Introduction and application of mercerized zeolite

Mercerized zeolite, also known as luminous zeolite. It is one of the main mineral components of zeolite ore. It is in the plagioclase system, with needle-like and fibrous crystals and bundled and radiating aggregates. White, light yellow or rose color. Silky luster or glassy luster.

Silky zeolite has excellent heat resistance, acid resistance and water vapor resistance. It is widely used as adsorbent for gas or liquid mixture separation and catalyst for hydrocarbon cracking, hydrocracking, reforming, dewaxing and synthesis of dimethylamine, isomerization of alkanes, alkylation of polycyclic aromatic compounds, etc. It is also used as desiccant and adsorbent.

In its crystal structure, there are not only tetradentate, hexadentate and octadentate rings, but also pentadentate rings, and the proportion of pentadentate rings is large. The pentacycles are connected in pairs, i.e., two pentacycles share two tetrahedra. The paired quintuplet rings can be connected to another paired quintuplet ring by an oxygen bridge, and then a quadruplet ring is formed at the place of connection. If further rings are connected to each other, they can be enclosed to form octet rings and dodecet rings. In fact, the crystals of filamentous zeolite are made up of many such layers overlapped together and linked in a proper way.

Therefore, many straight pores are formed in the crystals of filamentous zeolite, and the largest diameter of them is the straight pores composed of dodecametric rings, which are the main pore channels of filamentous zeolite, with elliptical cross section, the long axis diameter is 0.695nm and the short axis diameter is 0.581nm, and they seem to be a bundle of tube bundles, which is very different from the cage-shaped pores of A, X and Y type zeolites. In fact, the straight cylindrical pores are twisted to some extent, and the layers are not squarely overlapping each other, but are displaced from each other.

Therefore, the average diameter may be reduced from 0.66 nm to 0.4 nm. There are also small pores between the main pores of mercerized zeolite that communicate with each other, but because the pore size of these small pores (about 0.39 nm) is small, it is not easy for general molecules to enter, and they can only enter and exit in the main pores. The crystals of mercerized zeolite can be considered as two degrees of space for molecular access, while the A-type, X-type and Y-type are three degrees of space.

Because of its high silica-aluminum ratio and many five-membered rings, mercerized zeolite has a high acid resistance and thermal stability. It is insoluble in acid at room temperature. It is commonly found in the fissures and pores of medium-acid volcanic rocks, and is often coeval with plagioclase zeolites.

Widely used in chemical, environmental protection, agriculture, light industry, petroleum, construction and other sectors.