill to perform ball milling at a ball milling temperature of 110° C., a ball milling speed of 2000 rpm, and a ball milling time of 8 h;
[0054] (4) Filtration and washing: The gel solution obtained in step (3) is cooled to room temperature, filtered to obtain a solid residue, and the residue is washed 3-4 times with deionized water;
[0055] (5) The product obtained in step (4) was taken out and dried in a constant temperature drying oven at 80° C. for 24 h to obtain a zirconium-modified P-type molecular sieve.
[0056] Example 2
[0057] (1) Raw material mixing: fly ash, diatomaceous earth, and sodium hydroxide are added into a ball mill according to a specific ratio, wherein the fly ash is passed through a 100-mesh sieve;
[0058] (2) Adjusting the concentration of the zirconium solution: dissolving zirconium oxychloride octahydrate in deionized water and stirring until fully dissolved to adjust the concentration to 0.15 mol / L;
[0059] (3) ball milling: adding the 0.1 mol / L zirconium-containing solution in step (2) to the ball milling jar in step (2), and adding large, medium and small balls in a ratio of 2:3:5 at a ball-to-powder ratio of 15:1, and using a ball mill to perform ball milling at a ball milling temperature of 130° C., a ball milling speed of 2000 rpm, and a ball milling time of 6 h;
[0060] (4) Filtration and washing: The gel solution obtained in step (3) is cooled to room temperature, filtered to obtain a solid residue, and the residue is washed 3-4 times with deionized water;
[0061] (5) The product obtained in step (4) was taken out and dried in a constant temperature drying oven at 80° C. for 24 h to obtain a zirconium-modified P-type molecular sieve.
[0062] Example 3
[0063] (1) Raw material mixing: fly ash, diatomaceous earth, and sodium hydroxide are added into a ball mill according to a specific ratio, wherein the fly ash is passed through a 100-mesh sieve;
[0064] (2) Adjusting the concentration of the zirconium solution: dissolving zirconium oxychloride octahydrate in deionized water and stirring until fully dissolved to adjust the concentration to 0.15 mol / L;
[0065] (3) ball milling: adding the 0.1 mol / L zirconium-containing solution in step (2) to the ball milling jar in step (2), and adding large, medium and small balls in a ratio of 2:3:5 at a ball-to-powder ratio of 15:1, and using a ball mill to perform ball milling at a ball milling temperature of 150° C., a ball milling speed of 2000 rpm, and a ball milling time of 8 h;
[0066] (4) Filtration and washing: The gel solution obtained in step (3) is cooled to room temperature, filtered to obtain a solid residue, and the residue is washed 3-4 times with deionized water;
[0067] (5) The product obtained in step (4) was taken out and dried in a constant temperature drying oven at 80° C. for 24 h to obtain a zirconium-modified P-type molecular sieve.
[0068] The zirconium-modified P-type molecular sieve prepared in Example 1 was used as an example for detection and analysis. The maximum adsorption capacity of the prepared zirconium-modified P-type molecular sieve for As(V) can reach 185.35 mg / g, and the relative crystallinity calculated using Jade is 72.7%.
[0069] The zirconium-modified P-type molecular sieve prepared in Example 2 was used as an example for detection and analysis. The maximum adsorption capacity of the prepared zirconium-modified P-type molecular sieve for As(V) can reach 229.90 mg / g. The relative crystallinity calculated using Jade is 88.2%, and the zirconium content measured by ICP is 12.90%.
[0070] The zirconium-modified P-type molecular sieve prepared in Example 3 was used as an example for detection and analysis. The maximum adsorption capacity of the prepared zirconium-modified P-type molecular sieve for As(V) can reach 198.74 mg / g, and the relative crystallinity calculated using Jade is 75.1%.
[0071] Comparative Example
[0072] like Figure 2 As shown, the specific steps of synthesizing zirconium modified molecular sieves by traditional ion exchange method are:
[0073] (1) Synthesis of NaP molecular sieve
[0074] 3g of fly ash, 1.62g of diatomaceous earth and 4.25g of sodium hydroxide were thoroughly ground and mixed, placed in a crucible and calcined at 550°C for 2h. After cooling to room temperature, the obtained sample was ground through a 200-mesh sieve. Subsequently, deionized water and the above mixture were added to a beaker at a solid-liquid ratio of 1:5 and stirred for 2h. After aging for 0.5h, the slurry was poured into a polytetrafluoroethylene high-pressure reactor and placed in a constant temperature drying oven at 160°C for crystallization for 48h. The obtained product was filtered, washed and dried to obtain NaP molecular sieve.
