The 4A molecular sieve has a pore size of 4A, which can filter any molecule below 4A, thereby adsorbing substances larger than 4A, such as water, methanol, ethanol, hydrogen sulfide, sulfur dioxide, carbon dioxide, ethylene, propylene, etc., which are currently used more. A molecular sieve. Do you know the calcination temperature of 4A molecular sieve?
Water can be evaporated in a large space of 110 ° C, but it is impossible to discharge 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. The activated molecular sieves were cooled to about 200 ° C (about 2 minutes) in air and immediately stored in a desiccator. If conditions permit, use dry nitrogen protection during cooling and storage to prevent moisture in the air from being adsorbed. The old molecular sieve after use has contaminants. When activated, it should not only have a temperature of up to 450 ° C, but should also have water vapor or an inert gas (nitrogen, etc.) instead of other substances in the molecular sieve.
As the calcination temperature increases, the pore size and compressive strength increase, but the specific surface area, pore volume and exchange cation capacity decrease, and the microstructure changes significantly. This complex adsorbs Cd(II). From the removal of Cd (II) effect, the appropriate calcination temperature should not be higher than 500 ° C; considering the material strength and adsorption properties, the 4A molecular sieve calcination temperature is 600 ° C.