Activated Alumina is a white porous spherical particles, uniform size, smooth surface, mechanical strength, high moisture absorption, water absorption expansion does not crack after not maintain the status quo, non-toxic, odorless, insoluble in water, ethanol. It has many pores Road, specific surface area can be used as sorbent, desiccant and catalyst. According to the adsorption material and also to determine the strength of the polarity of water, oxides, acetic acid, alkali and other strong affinity, is a water depth of micro-desiccant, adsorbent is adsorbed polar molecules.