REMOVAL OF FLUORIDE FROM AQUEOUS SOLUTIONS & SYNTHETIC SOLUTIONS BY VARIOUS ADSORBENTS - REVIEW

This study describes about the various adsorbents that have been used in the aqueous solutions and synthetic solutions to remove the fluoride concentration based on the surface area of the adsorbent. The capacity of the adsorbent depends upon the pH, contact time, initial concentration of the fluoride solution and Temperature etc. The fluoride level must be maintained at certain limits. For drinking purpose the fluoride ion concentration should be less than 1.5 mg/L as per Indian Standards. This review article is mainly aimed at providing precise information about the removal of fluoride in aqueous and synthetic solutions by adsorption technique that have been given by various researchers in the field of fluoride removal. Generally, the fluoride removal has been carried out by membrane and adsorption techniques. This paper deals with adsorption technique in which adsorbent used are titanium hydroxide, amorphous Fe/Al and other mixed hydroxides, algal biosorbent, schwertmannite, synthetic hydroxyapatite, earth oxides, granulated activated carbon and manganese oxides, clays and soils. Recent developments and the adsorption techniques have been clearly discussed.