Activated Alumina is a high-surface-area, highly porous form of aluminum oxide. It can adsorb gases and liquids without changing its form. It works as a desiccant by adsorption. As air passes through the alumina, water in the air bonds and becomes trapped on the AA desiccant beads. Air that passes through an activated alumina filter or dryer can achieve -40 or -100 dewpoints. AA desiccant will not fall apart or soften if exposed to water.