[0075] (2) Synthesis of metal-modified molecular sieves
[0076] 3.00 g of the resulting NaP molecular sieve was immersed in 30 mL of a 0.1 M ZrOCl2 solution and magnetically stirred for 6 hours (25°C, 300 rpm) to complete the ion exchange. The reaction product was vacuum filtered and rinsed three times with deionized water. The product was then placed in a vacuum drying oven at 80°C for 24 hours to yield the zirconium-modified molecular sieve.
[0077] The zirconium-modified molecular sieve prepared in the comparative example was used as an example for detection and analysis. The maximum adsorption capacity of the prepared zirconium-modified molecular sieve for As(V) was 88.581 mg / g.
[0078] In summary, the technical solution of the present invention breaks through the technical limitations of traditional step-by-step synthesis and couples the fly ash activation, metal doping and molecular sieve crystallization processes into a mechanochemical reaction system. Compared with the traditional ion exchange method, the zirconium-modified P-type molecular sieve synthesized by the one-step method has a more regular crystal structure and higher Zr 4+ Ion introduction amount, more uniform Zr 4+ The ion distribution, as well as the higher specific surface area and uniform pore system, have a more efficient removal ability for As(V) in solution. The synthesized molecular sieve has a zirconium content of up to 12.90wt%, and is an adsorbent with high adsorption capacity for As(V) in solution, with a maximum adsorption capacity of up to 229.32mg / g, and has a wide pH application range and multiple recycling performance. The synthesis method of the present invention is simple, effectively reducing the energy consumption and time consumption of the synthesis process, and the synthesized molecular sieve has a high zirconium content and a high selective adsorption capacity for As(V).
[0079] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.
Claims
1. A one-step method for synthesizing zirconium-modified P-type molecular sieve using fly ash as raw material, characterized in that: The following steps are involved: (1) Raw material mixing: Fly ash, diatomaceous earth, and sodium hydroxide are added into a ball mill according to a specific ratio; (2) adjusting the concentration of the zirconium-containing solution: dissolving the zirconium-containing compound in deionized water and stirring to fully dissolve it to obtain a zirconium-containing solution; (3) ball milling: adding the zirconium-containing solution to the ball milling tank in step (1), and using a ball mill to perform ball milling to obtain a gel solution; (4) Filtration and washing: Cool the gel solution to room temperature, filter to obtain a solid residue, and wash the solid residue several times with deionized water; (5) Taking out the product obtained in step (4), drying it for a period of time, and obtaining a zirconium-modified P-type molecular sieve.
2. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (1), the fly ash is industrial solid waste fly ash.
3. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (1), the mass ratio of fly ash, diatomaceous earth and sodium hydroxide is m(FA):m(DE):m(NaOH)=3:1.62:4.
25.
4. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (2), the zirconium-containing compound is zirconium oxychloride octahydrate.
5. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 4, characterized in that: In the step (2), the concentration of the zirconium-containing solution is 0.1-0.2 mol / L.
6. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (3), the ball milling temperature is 110-150° C., the ball milling speed is 1800-2000 rpm, and the ball milling time is 6-8 h.
7. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (3), after adding the zirconium-containing solution to the ball milling jar in the step (1), a certain proportion of large, medium and small balls are added according to the ball-to-powder ratio, and ball milling is performed using a ball mill; Among them, the ball-to-powder ratio is 15:1, and the ratio of large, medium and small balls is 2:3:
5.
8. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (4), the solid residue is washed 3-4 times with deionized water.
9. The method for synthesizing zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to claim 1, characterized in that: In the step (5), drying is performed in a constant temperature drying oven; Wherein, in the step (5), the drying temperature is 80-90°C and the drying time is 20-24h.
10. A zirconium-modified P-type molecular sieve, characterized in that: The zirconium-modified P-type molecular sieve is prepared by the method for synthesizing the zirconium-modified P-type molecular sieve in one step using fly ash as raw material according to any one of claims 1 to 9.