阅读说明：本技术 一种硅铝分子筛的制备方法 (Preparation method of silicon-aluminum molecular sieve ) 是由 万俊杰 冯新 何锦强 刘志烽 林达武 谢晓仪 莫松斌 林雅静 陶海波 禤振星 温 于 2020-04-02 设计创作，主要内容包括：本发明公开了一种硅铝分子筛的制备方法,所述方法包括以下步骤：称量0.5g七水硫酸亚铁加入装有60mL蒸馏水的三口烧瓶中并加入60mL异丙醇；搅拌5min后,在通入氮气的情况下,缓慢滴加2mol/L的硼氢化钠并加至过量,5-10min后溶液颜色不改变；将正硅酸乙酯和硫酸铝溶解后以及模板剂混合加入三口烧瓶中,搅拌反应2h；然后快速滤去反应液,并用无水乙醇清洗多遍后放入真空干燥箱干燥后密封保存。(The invention discloses a preparation method of a silicon-aluminum molecular sieve, which comprises the following steps: weighing 0.5g of ferrous sulfate heptahydrate, adding the ferrous sulfate heptahydrate into a three-neck flask containing 60mL of distilled water, and adding 60mL of isopropanol; after stirring for 5min, slowly dropwise adding 2mol/L sodium borohydride under the condition of introducing nitrogen gas until the sodium borohydride is excessive, and keeping the color of the solution unchanged after 5-10 min; dissolving ethyl orthosilicate and aluminum sulfate, mixing with a template agent, adding into a three-neck flask, and stirring for reacting for 2 hours; then the reaction solution is filtered quickly, and the reaction solution is washed for a plurality of times by absolute ethyl alcohol and then is put into a vacuum drying oven for drying and then is sealed for storage.)

1. A method of making a silicoaluminophosphate molecular sieve, the method comprising the steps of:

s1 weighing 0.5g of ferrous sulfate heptahydrate, adding the ferrous sulfate heptahydrate into a three-neck flask containing 60mL of distilled water, and adding 60mL of isopropanol;

s2, stirring for 5min, slowly adding 2mol/L sodium borohydride dropwise and adding the sodium borohydride in an excessive amount under the condition of introducing nitrogen, wherein the color of the solution is not changed after 5-10 min;

s3, dissolving ethyl orthosilicate and aluminum sulfate, mixing with a template agent, adding into a three-neck flask, and stirring for reacting for 2 hours;

s4, quickly filtering out the reaction solution, washing with absolute ethyl alcohol for multiple times, drying in a vacuum drying oven, and sealing for storage.

2. The method of claim 1, wherein the ratio of ethyl orthosilicate to aluminum sulfate is 1:1, 2:1, 3:1, or 4:1, respectively.

3. The method of claim 2, wherein the ratio of ethyl orthosilicate to aluminum sulfate is 2: 1.

4. The method of claim 1, wherein the ratio of distilled water to absolute ethanol is 1:1, 1:2, or 2: 1.

5. The method of claim 4, wherein the ratio of distilled water to absolute ethanol is 1: 1.

6. The method of claim 1, wherein the amount of sodium hydroxide in the sodium borohydride is 1, 2, 4, 6, 8, or 10 mL.

7. The method of claim 6, wherein the amount of sodium hydroxide is 10 mL.

8. The method of claim 1, wherein the templating agent is dodecylamine, isopropanolamine or tetramethylethylenediamine, wherein the amount of dodecylamine added is 1mL, the amount of isopropanolamine added is 1.5mL, and the amount of tetramethylethylenediamine added is 6 mL.

Technical Field

The invention relates to the technical field of molecular sieve preparation, in particular to a preparation method of a silicon-aluminum molecular sieve.

Background

Nanometer zero-valent iron (nZVI) is widely used for removing various environmental pollutants such as heavy metals (cadmium, arsenic, cobalt, zinc, chromium, copper, lead, uranium and the like), organic matters (mainly halogenated organic matters, dyes and pesticides) and inorganic matters (nitrate, bromate, high aluminate and the like) due to small particle size, large specific surface area, good adsorbability and strong reducibility.

