Method for synthesizing bimodal silicon-aluminum mesoporous material

Abstract

The invention relates to a method for synthesizing a bimodal silicon-aluminum mesoporous material. The method comprises that: pulverized coal ash / black liquid for papermaking or strong alkali is used as a raw material; firstly, the raw material is evenly mixed in a solution, dried and roasted in a muffle furnace; a roasted product is dissolved by water or acid; an insoluble substance is filtered and removed; and the solution is condensed to obtain a raw material solution for synthesizing the mesoporous material. A surfactant, namely a triblock copolymer (P123) of three block polymers of polyoxyethylene, polyoxypropylene and polyoxyethylene used as a structure guiding agent is dissolved in water, and the mixture is stirred at a constant temperature for more than 1 hour, and slowly dripped with the raw material solution; after the dripping, hydrochloric acid is added into the solution, continuously stirred for more than 24 hours, crystallized at the temperature of 100 DEG C, cooled and filtered to obtain a coarse product; after the coarse product is naturally dried at room temperature, the coarse product can be roasted at the temperature of 550 DEG C or extracted by ethanol to remove the structure guiding agent; and after the coarse product is dried, the mesoporous material of which aperture is in bimodal distribution, namely bimodal SBA-15 is obtained. The mesoporous material contains two kinds of mesopores, wherein the small mesopore is within the range between 3 and 4 nm; the large mesopore is within the range between 5 and 7 nm; an SEM image also shows two different pores; BET nitrogen adsorption proves that the specific surface area of the pore is between 500 and 700m<2> / g; and the size of the pore is between 0.4 and 0.6 cm<3> / g.

Description

(1) Technical field [0001] The present invention relates to a method for synthesizing mesoporous materials, in particular to a method for synthesizing bimodal mesoporous materials using fly ash / coal gangue and papermaking black liquor or fly ash / coal gangue and alkali as raw materials; bimodal is It means that there are two high-intensity peaks at different pore sizes on the pore size distribution curve. (2) Background technology [0002] Inorganic porous materials, due to their large specific surface area and adsorption capacity, have a wide range of applications in the fields of adsorption, separation, and catalysis. According to the definition of the International Union of Pure and Applied Chemistry (IUPAC), porous materials can be divided into the following three types according to the pore size: Microporous, Mesoporous and Macroporous materials. The pore diameter of inorganic microporous materials is generally <2nm, including wollastonite, activated carbon, zeolite,...

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Problems solved by technology

[0006] However, the raw materials for the synthesis of SBA series mesoporous materials and the structure-directing agent are still expensive. Although the structure-directing agent can be recycled, which can reduce its synthesis cost to a certain extent, the cost of organosilane as a raw material is difficult to reduce

Some people also use inorganic raw material sodium metasilicate (Na 2 SiO 3 ·H 2 O) The mesoporous material FDU-7 (Wang Limin, 2002: ZL 02 1 36298.x) with a structure close to SBA-15 was successfully synthesized from a silicon source, but the mesoporous material has a single pore size distribution structure and only contains a single component Silicon dioxide; the patent application with the patent number ZL 03 1 11246.3 also uses sodium metasilicate and sodium metaaluminate as raw materials, but the synthesized mesoporous material also has a single pore size distribution structure; the patent number is ZL 2004 1 0066437.1 Although a variety of inorganic silicon and aluminum raw materials were used in the patent application, the pore size of the synthesized material was small, and it also had a single pore size distribution.

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