CN103922347A - Continuous silica aggregate lipsome material and preparation method thereof - Google Patents

Abstract

The invention discloses a silicon dioxide continuous aggregate vesicle material and a preparation method thereof, which belong to the technical field of porous materials. The morphology of the material of the present invention is a continuous aggregate double-shell hollow bubble, with a size of 20-100nm and a bulk density of 0.01-0.10g/cm ³ ; the pore size distribution is multi-level pores, divided into 2-4nm interwall Pores and 20-40nm vesicle pores, the thickness of the pore wall is 4-6nm; the specific surface area is 600-1100m ² /g. The preparation method comprises dissolving SDS and CTAB successively in the ammonia water-water mixed solution, adding TEOS to heat, hydrolyze and condense the product under alkaline conditions. The invention has mild reaction conditions, simple required equipment, easy operation, short reaction time and extremely high efficiency. After scaling up the reactants in equal proportions, a pilot test was carried out in a 50L reactor, and the obtained product had no significant difference from the small-batch reaction.

Description

A kind of silica continuous aggregate vesicle material and its preparation method

technical field

The invention belongs to the technical field of porous materials, and in particular relates to a vesicle material of continuous aggregates of silicon dioxide, and in an alkaline system, through the comprehensive action of anion and cation surfactants, a large amount of said A method for continuous aggregate-like silica vesicle materials.

Background technique

Due to its high specific surface area, pore volume, adjustable pore size and good biocompatibility, mesoporous silica has aroused extensive interest of researchers, and has achieved a large number of applications in adsorption, catalyst and drug carrier. results. In the application of mesoporous silica, its morphology is a very important factor, such as rod, spherical, fibrous, vesicle and so on. Vesicular silica has high mechanical strength and good hydrothermal stability in the mesoporous silica material system, and it has a more significant role in practical application in adsorption or drug controlled release. Our research group has prepared mesoporous silica materials with ordered pores through a very dilute alkaline system. Hexadecyltrimethylammonium bromide is used as a surfactant and ethyl orthosilicate is used as a silicon source. It is formed by hydrolysis and condensation of sodium oxide or ammonia water alkaline system.

Patent CN1730392A discloses a method for preparing large-volume silica vesicles, using amphiphilic surfactant dissolved in buffer as a template agent, methyl orthosilicate or ethyl orthosilicate as a silicon source, and successively undergoing normal temperature Silica vesicles and foam materials with adjustable pore size and size can be obtained after standing process and high temperature hydrothermal process, and calcining to remove the template agent. The pore diameter is 10-200nm, and the pore volume is 1-3cm ³ /g.

Patent 101289189A discloses a method for preparing silica vesicles with controllable shape, size, and wall thickness. Two amphiphilic surfactants are mixed and dissolved in buffer as templates, and methyl orthosilicate and ethyl orthosilicate are used as templates. The silicon source has undergone a static process and a high-temperature hydrothermal process successively, and after calcining to remove the template agent, silica vesicles with rich morphology and adjustable wall thickness are obtained. The shape of the material is hollow spherical or hollow tubular, the pore size is 25-100 nm, and the wall thickness is adjustable from 5-25 nm.

Patent 103011182A discloses a mesoporous silica vesicle material that uses anion-cation mixed surfactants CTAB and SDS as templates, TEOS as a silicon source, undergoes stirring at room temperature and high-temperature hydrothermal process, and calcines to remove the template. The morphology is hollow vesicles, the average size is 200-400nm, the wall thickness is about 10nm, and nano-silica particles with a size of 20-40nm are deposited on the surface.

Contents of the invention

The purpose of the present invention is to provide a silica continuous aggregate vesicle material.

The purpose of the present invention is also to provide a method for preparing the above-mentioned silica continuous aggregate vesicle material.

Technical scheme of the present invention is as follows:

A continuous aggregate vesicle material of silica, whose appearance is a continuous aggregate double-shell hollow bubble, with a size of 20-100nm and a bulk density of 0.01-0.10g/cm ³ ; the pore size distribution is multi-level pores, Divided into interwall pores of 2-4nm and vesicular pores of 20-40nm, the wall thickness of the pores is 4-6nm; the specific surface area is 600-1100m ² /g.

