... alumina, there are many micro-paths, so the specific surface is large. It can be used as absorbent, ... trace water desiccant and the pole-moleculae absorbent, according to the absorbed molecule polarization, the attachment force is strong for water, ... just as the anion exchange resin, but the selectivity is much strong. The defluorination effect of the activated alumina is good.The capacity is stable. ...