Preparation method and application of natural mineral-based molecular sieve based on response surface method optimization
By optimizing the process parameters for preparing molecular sieves from natural ores using the response surface methodology, removing impurities through acid treatment, and combining alkali melting and hydrothermal synthesis methods, the problems of low crystallinity and unsatisfactory adsorption performance of molecular sieves prepared from natural ores were solved, achieving efficient and low-cost wastewater treatment.
Patent Information
- Application Number
- CN202511934135.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-20
- Publication Date
- 2026-02-27
AI Technical Summary
In existing technologies, the preparation of molecular sieves from natural ores suffers from problems such as a silica-alumina ratio deviating from the target range, high impurity content, and unoptimized preparation process parameters. These issues result in low crystallinity and unsatisfactory adsorption performance of the molecular sieves. Furthermore, there is a lack of application of response surface methodology in optimizing the process of preparing molecular sieves from natural ores.
The process parameters for preparing molecular sieves from natural ores were optimized using response surface methodology. Impurities were removed by acid treatment, and the process was combined with alkali melting and hydrothermal synthesis methods to optimize factors such as mineral powder particle size, acid treatment pH, mass ratio, temperature, time, alkali melting mass ratio, temperature, time, and hydrothermal synthesis temperature and time, thereby preparing molecular sieves with high crystallinity and high adsorption capacity.
It significantly improves the crystallinity and adsorption performance of molecular sieves, reduces raw material costs, and provides a green and low-cost wastewater treatment technology suitable for deep treatment of wastewater from coal chemical, petrochemical, metallurgical and aquaculture industries.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of inorganic functional material preparation and adsorbent technology, and in particular to a preparation method of natural mineral-based molecular sieve based on response surface method optimization and application thereof. BACKGROUND
[0002] Molecular sieve is a kind of crystalline microporous material with regular three-dimensional pore structure, and the skeleton thereof is connected by SiO4 and AlO4 tetrahedrons through shared oxygen bridges. Since Al 3+ substitutes Si 4+ , a negative charge is generated in the skeleton, and Na + , K + , NH4 + and other exchangeable cations need to be introduced to maintain charge balance, thereby endowing the molecular sieve with excellent ion exchange, adsorption and catalytic properties. Molecular sieve is widely used in gas separation, petroleum and chemical industry, fine chemical industry and environmental governance field. In the field of wastewater treatment, the molecular sieve has the characteristics of strong selectivity, large capacity and simple regeneration for NH4 + , Pb 2+ , Cd 2+ and other cations, and is regarded as a new material for green deep treatment of wastewater.
[0003] Natural ore is rich in silicon and aluminum elements as well as K + , Na + and other cations, and can be used as raw material for synthesizing molecular sieve. Compared with chemical reagent raw material, it has the advantages of abundant reserves and low price, which can greatly reduce the preparation cost of molecular sieve. However, there are still some obstacles in preparing molecular sieve with natural ore as raw material. On the one hand, the silicon-aluminum ratio of natural ore usually deviates from the required range of target molecular sieve, and contains impurities such as Fe, Ca and Mg, so it is difficult to obtain molecular sieve with high crystallinity by direct hydrothermal crystallization. On the other hand, for the preparation process, the multi-factor synergistic effect of key parameters such as alkali dosage, silicon-aluminum ratio and hydrothermal synthesis temperature is not considered, resulting in low crystallinity of the product and unsatisfactory adsorption performance. For example, Chen Shuang used ZSM-5 molecular sieve adsorbent to treat ammonia-nitrogen wastewater, and the ammonia-nitrogen adsorption capacity was 3.54 mg / g; the ammonia-nitrogen adsorption capacity of X-type molecular sieve prepared by Zhi Yili was 1.6 mg / g, and the methylene blue adsorption capacity was 0.9 mg / g, and the adsorption performance of the molecular sieve still needs to be optimized.
