Activated alumina has excellent adsorption effects on de-fluorination based on stable capacity. The product has strong strength; hard wearing; keep no soft; no expansive; no powder; and no crack under soaking. It is widely used in oil pyrolysis gas, ethylene propylene gas in the deep drying and hydrogen, air separation unit, instrument air drying machine, fluoride removal in aquae hydrogenii dioxide. It can also eliminate sulfur gas hydrogen, sulfur dioxide, hydrogen fluoride, hydrocarbons and other pollutants in waste water, particularly adapt to fluoride removal disposal in fluorine-containing water.