A method for preparing the above-mentioned silica continuous aggregate vesicle material in large quantities, comprising the following steps:

(1) SDS: CTAB: TEOS: H ₂ O: NH ₄ OH is 1: (1~2.33): (16~20): 6143.9:557.3 Weigh sodium dodecylsulfonate SDS, cetyl Alkyltrimethylammonium bromide CTAB: ethyl orthosilicate TEOS, H ₂ O and 25wt% ammonia water;

(2) Dissolve SDS in the mixture of deionized water and ammonia water under stirring at 68°C, add CTAB after clarification, and quickly add TEOS after the solution is clarified again, continue to react at this temperature for 2 hours, and filter the reactant with suction , followed by washing with deionized water and ethanol and drying at 60°C;

(3) After drying, use a muffle furnace to calcine at 550°C for 4 hours to remove the template agents SDS and CTAB to obtain the target product.

Preferably, in step (1 ₎ , sodium dodecylsulfonate SDS, _hexadecyltri Methyl ammonium bromide CTAB: ethyl orthosilicate TEOS, H ₂ O and 25wt% ammonia water.

The stirring rate in step (2) is 300rpm.

The mesoporous silicon dioxide vesicles prepared by the method of the present invention use mixed anion and cation surfactants as templates, and ethyl orthosilicate as a silicon source, and are synthesized by hydrolysis and condensation under alkaline heating conditions. The prepared product is a continuous vesicle with a size of 20-100nm. The thickness of the pore wall is 4-6nm. It is 600-1100m ² /g, and the product has good uniformity.

The beneficial effects of the present invention are: the mesoporous silica vesicles prepared by the present invention have multi-level pore distribution, good uniformity, large specific surface area, and have high prospects in the application of adsorption and drug carriers. The preparation method of the invention has simple experimental conditions, mildness and extremely high efficiency, and the reaction process only needs 2 hours. Due to the simplicity of the process, the inventive method can be easily applied to large-scale production. Tests have shown that there is no significant difference between the product obtained in the pilot test and the small-scale experiment when the formula is enlarged to 55 times, indicating the stability of the inventive method. . The difference between the preparation method of the present invention and the prior art lies in that it is based on the technology of synthesizing mesoporous silica under alkaline conditions. By adding anionic surfactants, it is only prepared through a short-term hydrothermal process under mild conditions. Double-shell continuous aggregates of order pores in vesicular mesoporous silica.

Description of drawings

Fig. 1 is a transmission electron microscope image of mesoporous silica vesicles prepared in Example 1 of the present invention.

Fig. 2 is the transmission electron microscope (A) and scanning electron microscope (B) photographs of the mesoporous silica vesicles prepared in Example 2 of the present invention.

Fig. 3 is the small-angle X-ray diffraction pattern (A) and the nitrogen adsorption-desorption curve (B) of the mesoporous silica vesicles prepared in Example 2 of the present invention.

Fig. 4 is a transmission electron microscope image of the mesoporous silica vesicles prepared in Example 3 of the present invention.

Fig. 5 is a transmission electron microscope image of the mesoporous silica vesicles prepared in Example 4 of the present invention.

Detailed ways

Below in conjunction with embodiment further illustrate the present invention.

Embodiment one

Dissolve 0.592g of SDS in 210mL of ammonia water and 270mL of deionized water mixture stirred at 68°C at 300rpm, add 1.408g of CTAB after being dissolved until clarified, and quickly add 10mL of TEOS after clarifying again, continue heating for 2 hours and pump out filtered, washed with deionized water and ethanol in turn, and dried at 60°C. The above dried product was calcined in an air atmosphere at 550° C. for 4 h to remove the template agent to obtain the target product. It can be seen from Figure 1 that the formed product is in the shape of overlapping vesicles and the pore wall is not obvious. (R=0.36) Example 2

Dissolve 0.665g of SDS in 210mL of ammonia water and 270mL of deionized water mixture stirred at 68°C at 300rpm, add 1.335g of CTAB after being dissolved until clarified, add 10mL of TEOS quickly after clarification again, continue heating for 2 hours and pump filtered, washed with deionized water and ethanol in turn, and dried at 60°C. The above dried product was calcined in an air atmosphere at 550 °C for 4 h to remove the template agent to obtain the target product (R=0.4).

