CN101215003A - Preparation method of monolithic macroporous titanium oxide - Google Patents

Abstract

The invention discloses a method for preparing monolithic macroporous titanium oxide, which belongs to the preparation technology of monolithic porous inorganic oxides. The method includes the following processes: using styrene and divinylbenzene as monomers to prepare monolithic macroporous organic templates by reverse concentrated emulsion method; preparing TiO ₂ hydrosol with butyl titanate as precursor; filling TiO ₂ hydrosol into the monolithic macroporous organic template; the filled monolithic organic/inorganic composite is dried and calcined at 500°C to 600°C to remove the template to obtain monolithic macroporous titanium oxide. The advantage of the method is that the preparation process is simple and easy, and the prepared monolithic macroporous titanium oxide has micron-scale interconnected macropore channels with a pore diameter of 500 nm to 20 μm, and is suitable for use as a catalyst carrier, an adsorption material and a separation material.

Description

Preparation method of monolithic macroporous titanium oxide

technical field

The invention relates to a method for preparing monolithic macroporous titanium oxide, which belongs to the preparation technology of monolithic porous inorganic oxides.

Background technique

Integral macroporous oxides have attracted much attention due to their large pores ranging from hundreds of nanometers to tens of microns, high specific surface area, high damping performance, good thermal stability, and low dielectric constant. It is widely used in catalyst carrier, adsorption material, separation material, chromatographic packing, sound-absorbing and shock-absorbing material, optical fiber communication and other fields.

The preparation method of monolithic macroporous oxide is mainly the template method, and the template includes: surfactant, polymer porous ball, porous membrane, cellulose acetate permeable membrane, etc. Among them, C. Solans et al ^{[1, 2]} used phase inversion emulsion polymerization (PIT) to prepare polystyrene cellular materials, and prepared porous metal oxide materials using this material as a template. Compared with the traditional method, the polymer cellular material prepared by the PIT emulsification method has smaller pore size (<1um) and better pore size dispersion, so the prepared metal oxide porous material has a more regular structure and higher Compression ability. Du Zhongjie et al. ^[3] prepared polystyrene porous materials and polyacrylamide porous materials by super-concentrated emulsion method, and prepared a monolithic porous titanium oxide material with a pore size of several hundred nanometers and several micrometers using this material as a template. , and the pores are connected, and the pressure drop is small when the gas passes through. This material has a wider application prospect.

The template method is used to prepare monolithic macroporous materials, and the preparation steps mainly include: (1) preparation of monolithic organic template; (2) preparation of target product precursor; (3) filling target precursor into the template; (4) removing except organic template. Regarding the preparation of the target product precursor solution in step (2), the solution or alcohol sol of the target product is used for filling in previous literatures. On the one hand, this method has a large particle size after filling with a solution, resulting in a significant decrease in pore size; on the other hand, the alcohol sol has good wettability with the organic template, resulting in excessive filling, resulting in disconnected channels and reduced pore volume. .

references:

[1] SolansC.E squenaJ.A zemarN.Highly concentrated (gel)e mulsions, versatileReaction media, Current Opinion in Colloid and Interface Science, 2003(8), 156-163

[2] Jordi E.GSR Ravi S.Conxita S.Highly Concentrated W/O Emulsions Preparedby the PIT Method as Templates for Solid Foams, Langmuir, 2003(19), 2983-2988

[3] Du Zhongjie et al. Chemical Journal of Chinese Universities, 2002, 23(8): 1614～1618

Contents of the invention

The object of the present invention is to provide a preparation method of monolithic macroporous titanium oxide, which is simple and easy to implement, and the prepared monolithic macroporous titanium oxide has micron-scale interconnected macropore channels.

The present invention is achieved through the following technical solutions, a method for preparing monolithic macroporous titanium oxide, which is characterized in that it includes the following process:

(1) Preparation of template

Styrene and divinylbenzene (DVB) with a volume ratio of V (divinylbenzene)/V (styrene) = 1: 3.8 to 4.4 are used as monomers, and the mass added is 2% to 2% of the total monomer mass. 20% of the surfactant Span 80 and the initiator azobisisobutyronitrile (AIBN) whose mass is 0.1% to 2% of the total monomer mass are evenly mixed to form an oil phase. Adding deionized water to the oil phase under stirring, so that the volume fraction of the water phase is 75% to 90%, to obtain a reverse-phase thick emulsion. The concentrated emulsion is poured into a mold, sealed and polymerized at 50-65° C. for 24-48 hours, and dried at 60-90° C. for 24-48 hours to obtain an integral organic macroporous template.

