阅读说明：本技术 一种快速高效脱除介孔氧化硅材料模板剂的方法 (Method for quickly and efficiently removing mesoporous silicon oxide material template agent ) 是由 冯国栋 苗康康 罗小林 郭家乐 王伟 裴霏 郭思凡 于 2019-12-04 设计创作，主要内容包括：本发明公开了一种快速高效脱除介孔氧化硅材料模板剂的方法,该方法包括以下步骤：(1)分别称取未脱除模板剂的介孔氧化硅与高氯酸铵于坩锅中,加入乙醇,搅拌混合均匀,干燥；用锡箔纸封住坩锅口,并在锡箔纸上均匀扎出针眼大小的孔；(2)将坩锅置于马沸炉中升温至450～460℃,保温2-8min,取出坩埚,冷却,得到脱除模板剂的介孔氧化硅。本发明方法实现了快速高效脱除介孔氧化硅材料中的模板剂,同时显著降低介孔氧化硅材料表面羟基的损失,整个处理过程简单、可控、省时节能、成本低廉,可大规模生产；与焙烧法相比较,本发明的高氯酸铵热爆法所得介孔材料的比表面积、孔径与孔体积均较大。(The invention discloses a method for quickly and efficiently removing a mesoporous silica material template agent, which comprises the following steps: (1) respectively weighing mesoporous silicon oxide without template agent removal and ammonium perchlorate in a crucible, adding ethanol, stirring and mixing uniformly, and drying; sealing the opening of the crucible by using the tin foil paper, and uniformly pricking holes with the sizes of the needle holes on the tin foil paper; (2) and (3) placing the crucible in a muffle furnace, heating to 450-460 ℃, preserving heat for 2-8min, taking out the crucible, and cooling to obtain the mesoporous silicon oxide with the template agent removed. The method realizes rapid and efficient removal of the template agent in the mesoporous silicon oxide material, simultaneously remarkably reduces loss of hydroxyl on the surface of the mesoporous silicon oxide material, has simple and controllable whole treatment process, saves time and energy, has low cost, and can be produced in a large scale; compared with a roasting method, the mesoporous material obtained by the ammonium perchlorate thermal explosion method has larger specific surface area, pore diameter and pore volume.)

1. A method for quickly and efficiently removing a mesoporous silica material template is characterized by comprising the following steps:

(1) respectively weighing mesoporous silicon oxide without template agent removal and ammonium perchlorate in a crucible, adding ethanol, stirring and mixing uniformly, and drying; sealing the opening of the crucible by using the tin foil paper, and uniformly pricking holes with the sizes of the needle holes on the tin foil paper;

(2) and (3) placing the crucible in a muffle furnace, heating to 450-460 ℃, preserving heat for 2-8min, taking out the crucible, and cooling to obtain the mesoporous silicon oxide with the template agent removed.

2. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 1, wherein the mass ratio of the mesoporous silica without the template to the ammonium perchlorate in the step (1) is (3-5): 1.

3. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 2, wherein the mesoporous silica is selected from at least one of the following: SBA-15, MCM-41, FDU-5, KIT-6, HMS, MSU.

4. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 1, wherein the dosage ratio of the mesoporous silica without the template to the ethanol is 1 g: (80-120) ml.

5. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 1, wherein the stirring time in the step (1) is 5-10 min.

6. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 1, wherein the temperature rise rate in the step (2) is 10-25 ℃/min.

7. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 1, wherein the heat preservation time in the step (2) is 3-5 min.

8. The method for rapidly and efficiently removing the mesoporous silica material template according to claim 7, wherein the sum of the heating time and the heat preservation time in the step (2) is 20-45 min.

Technical Field

The invention belongs to the technical field of preparation of inorganic nonmetallic materials, and particularly relates to a method for quickly and efficiently removing a mesoporous silicon oxide material template agent.

