Molecular sieve manufacturer: method of constructing mesoporous and macroporous structure in molecular sieve

In recent years, the number of methods for constructing molecular sieves with secondary pore structure has shown a rapid growth trend, and these methods have also been widely used in the synthesis of multistage pore molecular sieves with different skeleton structures. Today, molecular sieve manufacturer will introduce several mainstream methods to you.
Post-modification treatment: usually refers to the method of selectively removing skeleton atoms through steam aging, acid treatment, alkali treatment or other complex reagent treatment, and introducing secondary pore structure into molecular sieve. This can generally be achieved by dealumination, desilication or selective removal of other skeleton atoms.
Nevertheless, it is still difficult to control the morphology, pore volume and connection mode of secondary pore structure in a controllable way. In addition, the post-modification treatment will inevitably change the skeleton composition of molecular sieve and make the skeleton structure of molecular sieve amorphous to a certain extent. Therefore, in practical applications, it is usually difficult to solve the contradiction between the improvement of physical and chemical properties of molecular sieves and the change of skeleton element composition. Another neglected influence is the change of morphology and surface properties of molecular sieves after post-modification, which will also have a significant impact on the adsorption performance of molecular sieves.
Template method: template method is a more direct method to construct mesoporous structure, which has also been widely used in the synthesis of mesoporous materials. Unlike the post-modification method, the template is added in the crystallization process of molecular sieve and then selectively removed. Therefore, the composition of the framework structure of the molecular sieve can be determined by the composition of the precursor gel. At present, many different templates have been used in the synthesis of multistage porous molecular sieves. According to their structure and rigidity, these templates can be divided into hard templates and soft templates.
Compared with the post-modification method, the template method shows several advantages. Firstly, mesoporous structure can be introduced into molecular sieves without affecting the skeleton composition. Therefore, the pore structure and skeleton structure characteristics of molecular sieves can be studied respectively through template method. Secondly, in principle, the pore volume, pore morphology and interconnection mode of molecular sieve can be more effectively adjusted by selecting appropriate template. However, in the process of crystallization and removal of template, the influence of these templates on the chemical composition of molecular sieve and the phase purity of the final product should not be ignored.
In addition, mesoporous molecular sieves can also be synthesized without templates. It is also possible to load the molecular sieve particles with small particle size on the carrier with mesoporous structure to generate composite materials with mesoporous structure and so on. It can be seen that up to now, there are quite a number of methods that can be used to synthesize mesoporous and macroporous molecular sieve materials. Each method has advantages that other methods do not have, and they can complement each other. Hunan Providence New Materials Co., Ltd is a professional molecular sieve manufacturer which can provide USY zeolite, NaY zeolite, REY zeolite, ZSM-5 zeolite, welcome to consult.