(2) Preparation of TiO ₂ hydrosol

With butyl titanate as raw material, the molar ratio is n (butyl titanate)/n (absolute ethanol)/n (deionized water)/n (nitric acid)=1/9/3/0.3 ratio, the Add butyl titanate to absolute ethanol, then add deionized water and nitric acid, stir evenly, age at 20-25°C for 1 day, and then the volume ratio is v(butyl titanate)/v(deionized water) = 1/1 ratio, add deionized water again, and age at 20-25°C for 2-3 days to obtain TiO ₂ aqueous sol.

(3) Filling of TiO ₂ hydrosol

Fill the _TiO2 hydrosol obtained in step (2) into the monolithic organic macroporous template prepared in step (1), remove the excess sol on the template surface after filling, and place the monolithic organic/inorganic composite at 60-90 ° C Blast drying for 12-24 hours, repeat the filling and drying process 2-6 times.

(4) Removal of the template

The monolithic organic/inorganic composite obtained in step (3) is heated at a heating rate of 0.1-5° C./min to 500-700° C. and calcined for 1-8 hours to obtain monolithic macroporous titanium oxide.

The invention has the following advantages: the preparation process is simple and easy. The monolithic macroporous polystyrene template is prepared by the reverse-phase concentrated emulsion method, with cheap raw materials and simple operation. The precursor liquid uses TiO ₂ hydrosol, and the monolithic macroporous titanium oxide prepared has micron-scale interconnected macropore channels with a pore diameter of 1-50 μm, and mesoporous pores with a pore diameter of 2-50 nm exist on the pore wall. The monolithic macroporous titanium oxide with such a structure is suitable for use as a catalyst carrier, an adsorption material and a separation material. Integral organic templates with different shapes and sizes and pore sizes can be designed and prepared according to needs, so as to prepare integral macroporous oxides with different shapes and pore sizes.

Description of drawings

Fig. 1 is the SEM figure of the monolithic macroporous template that the embodiment of the present invention 1 makes

Fig. 2 is the SEM figure of monolithic macroporous _TiO2 that the embodiment of the present invention 1 makes

Detailed ways

Example 1

(1) Preparation of monolithic macroporous polystyrene template by inverse concentrated emulsion method

Styrene and divinylbenzene monomers were washed 4 times with an equal volume of 0.2 mol/L NaOH solution, and then washed 4 times with an equal volume of deionized water for later use. Accurately weigh 6 mL of washed styrene and 1.5 mL of divinylbenzene, and put them into a 100 mL three-necked bottle. Add 0.062g of initiator azobisisobutyronitrile and 0.54g of surfactant Span 80 therein, and stir to make it evenly mixed. Slowly add 33.9 mL of deionized water dropwise into the three-necked flask under stirring, and the dropping time is controlled at 60 min to form a reverse-phase thick emulsion. After continuing to stir for 30 minutes, the concentrated emulsion was moved into a mold, and placed in a constant temperature oven at 60°C for polymerization for 24 hours. The polymerized template was dried at 60° C. for 48 hours to obtain a monolithic macroporous polystyrene template.

(2) Preparation of TiO ₂ sol

Dissolve 20 mL of butyl titanate in 30.84 mL of absolute ethanol, add 3.173 mL of deionized water while stirring, the butyl titanate begins to hydrolyze, and then add 1.22 mL of nitric acid for peptization. After aging for 1 day at 25°C, add 20 mL of deionized water and age for 2 days at 25°C to obtain a transparent TiO ₂ sol.

(3) Filling of TiO ₂ sol

Fill the template prepared in step (1) with the TiO sol prepared in step ( ₂ ). After filling, the excess sol on the surface of the template was sucked off with filter paper, and then the monolithic organic/inorganic composite was dried at 70° C. for 12 hours. Repeat the filling and drying process 4 times.

