Modification and application of mesoporous silica materials

Overview of mesoporous silica materials

Mesoporous silica material is a new type of material with pore size between micropore and macropore. According to the different pore sizes, the International Association of pure and Applied Chemistry (IUPAC) divides porous materials into three categories: microporous materials less than 2nm; The mesoporous material is between 2-50 nm; Those larger than 50 nm are macroporus materials.

According to the chemical composition, mesoporous materials can be divided into silicon-based and non silicon-based. Non silicon based mesoporous materials mainly include transition metal oxides, phosphates and sulfides. Compared with non silicon based mesoporous materials, the research of silicon-based mesoporous materials is more mature. Silica based mesoporous materials have the characteristics of regular pore structure and narrow pore size distribution. They are widely used in the fields of separation and purification, adsorption, catalysis, sensing, drug loading and sustained release.

Application of mesoporous silica materials

Mesoporous silica materials have excellent adsorption properties: ordered pore structure; The pore size distribution is single and adjustable, and the mesoporous shape is diverse. It plays a very important role in the fields of adsorption and separation, industrial catalysis, biomedicine, environmental protection and so on.

1. High specific surface area and large pore volume make it can be used as drug carrier or catalytic carrier in the field of medicine and catalysis.

2. The single pore size distribution and wide regulation range make it possible to prepare semiconductor materials as a controllable reactor.

3. The unique pore wall structure and micro morphology make it have a very good application prospect in the fields of Optics and electricity.

4. With good thermal and hydrothermal stability, and a large number of silicon hydroxyl groups attached to the surface, it can be chemically modified to become a promising new composite carrier.

Modification of mesoporous silica materials

The surface of mesoporous silica material contains a large number of hydroxyl groups, the surface energy is high, it is easy to agglomerate, which affects the dispersion of organisms, the uniformity becomes worse, and the utilization rate of assembly materials is significantly reduced. Therefore, the modification can reduce the surface energy and effectively improve the dispersion rate. There are many modification methods, including surface physical modification and surface chemical modification.

Surface physical modification mainly modifies the surface of particles by means of adsorption, wrapping and so on.

Surface chemical modification is mainly modified by coupling agent. Through the interaction between the coupling agent containing organic functional groups and mesoporous silica materials, the functional groups are covalently grafted onto the pore wall of mesoporous materials to realize the functionalization of mesoporous silica materials. There are two common surface chemical modification methods: CO polycondensation and post grafting.

Co condensation, that is, one-step preparation method, is to add organic coupling agent and inorganic source into the system at the same time under the action of template, and introduce functional groups into the pores while generating mesoporous structure.

Preparation of mesoporous silica materials by CO polycondensation

Advantages: it can prepare functional mesoporous silica materials with high loading and uniform dispersion.

Disadvantages: the preparation conditions are acidic or alkaline. Many coupling agents are extremely unstable and easy to decompose or denature under these conditions. At the same time, the excessive amount of functional groups will also destroy the formation of mesoporous structure.

Post synthesis is to prepare mesoporous silica materials first, then add coupling agent to the prepared mesoporous silica materials and reflux in organic solvent.

Schematic diagram of preparation of mesoporous silica by post grafting method

Features: the reaction is usually carried out under the protection of nitrogen, which can inhibit the hydrolysis of the coupling agent itself. The whole modification process will not damage the structure of the mesoporous material itself, and can well control the degree of functionalization. Therefore, post grafting method is more used.

On this basis, more complex grafting also appeared one after another, such as multi-step grafting. Many researchers have modified mesoporous silica by different methods to improve its ability to treat heavy metal ions in wastewater.

Coating method

The principle of coating method is similar to that of grafting method. The silicon hydroxyl group on the surface of mesoporous silica reacts with organosilane. At the same time, with the help of a small amount of water, the self polymerization reaction between organosilane can also occur, so as to form a layered material. The coating method can produce a large number of organic functional groups, which may become a good adsorbent when the pore structure of the material is not significantly blocked.

Impregnation method

Impregnation method is a method of loading one or several active components on the carrier through impregnation carrier. Usually, the carrier is contacted with the active component solution to adsorb or store the active component solution in the carrier capillary, remove the excess solution, and then prepare the adsorbent through drying and activation.

Mosaic method

The unique, regularly arranged and continuously adjustable pore structure of ordered mesoporous materials undoubtedly provides good material conditions for the study of nanoparticles. Thus, it provides a powerful basis for studying the physical and chemical properties of mesoporous materials from the microscopic point of view. Using the mosaic method, ion, atom or molecular clusters with uniform, stable and adjustable size are loaded and formed in the mesoporous channels,

Price of mesoporous silica materials

The price of mesoporous silica materials will vary with the production cost, transportation cost, international situation, exchange rate and market supply and demand of mesoporous silica materials. Tanki new materials Co., Ltd. aims to help industries and chemical wholesalers find high-quality and low-cost nano materials and chemicals by providing a full range of customized services. If you are looking for mesoporous silica powder, please feel free to send an inquiry to obtain the latest price of mesoporous silica.

Suppliers of mesoporous silica materials

As a global supplier of mesoporous silica materials,Tanki new materials Co., Ltd. has rich experience in the performance, application and cost-effective manufacturing of advanced engineering materials. The company has successfully developed a series of powder materials (including boron carbide, aluminum carbide, titanium carbide, etc.), high-purity targets, functional ceramics and structural devices, and provided OEM services.