The main characteristics of zeolite are as follows:
1. Porous structure: Zeolite is composed of tiny tetrahedral units (such as SiO4 and AlO4). These units are connected through oxygen atoms to form a three-dimensional skeleton structure. There are many regular or irregular pores in the skeleton, and the pores can accommodate water molecules and Other small molecules, such as metal ions, gas molecules, etc. The pore size of zeolite is generally between 0.2-1.5 nanometers, which can achieve the effect of molecular screening.
2. Strong exchangeability: The aluminum atoms in the zeolite skeleton will make the skeleton negatively charged. In order to maintain electrical neutrality, there will be a certain number of positively charged cations in the skeleton, such as sodium, potassium, calcium, magnesium, etc. These cations can exchange with water molecules or other cations in solution, thereby changing the properties and functionality of the zeolite. The exchange capacity of zeolite is generally between 0.5-3.5 mmol/g, which can achieve the effect of ion exchange.
3. High adsorption: Because the zeolite structure is porous and charged, it can effectively adsorb water molecules or other small molecules, such as ammonia, methane, benzene, etc. The adsorption capacity of zeolite is related to its structure, composition, temperature, pressure and other factors. It is generally between 0.1-0.5 g/g, which can achieve the effect of adsorption and separation.
4. Good catalysis: In addition to physical adsorption and ion exchange functions, zeolite also has chemical catalysis functions. It can accelerate or promote certain chemical reactions, such as cracking, isomerization, redox, etc. Zeolite catalysts have the advantages of high selectivity, high stability, and high activity, and can achieve catalytic conversion effects.