Background

The mesoporous silica material has a controllable pore structure and a high specific surface area, so that the mesoporous silica material is widely applied to the related technical fields of catalysis, drug loading, adsorption separation, sensors, nano material preparation and the like. The mesoporous material can be obtained only after the template agent in the newly synthesized inorganic-organic composite mesostructured material is removed, so that the removal of the template agent is an essential step in the synthesis process of the mesoporous material. However, different removal methods can affect the properties of the resulting mesoporous material. The roasting method and the extraction method are two methods for removing the surfactant which are most widely applied at present, and are also the most effective methods. The baking method generally adopts the speed of 1-2 ℃/min to raise the temperature in the furnace to 550 ℃, and then the temperature is kept for about 6 hours until the surfactant is completely burnt and removed, so as to obtain the mesoporous material (nat. Mater.2003,2, 159-163). Although calcination is one of the most common methods, it has significant disadvantages: (1) the roasting demoulding is carried out at high temperature, generally the roasting temperature is equal to or higher than 550 ℃, and the energy consumption is very high; (2) the roasting process usually takes 10-15 hours; (3) the long-time high-temperature roasting easily causes the collapse of the mesoporous silica framework structure, and has poor demolding applicability to mesoporous silica materials with poor thermal stability, such as MCM, MSU and the like. The extraction method is to remove the surfactant by extracting for many times with an organic solvent such as ethanol or tetrahydrofuran (chem. Mater.2001,13, 4760-3008). The extraction method is carried out at normal temperature, so that many defects of the roasting method can be overcome; meanwhile, the extraction method has some defects, such as complex treatment process, repeated extraction with organic solvent, usually 3-6 days, and difficulty in thoroughly removing the surfactantBesides, the method wastes time and labor, and brings a series of troubles for subsequent experiments; in addition, the organic waste liquid generated by the extraction method pollutes the environment. Besides the two common methods, an ultraviolet radiation method, a microwave elimination method and an ammonium perchlorate solution oxidation method exist, but the methods have obvious defects. The ultraviolet radiation method requires a long time (more than 10 h), has low demolding rate, and is not suitable for removing the surfactant template in a large amount of samples (chem. Mater.2000,12, 3842-3847). The microwave elimination method needs concentrated nitric acid, concentrated sulfuric acid, acidic potassium permanganate and H₂O₂When the reaction solution with strong acidity and strong oxidizing property is subjected to constant-acidity reaction, the strong-acidity or strong-oxidizing waste liquid generated after demolding pollutes the environment, and complicated and high-cost waste liquid treatment is required; meanwhile, the strongly acidic and strongly oxidizing reaction solution can cause the loss or oxidation and falling of some non-silicon active components in the mesoporous material, and is not suitable for the removal of the template of the doped mesoporous silicon oxide material (chem. Commun.2002, 1186-1187). The ammonium perchlorate solution oxidation method is that a certain amount of mesoporous silicon oxide material before demoulding is placed in a hydrothermal kettle, a proper amount of mixed solution of ammonium perchlorate and nitric acid is added, the mixture is heated for 6-12 hours at the temperature of 80-120 ℃, and the organic template agent is removed through the strong oxidation of the system. Ammonium perchlorate solution oxidation methods are less in use and have more obvious defects: firstly, the method has longer treatment time (6-12 h) for demoulding; secondly, the selectivity of the method for demoulding is limited, and the method is only suitable for selectively removing a triblock copolymer PEO-PPO-PEO template agent in a mesoporous silicon oxide material (MicroporousMesoporous Mater.2009,118,513-517) in the current report. In summary, the removal of the template is an important step in the synthesis of the mesoporous silica molecular sieve, and has a great influence on the structural parameters of the finally formed mesoporous silica material. The existing methods have the insurmountable defect, and therefore, a new method needs to be developed, so that the template agent can be quickly and efficiently and completely removed at a lower temperature in a shorter time.

By searching the prior art at home and abroad, no document is found yet to provide a method for preparing a highly ordered mesoporous silicon oxide material with large specific surface area by removing a template agent in the mesoporous silicon oxide material by an ammonium perchlorate thermal explosion method.

Disclosure of Invention

Aiming at the defects of the existing method for removing the template agent from the mesoporous silicon oxide material, the invention aims to provide a method for removing the template agent from the mesoporous silicon oxide material by an ammonium perchlorate thermal explosion method, so as to obtain the highly ordered mesoporous silicon oxide material with large specific surface area.