The transmission electron micrograph on the left of Figure 2 shows the morphology and size of the pore structure of the synthesized continuous aggregated vesicles, and the scanning electron micrograph on the right of Figure 2 further confirms the existence of the vesicle structure, and the vacuolar structure is clearly visible. The left side of Figure 3 is the small-angle X-ray diffraction pattern of the product. It can be seen that the two peaks appearing at the 2θ angle are in line with the characteristics of the layered phase structure, and they are calibrated as 100 and 200, which are related to the layered pore wall structure in the vesicle structure. . The interlayer thickness of the pore wall is approximately 5.1nm measured from the transmission electron microscope picture, and the layer thickness calculated from the small angle X-ray diffraction pattern is 5.3nm, which is very close, indicating that the agreement is good. The right side of Figure 3 is the nitrogen adsorption-desorption curve of the product, which is consistent with the Type IV adsorption isotherm defined by the International Union of Pure and Applied Chemistry (IUPAC), indicating its mesoporous structure characteristics. The rising curve of the adsorption high partial pressure region is basically parallel to the desorption falling curve, which belongs to the H4 type hysteresis loop classification, and belongs to the slit channels with uniform shape and size, that is, the interlayer pores. The sharp rise of the adsorption curve in the high partial pressure region indicates the presence of larger pores, corresponding to vesicular pores.

Embodiment three

Dissolve 0.740g of SDS in 210mL of ammonia water and 270mL of deionized water mixture stirred at 68°C at 300rpm, add 1.260g of CTAB after being dissolved until clarified, and quickly add 10mL of TEOS after clarifying again, continue heating for 2 hours and pump filtered, washed with deionized water and ethanol in turn, and dried at 60°C. The above dried product was calcined in an air atmosphere at 550° C. for 4 h to remove the template agent to obtain the target product. It can be seen from Figure 4 that the size of the vesicles becomes smaller and the continuous aggregation is more compact (R = 0.44).

Embodiment four

Take 36.575g of SDS and dissolve it in 11.55L of ammonia water and 14.85L of deionized water mixture stirred at 68°C at 300rpm, add 73.425g of CTAB after the solution is clarified, add 550mL of TEOS quickly after clarification again, and continue heating for 2 hours Afterwards, filter with suction, wash with deionized water and ethanol in sequence, and then dry at 60°C. The above dried product was calcined in an air atmosphere at 550° C. for 4 h to remove the template agent to obtain the target product. It can be seen from Figure 5 that under the conditions of mass production, the basic characteristics of the vesicle aggregate morphology have not changed, the size is still within the range of small batch synthesis, and the characteristics of multi-level channels are obvious (R=0.4).

Wherein R is: n (SDS) represents the moles of sodium dodecylsulfonate, n (CTAB) represents the moles of cetyltrimethylammonium bromide, R=n (SDS)/[ n(SDS)+n(CTAB)], which means the molar ratio of the anionic surfactant sodium dodecylsulfonate in the total surfactant dosage.

Claims (4)

1. the continuous aggregate vesica of a silicon-dioxide material, is characterized in that, pattern is the hollow blister of continuous aggregate bivalve layer, is of a size of 20～100nm, and loose density is 0.01～0.10g/cm ³; Pore size distribution is multi-stage porous, is divided into the vesica hole of hole between the wall of 2～4nm and 20～40nm, and pore wall thickness is 4～6nm; Specific surface area is 600～1100m ²/ g.

2. a method for the continuous aggregate vesica of a large amount of preparation silicon-dioxide claimed in claim 1 material, is characterized in that, comprises that step is as follows:

(1) SDS:CTAB:TEOS:H in molar ratio ₂o:NH ₄oH is 1:(1～2.33): (16～20): 6143.9:557.3 takes sodium laurylsulfonate SDS, cetyl trimethylammonium bromide CTAB: tetraethoxy TEOS, H ₂o and 25wt% ammoniacal liquor;

(2) SDS is dissolved at 68 ℃ to deionized water and the ammonia water mixture in stirring, to clarification, add CTAB, until solution, after secondary clearing, add fast TEOS again, at this temperature, continue reaction 2h, by reactant suction filtration, successively with after deionized water, washing with alcohol 60 ℃ dry;

(3) after dry, use retort furnace at 550 ℃, to calcine that 4h removes template SDS and CTAB obtains target product.

3. method according to claim 2, is characterized in that, SDS:CTAB:TEOS:H in molar ratio in step (1) ₂o:NH ₄oH is that 1:1.5:18.1:6143.9:557.3 takes sodium laurylsulfonate SDS, cetyl trimethylammonium bromide CTAB: tetraethoxy TEOS, H ₂o and 25wt% ammoniacal liquor.

4. method according to claim 2, is characterized in that, the speed stirring described in step (2) is 300rpm.