[0004] Response Surface Methodology (RSM) is a powerful modeling and optimization tool that combines mathematics and statistics. It can establish a continuous response surface within a limited number of experiments, reveal the interaction of each factor, and determine the optimal combination of factor levels by quantitatively analyzing the relationship between experimental indicators and factors. It can effectively guide experimental design and process optimization, and is significantly better than traditional orthogonal experimental design. In the preparation of molecular sieves, RSM can be used to consider multiple reaction conditions to obtain the optimal molecular sieve preparation process parameters and efficiently prepare molecular sieves with high crystallinity.
[0005] Currently, there is no report on the application of response surface methodology to the process optimization of natural ore for preparing molecular sieves, and there is also a lack of application of natural ore-based molecular sieves in wastewater treatment. Therefore, developing a green preparation technology that uses natural ore as a silicon-aluminum source and optimizes the preparation process parameters through response surface methodology is of great significance for reducing the production cost of molecular sieves and achieving efficient and deep treatment of wastewater in coal chemical industry, petroleum chemical industry, smelting, and aquaculture. SUMMARY
[0006] The present application aims to provide a preparation method of natural mineral-based molecular sieves optimized based on response surface methodology and its application. The method uses natural ore as raw material, adopts alkali fusion-hydrothermal synthesis method, takes high crystallinity and high adsorption capacity as target, optimizes the particle size of ore powder, acid treatment pH, mass ratio, temperature, time, alkali fusion mass ratio, temperature, time, silicon-aluminum ratio, and hydrothermal synthesis temperature and time through response surface experiment (central composite design), so as to determine the optimal experimental conditions for preparing molecular sieves with high crystallinity and high adsorption capacity from natural ore, and provide basis for high-value utilization of natural ore. The process uses natural ore with rich reserves and low price as raw material to synthesize molecular sieves, thereby getting rid of the dependence on high-purity chemical reagents and significantly reducing the cost of raw materials. Before starting the preparation of molecular sieves, the ore powder is treated with acid to wash out impurity elements that are not conducive to the synthesis of molecular sieves. The molecular sieves can crystallize at low temperature during the preparation process, which is simple and safe to operate. The process significantly improves the quality of molecular sieves, and the prepared molecular sieves have the advantages of high crystallinity and high specific surface area, have high adsorption capacity for harmful substances in wastewater, and have excellent cyclic regeneration performance. The process provides a green, low-cost, and scalable wastewater adsorption technology route for coal chemical industry, petroleum chemical industry, smelting, and aquaculture, and promotes the high-value utilization of regional mineral solid waste and the resource utilization of liquid hazardous waste.
[0007] The preparation method of natural mineral-based molecular sieves optimized based on response surface methodology, wherein the molecular sieves are made of natural minerals as base material, and are prepared by acid treatment, alkali fusion, and hydrothermal synthesis. The specific operation is performed according to the following steps: a. Acid treatment: mix natural ore powder with dilute nitric acid solution, dilute hydrochloric acid solution or dilute sulfuric acid solution with pH=0.5-3 at a mass ratio of 0.5-10:100, stirring temperature 50-100 DEG C, stirring time 0.5-3h, to obtain ore powder; the ore powder is peridotite, basalt, andesite, diorite, granite, rhyolite or nepheline syenite, particle size 50-300um; b. Alkali fusion: mix the ore powder obtained in step a with alkali at a mass ratio of 100:50-200, put into a muffle furnace for high temperature melting, melting temperature 300-600 DEG C, melting time 2-5h; obtain silicate, then cool the silicate at room temperature, add water to dissolve the silicate, filter to obtain gel; the alkali used is sodium hydroxide, potassium hydroxide or mass ratio 3:1 of sodium hydroxide+potassium carbonate; c. Hydrothermal synthesis: adjust the silicon aluminum ratio of the gel obtained in step b to 0.5-5.0 by adding an aluminum source, and place it in a sealed reaction kettle for hydrothermal synthesis, temperature 30-210 DEG C, time 6-24h, after crystallization is completed, filter, wash with water, dry at temperature 120 DEG C for 12h to obtain natural mineral-based molecular sieve, the aluminum source is sodium metavanadate, sodium aluminate or aluminum nitrate nine water; The application discloses a preparation method of a natural mineral-based molecular sieve based on a response surface method optimization.
