Molecular sieve manufacturer: position and structure of aluminum in zeolite molecular sieve

The aluminum atom in the framework position of molecular sieve makes the framework of molecular sieve present negative electricity, and requires cation to pair with it to achieve charge balance. This also makes molecular sieves have a series of special properties, such as ion exchange ability and catalytic reaction activity.
In general, the number of active centers is consistent with the number of aluminum atoms in the skeleton. The hydrophilicity and hydrophilicity of molecular sieves are also closely related to the content of skeleton aluminum, which can affect the ability of molecular sieves to adsorb polar and non-polar molecules. Therefore, the performance of molecular sieve is not only related to its skeleton structure, but also related to the ratio of silicon to aluminum. Today, molecular sieve manufacturer will explain the position and structure of aluminum in zeolite molecular sieve.
The distribution of aluminum is also an important factor affecting the performance of molecular sieve. However, its impact on the performance of molecular sieve can be analyzed from two different perspectives: first, the aluminum-rich region on the crystal of a single molecular sieve, and second, the distribution of aluminum on the lattice position T. The lattice position T of molecular sieves is usually occupied by four-coordinated silicon atoms or aluminum atoms. The number of lattice position T in molecular sieve and its degeneracy, as well as the spatial distribution of aluminum are related to the framework structure of molecular sieve. On a single molecular sieve particle with a specific topological structure, aluminum is not necessarily uniformly distributed on the whole particle, but may be enriched in some areas. The spatial distribution of aluminum is generally related to the distribution of silicon and aluminum in the lattice position of the whole molecular sieve framework.
Aluminum in molecular sieve is very important to its performance. This makes it very important to analyze the structure of aluminum, its position in the crystal and the position of its skeleton lattice. The structure of molecular sieves is closely related to pretreatment conditions and characterization conditions. Moreover, the skeleton structure of molecular sieve is very sensitive to water vapor. At room temperature, part of the four-coordinated skeleton aluminum atoms in hydrogen-type molecular sieves can be converted into eight-coordinated aluminum species, and the amount of conversion depends on the topological structure of molecular sieves and the ratio of silicon to aluminum. If the molecular sieve is treated with alkali such as ammonia, the conversion of aluminum species is completely reversible.
The understanding of the distribution of aluminum in the lattice position of the molecular sieve framework and the position of the catalytic active center can better relate the acidity, selectivity, stability and other catalytic properties of aluminosilicate molecular sieves. At present, a variety of characterization techniques have been applied or developed to analyze the distribution of aluminum skeleton lattice position in molecular sieves. 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.