About 4A molecular sieve activation

About 4A molecular sieve activation

A molecular sieve has a pore size of 4A, which can adsorb low-molecular compounds, such as water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc. It does not adsorb any molecules (including propane) with a diameter greater than 4A, and has high selective adsorption to water performance.
For any other molecule, it is one of the commonly used molecular sieve varieties in the industry.
It is possible to evaporate water in a large space of 110°C, but it is impossible to drain the water in the pores of the molecular sieve.
Therefore, in the laboratory, dehydration can be activated by drying in a muffle furnace at a temperature of 350°C and drying under normal pressure for 8 hours (if there is a vacuum pump, it can be dried for 5 hours) at 150°C, it will activate The molecular sieve is cooled to about 200°C (about 2 minutes) in the air and stored in a desiccator immediately.
If conditions permit, use dry nitrogen for protection during cooling and storage to prevent moisture in the air from being adsorbed.
The old molecular sieve will produce pollutants after being used, and the activation temperature is not only as high as 450°C, but also water vapor or inert gas (nitrogen, etc.) will be introduced to replace other substances.
If not stored properly under normal conditions, molecular sieves will adsorb water, carbon dioxide and other substances. In order to ensure better adsorption of adsorbed substances, it is recommended to regenerate before use