Alsorb-F a true grade of activated alumina has long been considered the best technology for fluoride removal from aqueous solutions.
These can be used to treat potable water for household and municipal units as well as a great solution for wastewater streams for removal of fluoride and arsenic. The adsorptive process is simply requiring a flow rate across the media with a minimum of five minutes empty bed contact time.
Alsorb-F is an aluminum oxide that is highly porous and exhibits high surface area. The crystal structure of alumina contains cation lattice discontinuities giving rise to localized areas of positive charge; this makes alumina attract various anionic species.
Our alumina balls have a high preference for fluoride compared to other anionic species and hence is an attractive adsorbent. It also does not shrink, swell, soften nor disintegrate when immersed in water.
The activated alumina was proposed for the first tune fir de fluoridation of water for domestic use in the 1930s. Then, the activated alumina has become popular de-fluoridation method.
The minimum adsorption capacity of Alsorb-F for fluoride is found to be 2.85mg /g of alumina. The activated alumina balls used as a fluoride filter can be regenerated by a solution of sodium hydroxide (NaOH), hydrochloric acid (HCL), sulfuric acid (H2SO4), and alum (KAL(SO4).
The capacity is bound by basic adsorption theory, the greater the concentration of impurity, the higher adsorptive capacity of the media.
The pH level also has a large impact on the ability to adsorb F. The optimum pH level should be from 5.5 to 6.5. Adjustment is easily accomplished with the same solutions as regeneration.
5 minute Empty Bed Contact Time achieves the best balance of adsorption capacity and capital cost.
Fluoride and Arsenic are strongly attracted to activated alumina leaving few competing water contaminants. Silica can reduce the adsorption capacity, although silica effect is limited when pH adjustment is employed. Systems, where silica levels are higher than 30 ppm, may require more frequent and aggressive regeneration.
The capacity of the activated alumina is greatly enhanced after conditioning. The first regeneration act as a conditioning step. Note that the first treatment of non-preconditioned AA will yield a capacity of 30% less than subsequent cycles after regeneration.