Removal of Fluoride from water by Al(III)-loaded and Al(OH)(3)-coated chelating resin

An Al(III)-loaded and Al(OH)(3)-coated chelating resin Lewatit TP 260 was utilized for the removal of F- from aqueous solutions. Both forms of resin showed superior properties in the removal of F-. Removal performances of such resins were investigated extensively by adsorption isotherms and kinetic tests. It was revealed that maximum adsorption capacity of Al(OH)(3)-coated resin (0.55mg/g) was higher than Al(III)-loaded resin (0.40mg/g). The adsorption kinetics of both resins fitted well with the pseudo-second-order equation. The initial adsorption rate of Al(OH)(3)-coated resin was approximately seven times greater than Al(III)-loaded resin. The equilibrium isotherms have been investigated by using Langmuir and Freundlich isotherm equations and the obtained experimental data were best described by Langmuir model. The removal of F- by both forms of resin was accomplished by an anion-exchange mechanism. In the presence of Cl- and SO42-, removal performances of resins did not vary however, when the Al(III)-loaded resin was used, the presence of NO3- species reduced the removal efficiency of such resin.