阅读说明：本技术 一种有序氧化铝材料的制备方法 (Preparation method of ordered alumina material ) 是由 申志兵 梁生荣 张君涛 刘峰 钟汉斌 唐瑞源 杨康 于 2020-08-12 设计创作，主要内容包括：本发明属于无机材料制备技术领域,涉及一种孔径大小可调控且孔径分布范围窄的有序氧化铝材料的制备方法,包括以下步骤：将无机铝盐与有机模板剂溶于去离子水及低碳醇的混合溶剂中,得到前驱体溶胶浆液,然后将助凝剂加入溶胶浆液中,生成前驱体凝胶,再将凝胶静置老化后过滤,滤饼洗涤后干燥,所得固体在550℃下焙烧4h,即得。本发明提供的有序氧化铝材料的制备方法,以廉价无机铝盐为铝源,成本低廉,操作简便,所得有序氧化铝粉体的平均孔径在5-80nm范围内可调变,孔径分布狭窄,并同时具有较高的比表面积。(The invention belongs to the technical field of inorganic material preparation, and relates to a preparation method of an ordered alumina material with adjustable aperture size and narrow aperture distribution range, which comprises the following steps: dissolving inorganic aluminum salt and an organic template agent in a mixed solvent of deionized water and low-carbon alcohol to obtain precursor sol slurry, adding a coagulant aid into the sol slurry to generate precursor gel, standing and aging the gel, filtering, washing a filter cake, drying, and roasting the obtained solid at 550 ℃ for 4 hours to obtain the catalyst. The preparation method of the ordered alumina material provided by the invention takes cheap inorganic aluminum salt as an aluminum source, has low cost and simple and convenient operation, and the average pore diameter of the obtained ordered alumina powder is adjustable within the range of 5-80nm, has narrow pore diameter distribution and higher specific surface area.)

1. The preparation method of the ordered alumina material is characterized by comprising the following steps of:

s1, dissolving inorganic aluminum salt and an organic template agent in the mixed solvent to obtain precursor glue solution;

wherein the mass ratio of the organic template to the inorganic aluminum salt is 0.1-0.5: 1;

the mixed solvent is formed by mixing low-carbon alcohol and deionized water according to the mass ratio of 10-95: 5-90;

the mass ratio of the mixed solvent to the inorganic aluminum salt is 1-10: 1;

s2, adding a gelling agent into the precursor gel slurry, and fully stirring to obtain precursor gel;

s3, standing and aging the precursor gel, filtering, and washing the obtained filter cake with deionized water and ethanol in sequence to obtain a pseudo-boehmite filter cake;

s4, drying the pseudo-boehmite filter cake, heating to 400-600 ℃ at the heating rate of 0.5-5 ℃/min, and roasting for 2-6 h to obtain the ordered alumina powder.

2. The method for preparing the ordered alumina material as claimed in claim 1, wherein the mass ratio of the lower alcohol to the deionized water is 20-70:30-80, and the mass ratio of the mixed solvent to the inorganic aluminum salt is 3-5: 1.

3. The method for preparing an ordered alumina material according to claim 1 or 2, wherein the lower alcohol is any one of methanol, ethanol, n-propanol, isopropanol or ethylene glycol.

4. The method for preparing an ordered alumina material according to claim 1, wherein the inorganic aluminum salt is any one of aluminum chloride, aluminum sulfate or aluminum nitrate.

5. The method for preparing an ordered alumina material according to claim 1 or 4, wherein the organic template is any one of polyethylene glycol, di-n-propylamine, diisopropylamine, di-n-butylamine, hexadecylammonium bromide or a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

6. The method for preparing an ordered alumina material as claimed in claim 1, wherein the coagulant aid is ethylene oxide or propylene oxide, and the mass ratio of the coagulant aid to the inorganic aluminum salt is 1-8: 1.

7. The method for preparing an ordered alumina material as claimed in claim 6, wherein the mass ratio of the coagulant aid to the inorganic aluminum salt is 2-4: 1.

8. The method for preparing the ordered alumina material as claimed in claim 1, wherein the standing aging is aging at a constant temperature of 30-80 ℃ for 12-48h in S3.

9. The method for preparing an ordered alumina material as claimed in claim 1, wherein in S4, the drying is performed at 70-130 ℃ for 2-8 h.

Technical Field

The invention belongs to the technical field of inorganic material preparation, and relates to a preparation method of an ordered alumina material with adjustable pore size and narrow pore size distribution range.

