What Effect Does Activated Alumina Add Phosphorus To Have?
Activated alumina is a relatively common material, so when we use it, sometimes, because of the better performance and performance characteristics of the product, we add some products to it to make a change and improvement, and adding phosphorus is one of the more frequently added substances, so why on earth should it be added? What is its function?
The stabilizing mechanism of phosphorus on activated alumina. The more uniform phosphorus is distributed in alumina, the stronger the bond, and the stronger its stabilizing effect. The different ways of introducing phosphorus change the coordination of aluminum ions in alumina. The more six-coordinated aluminum ions, the more stable the alumina.
Phosphorus exists in an amorphous state on the surface of alumina, which changes the number and properties of surface hydroxyl groups, inhibits the dehydroxylation and sintering of alumina and particle growth, and improves its thermal stability.
Phosphorus changes from -3 valence to +5 valence during the hydrolysis and calcination process, which increases the anion vacancies in the alumina, thereby increasing the surface alkalinity of the activated alumina.
Phosphorus exists in the bulk phase of alumina in the form of monophosphate, which inhibits the bulk diffusion of aluminum ions, thereby increasing the alpha phase transition temperature of alumina. In addition, in a water vapor environment, Al-OH is replaced by P-OH, which is difficult to remove, so the hydrothermal stability of alumina is greatly improved.
The addition of phosphorus to activated alumina can change the internal structure of the product, so that it can better improve the performance advantages of the product. When used for different purposes, the added products are also different.