In order to achieve the above technical objects of the present invention, extensive experimental studies and diligent efforts have been made, and the following technical solutions have been finally obtained: a method for quickly and efficiently removing a mesoporous silica material template comprises the following steps:

(1) respectively weighing mesoporous silicon oxide without template agent removal and ammonium perchlorate in a crucible, adding ethanol, stirring and mixing uniformly, and drying; sealing the opening of the crucible by using the tin foil paper, and uniformly pricking holes with the sizes of the needle holes on the tin foil paper;

(2) and (3) placing the crucible in a muffle furnace, heating to 450-460 ℃, preserving heat for 2-8min, taking out the crucible, and cooling to obtain the mesoporous silicon oxide material with the template agent removed.

Further preferably, in the method for rapidly and efficiently removing the mesoporous silica material template, the mass ratio of the mesoporous silica without the template to the ammonium perchlorate in the step (1) is (3-5): 1.

Further preferably, the method for rapidly and efficiently removing the template agent of the mesoporous silica material as described above, wherein the mesoporous silica is selected from at least one of the following: SBA-15, MCM-41, FDU-5, KIT-6, HMS, MSU.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent as described above, wherein the dosage ratio of the mesoporous silica without the template agent to the ethanol is 1 g: (80-120) ml.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent comprises the step (1) of stirring for 5-10 min.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent comprises the step (1) wherein the drying step is carried out at a temperature of 60-80 ℃.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent as described above, wherein in the step (1), the crucible opening is sealed by using tinfoil paper and is fastened by using iron wires.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent comprises the step (2) of heating at a rate of 10-25 ℃/min.

Further preferably, the method for rapidly and efficiently removing the mesoporous silica material template agent comprises the step (2) of keeping the temperature for 3-5 min.

Further preferably, in the method for rapidly and efficiently removing the mesoporous silica material template, the sum of the heating time and the heat preservation time in the step (2) is 20-45 min, and the removal rate of the template reaches more than 97%.

Compared with the prior art, the template agent removing method has the following advantages and progresses:

(1) the method is different from other template agent removal methods, and has the advantages of simple operation, low treatment temperature (low energy consumption) and short time required by the whole heat treatment process;

(2) compared with a roasting method, the method disclosed by the invention has the advantages that the template agent in the mesoporous silicon oxide material is quickly and efficiently removed, the temperature of the ammonium perchlorate thermal explosion method is reduced by 100 ℃, the time required by the whole heat treatment process is about 1/20 of the time required by the roasting method, and the specific surface area, the pore diameter and the pore volume of the obtained mesoporous material are larger;

(3) the method has the advantages that the removal rate of the template agent can reach more than 97 percent at medium and low temperature in a short time;

(4) the invention has simple treatment process, controllable process and low cost.

Drawings

FIG. 1 is a small-angle XRD (X-ray diffraction) pattern of an SBA-15 mesoporous material obtained by an ammonium perchlorate thermal explosion method in example 1 of the invention;

FIG. 2 is an SEM image of an SBA-15 mesoporous material obtained by thermal explosion of ammonium perchlorate in example 1 of the present invention;

FIG. 3 is a TEM image of a mesoporous material SBA-15 obtained by thermal explosion of ammonium perchlorate in example 1 of the present invention;

FIG. 4 is a thermogravimetric diagram of the SBA-15 mesoporous material obtained by the thermal explosion method (b) and the baking method (c) of the ammonium perchlorate (b) and SBA-15 without removing the template in example 1 of the present invention;

FIG. 5 is a nitrogen adsorption and pore size distribution diagram of the SBA-15 mesoporous material obtained by the ammonium perchlorate thermal explosion method in example 1 and the roasting method in comparative example 4.

Detailed Description

The technical solutions and technical effects of the present invention are clearly and completely described below with reference to the following examples, which are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. In addition, the specific technical operation steps or conditions not indicated in the examples are performed according to the technical or conditions described in the literature in the field or according to the product specification. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.