[0008] The application discloses a preparation method of a natural mineral-based molecular sieve based on a response surface method optimization.
[0009] The application discloses a preparation method of a natural mineral-based molecular sieve based on a response surface method optimization. + , Pb 2+ , Cd 2+ , Cr 3+ , Cu 2+ , methylene blue, methyl orange, congo red and phenol, and after adsorption is completed, the molecular sieve is placed in a salt solution of 1-2mol / L sodium chloride solution, potassium sulfate solution, sodium persulfate solution or potassium carbonate solution, stirring for 12-24h, and then filtering and drying at temperature 120 DEG C to complete regeneration of the molecular sieve.
[0010] Compared with the prior art, the application has the following advantages and beneficial effects: The application can comprehensively utilize multiple natural ores to prepare the molecular sieve, and the raw material cost is low and green and environment-friendly.
[0011] The application uses acid treatment of the ore powder to remove impurity elements such as Fe, Ca and Mg, which is beneficial to improving the purity of the molecular sieve. The application uses a response surface design to prepare the molecular sieve, optimizes the process parameters of the molecular sieve preparation, and prepares the molecular sieve with high crystallinity and high specific surface area. The method provided by the application is suitable for the preparation of A type, X type and A+X mixed type molecular sieves. BRIEF DESCRIPTION OF DRAWINGS
[0012] Figure 1 A process schematic diagram for preparing the molecular sieve of the application; Figure 2 X-ray diffraction diagrams of the materials in the embodiments 1-10 of the application; Figure 2 It can be seen that the molecular sieve prepared by the method is of A type, X type and A+X mixed type. Figure 3 A scanning electron microscope image of the molecular sieve sample of the embodiment 9 of the application; Figure 3 It can be observed that the micro-morphology of the molecular sieve obtained in the embodiment 9; Figure 4 A response stereographic distribution diagram and an isometric line diagram (X3=100) of Y=f(X1,X2) when the basalt ore is used as a raw material to prepare the molecular sieve of the application; Figure 4 The response surface diagram can directly observe the influence of the interaction of various factors on the relative crystallinity. Figure 5 A response stereographic distribution diagram and an isometric line diagram (X2=2.5) of Y=f(X1,X3) when the basalt ore is used as a raw material to prepare the molecular sieve of the application; Figure 5 The response surface diagram can directly observe the influence of the interaction of various factors on the relative crystallinity. Figure 6 A response stereographic distribution diagram and an isometric line diagram (X1=1) of Y=f(X2,X3) when the basalt ore is used as a raw material to prepare the molecular sieve of the application; the response surface diagram of the diagram can directly observe the influence of the interaction of various factors on the relative crystallinity. Figure 7 A NH4 + Before and after infrared spectrograms; by Figure 7 It can be seen that the molecular sieve adsorbs NH4 + After the infrared spectrogram, an obvious N-H peak appears. Figure 8 A schematic diagram of the harmful substance adsorption amount of the molecular sieve of the embodiments 1-10 of the application in the 200 mg / L wastewater of the polluting ion or molecule concentration; by Figure 8 It can be seen that the maximum adsorption amount of the harmful substance of the molecular sieve prepared in the embodiments 1-10 in the 200 mg / L wastewater of the polluting ion or molecule concentration ranges from 24 mg / g to 45 mg / g. DETAILED DESCRIPTION Embodiment 1
[0013] a, acid treatment: mix natural ore powder peridotite with particle size of 50 μm with dilute sulfuric acid solution with pH = 0.5 at mass ratio of 0.5:100, stirring temperature 50℃, stirring time 3h, to remove impurity elements, to obtain ore powder; b, alkali fusion: mix the peridotite ore powder obtained in step a with alkali sodium hydroxide at mass ratio of 100:200, put into muffle furnace for high temperature melting, melting temperature 300℃, melting time 5h; obtain silicate, then cool the silicate at room temperature, add water to dissolve the silicate, filter to obtain gel; c, hydrothermal synthesis: adjust the silicon aluminum ratio of the gel obtained in step b to 0.5 by supplementing aluminum source sodium metavanadate, place in a sealed reaction kettle for hydrothermal synthesis, temperature 30℃, time 24h, after crystallization is completed, filter, wash with water, dry at temperature 120℃ for 12h, to obtain natural mineral-based molecular sieve.
