Evaluation of removal efficiency of fluoride from aqueous solution using quick lime

Several methods are available to remove fluoride from the aqueous environment but they are not feasible in all places and conditions due to various reasons. In the present work, F- has been removed by using activated and ordinary quick lime. The removal of fluoride was 80.6% and the final concentration was 9.7 mg/L at optimum condition from the synthetic solution having initial fluoride concentration of 50 mg/L. Adsorption kinetic study revealed that the adsorption process followed first order kinetics. And the removal process followed Langmuir adsorption isotherm. The SEM micrographs and XRD studies revealed that the removal of fluoride was mainly due to chemi-sorption and precipitation. However, they can be suitably used to remove fluoride from industrial effluent where the concentration is high. But this method cannot be employed to treat water for domestic purpose, since it cannot bring fluoride within permissible limit and also increases the pH of treated water. (C) 2006 Elsevier B.V. All rights reserved.