Honeycomb zeolite molecular sieve

The adsorption mechanism of honeycomb zeolite molecular sieve mainly includes two types: adsorption and desorption. When molecules in the solution enter the honeycomb zeolite molecular sieve, they will interact with the pore walls to form physical or chemical bonds. These bonds adsorb molecules into the pores of zeolite molecular sieves. When external environmental conditions change, such as changes in concentration in a solution, adsorbed molecules may be desorbed by honeycomb zeolite molecular sieves.

　　Honeycomb zeolite molecular sieveZeolite molecular sieve is a type of aluminosilicate crystal with a regular microporous structure. It not only has the inherent physical and chemical properties of general inorganic membrane materials, but also has excellent properties. Its uniform and regular crystal pore system with specific spatial orientation and adjustable Si/Al ratio of the scaffold endow zeolite molecular sieve membrane with screening, shape selection and adjustable surface properties, making it an excellent porous membrane material for achieving efficient separation and membrane catalytic reaction integration at the molecular level. It is one of the membrane materials with potential and prospects.

After activation of zeolite molecular sieve, water molecules are removed and the remaining atoms form a cage structure. There are many holes of a certain size in molecular sieve crystals, and there are many holes of the same diameter (also known as "windows") connected between the holes. Due to its ability to adsorb molecules smaller than its pore size into the interior of the cavity, while repelling molecules larger than its pore size outside its cavity, it plays a role in screening molecules, hence the name molecular sieve.

　　Honeycomb zeolite molecular sieveThe adsorption mechanism includes two types: adsorption and desorption. When molecules in the solution enter the honeycomb zeolite molecular sieve, they will interact with the pore walls to form physical or chemical bonds. These bonds adsorb molecules into the pores of zeolite molecular sieves. When external environmental conditions change, such as changes in concentration in a solution, adsorbed molecules may be desorbed by honeycomb zeolite molecular sieves.

The commonly referred ion exchange refers to the exchange of compensating cations outside the framework of zeolite molecular sieves. The compensating ions outside the framework of zeolite molecular sieves are generally protons and alkali metals or alkaline earth metals, which are easily ion exchanged into various valence states of metal ion type zeolite molecular sieves in aqueous solutions of metal salts.

Ions are more prone to migration under certain conditions, such as in aqueous solutions or at higher temperatures. In aqueous solutions, due to the different ion selectivity of zeolite molecular sieves, they can exhibit different ion exchange properties. The hydrothermal ion exchange reaction between metal cations and zeolite molecular sieves is a free diffusion process. The diffusion rate constrains the exchange reaction rate.

Ion exchange can change the pore size of zeolite molecular sieves, thereby altering their performance and achieving the goal of selective adsorption and separation of mixtures.

After ion exchange, the number, size, and position of cations in zeolite molecular sieves change. For example, the exchange of high valence cations with low valence cations reduces the number of cations in zeolite molecular sieves, often resulting in positional vacancies and an increase in pore size; When ions with larger radii exchange ions with smaller radii, their pores are easily blocked, resulting in a decrease in the effective pore size.