[0014] The molecular sieve prepared by the method is A-type molecular sieve, the crystallinity is about 16%, wherein the crystallinity (%) = (molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after preparation is completed, the molecular sieve is placed in 200 mg / L ammonium chloride solution for NH4 + adsorption, the adsorption capacity can reach 25 mg / g; after adsorption is completed, the molecular sieve is placed in 1 mol / L sodium chloride solution, stirred for 24h, filtered and dried at 120℃, to complete the regeneration of the molecular sieve. Example 2
[0015] a, acid treatment: grind andesite ore with a ball mill to obtain 300 μm ore powder, mix natural ore powder andesite with dilute hydrochloric acid solution with pH = 0.5-3 at mass ratio of 10:100, stirring temperature 100℃, stirring time 0.5h; b, alkali fusion: mix the andesite ore powder obtained in step a with alkali potassium hydroxide at mass ratio of 100:80, put into muffle furnace for high temperature melting, melting temperature 600℃, melting time 2h; cool the alkali fusion product at room temperature, add water to dissolve the silicate, filter to obtain gel, adjust the silicon aluminum ratio to 5.0 by supplementing aluminum source sodium aluminate; c, hydrothermal synthesis: place the gel obtained in step b in a sealed reaction kettle for hydrothermal synthesis, temperature 210℃, time 6h, after crystallization is completed, filter, wash with water, dry at temperature 120℃ for 12h, to obtain natural mineral-based molecular sieve.
[0016] The molecular sieve prepared by the method is an A+X mixed type molecular sieve, and the crystallinity is about 10%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area)×100%; after the preparation is completed, the molecular sieve is used as an adsorbent, and is placed in a 200 mg / L ammonium chloride solution to perform NH4 + adsorption, and the adsorption capacity can reach 38 mg / g; after the adsorption is completed, the molecular sieve is placed in a 2 mol / L potassium sulfate solution, is stirred for 12 h, is filtered, and is dried at 120°C, so that the regeneration of the molecular sieve is completed. Example 3
[0017] a, acid treatment: andesite ore is ground by a ball mill to obtain 50 μm ore powder, and is mixed with a dilute nitric acid solution with pH=3 at a mass ratio of 0.5:100, the stirring temperature is 100°C, and the stirring time is 3 h, so as to remove impurity elements; b, alkali fusion: the ore powder obtained in step a is mixed with sodium hydroxide+potassium carbonate (mass ratio 3:1) at a mass ratio of 100:50, and is fused in a muffle furnace at 600°C for 5 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 5 by supplementing an aluminum source of aluminum nitrate nonahydrate; c, hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 210°C, and the time is 24 h; after crystallization is completed, filtration, water washing, and drying at 120°C for 12 h are performed to obtain the molecular sieve.
