Role of metal ion incorporation in ion exchange resin on the selectivity of fluoride

Indion FR 10 resin has sulphonic acid functional group (H + form) possesses appreciable defluoridation capacity (DC) and its DC has been enhanced by chemical modification into Na + and Al 3+ forms by loading respective metal ions in H + form of resin. The DCs of Na + and Al 3+ forms were found to be 445 and 478 mg F −/kg, respectively, whereas the DC of H + form is 265 mg F (/kg at 10 mg/L initial fluoride concentration. The nature and morphology of sorbents are characterized using FTIR and SEM analysis. The fluoride sorption was explained using the Freundlich, Langmuir and Redlich–Peterson isotherms and kinetic models. The calculated thermodynamic parameters such as Δ G°, Δ H°, Δ S° and sticking probability ( S *) explains the nature of sorption. Comparison was also made by the elution capacity of these resins in order to select a cost effective material. A field trial was carried out to test the suitability of the resins with fluoride water collected from a nearby fluoride-endemic area.