Activated Alumina – An Introduction
Activated Alumina is a widely used form of desiccant, mainly employed for the purification and treatment of water made available to businesses and households by municipal corporations. Activated Alumina has two main highlights- it is a very porous material and has a large surface area. This helps the Activated Alumina to absorb more moisture/impurities over a vast area. Along with its use as a popular desiccant, Activated Alumina is also widely used to remove impurities and harmful substances like fluoride, arsenic and selenium from the water being used by households. Activated Alumina is manufactured by dehydroxylating aluminium hydroxide till a highly porous material is obtained.
Role of Activated Alumina in Water Treatment
As mentioned earlier, one of the major uses of Activated Alumina is in the treatment of water being supplied to town and cities by their respective municipal corporations. Activated Alumina is mainly used to remove dangerous substances like fluoride, which is very harmful to the human body as it can cause fluorosis. When the water comes in contact with Activated Alumina, then the fluoride levels are seen to fall from 10.00 ppm to below 1.0 ppm. This is the correct level of fluoride recommended for water made available to households and businesses.
Another advantage of using Activated Alumina is that it covers a large surface area. So when more water molecules are in contact with the Activated Alumina, more impurities will be removed from the water. Other factors needed for efficient water treatment include more activated alumina balls in the filter, lower water temperature and lower pH levels (i.e. the water should be more acidic).
Regeneration of Activated Alumina
Another major advantage of using Activated Alumina is that it can easily be regenerated and thus proves to be quite cost-effective for municipal corporations around the world. Once the Activated Alumina has been used, it is regenerated with the help of a dilute caustic solution. This caustic solution removes all the absorbed fluoride and other impurities from the Activated Alumina filter and then it is all ready to be used once again. This regeneration quality saves a lot of time and money for municipal corporations as they can use the same Activated Alumina many times over.