[0018] The molecular sieve prepared by the method is an A+X mixed type molecular sieve, and the crystallinity is about 13%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area)×100%; after the preparation is completed, the molecular sieve is used as an adsorbent, and is placed in a 200 mg / L lead acetate solution to perform Pb 2+ adsorption, and the adsorption capacity can reach 30 mg / g; after the adsorption is completed, the molecular sieve is placed in a 1 mol / L sodium persulfate solution, is stirred for 24 h, is filtered, and is dried at 120°C, so that the regeneration of the molecular sieve is completed. Example 4
[0019] a, acid treatment: granite ore is ground by a ball mill to obtain 300 μm ore powder, and the natural ore granite ore powder is mixed with a dilute sulfuric acid solution with pH=0.5 at a mass ratio of 10:100, the stirring temperature is 50°C, and the stirring time is 0.5 h; b, alkali fusion: the granite ore powder obtained in step a is mixed with alkali potassium hydroxide at a mass ratio of 100:150, and is fused in a muffle furnace at a high temperature, the fusion temperature is 300°C, and the fusion time is 2 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 0.5 by supplementing an aluminum source of sodium aluminate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 30℃, the time is 24h, after the crystallization is completed, filtration, water washing, and drying at 120℃ for 12h are carried out, and a natural mineral-based molecular sieve is obtained.
[0020] The molecular sieve prepared by the method is an A+X mixed type molecular sieve, and the crystallinity is about 50%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L lead acetate solution for Pb 2+ adsorption, and the adsorption capacity can reach 29 mg / g; after the adsorption is completed, the molecular sieve is placed in a 2 mol / L potassium carbonate solution, is stirred for 12h, is filtered, and is dried at 120℃, and the regeneration of the molecular sieve is completed. Example 5
[0021] a. Acid treatment: the diabase ore is ground by a ball mill to obtain 100μm ore powder, and the natural ore diabase ore powder is mixed with a dilute hydrochloric acid solution with pH=3 at a mass ratio of 5:100, the stirring temperature is 70℃, and the stirring time is 3h; b. Alkali fusion: the diabase ore powder obtained in step a is mixed with alkali potassium hydroxide at a mass ratio of 100:50, is placed in a muffle furnace for high-temperature fusion, the fusion temperature is 600℃, and the fusion time is 3h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 5.0 by supplementing an aluminum source to sodium aluminate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 100℃, the time is 10h, after the crystallization is completed, filtration, water washing, and drying at 120℃ for 12h are carried out, and a natural mineral-based molecular sieve is obtained.
[0022] The molecular sieve prepared by the method is an A+X mixed type molecular sieve, and the crystallinity is about 25%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L cadmium chloride solution for Cd 2+ adsorption, and the adsorption capacity can reach 38 mg / g; after the adsorption is completed, the molecular sieve is placed in a 1 mol / L potassium sulfate solution, is stirred for 24h, is filtered, and is dried at 120℃, and the regeneration of the molecular sieve is completed. Example 6
[0023] a. Acid treatment: the basalt ore is ground by a ball mill to obtain 50μm ore powder, and the natural ore basalt ore powder is mixed with a dilute nitric acid solution with pH=0.5 at a mass ratio of 5:100, the stirring temperature is 80℃, and the stirring time is 0.5h; b. Alkali fusion: basalt ore powder obtained in step a is mixed with alkali potassium hydroxide in a mass ratio of 100:200, and is put into a muffle furnace for high-temperature melting, the melting temperature is 300 DEG C, and the melting time is 5 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 0.5 by adding an aluminum source of aluminum nitrate nonahydrate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 210 DEG C, and the time is 6 h, and after crystallization is completed, filtration, water washing, and drying at a temperature of 120 DEG C for 12 h are performed to obtain a natural mineral-based molecular sieve.
