Removal of Fluoride from Contaminated Ground Water Using Raw and Modified Bauxite

Endemic fluorosis affects millions of people worldwide. Fluorosis arises from the consumption of fluorine (F) contaminated water and was observed also in some parts of Turkey with volcanic rocks and geothermal resources. In the present study the removal of F from drinking water by raw and modified bauxite at the laboratory scale was investigated using a batch mode. Modified bauxite was prepared by using Na and Mg incorporated (B–Na, B–Mg) bauxite and calcination of Mg incorporated bauxite at 500°C (B–Mg-500). The equilibration time for F between bauxite and water was identified to be 3 h. Adsorption of F increased with increasing adsorbent dose. Moreover, F adsorption isotherms fitted well with the Freundlich model. Low F adsorption was obtained onto the raw and incorporated bauxite. In contrast, maximum F adsorption was found for B–Mg-500, with Kf value of 0.247. This observation may be explained by the meaningfully stabilized and elevated number of positively charged sites in B–Mg-500.