A method for preparing aerogel material from red soil and application thereof
By preparing porous aerogels using red soil as raw material, the problem of high cost in aerogel preparation has been solved, realizing the high-value utilization of red soil and effective inhibition of phosphorus in sediments. The prepared aerogels have high-efficiency adsorption properties and are suitable for large-scale industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2023-11-06
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, the high cost of raw materials for preparing aerogel materials limits their large-scale application. At the same time, the high value of red soil has not been fully utilized, and it is difficult to effectively suppress the release of phosphorus from sediments.
Porous aerogels were prepared using red soil as raw material through pretreatment, high-temperature alkali fusion, acid leaching, and aging. These aerogels were used as phosphorus passivating agents for the adsorption of phosphorus in sediments. The specific steps included impurity removal and drying, grinding, mixing with an alkali source and reacting at high temperature, acid leaching, and solvent exchange. The parameters were optimized to improve efficiency.
The prepared aerogel has a large specific surface area and high porosity, which can quickly and effectively adsorb phosphorus pollutants in sediments and water. It is low in cost and simple in process, making it suitable for large-scale industrial production. It solves the problem of high raw material cost and realizes the high-value utilization of red soil.
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Figure CN117599695B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental ecological restoration technology, specifically relating to a method for preparing aerogel materials using red soil as raw material and its application. Background Technology
[0002] Currently, many technologies for controlling endogenous phosphorus release have been developed. Among them, in-situ sediment cover is a promising sediment pollutant control technology both domestically and internationally. In-situ cover involves spreading a material with certain adsorption and passivation effects on the sediment surface to form a cover layer, or using equipment to mix it with the sediment to inhibit the release of phosphorus from the sediment. The key to remediating sediments using in-situ cover is the selection of the phosphorus passivating agent. Generally, materials with a large specific surface area and high porosity are selected to adsorb phosphates in the sediment and water.
[0003] Aerogels are porous solid materials with a gaseous dispersed phase, possessing a unique structure of large specific surface area and high porosity, making them a potential candidate for phosphorus passivation agents. As the definition of aerogels continues to broaden, research on aerogels is increasing. In recent years, numerous studies have prepared different types of aerogels and applied them as adsorbents in various fields. Researchers have successfully synthesized porous aerogels using fly ash and kaolin, while red soil, which also contains abundant SiO2 and Al2O3, shows great potential for aerogel preparation. Currently, the high cost of raw materials for aerogel preparation, such as TEOS and sodium silicate, limits the large-scale application of aerogels. Using red soil as a raw material for aerogel preparation would not only significantly reduce raw material costs but also facilitate the high-value utilization of red soil. Summary of the Invention
[0004] This invention addresses the problem of endogenous phosphorus pollution and the availability of inexpensive red soil. It provides a method for preparing aerogel materials using red soil as raw material and its application. Red soil-based porous aerogels are used as phosphorus desensitizers to effectively inhibit the release of phosphorus from sediments.
[0005] This invention is specifically implemented through the following technical solution:
[0006] This invention provides a method for preparing aerogel materials using red soil as raw material, comprising the following steps:
[0007] S1. Pretreatment: Take red soil, remove impurities, dry, grind and sieve it to obtain pretreated red soil for later use;
[0008] S2, High-temperature alkali fusion: Pretreated red soil is mixed with an alkali source, then heated to react, and cooled after the reaction to obtain an alkali-fused solid;
[0009] S3, Acid leaching: Mix the alkali-fused solid with hydrochloric acid and stir until the reaction is complete to obtain a silicon-rich aluminum solution;
[0010] S4. Aging: Adjust the initial pH of the silicon-rich and aluminum-rich solution, allow it to age naturally, then exchange the solvent with anhydrous ethanol, filter, wash, and dry to obtain a porous aerogel.
[0011] Preferably, the drying of S1 includes air drying at room temperature for 3-6 days, followed by drying at 65-105℃ for 12-24 hours; grinding through a 100-200 mesh sieve to ensure a more complete alkali fusion reaction in the next step.
[0012] Preferably, the alkali source in S2 is one or two of NaOH, Na2CO3, Na2SiO3, NaHCO3, CaCO3, and KOH, and the mass ratio of the alkali source to the pretreated red soil is 1:(0.5-2.5).
[0013] Preferably, the heating reaction temperature in S2 is 350-900℃, the heating rate is 5-20℃ / min, and the reaction time is 60-180 min. By optimizing and adjusting various factors, the complete alkali-fusion reaction is ensured.