However, in practical application, the following problems still exist: (1) physical and chemical properties: easy oxidation and easy particle agglomeration (poor dispersibility), resulting in a decrease in reactivity. (2) In the application aspect: the selectivity is poor, because the nZVI can remove various pollutants in an adsorption and reduction mode, and the adsorption and reduction degradation functions of the nZVI are applicable to all pollutants and have no specific selectivity, the nZVI is limited when being used for treating pollutants difficult to degrade, and the application range of the nZVI is limited due to huge waste caused by overlarge consumption.

Common methods for changing the surface function of the nano material include (1) coating nZVI with organic matters, which proves that the dispersion and the reduction effect of the nZVI are greatly improved. (2) The development of bimetallic nZVI can effectively improve the reduction efficiency of nZVI. (3) The nZVI is loaded on a specific carrier, so that the dispersity of the nZVI is improved. (4) The nZVI is coated by the mesoporous material, so that the dispersibility and the selective adsorption to target pollutants are improved.

With the innovation of adsorbents and the development of adsorption processes, adsorption is an important separation means, and is often used for substance recovery and removal and sensor preparation. Common adsorbents include activated carbon, molecular sieves, and the like. Because of its high specific surface area and large number of micropores with uniform diameter, it can selectively adsorb the substances with different molecular diameters.

The molecular sieve is a silicon-oxygen tetrahedron (SiO)₄)^4-]And alundum tetrahedron [ (AIO)₄)^5-]Is a primary structural unit and is arranged according to a certain rule to form the crystal framework material with a regular pore channel structure. The molecular sieve has large specific surface area, uniform aperture and good shape-selective catalysis, and is widely applied to the fields of chemical catalysis, adsorption separation and the like. Research shows that the molecular sieve is proved to be an effective method for endowing the molecular sieve with selective adsorption function by multi-element engineering on the nanometer scale.

The Zhou soldier introduces a growth induced corrosion method to prepare mesoporous organosilicon nano-material with a hollow structure, and mesoporous organosilicon hollow nanospheres with different shell thicknesses, particle sizes and organic functional group modifications can be prepared by changing reaction conditions. Meanwhile, functional nano particles with different frameworks are integrated with the porous molecular sieve, so that the porous functional selective material with different structures, types, functions and applications can be obtained. Wang et Al supported Al on mesoporous molecular sieve SBA-5 by vacuum self-assembly method, and changed the Si/Al ratio to obtain Al-SBA-5 mesoporous molecular sieve with high specific surface area and narrow particle size distribution. The silicon-aluminum ratio in the molecular sieve is changed, so that the pore canal and the space structure of the molecular sieve can be modified, the hydrophilic and hydrophobic performance, the pore wall structure and the surface area of the molecular sieve are improved, the molecular sieve has a special space structure, the selectivity of the molecular sieve is different, and the molecular sieve has a specific function. Zhang ze Zheng Zhong, etc. uses the hydrothermal method to graft the phenyl and the methyl into the molecular sieve, because the methyl and the phenyl both belong to hydrophobic groups, the hydrophobicity of the molecular sieve surface is improved, the above research mainly focuses on the research of the influence of the change of the synthesis conditions on the aperture and the function of the molecular sieve.

Disclosure of Invention

The invention discusses a preparation method of a silicon-aluminum molecular sieve, which improves the performance of the molecular sieve by optimizing preparation conditions such as silicon-aluminum ratio, type and dosage of a template agent, alkalinity, preparation time, water/alcohol ratio and the like.

Furthermore, the invention focuses on the study of preparing core-shell structures with different forms by using nano-iron as a core and using mesoporous substances generated by hydrolysis of silicon-aluminum oxides as a coating layer. Because the surface of the silicon oxide contains a large number of hydrophilic group hydroxyl groups, and the surface of the aluminum oxide has hydrophobic property, the mesoporous core-shell material suitable for selectively adsorbing different types of molecules and ions is searched by changing the content ratio of silicon to aluminum, and mesoporous channels suitable for passing different types of molecules and ions are designed by utilizing the difference of the space structures of the silicon oxide and the aluminum oxide. The selective adsorption and transmission of the mesoporous material to molecules and ions of different types and sizes are realized by accurately controlling the size of a pore passage of the outer coating layer of the nano iron and selectively regulating and controlling the hydrophilicity and hydrophobicity of the silicon oxide and the aluminum oxide. The invention can be applied to the selective transmission and degradation of specific components, can also be used for preparing selective permeation membranes and selective determination membranes, and has great application value.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method of making a silicoaluminophosphate molecular sieve, the method comprising the steps of:

s1 weighing 0.5g of ferrous sulfate heptahydrate, adding the ferrous sulfate heptahydrate into a three-neck flask containing 60mL of distilled water, and adding 60mL of isopropanol;

s2, stirring for 5min, slowly adding 2mol/L sodium borohydride dropwise and adding the sodium borohydride in an excessive amount under the condition of introducing nitrogen, wherein the color of the solution is not changed after 5-10 min;

s3, dissolving ethyl orthosilicate and aluminum sulfate, mixing with a template agent, adding into a three-neck flask, and stirring for reacting for 2 hours;

s4, quickly filtering out the reaction solution, washing with absolute ethyl alcohol for multiple times, drying in a vacuum drying oven, and sealing for storage.

Preferably, the ratio of ethyl orthosilicate to aluminum sulfate is 1:1, 2:1, 3:1 or 4:1, respectively.

Preferably, the ratio of ethyl orthosilicate to aluminum sulfate is 2: 1.

Preferably, the ratio of the distilled water to the absolute ethyl alcohol is 1:1, 1:2 or 2:1 respectively.

Preferably, the ratio of distilled water to absolute ethanol is 1: 1.

Preferably, the amount of sodium hydroxide in the sodium borohydride is 1, 2, 4, 6, 8 or 10 mL.

Preferably, the amount of sodium hydroxide is 10 mL.

Preferably, the template agent is dodecylamine, isopropanolamine or tetramethylethylenediamine, wherein the dosage of dodecylamine added is 1mL, the dosage of isopropanolamine added is 1.5mL, and the dosage of tetramethylethylenediamine added is 6 mL.

Drawings

FIG. 1 shows the preparation of molecular sieves with different Si/Al ratios according to the present invention, in which the stirring time is related to Cr⁶⁺Removing the influence test chart;

FIG. 2 shows the volume ratio of different hydroalcoholic solutions to Cr according to the present invention⁶⁺Removing the influence test chart;

FIG. 3 shows different amounts of NaOH added versus Cr according to the present invention⁶⁺Removing the influence test chart;

FIG. 4 shows the different amounts of dodecylamine added versus Cr in accordance with the present invention⁶⁺Removing the influence test chart;

FIG. 5 shows different amounts of isopropanolamine added to Cr⁶⁺Removing the influence test chart;

FIG. 6 shows different amounts of tetramethylethylenediamine added to Cr⁶⁺The removed influence is tested.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, and it should be noted that the following examples are provided to illustrate the detailed embodiments and specific operations based on the technical solutions of the present invention, but the scope of the present invention is not limited to the examples.

The invention relates to a preparation method of a silicon-aluminum molecular sieve, which comprises the following steps:

s1 weighing 0.5g of ferrous sulfate heptahydrate, adding the ferrous sulfate heptahydrate into a three-neck flask containing 60mL of distilled water, and adding 60mL of isopropanol;

s2, stirring for 5min, slowly adding 2mol/L sodium borohydride dropwise and adding the sodium borohydride in an excessive amount under the condition of introducing nitrogen, wherein the color of the solution is not changed after 5-10 min;

s3, dissolving ethyl orthosilicate and aluminum sulfate, mixing with a template agent, adding into a three-neck flask, and stirring for reacting for 2 hours;

s4, quickly filtering out the reaction solution, washing with absolute ethyl alcohol for multiple times, drying in a vacuum drying oven, and sealing for storage.

Preferably, the ratio of ethyl orthosilicate to aluminum sulfate is 1:1, 2:1, 3:1 or 4:1, respectively.

Preferably, the ratio of ethyl orthosilicate to aluminum sulfate is 2: 1.

Preferably, the ratio of the distilled water to the absolute ethyl alcohol is 1:1, 1:2 or 2:1 respectively.

Preferably, the ratio of distilled water to absolute ethanol is 1: 1.

Preferably, the amount of sodium hydroxide in the sodium borohydride is 1, 2, 4, 6, 8 or 10 mL.

Preferably, the amount of sodium hydroxide is 10 mL.

Preferably, the template agent is dodecylamine, isopropanolamine or tetramethylethylenediamine, wherein the dosage of dodecylamine added is 1mL, the dosage of isopropanolamine added is 1.5mL, and the dosage of tetramethylethylenediamine added is 6 mL.