(4) Roasting to remove the template

Add the organic/inorganic composite prepared in step (3) into a muffle furnace, and heat up to 550°C for 3 hours at a heating rate of 1°C/min to obtain monolithic macroporous TiO ₂ oxide with an average pore size of 2 μm.

Example 2

The preparation method and process were the same as in Example 1, except that the volume of deionized water added in step (1) was changed from 33.9ml to 24mL, and the average pore diameter of the prepared monolithic macroporous polystyrene template was 1.3 μm.

Example 3

The preparation method and process were the same as in Example 1, except that the volume of deionized water added in step (1) was changed from 33.9ml to 54mL, and the average pore diameter of the prepared monolithic macroporous polystyrene template was 4.2 μm.

Example 4

The preparation method and process were the same as in Example 1, except that the mass of the surfactant Span 80 added in step (1) was changed from 0.54 g to 0.108 g, and the average pore size of the prepared monolithic polystyrene template was 0.6 μm.

Example 5

The preparation method and process were the same as in Example 1, except that the quality of the surfactant Span 80 added in step (1) was changed from 0.54 g to 0.3 g, and the obtained _monolithic macroporous TiO had an average pore diameter of 2.6 μm.

Example 6

The preparation method and process were the same as in Example ₁ , except that the volume of butyl titanate added in step (2) was changed from 20ml to 15mL, and the obtained monolithic macroporous TiO had an average pore diameter of 0.6 μm.

Example 7

The preparation method and process were the same as in Example ₁ , except that the volume of butyl titanate added in step (2) was changed from 20ml to 25mL, and the obtained monolithic macroporous TiO had an average pore diameter of 3.8 μm.

Example 8

The preparation method and process were the same as in Example 1, except that the calcination temperature in step (4) was changed from 550°C to 500°C, and the average pore diameter of the obtained monolithic macroporous _TiO2 was 2.1 μm.

Example 9

The preparation method and process are the same as in Example 1, except that the calcination temperature in step (4) is changed from 550°C to 600°C, and the average pore diameter of the obtained monolithic macroporous _TiO2 is 3.4 μm.

Claims (1)

1. the preparation method of an integral macropore titanium oxide is characterized in that comprising following process:

(1) preparation of template

With divinylbenzene/volume of styrene ratio is that 1: 3.8～4.4 vinylbenzene and divinylbenzene are monomer, adding quality is the class of tensio-active agent department 80 of total monomer quality 2%～20%, and quality is the initiator Diisopropyl azodicarboxylate of total monomer quality 0.1%～2%, it behind the uniform mixing oil phase, under agitation in oil phase, add deionized water, the volume fraction that makes water is 75%～90%, obtain anti-phase concentrated emulsion, concentrated emulsion is poured in the mould, at 50～65 ℃ of sealing polymerization 24～48h, 60～90 ℃ of drying 24～48h obtain the organic macropore template of monolithic devices;

(2) TiO ₂The preparation of the water-sol

With the butyl (tetra) titanate is raw material, in butyl (tetra) titanate/dehydrated alcohol/deionized water/nitric acid mol ratio is 1/9/3/0.3 ratio, butyl (tetra) titanate is added in the dehydrated alcohol, add deionized water and nitric acid again, after stirring, at room temperature aging 1 day is that 1/1 ratio adds deionized water once more in butyl (tetra) titanate/deionized water volume ratio then, 20-25 ℃ was worn out 2～3 days, and obtained TiO ₂The water-sol;

(3) TiO ₂The filling of the water-sol

The TiO that filling step (2) makes in the organic macropore template of the monolithic devices that step (1) makes ₂The water-sol is filled the back and is removed the unnecessary colloidal sol of template surface, and this monolithic devices organic/inorganic composite at 60～90 ℃ of forced air drying 12～24h, is repeated filling and drying process 2～6 times;

(4) template removes

The monolithic devices organic/inorganic composite that step (3) is made is that 0.1～5 ℃/min is warming up to 500～700 ℃ of roasting 1～8h with temperature rise rate, obtains integral macropore titanium oxide.

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