[0014] Preferably, the hydrochloric acid concentration in S3 is 2-6 M, the mixing and stirring speed is 300-400 rpm, the reaction temperature is 25-85℃, and the reaction time is 1-3 h. By optimizing and adjusting various factors, the leaching of the active ingredients is ensured to achieve the best effect.
[0015] Preferably, the initial pH of S4 is adjusted to 2.5-4.5; the aging temperature is 25-65℃, and the aging time is 24-48 h. Various factors are optimized to improve the yield and performance of the aerogel.
[0016] This invention also provides the application of the aerogel obtained by the above method in the remediation of endogenous phosphorus pollution in sediments.
[0017] Compared with the prior art, the beneficial effects of the present invention are:
[0018] The aerogel synthesized in this invention has excellent adsorption and fixation properties for phosphorus pollutants in sediments and water due to its abundant porosity and high specific surface area. In practical applications, it can be used as an environmental functional material to effectively address the problem of endogenous phosphorus pollution release from sediments.
[0019] The aerogel prepared by the present invention using red soil has the advantages of large specific area, high porosity, fast adsorption rate and large adsorption capacity. It has low preparation cost and simple process, and is suitable for large-scale industrial production. Attached Figure Description
[0020] Figure 1 This is a picture of actual red soil.
[0021] Figure 2 This is a picture of the synthesized aerogel.
[0022] Figure 3 This is a scanning electron microscope image of red soil.
[0023] Figure 4 This is a scanning electron microscope (SEM) image of the synthesized aerogel.
[0024] Figure 5 This is the XRD pattern of red soil.
[0025] Figure 6 This is the XRD pattern of the synthesized aerogel.
[0026] Figure 7 These are the XRD patterns of alkali-fused solids with different mass ratios of sodium hydroxide to pretreated red soil.
[0027] Figure 8 These are the XRD patterns of aerogels synthesized under different initial pH conditions.
[0028] Figure 9 These are the N2 adsorption-desorption curves of aerogels synthesized under different initial pH conditions.
[0029] Figure 10 These are Fourier transform infrared spectra of red soil and synthetic aerogel.
[0030] Figure 11 This is a graph showing the adsorption kinetics of phosphorus on the synthesized aerogel.
[0031] Figure 12 This is the adsorption isotherm diagram of phosphorus on the synthesized aerogel. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with embodiments. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0034] The red soil used in this embodiment of the invention was taken from a certain area in Ganzhou City, Jiangxi Province, and its main elemental analysis is shown in the table below:
[0035] Table 1
[0036]
[0037] Example 1
[0038] A method for preparing aerogel materials using red soil as raw material includes:
[0039] 1. Pretreatment: Remove surface vegetation, gravel and other impurities from red soil, air dry it at room temperature for 3 days, then put it in an oven at 80℃ for 24 hours, grind and sieve (100 mesh) for later use.
[0040] 2. High-temperature alkali fusion: Pretreated red soil and solid sodium hydroxide are mixed at a mass ratio of 1:1 and reacted in a muffle furnace at 650℃ (heating rate 10℃ / min) for 180 min. After the reaction is completed, the mixture is cooled to room temperature with the furnace, and then ground to obtain the alkali fused solid.
[0041] 3. Acid leaching: The alkali-fused solid and hydrochloric acid solution (5 M) are reacted on a magnetic stirrer for 2 hours at a solid-liquid ratio of 10:1 (mL / g) (mixing and stirring speed 400 rpm, reaction temperature 25℃). After the reaction, the solution is filtered to obtain a silicon-rich aluminum solution.
[0042] 4. Aging: Adjust the initial pH of the silicon-rich and aluminum-rich solution to 3, and let it age naturally at 25°C for 24 h. Then, exchange the solvent with anhydrous ethanol for 18 h. After filtration and washing, dry at 65°C for 12 h to obtain porous aerogel.
[0043] Example 2
[0044] The steps and parameters in this embodiment are the same as in embodiment 1, except that in step 2, solid sodium hydroxide and pretreated red soil are mixed at a mass ratio of 1.5:1.
[0045] Example 3
[0046] The steps and parameters in this embodiment are the same as in embodiment 1, except that in step 2, solid sodium hydroxide and pretreated red soil are mixed at a mass ratio of 1:1.5.
[0047] Example 4
[0048] The steps and parameters in this embodiment are the same as in embodiment 1, except that in step 2, solid sodium hydroxide and pretreated red soil are mixed at a mass ratio of 1:2.
