Journal of Chemical Engineering of Japan, Vol.45, No.5, 331-336, 2012
Removal of Fluoride from Aqueous Solution by Using Porous Resins Containing Hydrated Oxide of Cerium(IV) and Zirconium(IV)
The adsorption behaviors of two types of commercial porous resins containing hydrated zirconium and cerium oxide, whose commercial names are READF-(PG) and READF-(HG), respectively, have been investigated relative to fluoride from aqueous solution. The adsorbents were characterized by XRD, EDX and surface area analyzer. Fluoride adsorption was found to be strongly pH dependent and optimum adsorption on both types of resins was observed at pH 2-4. The measurement of adsorption kinetics of fluoride demonstrated a fast adsorption process. The isotherm experiments showed Langmuir type monolayer adsorption. The complete removal of fluoride from trace concentration can be achieved using 4 g/L of the resins tested under the mentioned experimental condition. The maximum uptake capacity of the READF-(HG) and READF-(PG) were evaluated as 2.35 and 2.10 mmol F/g dry resin. The complete desorption of adsorbed fluoride was successfully achieved using a dilute alkali (NaOH) solution. Column adsorption followed by elution demonstrated the possible application of this system in a continuous system.