One of the major users of desiccants is the water purifiers we have at our home. These purifiers use the desiccant Activated Alumina to purify water for drinking purposes. The Activated Alumina uses the adsorption process for completing the task. Under this process, the water passing through sticks to the alumina in between the tiny pores while the air moves forward. As the water molecules cannot pass through, the air is completely dry as it crosses the filter. The huge surface-area-to-weight ratio of the Activated Alumina tremendous help with the water purification process. This ratio is high because of the “tunnel shaped” holes in the desiccant.
Another important use of activated alumina adsorbent is in the removal of fluoride from drinking water. In many parts of the world, water is contaminated with fluoride, which can lead to fibrosis. So in these regions activated alumina water filters are installed to bring down the fluoride levels. The activated alumina adsorbent lowers the fluoride levels from 0.5 ppm to below 0.1 ppm. The longer the fluoride containing water is in contact with the alumina filter, the lesser amount of fluoride will be present in the final, filtered drinking water. The level of fluoride is indirectly proportional to the amount of activated alumina adsorbent in the filter.
Once installed, the activated alumina water filter efficiently filters lower temperature water as well as lower pH water. Municipal corporations across the world also use activated alumina adsorbent to get rid of toxins like arsenic from water.
What It Is Made From
The activated alumina water filter is made from aluminum hydroxide. The latter is dehydroxylated in such a manner that it results in a highly porous matter, which has a surface area well over 200 m²/g. Activated alumina has the same chemical composition as precious stones like sapphire and ruby i.e alumina Al2O3.
Other than water filtration, Activated Alumina finds use in many adsorbent and catalyst operations like the adsorption of catalysts in polyethylene production and as a special adsorbent for chemicals like arsenic. It is also used to remove sulfur traces from gas streams.