[0049] Example 5
[0050] The steps and parameters in this embodiment are the same as in embodiment 1, except that in step 2, solid sodium hydroxide and pretreated red soil are mixed at a mass ratio of 1:2.5.
[0051] Example 6
[0052] The steps and parameters in this embodiment are the same as in Embodiment 1, except that the concentration of hydrochloric acid solution in step 3 is 2 M.
[0053] Example 7
[0054] The steps and parameters in this embodiment are the same as in Embodiment 1, except that the concentration of the hydrochloric acid solution in step 3 is 3 M.
[0055] Example 8
[0056] The steps and parameters in this embodiment are the same as in Embodiment 1, except that the concentration of hydrochloric acid solution in step 3 is 4 M.
[0057] Example 9
[0058] The steps and parameters in this embodiment are the same as in Embodiment 1, except that the concentration of the hydrochloric acid solution in step 3 is 6 M.
[0059] Example 10
[0060] The steps and parameters in this embodiment are the same as in Embodiment 1, except that in step 4, the initial pH of the silicon-rich aluminum solution is adjusted to 2.5.
[0061] Example 11
[0062] The steps and parameters in this embodiment are the same as in Embodiment 1, except that in step 4, the initial pH of the silicon-rich aluminum solution is adjusted to 3.5.
[0063] Example 12
[0064] The steps and parameters in this embodiment are the same as in embodiment 1, except that in step 4, the initial pH of the silicon-rich aluminum solution is adjusted to 4.
[0065] Example 13
[0066] The steps and parameters in this embodiment are the same as in Embodiment 1, except that in step 4, the initial pH of the silicon-rich aluminum solution is adjusted to 4.5.
[0067] By comparing the physical images before and after aerogel synthesis ( Figure 1 , 2 ), to observe the changes in aerogel morphology macroscopically; to characterize red soil and aerogel using XRD and SEM (). Figure 3 , 4 5, 6), analyze the changes in its phase composition and surface morphology; XRD tests were performed on the alkali-fused solids under different sodium hydroxide to pretreated red soil mass ratios ( Figure 7 The activation degree of red soil was determined by analyzing the diffraction peak intensities of nepheline and sodium silicate, and the optimal mass ratio of sodium hydroxide to red soil was obtained. The XRD patterns and N2 adsorption-desorption curves of aerogels synthesized under different initial pH conditions were analyzed. Figure 8, 9 The optimal initial pH for aging was determined by FT-IR testing of red soil and aerogel. Figure 10 ), and analyze the changes in its functional groups and valence bonds. Figure 11 , Figure 12 These are the adsorption kinetics diagram and adsorption isotherm diagram of phosphorus on aerogel.
[0068] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they are not intended to limit the present invention. It should be noted that various changes and modifications can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the concept and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing aerogel materials using red soil as raw material, characterized in that, Includes the following steps: S1. Pretreatment: Take red soil, remove impurities, dry, grind and sieve it to obtain pretreated red soil for later use; S2, High-temperature alkali fusion: Pretreated red soil is mixed with an alkali source, then heated to react, and cooled after the reaction to obtain an alkali-fused solid; The alkali source is one or two of NaOH, Na2CO3, Na2SiO3, NaHCO3, CaCO3, and KOH, and the mass ratio of the alkali source to the pretreated red soil is 1:(1-2); the heating reaction temperature is 350-900℃, the heating rate is 5-20℃ / min, and the reaction time is 60-180 min. S3, Acid leaching: Mix the alkali-fused solid with hydrochloric acid and stir until the reaction is complete to obtain a silicon-rich aluminum solution; The concentration of hydrochloric acid is 2-6 M, the mixing and stirring speed is 300-400 rpm, the reaction temperature is 25-85℃, and the reaction time is 1-3 h. S4. Aging: Adjust the initial pH of the silicon-rich and aluminum-rich solution, age it naturally, then exchange it with anhydrous ethanol, filter, wash and dry to obtain porous aerogel. The initial pH was adjusted to 2.5-4.5; the aging temperature was 25-65℃, and the time was 24-48 h.
2. The method for preparing aerogel from red soil according to claim 1, characterized in that, S1 drying includes air drying at room temperature for 3-6 days, followed by drying at 65-105℃ for 12-24 hours; grinding through a 100-200 mesh sieve.
3. The application of the aerogel obtained by the method described in claim 1 or 2 in the remediation of endogenous phosphorus pollution in sediments.