[0024] The molecular sieve prepared by the method is an A+X mixed type molecular sieve, and the crystallinity is about 45%, wherein the crystallinity (%) = (molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after preparation is completed, the molecular sieve is placed in a 200 mg / L cadmium chloride solution for Cd 2+ adsorption, and the adsorption capacity can reach 37 mg / g; after adsorption is completed, the molecular sieve is placed in a 2 mol / L potassium carbonate solution, stirred for 12 h, filtered, and dried at 120 DEG C to complete regeneration of the molecular sieve. Example 7
[0025] a. Acid treatment: andesite ore is ground by a ball mill to obtain 150 μm ore powder, and the natural ore andesite ore powder is mixed with a dilute sulfuric acid solution with a pH of 1.0 in a mass ratio of 10:100, the stirring temperature is 100 DEG C, and the stirring time is 1.0 h; b. Alkali fusion: andesite ore powder obtained in step a is mixed with sodium hydroxide+potassium carbonate in a mass ratio of 100:50, and the mixture is put into a muffle furnace for high-temperature melting, the melting temperature is 300 DEG C, and the melting time is 2 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 5.0 by adding an aluminum source of aluminum nitrate nonahydrate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 210 DEG C, and the time is 10 h, and after crystallization is completed, filtration, water washing, and drying at a temperature of 120 DEG C for 12 h are performed to obtain a natural mineral-based molecular sieve.
[0026] The molecular sieve prepared by the method is a mixed type A+X molecular sieve, and the crystallinity is about 40%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L methylene blue (MB) solution to adsorb methylene blue, and the adsorption capacity can reach 45 mg / g; after the adsorption is completed, the molecular sieve is placed in a 1.5 mol / L sodium chloride solution, is stirred for 24 h, is filtered, and is dried at 120 DEG C, so that the regeneration of the molecular sieve is completed. Example 8
[0027] a, acid treatment: the peridotite ore is ground by a ball mill to obtain 250 mu m ore powder, the natural ore peridotite ore powder is mixed with a dilute hydrochloric acid solution with pH = 2 at a mass ratio of 0.5:100, the stirring temperature is 50 DEG C, and the stirring time is 2 h; b, alkali fusion: the peridotite ore powder obtained in step a is mixed with alkali potassium hydroxide at a mass ratio of 100:200, is placed in a muffle furnace for high-temperature fusion, the fusion temperature is 600 DEG C, and the fusion time is 2 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, a gel is obtained after filtration, and the silicon aluminum ratio is adjusted to 5.0 by supplementing an aluminum source sodium aluminate; c, hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 100 DEG C, the time is 24 h, and after crystallization is completed, filtration, water washing, and drying at 120 DEG C for 12 h are performed, so that the natural mineral-based molecular sieve is obtained.
[0028] The molecular sieve prepared by the method is an X type molecular sieve, and the crystallinity is about 70%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L methylene blue solution to adsorb methylene blue, and the adsorption capacity can reach 24 mg / g; after the adsorption is completed, the molecular sieve is placed in a 2 mol / L sodium persulfate solution, is stirred for 16 h, is filtered, and is dried at 120 DEG C, so that the regeneration of the molecular sieve is completed. Example 9
[0029] a, acid treatment: the diorite ore is ground by a ball mill to obtain 300 mu m ore powder, the natural ore diorite ore powder is mixed with a dilute nitric acid solution with pH = 3 at a mass ratio of 8:100, the stirring temperature is 100 DEG C, and the stirring time is 1.5 h; b, alkali fusion: the diorite ore powder obtained in step a is mixed with alkali sodium hydroxide+potassium carbonate with a mass ratio of 3:1 at a mass ratio of 100:150, is placed in a muffle furnace for high-temperature fusion, the fusion temperature is 400 DEG C, and the fusion time is 3 h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, a gel is obtained after filtration, and the silicon aluminum ratio is adjusted to 3.0 by supplementing an aluminum source sodium metaborate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 120 DEG C, the time is 6h, after crystallization is completed, filtration, water washing, drying at 120 DEG C for 12h are carried out, and a natural mineral-based molecular sieve is obtained.
