Defluoridation studies of calcium and magnesium coating on activated alumina granules prepared by sol gel method

The contamination of fluoride in ground water has become global issue which has developed major threat to human health worldwide. Adsorption technique for water defluoridation is widely used method due to its greater accessibility and lower cost. Activated alumina is excellent adsorbent for fluoride removal however it has certain disadvantages like narrow operating pH range, formation of toxic fluoride complexes and metal leaching. To overcome these issues we have prepared calcium and magnesium coated activated alumina granules of size nearly 3 mm by hydrolysis of aluminum sulphate which is simple, cheap and economic method.The prepared granules were characterized and identified by XRD, FT-IR and SEM technique. The XRD, FT-IR and SEM micrographs confirms the formation of homogeneous and porous γ alumina phase with average particle size of around 45 nm. The fluoride removal capacity of the granules was investigated by column studies using freshly prepared fluoride stock solution. The calcium magnesium coated alumina granules shows decreased removal capacity than pure alumina granules however no formation of toxic aluminium complexes in the treated water were observed.