Background

Alumina is an inorganic oxide with very wide industrial application, can be used for preparing mesoporous and macroporous materials with the pore diameter larger than 2nm at present by a manual synthesis mode, is often used as a catalyst or a catalyst carrier to be applied to the fields of processing and product refining of fossil energy such as coal, petroleum and the like and photocatalysis, and can also be applied to the aspects of industrial adsorbents, chromatographic column filling materials and the like. In order to further improve the catalytic activity and the adsorption performance of the catalyst, different requirements are required for alumina materials with different pore diameters and narrow pore diameter distribution on different occasions, for example, a catalyst carrier used in the process of light oil product hydrofining mainly adopts mesopores with smaller pore diameters, and a heavy oil catalyst carrier mainly adopts larger mesopore and macropore alumina materials for ensuring the diffusion of macromolecular compounds and reducing carbon deposition. For the former, mesoporous alumina with smaller pore diameter is needed, and if the pore diameter distribution is wider, the mechanical strength of the material and the conversion rate and selectivity of reaction products can be reduced; the latter macroporous alumina material contains more small pore diameters, which are not beneficial to molecular diffusion on one hand, and are easy to cause pore channel blockage to cause catalyst deactivation on the other hand. Therefore, the preparation of alumina materials with different pore sizes and concentrated pore size distribution has been one of the key points of research.

At present, the aim of adjusting the pore diameter can be achieved by selecting different templates and aluminum sources in the preparation process, but the method seriously influences the purity and the orderliness of the alumina. At present, there are many methods in the field of preparing alumina materials with different pore diameters, for example, CN 101412527B discloses a preparation method capable of effectively controlling precursors to aggregate in different forms to generate different mesoporous structures by changing limited reaction conditions, and the specific preparation method is to strictly control the preparation conditions and preparation procedures, and to adjust the pore size of alumina by changing the types of surfactants, the molar ratio of solvents to surfactants, and the like; CN102173442B also discloses a method for preparing alumina with adjustable pore size, which uses different types of dispersants and changes the usage amount of the dispersants to adjust the pore size of alumina. The methods have the problems of more rigorous control of preparation conditions, narrow controllable range of pore diameters, wide distribution range of pore diameters, higher industrial cost and the like.

Disclosure of Invention

The invention provides a preparation method of an ordered alumina material, which takes cheap inorganic aluminum salt as an aluminum source, has low cost and simple and convenient operation, and the average pore diameter of the obtained ordered alumina powder is adjustable within the range of 5-80nm, has narrow pore diameter distribution and higher specific surface area.

The preparation method of the ordered alumina material provided by the invention comprises the following steps:

s1, dissolving inorganic aluminum salt and an organic template agent in the mixed solvent to obtain precursor glue solution;

wherein the mass ratio of the organic template to the inorganic aluminum salt is 0.1-0.5: 1;

the mixed solvent is formed by mixing low-carbon alcohol and deionized water according to the mass ratio of 10-95: 5-90;

the mass ratio of the mixed solvent to the inorganic aluminum salt is 1-10: 1;

s2, adding a gelling agent into the precursor gel slurry, and fully stirring to obtain precursor gel;

s3, standing and aging the precursor gel, filtering, and washing the obtained filter cake with deionized water and ethanol in sequence to obtain a pseudo-boehmite filter cake;

s4, drying the pseudo-boehmite filter cake, heating to 400-600 ℃ at the heating rate of 0.5-5 ℃/min, and roasting for 2-6 h to obtain the ordered alumina powder.

Preferably, the mass ratio of the low-carbon alcohol to the deionized water is 20-70:30-80, and the mass ratio of the mixed solvent to the inorganic aluminum salt is 3-5: 1.

Preferably, the lower alcohol is any one of methanol, ethanol, n-propanol, isopropanol or ethylene glycol.

Preferably, the inorganic aluminum salt is any one of aluminum chloride, aluminum sulfate or aluminum nitrate.

Preferably, the organic template is any one of polyethylene glycol, di-n-propylamine, diisopropylamine, di-n-butylamine, hexadecylammonium bromide or a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer.

Preferably, the coagulant aid is ethylene oxide or propylene oxide, and the mass ratio of the coagulant aid to the inorganic aluminum salt is 1-8: 1.

Further preferably, the mass ratio of the coagulant aid to the inorganic aluminum salt is 2-4: 1.

Preferably, in S3, the standing aging is aging at 30-80 ℃ for 12-48 h.

Preferably, in S4, the drying is at 70 ℃ to 130 ℃ for 2h to 8 h.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, by changing the solvent ratio, the hydrolysis rate of aluminum ions in inorganic aluminum salt of a precursor is effectively controlled to form macromolecular aluminum sol with different structural forms, and pseudo-boehmite intermediates with different molecular arrangements and forms are formed under the self-assembly and structure-oriented actions of the precursor and a template, so that the pore size of alumina is controlled and regulated, the pore size of the alumina material can be regulated within the range of 5-80nm as required, the pore size distribution is narrow, and the alumina material has a higher specific surface area;

2. the method takes cheap inorganic aluminum salt as an aluminum source, has low cost and is simple and convenient to operate; and the synthetic route is simple, the reaction condition is mild, and the industrialization is easy to realize.

Description of the figures

FIG. 1 is an XRD spectrum of an ordered mesoporous alumina powder; wherein 2, 3, 4 and 5 represent example 2, example 3, example 4 and example 5, respectively;

FIG. 2 is a graph of pore size distribution of an ordered mesoporous alumina powder; here, 2, 3, 4 and 5 represent example 2, example 3, example 4 and example 5, respectively.

Detailed Description

Several embodiments of the present invention are described in detail below, but it should be understood that the scope of the present invention is not limited to the embodiments.