The pore size range of activated alumina varies depending on the preparation method and treatment conditions. Generally speaking, the pore size distribution of activated alumina is relatively uniform, mainly within the following two ranges:

Smaller pore size range of activated alumina: There are some smaller pore sizes in activated alumina, which are usually between 2 and 50 nanometers. The pore size within this range plays an important role in improving its catalytic and adsorption properties. Especially in certain specific catalytic reactions and adsorption processes, smaller pore sizes can provide more surfactant sites and more efficient mass transfer pathways.

Larger pore size range obtained by special methods: Through specific preparation methods, such as adding water-soluble organic polymer as pore forming agents, alumina with a pore size range of 100~250 nanometers can be obtained. This method obtains activated alumina with a larger pore size by controlling the precipitation process of aluminum hydroxide and passing the pores after calcination.

Overall, the pore sizes of activated alumina cover different sizes from less than 50 nanometers to hundreds of nanometers. This porous structure makes the activated alumina have a very large specific surface area (usually between 100 and 400 square meters/g), thus having high adsorption and catalytic activity. Therefore, activated alumina is widely used as a catalyst and catalyst support for chemical reactions, as well as desiccants, purifiers, etc. for gases and liquids.