[0030] The molecular sieve prepared by the method is an X-type molecular sieve, and the crystallinity is about 80%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L phenol solution for phenol adsorption, and the adsorption capacity can reach 33 mg / g; after the adsorption is completed, the molecular sieve is placed in a 1.5 mol / L potassium sulfate solution, is stirred for 23h, is filtered, and is dried at 120 DEG C, and the regeneration of the molecular sieve is completed. Example 10
[0031] a. Acid treatment: the rhyolite ore is ground by a ball mill to obtain 50 mu m ore powder, and the natural ore rhyolite ore powder is mixed with a dilute sulfuric acid solution with pH=0.5 at a mass ratio of 8:100, the stirring temperature is 50 DEG C, and the stirring time is 2.5h; b. Alkali fusion: the rhyolite ore powder obtained in step a is mixed with alkali sodium hydroxide at a mass ratio of 100:50, is placed in a muffle furnace for high-temperature fusion, the fusion temperature is 300 DEG C, and the fusion time is 2h; the alkali fusion product is cooled at room temperature, water is added to dissolve the silicate, and a gel is obtained after filtration, and the silicon-aluminum ratio is adjusted to 4.0 by supplementing an aluminum source aluminum nitrate nonahydrate; c. Hydrothermal synthesis: the gel obtained in step b is placed in a sealed reaction kettle for hydrothermal synthesis, the temperature is 150 DEG C, the time is 12h, after crystallization is completed, filtration, water washing, drying at 120 DEG C for 12h are carried out, and a natural mineral-based molecular sieve is obtained.
[0032] The molecular sieve prepared by the method is an X-type molecular sieve, and the crystallinity is about 60%, wherein the crystallinity (%)=(molecular sieve sample main peak area / standard molecular sieve main peak area) x 100%; after the preparation is completed, the molecular sieve is used as an adsorbent, is placed in a 200 mg / L phenol solution for phenol adsorption, and the adsorption capacity can reach 35 mg / g; after the adsorption is completed, the molecular sieve is regenerated in a 1 mol / L potassium carbonate solution, is stirred for 13h, is filtered, and is dried at 120 DEG C, and the regeneration of the molecular sieve is completed.
[0033] The above only describes the preferred embodiments of the present application, and it should be pointed out that, for researchers in the technical field, improvements and refinements made without departing from the principles of the present application should also be considered within the protection scope of the present application.
Claims
1. A method for preparing natural mineral-based molecular sieves optimized based on response surface methodology, characterized in that: The molecular sieve is made from natural minerals as a base material, using acid treatment, alkali melting, and hydrothermal synthesis. The specific operation is carried out according to the following steps: a. Acid treatment: Natural ore powder is mixed with dilute nitric acid solution, dilute hydrochloric acid solution or dilute sulfuric acid solution with pH=0.5-3 at a mass ratio of 0.5-10:
100. The stirring temperature is 50-100℃ and the stirring time is 0.5-3h to obtain ore powder. The ore powder is peridotite, basalt, andesite, diorite, granite, rhyolite or nepheline syenite, and the particle size is 50-300μm. b. Alkali melting: Mix the mineral powder obtained in step a with alkali at a mass ratio of 100:50-200, and melt it in a muffle furnace at a high temperature of 300-600℃ for 2-5 hours to obtain aluminosilicate. Then, cool the aluminosilicate to room temperature, add water to dissolve it, and filter to obtain a gel. The alkali used is sodium hydroxide, potassium hydroxide, or sodium hydroxide + sodium carbonate at a mass ratio of 3:
1. c. Hydrothermal synthesis: The gel obtained in step b is adjusted to a silicon-to-aluminum ratio of 0.5-5.0 by supplementing with an aluminum source, and then placed in a sealed reactor for hydrothermal synthesis at a temperature of 30-210℃ for 6-24 hours. After crystallization, the gel is filtered, washed with water, and dried at 120℃ for 12 hours to obtain a natural mineral-based molecular sieve. The aluminum source is sodium aluminate, sodium aluminate, or aluminum nitrate nonahydrate.
2. The method for preparing natural mineral-based molecular sieves optimized based on response surface methodology as described in claim 1, characterized in that, This method is applicable to the preparation of type A molecular sieves, type X molecular sieves, and A+X mixed molecular sieves.
3. The method described in claim 1 provides the application of natural mineral-based molecular sieves in the preparation of wastewater adsorption.